WorldWideScience

Sample records for resolution spectral survey

  1. Accurate Atmospheric Parameters at Moderate Resolution Using Spectral Indices: Preliminary Application to the MARVELS Survey

    Science.gov (United States)

    Ghezzi, Luan; Dutra-Ferreira, Letícia; Lorenzo-Oliveira, Diego; Porto de Mello, Gustavo F.; Santiago, Basílio X.; De Lee, Nathan; Lee, Brian L.; da Costa, Luiz N.; Maia, Marcio A. G.; Ogando, Ricardo L. C.; Wisniewski, John P.; González Hernández, Jonay I.; Stassun, Keivan G.; Fleming, Scott W.; Schneider, Donald P.; Mahadevan, Suvrath; Cargile, Phillip; Ge, Jian; Pepper, Joshua; Wang, Ji; Paegert, Martin

    2014-12-01

    Studies of Galactic chemical, and dynamical evolution in the solar neighborhood depend on the availability of precise atmospheric parameters (effective temperature T eff, metallicity [Fe/H], and surface gravity log g) for solar-type stars. Many large-scale spectroscopic surveys operate at low to moderate spectral resolution for efficiency in observing large samples, which makes the stellar characterization difficult due to the high degree of blending of spectral features. Therefore, most surveys employ spectral synthesis, which is a powerful technique, but relies heavily on the completeness and accuracy of atomic line databases and can yield possibly correlated atmospheric parameters. In this work, we use an alternative method based on spectral indices to determine the atmospheric parameters of a sample of nearby FGK dwarfs and subgiants observed by the MARVELS survey at moderate resolving power (R ~ 12,000). To avoid a time-consuming manual analysis, we have developed three codes to automatically normalize the observed spectra, measure the equivalent widths of the indices, and, through a comparison of those with values calculated with predetermined calibrations, estimate the atmospheric parameters of the stars. The calibrations were derived using a sample of 309 stars with precise stellar parameters obtained from the analysis of high-resolution FEROS spectra, permitting the low-resolution equivalent widths to be directly related to the stellar parameters. A validation test of the method was conducted with a sample of 30 MARVELS targets that also have reliable atmospheric parameters derived from the high-resolution spectra and spectroscopic analysis based on the excitation and ionization equilibria method. Our approach was able to recover the parameters within 80 K for T eff, 0.05 dex for [Fe/H], and 0.15 dex for log g, values that are lower than or equal to the typical external uncertainties found between different high-resolution analyses. An additional test was

  2. Accurate atmospheric parameters at moderate resolution using spectral indices: Preliminary application to the marvels survey

    International Nuclear Information System (INIS)

    Ghezzi, Luan; Da Costa, Luiz N.; Maia, Marcio A. G.; Ogando, Ricardo L. C.; Dutra-Ferreira, Letícia; Lorenzo-Oliveira, Diego; Porto de Mello, Gustavo F.; Santiago, Basílio X.; De Lee, Nathan; Lee, Brian L.; Ge, Jian; Wisniewski, John P.; González Hernández, Jonay I.; Stassun, Keivan G.; Cargile, Phillip; Pepper, Joshua; Fleming, Scott W.; Schneider, Donald P.; Mahadevan, Suvrath; Wang, Ji

    2014-01-01

    Studies of Galactic chemical, and dynamical evolution in the solar neighborhood depend on the availability of precise atmospheric parameters (effective temperature T eff , metallicity [Fe/H], and surface gravity log g) for solar-type stars. Many large-scale spectroscopic surveys operate at low to moderate spectral resolution for efficiency in observing large samples, which makes the stellar characterization difficult due to the high degree of blending of spectral features. Therefore, most surveys employ spectral synthesis, which is a powerful technique, but relies heavily on the completeness and accuracy of atomic line databases and can yield possibly correlated atmospheric parameters. In this work, we use an alternative method based on spectral indices to determine the atmospheric parameters of a sample of nearby FGK dwarfs and subgiants observed by the MARVELS survey at moderate resolving power (R ∼ 12,000). To avoid a time-consuming manual analysis, we have developed three codes to automatically normalize the observed spectra, measure the equivalent widths of the indices, and, through a comparison of those with values calculated with predetermined calibrations, estimate the atmospheric parameters of the stars. The calibrations were derived using a sample of 309 stars with precise stellar parameters obtained from the analysis of high-resolution FEROS spectra, permitting the low-resolution equivalent widths to be directly related to the stellar parameters. A validation test of the method was conducted with a sample of 30 MARVELS targets that also have reliable atmospheric parameters derived from the high-resolution spectra and spectroscopic analysis based on the excitation and ionization equilibria method. Our approach was able to recover the parameters within 80 K for T eff , 0.05 dex for [Fe/H], and 0.15 dex for log g, values that are lower than or equal to the typical external uncertainties found between different high-resolution analyses. An additional test

  3. Pristine Survey : High-Resolution Spectral Analyses of New Metal-poor Stars

    Science.gov (United States)

    Venn, Kim; Starkenburg, Else; Martin, Nicolas; Kielty, Collin; Youakim, Kris; Arnetsen, Anke

    2018-06-01

    The Pristine survey (Starkenburg et al. 2017) is a new and very successful metal-poor star survey. Combining high-quality narrow-band CaHK CFHT/MegaCam photometry with existing broadband photometry from SDSS, then very metal-poor stars have been found as confirmed from low-resolution spectroscopy (Youakim et al. 2017). Furthermore, we have extended this survey towards the Galactic bulge in a pilot program to test the capabilities in the highly crowded and (inhomogeneously) extincted bulge (Arentsen et al. 2018). High resolution spectral follow-up analyses have been initiated at the CFHT with Espadons (Vevolution or changes in the IMF, e.g., carbon enrichment, high [alpha/Fe] ratios vs alpha-challenged stars, and details in the neutron capture element ratios. While these early studies are being carried out using classical model atmospheres and synthetic spectral fitting (Venn et al. 2017, 2018), we are also exploring the use of a neural network for the fast, efficient, and precise determination of these stellar parameters and chemical abundances (e.g., StarNet, Fabbro et al. 2018).

  4. Cochlear implant users' spectral ripple resolution.

    Science.gov (United States)

    Jeon, Eun Kyung; Turner, Christopher W; Karsten, Sue A; Henry, Belinda A; Gantz, Bruce J

    2015-10-01

    This study revisits the issue of the spectral ripple resolution abilities of cochlear implant (CI) users. The spectral ripple resolution of recently implanted CI recipients (implanted during the last 10 years) were compared to those of CI recipients implanted 15 to 20 years ago, as well as those of normal-hearing and hearing-impaired listeners from previously published data from Henry, Turner, and Behrens [J. Acoust. Soc. Am. 118, 1111-1121 (2005)]. More recently, implanted CI recipients showed significantly better spectral ripple resolution. There is no significant difference in spectral ripple resolution for these recently implanted subjects compared to hearing-impaired (acoustic) listeners. The more recently implanted CI users had significantly better pre-operative speech perception than previously reported CI users. These better pre-operative speech perception scores in CI users from the current study may be related to better performance on the spectral ripple discrimination task; however, other possible factors such as improvements in internal and external devices cannot be excluded.

  5. Submicron Resolution Spectral-Domain Optical Coherence Tomography

    KAUST Repository

    Alarousu, Erkki; Jabbour, Ghassan

    2013-01-01

    Apparatuses and systems for submicron resolution spectral-domain optical coherence tomography (OCT) are disclosed. The system may use white light sources having wavelengths within 400-1000 nanometers, and achieve resolution below 1 .mu

  6. JUNO E/J/SS WAVES CALIBRATED SURVEY FULL RESOLUTION V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Juno Waves calibrated full resolution survey data set includes all low rate science electric spectral densities from 50Hz to 41MHz and magnetic spectral...

  7. High spectral resolution X-ray observations of AGN

    NARCIS (Netherlands)

    Kaastra, J.S.

    2008-01-01

    brief overview of some highlights of high spectral resolution X-ray observations of AGN is given, mainly obtained with the RGS of XMM-Newton. Future prospects for such observations with XMM-Newton are given.

  8. On spectral resolutions of differential vector-operators

    International Nuclear Information System (INIS)

    Ashurov, R.R.; Sokolov, M.S.

    2004-04-01

    We show that spectral resolutions of differential vector-operators may be represented as a specific direct sum integral operator with a kernel written in terms of generalized vector-operator eigenfunctions. Then we prove that a generalized eigenfunction measurable with respect to the spectral parameter may be decomposed using a set of analytical defining systems of coordinate operators. (author)

  9. Effects of NMR spectral resolution on protein structure calculation.

    Directory of Open Access Journals (Sweden)

    Suhas Tikole

    Full Text Available Adequate digital resolution and signal sensitivity are two critical factors for protein structure determinations by solution NMR spectroscopy. The prime objective for obtaining high digital resolution is to resolve peak overlap, especially in NOESY spectra with thousands of signals where the signal analysis needs to be performed on a large scale. Achieving maximum digital resolution is usually limited by the practically available measurement time. We developed a method utilizing non-uniform sampling for balancing digital resolution and signal sensitivity, and performed a large-scale analysis of the effect of the digital resolution on the accuracy of the resulting protein structures. Structure calculations were performed as a function of digital resolution for about 400 proteins with molecular sizes ranging between 5 and 33 kDa. The structural accuracy was assessed by atomic coordinate RMSD values from the reference structures of the proteins. In addition, we monitored also the number of assigned NOESY cross peaks, the average signal sensitivity, and the chemical shift spectral overlap. We show that high resolution is equally important for proteins of every molecular size. The chemical shift spectral overlap depends strongly on the corresponding spectral digital resolution. Thus, knowing the extent of overlap can be a predictor of the resulting structural accuracy. Our results show that for every molecular size a minimal digital resolution, corresponding to the natural linewidth, needs to be achieved for obtaining the highest accuracy possible for the given protein size using state-of-the-art automated NOESY assignment and structure calculation methods.

  10. The EUV dayglow at high spectral resolution

    International Nuclear Information System (INIS)

    Morrison, M.D.; Bowers, C.W.; Feldman, P.D.; Meier, R.R.

    1990-01-01

    Rocket observations of the dayglow spectrum of the terrestrial atmosphere between 840 angstrom and 1860 angstrom at 2 angstrom resolution were obtained with a sounding rocket payload flown on January 17, 1985. Additionally, spectra were also obtained using a 0.125-m focal length scanning Ebert-Fastie monochromator covering the wavelength interval of 1150-1550 angstrom at 7 angstrom resolution on this flight and on a sounding rocket flight on August 29, 1983, under similar viewing geometries and solar zenith angles. Three bands of the N 2 c' 4 system are seen clearly resolved in the dayglow. Analysis of high-resolution N 2 Lyman-Birge-Hopfield data shows no anomalous vibrational distribution as has been reported from other observations. The altitude profiles of the observed O and N 2 emissions demonstrate that the MSIS-83 model O and N 2 densities are appropriate for the conditions of both the 1983 and 1985 rocket flights. A reduction of a factor of 2 in the model O 2 density is required for both flights to reproduce the low-altitude atomic oxygen emission profiles. The volume excitation rates calculated using the Hinteregger et al. (1981) SC number-sign 21REFW solar reference spectrum and the photoelectron flux model of Strickland and Meier (1982) need to be scaled upward by a factor of 1.4 for both fights to match the observations

  11. Airborne Multi-Spectral Minefield Survey

    Science.gov (United States)

    2005-05-01

    Swedish Defence Research Agency), GEOSPACE (Austria), GTD ( Ingenieria de Sistemas y Software Industrial, Spain), IMEC (Ineruniversity MicroElectronic...RTO-MP-SET-092 18 - 1 UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED Airborne Multi-Spectral Minefield Survey Dirk-Jan de Lange, Eric den...actions is the severe lack of baseline information. To respond to this in a rapid way, cost-efficient data acquisition methods are a key issue. de

  12. LAMOST spectral survey — An overview

    International Nuclear Information System (INIS)

    Zhao Gang; Zhao Yongheng; Chu Yaoquan; Deng Licai; Jing Yipeng

    2012-01-01

    LAMOST (Large sky Area Multi-Object fiber Spectroscopic Telescope) is a Chinese national scientific research facility operated by National Astronomical Observatories, Chinese Academy of Sciences (NAOC). After two years of commissioning beginning in 2009, the telescope, instruments, software systems and operations are nearly ready to begin the main science survey. Through a spectral survey of millions of objects in much of the northern sky, LAMOST will enable research in a number of contemporary cutting edge topics in astrophysics, such as discovery of the first generation stars in the Galaxy, pinning down the formation and evolution history of galaxies — especially the Milky Way and its central massive black hole, and looking for signatures of the distribution of dark matter and possible sub-structures in the Milky Way halo. To maximize the scientific potential of the facility, wide national participation and international collaboration have been emphasized. The survey has two major components: the LAMOST ExtraGAlactic Survey (LEGAS) and the LAMOST Experiment for Galactic Understanding and Exploration (LEGUE). Until LAMOST reaches its full capability, the LEGUE portion of the survey will use the available observing time, starting in 2012. An overview of the LAMOST project and the survey that will be carried out in the next five to six years is presented in this paper. The science plan for the whole LEGUE survey, instrumental specifications, site conditions, and the descriptions of the current on-going pilot survey, including its footprints and target selection algorithm, will be presented as separate papers in this volume.

  13. High spectral resolution image of Barnacle Bill

    Science.gov (United States)

    1997-01-01

    The rover Sojourner's first target for measurement by the Alpha-Proton-Xray Spectrometer (APXS) was the rock named Barnacle Bill, located close to the ramp down which the rover made its egress from the lander. The full spectral capability of the Imager for Mars Pathfinder (IMP), consisting of 13 wavelength filters, was used to characterize the rock's surface. The measured area is relatively dark, and is shown in blue. Nearby on the rock surface, soil material is trapped in pits (shown in red).Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

  14. (LMRG): Microscope Resolution, Objective Quality, Spectral Accuracy and Spectral Un-mixing

    Science.gov (United States)

    Bayles, Carol J.; Cole, Richard W.; Eason, Brady; Girard, Anne-Marie; Jinadasa, Tushare; Martin, Karen; McNamara, George; Opansky, Cynthia; Schulz, Katherine; Thibault, Marc; Brown, Claire M.

    2012-01-01

    The second study by the LMRG focuses on measuring confocal laser scanning microscope (CLSM) resolution, objective lens quality, spectral imaging accuracy and spectral un-mixing. Affordable test samples for each aspect of the study were designed, prepared and sent to 116 labs from 23 countries across the globe. Detailed protocols were designed for the three tests and customized for most of the major confocal instruments being used by the study participants. One protocol developed for measuring resolution and objective quality was recently published in Nature Protocols (Cole, R. W., T. Jinadasa, et al. (2011). Nature Protocols 6(12): 1929–1941). The first study involved 3D imaging of sub-resolution fluorescent microspheres to determine the microscope point spread function. Results of the resolution studies as well as point spread function quality (i.e. objective lens quality) from 140 different objective lenses will be presented. The second study of spectral accuracy looked at the reflection of the laser excitation lines into the spectral detection in order to determine the accuracy of these systems to report back the accurate laser emission wavelengths. Results will be presented from 42 different spectral confocal systems. Finally, samples with double orange beads (orange core and orange coating) were imaged spectrally and the imaging software was used to un-mix fluorescence signals from the two orange dyes. Results from 26 different confocal systems will be summarized. Time will be left to discuss possibilities for the next LMRG study.

  15. Submicron Resolution Spectral-Domain Optical Coherence Tomography

    KAUST Repository

    Alarousu, Erkki

    2013-11-14

    Apparatuses and systems for submicron resolution spectral-domain optical coherence tomography (OCT) are disclosed. The system may use white light sources having wavelengths within 400-1000 nanometers, and achieve resolution below 1 .mu.m. The apparatus is aggregated into a unitary piece, and a user can connect the apparatus to a user provided controller and/or light source. The light source may be a supercontinuum source.

  16. Gamma-Ray Imager With High Spatial And Spectral Resolution

    Science.gov (United States)

    Callas, John L.; Varnell, Larry S.; Wheaton, William A.; Mahoney, William A.

    1996-01-01

    Gamma-ray instrument developed to enable both two-dimensional imaging at relatively high spatial resolution and spectroscopy at fractional-photon-energy resolution of about 10 to the negative 3rd power in photon-energy range from 10 keV to greater than 10 MeV. In its spectroscopic aspect, instrument enables identification of both narrow and weak gamma-ray spectral peaks.

  17. Linear and nonlinear optical spectroscopy: Spectral, temporal and spatial resolution

    DEFF Research Database (Denmark)

    Hvam, Jørn Marcher

    1997-01-01

    Selected linear and nonlinear optical spectroscopies are being described with special emphasis on the possibility of obtaining simultaneous spectral, temporal and spatial resolution. The potential of various experimental techniques is being demonstrated by specific examples mostly taken from inve...... investigations of the electronic, and opto-electronic, properties of semiconductor nanostructures....

  18. Evaluating the capabilities of vegetation spectral indices on chlorophyll content estimation at Sentinel-2 spectral resolutions

    Science.gov (United States)

    Sun, Qi; Jiao, Quanjun; Dai, Huayang

    2018-03-01

    Chlorophyll is an important pigment in green plants for photosynthesis and obtaining the energy for growth and development. The rapid, nondestructive and accurate estimation of chlorophyll content is significant for understanding the crops growth, monitoring the disease and insect, and assessing the yield of crops. Sentinel-2 equipped with the Multi-Spectral Instrument (MSI), which will provide images with high spatial, spectral and temporal resolution. It covers the VNIR/SWIR spectral region in 13 bands and incorporates two new spectral bands in the red-edge region and a spatial resolution of 20nm, which can be used to derive vegetation indices using red-edge bands. In this paper, we will focus on assessing the potential of vegetation spectral indices for retrieving chlorophyll content from Sentinel-2 at different angles. Subsequently, we used in-situ spectral data and Sentinel-2 data to test the relationship between VIs and chlorophyll content. The REP, MTCI, CIred-edge, CIgreen, Macc01, TCARI/OSAVI [705,750], NDRE1 and NDRE2 were calculated. NDRE2 index displays a strongly similar result for hyperspectral and simulated Sentinel-2 spectral bands (R2 =0.53, R2 =0.51, for hyperspectral and Sentinel-2, respectively). At different observation angles, NDRE2 has the smallest difference in performance (R2 = 0.51, R2 =0.64, at 0° and 15° , respectively).

  19. The SPHEREx All-Sky Spectral Survey

    Science.gov (United States)

    Bock, James; SPHEREx Science Team

    2018-01-01

    SPHEREx, a mission in NASA's Medium Explorer (MIDEX) program that was selected for Phase A in August 2017, is an all-sky survey satellite designed to address all three science goals in NASA's astrophysics division, with a single instrument, a wide-field spectral imager. SPHEREx will probe the physics of inflation by measuring non-Gaussianity by studying large-scale structure, surveying a large cosmological volume at low redshifts, complementing high-z surveys optimized to constrain dark energy. The origin of water and biogenic molecules will be investigated in all phases of planetary system formation - from molecular clouds to young stellar systems with protoplanetary disks - by measuring ice absorption spectra. We will chart the origin and history of galaxy formation through a deep survey mapping large-scale spatial power in two deep fields located near the ecliptic poles. Following in the tradition of all-sky missions such as IRAS, COBE and WISE, SPHEREx will be the first all-sky near-infrared spectral survey. SPHEREx will create spectra (0.75 – 4.2 um at R = 41; and 4.2 – 5 um at R = 135) with high sensitivity making background-limited observations using a passively-cooled telescope with a wide field-of-view for large mapping speed. During its two-year mission, SPHEREx will produce four complete all-sky maps that will serve as a rich archive for the astronomy community. With over a billion detected galaxies, hundreds of millions of high-quality stellar and galactic spectra, and over a million ice absorption spectra, the archive will enable diverse scientific investigations including studies of young stellar systems, brown dwarfs, high-redshift quasars, galaxy clusters, the interstellar medium, asteroids and comets. All aspects of the instrument and spacecraft have high heritage. SPHEREx requires no new technologies and carries large technical and resource margins on every aspect of the design. SPHEREx is a partnership between Caltech and JPL, following the

  20. High spectral resolution infrared observations of V1057 Cygni

    International Nuclear Information System (INIS)

    Hartmann, L.; Kenyon, S.J.

    1987-01-01

    High-resolution near-infrared spectra of V1057 Cygni obtained in 1986 with the KPNO 4-m Fourier transform spectrometer provide support for a previously proposed accretion disk model. The model predicts that the observed rotational broadening of spectral lines should be smaller in the infrared than in the optical. The present observations show that V1057 Cyg rotates more slowly at 2.3 microns than at 6000 A by an amount quantitatively consistent with the simple disk models. The absence of any radial velocity variations in either the infrared or optical spectral regions supports the suggestion that the accreted material arises from a remnant disk of protostellar material. 19 references

  1. Planning for shallow high resolution seismic surveys

    CSIR Research Space (South Africa)

    Fourie, CJS

    2008-11-01

    Full Text Available of the input wave. This information can be used in conjunction with this spreadsheet to aid the geophysicist in designing shallow high resolution seismic surveys to achieve maximum resolution and penetration. This Excel spreadsheet is available free from...

  2. a Spatio-Spectral Camera for High Resolution Hyperspectral Imaging

    Science.gov (United States)

    Livens, S.; Pauly, K.; Baeck, P.; Blommaert, J.; Nuyts, D.; Zender, J.; Delauré, B.

    2017-08-01

    Imaging with a conventional frame camera from a moving remotely piloted aircraft system (RPAS) is by design very inefficient. Less than 1 % of the flying time is used for collecting light. This unused potential can be utilized by an innovative imaging concept, the spatio-spectral camera. The core of the camera is a frame sensor with a large number of hyperspectral filters arranged on the sensor in stepwise lines. It combines the advantages of frame cameras with those of pushbroom cameras. By acquiring images in rapid succession, such a camera can collect detailed hyperspectral information, while retaining the high spatial resolution offered by the sensor. We have developed two versions of a spatio-spectral camera and used them in a variety of conditions. In this paper, we present a summary of three missions with the in-house developed COSI prototype camera (600-900 nm) in the domains of precision agriculture (fungus infection monitoring in experimental wheat plots), horticulture (crop status monitoring to evaluate irrigation management in strawberry fields) and geology (meteorite detection on a grassland field). Additionally, we describe the characteristics of the 2nd generation, commercially available ButterflEYE camera offering extended spectral range (475-925 nm), and we discuss future work.

  3. A SPATIO-SPECTRAL CAMERA FOR HIGH RESOLUTION HYPERSPECTRAL IMAGING

    Directory of Open Access Journals (Sweden)

    S. Livens

    2017-08-01

    Full Text Available Imaging with a conventional frame camera from a moving remotely piloted aircraft system (RPAS is by design very inefficient. Less than 1 % of the flying time is used for collecting light. This unused potential can be utilized by an innovative imaging concept, the spatio-spectral camera. The core of the camera is a frame sensor with a large number of hyperspectral filters arranged on the sensor in stepwise lines. It combines the advantages of frame cameras with those of pushbroom cameras. By acquiring images in rapid succession, such a camera can collect detailed hyperspectral information, while retaining the high spatial resolution offered by the sensor. We have developed two versions of a spatio-spectral camera and used them in a variety of conditions. In this paper, we present a summary of three missions with the in-house developed COSI prototype camera (600–900 nm in the domains of precision agriculture (fungus infection monitoring in experimental wheat plots, horticulture (crop status monitoring to evaluate irrigation management in strawberry fields and geology (meteorite detection on a grassland field. Additionally, we describe the characteristics of the 2nd generation, commercially available ButterflEYE camera offering extended spectral range (475–925 nm, and we discuss future work.

  4. Atmospheric stellar parameters for large surveys using FASMA, a new spectral synthesis package

    Science.gov (United States)

    Tsantaki, M.; Andreasen, D. T.; Teixeira, G. D. C.; Sousa, S. G.; Santos, N. C.; Delgado-Mena, E.; Bruzual, G.

    2018-02-01

    In the era of vast spectroscopic surveys focusing on Galactic stellar populations, astronomers want to exploit the large quantity and good quality of data to derive their atmospheric parameters without losing precision from automatic procedures. In this work, we developed a new spectral package, FASMA, to estimate the stellar atmospheric parameters (namely effective temperature, surface gravity and metallicity) in a fast and robust way. This method is suitable for spectra of FGK-type stars in medium and high resolution. The spectroscopic analysis is based on the spectral synthesis technique using the radiative transfer code, MOOG. The line list is comprised of mainly iron lines in the optical spectrum. The atomic data are calibrated after the Sun and Arcturus. We use two comparison samples to test our method, (i) a sample of 451 FGK-type dwarfs from the high-resolution HARPS spectrograph; and (ii) the Gaia-ESO benchmark stars using both high and medium resolution spectra. We explore biases in our method from the analysis of synthetic spectra covering the parameter space of our interest. We show that our spectral package is able to provide reliable results for a wide range of stellar parameters, different rotational velocities, different instrumental resolutions and for different spectral regions of the VLT-GIRAFFE spectrographs, used amongst others for the Gaia-ESO survey. FASMA estimates stellar parameters in less than 15 m for high-resolution and 3 m for medium-resolution spectra. The complete package is publicly available to the community.

  5. Extension of least squares spectral resolution algorithm to high-resolution lipidomics data

    International Nuclear Information System (INIS)

    Zeng, Ying-Xu; Mjøs, Svein Are; David, Fabrice P.A.; Schmid, Adrien W.

    2016-01-01

    Lipidomics, which focuses on the global study of molecular lipids in biological systems, has been driven tremendously by technical advances in mass spectrometry (MS) instrumentation, particularly high-resolution MS. This requires powerful computational tools that handle the high-throughput lipidomics data analysis. To address this issue, a novel computational tool has been developed for the analysis of high-resolution MS data, including the data pretreatment, visualization, automated identification, deconvolution and quantification of lipid species. The algorithm features the customized generation of a lipid compound library and mass spectral library, which covers the major lipid classes such as glycerolipids, glycerophospholipids and sphingolipids. Next, the algorithm performs least squares resolution of spectra and chromatograms based on the theoretical isotope distribution of molecular ions, which enables automated identification and quantification of molecular lipid species. Currently, this methodology supports analysis of both high and low resolution MS as well as liquid chromatography-MS (LC-MS) lipidomics data. The flexibility of the methodology allows it to be expanded to support more lipid classes and more data interpretation functions, making it a promising tool in lipidomic data analysis. - Highlights: • A flexible strategy for analyzing MS and LC-MS data of lipid molecules is proposed. • Isotope distribution spectra of theoretically possible compounds were generated. • High resolution MS and LC-MS data were resolved by least squares spectral resolution. • The method proposed compounds that are likely to occur in the analyzed samples. • The proposed compounds matched results from manual interpretation of fragment spectra.

  6. Extension of least squares spectral resolution algorithm to high-resolution lipidomics data

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Ying-Xu [Department of Chemistry, University of Bergen, PO Box 7803, N-5020 Bergen (Norway); Mjøs, Svein Are, E-mail: svein.mjos@kj.uib.no [Department of Chemistry, University of Bergen, PO Box 7803, N-5020 Bergen (Norway); David, Fabrice P.A. [Bioinformatics and Biostatistics Core Facility, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL) and Swiss Institute of Bioinformatics (SIB), Lausanne (Switzerland); Schmid, Adrien W. [Proteomics Core Facility, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

    2016-03-31

    Lipidomics, which focuses on the global study of molecular lipids in biological systems, has been driven tremendously by technical advances in mass spectrometry (MS) instrumentation, particularly high-resolution MS. This requires powerful computational tools that handle the high-throughput lipidomics data analysis. To address this issue, a novel computational tool has been developed for the analysis of high-resolution MS data, including the data pretreatment, visualization, automated identification, deconvolution and quantification of lipid species. The algorithm features the customized generation of a lipid compound library and mass spectral library, which covers the major lipid classes such as glycerolipids, glycerophospholipids and sphingolipids. Next, the algorithm performs least squares resolution of spectra and chromatograms based on the theoretical isotope distribution of molecular ions, which enables automated identification and quantification of molecular lipid species. Currently, this methodology supports analysis of both high and low resolution MS as well as liquid chromatography-MS (LC-MS) lipidomics data. The flexibility of the methodology allows it to be expanded to support more lipid classes and more data interpretation functions, making it a promising tool in lipidomic data analysis. - Highlights: • A flexible strategy for analyzing MS and LC-MS data of lipid molecules is proposed. • Isotope distribution spectra of theoretically possible compounds were generated. • High resolution MS and LC-MS data were resolved by least squares spectral resolution. • The method proposed compounds that are likely to occur in the analyzed samples. • The proposed compounds matched results from manual interpretation of fragment spectra.

  7. Geological survey by high resolution electrical survey on granite areas

    International Nuclear Information System (INIS)

    Sugimoto, Yoshihiro; Yamada, Naoyuki

    2002-03-01

    As an Integral part of the geological survey in 'The study of the regions ground water flow system' that we are carrying out with Tono Geoscience Center, we proved the relation between the uncontinuation structure such as lineament in the base rock and resistivity structure (resistivity distribution), for the purpose of that confirms the efficacy of the high resolution electrical survey as geological survey, we carried out high resolution electrical survey on granite area. We obtained the following result, by the comparison of resistivity distribution with established geological survey, lineament analysis and investigative drilling. 1. The resistivity structure of this survey area is almost able to classify it into the following four range. 1) the low resistivity range of 50-800 Ωm, 2) The resistivity range like the middle of 200-2000 Ωm, 3) The high resistivity range of 2000 Ωm over, 4) The low resistivity range of depth of the survey line 400-550 section. 2. The low resistivity range of 4) that correspond with the established geological data is not admitted. 3. It was confirmed that resistivity structure almost correspond to geological structure by the comparison with the established data. 4. The small-scale low resistivity area is admitted in the point equivalent to the lineament position of established. 5. We carried out it with the simulation method about the low resistivity range of 4). As a result, it understood that it has the possibility that the narrow ratio low resistivity area is shown as the wide ratio resistivity range in the analysis section. In the survey in this time, it is conceivable that the resistivity distribution with the possibility of the unhomogeneous and uncontinuation structure of the base rock is being shown conspicuously, the efficacy of the high resolution resistivity survey as geological survey on granite was shown. (author)

  8. Breast density estimation from high spectral and spatial resolution MRI

    Science.gov (United States)

    Li, Hui; Weiss, William A.; Medved, Milica; Abe, Hiroyuki; Newstead, Gillian M.; Karczmar, Gregory S.; Giger, Maryellen L.

    2016-01-01

    Abstract. A three-dimensional breast density estimation method is presented for high spectral and spatial resolution (HiSS) MR imaging. Twenty-two patients were recruited (under an Institutional Review Board--approved Health Insurance Portability and Accountability Act-compliant protocol) for high-risk breast cancer screening. Each patient received standard-of-care clinical digital x-ray mammograms and MR scans, as well as HiSS scans. The algorithm for breast density estimation includes breast mask generating, breast skin removal, and breast percentage density calculation. The inter- and intra-user variabilities of the HiSS-based density estimation were determined using correlation analysis and limits of agreement. Correlation analysis was also performed between the HiSS-based density estimation and radiologists’ breast imaging-reporting and data system (BI-RADS) density ratings. A correlation coefficient of 0.91 (pdensity estimations. An interclass correlation coefficient of 0.99 (pdensity estimations. A moderate correlation coefficient of 0.55 (p=0.0076) was observed between HiSS-based breast density estimations and radiologists’ BI-RADS. In summary, an objective density estimation method using HiSS spectral data from breast MRI was developed. The high reproducibility with low inter- and low intra-user variabilities shown in this preliminary study suggest that such a HiSS-based density metric may be potentially beneficial in programs requiring breast density such as in breast cancer risk assessment and monitoring effects of therapy. PMID:28042590

  9. Field-widened Michelson interferometer for spectral discrimination in high-spectral-resolution lidar: theoretical framework.

    Science.gov (United States)

    Cheng, Zhongtao; Liu, Dong; Luo, Jing; Yang, Yongying; Zhou, Yudi; Zhang, Yupeng; Duan, Lulin; Su, Lin; Yang, Liming; Shen, Yibing; Wang, Kaiwei; Bai, Jian

    2015-05-04

    A field-widened Michelson interferometer (FWMI) is developed to act as the spectral discriminator in high-spectral-resolution lidar (HSRL). This realization is motivated by the wide-angle Michelson interferometer (WAMI) which has been used broadly in the atmospheric wind and temperature detection. This paper describes an independent theoretical framework about the application of the FWMI in HSRL for the first time. In the framework, the operation principles and application requirements of the FWMI are discussed in comparison with that of the WAMI. Theoretical foundations for designing this type of interferometer are introduced based on these comparisons. Moreover, a general performance estimation model for the FWMI is established, which can provide common guidelines for the performance budget and evaluation of the FWMI in the both design and operation stages. Examples incorporating many practical imperfections or conditions that may degrade the performance of the FWMI are given to illustrate the implementation of the modeling. This theoretical framework presents a complete and powerful tool for solving most of theoretical or engineering problems encountered in the FWMI application, including the designing, parameter calibration, prior performance budget, posterior performance estimation, and so on. It will be a valuable contribution to the lidar community to develop a new generation of HSRLs based on the FWMI spectroscopic filter.

  10. Field-widened Michelson interferometer for spectral discrimination in high-spectral-resolution lidar: practical development.

    Science.gov (United States)

    Cheng, Zhongtao; Liu, Dong; Zhang, Yupeng; Yang, Yongying; Zhou, Yudi; Luo, Jing; Bai, Jian; Shen, Yibing; Wang, Kaiwei; Liu, Chong; Su, Lin; Yang, Liming

    2016-04-04

    A field-widened Michelson interferometer (FWMI), which is intended as the spectroscopic discriminator in ground-based high-spectral-resolution lidar (HSRL) for atmospheric aerosol detection, is described in this paper. The structure, specifications and design of the developed prototype FWMI are introduced, and an experimental approach is proposed to optimize the FWMI assembly and evaluate its comprehensive characteristic simultaneously. Experimental results show that, after optimization process, the peak-to-valley (PV) value and root-mean-square (RMS) value of measured OPD variation for the FWMI are 0.04λ and 0.008λ respectively among the half divergent angle range of 1.5 degree. Through an active locking technique, the frequency of the FWMI can be locked to the laser transmitter with accuracy of 27 MHz for more than one hour. The practical spectral discrimination ratio (SDR) for the developed FWMI is evaluated to be larger than 86 if the divergent angle of incident beam is smaller than 0.5 degree. All these results demonstrate the great potential of the developed FWMI as the spectroscopic discriminator for HSRLs, as well as the feasibility of the proposed design and optimization process. This paper is expected to provide a good entrance for the lidar community in future HSRL developments using the FWMI technique.

  11. Assessment of modern spectral analysis methods to improve wavenumber resolution of F-K spectra

    International Nuclear Information System (INIS)

    Shirley, T.E.; Laster, S.J.; Meek, R.A.

    1987-01-01

    The improvement in wavenumber spectra obtained by using high resolution spectral estimators is examined. Three modern spectral estimators were tested, namely the Autoregressive/Maximum Entropy (AR/ME) method, the Extended Prony method, and an eigenstructure method. They were combined with the conventional Fourier method by first transforming each trace with a Fast Fourier Transform (FFT). A high resolution spectral estimator was applied to the resulting complex spatial sequence for each frequency. The collection of wavenumber spectra thus computed comprises a hybrid f-k spectrum with high wavenumber resolution and less spectral ringing. Synthetic and real data records containing 25 traces were analyzed by using the hybrid f-k method. The results show an FFT-AR/ME f-k spectrum has noticeably better wavenumber resolution and more spectral dynamic range than conventional spectra when the number of channels is small. The observed improvement suggests the hybrid technique is potentially valuable in seismic data analysis

  12. Spectral resolution control of acousto-optical cells operating with collimated and divergent beams

    Science.gov (United States)

    Voloshinov, Vitaly B.; Mishin, Dimitry D.

    1994-01-01

    The paper is devoted to theoretical and experimental investigations of acousto-optical interactions in crystals which may be used for spectral filtration of light in tunable acousto- optical filters. Attention is paid to spectral resolution control during operation with divergent or collimated noncoherent optical beams. In all examined cases spectral bands of anisotropic Bragg diffraction were regulated by means of novel electronical methods. Resolution control was achieved in paratellurite cells with non-collinear and quasi-collinear regimes of the diffraction. Filtration spectral bandwidths for visible light were electronically changed by a factor of 10 divided by 20 by drive electrical signals switching and drive electrical power regulations.

  13. Time-resolved High Spectral Resolution Observation of 2MASSW J0746425+200032AB

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ji; Mawet, Dimitri [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 E. California Boulevard, Pasadena, CA 91106 (United States); Prato, Lisa, E-mail: ji.wang@caltech.edu [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)

    2017-03-20

    Many brown dwarfs (BDs) exhibit photometric variability at levels from tenths to tens of percents. The photometric variability is related to magnetic activity or patchy cloud coverage, characteristic of BDs near the L–T transition. Time-resolved spectral monitoring of BDs provides diagnostics of cloud distribution and condensate properties. However, current time-resolved spectral studies of BDs are limited to low spectral resolution ( R ∼ 100) with the exception of the study of Luhman 16 AB at a resolution of 100,000 using the VLT+CRIRES. This work yielded the first map of BD surface inhomogeneity, highlighting the importance and unique contribution of high spectral resolution observations. Here, we report on the time-resolved high spectral resolution observations of a nearby BD binary, 2MASSW J0746425+200032AB. We find no coherent spectral variability that is modulated with rotation. Based on simulations, we conclude that the coverage of a single spot on 2MASSW J0746425+200032AB is smaller than 1% or 6.25% if spot contrast is 50% or 80% of its surrounding flux, respectively. Future high spectral resolution observations aided by adaptive optics systems can put tighter constraints on the spectral variability of 2MASSW J0746425+200032AB and other nearby BDs.

  14. High Spectral Resolution, High Cadence, Imaging X-ray Microcalorimeters for Solar Physics - Phase 2 Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Microcalorimeter x-ray instruments are non-dispersive, high spectral resolution, broad-band, high cadence imaging spectrometers. We have been developing these...

  15. On the use of spectral minutiae in high-resolution palmprint recognition

    NARCIS (Netherlands)

    Wang, Ruifang; Veldhuis, Raymond N.J.; Ramos, Daniel; Spreeuwers, Lieuwe Jan; Fierrez, Julian; Xu, H.

    2013-01-01

    The spectral minutiae representation has been proposed as a novel method to minutiae-based fingerprint recognition, which can handle minutiae translation and rotation and improve matching speed. As high-resolution palmprint recognition is also mainly based on minutiae sets, we apply spectral

  16. Infrared emission high spectral resolution atlas of the stratospheric limb

    Science.gov (United States)

    Maguire, William C.; Kunde, Virgil G.; Herath, Lawrence W.

    1989-01-01

    An atlas of high resolution infrared emission spectra identifies a number of gaseous atmospheric features significant to stratospheric chemistry in the 770-900/cm and 1100-1360/cm regions at six zenith angles from 86.7 to 95.1 deg. A balloon-borne Michelson interferometer was flown to obtain about 0.03/cm resolution spectra. Two 10/cm extracts are presented here.

  17. Analysis of X-ray Spectra of High-Z Elements obtained on Nike with high spectral and spatial resolution

    Science.gov (United States)

    Aglitskiy, Yefim; Weaver, J. L.; Karasik, M.; Serlin, V.; Obenschain, S. P.; Ralchenko, Yu.

    2014-10-01

    The spectra of multi-charged ions of Hf, Ta, W, Pt, Au and Bi have been studied on Nike krypton-fluoride laser facility with the help of two kinds of X-ray spectrometers. First, survey instrument covering a spectral range from 0.5 to 19.5 angstroms which allows simultaneous observation of both M- and N- spectra of above mentioned elements with high spectral resolution. Second, an imaging spectrometer with interchangeable spherically bent Quartz crystals that added higher efficiency, higher spectral resolution and high spatial resolution to the qualities of the former one. Multiple spectral lines with X-ray energies as high as 4 keV that belong to the isoelectronic sequences of Fe, Co, Ni, Cu and Zn were identified with the help of NOMAD package developed by Dr. Yu. Ralchenko and colleagues. In our continuous effort to support DOE-NNSA's inertial fusion program, this campaign covered a wide range of plasma conditions that result in production of relatively energetic X-rays. Work supported by the US DOE/NNSA.

  18. Atmospheric-water absorption features near 2.2 micrometers and their importance in high spectral resolution remote sensing

    Science.gov (United States)

    Kruse, F. A.; Clark, R. N.

    1986-01-01

    Selective absorption of electromagnetic radiation by atmospheric gases and water vapor is an accepted fact in terrestrial remote sensing. Until recently, only a general knowledge of atmospheric effects was required for analysis of remote sensing data; however, with the advent of high spectral resolution imaging devices, detailed knowledge of atmospheric absorption bands has become increasingly important for accurate analysis. Detailed study of high spectral resolution aircraft data at the U.S. Geological Survey has disclosed narrow absorption features centered at approximately 2.17 and 2.20 micrometers not caused by surface mineralogy. Published atmospheric transmission spectra and atmospheric spectra derived using the LOWTRAN-5 computer model indicate that these absorption features are probably water vapor. Spectral modeling indicates that the effects of atmospheric absorption in this region are most pronounced in spectrally flat materials with only weak absorption bands. Without correction and detailed knowledge of the atmospheric effects, accurate mapping of surface mineralogy (particularly at low mineral concentrations) is not possible.

  19. Accuracy in mineral identification: image spectral and spatial resolutions and mineral spectral properties

    Directory of Open Access Journals (Sweden)

    L. Pompilio

    2006-06-01

    Full Text Available Problems related to airborne hyperspectral image data are reviewed and the requirements for data analysis applied to mineralogical (rocks and soils interpretation are discussed. The variability of mineral spectral features, including absorption position, shape and depth is considered and interpreted as due to chemical composition, grain size effects and mineral association. It is also shown how this variability can be related to well defined geologic processes. The influence of sensor noise and diffuse atmospheric radiance in classification accuracy is also analyzed.

  20. A Concept of Multi-Mode High Spectral Resolution Lidar Using Mach-Zehnder Interferometer

    Directory of Open Access Journals (Sweden)

    Jin Yoshitaka

    2016-01-01

    Full Text Available In this paper, we present the design of a High Spectral Resolution Lidar (HSRL using a laser that oscillates in a multi-longitudinal mode. Rayleigh and Mie scattering components are separated using a Mach-Zehnder Interferometer (MZI with the same free spectral range (FSR as the transmitted laser. The transmitted laser light is measured as a reference signal with the same MZI. By scanning the MZI periodically with a scanning range equal to the mode spacing, we can identify the maximum Mie and the maximum Rayleigh signals using the reference signal. The cross talk due to the spectral width of each laser mode can also be estimated.

  1. SWIFTS: on-chip very high spectral resolution spectrometer

    Science.gov (United States)

    le Coarer, E.; Venancio, L. G.; Kern, P.; Ferrand, J.; Puget, P.; Ayraud, M.; Bonneville, C.; Demonte, B.; Morand, A.; Boussey, J.; Barbier, D.; Blaize, S.; Gonthiez, T.

    2017-11-01

    The size and the weight of state of the art spectrometers is a serious issue regarding space applications. SWIFTS (Stationary Wave Integrated Fourier Transform Spectrometer) is a new FTS family without any moving part. This very promising technology is an original way to fully sample the Fourier interferogram obtained in a waveguide by either a reflection (SWIFTS Lippmann) or counter-propagative (SWIFTS Gabor) interference phenomenon. The sampling is simultaneously performed the optical path thanks to "nano-detectors" located in the evanescent field of the waveguide. For instance a 1.7cm long waveguide properly associated to the detector achieves directly a resolution of 0.13cm-1 on a few centimetre long instruments. Here, firstly we present the development status of this new kind of spectrometers and the first results obtained with on going development of spectrometer covering simultaneously the visible domain from 400 to 1000 nm like an Echelle spectrometer. Valuable technologies allows one to extend the concept to various wavelength domains. Secondly, we present the results obtained in the frame of an activity funded by the European Space Agency where several potential applications in space missions have been identified and studied.

  2. Impact of the cameras radiometric resolution on the accuracy of determining spectral reflectance coefficients

    Science.gov (United States)

    Orych, A.; Walczykowski, P.; Jenerowicz, A.; Zdunek, Z.

    2014-11-01

    Nowadays remote sensing plays a very important role in many different study fields, i.e. environmental studies, hydrology, mineralogy, ecosystem studies, etc. One of the key areas of remote sensing applications is water quality monitoring. Understanding and monitoring of the water quality parameters and detecting different water contaminants is an important issue in water management and protection of whole environment and especially the water ecosystem. There are many remote sensing methods to monitor water quality and detect water pollutants. One of the most widely used method for substance detection with remote sensing techniques is based on usage of spectral reflectance coefficients. They are usually acquired using discrete methods such as spectrometric measurements. These however can be very time consuming, therefore image-based methods are used more and more often. In order to work out the proper methodology of obtaining spectral reflectance coefficients from hyperspectral and multispectral images, it is necessary to verify the impact of cameras radiometric resolution on the accuracy of determination of them. This paper presents laboratory experiments that were conducted using two monochromatic XEVA video sensors (400-1700 nm spectral data registration) with two different radiometric resolutions (12 and 14 bits). In view of determining spectral characteristics from images, the research team used set of interferometric filters. All data collected with multispectral digital video cameras were compared with spectral reflectance coefficients obtained with spectroradiometer. The objective of this research is to find the impact of cameras radiometric resolution on reflectance values in chosen wavelength. The main topic of this study is the analysis of accuracy of spectral coefficients from sensors with different radiometric resolution. By comparing values collected from images acquired with XEVA sensors and with the curves obtained with spectroradiometer it

  3. SOFIA/EXES High Spectral Resolution Observations of the Orion Hot Core

    Science.gov (United States)

    Rangwala, Naseem; Colgan, Sean; Le Gal, Romane; Acharya, Kinsuk; Huang, Xinchuan; Herbst, Eric; Lee, Timothy J.; Richter, Matthew J.; Boogert, Adwin

    2018-01-01

    The Orion hot core has one of the richest molecular chemistries observed in the ISM. In the MIR, the Orion hot core composition is best probed by the closest, compact, bright background continuum source in this region, IRc2. We present high-spectral resolution observations from 12.96 - 13.33 μm towards Orion IRc2 using the mid-infrared spectrograph, EXES, on SOFIA, to probe the physical and chemical conditions of the Orion hot core. All ten of the rovibrational C2H2 transitions expected in our spectral coverage, are detected with high S/N, yielding continuous coverage of the R-branch lines from J=9-8 to J=18-17, including both ortho and para species. Eight of these rovibrational transitions are newly reported detections. These data show distinct ortho and para ladders towards the Orion hot core for the first time, with an ortho to para ratio (OPR) of only 0.6 - much lower than the high temperature equilibrium value of 3. A non-equilibrium OPR is a further indication of the Orion hot core being heated externally by shocks likely resulting from a well-known explosive event which occurred 500 yrs ago. The OPR conversion timescales are much longer than the 500 yr shock timescale and thus a low OPR might be a remnant from an earlier colder pre-stellar phase before the density enhancement (now the hot core) was impacted by shocks.We will also present preliminary results from an on-going SOFIA Cycle-5 impact program to use EXES to conduct an unbiased, high-S/N, continuous, molecular line survey of the Orion hot core from 12.5 - 28.3 microns. This survey is expected to be 50 times better than ISO in detecting isolated, narrow lines to (a) resolve the ro-vibrational structure of the gas phase molecules and their kinematics, (b) detect new gas phase molecules missed by ISO, and (c) provide useful constraints on the hot core chemistry and the source of Orion hot core excitation. This survey will greatly enhance the inventory of resolved line features in the MIR for hot cores

  4. Radio stars observed in the LAMOST spectral survey

    Science.gov (United States)

    Zhang, Li-Yun; Yue, Qiang; Lu, Hong-Peng; Han, Xian-Ming L.; Zhang, Yong; Shi, Jian-Rong; Wang, Yue-Fei; Hou, Yong-Hui; Zi-Huang, Cao

    2017-09-01

    Radio stars have attracted astronomers’ attention for several decades. To better understand the physics behind stellar radio emissions, it is important to study their optical behaviors. The LAMOST survey provides a large database for researching stellar spectroscopic properties of radio stars. In this work, we concentrate on their spectroscopic properties and infer physical properties from their spectra, such as stellar activity and variability. We mined big data from the LAMOST spectral survey Data Release 2 (DR2), published on 2016 June 30, by cross-matching them with radio stars from FIRST and other surveys. We obtained 783 good stellar spectra with high signal to noise ratio for 659 stars. The criteria for selection were positional coincidence within 1.5‧‧ and LAMOST objects classified as stars. We calculated the equivalent widths (EWs) of the Ca ii H&K, Hδ, Hγ, Hβ, Hα and Ca ii IRT lines by integrating the line profiles. Using the EWs of the Hα line, we detected 147 active stellar spectra of 89 objects having emissions above the Hα continuum. There were also 36 objects with repeated spectra, 28 of which showed chromospheric activity variability. Furthermore, we found 14 radio stars emitting noticeably in the Ca ii IRT lines. The low value of the EW8542/EW8498 ratio for these 14 radio stars possibly alludes to chromospheric plage regions.

  5. Deep, Broadband Spectral Line Surveys of Molecule-rich Interstellar Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Widicus Weaver, Susanna L.; Laas, Jacob C.; Zou, Luyao; Kroll, Jay A.; Rad, Mary L.; Hays, Brian M.; Sanders, James L.; Cross, Trevor N.; Wehres, Nadine; McGuire, Brett A. [Department of Chemistry, Emory University, Atlanta, GA 30322 (United States); Lis, Dariusz C.; Sumner, Matthew C., E-mail: susanna.widicus.weaver@emory.edu [California Institute of Technology, Cahill Center for Astronomy and Astrophysics 301-17, Pasadena, CA 91125 (United States)

    2017-09-01

    Spectral line surveys are an indispensable tool for exploring the physical and chemical evolution of astrophysical environments due to the vast amount of data that can be obtained in a relatively short amount of time. We present deep, broadband spectral line surveys of 30 interstellar clouds using two broadband λ  = 1.3 mm receivers at the Caltech Submillimeter Observatory. This information can be used to probe the influence of physical environment on molecular complexity. We observed a wide variety of sources to examine the relative abundances of organic molecules as they relate to the physical properties of the source (i.e., temperature, density, dynamics, etc.). The spectra are highly sensitive, with noise levels ≤25 mK at a velocity resolution of ∼0.35 km s{sup −1}. In the initial analysis presented here, column densities and rotational temperatures have been determined for the molecular species that contribute significantly to the spectral line density in this wavelength regime. We present these results and discuss their implications for complex molecule formation in the interstellar medium.

  6. Comparing spatial tuning curves, spectral ripple resolution, and speech perception in cochlear implant users.

    Science.gov (United States)

    Anderson, Elizabeth S; Nelson, David A; Kreft, Heather; Nelson, Peggy B; Oxenham, Andrew J

    2011-07-01

    Spectral ripple discrimination thresholds were measured in 15 cochlear-implant users with broadband (350-5600 Hz) and octave-band noise stimuli. The results were compared with spatial tuning curve (STC) bandwidths previously obtained from the same subjects. Spatial tuning curve bandwidths did not correlate significantly with broadband spectral ripple discrimination thresholds but did correlate significantly with ripple discrimination thresholds when the rippled noise was confined to an octave-wide passband, centered on the STC's probe electrode frequency allocation. Ripple discrimination thresholds were also measured for octave-band stimuli in four contiguous octaves, with center frequencies from 500 Hz to 4000 Hz. Substantial variations in thresholds with center frequency were found in individuals, but no general trends of increasing or decreasing resolution from apex to base were observed in the pooled data. Neither ripple nor STC measures correlated consistently with speech measures in noise and quiet in the sample of subjects in this study. Overall, the results suggest that spectral ripple discrimination measures provide a reasonable measure of spectral resolution that correlates well with more direct, but more time-consuming, measures of spectral resolution, but that such measures do not always provide a clear and robust predictor of performance in speech perception tasks. © 2011 Acoustical Society of America

  7. Sensor Pods: Multi-Resolution Surveys from a Light Aircraft

    Directory of Open Access Journals (Sweden)

    Conor Cahalane

    2017-02-01

    Full Text Available Airborne remote sensing, whether performed from conventional aerial survey platforms such as light aircraft or the more recent Remotely Piloted Airborne Systems (RPAS has the ability to compliment mapping generated using earth-orbiting satellites, particularly for areas that may experience prolonged cloud cover. Traditional aerial platforms are costly but capture spectral resolution imagery over large areas. RPAS are relatively low-cost, and provide very-high resolution imagery but this is limited to small areas. We believe that we are the first group to retrofit these new, low-cost, lightweight sensors in a traditional aircraft. Unlike RPAS surveys which have a limited payload, this is the first time that a method has been designed to operate four distinct RPAS sensors simultaneously—hyperspectral, thermal, hyper, RGB, video. This means that imagery covering a broad range of the spectrum captured during a single survey, through different imaging capture techniques (frame, pushbroom, video can be applied to investigate different multiple aspects of the surrounding environment such as, soil moisture, vegetation vitality, topography or drainage, etc. In this paper, we present the initial results validating our innovative hybrid system adapting dedicated RPAS sensors for a light aircraft sensor pod, thereby providing the benefits of both methodologies. Simultaneous image capture with a Nikon D800E SLR and a series of dedicated RPAS sensors, including a FLIR thermal imager, a four-band multispectral camera and a 100-band hyperspectral imager was enabled by integration in a single sensor pod operating from a Cessna c172. However, to enable accurate sensor fusion for image analysis, each sensor must first be combined in a common vehicle coordinate system and a method for triggering, time-stamping and calculating the position/pose of each sensor at the time of image capture devised. Initial tests were carried out over agricultural regions with

  8. High-Resolution Spectral Measurement of High Temperature CO2 and H2O.

    Science.gov (United States)

    1980-12-01

    a major constituent which critically controls the infrared radiative transfer in the telluric atmosphere. Their absorption bands are distributed over... movement to prevent cracking. Also, the continuous Q = s/) spectrum spectral coverage filament ceramic fiber, brand AB-312 manufactured by resolution the 3M

  9. Very High Spectral Resolution Imaging Spectroscopy: the Fluorescence Explorer (FLEX) Mission

    Science.gov (United States)

    Moreno, Jose F.; Goulas, Yves; Huth, Andreas; Middleton, Elizabeth; Miglietta, Franco; Mohammed, Gina; Nedbal, Ladislav; Rascher, Uwe; Verhoef, Wouter; Drusch, Matthias

    2016-01-01

    The Fluorescence Explorer (FLEX) mission has been recently selected as the 8th Earth Explorer by the European Space Agency (ESA). It will be the first mission specifically designed to measure from space vegetation fluorescence emission, by making use of very high spectral resolution imaging spectroscopy techniques. Vegetation fluorescence is the best proxy to actual vegetation photosynthesis which can be measurable from space, allowing an improved quantification of vegetation carbon assimilation and vegetation stress conditions, thus having key relevance for global mapping of ecosystems dynamics and aspects related with agricultural production and food security. The FLEX mission carries the FLORIS spectrometer, with a spectral resolution in the range of 0.3 nm, and is designed to fly in tandem with Copernicus Sentinel-3, in order to provide all the necessary spectral / angular information to disentangle emitted fluorescence from reflected radiance, and to allow proper interpretation of the observed fluorescence spatial and temporal dynamics.

  10. Comparison of inversion accuracy of soil copper content from vegetation indices under different spectral resolution

    Science.gov (United States)

    Sun, Zhongqing; Shang, Kun; Jia, Lingjun

    2018-03-01

    Remote sensing inversion of heavy metal in vegetation leaves is generally based on the physiological characteristics of vegetation spectrum under heavy metal stress, and empirical models with vegetation indices are established to inverse the heavy metal content of vegetation leaves. However, the research of inversion of heavy metal content in vegetation-covered soil is still rare. In this study, Pulang is chosen as study area. The regression model of a typical heavy metal element, copper (Cu), is established with vegetation indices. We mainly investigate the inversion accuracies of Cu element in vegetation-covered soil by different vegetation indices according to specific spectral resolutions of ASD (Analytical Spectral Device) and Hyperion data. The inversion results of soil copper content in the vegetation-covered area shows a good accuracy, and the vegetation indices under ASD spectral resolution correspond to better results.

  11. CHEMICAL ABUNDANCES IN FIELD RED GIANTS FROM HIGH-RESOLUTION H-BAND SPECTRA USING THE APOGEE SPECTRAL LINELIST

    International Nuclear Information System (INIS)

    Smith, Verne V.; Cunha, Katia; Shetrone, Matthew D.; Meszaros, Szabolcs; Allende Prieto, Carlos; Bizyaev, Dmitry; Garcìa Pèrez, Ana; Majewski, Steven R.; Schiavon, Ricardo; Holtzman, Jon; Johnson, Jennifer A.

    2013-01-01

    High-resolution H-band spectra of five bright field K, M, and MS giants, obtained from the archives of the Kitt Peak National Observatory Fourier transform spectrometer, are analyzed to determine chemical abundances of 16 elements. The abundances were derived via spectrum synthesis using the detailed linelist prepared for the Sloan Digital Sky Survey III Apache Point Galactic Evolution Experiment (APOGEE), which is a high-resolution near-infrared spectroscopic survey to derive detailed chemical abundance distributions and precise radial velocities for 100,000 red giants sampling all Galactic stellar populations. The red giant sample studied here was chosen to probe which chemical elements can be derived reliably from the H-band APOGEE spectral region. These red giants consist of two K-giants (α Boo and μ Leo), two M-giants (β And and δ Oph), and one thermally pulsing asymptotic giant branch (TP-AGB) star of spectral type MS (HD 199799). Measured chemical abundances include the cosmochemically important isotopes 12 C, 13 C, 14 N, and 16 O, along with Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. The K and M giants exhibit the abundance signature of the first dredge-up of CN-cycle material, while the TP-AGB star shows clear evidence of the addition of 12 C synthesized during 4 He-burning thermal pulses and subsequent third dredge-up. A comparison of the abundances derived here with published values for these stars reveals consistent results to ∼0.1 dex. The APOGEE spectral region and linelist is thus well suited for probing both Galactic chemical evolution, as well as internal nucleosynthesis and mixing in populations of red giants via high-resolution spectroscopy.

  12. CHEMICAL ABUNDANCES IN FIELD RED GIANTS FROM HIGH-RESOLUTION H-BAND SPECTRA USING THE APOGEE SPECTRAL LINELIST

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Verne V.; Cunha, Katia [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States); Shetrone, Matthew D. [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Meszaros, Szabolcs; Allende Prieto, Carlos [Instituto d' Astrofisica de Canarias, E-38205, La Laguna, Tenerife (Spain); Bizyaev, Dmitry [Apache Point Observatory, Sunspot, NM 88349 (United States); Garcia Perez, Ana; Majewski, Steven R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Schiavon, Ricardo [Astrophysics Research Institute, Liverpool John Moores University, Liverpool L3 5UX (United Kingdom); Holtzman, Jon [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Johnson, Jennifer A., E-mail: vsmith@noao.edu [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States)

    2013-03-01

    High-resolution H-band spectra of five bright field K, M, and MS giants, obtained from the archives of the Kitt Peak National Observatory Fourier transform spectrometer, are analyzed to determine chemical abundances of 16 elements. The abundances were derived via spectrum synthesis using the detailed linelist prepared for the Sloan Digital Sky Survey III Apache Point Galactic Evolution Experiment (APOGEE), which is a high-resolution near-infrared spectroscopic survey to derive detailed chemical abundance distributions and precise radial velocities for 100,000 red giants sampling all Galactic stellar populations. The red giant sample studied here was chosen to probe which chemical elements can be derived reliably from the H-band APOGEE spectral region. These red giants consist of two K-giants ({alpha} Boo and {mu} Leo), two M-giants ({beta} And and {delta} Oph), and one thermally pulsing asymptotic giant branch (TP-AGB) star of spectral type MS (HD 199799). Measured chemical abundances include the cosmochemically important isotopes {sup 12}C, {sup 13}C, {sup 14}N, and {sup 16}O, along with Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. The K and M giants exhibit the abundance signature of the first dredge-up of CN-cycle material, while the TP-AGB star shows clear evidence of the addition of {sup 12}C synthesized during {sup 4}He-burning thermal pulses and subsequent third dredge-up. A comparison of the abundances derived here with published values for these stars reveals consistent results to {approx}0.1 dex. The APOGEE spectral region and linelist is thus well suited for probing both Galactic chemical evolution, as well as internal nucleosynthesis and mixing in populations of red giants via high-resolution spectroscopy.

  13. 3D high spectral and spatial resolution imaging of ex vivo mouse brain

    International Nuclear Information System (INIS)

    Foxley, Sean; Karczmar, Gregory S.; Domowicz, Miriam; Schwartz, Nancy

    2015-01-01

    Purpose: Widely used MRI methods show brain morphology both in vivo and ex vivo at very high resolution. Many of these methods (e.g., T 2 * -weighted imaging, phase-sensitive imaging, or susceptibility-weighted imaging) are sensitive to local magnetic susceptibility gradients produced by subtle variations in tissue composition. However, the spectral resolution of commonly used methods is limited to maintain reasonable run-time combined with very high spatial resolution. Here, the authors report on data acquisition at increased spectral resolution, with 3-dimensional high spectral and spatial resolution MRI, in order to analyze subtle variations in water proton resonance frequency and lineshape that reflect local anatomy. The resulting information compliments previous studies based on T 2 * and resonance frequency. Methods: The proton free induction decay was sampled at high resolution and Fourier transformed to produce a high-resolution water spectrum for each image voxel in a 3D volume. Data were acquired using a multigradient echo pulse sequence (i.e., echo-planar spectroscopic imaging) with a spatial resolution of 50 × 50 × 70 μm 3 and spectral resolution of 3.5 Hz. Data were analyzed in the spectral domain, and images were produced from the various Fourier components of the water resonance. This allowed precise measurement of local variations in water resonance frequency and lineshape, at the expense of significantly increased run time (16–24 h). Results: High contrast T 2 * -weighted images were produced from the peak of the water resonance (peak height image), revealing a high degree of anatomical detail, specifically in the hippocampus and cerebellum. In images produced from Fourier components of the water resonance at −7.0 Hz from the peak, the contrast between deep white matter tracts and the surrounding tissue is the reverse of the contrast in water peak height images. This indicates the presence of a shoulder in the water resonance that is not

  14. 3D high spectral and spatial resolution imaging of ex vivo mouse brain

    Energy Technology Data Exchange (ETDEWEB)

    Foxley, Sean, E-mail: sean.foxley@ndcn.ox.ac.uk; Karczmar, Gregory S. [Department of Radiology, University of Chicago, Chicago, Illinois 60637 (United States); Domowicz, Miriam [Department of Pediatrics, University of Chicago, Chicago, Illinois 60637 (United States); Schwartz, Nancy [Department of Pediatrics, Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637 (United States)

    2015-03-15

    Purpose: Widely used MRI methods show brain morphology both in vivo and ex vivo at very high resolution. Many of these methods (e.g., T{sub 2}{sup *}-weighted imaging, phase-sensitive imaging, or susceptibility-weighted imaging) are sensitive to local magnetic susceptibility gradients produced by subtle variations in tissue composition. However, the spectral resolution of commonly used methods is limited to maintain reasonable run-time combined with very high spatial resolution. Here, the authors report on data acquisition at increased spectral resolution, with 3-dimensional high spectral and spatial resolution MRI, in order to analyze subtle variations in water proton resonance frequency and lineshape that reflect local anatomy. The resulting information compliments previous studies based on T{sub 2}{sup *} and resonance frequency. Methods: The proton free induction decay was sampled at high resolution and Fourier transformed to produce a high-resolution water spectrum for each image voxel in a 3D volume. Data were acquired using a multigradient echo pulse sequence (i.e., echo-planar spectroscopic imaging) with a spatial resolution of 50 × 50 × 70 μm{sup 3} and spectral resolution of 3.5 Hz. Data were analyzed in the spectral domain, and images were produced from the various Fourier components of the water resonance. This allowed precise measurement of local variations in water resonance frequency and lineshape, at the expense of significantly increased run time (16–24 h). Results: High contrast T{sub 2}{sup *}-weighted images were produced from the peak of the water resonance (peak height image), revealing a high degree of anatomical detail, specifically in the hippocampus and cerebellum. In images produced from Fourier components of the water resonance at −7.0 Hz from the peak, the contrast between deep white matter tracts and the surrounding tissue is the reverse of the contrast in water peak height images. This indicates the presence of a shoulder in

  15. Dwarfs Cooler Than M: The Definition of Spectral Type L Using Discoveries from the 2-Micron All-Sky Survey (2MASS)

    Science.gov (United States)

    Kirkpatrick, J.; Reid, I.; Liebert, J.; Cutri, R.; Nelson, B.; Beichman, C.; Dahn, C.; Monet, D.; Gizis, J.; Skrutskie, M.

    1998-01-01

    Before the 2-Micron All-Sky Survey (2MASS) began, only six objects were known with spectral types later than M9.5 V. In the first 371 sq. deg. of actual 2MASS survey data, we have identified another twenty such objects spectroscopically confirmed using the Low Resolution Imaging Spectrograph (LRIS) at the W.M. Keck Observatory.

  16. X-ray stars observed in LAMOST spectral survey

    Science.gov (United States)

    Lu, Hong-peng; Zhang, Li-yun; Han, Xianming L.; Shi, Jianrong

    2018-05-01

    X-ray stars have been studied since the beginning of X-ray astronomy. Investigating and studying the chromospheric activity from X-ray stellar optical spectra is highly significant in providing insights into stellar magnetic activity. The big data of LAMOST survey provides an opportunity for researching stellar optical spectroscopic properties of X-ray stars. We inferred the physical properties of X-ray stellar sources from the analysis of LAMOST spectra. First, we cross-matched the X-ray stellar catalogue (12254 X-ray stars) from ARXA with LAMOST data release 3 (DR3), and obtained 984 good spectra from 713 X-ray sources. We then visually inspected and assigned spectral type to each spectrum and calculated the equivalent width (EW) of Hα line using the Hammer spectral typing facility. Based on the EW of Hα line, we found 203 spectra of 145 X-ray sources with Hα emission above the continuum. For these spectra we also measured the EWs of Hβ, Hγ, Hδ and Ca ii IRT lines of these spectra. After removing novae, planetary nebulae and OB-type stars, we found there are 127 X-ray late-type stars with Hα line emission. By using our spectra and results from the literature, we found 53 X-ray stars showing Hα variability; these objects are Classical T Tauri stars (CTTs), cataclysmic variables (CVs) or chromospheric activity stars. We also found 18 X-ray stars showing obvious emissions in the Ca ii IRT lines. Of the 18 X-ray stars, 16 are CTTs and 2 are CVs. Finally, we discussed the relationships between the EW of Hα line and X-ray flux.

  17. ANALYZING SPECTRAL CHARACTERISTICS OF SHADOW AREA FROM ADS-40 HIGH RADIOMETRIC RESOLUTION AERIAL IMAGES

    Directory of Open Access Journals (Sweden)

    Y.-T. Hsieh

    2016-06-01

    Full Text Available The shadows in optical remote sensing images are regarded as image nuisances in numerous applications. The classification and interpretation of shadow area in a remote sensing image are a challenge, because of the reduction or total loss of spectral information in those areas. In recent years, airborne multispectral aerial image devices have been developed 12-bit or higher radiometric resolution data, including Leica ADS-40, Intergraph DMC. The increased radiometric resolution of digital imagery provides more radiometric details of potential use in classification or interpretation of land cover of shadow areas. Therefore, the objectives of this study are to analyze the spectral properties of the land cover in the shadow areas by ADS-40 high radiometric resolution aerial images, and to investigate the spectral and vegetation index differences between the various shadow and non-shadow land covers. According to research findings of spectral analysis of ADS-40 image: (i The DN values in shadow area are much lower than in nonshadow area; (ii DN values received from shadowed areas that will also be affected by different land cover, and it shows the possibility of land cover property retrieval as in nonshadow area; (iii The DN values received from shadowed regions decrease in the visible band from short to long wavelengths due to scattering; (iv The shadow area NIR of vegetation category also shows a strong reflection; (v Generally, vegetation indexes (NDVI still have utility to classify the vegetation and non-vegetation in shadow area. The spectral data of high radiometric resolution images (ADS-40 is potential for the extract land cover information of shadow areas.

  18. The HIFI spectral survey of AFGL 2591 (CHESS). II. Summary of the survey

    Science.gov (United States)

    Kaźmierczak-Barthel, M.; van der Tak, F. F. S.; Helmich, F. P.; Chavarría, L.; Wang, K.-S.; Ceccarelli, C.

    2014-07-01

    Aims: This paper presents the richness of submillimeter spectral features in the high-mass star forming region AFGL 2591. Methods: As part of the Chemical Herschel Survey of Star Forming Regions (CHESS) key programme, AFGL 2591 was observed by the Herschel (HIFI) instrument. The spectral survey covered a frequency range from 480 to 1240 GHz as well as single lines from 1267 to 1901 GHz (i.e. CO, HCl, NH3, OH, and [CII]). Rotational and population diagram methods were used to calculate column densities, excitation temperatures, and the emission extents of the observed molecules associated with AFGL 2591. The analysis was supplemented with several lines from ground-based JCMT spectra. Results: From the HIFI spectral survey analysis a total of 32 species were identified (including isotopologues). Although the lines are mostly quite weak (∫TmbdV ~ few K km s-1), 268 emission and 16 absorption lines were found (excluding blends). Molecular column densities range from 6 × 1011 to 1 × 1019 cm-2 and excitation temperatures from 19 to 175 K. Cold (e.g. HCN, H2S, and NH3 with temperatures below 70 K) and warm species (e.g. CH3OH, SO2) in the protostellar envelope can be distinguished. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Appendix A is available in electronic form at http://www.aanda.org

  19. Influence of spectral resolution, spectral range and signal-to-noise ratio of Fourier transform infra-red spectra on identification of high explosive substances

    Science.gov (United States)

    Banas, Krzysztof; Banas, Agnieszka M.; Heussler, Sascha P.; Breese, Mark B. H.

    2018-01-01

    In the contemporary spectroscopy there is a trend to record spectra with the highest possible spectral resolution. This is clearly justified if the spectral features in the spectrum are very narrow (for example infra-red spectra of gas samples). However there is a plethora of samples (in the liquid and especially in the solid form) where there is a natural spectral peak broadening due to collisions and proximity predominately. Additionally there is a number of portable devices (spectrometers) with inherently restricted spectral resolution, spectral range or both, which are extremely useful in some field applications (archaeology, agriculture, food industry, cultural heritage, forensic science). In this paper the investigation of the influence of spectral resolution, spectral range and signal-to-noise ratio on the identification of high explosive substances by applying multivariate statistical methods on the Fourier transform infra-red spectral data sets is studied. All mathematical procedures on spectral data for dimension reduction, clustering and validation were implemented within R open source environment.

  20. Performance characterization of a pressure-tuned wide-angle Michelson interferometric spectral filter for high spectral resolution lidar

    Science.gov (United States)

    Seaman, Shane T.; Cook, Anthony L.; Scola, Salvatore J.; Hostetler, Chris A.; Miller, Ian; Welch, Wayne

    2015-09-01

    High Spectral Resolution Lidar (HSRL) is typically realized using an absorption filter to separate molecular returns from particulate returns. NASA Langley Research Center (LaRC) has designed and built a Pressure-Tuned Wide-Angle Michelson Interferometer (PTWAMI) as an alternate means to separate the two types of atmospheric returns. While absorption filters only work at certain wavelengths and suffer from low photon efficiency due to light absorption, an interferometric spectral filter can be designed for any wavelength and transmits nearly all incident photons. The interferometers developed at LaRC employ an air spacer in one arm, and a solid glass spacer in the other. Field widening is achieved by specific design and selection of the lengths and refractive indices of these two arms. The principal challenge in using such an interferometer as a spectral filter for HSRL aboard aircraft is that variations in glass temperature and air pressure cause changes in the interferometer's optical path difference. Therefore, a tuning mechanism is needed to actively accommodate for these changes. The pressure-tuning mechanism employed here relies on changing the pressure in an enclosed, air-filled arm of the interferometer to change the arm's optical path length. However, tuning using pressure will not adjust for tilt, mirror warpage, or thermally induced wavefront error, so the structural, thermal, and optical behavior of the device must be well understood and optimized in the design and manufacturing process. The PTWAMI has been characterized for particulate transmission ratio, wavefront error, and tilt, and shows acceptable performance for use in an HSRL instrument.

  1. PCA determination of the radiometric noise of high spectral resolution infrared observations from spectral residuals: Application to IASI

    Science.gov (United States)

    Serio, C.; Masiello, G.; Camy-Peyret, C.; Jacquette, E.; Vandermarcq, O.; Bermudo, F.; Coppens, D.; Tobin, D.

    2018-02-01

    The problem of characterizing and estimating the instrumental or radiometric noise of satellite high spectral resolution infrared spectrometers directly from Earth observations is addressed in this paper. An approach has been developed, which relies on the Principal Component Analysis (PCA) with a suitable criterion to select the optimal number of PC scores. Different selection criteria have been set up and analysed, which is based on the estimation theory of Least Squares and/or Maximum Likelihood Principle. The approach is independent of any forward model and/or radiative transfer calculations. The PCA is used to define an orthogonal basis, which, in turn, is used to derive an optimal linear reconstruction of the observations. The residual vector that is the observation vector minus the calculated or reconstructed one is then used to estimate the instrumental noise. It will be shown that the use of the spectral residuals to assess the radiometric instrumental noise leads to efficient estimators, which are largely independent of possible departures of the true noise from that assumed a priori to model the observational covariance matrix. Application to the Infrared Atmospheric Sounder Interferometer (IASI) has been considered. A series of case studies has been set up, which make use of IASI observations. As a major result, the analysis confirms the high stability and radiometric performance of IASI. The approach also proved to be efficient in characterizing noise features due to mechanical micro-vibrations of the beam splitter of the IASI instrument.

  2. Transport survey calculations using the spectral collocation method

    International Nuclear Information System (INIS)

    Painter, S.L.; Lyon, J.F.

    1989-01-01

    A novel transport survey code has been developed and is being used to study the sensitivity of stellarator reactor performance to various transport assumptions. Instead of following one of the usual approaches, the steady-state transport equation are solved in integral form using the spectral collocation method. This approach effectively combine the computational efficiency of global models with the general nature of 1-D solutions. A compact torsatron reactor test case was used to study the convergence properties and flexibility of the new method. The heat transport model combined Shaing's model for ripple-induced neoclassical transport, the Chang-Hinton model for axisymmetric neoclassical transport, and neoalcator scaling for anomalous electron heat flux. Alpha particle heating, radiation losses, classical electron-ion heat flow, and external heating were included. For the test problem, the method exhibited some remarkable convergence properties. As the number of basis functions was increased, the maximum, pointwise error in the integrated power balance decayed exponentially until the numerical noise level as reached. Better than 10% accuracy in the globally-averaged quantities was achieved with only 5 basis functions; better than 1% accuracy was achieved with 10 basis functions. The numerical method was also found to be very general. Extreme temperature gradients at the plasma edge which sometimes arise from the neoclassical models and are difficult to resolve with finite-difference methods were easily resolved. 8 refs., 6 figs

  3. Advancing Atmosphere-Ocean Remote Sensing with Spaceborne High Spectral Resolution Lidar

    Science.gov (United States)

    Hostetler, C. A.; Behrenfeld, M. J.; Chepfer, H.; Hu, Y.; Hair, J. W.; Trepte, C. R.; Winker, D. M.; Ferrare, R. A.; Burton, S. P.; Scarino, A. J.; Powell, K. A.; Michaud, J.

    2016-12-01

    More than 1600 publications employing observations from the CALIOP lidar on CALIPSO testify to the value of spaceborne lidar for aerosol and cloud remote sensing. Recent publications have shown the value of CALIOP data for retrievals of key ocean carbon cycle stocks. In this presentation we focus on the advantages of a more advanced technique, High Spectral Resolution Lidar (HSRL), for aerosol, cloud, and ocean remote sensing. An atmosphere-ocean optimized HSRL achieves greater accuracy over the standard backscatter lidar technique for retrievals of aerosol and cloud extinction and backscatter profiles, provides additional capability to retrieve aerosol and cloud microphysical parameters, and enables vertically-resolved characterization of scattering and absorption properties of suspended and dissolved materials in the ocean. Numerous publications highlight the synergy of coincident CALIOP and passive A-train observations for studies of aerosol-cloud radiative effects and cloud-climate feedback. Less appreciated is the complementarity that would exist between an optimized spaceborne lidar and passive ocean color. An optimized HSRL flown in formation with the Plankton, Aerosol, and ocean Ecosystem (PACE) mission would provide phytoplankton vertical distribution, which is needed for accurately estimating net primary productivity but absent in the PACE ocean color data. The HSRL would also provide data needed to improve atmospheric correction schemes in ocean color retrievals. Because lidar provides measurements both night and day, through tenuous clouds and aerosol layers, and in holes between clouds, the sampling achieved is highly complementary to passive radiometry, providing data in important high latitude regions where ocean color data are sparse or nonexistent. In this presentation we will discuss 1) relevant aerosol, cloud, and ocean retrievals from airborne HSRL field missions; 2) the advantages of an optimized spaceborne HSRL for aerosol, cloud, and ocean

  4. An Interferometric 270--355 GHz Spectral Line Survey of the Red Supergiant VY CMa

    Science.gov (United States)

    Menten, K. M.; Young, K. H.; Patel, N. A.; Gottlieb, C. A.; Thaddeus, P.; McCarthy, M. C.; Gurwell, M. A.; Belloche, A.; Kaminski, T.; Verheyen, L.; Decin, L.; Brunken, S.; Holger, S. P. M.

    2011-05-01

    We have used the Submillimeter Array to image the molecular line emission in the circumstellar envelope of the peculiar red supergiant star VY Canis Majoris over the whole 870 μm atmospheric window. Employing adaptive calibration using the object's continuum emission we achieve high quality one arcsecond resolution imaging of the whole 280--355 GHz range within which we find 211 distinct spectral lines from 33 molecules (including isotopologues) plus 40 unidentified lines. From the distribution of molecules we are obtaining their abundances and isotopologic abundance ratios. Using data for multiple transitions in a number of molecules we are deriving the physical conditions in the circumstellar envelope to reach a picture of the star's chemistry that can be compared with models. Our legacy survey is accompanied by a strong laboratory effort that helps with the identification of possibly newly found molecules traced by unidentified lines. We shall create a publicly accessible database of spectral-line channel-maps of the emission from all the lines detected in the survey.

  5. Validation of a clinical assessment of spectral-ripple resolution for cochlear implant users.

    Science.gov (United States)

    Drennan, Ward R; Anderson, Elizabeth S; Won, Jong Ho; Rubinstein, Jay T

    2014-01-01

    Nonspeech psychophysical tests of spectral resolution, such as the spectral-ripple discrimination task, have been shown to correlate with speech-recognition performance in cochlear implant (CI) users. However, these tests are best suited for use in the research laboratory setting and are impractical for clinical use. A test of spectral resolution that is quicker and could more easily be implemented in the clinical setting has been developed. The objectives of this study were (1) To determine whether this new clinical ripple test would yield individual results equivalent to the longer, adaptive version of the ripple-discrimination test; (2) To evaluate test-retest reliability for the clinical ripple measure; and (3) To examine the relationship between clinical ripple performance and monosyllabic word recognition in quiet for a group of CI listeners. Twenty-eight CI recipients participated in the study. Each subject was tested on both the adaptive and the clinical versions of spectral ripple discrimination, as well as consonant-nucleus-consonant word recognition in quiet. The adaptive version of spectral ripple used a two-up, one-down procedure for determining spectral ripple discrimination threshold. The clinical ripple test used a method of constant stimuli, with trials for each of 12 fixed ripple densities occurring six times in random order. Results from the clinical ripple test (proportion correct) were then compared with ripple-discrimination thresholds (in ripples per octave) from the adaptive test. The clinical ripple test showed strong concurrent validity, evidenced by a good correlation between clinical ripple and adaptive ripple results (r = 0.79), as well as a correlation with word recognition (r = 0.7). Excellent test-retest reliability was also demonstrated with a high test-retest correlation (r = 0.9). The clinical ripple test is a reliable nonlinguistic measure of spectral resolution, optimized for use with CI users in a clinical setting. The test

  6. VALIDATION OF A CLINICAL ASSESSMENT OF SPECTRAL RIPPLE RESOLUTION FOR COCHLEAR-IMPLANT USERS

    Science.gov (United States)

    Drennan, Ward. R.; Anderson, Elizabeth S.; Won, Jong Ho; Rubinstein, Jay T.

    2013-01-01

    Objectives Non-speech psychophysical tests of spectral resolution, such as the spectral-ripple discrimination task, have been shown to correlate with speech recognition performance in cochlear implant (CI) users (Henry et al., 2005; Won et al. 2007, 2011; Drennan et al. 2008; Anderson et al. 2011). However, these tests are best suited for use in the research laboratory setting and are impractical for clinical use. A test of spectral resolution that is quicker and could more easily be implemented in the clinical setting has been developed. The objectives of this study were 1) To determine if this new clinical ripple test would yield individual results equivalent to the longer, adaptive version of the ripple discrimination test; 2) To evaluate test-retest reliability for the clinical ripple measure; and 3) To examine the relationship between clinical ripple performance and monosyllabic word recognition in quiet for a group of CI listeners. Design Twenty-eight CI recipients participated in the study. Each subject was tested on both the adaptive and the clinical versions of spectral ripple discrimination, as well as CNC word recognition in quiet. The adaptive version of spectral ripple employed a 2-up, 1-down procedure for determining spectral ripple discrimination threshold. The clinical ripple test used a method of constant stimuli, with trials for each of 12 fixed ripple densities occurring six times in random order. Results from the clinical ripple test (proportion correct) were then compared to ripple discrimination thresholds (in ripples per octave) from the adaptive test. Results The clinical ripple test showed strong concurrent validity, evidenced by a good correlation between clinical ripple and adaptive ripple results (r=0.79), as well as a correlation with word recognition (r = 0.7). Excellent test-retest reliability was also demonstrated with a high test-retest correlation (r = 0.9). Conclusions The clinical ripple test is a reliable non-linguistic measure

  7. Spectral types for objects in the Kiso survey. IV - Data for 81 stars

    Science.gov (United States)

    Wegner, Gary; Mcmahan, Robert K.

    1988-01-01

    Spectroscopy and spectral types for 81 ultraviolet-excess objects found in the Kiso Schmidt-camera survey are reported. The data were secured with the McGraw-Hill 1.3 m telescope at 8-A resolution covering the wavelength interval 4000 -7200 A using the Mark II spectrograph. Descriptions of the spectra of some of the more peculiar objects found in this sample are given and include 14 sub-dwarfs, 23 definite DA white dwarfs, including a magnetic one, and one DQ whie dwarf, eight quasars and emission-line objects, and a new composite DA + dM system. More spectroscopy of the new cataclysmic variable KUV 01584-0939 and a possibly related object is also described.

  8. Automated road network extraction from high spatial resolution multi-spectral imagery

    Science.gov (United States)

    Zhang, Qiaoping

    For the last three decades, the Geomatics Engineering and Computer Science communities have considered automated road network extraction from remotely-sensed imagery to be a challenging and important research topic. The main objective of this research is to investigate the theory and methodology of automated feature extraction for image-based road database creation, refinement or updating, and to develop a series of algorithms for road network extraction from high resolution multi-spectral imagery. The proposed framework for road network extraction from multi-spectral imagery begins with an image segmentation using the k-means algorithm. This step mainly concerns the exploitation of the spectral information for feature extraction. The road cluster is automatically identified using a fuzzy classifier based on a set of predefined road surface membership functions. These membership functions are established based on the general spectral signature of road pavement materials and the corresponding normalized digital numbers on each multi-spectral band. Shape descriptors of the Angular Texture Signature are defined and used to reduce the misclassifications between roads and other spectrally similar objects (e.g., crop fields, parking lots, and buildings). An iterative and localized Radon transform is developed for the extraction of road centerlines from the classified images. The purpose of the transform is to accurately and completely detect the road centerlines. It is able to find short, long, and even curvilinear lines. The input image is partitioned into a set of subset images called road component images. An iterative Radon transform is locally applied to each road component image. At each iteration, road centerline segments are detected based on an accurate estimation of the line parameters and line widths. Three localization approaches are implemented and compared using qualitative and quantitative methods. Finally, the road centerline segments are grouped into a

  9. The Galah Survey: Classification and Diagnostics with t-SNE Reduction of Spectral Information

    Energy Technology Data Exchange (ETDEWEB)

    Traven, G.; Zwitter, T.; Žerjal, M. [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Matijevič, G. [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Kos, J.; Bland-Hawthorn, J.; De Silva, G.; Sharma, S. [Sydney Institute for Astronomy, School of Physics, A28, The University of Sydney, NSW 2006 (Australia); Asplund, M.; Freeman, K.; Lin, J.; Da Costa, G.; Duong, L. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Casey, A. R. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Martell, S. L. [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Schlesinger, K. J. [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611 (Australia); Simpson, J. D. [Australian Astronomical Observatory, North Ryde, NSW 2113 (Australia); Zucker, D. B. [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Anguiano, B. [Department of Physics and Astronomy, Macquarie University, North Ryde, NSW 2109 (Australia); Horner, J., E-mail: gregor.traven@fmf.uni-lj.si [Computational Engineering and Science Research Centre, University of Southern Queensland, Towoomba QLD 4350 (Australia); and others

    2017-02-01

    Galah is an ongoing high-resolution spectroscopic survey with the goal of disentangling the formation history of the Milky Way using the fossil remnants of disrupted star formation sites that are now dispersed around the Galaxy. It is targeting a randomly selected magnitude-limited ( V ≤ 14) sample of stars, with the goal of observing one million objects. To date, 300,000 spectra have been obtained. Not all of them are correctly processed by parameter estimation pipelines, and we need to know about them. We present a semi-automated classification scheme that identifies different types of peculiar spectral morphologies in an effort to discover and flag potentially problematic spectra and thus help to preserve the integrity of the survey results. To this end, we employ the recently developed dimensionality reduction technique t-SNE ( t -distributed stochastic neighbor embedding), which enables us to represent the complex spectral morphology in a two-dimensional projection map while still preserving the properties of the local neighborhoods of spectra. We find that the majority (178,483) of the 209,533 Galah spectra considered in this study represents normal single stars, whereas 31,050 peculiar and problematic spectra with very diverse spectral features pertaining to 28,579 stars are distributed into 10 classification categories: hot stars, cool metal-poor giants, molecular absorption bands, binary stars, H α /H β emission, H α /H β emission superimposed on absorption, H α /H β P-Cygni, H α /H β inverted P-Cygni, lithium absorption, and problematic. Classified spectra with supplementary information are presented in the catalog, indicating candidates for follow-up observations and population studies of the short-lived phases of stellar evolution.

  10. The Combined ASTER MODIS Emissivity over Land (CAMEL Part 1: Methodology and High Spectral Resolution Application

    Directory of Open Access Journals (Sweden)

    E. Eva Borbas

    2018-04-01

    Full Text Available As part of a National Aeronautics and Space Administration (NASA MEaSUREs (Making Earth System Data Records for Use in Research Environments Land Surface Temperature and Emissivity project, the Space Science and Engineering Center (UW-Madison and the NASA Jet Propulsion Laboratory (JPL developed a global monthly mean emissivity Earth System Data Record (ESDR. This new Combined ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer and MODIS (Moderate Resolution Imaging Spectroradiometer Emissivity over Land (CAMEL ESDR was produced by merging two current state-of-the-art emissivity datasets: the UW-Madison MODIS Infrared emissivity dataset (UW BF and the JPL ASTER Global Emissivity Dataset Version 4 (GEDv4. The dataset includes monthly global records of emissivity and related uncertainties at 13 hinge points between 3.6–14.3 µm, as well as principal component analysis (PCA coefficients at 5-km resolution for the years 2000 through 2016. A high spectral resolution (HSR algorithm is provided for HSR applications. This paper describes the 13 hinge-points combination methodology and the high spectral resolutions algorithm, as well as reports the current status of the dataset.

  11. High spectral resolution studies of gamma ray bursts on new missions

    International Nuclear Information System (INIS)

    Desai, U. D.; Acuna, M. H.; Cline, T. L.; Dennis, B. R.; Orwig, L. E.; Trombka, J. I.; Starr, R. D.

    1996-01-01

    Two new missions will be launched in 1996 and 1997, each carrying X-ray and gamma ray detectors capable of high spectral resolution at room temperature. The Argentine Satelite de Aplicaciones Cientificas (SAC-B) and the Small Spacecraft Technology Initiative (SSTI) Clark missions will each carry several arrays of X-ray detectors primarily intended for the study of solar flares and gamma-ray bursts. Arrays of small (1 cm 2 ) cadmium zinc telluride (CZT) units will provide x-ray measurements in the 10 to 80 keV range with an energy resolution of ≅6 keV. Arrays of both silicon avalanche photodiodes (APD) and P-intrinsic-N (PIN) photodiodes (for the SAC-B mission only) will provide energy coverage from 2-25 keV with ≅1 keV resolution. For SAC-B, higher energy spectral data covering the 30-300 keV energy range will be provided by CsI(Tl) scintillators coupled to silicon APDs, resulting in similar resolution but greater simplicity relative to conventional CsI/PMT systems. Because of problems with the Pegasus launch vehicle, the launch of SAC-B has been delayed until 1997. The launch of the SSTI Clark mission is scheduled for June 1996

  12. High Spectral Resolution Lidar Based on a Potassium Faraday Dispersive Filter for Daytime Temperature Measurement

    Directory of Open Access Journals (Sweden)

    Abo Makoto

    2016-01-01

    Full Text Available In this paper, a new high-spectral-resolution lidar technique is proposed for measuring the profiles of atmospheric temperature in daytime. Based on the theory of high resolution Rayleigh scattering, the feasibility and advantages of using potassium (K Faraday dispersive optical filters as blocking filters for measuring atmospheric temperature are demonstrated with a numerical simulation. It was found that temperature profiles could be measured within 1K error for the height of 9 km with a 500 m range resolution in 60 min by using laser pulses with 1mJ/pulse and 1 kHz, and a 50 cm diameter telescope. Furthermore, we are developing compact pulsed laser system for temperature lidar transmitter.

  13. THE ALMA SPECTROSCOPIC SURVEY IN THE HUBBLE ULTRA DEEP FIELD: IMPLICATIONS FOR SPECTRAL LINE INTENSITY MAPPING AT MILLIMETER WAVELENGTHS AND CMB SPECTRAL DISTORTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Carilli, C. L.; Walter, F. [National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801 (United States); Chluba, J. [Jodrell Bank Centre for Astrophysics, University of Manchester, Oxford Road, M13 9PL (United Kingdom); Decarli, R. [Max-Planck Institute for Astronomy, D-69117 Heidelberg (Germany); Aravena, M. [Nucleo de Astronomia, Facultad de Ingenieria, Universidad Diego Portales, Av. Ejercito 441, Santiago (Chile); Wagg, J. [Square Kilometre Array Organisation, Lower Withington, Cheshire (United Kingdom); Popping, G. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748, Garching (Germany); Cortes, P. [Joint ALMA Observatory—ESO, Av. Alonso de Cordova, 3104, Santiago (Chile); Hodge, J. [Leiden Observatory, Leiden University, Niels Bohrweg 2, NL2333 RA Leiden (Netherlands); Weiss, A. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Bertoldi, F. [Argelander Institute for Astronomy, University of Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany); Riechers, D., E-mail: ccarilli@aoc.nrao.edu [Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States)

    2016-12-10

    We present direct estimates of the mean sky brightness temperature in observing bands around 99 and 242 GHz due to line emission from distant galaxies. These values are calculated from the summed line emission observed in a blind, deep survey for spectral line emission from high redshift galaxies using ALMA (the ALMA spectral deep field observations “ASPECS” survey). In the 99 GHz band, the mean brightness will be dominated by rotational transitions of CO from intermediate and high redshift galaxies. In the 242 GHz band, the emission could be a combination of higher order CO lines, and possibly [C ii] 158 μ m line emission from very high redshift galaxies ( z  ∼ 6–7). The mean line surface brightness is a quantity that is relevant to measurements of spectral distortions of the cosmic microwave background, and as a potential tool for studying large-scale structures in the early universe using intensity mapping. While the cosmic volume and the number of detections are admittedly small, this pilot survey provides a direct measure of the mean line surface brightness, independent of conversion factors, excitation, or other galaxy formation model assumptions. The mean surface brightness in the 99 GHZ band is: T{sub B}  = 0.94 ± 0.09 μ K. In the 242 GHz band, the mean brightness is: T{sub B}  = 0.55 ± 0.033 μ K. These should be interpreted as lower limits on the average sky signal, since we only include lines detected individually in the blind survey, while in a low resolution intensity mapping experiment, there will also be the summed contribution from lower luminosity galaxies that cannot be detected individually in the current blind survey.

  14. THE GBT 67–93.6 GHz SPECTRAL LINE SURVEY OF ORION-KL

    International Nuclear Information System (INIS)

    Frayer, D. T.; Maddalena, Ronald J.; Meijer, M.; Hough, L.; White, S.; Norrod, R.; Watts, G.; Stennes, M.; Simon, R.; Woody, D.; Whitehead, M.; Ford, P.; Mello, M.; Bloss, M.; Srikanth, S.; Pospieszalski, M.; Bryerton, E.

    2015-01-01

    We present a 67–93.6 GHz spectral line survey of Orion-KL with the new 4 mm Receiver on the Green Bank Telescope (GBT). The survey reaches unprecedented depths and covers the low-frequency end of the 3 mm atmospheric window which has been relatively unexplored previously. The entire spectral-line survey is published electronically for general use by the astronomical community. The calibration and performance of the 4 mm Receiver on the GBT is also summarized

  15. Spectrally Resolved and Functional Super-resolution Microscopy via Ultrahigh-Throughput Single-Molecule Spectroscopy.

    Science.gov (United States)

    Yan, Rui; Moon, Seonah; Kenny, Samuel J; Xu, Ke

    2018-03-20

    As an elegant integration of the spatial and temporal dimensions of single-molecule fluorescence, single-molecule localization microscopy (SMLM) overcomes the diffraction-limited resolution barrier of optical microscopy by localizing single molecules that stochastically switch between fluorescent and dark states over time. While this type of super-resolution microscopy (SRM) technique readily achieves remarkable spatial resolutions of ∼10 nm, it typically provides no spectral information. Meanwhile, current scanning-based single-location approaches for mapping the positions and spectra of single molecules are limited by low throughput and are difficult to apply to densely labeled (bio)samples. In this Account, we summarize the rationale, design, and results of our recent efforts toward the integration of the spectral dimension of single-molecule fluorescence with SMLM to achieve spectrally resolved SMLM (SR-SMLM) and functional SRM ( f-SRM). By developing a wide-field scheme for spectral measurement and implementing single-molecule fluorescence on-off switching typical of SMLM, we first showed that in densely labeled (bio)samples it is possible to record the fluorescence spectra and positions of millions of single molecules synchronously within minutes, giving rise to ultrahigh-throughput single-molecule spectroscopy and SR-SMLM. This allowed us to first show statistically that for many dyes, single molecules of the same species exhibit near identical emission in fixed cells. This narrow distribution of emission wavelengths, which contrasts markedly with previous results at solid surfaces, allowed us to unambiguously identify single molecules of spectrally similar dyes. Crosstalk-free, multiplexed SRM was thus achieved for four dyes that were merely 10 nm apart in emission spectrum, with the three-dimensional SRM images of all four dyes being automatically aligned within one image channel. The ability to incorporate single-molecule fluorescence measurement with

  16. Wide-field Spatio-Spectral Interferometry: Bringing High Resolution to the Far- Infrared

    Science.gov (United States)

    Leisawitx, David

    Wide-field spatio-spectral interferometry combines spatial and spectral interferometric data to provide integral field spectroscopic information over a wide field of view. This technology breaks through a mission cost barrier that stands in the way of resolving spatially and measuring spectroscopically at far-infrared wavelengths objects that will lead to a deep understanding of planetary system and galaxy formation processes. A space-based far-IR interferometer will combine Spitzer s superb sensitivity with a two order of magnitude gain in angular resolution, and with spectral resolution in the thousands. With the possible exception of detector technology, which is advancing with support from other research programs, the greatest challenge for far-IR interferometry is to demonstrate that the interferometer will actually produce the images and spectra needed to satisfy mission science requirements. With past APRA support, our team has already developed the highly specialized hardware testbed, image projector, computational model, and image construction software required for the proposed effort, and we have access to an ideal test facility.

  17. Optimisation of chromatographic resolution using objective functions including both time and spectral information.

    Science.gov (United States)

    Torres-Lapasió, J R; Pous-Torres, S; Ortiz-Bolsico, C; García-Alvarez-Coque, M C

    2015-01-16

    The optimisation of the resolution in high-performance liquid chromatography is traditionally performed attending only to the time information. However, even in the optimal conditions, some peak pairs may remain unresolved. Such incomplete resolution can be still accomplished by deconvolution, which can be carried out with more guarantees of success by including spectral information. In this work, two-way chromatographic objective functions (COFs) that incorporate both time and spectral information were tested, based on the peak purity (analyte peak fraction free of overlapping) and the multivariate selectivity (figure of merit derived from the net analyte signal) concepts. These COFs are sensitive to situations where the components that coelute in a mixture show some spectral differences. Therefore, they are useful to find out experimental conditions where the spectrochromatograms can be recovered by deconvolution. Two-way multivariate selectivity yielded the best performance and was applied to the separation using diode-array detection of a mixture of 25 phenolic compounds, which remained unresolved in the chromatographic order using linear and multi-linear gradients of acetonitrile-water. Peak deconvolution was carried out using the combination of orthogonal projection approach and alternating least squares. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Spectral Resolution-linked Bias in Transit Spectroscopy of Extrasolar Planets

    Science.gov (United States)

    Deming, Drake; Sheppard, Kyle

    2017-05-01

    We re-visit the principles of transmission spectroscopy for transiting extrasolar planets, focusing on the overlap between the planetary spectrum and the illuminating stellar spectrum. Virtually all current models of exoplanetary transmission spectra utilize an approximation that is inaccurate when the spectrum of the illuminating star has a complex line structure, such as molecular bands in M-dwarf spectra. In those cases, it is desirable to model the observations using a coupled stellar-planetary radiative transfer model calculated at high spectral resolving power, followed by convolution to the observed resolution. Not consistently accounting for overlap of stellar M-dwarf and planetary lines at high spectral resolution can bias the modeled amplitude of the exoplanetary transmission spectrum, producing modeled absorption that is too strong. We illustrate this bias using the exoplanet TRAPPIST-1b, as observed using Hubble Space Telescope/WFC3. The bias in this case is about 250 ppm, 12% of the modeled transit absorption. Transit spectroscopy using JWST will have access to longer wavelengths where the water bands are intrinsically stronger, and the observed signal-to-noise ratios will be higher than currently possible. We therefore expect that this resolution-linked bias will be especially important for future JWST observations of TESS-discovered super-Earths and mini-Neptunes transiting M-dwarfs.

  19. Spectral Resolution-linked Bias in Transit Spectroscopy of Extrasolar Planets

    Energy Technology Data Exchange (ETDEWEB)

    Deming, Drake; Sheppard, Kyle [Department of Astronomy, University of Maryland at College Park, College Park, MD 20742 (United States)

    2017-05-20

    We re-visit the principles of transmission spectroscopy for transiting extrasolar planets, focusing on the overlap between the planetary spectrum and the illuminating stellar spectrum. Virtually all current models of exoplanetary transmission spectra utilize an approximation that is inaccurate when the spectrum of the illuminating star has a complex line structure, such as molecular bands in M-dwarf spectra. In those cases, it is desirable to model the observations using a coupled stellar–planetary radiative transfer model calculated at high spectral resolving power, followed by convolution to the observed resolution. Not consistently accounting for overlap of stellar M-dwarf and planetary lines at high spectral resolution can bias the modeled amplitude of the exoplanetary transmission spectrum, producing modeled absorption that is too strong. We illustrate this bias using the exoplanet TRAPPIST-1b, as observed using Hubble Space Telescope /WFC3. The bias in this case is about 250 ppm, 12% of the modeled transit absorption. Transit spectroscopy using JWST will have access to longer wavelengths where the water bands are intrinsically stronger, and the observed signal-to-noise ratios will be higher than currently possible. We therefore expect that this resolution-linked bias will be especially important for future JWST observations of TESS-discovered super-Earths and mini-Neptunes transiting M-dwarfs.

  20. Spectral Resolution-linked Bias in Transit Spectroscopy of Extrasolar Planets

    International Nuclear Information System (INIS)

    Deming, Drake; Sheppard, Kyle

    2017-01-01

    We re-visit the principles of transmission spectroscopy for transiting extrasolar planets, focusing on the overlap between the planetary spectrum and the illuminating stellar spectrum. Virtually all current models of exoplanetary transmission spectra utilize an approximation that is inaccurate when the spectrum of the illuminating star has a complex line structure, such as molecular bands in M-dwarf spectra. In those cases, it is desirable to model the observations using a coupled stellar–planetary radiative transfer model calculated at high spectral resolving power, followed by convolution to the observed resolution. Not consistently accounting for overlap of stellar M-dwarf and planetary lines at high spectral resolution can bias the modeled amplitude of the exoplanetary transmission spectrum, producing modeled absorption that is too strong. We illustrate this bias using the exoplanet TRAPPIST-1b, as observed using Hubble Space Telescope /WFC3. The bias in this case is about 250 ppm, 12% of the modeled transit absorption. Transit spectroscopy using JWST will have access to longer wavelengths where the water bands are intrinsically stronger, and the observed signal-to-noise ratios will be higher than currently possible. We therefore expect that this resolution-linked bias will be especially important for future JWST observations of TESS-discovered super-Earths and mini-Neptunes transiting M-dwarfs.

  1. Improved mid infrared detector for high spectral or spatial resolution and synchrotron radiation use

    Energy Technology Data Exchange (ETDEWEB)

    Faye, Mbaye; Bordessoule, Michel; Kanouté, Brahim; Brubach, Jean-Blaise; Roy, Pascale [Synchrotron SOLEIL, L’Orme des Merisiers, F-91192 Gif-sur-Yvette (France); Manceron, Laurent [Synchrotron SOLEIL, L’Orme des Merisiers, F-91192 Gif-sur-Yvette (France); Laboratoire MONARIS, CNRS-Université Pierre et Marie Curie, UMR 8233, 4 Place Jussieu, F-75252 Paris Cedex (France)

    2016-06-15

    When using bright, small effective size sources, such as synchrotron radiation light beam, for broadband spectroscopy at spectral or spatial high resolution for mid-IR FTIR measurements, a marked detectivity improvement can be achieved by setting up a device matching the detector optical étendue to that of the source. Further improvement can be achieved by reducing the background unmodulated flux and other intrinsic noise sources using a lower temperature cryogen, such as liquid helium. By the combined use of cooled apertures, cold reimaging optics, filters and adapted detector polarization, and preamplification electronics, the sensitivity of a HgCdTe photoconductive IR detector can be improved by a significant factor with respect to standard commercial devices (more than one order of magnitude on average over 6–20 μm region) and the usable spectral range extended to longer wavelengths. The performances of such an optimized detector developed on the AILES Beamline at SOLEIL are presented here.

  2. Spectral resolution enhancement of Fourier-transform spectrometer based on orthogonal shear interference using Wollaston prism

    Science.gov (United States)

    Cong, Lin-xiao; Huang, Min; Cai, Qi-sheng

    2017-10-01

    In this paper, a multi-line interferogram stitching method based on orthogonal shear using the Wollaston prism(WP) was proposed with a 2D projection interferogram recorded through the rotation of CCD, making the spectral resolution of Fourier-Transform spectrometer(FTS) of a limited spatial size increase by at least three times. The fringes on multi-lines were linked with the pixels of equal optical path difference (OPD). Ideally, the error of sampled phase within one pixel was less than half the wavelength, ensuring consecutive values in the over-sampled dimension while aliasing in another. In the simulation, with the calibration of 1.064μm, spectral lines at 1.31μm and 1.56μm of equal intensity were tested and observed. The result showed a bias of 0.13% at 1.31μm and 1.15% at 1.56μm in amplitude, and the FWHM at 1.31μm reduced from 25nm to 8nm after the sample points increased from 320 to 960. In the comparison of reflectance spectrum of carnauba wax within near infrared(NIR) band, the absorption peak at 1.2μm was more obvious and zoom of the band 1.38 1.43μm closer to the reference, although some fluctuation was in the short-wavelength region arousing the spectral crosstalk. In conclusion, with orthogonal shear based on the rotation of the CCD relative to the axis of WP, the spectral resolution of static FTS was enhanced by the projection of fringes to the grid coordinates and stitching the interferograms into a larger OPD, which showed the advantages of cost and miniaturization in the space-constrained NIR applications.

  3. VLA-ANGST: A HIGH-RESOLUTION H I SURVEY OF NEARBY DWARF GALAXIES

    International Nuclear Information System (INIS)

    Ott, Jürgen; Stilp, Adrienne M.; Dalcanton, Julianne J.; Warren, Steven R.; Skillman, Evan D.; Walter, Fabian; De Blok, W. J. G.; Koribalski, Bärbel; West, Andrew A.

    2012-01-01

    We present the 'Very Large Array survey of Advanced Camera for Surveys Nearby Galaxy Survey Treasury galaxies (VLA-ANGST)'. VLA-ANGST is a National Radio Astronomy Observatory Large Program consisting of high spectral (0.6-2.6 km s –1 ) and spatial (∼6'') resolution observations of neutral, atomic hydrogen (H I) emission toward 35 nearby dwarf galaxies from the ANGST survey. ANGST is a systematic Hubble Space Telescope survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D ∼ –1 for the majority of the galaxies). The VLA-ANGST data products are made publicly available through a dedicated Web site (https://science.nrao.edu/science/surveys/vla-angst). With available star formation histories from resolved stellar populations and lower resolution ancillary observations from the far-infrared to the ultraviolet, VLA-ANGST will enable detailed studies of the relationship between the ISM and star formation in dwarf galaxies on a ∼100 pc scale.

  4. Pre-physical treatment: an important procedure to improve spectral resolution in polymers microstructure studies using 13C solution NMR

    International Nuclear Information System (INIS)

    Pedroza, Oscar J.O.; Tavares, Maria I.B.

    2004-01-01

    Changes in physical properties of polymeric materials can be evaluated from their microstructures, which can be investigated using solution carbon-13 nuclear magnetic resonance (NMR). In this type of study spectral resolution is very important, which obviously depend on the sample and solvent. A pre physical treatment allows for an improvement in the spectral resolution. Consequently, more information on chain linking can be obtained, thus facilitating the determination of the stereo sequences. (author)

  5. High-resolution spectral analysis of light from neutral beams and ion source plasmas

    International Nuclear Information System (INIS)

    McNeill, D.H.; Kim, J.

    1980-05-01

    The spectral distributions of Balmer alpha emission from 7- and 22-cm-diam neutral hydrogen beams have been measured with a Fabry-Perot interferometer to obtain information on the beam energy, divergence, and species composition. Results of these measurements are compared with other data on the beam properties to evaluate high-resolution spectroscopy as a beam diagnostic technique. Measurements on ion source plasmas and on beam-produced background plasmas yield average neutral atom energies of approximately 0.3 and 2.5 eV, respectively

  6. A New High-Resolution Spectral Approach to Noninvasively Evaluate Wall Deformations in Arteries

    Directory of Open Access Journals (Sweden)

    Ivonne Bazan

    2014-01-01

    Full Text Available By locally measuring changes on arterial wall thickness as a function of pressure, the related Young modulus can be evaluated. This physical magnitude has shown to be an important predictive factor for cardiovascular diseases. For evaluating those changes, imaging segmentation or time correlations of ultrasonic echoes, coming from wall interfaces, are usually employed. In this paper, an alternative low-cost technique is proposed to locally evaluate variations on arterial walls, which are dynamically measured with an improved high-resolution calculation of power spectral densities in echo-traces of the wall interfaces, by using a parametric autoregressive processing. Certain wall deformations are finely detected by evaluating the echoes overtones peaks with power spectral estimations that implement Burg and Yule Walker algorithms. Results of this spectral approach are compared with a classical cross-correlation operator, in a tube phantom and “in vitro” carotid tissue. A circulating loop, mimicking heart periods and blood pressure changes, is employed to dynamically inspect each sample with a broadband ultrasonic probe, acquiring multiple A-Scans which are windowed to isolate echo-traces packets coming from distinct walls. Then the new technique and cross-correlation operator are applied to evaluate changing parietal deformations from the detection of displacements registered on the wall faces under periodic regime.

  7. A New High-Resolution Spectral Approach to Noninvasively Evaluate Wall Deformations in Arteries

    Science.gov (United States)

    Bazan, Ivonne; Negreira, Carlos; Ramos, Antonio; Brum, Javier; Ramirez, Alfredo

    2014-01-01

    By locally measuring changes on arterial wall thickness as a function of pressure, the related Young modulus can be evaluated. This physical magnitude has shown to be an important predictive factor for cardiovascular diseases. For evaluating those changes, imaging segmentation or time correlations of ultrasonic echoes, coming from wall interfaces, are usually employed. In this paper, an alternative low-cost technique is proposed to locally evaluate variations on arterial walls, which are dynamically measured with an improved high-resolution calculation of power spectral densities in echo-traces of the wall interfaces, by using a parametric autoregressive processing. Certain wall deformations are finely detected by evaluating the echoes overtones peaks with power spectral estimations that implement Burg and Yule Walker algorithms. Results of this spectral approach are compared with a classical cross-correlation operator, in a tube phantom and “in vitro” carotid tissue. A circulating loop, mimicking heart periods and blood pressure changes, is employed to dynamically inspect each sample with a broadband ultrasonic probe, acquiring multiple A-Scans which are windowed to isolate echo-traces packets coming from distinct walls. Then the new technique and cross-correlation operator are applied to evaluate changing parietal deformations from the detection of displacements registered on the wall faces under periodic regime. PMID:24688596

  8. System analysis of a tilted field-widened Michelson interferometer for high spectral resolution lidar.

    Science.gov (United States)

    Liu, Dong; Hostetler, Chris; Miller, Ian; Cook, Anthony; Hair, Johnathan

    2012-01-16

    High spectral resolution lidars (HSRLs) have shown great value in aircraft aerosol remote sensing application and are planned for future satellite missions. A compact, robust, quasi-monolithic tilted field-widened Michelson interferometer is being developed as the spectral discrimination filter for an second-generation HSRL(HSRL-2) at NASA Langley Research Center. The Michelson interferometer consists of a cubic beam splitter, a solid arm and an air arm. Piezo stacks connect the air arm mirror to the body of the interferometer and can tune the interferometer within a small range. The whole interferometer is tilted so that the standard Michelson output and the reflected complementary output can both be obtained. In this paper, the transmission ratio is proposed to evaluate the performance of the spectral filter for HSRL. The transmission ratios over different types of system imperfections, such as cumulative wavefront error, locking error, reflectance of the beam splitter and anti-reflection coatings, system tilt, and depolarization angle are analyzed. The requirements of each imperfection for good interferometer performance are obtained.

  9. Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains Central Facility

    Energy Technology Data Exchange (ETDEWEB)

    McFarlane, Sally A.; Gaustad, Krista L.; Mlawer, Eli J.; Long, Charles N.; Delamere, Jennifer

    2011-09-01

    We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM) facility at the Southern Great Plains (SGP) site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs), four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated) can be identified. A normalized difference vegetation index (NDVI) is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs) and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.

  10. Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains central facility

    Science.gov (United States)

    McFarlane, S. A.; Gaustad, K. L.; Mlawer, E. J.; Long, C. N.; Delamere, J.

    2011-09-01

    We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM) facility at the Southern Great Plains (SGP) site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs), four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated) can be identified. A normalized difference vegetation index (NDVI) is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs) and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.

  11. A HIGH-RESOLUTION, MULTI-EPOCH SPECTRAL ATLAS OF PECULIAR STARS INCLUDING RAVE, GAIA , AND HERMES WAVELENGTH RANGES

    International Nuclear Information System (INIS)

    Tomasella, Lina; Munari, Ulisse; Zwitter, Tomaz

    2010-01-01

    We present an Echelle+CCD, high signal-to-noise ratio, high-resolution (R = 20,000) spectroscopic atlas of 108 well-known objects representative of the most common types of peculiar and variable stars. The wavelength interval extends from 4600 to 9400 A and includes the RAVE, Gaia, and HERMES wavelength ranges. Multi-epoch spectra are provided for the majority of the observed stars. A total of 425 spectra of peculiar stars, which were collected during 56 observing nights between 1998 November and 2002 August, are presented. The spectra are given in FITS format and heliocentric wavelengths, with accurate subtraction of both the sky background and the scattered light. Auxiliary material useful for custom applications (telluric dividers, spectrophotometric stars, flat-field tracings) is also provided. The atlas aims to provide a homogeneous database of the spectral appearance of stellar peculiarities, a tool useful both for classification purposes and inter-comparison studies. It could also serve in the planning and development of automated classification algorithms designed for RAVE, Gaia, HERMES, and other large-scale spectral surveys. The spectrum of XX Oph is discussed in some detail as an example of the content of the present atlas.

  12. Mapping plastic greenhouse with medium spatial resolution satellite data: Development of a new spectral index

    Science.gov (United States)

    Yang, Dedi; Chen, Jin; Zhou, Yuan; Chen, Xiang; Chen, Xuehong; Cao, Xin

    2017-06-01

    Plastic greenhouses (PGs) are an important agriculture development technique to protect and control the growing environment for food crops. The extensive use of PGs can change the agriculture landscape and affects the local environment. Accurately mapping and estimating the coverage of PGs is a necessity to the strategic planning of modern agriculture. Unfortunately, PG mapping over large areas is methodologically challenging, as the medium spatial resolution satellite imagery (such as Landsat data) used for analysis lacks spatial details and spectral variations. To fill the gap, the paper proposes a new plastic greenhouse index (PGI) based on the spectral, sensitivity, and separability analysis of PGs using medium spatial resolution images. In the context of the Landsat Enhanced Thematic Mapper Plus (ETM+) imagery, the paper examines the effectiveness and capability of the proposed PGI. The results indicate that PGs in Landsat ETM+ image can be successfully detected by the PGI if the PG fraction is greater than 12% in a mixed pixel. A kappa coefficient of 0.83 and overall accuracy of 91.2% were achieved when applying the proposed PGI in the case of Weifang District, Shandong, China. These results show that the proposed index can be applied to identifying transparent PGs in atmospheric corrected Landsat image and has the potential for the digital mapping of plastic greenhouse coverage over a large area.

  13. [The radial velocity measurement accuracy of different spectral type low resolution stellar spectra at different signal-to-noise ratio].

    Science.gov (United States)

    Wang, Feng-Fei; Luo, A-Li; Zhao, Yong-Heng

    2014-02-01

    The radial velocity of the star is very important for the study of the dynamics structure and chemistry evolution of the Milky Way, is also an useful tool for looking for variable or special objects. In the present work, we focus on calculating the radial velocity of different spectral types of low-resolution stellar spectra by adopting a template matching method, so as to provide effective and reliable reference to the different aspects of scientific research We choose high signal-to-noise ratio (SNR) spectra of different spectral type stellar from the Sloan Digital Sky Survey (SDSS), and add different noise to simulate the stellar spectra with different SNR. Then we obtain theradial velocity measurement accuracy of different spectral type stellar spectra at different SNR by employing a template matching method. Meanwhile, the radial velocity measurement accuracy of white dwarf stars is analyzed as well. We concluded that the accuracy of radial velocity measurements of early-type stars is much higher than late-type ones. For example, the 1-sigma standard error of radial velocity measurements of A-type stars is 5-8 times as large as K-type and M-type stars. We discuss the reason and suggest that the very narrow lines of late-type stars ensure the accuracy of measurement of radial velocities, while the early-type stars with very wide Balmer lines, such as A-type stars, become sensitive to noise and obtain low accuracy of radial velocities. For the spectra of white dwarfs stars, the standard error of radial velocity measurement could be over 50 km x s(-1) because of their extremely wide Balmer lines. The above conclusion will provide a good reference for stellar scientific study.

  14. Geo-oculus: high resolution multi-spectral earth imaging mission from geostationary orbit

    Science.gov (United States)

    Vaillon, L.; Schull, U.; Knigge, T.; Bevillon, C.

    2017-11-01

    Geo-Oculus is a GEO-based Earth observation mission studied by Astrium for ESA in 2008-2009 to complement the Sentinel missions, the space component of the GMES (Global Monitoring for Environment & Security). Indeed Earth imaging from geostationary orbit offers new functionalities not covered by existing LEO observation missions, like real-time monitoring and fast revisit capability of any location within the huge area in visibility of the satellite. This high revisit capability is exploited by the Meteosat meteorogical satellites, but with a spatial resolution (500 m nadir for the third generation) far from most of GMES needs (10 to 100 m). To reach such ground resolution from GEO orbit with adequate image quality, large aperture instruments (> 1 m) and high pointing stability (challenges of such missions. To address the requirements from the GMES user community, the Geo-Oculus mission is a combination of routine observations (daily systematic coverage of European coastal waters) with "on-demand" observation for event monitoring (e.g. disasters, fires and oil slicks). The instrument is a large aperture imaging telescope (1.5 m diameter) offering a nadir spatial sampling of 10.5 m (21 m worst case over Europe, below 52.5°N) in a PAN visible channel used for disaster monitoring. The 22 multi-spectral channels have resolutions over Europe ranging from 40 m in UV/VNIR (0.3 to 1 μm) to 750 m in TIR (10-12 μm).

  15. A method of incident angle estimation for high resolution spectral recovery in filter-array-based spectrometers

    Science.gov (United States)

    Kim, Cheolsun; Lee, Woong-Bi; Ju, Gun Wu; Cho, Jeonghoon; Kim, Seongmin; Oh, Jinkyung; Lim, Dongsung; Lee, Yong Tak; Lee, Heung-No

    2017-02-01

    In recent years, there has been an increasing interest in miniature spectrometers for research and development. Especially, filter-array-based spectrometers have advantages of low cost and portability, and can be applied in various fields such as biology, chemistry and food industry. Miniaturization in optical filters causes degradation of spectral resolution due to limitations on spectral responses and the number of filters. Nowadays, many studies have been reported that the filter-array-based spectrometers have achieved resolution improvements by using digital signal processing (DSP) techniques. The performance of the DSP-based spectral recovery highly depends on the prior information of transmission functions (TFs) of the filters. The TFs vary with respect to an incident angle of light onto the filter-array. Conventionally, it is assumed that the incident angle of light on the filters is fixed and the TFs are known to the DSP. However, the incident angle is inconstant according to various environments and applications, and thus TFs also vary, which leads to performance degradation of spectral recovery. In this paper, we propose a method of incident angle estimation (IAE) for high resolution spectral recovery in the filter-array-based spectrometers. By exploiting sparse signal reconstruction of the L1- norm minimization, IAE estimates an incident angle among all possible incident angles which minimizes the error of the reconstructed signal. Based on IAE, DSP effectively provides a high resolution spectral recovery in the filter-array-based spectrometers.

  16. Small Pitch Transition-Edge Sensors with Broadband High Spectral Resolution for Solar Physics

    Science.gov (United States)

    Smith, S. J.; Adams, J. S.; Eckart, M. E.; Smith, Adams; Bailey, C. N.; Bandler, S. R.; Chevenak, J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; hide

    2012-01-01

    We are developing small pitch transition-edge sensor (TES) X-ray detectors optimized for solar astronomy. These devices are fabricated on thick Si substrates with embedded Cu heat-sink layer. We use 35 x 35 square micrometers Mo/Au TESs with 4.5 micrometer thick Au absorbers. We have tested devices with different geometric absorber stem contact areas with the TES and surrounding substrate area. This allows us to investigate the loss of athermal phonons to the substrate. Results show a correlation between thc stem contact area and a broadening in the spectral line shape indicative of athermal phonon loss. When the contact area is minimized we have obtained exceptional broadband spectral resolution of 1.28 plus or minus 0.03 eV at an energy of 1.5 keV, 1.58 plus or minus 0.07 eV at 5.9 keV and 1.96 plus or minus 0.08 eV at 8 keV. The linearity in the measured gain scale is understood in the context of the longitudinal proximity effect from the electrical bias leads resulting in transition characteristics that are strongly dependent upon TES size.

  17. Simulating return signals of a spaceborne high-spectral resolution lidar channel at 532 nm

    Science.gov (United States)

    Xiao, Yu; Binglong, Chen; Min, Min; Xingying, Zhang; Lilin, Yao; Yiming, Zhao; Lidong, Wang; Fu, Wang; Xiaobo, Deng

    2018-06-01

    High spectral resolution lidar (HSRL) system employs a narrow spectral filter to separate the particulate (cloud/aerosol) and molecular scattering components in lidar return signals, which improves the quality of the retrieved cloud/aerosol optical properties. To better develop a future spaceborne HSRL system, a novel simulation technique was developed to simulate spaceborne HSRL return signals at 532 nm using the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) cloud/aerosol extinction coefficients product and numerical weather prediction data. For validating simulated data, a mathematical particulate extinction coefficient retrieval method for spaceborne HSRL return signals is described here. We compare particulate extinction coefficient profiles from the CALIPSO operational product with simulated spaceborne HSRL data. Further uncertainty analysis shows that relative uncertainties are acceptable for retrieving the optical properties of cloud and aerosol. The final results demonstrate that they agree well with each other. It indicates that the return signals of the spaceborne HSRL molecular channel at 532 nm will be suitable for developing operational algorithms supporting a future spaceborne HSRL system.

  18. Feasibility of microwave interferometry and fourier-transform spectrometry for high-spectral-resolution sensing

    Energy Technology Data Exchange (ETDEWEB)

    Gerstl, S.; Cooke, B.; Jacobson, A.; Love, S.; Zardecki, A.

    1996-09-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The primary objective of this project was to perform the necessary research and development to determine the feasibility of new ideas that, if successful, could lead to the development of future new programs in high-spectral resolution remote sensing. In active remote sensing systems, the solar illumination of a scene is replaced by a man-made source, preferably a laser beam. However, when laser beams are propagated through a scattering medium, like air, random optical path fluctuations comparable to the optical wavelength are generated giving rise to the speckle effect, which is the most severe perturbation in active remote sensing systems. The limitations introduced by the speckle effect degrade or negate the data interpretation. We sought to introduce better physical models of beam scattering that allow a more realistic simulation environment to be developed that, when applied to experimental data sets, improve their interpretability and increase the information content. Improved beam propagation models require improved knowledge of the spatio-temporal distribution of the scattering and absorbing medium. In the free atmosphere the largest contributor is water vapor in the lower troposphere. We tested the feasibility of using microwave interferometry to measure water-vapor irregularities in the boundary layer. Knowledge of these distributions enable much improved atmospheric correction algorithms for satellite imagery of the earth`s surface to be developed. For hyperspectral active remote sensing systems it is necessary to perform very high-resolution spectral measurements of the reflected laser light. Such measurements are possible with optical interferometers.

  19. Combined Atmospheric and Ocean Profiling from an Airborne High Spectral Resolution Lidar

    Directory of Open Access Journals (Sweden)

    Hair Johnathan

    2016-01-01

    Full Text Available First of its kind combined atmospheric and ocean profile data were collected by the recently upgraded NASA Langley Research Center’s (LaRC High Spectral Resolution Lidar (HSRL-1 during the 17 July – 7 August 2014 Ship-Aircraft Bio-Optical Research Experiment (SABOR. This mission sampled over a region that covered the Gulf of Maine, open-ocean near Bermuda, and coastal waters from Virginia to Rhode Island. The HSRL-1 and the Research Scanning Polarimeter from NASA Goddard Institute for Space Studies collected data onboard the NASA LaRC King Air aircraft and flight operations were closely coordinated with the Research Vessel Endeavor that made in situ ocean optical measurements. The lidar measurements provided profiles of atmospheric backscatter and particulate depolarization at 532nm, 1064nm, and extinction (532nm from approximately 9km altitude. In addition, for the first time HSRL seawater backscatter, depolarization, and diffuse attenuation data at 532nm were collected and compared to both the ship measurements and the Moderate Resolution Imaging Spectrometer (NASA MODIS-Aqua satellite ocean retrievals.

  20. High Frequency High Spectral Resolution Focal Plane Arrays for AtLAST

    Science.gov (United States)

    Baryshev, Andrey

    2018-01-01

    Large collecting area single dish telescope such as ATLAST will be especially effective for medium (R 1000) and high (R 50000) spectral resolution observations. Large focal plane array is a natural solution to increase mapping speed. For medium resolution direct detectors with filter banks (KIDs) and or heterodyne technology can be employed. We will analyze performance limits of comparable KID and SIS focal plane array taking into account quantum limit and high background condition of terrestrial observing site. For large heterodyne focal plane arrays, a high current density AlN junctions open possibility of large instantaneous bandwidth >40%. This and possible multi frequency band FPSs presents a practical challenge for spatial sampling and scanning strategies. We will discuss phase array feeds as a possible solution, including a modular back-end system, which can be shared between KID and SIS based FPA. Finally we will discuss achievable sensitivities and pixel co unts for a high frequency (>500 GHz) FPAs and address main technical challenges: LO distribution, wire counts, bias line multiplexing, and monolithic vs. discrete mixer component integration.

  1. High Spatial Resolution Visual Band Imagery Outperforms Medium Resolution Spectral Imagery for Ecosystem Assessment in the Semi-Arid Brazilian Sertão

    Directory of Open Access Journals (Sweden)

    Ran Goldblatt

    2017-12-01

    Full Text Available Semi-arid ecosystems play a key role in global agricultural production, seasonal carbon cycle dynamics, and longer-run climate change. Because semi-arid landscapes are heterogeneous and often sparsely vegetated, repeated and large-scale ecosystem assessments of these regions have to date been impossible. Here, we assess the potential of high-spatial resolution visible band imagery for semi-arid ecosystem mapping. We use WorldView satellite imagery at 0.3–0.5 m resolution to develop a reference data set of nearly 10,000 labeled examples of three classes—trees, shrubs/grasses, and bare land—across 1000 km 2 of the semi-arid Sertão region of northeast Brazil. Using Google Earth Engine, we show that classification with low-spectral but high-spatial resolution input (WorldView outperforms classification with the full spectral information available from Landsat 30 m resolution imagery as input. Classification with high spatial resolution input improves detection of sparse vegetation and distinction between trees and seasonal shrubs and grasses, two features which are lost at coarser spatial (but higher spectral resolution input. Our total tree cover estimates for the study area disagree with recent estimates using other methods that may underestimate treecover because they confuse trees with seasonal vegetation (shrubs and grasses. This distinction is important for monitoring seasonal and long-run carbon cycle and ecosystem health. Our results suggest that newer remote sensing products that promise high frequency global coverage at high spatial but lower spectral resolution may offer new possibilities for direct monitoring of the world’s semi-arid ecosystems, and we provide methods that could be scaled to do so.

  2. High spatial and spectral resolution measurements of Jupiter's auroral regions using Gemini-North-TEXES

    Science.gov (United States)

    Sinclair, J. A.; Orton, G. S.; Greathouse, T. K.; Lacy, J.; Giles, R.; Fletcher, L. N.; Vogt, M.; Irwin, P. G.

    2017-12-01

    Jupiter exhibits auroral emission at a multitude of wavelengths. Auroral emission at X-ray, ultraviolet and near-infrared wavelengths demonstrate the precipitation of ion and electrons in Jupiter's upper atmosphere, at altitudes exceeding 250 km above the 1-bar level. Enhanced mid-infrared emission of CH4, C2H2, C2H4 and further hydrocarbons is also observed coincident with Jupiter's auroral regions. Retrieval analyses of infrared spectra from IRTF-TEXES (Texas Echelon Cross Echelle Spectrograph on NASA's Infrared Telescope Facility) indicate strong heating at the 1-mbar level and evidence of ion-neutral chemistry, which enriches the abundances of unsaturated hydrocarbons (Sinclair et al., 2017b, doi:10.1002/2017GL073529, Sinclair et al., 2017c (under review)). The extent to which these phenomena in the stratosphere are correlated and coupled physically with the shorter-wavelength auroral emission originating from higher altitudes has been a challenge due to the limited spatial resolution available on the IRTF. Smaller-scale features observed in the near-infrared and ultraviolet emission, such as the main `oval', transient `swirls' and dusk-active regions within the main oval (e.g. Stallard et al., 2014, doi:10.1016/j/Icarus.2015.12.044, Nichols et al., 2017, doi: 10.1002/2017GL073029) are potentially being blurred in the mid-infrared by the diffraction-limited resolution (0.7") of IRTF's 3-metre primary aperture. However, on March 17-19th 2017, we obtained spectral measurements of H2 S(1), CH4, C2H2, C2H4 and C2H6 emission of Jupiter's high latitudes using TEXES on Gemini-North, which has a 8-metre primary aperture. This rare opportunity combines the superior spectral resolving power of TEXES and the high spatial resolution provided by Gemini-North's 8-metre aperture. We will perform a retrieval analyses to determine the 3D distributions of temperature, C2H2, C2H4 and C2H6. The morphology will be compared with near-contemporaneous measurements of H3+ emission from

  3. A high-resolution atlas of composite Sloan Digital Sky Survey galaxy spectra

    Science.gov (United States)

    Dobos, László; Csabai, István.; Yip, Ching-Wa; Budavári, Tamás.; Wild, Vivienne; Szalay, Alexander S.

    2012-02-01

    In this work we present an atlas of composite spectra of galaxies based on the data of the Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Galaxies are classified by colour, nuclear activity and star formation activity to calculate average spectra of high signal-to-noise ratio (S/N) and resolution (? at Δλ= 1 Å), using an algorithm that is robust against outliers. Besides composite spectra, we also compute the first five principal components of the distributions in each galaxy class to characterize the nature of variations of individual spectra around the averages. The continua of the composite spectra are fitted with BC03 stellar population synthesis models to extend the wavelength coverage beyond the coverage of the SDSS spectrographs. Common derived parameters of the composites are also calculated: integrated colours in the most popular filter systems, line-strength measurements and continuum absorption indices (including Lick indices). These derived parameters are compared with the distributions of parameters of individual galaxies, and it is shown on many examples that the composites of the atlas cover much of the parameter space spanned by SDSS galaxies. By co-adding thousands of spectra, a total integration time of several months can be reached, which results in extremely low noise composites. The variations in redshift not only allow for extending the spectral coverage bluewards to the original wavelength limit of the SDSS spectrographs, but also make higher spectral resolution achievable. The composite spectrum atlas is available online at .

  4. Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains central facility

    Directory of Open Access Journals (Sweden)

    J. Delamere

    2011-09-01

    Full Text Available We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM facility at the Southern Great Plains (SGP site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs, four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated can be identified. A normalized difference vegetation index (NDVI is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.

  5. Interferometric filters for spectral discrimination in high-spectral-resolution lidar: performance comparisons between Fabry-Perot interferometer and field-widened Michelson interferometer.

    Science.gov (United States)

    Cheng, Zhongtao; Liu, Dong; Yang, Yongying; Yang, Liming; Huang, Hanlu

    2013-11-10

    Thanks to wavelength flexibility, interferometric filters such as Fabry-Perot interferometers (FPIs) and field-widened Michelson interferometers (FWMIs) have shown great convenience for spectrally separating the molecule and aerosol scattering components in the high-spectral-resolution lidar (HSRL) return signal. In this paper, performance comparisons between the FPI and FWMI as a spectroscopic discrimination filter in HSRL are performed. We first present a theoretical method for spectral transmission analysis and quantitative evaluation on the spectral discrimination. Then the process in determining the parameters of the FPI and FWMI for the performance comparisons is described. The influences from the incident field of view (FOV), the cumulative wavefront error induced by practical imperfections, and the frequency locking error on the spectral discrimination performance of the two filters are discussed in detail. Quantitative analyses demonstrate that FPI can produce higher transmittance while the remarkable spectral discrimination is one of the most appealing advantages of FWMI. As a result of the field-widened design, the FWMI still performs well even under the illumination with large FOV while the FPI is only qualified for a small incident angle. The cumulative wavefront error attaches a great effect on the spectral discrimination performance of the interferometric filters. We suggest if a cumulative wavefront error is less than 0.05 waves RMS, it is beneficial to employ the FWMI; otherwise, FPI may be more proper. Although the FWMI shows much more sensitivity to the frequency locking error, it can outperform the FPI given a locking error less than 0.1 GHz is achieved. In summary, the FWMI is very competent in HSRL applications if these practical engineering and control problems can be solved, theoretically. Some other estimations neglected in this paper can also be carried out through the analytical method illustrated herein.

  6. Exploiting High Resolution Multi-Seasonal Textural Measures and Spectral Information for Reedbed Mapping

    Directory of Open Access Journals (Sweden)

    Alex Okiemute Onojeghuo

    2016-02-01

    Full Text Available Reedbeds across the UK are amongst the most important habitats for rare and endangered birds, wildlife and organisms. However, over the past century, this valued wetland habitat has experienced a drastic reduction in quality and spatial coverage due to pressures from human related activities. To this end, conservation organisations across the UK have been charged with the task of conserving and expanding this threatened habitat. With this backdrop, the study aimed to develop a methodology for accurate reedbed mapping through the combined use of multi-seasonal texture measures and spectral information contained in high resolution QuickBird satellite imagery. The key objectives were to determine the most effective single-date (autumn or summer and multi-seasonal QuickBird imagery suitable for reedbed mapping over the study area; to evaluate the effectiveness of combining multi-seasonal texture measures and spectral information for reedbed mapping using a variety of combinations; and to evaluate the most suitable classification technique for reedbed mapping from three selected classification techniques, namely maximum likelihood classifier, spectral angular mapper and artificial neural network. Using two selected grey-level co-occurrence textural measures (entropy and angular second moment, a series of experiments were conducted using varied combinations of single-date and multi-seasonal QuickBird imagery. Overall, the results indicate the multi-seasonal pansharpened multispectral bands (eight layers combined with all eight grey level co-occurrence matrix texture measures (entropy and angular second moment computed using windows 3 × 3 and 7 × 7 produced the optimal reedbed (76.5% and overall classification (78.1% accuracies using the maximum likelihood classifier technique. Using the optimal 16 layer multi-seasonal pansharpened multispectral and texture combined image dataset, a total reedbed area of 9.8 hectares was successfully mapped over the

  7. High spectral resolution measurements of a solar flare hard X-ray burst

    International Nuclear Information System (INIS)

    Lin, R.P.; Schwartz, R.A.; NASA, Goddard Space Flight Center, Greenbelt, MD)

    1987-01-01

    Observations are reported of an intense solar flare hard X-ray burst on June 27, 1980, made with a balloon-borne array of liquid nitrogen-cooled Ge detector which provided unprecedented spectral resolution (no more than 1 keV FWHM). The hard X-ray spectra throughout the impulsive phase burst fitted well to a double power-law form, and emission from an isothermal 0.1-1 billion K plasma can be specifically excluded. The temporal variations of the spectrum indicate that the hard X-ray burst is made up of two superposed components: individual spikes lasting about 3-15 sec, which have a hard spectrum and a break energy of 30-65 keV; and a slowly varying component characterized by a soft spectrum with a constant low-energy slope and a break energy which increases from 25 kev to at least 100 keV through the event. The double power-law shape indicates that DC electric field acceleration, similar to that occurring in the earth's auroral zone, may be the source of the energetic electrons which produce the hard X-ray emission. 39 references

  8. Coupled-cluster representation of Green function employing modified spectral resolutions of similarity transformed Hamiltonians

    Energy Technology Data Exchange (ETDEWEB)

    Kowalski, K., E-mail: karol.kowalski@pnnl.gov; Bhaskaran-Nair, K.; Shelton, W. A. [William R. Wiley Environmental Molecular Sciences Laboratory, Battelle, Pacific Northwest National Laboratory, K8-91, P.O. Box 999, Richland, Washington 99352 (United States)

    2014-09-07

    In this paper we discuss a new formalism for producing an analytic coupled-cluster (CC) Green's function for an N-electron system by shifting the poles of similarity transformed Hamiltonians represented in N − 1 and N + 1 electron Hilbert spaces. Simple criteria are derived for the states in N − 1 and N + 1 electron spaces that are then corrected in the spectral resolution of the corresponding matrix representations of the similarity transformed Hamiltonian. The accurate description of excited state processes within a Green's function formalism would be of significant importance to a number of scientific communities ranging from physics and chemistry to engineering and the biological sciences. This is because the Green's function methodology provides a direct path for not only calculating properties whose underlying origins come from coupled many-body interactions but also provides a straightforward path for calculating electron transport, response, and correlation functions that allows for a direct link with experiment. As a special case of this general formulation, we discuss the application of this technique for Green's function defined by the CC with singles and doubles representation of the ground-state wave function.

  9. Coupled-cluster representation of Green function employing modified spectral resolutions of similarity transformed Hamiltonians

    Energy Technology Data Exchange (ETDEWEB)

    Kowalski, K. [William R. Wiley Environmental Molecular Sciences Laboratory, Battelle, Pacific Northwest National Laboratory, K8-91, P.O. Box 999, Richland, Washington 99352, USA; Bhaskaran-Nair, K. [William R. Wiley Environmental Molecular Sciences Laboratory, Battelle, Pacific Northwest National Laboratory, K8-91, P.O. Box 999, Richland, Washington 99352, USA; Shelton, W. A. [William R. Wiley Environmental Molecular Sciences Laboratory, Battelle, Pacific Northwest National Laboratory, K8-91, P.O. Box 999, Richland, Washington 99352, USA

    2014-09-07

    In this paper we discuss a new formalism for producing an analytic coupled-cluster (CC) Green's function for an N-electron system by shifting the poles of similarity transformed Hamiltonians represented in N - 1 and N + 1 electron Hilbert spaces. Simple criteria are derived for the states in N - 1 and N + 1 electron spaces that are then corrected in the spectral resolution of the corresponding matrix representations of the similarity transformed Hamiltonian. The accurate description of excited state processes within a Green's function formalism would be of significant importance to a number of scientific communities ranging from physics and chemistry to engineering and the biological sciences. This is because the Green's function methodology provides a direct path for not only calculating properties whose underlying origins come from coupled many-body interactions but also provides a straightforward path for calculating electron transport, response, and correlation functions that allows for a direct link with experiment. Finally, as a special case of this general formulation, we discuss the application of this technique for Green's function defined by the CC with singles and doubles representation of the ground-state wave function.

  10. Coupled-cluster representation of Green function employing modified spectral resolutions of similarity transformed Hamiltonians

    International Nuclear Information System (INIS)

    Kowalski, K.; Bhaskaran-Nair, K.; Shelton, W. A.

    2014-01-01

    In this paper we discuss a new formalism for producing an analytic coupled-cluster (CC) Green's function for an N-electron system by shifting the poles of similarity transformed Hamiltonians represented in N − 1 and N + 1 electron Hilbert spaces. Simple criteria are derived for the states in N − 1 and N + 1 electron spaces that are then corrected in the spectral resolution of the corresponding matrix representations of the similarity transformed Hamiltonian. The accurate description of excited state processes within a Green's function formalism would be of significant importance to a number of scientific communities ranging from physics and chemistry to engineering and the biological sciences. This is because the Green's function methodology provides a direct path for not only calculating properties whose underlying origins come from coupled many-body interactions but also provides a straightforward path for calculating electron transport, response, and correlation functions that allows for a direct link with experiment. As a special case of this general formulation, we discuss the application of this technique for Green's function defined by the CC with singles and doubles representation of the ground-state wave function

  11. Improving quantum efficiency and spectral resolution of a CCD through direct manipulation of the depletion region

    Science.gov (United States)

    Brown, Craig; Ambrosi, Richard M.; Abbey, Tony; Godet, Olivier; O'Brien, R.; Turner, M. J. L.; Holland, Andrew; Pool, Peter J.; Burt, David; Vernon, David

    2008-07-01

    Future generations of X-ray astronomy instruments will require position sensitive detectors in the form of charge-coupled devices (CCDs) for X-ray spectroscopy and imaging with the ability to probe the X-ray universe with greater efficiency. This will require the development of CCDs with structures that will improve their quantum efficiency over the current state of the art. The quantum efficiency improvements would have to span a broad energy range (0.2 keV to >15 keV). These devices will also have to be designed to withstand the harsh radiation environments associated with orbits that extend beyond the Earth's magnetosphere. This study outlines the most recent work carried out at the University of Leicester focused on improving the quantum efficiency of an X-ray sensitive CCD through direct manipulation of the device depletion region. It is also shown that increased spectral resolution is achieved using this method due to a decrease in the number of multi-pixel events. A Monte Carlo and analytical models of the CCD have been developed and used to determine the depletion depths achieved through variation of the device substrate voltage, Vss. The models are also used to investigate multi-pixel event distributions and quantum efficiency as a function of depletion depth.

  12. Airborne High Spectral Resolution Lidar Aerosol Measurements during MILAGRO and TEXAQS/GOMACCS

    Science.gov (United States)

    Ferrare, Richard; Hostetler, Chris; Hair, John; Cook Anthony; Harper, David; Burton, Sharon; Clayton, Marian; Clarke, Antony; Russell, Phil; Redemann, Jens

    2007-01-01

    Two1 field experiments conducted during 2006 provided opportunities to investigate the variability of aerosol properties near cities and the impacts of these aerosols on air quality and radiative transfer. The Megacity Initiative: Local and Global Research Observations (MILAGRO) /Megacity Aerosol Experiment in Mexico City (MAX-MEX)/Intercontinental Chemical Transport Experiment-B (INTEX-B) joint experiment conducted during March 2006 investigated the evolution and transport of pollution from Mexico City. The Texas Air Quality Study (TEXAQS)/Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) (http://www.al.noaa.gov/2006/) conducted during August and September 2006 investigated climate and air quality in the Houston/Gulf of Mexico region. During both missions, the new NASA Langley airborne High Spectral Resolution Lidar (HSRL) was deployed on the NASA Langley B200 King Air aircraft and measured profiles of aerosol extinction, backscattering, and depolarization to: 1) characterize the spatial and vertical distributions of aerosols, 2) quantify aerosol extinction and optical thickness contributed by various aerosol types, 3) investigate aerosol variability near clouds, 4) evaluate model simulations of aerosol transport, and 5) assess aerosol optical properties derived from a combination of surface, airborne, and satellite measurements.

  13. Demonstration of a diode-laser-based high spectral resolution lidar (HSRL) for quantitative profiling of clouds and aerosols.

    Science.gov (United States)

    Hayman, Matthew; Spuler, Scott

    2017-11-27

    We present a demonstration of a diode-laser-based high spectral resolution lidar. It is capable of performing calibrated retrievals of aerosol and cloud optical properties at a 150 m range resolution with less than 1 minute integration time over an approximate range of 12 km during day and night. This instrument operates at 780 nm, a wavelength that is well established for reliable semiconductor lasers and detectors, and was chosen because it corresponds to the D2 rubidium absorption line. A heated vapor reference cell of isotopic rubidium 87 is used as an effective and reliable aerosol signal blocking filter in the instrument. In principle, the diode-laser-based high spectral resolution lidar can be made cost competitive with elastic backscatter lidar systems, yet delivers a significant improvement in data quality through direct retrieval of quantitative optical properties of clouds and aerosols.

  14. High-spatial resolution and high-spectral resolution detector for use in the measurement of solar flare hard x rays

    International Nuclear Information System (INIS)

    Desai, U.D.; Orwig, L.E.

    1988-01-01

    In the areas of high spatial resolution, the evaluation of a hard X-ray detector with 65 micron spatial resolution for operation in the energy range from 30 to 400 keV is proposed. The basic detector is a thick large-area scintillator faceplate, composed of a matrix of high-density scintillating glass fibers, attached to a proximity type image intensifier tube with a resistive-anode digital readout system. Such a detector, combined with a coded-aperture mask, would be ideal for use as a modest-sized hard X-ray imaging instrument up to X-ray energies as high as several hundred keV. As an integral part of this study it was also proposed that several techniques be critically evaluated for X-ray image coding which could be used with this detector. In the area of high spectral resolution, it is proposed to evaluate two different types of detectors for use as X-ray spectrometers for solar flares: planar silicon detectors and high-purity germanium detectors (HPGe). Instruments utilizing these high-spatial-resolution detectors for hard X-ray imaging measurements from 30 to 400 keV and high-spectral-resolution detectors for measurements over a similar energy range would be ideally suited for making crucial solar flare observations during the upcoming maximum in the solar cycle

  15. The Herschel/HIFI unbiased spectral survey of the solar-mass protostar IRAS16293

    Science.gov (United States)

    Bottinelli, S.; Caux, E.; Cecarelli, C.; Kahane, C.

    2012-03-01

    Unbiased spectral surveys are powerful tools to study the chemistry and the physics of star forming regions, because they can provide a complete census of the molecular content and the observed lines probe the physical structure of the source. While unbiased surveys at the millimeter and sub-millimeter wavelengths observable from ground-based telescopes have previously been performed towards several high-mass protostars, very little data exist on low-mass protostars, with only one such ground-based survey carried out towards this kind of object. However, since low-mass protostars are believed to resemble our own Sun's progenitor, the information provided by spectral surveys is crucial in order to uncover the birth mechanisms of low-mass stars and hence of our Sun. To help fill up this gap in our understanding, we carried out an almost complete spectral survey towards the solar-type protostar IRAS16293-2422 with the HIFI instrument onboard Herschel. The observations covered a range of about 700 GHz, in which a few hundreds lines were detected with more than 3σ confidence interval certainty and identified. All the detected lines which were free from obvious blending effects were fitted with Gaussians to estimate their basic kinematic properties. Contrarily to what is observed in the millimeter range, no lines from complex organic molecules have been observed. In this work, we characterize the different components of IRAS16293-2422 (a known binary at least) by analyzing the numerous emission and absorption lines identified.

  16. High Spectral Resolution LIDAR as a Tool for Air Quality Research

    Science.gov (United States)

    Eloranta, E. W.; Spuler, S.; Hayman, M. M.

    2017-12-01

    Many aspects of air quality research require information on the vertical distribution of pollution. Traditional measurements, obtained from surface based samplers, or passive satellite remote sensing, do not provide vertical profiles. Lidar can provide profiles of aerosol properties. However traditional backscatter lidar suffers from uncertain calibrations with poorly constrained algorithms. These problems are avoided using High Spectral Resolution Lidar (HSRL) which provides absolutely calibrated vertical profiles of aerosol properties. The University of Wisconsin HSRL systems measure 532 nm wavelength aerosol backscatter cross-sections, extinction cross-sections, depolarization, and attenuated 1064 nm backscatter. These instruments are designed for long-term deployment at remote sites with minimal local support. Processed data is provided for public viewing and download in real-time on our web site "http://hsrl.ssec.wisc.edu". Air pollution applications of HSRL data will be illustrated with examples acquired during air quality field programs including; KORUS-AQ, DISCOVER-AQ, LAMOS and FRAPPE. Observations include 1) long range transport of dust, air pollution and smoke. 2) Fumigation episodes where elevated pollution is mixed down to the surface. 3) visibility restrictions by aerosols and 4) diurnal variations in atmospheric optical depth. While HSRL is powerful air quality research tool, its application in routine measurement networks is hindered by the high cost of current systems. Recent technical advances promise a next generation HSRL using telcom components to greatly reduce system cost. This paper will present data generated by a prototype low cost system constructed at NCAR. In addition to lower cost, operation at a non-visible near 780 nm infrared wavelength removes all FAA restrictions on the operation.

  17. High-resolution seismic reflection surveying with a land streamer

    Science.gov (United States)

    Cengiz Tapırdamaz, Mustafa; Cankurtaranlar, Ali; Ergintav, Semih; Kurt, Levent

    2013-04-01

    In this study, newly designed seismic reflection data acquisition array (land streamer) is utilized to image the shallow subsurface. Our acquisition system consist of 24 geophones screwed on iron plates with 2 m spacing, moving on the surface of the earth which are connected with fire hose. Completely original, 4.5 Kg weight iron plates provides satisfactory coupling. This land-streamer system enables rapid and cost effective acquisition of seismic reflection data due to its operational facilities. First test studies were performed using various seismic sources such as a mini-vibro truck, buffalo-gun and hammer. The final fieldwork was performed on a landslide area which was studied before. Data acquisition was carried out on the line that was previously measured by the seismic survey using 5 m geophone and shot spacing. This line was chosen in order to re-image known reflection patterns obtained from the previous field study. Taking penetration depth into consideration, a six-cartridge buffalo-gun was selected as a seismic source to achieve high vertical resolution. Each shot-point drilled 50 cm for gunshots to obtain high resolution source signature. In order to avoid surface waves, the offset distance between the source and the first channel was chosen to be 50 m and the shot spacing was 2 m. These acquisition parameters provided 12 folds at each CDP points. Spatial sampling interval was 1 m at the surface. The processing steps included standard stages such as gain recovery, editing, frequency filtering, CDP sorting, NMO correction, static correction and stacking. Furthermore, surface consistent residual static corrections were applied recursively to improve image quality. 2D F-K filter application was performed to suppress air and surface waves at relatively deep part of the seismic section. Results show that, this newly designed, high-resolution land seismic data acquisition equipment (land-streamer) can be successfully used to image subsurface. Likewise

  18. Assessment of Spectral and Temporal Resolution in Cochlear Implant Users Using Psychoacoustic Discrimination and Speech Cue Categorization.

    Science.gov (United States)

    Winn, Matthew B; Won, Jong Ho; Moon, Il Joon

    This study was conducted to measure auditory perception by cochlear implant users in the spectral and temporal domains, using tests of either categorization (using speech-based cues) or discrimination (using conventional psychoacoustic tests). The authors hypothesized that traditional nonlinguistic tests assessing spectral and temporal auditory resolution would correspond to speech-based measures assessing specific aspects of phonetic categorization assumed to depend on spectral and temporal auditory resolution. The authors further hypothesized that speech-based categorization performance would ultimately be a superior predictor of speech recognition performance, because of the fundamental nature of speech recognition as categorization. Nineteen cochlear implant listeners and 10 listeners with normal hearing participated in a suite of tasks that included spectral ripple discrimination, temporal modulation detection, and syllable categorization, which was split into a spectral cue-based task (targeting the /ba/-/da/ contrast) and a timing cue-based task (targeting the /b/-/p/ and /d/-/t/ contrasts). Speech sounds were manipulated to contain specific spectral or temporal modulations (formant transitions or voice onset time, respectively) that could be categorized. Categorization responses were quantified using logistic regression to assess perceptual sensitivity to acoustic phonetic cues. Word recognition testing was also conducted for cochlear implant listeners. Cochlear implant users were generally less successful at utilizing both spectral and temporal cues for categorization compared with listeners with normal hearing. For the cochlear implant listener group, spectral ripple discrimination was significantly correlated with the categorization of formant transitions; both were correlated with better word recognition. Temporal modulation detection using 100- and 10-Hz-modulated noise was not correlated either with the cochlear implant subjects' categorization of

  19. The protostar OMC-2 FIR 4: Results from the CHESS Herschel/HIFI spectral survey

    Science.gov (United States)

    Kama, Mihkel; Lopez-Sepulcre, Ana; Ceccarelli, Cecilia; Dominik, Carsten; Caux, Emmanuel; Fuente, Asuncion

    2013-07-01

    The intermediate-mass protostar OMC-2 FIR 4 in Orion is the focus of several ongoing studies, including a CHESS key programme Herschel/HIFI spectral survey. In this poster, we review recent CHESS results on this source, including the properties of the central hot core, the presence of a compact outflow, the spatial variation of the chemical composition, and the discovery of a tenuous foreground cloud. The HIFI spectrum of FIR 4 contains 719 lines from 40 species and isotopologs. Cooling by lines detectable with our sensitivity contributes 2% of the total in the 480 to 1900 GHz range. The total line flux is dominated by CO, followed by H2O and CH3OH. Initial comparisons with spectral surveys of other sources will also be presented.

  20. Analysis of the Herschel/HIFI 1.2 THz Wide Spectral Survey of the Orion Kleinmann-Low Nebula

    Science.gov (United States)

    Crockett, Nathan R.

    This dissertation presents a comprehensive analysis of a broad band spectral line survey of the Orion Kleinmann-Low nebula (Orion KL), one of the most chemically rich regions in the Galaxy, using the HIFI instrument on board the Herschel Space Observatory. This survey spans a frequency range from 480 to 1907 GHz at a resolution of 1.1 MHz. These observations thus encompass the largest spectral coverage ever obtained toward this massive star forming region in the sub-mm with high spectral resolution, and include frequencies >1 THz where the Earth's atmosphere prevents observations from the ground. In all, we detect emission from 36 molecules (76 isotopologues). Combining this dataset with ground based mm spectroscopy obtained with the IRAM 30 m telescope, we model the molecular emission assuming local thermodynamic equilibrium (LTE). Because of the wide frequency coverage, our models are constrained over an unprecedented range in excitation energy, including states at or close to ground up to energies where emission is no longer detected. A χ2 analysis indicates that most of our models reproduce the observed emission well. In particular complex organics, some with thousands of transitions, are well fit by LTE models implying that gas densities are high (>10^6 cm^-3) and excitation temperatures and column densities are well constrained. Molecular abundances are computed using H2 column densities also derived from the HIFI survey. The rotation temperature distribution of molecules detected toward the hot core is much wider relative to the compact ridge, plateau, and extended ridge. We find that complex N-bearing species, cyanides in particular, systematically probe hotter gas than complex O-bearing species. This indicates complex N-bearing molecules may be more difficult to remove from grain surfaces or that hot gas phase formation routes are important for these species. We also present a detailed non-LTE analysis of H2S emission toward the hot core which suggests

  1. High-resolution grazing-incidence grating spectrometer for temperature measurements of low-Z ions emitting in the 100-300 Å spectral banda)

    Science.gov (United States)

    Widmann, K.; Beiersdorfer, P.; Magee, E. W.; Boyle, D. P.; Kaita, R.; Majeski, R.

    2014-11-01

    We have constructed a high-resolution grazing-incidence spectrometer designed for measuring the ion temperature of low-Z elements, such as Li+ or Li2 +, which radiate near 199 Å and 135 Å, respectively. Based on measurements at the Livermore Electron Beam Ion Trap we have shown that the instrumental resolution is better than 48 mÅ at the 200 Å setting and better than 40 mÅ for the 135-Å range. Such a high spectral resolution corresponds to an instrumental limit for line-width based temperature measurements of about 45 eV for the 199 Å Li+ and 65 eV for the 135 Å Li2 + lines. Recently obtained survey spectra from the Lithium Tokamak Experiment at the Princeton Plasma Physics Laboratory show the presence of these lithium emission lines and the expected core ion temperature of approximately 70 eV is sufficiently high to demonstrate the feasibility of utilizing our high-resolution spectrometer as an ion-temperature diagnostic.

  2. High-resolution grazing-incidence grating spectrometer for temperature measurements of low-Z ions emitting in the 100–300 Å spectral band

    Energy Technology Data Exchange (ETDEWEB)

    Widmann, K., E-mail: widmann1@llnl.gov; Beiersdorfer, P.; Magee, E. W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Boyle, D. P.; Kaita, R.; Majeski, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-11-15

    We have constructed a high-resolution grazing-incidence spectrometer designed for measuring the ion temperature of low-Z elements, such as Li{sup +} or Li{sup 2+}, which radiate near 199 Å and 135 Å, respectively. Based on measurements at the Livermore Electron Beam Ion Trap we have shown that the instrumental resolution is better than 48 mÅ at the 200 Å setting and better than 40 mÅ for the 135-Å range. Such a high spectral resolution corresponds to an instrumental limit for line-width based temperature measurements of about 45 eV for the 199 Å Li{sup +} and 65 eV for the 135 Å Li{sup 2+} lines. Recently obtained survey spectra from the Lithium Tokamak Experiment at the Princeton Plasma Physics Laboratory show the presence of these lithium emission lines and the expected core ion temperature of approximately 70 eV is sufficiently high to demonstrate the feasibility of utilizing our high-resolution spectrometer as an ion-temperature diagnostic.

  3. A high-resolution two-pulse coherent anti-Stokes Raman scattering spectrum using a spectral amplitude modulation

    International Nuclear Information System (INIS)

    Lu, Chenhui; Zhang, Shian; Wu, Meizhen; Jia, Tianqing; Sun, Zhenrong; Qiu, Jianrong

    2013-01-01

    Femtosecond coherent anti-Stokes Raman scattering (CARS) spectra suffer from low spectral resolution because of the broadband laser spectrum. In this paper, we propose a feasible scheme to achieve a high-resolution two-pulse CARS spectrum by shaping both the pump and probe pulses using rectangular amplitude modulation. We show that a narrowband hole in the CARS spectrum can be created by the amplitude-shaped laser pulse, the position of which is correlated with the Raman resonant frequency of the molecule. Thus, by observing holes in the CARS spectrum, we are able to obtain a high-resolution CARS spectrum and the energy-level diagram of the molecule. (paper)

  4. Technical Note: Continuity of MIPAS-ENVISAT operational ozone data quality from full- to reduced-spectral-resolution operation mode

    Directory of Open Access Journals (Sweden)

    S. Ceccherini

    2008-04-01

    Full Text Available MIPAS (Michelson Interferometer for Passive Atmospheric Sounding is operating on the ENVIronmental SATellite (ENVISAT since March 2002. After two years of nearly continuous limb scanning measurements, at the end of March 2004, the instrument was stopped due to problems with the mirror drive of the interferometer. Operations with reduced maximum path difference, corresponding to both a reduced-spectral-resolution and a shorter measurement time, were resumed on January 2005. In order to exploit the reduction in measurement time, the measurement scenario was changed adopting a finer vertical limb scanning. The change of spectral resolution and of measurement scenario entailed an update of the data processing strategy. The aim of this paper is the assessment of the differences in the quality of the MIPAS ozone data acquired before and after the stop of the operations. Two sets of MIPAS ozone profiles acquired in 2003–2004 (full-resolution measurements and in 2005–2006 (reduced-resolution measurements are compared with collocated ozone profiles obtained by GOMOS (Global Ozone Monitoring by Occultation of Stars, itself also onboard ENVISAT. The continuity of the GOMOS data quality allows to assess a possible discontinuity of the MIPAS performances. The relative bias and precision of MIPAS ozone profiles with respect to the GOMOS ones have been compared for the measurements acquired before and after the stop of the MIPAS operations. The results of the comparison show that, in general, the quality of the MIPAS ozone profiles retrieved from reduced-resolution measurements is comparable or better than that obtained from the full-resolution dataset. The only significant change in MIPAS performances is observed at pressures around 2 unit{hPa}, where the relative bias of the instruments increases by a factor of 2 from the 2003–2004 to 2005–2006 measurements.

  5. Assessing the Impact of Spectral Resolution on Classification of Lowland Native Grassland Communities Based on Field Spectroscopy in Tasmania, Australia

    Directory of Open Access Journals (Sweden)

    Bethany Melville

    2018-02-01

    Full Text Available This paper presents a case study for the analysis of endangered lowland native grassland communities in the Tasmanian Midlands region using field spectroscopy and spectral convolution techniques. The aim of the study was to determine whether there was significant improvement in classification accuracy for lowland native grasslands and other vegetation communities based on hyperspectral resolution datasets over multispectral equivalents. A spectral dataset was collected using an ASD Handheld-2 spectroradiometer at Tunbridge Township Lagoon. The study then employed a k-fold cross-validation approach for repeated classification of a full hyperspectral dataset, a reduced hyperspectral dataset, and two convoluted multispectral datasets. Classification was performed on each of the four datasets a total of 30 times, based on two different class configurations. The classes analysed were Themeda triandra grassland, Danthonia/Poa grassland, Wilsonia rotundifolia/Selliera radicans, saltpan, and a simplified C3 vegetation class. The results of the classifications were then tested for statistically significant differences using ANOVA and Tukey’s post-hoc comparisons. The results of the study indicated that hyperspectral resolution provides small but statistically significant increases in classification accuracy for Themeda and Danthonia grasslands. For other classes, differences in classification accuracy for all datasets were not statistically significant. The results obtained here indicate that there is some potential for enhanced detection of major lowland native grassland community types using hyperspectral resolution datasets, and that future analysis should prioritise good performance in these classes over others. This study presents a method for identification of optimal spectral resolution across multiple datasets, and constitutes an important case study for lowland native grassland mapping in Tasmania.

  6. A survey of the modern auto- and cross-spectral analyses for the purpose of tokamak study

    International Nuclear Information System (INIS)

    Iwama, N.

    1984-09-01

    The modern techniques of digital auto- and cross-spectral analyses are surveyed for the purpose of the CO 2 -laser scattering experiment on the microinstability and the associated anomalous diffusion in TFR tokamak. The outline of the practical procedures of spectral estimation and the underlying mathematical principles are described with emphasis on the comparison between the maximum entropy method and the conventional methods. The statistical properties of the spectral estimators are discussed and examined by experiments

  7. Analysis of the Herschel/Hexos Spectral Survey Toward Orion South: A Massive Protostellar Envelope with Strong External Irradiation

    NARCIS (Netherlands)

    Tahani, K.; Plume, R.; Bergin, E. A.; Tolls, V.; Phillips, T. G.; Caux, E.; Cabrit, S.; Goicoechea, J. R.; Goldsmith, P. F.; Johnstone, D.; Lis, D. C.; Pagani, L.; Menten, K. M.; Müller, H. S. P.; Ossenkopf-Okada, V.; Pearson, J. C.; van der Tak, F. F. S.

    2016-01-01

    We present results from a comprehensive submillimeter spectral survey toward the source Orion South, based on data obtained with the Heterodyne Instrument for the Far-Infrared instrument on board the Herschel Space Observatory, covering the frequency range of 480 to 1900 GHz. We detect 685 spectral

  8. Combined High Spectral Resolution Lidar and Millimeter Wavelength Radar Measurement of Ice Crystal Precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Eloranta, Edwin [Univ. of Wisconsin, Madison, WI (United States)

    2016-10-28

    The goal of this research has been to improve measurements of snowfall using a combination of millimeter-wavelength radar and High Spectral Resolution Lidar (HSRL) Observations. Snowflakes are large compared to the 532nm HSRL wavelength and small compared to the 3.2 and 8.6 mm wavelength radars used in this study. This places the particles in the optical scattering regime of the HSRL, where extinction cross-section is proportional to the projected area of the particles, and in the Rayleigh regime for the radar, where the backscatter cross-section is proportional to the mass-squared of the particles. Forming a ratio of the radar measured cross-section to the HSRL measured cross section eliminates any dependence on the number of scattering particles, yielding a quantity proportional to the average mass-squared of the snowflakes over the average area of the flakes. Using simultaneous radar measurements of particle fall velocities, which are dependent particle mass and cross-sectional area it is possible to derive the average mass of the snow flakes, and with the radar measured fall velocities compute the snowfall rate. Since this retrieval requires the optical extinction cross-section we began by considering errors this quantity. The HSRL is particularly good at measuring the backscatter cross-section. In previous studies of snowfall in the high Arctic were able to estimate the extinction cross-section directly as a fixed ratio to the backscatter cross-section. Measurements acquired in the STORMVEX experiment in Colorado showed that this approach was not valid in mid-latitude snowfalls and that direct measurement of the extinction cross-section is required. Attempts to measure the extinction directly uncovered shortcomings in thermal regulation and mechanical stability of the newly deployed DOE HSRL systems. These problems were largely mitigated by modifications installed in both of the DOE systems. We also investigated other sources of error in the HSRL direct

  9. Acoustic Event Detection in Multichannel Audio Using Gated Recurrent Neural Networks with High‐Resolution Spectral Features

    Directory of Open Access Journals (Sweden)

    Hyoung‐Gook Kim

    2017-12-01

    Full Text Available Recently, deep recurrent neural networks have achieved great success in various machine learning tasks, and have also been applied for sound event detection. The detection of temporally overlapping sound events in realistic environments is much more challenging than in monophonic detection problems. In this paper, we present an approach to improve the accuracy of polyphonic sound event detection in multichannel audio based on gated recurrent neural networks in combination with auditory spectral features. In the proposed method, human hearing perception‐based spatial and spectral‐domain noise‐reduced harmonic features are extracted from multichannel audio and used as high‐resolution spectral inputs to train gated recurrent neural networks. This provides a fast and stable convergence rate compared to long short‐term memory recurrent neural networks. Our evaluation reveals that the proposed method outperforms the conventional approaches.

  10. Herschel/HIFI spectral line survey of the Orion Bar. Temperature and density differentiation near the PDR surface

    Science.gov (United States)

    Nagy, Z.; Choi, Y.; Ossenkopf-Okada, V.; van der Tak, F. F. S.; Bergin, E. A.; Gerin, M.; Joblin, C.; Röllig, M.; Simon, R.; Stutzki, J.

    2017-03-01

    Context. Photon dominated regions (PDRs) are interfaces between the mainly ionized and mainly molecular material around young massive stars. Analysis of the physical and chemical structure of such regions traces the impact of far-ultraviolet radiation of young massive stars on their environment. Aims: We present results on the physical and chemical structure of the prototypical high UV-illumination edge-on Orion Bar PDR from an unbiased spectral line survey with a wide spectral coverage which includes lines of many important gas coolants such as [Cii], [Ci], and CO and other key molecules such as H2CO, H2O, HCN, HCO+, and SO. Methods: A spectral scan from 480-1250 GHz and 1410-1910 GHz at 1.1 MHz resolution was obtained by the HIFI instrument on board the Herschel Space Observatory. We obtained physical parameters for the observed molecules. For molecules with multiple transitions we used rotational diagrams to obtain excitation temperatures and column densities. For species with a single detected transition we used an optically thin LTE approximation. In the case of species with available collisional rates, we also performed a non-LTE analysis to obtain kinetic temperatures, H2 volume densities, and column densities. Results: About 120 lines corresponding to 29 molecules (including isotopologues) have been detected in the Herschel/HIFI line survey, including 11 transitions of CO, 7 transitions of 13CO, 6 transitions of C18O, 10 transitions of H2CO, and 6 transitions of H2O. The rotational temperatures are in the range between 22 and 146 K and the column densities are in the range between 1.8 × 1012 cm-2 and 4.5 × 1017 cm-2. For species with at least three detected transitions and available collisional excitation rates we derived a best fit kinetic temperature and H2 volume density. Most species trace kinetic temperatures in the range between 100 and 150 K and H2 volume densities in the range between 105 and 106 cm-3. The species with temperatures and

  11. High spatial resolution three-dimensional mapping of vegetation spectral dynamics using computer vision and hobbyist unmanned aerial vehicles

    Science.gov (United States)

    Dandois, J. P.; Ellis, E. C.

    2013-12-01

    High spatial resolution three-dimensional (3D) measurements of vegetation by remote sensing are advancing ecological research and environmental management. However, substantial economic and logistical costs limit this application, especially for observing phenological dynamics in ecosystem structure and spectral traits. Here we demonstrate a new aerial remote sensing system enabling routine and inexpensive aerial 3D measurements of canopy structure and spectral attributes, with properties similar to those of LIDAR, but with RGB (red-green-blue) spectral attributes for each point, enabling high frequency observations within a single growing season. This 'Ecosynth' methodology applies photogrammetric ''Structure from Motion'' computer vision algorithms to large sets of highly overlapping low altitude (USA. Ecosynth canopy height maps (CHMs) were strong predictors of field-measured tree heights (R2 0.63 to 0.84) and were highly correlated with a LIDAR CHM (R 0.87) acquired 4 days earlier, though Ecosynth-based estimates of aboveground biomass densities included significant errors (31 - 36% of field-based estimates). Repeated scanning of a 0.25 ha forested area at six different times across a 16 month period revealed ecologically significant dynamics in canopy color at different heights and a structural shift upward in canopy density, as demonstrated by changes in vertical height profiles of point density and relative RGB brightness. Changes in canopy relative greenness were highly correlated (R2 = 0.88) with MODIS NDVI time series for the same area and vertical differences in canopy color revealed the early green up of the dominant canopy species, Liriodendron tulipifera, strong evidence that Ecosynth time series measurements capture vegetation structural and spectral dynamics at the spatial scale of individual trees. Observing canopy phenology in 3D at high temporal resolutions represents a breakthrough in forest ecology. Inexpensive user-deployed technologies for

  12. Metabolite Identification Using Automated Comparison of High-Resolution Multistage Mass Spectral Trees

    NARCIS (Netherlands)

    Rojas-Cherto, M.; Peironcely, J.E.; Kasper, P.T.; Hooft, van der J.J.J.; Vos, de R.C.H.; Vreeken, R.; Hankemeier, T.; Reijmers, T.

    2012-01-01

    Multistage mass spectrometry (MSn) generating so-called spectral trees is a powerful tool in the annotation and structural elucidation of metabolites and is increasingly used in the area of accurate mass LC/MS-based metabolomics to identify unknown, but biologically relevant, compounds. As a

  13. High spectral resolution observations of the H2 2.12 micron line in Herbig-Haro objects

    International Nuclear Information System (INIS)

    Zinnecker, H.; Mundt, R.; Geballe, T.R.; Zealey, W.J.

    1989-01-01

    High-spectral-resolution Fabry-Perot observations of the H 2 2.12-micron line emissions of several Herbig-Haro (HH) objects are discussed. It is shown that H 2 emission by the shock heating of external molecular gas in the wings of the bow shock associated with the working surface of a high-velocity jet may occur for HH objects associated with the jet's end. The shock heating of external molecular gas entrained in the flow by internal shocks occurring in the jet itself and/or in its boundary layer may be the H 2 emission mechanism for HH objects observed along the flow axis. 59 refs

  14. Spectral Resolution for Five-Element, Filtered, X-Ray Detector (XRD) Arrays Using the Methods of Backus and Gilbert

    International Nuclear Information System (INIS)

    FEHL, DAVID LEE; BIGGS, F.; CHANDLER, GORDON A.; STYGAR, WILLIAM A.

    2000-01-01

    The generalized method of Backus and Gilbert (BG) is described and applied to the inverse problem of obtaining spectra from a 5-channel, filtered array of x-ray detectors (XRD's). This diagnostic is routinely fielded on the Z facility at Sandia National Laboratories to study soft x-ray photons ((le)2300 eV), emitted by high density Z-pinch plasmas. The BG method defines spectral resolution limits on the system of response functions that are in good agreement with the unfold method currently in use. The resolution so defined is independent of the source spectrum. For noise-free, simulated data the BG approximating function is also in reasonable agreement with the source spectrum (150 eV black-body) and the unfold. This function may be used as an initial trial function for iterative methods or a regularization model

  15. An Interferometric Spectral Line and Imaging Survey of VY Canis Majoris in the 345 GHz Band

    Science.gov (United States)

    Kamiński, T.; Gottlieb, C. A.; Young, K. H.; Menten, K. M.; Patel, N. A.

    2013-12-01

    A spectral line survey of the oxygen-rich red supergiant VY Canis Majoris was made between 279 and 355 GHz with the Submillimeter Array (SMA). Two hundred twenty-three spectral features from 19 molecules (not counting isotopic species of some of them) were observed, including the rotational spectra of TiO, TiO2, and AlCl for the first time in this source. The parameters and an atlas of all spectral features are presented. Observations of each line with a synthesized beam of ~0.''9, reveal the complex kinematics and morphology of the nebula surrounding VY CMa. Many of the molecules are observed in high-lying rotational levels or in excited vibrational levels. From these, it was established that the main source of the submillimeter-wave continuum (dust) and the high-excitation molecular gas (the star) are separated by about 0.''15. Apparent coincidences between the molecular gas observed with the SMA, and some of the arcs and knots observed at infrared wavelengths and in the optical scattered light by the Hubble Space Telescope are identified. The observations presented here provide important constraints on the molecular chemistry in oxygen-dominated circumstellar environments and a deeper picture of the complex circumstellar environment of VY CMa.

  16. TIMASSS: the IRAS 16293-2422 millimeter and submillimeter spectral survey. I. Observations, calibration, and analysis of the line kinematics

    Science.gov (United States)

    Caux, E.; Kahane, C.; Castets, A.; Coutens, A.; Ceccarelli, C.; Bacmann, A.; Bisschop, S.; Bottinelli, S.; Comito, C.; Helmich, F. P.; Lefloch, B.; Parise, B.; Schilke, P.; Tielens, A. G. G. M.; van Dishoeck, E.; Vastel, C.; Wakelam, V.; Walters, A.

    2011-08-01

    of both objects is consistent with the hypothesis that the source B rotates around the source A. Conclusions: This spectral survey, although obtained with single-dish telescopes at a low spatial resolution, allows us to separate the emission from two different components, thanks to the large number of lines detected. The data of the survey are public and can be retrieved on the TIMASSS web site. Based on observations with the IRAM-30 m telescope (IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain)), and with the JCMT-15 m telescope (operated by the Joint Astronomy Centre on behalf of the Particle Physics and Astronomy Research Council of the United Kingdom, the Netherlands Organisation of Scientific Research, and the National Research Council of Canada).Tables 2-4 are available in electronic form at http://www.aanda.orgSurvey data is available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/532/A23.

  17. A Global Survey of Cloud Thermodynamic Phase using High Spatial Resolution VSWIR Spectroscopy, 2005-2015

    Science.gov (United States)

    Thompson, D. R.; Kahn, B. H.; Green, R. O.; Chien, S.; Middleton, E.; Tran, D. Q.

    2017-12-01

    Clouds' variable ice and liquid content significantly influences their optical properties, evolution, and radiative forcing potential (Tan and Storelvmo, J. Atmos. Sci, 73, 2016). However, most remote measurements of thermodynamic phase have spatial resolutions of 1 km or more and are insensitive to mixed phases. This under-constrains important processes, such as spatial partitioning within mixed phase clouds, that carry outsize radiative forcing impacts. These uncertainties could shift Global Climate Model (GCM) predictions of future warming by over 1 degree Celsius (Tan et al., Science 352:6282, 2016). Imaging spectroscopy of reflected solar energy from the 1.4 - 1.8 μm shortwave infrared (SWIR) spectral range can address this observational gap. These observations can distinguish ice and water absorption, providing a robust and sensitive measurement of cloud top thermodynamic phase including mixed phases. Imaging spectrometers can resolve variations at scales of tens to hundreds of meters (Thompson et al., JGR-Atmospheres 121, 2016). We report the first such global high spatial resolution (30 m) survey, based on data from 2005-2015 acquired by the Hyperion imaging spectrometer onboard NASA's EO-1 spacecraft (Pearlman et al., Proc. SPIE 4135, 2001). Estimated seasonal and latitudinal distributions of cloud thermodynamic phase generally agree with observations made by other satellites such as the Atmospheric Infrared Sounder (AIRS). Variogram analyses reveal variability at different spatial scales. Our results corroborate previously observed zonal distributions, while adding insight into the spatial scales of processes governing cloud top thermodynamic phase. Figure: Thermodynamic phase retrievals. Top: Example of a cloud top thermodynamic phase map from the EO-1/Hyperion. Bottom: Latitudinal distributions of pure and mixed phase clouds, 2005-2015, showing Liquid Thickness Fraction (LTF). LTF=0 corresponds to pure ice absorption, while LTF=1 is pure liquid. The

  18. Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS): Stony Asteroids Abundant in the Background and Family Populations

    Science.gov (United States)

    Lucas, Michael P.; Emery, Joshua P.; Pinilla-Alonso, Noemi; Lindsay, Sean S.; Lorenzi, Vania

    2016-10-01

    The Hungaria region represents a "purgatory" for the closest, preserved samples of the material from which the terrestrial planets accreted. The Hungaria region harbors a collisional family of Xe-type asteroids, which are situated among a background of predominantly S-complex asteroids. Deciphering their surface composition may provide constraints on the nature of the primordial building blocks of the terrestrial planets. We hypothesize that planetesimals in the inner part of the primordial asteroid belt experienced partial- to full-melting and differentiation, the Hungaria region should retain any petrologically-evolved material that formed there.We have undertaken an observational campaign entitled the Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) to record near-infrared (NIR) spectra to characterize taxonomy, surface mineralogy, and potential meteorite analogs. We used NIR instruments at two ground-based facilities (NASA IRTF; TNG). Our data set includes spectra of 82 Hungaria asteroids (61 background; 21 family), 65 were observed during HARTSS. We compare S-complex background asteroids to calibrations developed via laboratory analyses of ordinary chondrites, and to our analyses (EPMA, XRD, VIS+NIR spectra) of 11 primitive achondrite (acapulcoite-lodranite clan) meteorites.We find that stony S-complex asteroids dominate the Hungaria background population (~80%). Background objects exhibit considerable spectral diversity, when quantified by spectral band parameter measurements, translates to a variety of surface compositions. Two main meteorite groups are represented within the Hungaria background: unmelted, nebular L chondrites (and/or L chondrites), and partially-melted primitive achondrites. H-chondrite mineralogies appear to be absent from the Hungaria background. Xe-type Hungaria family members exhibit spectral homogeneity, consistent with the hypothesis that the family was derived from the disruption of a parent body analogous to an enstatite

  19. Temporal measurement and analysis of high-resolution spectral signatures of plants and relationships to biophysical characteristics

    Science.gov (United States)

    Bostater, Charles R., Jr.; Rebbman, Jan; Hall, Carlton; Provancha, Mark; Vieglais, David

    1995-11-01

    Measurements of temporal reflectance signatures as a function of growing season for sand live oak (Quercus geminata), myrtle oak (Q. myrtifolia, and saw palmetto (Serenoa repens) were collected during a two year study period. Canopy level spectral reflectance signatures, as a function of 252 channels between 368 and 1115 nm, were collected using near nadir viewing geometry and a consistent sun illumination angle. Leaf level reflectance measurements were made in the laboratory using a halogen light source and an environmental optics chamber with a barium sulfate reflectance coating. Spectral measurements were related to several biophysical measurements utilizing optimal passive ambient correlation spectroscopy (OPACS) technique. Biophysical parameters included percent moisture, water potential (MPa), total chlorophyll, and total Kjeldahl nitrogen. Quantitative data processing techniques were used to determine optimal bands based on the utilization of a second order derivative or inflection estimator. An optical cleanup procedure was then employed that computes the double inflection ratio (DIR) spectra for all possible three band combinations normalized to the previously computed optimal bands. These results demonstrate a unique approach to the analysis of high spectral resolution reflectance signatures for estimation of several biophysical measures of plants at the leaf and canopy level from optimally selected bands or bandwidths.

  20. Optimization of a Michelson interferometer with a rotating retroreflector in opitcal design, spectral resolution, and optical throughput

    International Nuclear Information System (INIS)

    Haschberger, P.; Tank, V.

    1993-01-01

    A newly designed Michelson interferometer for Fourier spectroscopy utilizes a nutating retroreflector (cube corner mirror) to generate alterations in geometrical and optical paths. The practical optomechanical design of a Fourier-transform spectrometer incorporating a rotating retroreflector for path-length alteration is considered. (The instrument has been given the name MIROR, for Michelson Interferometer with a Rotating Retroreflector.) Two parameters of the instrument are essential: the maximum optical path difference, which yields the spectral resolution of the instrument, and the diameter of the transmitted beam, which determines the throughput and hence the achievable signal-to-noise ratio. The maximum allowable beam diameter is calculated as a function of the geometry and the orientation of the rotating retroreflector and the other optical components. The geometrical configuration and the orientation of all the optical components with respect to one another are also optimized for the maximum transmitted beam diameter when the required path difference is given. A principal investigation of different possible configurations of the optical components is presented. Then a quantitative optimization for an interferometer employing a retroreflector having a 5-in. (12.7-cm) aperture diameter requiring an optical path difference of more than 10 cm (spectral resolution better than 0.1 cm -1 ) is performed. Finally a simplified but enhanced design is described. 10 refs., 15 figs

  1. The "+" for CRIRES: enabling better science at infrared wavelength and high spectral resolution at the ESO VLT

    Science.gov (United States)

    Dorn, Reinhold J.; Follert, Roman; Bristow, Paul; Cumani, Claudio; Eschbaumer, Siegfried; Grunhut, Jason; Haimerl, Andreas; Hatzes, Artie; Heiter, Ulrike; Hinterschuster, Renate; Ives, Derek J.; Jung, Yves; Kerber, Florian; Klein, Barbara; Lavaila, Alexis; Lizon, Jean Louis; Löwinger, Tom; Molina-Conde, Ignacio; Nicholson, Belinda; Marquart, Thomas; Oliva, Ernesto; Origlia, Livia; Pasquini, Luca; Paufique, Jérôme; Piskunov, Nikolai; Reiners, Ansgar; Seemann, Ulf; Stegmeier, Jörg; Stempels, Eric; Tordo, Sebastien

    2016-08-01

    The adaptive optics (AO) assisted CRIRES instrument is an IR (0.92 - 5.2 μm) high-resolution spectrograph was in operation from 2006 to 2014 at the Very Large Telescope (VLT) observatory. CRIRES was a unique instrument, accessing a parameter space (wavelength range and spectral resolution) up to now largely uncharted. It consisted of a single-order spectrograph providing long-slit (40 arcsecond) spectroscopy with a resolving power up to R=100 000. However the setup was limited to a narrow, single-shot, spectral range of about 1/70 of the central wavelength, resulting in low observing efficiency for many scientific programmes requiring a broad spectral coverage. The CRIRES upgrade project, CRIRES+, transforms this VLT instrument into a cross-dispersed spectrograph to increase the simultaneously covered wavelength range by a factor of ten. A new and larger detector focal plane array of three Hawaii 2RG detectors with 5.3 μm cut-off wavelength will replace the existing detectors. For advanced wavelength calibration, custom-made absorption gas cells and an etalon system will be added. A spectro-polarimetric unit will allow the recording of circular and linear polarized spectra. This upgrade will be supported by dedicated data reduction software allowing the community to take full advantage of the new capabilities offered by CRIRES+. CRIRES+ has now entered its assembly and integration phase and will return with all new capabilities by the beginning of 2018 to the Very Large Telescope in Chile. This article will provide the reader with an update of the current status of the instrument as well as the remaining steps until final installation at the Paranal Observatory.

  2. TIMASSS: the IRAS 16293-2422 millimeter and submillimeter spectral survey. I. Observations, calibration, and analysis of the line kinematics

    NARCIS (Netherlands)

    Caux, E.; Kahane, C.; Castets, A.; Coutens, A.; Ceccarelli, C.; Bacmann, A.; Bisschop, S.; Bottinelli, S.; Comito, C.; Helmich, F. P.; Lefloch, B.; Parise, B.; Schilke, P.; Tielens, A. G. G. M.; van Dishoeck, E.; Vastel, C.; Wakelam, V.; Walters, A.

    Context. Unbiased spectral surveys are powerful tools to study the chemistry and the physics of star forming regions, because they can provide a complete census of the molecular content and the observed lines probe the physical structure of the source. Aims. While unbiased surveys at the millimeter

  3. Convex relaxations of spectral sparsity for robust super-resolution and line spectrum estimation

    Science.gov (United States)

    Chi, Yuejie

    2017-08-01

    We consider recovering the amplitudes and locations of spikes in a point source signal from its low-pass spectrum that may suffer from missing data and arbitrary outliers. We first review and provide a unified view of several recently proposed convex relaxations that characterize and capitalize the spectral sparsity of the point source signal without discretization under the framework of atomic norms. Next we propose a new algorithm when the spikes are known a priori to be positive, motivated by applications such as neural spike sorting and fluorescence microscopy imaging. Numerical experiments are provided to demonstrate the effectiveness of the proposed approach.

  4. High-resolution 3-μm spectra of Jupiter: Latitudinal spectral variations influenced by molecules, clouds, and haze

    Science.gov (United States)

    Kim, Sang J.; Geballe, T. R.; Kim, J. H.; Jung, A.; Seo, H. J.; Minh, Y. C.

    2010-08-01

    We present latitudinally-resolved high-resolution ( R = 37,000) pole-to-pole spectra of Jupiter in various narrow longitudinal ranges, in spectral intervals covering roughly half of the spectral range 2.86-3.53 μm. We have analyzed the data with the aid of synthetic spectra generated from a model jovian atmosphere that included lines of CH 4, CH 3D, NH 3, C 2H 2, C 2H 6, PH 3, and HCN, as well as clouds and haze. Numerous spectral features of many of these molecular species are present and are individually identified for the first time, as are many lines of H3+ and a few unidentified spectral features. In both polar regions the 2.86-3.10-μm continuum is more than 10 times weaker than in spectra at lower latitudes, implying that in this wavelength range the single-scattering albedos of polar haze particles are very low. In contrast, the 3.24-3.53 μm the weak polar and equatorial continua are of comparable intensity. We derive vertical distributions of NH 3, C 2H 2 and C 2H 6, and find that the mixing ratios of NH 3 and C 2H 6 show little variation between equatorial and polar regions. However, the mixing ratios of C 2H 2 in the northern and southern polar regions are ˜6 and ˜3 times, respectively, less than those in the equatorial regions. The derived mixing ratio curves of C 2H 2 and C 2H 6 extend up to the 10 -6 bar level, a significantly higher altitude than most previous results in the literature. Further ground-based observations covering other longitudes are needed to test if these mixing ratios are representative values for the equatorial and polar regions.

  5. Enhanced spectral resolution by high-dimensional NMR using the filter diagonalization method and "hidden" dimensions.

    Science.gov (United States)

    Meng, Xi; Nguyen, Bao D; Ridge, Clark; Shaka, A J

    2009-01-01

    High-dimensional (HD) NMR spectra have poorer digital resolution than low-dimensional (LD) spectra, for a fixed amount of experiment time. This has led to "reduced-dimensionality" strategies, in which several LD projections of the HD NMR spectrum are acquired, each with higher digital resolution; an approximate HD spectrum is then inferred by some means. We propose a strategy that moves in the opposite direction, by adding more time dimensions to increase the information content of the data set, even if only a very sparse time grid is used in each dimension. The full HD time-domain data can be analyzed by the filter diagonalization method (FDM), yielding very narrow resonances along all of the frequency axes, even those with sparse sampling. Integrating over the added dimensions of HD FDM NMR spectra reconstitutes LD spectra with enhanced resolution, often more quickly than direct acquisition of the LD spectrum with a larger number of grid points in each of the fewer dimensions. If the extra-dimensions do not appear in the final spectrum, and are used solely to boost information content, we propose the moniker hidden-dimension NMR. This work shows that HD peaks have unmistakable frequency signatures that can be detected as single HD objects by an appropriate algorithm, even though their patterns would be tricky for a human operator to visualize or recognize, and even if digital resolution in an HD FT spectrum is very coarse compared with natural line widths.

  6. Using Airborne High Spectral Resolution Lidar Data to Evaluate Combined Active Plus Passive Retrievals of Aerosol Extinction Profiles

    Science.gov (United States)

    Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Kittaka, C.; Vaughn, M. A.; Remer, L. A.

    2010-01-01

    We derive aerosol extinction profiles from airborne and space-based lidar backscatter signals by constraining the retrieval with column aerosol optical thickness (AOT), with no need to rely on assumptions about aerosol type or lidar ratio. The backscatter data were acquired by the NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL) and by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. The HSRL also simultaneously measures aerosol extinction coefficients independently using the high spectral resolution lidar technique, thereby providing an ideal data set for evaluating the retrieval. We retrieve aerosol extinction profiles from both HSRL and CALIOP attenuated backscatter data constrained with HSRL, Moderate-Resolution Imaging Spectroradiometer (MODIS), and Multiangle Imaging Spectroradiometer column AOT. The resulting profiles are compared with the aerosol extinction measured by HSRL. Retrievals are limited to cases where the column aerosol thickness is greater than 0.2 over land and 0.15 over water. In the case of large AOT, the results using the Aqua MODIS constraint over water are poorer than Aqua MODIS over land or Terra MODIS. The poorer results relate to an apparent bias in Aqua MODIS AOT over water observed in August 2007. This apparent bias is still under investigation. Finally, aerosol extinction coefficients are derived from CALIPSO backscatter data using AOT from Aqua MODIS for 28 profiles over land and 9 over water. They agree with coincident measurements by the airborne HSRL to within +/-0.016/km +/- 20% for at least two-thirds of land points and within +/-0.028/km +/- 20% for at least two-thirds of ocean points.

  7. High resolution shear wave reflection surveying for hydrogeological investigations

    International Nuclear Information System (INIS)

    Johnson, W.J.; Clark, J.C.

    1992-08-01

    The high resolution S-wave method has been developed to be a powerful tool in mapping subsurface lithology and in conducting groundwater investigations. The research has demonstrated that the resolution obtainable using S-waves in a Coastal Plain environment is more than double than that obtained using conventional reflection, which already offers a higher resolution than any other surface method. Where the mapping of thin clay layers functioning as aquitards or thin sand layers functioning as aquifers are critical to the understanding of groundwater flow, S-wave reflections offer unparalleled possibilities for nondestructive exploration. The field experiment at Cooke Crossroads, South Carolina enabled the detection and mapping of beds in the thickness range of one to three feet. The S-wave reflection technique, in combination with conventional P-wave reflection, has potential to directly detect confined and unconfined aquifers. This is a breakthrough technology that still requires additional research before it can be applied on a commercial basis. Aquifer systems were interpreted from the test data at Cooke Crossroads consistent with theoretical model. Additional research is need in assessing the theoretical response of P- and S-waves to subsurface interfaces within unconsolidated sediments of varying moisture content and lithology. More theoretical modeling and in situ testing are needed to bring our knowledge of these phenomena to the level that oil and gas researchers have done for fluids in sandstones

  8. Kite aerial photography for low-cost, ultra-high spatial resolution multi-spectral mapping of intertidal landscapes.

    Directory of Open Access Journals (Sweden)

    Mitch Bryson

    Full Text Available Intertidal ecosystems have primarily been studied using field-based sampling; remote sensing offers the ability to collect data over large areas in a snapshot of time that could complement field-based sampling methods by extrapolating them into the wider spatial and temporal context. Conventional remote sensing tools (such as satellite and aircraft imaging provide data at limited spatial and temporal resolutions and relatively high costs for small-scale environmental science and ecologically-focussed studies. In this paper, we describe a low-cost, kite-based imaging system and photogrammetric/mapping procedure that was developed for constructing high-resolution, three-dimensional, multi-spectral terrain models of intertidal rocky shores. The processing procedure uses automatic image feature detection and matching, structure-from-motion and photo-textured terrain surface reconstruction algorithms that require minimal human input and only a small number of ground control points and allow the use of cheap, consumer-grade digital cameras. The resulting maps combine imagery at visible and near-infrared wavelengths and topographic information at sub-centimeter resolutions over an intertidal shoreline 200 m long, thus enabling spatial properties of the intertidal environment to be determined across a hierarchy of spatial scales. Results of the system are presented for an intertidal rocky shore at Jervis Bay, New South Wales, Australia. Potential uses of this technique include mapping of plant (micro- and macro-algae and animal (e.g. gastropods assemblages at multiple spatial and temporal scales.

  9. Kite aerial photography for low-cost, ultra-high spatial resolution multi-spectral mapping of intertidal landscapes.

    Science.gov (United States)

    Bryson, Mitch; Johnson-Roberson, Matthew; Murphy, Richard J; Bongiorno, Daniel

    2013-01-01

    Intertidal ecosystems have primarily been studied using field-based sampling; remote sensing offers the ability to collect data over large areas in a snapshot of time that could complement field-based sampling methods by extrapolating them into the wider spatial and temporal context. Conventional remote sensing tools (such as satellite and aircraft imaging) provide data at limited spatial and temporal resolutions and relatively high costs for small-scale environmental science and ecologically-focussed studies. In this paper, we describe a low-cost, kite-based imaging system and photogrammetric/mapping procedure that was developed for constructing high-resolution, three-dimensional, multi-spectral terrain models of intertidal rocky shores. The processing procedure uses automatic image feature detection and matching, structure-from-motion and photo-textured terrain surface reconstruction algorithms that require minimal human input and only a small number of ground control points and allow the use of cheap, consumer-grade digital cameras. The resulting maps combine imagery at visible and near-infrared wavelengths and topographic information at sub-centimeter resolutions over an intertidal shoreline 200 m long, thus enabling spatial properties of the intertidal environment to be determined across a hierarchy of spatial scales. Results of the system are presented for an intertidal rocky shore at Jervis Bay, New South Wales, Australia. Potential uses of this technique include mapping of plant (micro- and macro-algae) and animal (e.g. gastropods) assemblages at multiple spatial and temporal scales.

  10. Searching for a Differentiated Asteroid Family: A Spectral Survey of the Massalia, Merxia, and Agnia Families

    Science.gov (United States)

    Thomas, Cristina A.; Moskovitz, Nicholas; Lim, Lucy F.; Trilling, David E.

    2017-10-01

    Asteroid families were formed by catastrophic collisions or large cratering events that caused fragmentation of the parent body and ejection of asteroidal fragments with velocities sufficient to prevent re-accretion. Due to these formation processes, asteroid families provide us with the opportunity to probe the interiors of the former parent bodies. Differentiation of a large initially chondritic parent body is expected to result in an “onion shell" object with an iron-nickel core, a thick olivine-dominated mantle, and a thin plagioclase/pyroxene crust. However, most asteroid families tend to show similar spectra (and therefore composition) among the members. Spectroscopic studies have observed a paucity of metal-like materials and olivine-dominated assemblages within Main Belt asteroid families.The deficit of olivine-rich mantle material in the meteorite record and in asteroid observations is known as the “Missing Mantle" problem. For years the best explanation has been the “battered to bits" hypothesis: differentiated parent bodies (aside from Vesta) were disrupted very early in the Solar System and the olivine-rich material was collisionally broken down over time. Alternatively, Elkins-Tanton et al. (2013) have suggested that previous work has overestimated the amount of olivine produced by the differentiation of a chondritic parent body.We have completed a visible and near-infrared wavelength spectral survey of asteroids in the Massalia, Merxia, and Agnia S-type Main Belt asteroid families. These families were carefully chosen for the spectroscopic survey because they have compositions most closely associated with a history of thermal metamorphism and because they represent a range of collisional formation scenarios. Additionally, members of the Merxia and Agnia families were identified as products of differentiation by Sunshine et al. (2004).Our spectral analyses suggest that the observed families contain products of partial differentiation. We will

  11. High resolution Thomson Parabola Spectrometer for full spectral capture of multi-species ion beams

    International Nuclear Information System (INIS)

    Alejo, A.; Kar, S.; Ahmed, H.; Doria, D.; Borghesi, M.; Tebartz, A.; Ding, J.; Neumann, N.; Astbury, S.; Carroll, D. C.; Scott, G. G.; Higginson, A.; McKenna, P.; Wagner, F.; Roth, M.

    2016-01-01

    We report on the experimental characterisation of laser-driven ion beams using a Thomson Parabola Spectrometer (TPS) equipped with trapezoidally shaped electric plates, proposed by Gwynne et al. [Rev. Sci. Instrum. 85, 033304 (2014)]. While a pair of extended (30 cm long) electric plates was able to produce a significant increase in the separation between neighbouring ion species at high energies, deploying a trapezoidal design circumvented the spectral clipping at the low energy end of the ion spectra. The shape of the electric plate was chosen carefully considering, for the given spectrometer configuration, the range of detectable ion energies and species. Analytical tracing of the ion parabolas matches closely with the experimental data, which suggests a minimal effect of fringe fields on the escaping ions close to the wedged edge of the electrode. The analytical formulae were derived considering the relativistic correction required for the high energy ions to be characterised using such spectrometer.

  12. High resolution Thomson Parabola Spectrometer for full spectral capture of multi-species ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Alejo, A.; Kar, S., E-mail: s.kar@qub.ac.uk; Ahmed, H.; Doria, D.; Borghesi, M. [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Tebartz, A.; Ding, J.; Neumann, N. [Institut für Kernphysik, Technische Universität Darmstadt, Schloßgartenstrasse 9, D-64289 Darmstadt (Germany); Astbury, S.; Carroll, D. C.; Scott, G. G. [Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX (United Kingdom); Higginson, A.; McKenna, P. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Wagner, F. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Roth, M. [Institut für Kernphysik, Technische Universität Darmstadt, Schloßgartenstraße 9, D-64289 Darmstadt (Germany)

    2016-08-15

    We report on the experimental characterisation of laser-driven ion beams using a Thomson Parabola Spectrometer (TPS) equipped with trapezoidally shaped electric plates, proposed by Gwynne et al. [Rev. Sci. Instrum. 85, 033304 (2014)]. While a pair of extended (30 cm long) electric plates was able to produce a significant increase in the separation between neighbouring ion species at high energies, deploying a trapezoidal design circumvented the spectral clipping at the low energy end of the ion spectra. The shape of the electric plate was chosen carefully considering, for the given spectrometer configuration, the range of detectable ion energies and species. Analytical tracing of the ion parabolas matches closely with the experimental data, which suggests a minimal effect of fringe fields on the escaping ions close to the wedged edge of the electrode. The analytical formulae were derived considering the relativistic correction required for the high energy ions to be characterised using such spectrometer.

  13. High resolution Thomson Parabola Spectrometer for full spectral capture of multi-species ion beams

    Science.gov (United States)

    Alejo, A.; Kar, S.; Tebartz, A.; Ahmed, H.; Astbury, S.; Carroll, D. C.; Ding, J.; Doria, D.; Higginson, A.; McKenna, P.; Neumann, N.; Scott, G. G.; Wagner, F.; Roth, M.; Borghesi, M.

    2016-08-01

    We report on the experimental characterisation of laser-driven ion beams using a Thomson Parabola Spectrometer (TPS) equipped with trapezoidally shaped electric plates, proposed by Gwynne et al. [Rev. Sci. Instrum. 85, 033304 (2014)]. While a pair of extended (30 cm long) electric plates was able to produce a significant increase in the separation between neighbouring ion species at high energies, deploying a trapezoidal design circumvented the spectral clipping at the low energy end of the ion spectra. The shape of the electric plate was chosen carefully considering, for the given spectrometer configuration, the range of detectable ion energies and species. Analytical tracing of the ion parabolas matches closely with the experimental data, which suggests a minimal effect of fringe fields on the escaping ions close to the wedged edge of the electrode. The analytical formulae were derived considering the relativistic correction required for the high energy ions to be characterised using such spectrometer.

  14. Herschel observations of extraordinary sources: Analysis of the HIFI 1.2 THz wide spectral survey toward orion KL. I. method

    Energy Technology Data Exchange (ETDEWEB)

    Crockett, Nathan R.; Bergin, Edwin A.; Neill, Justin L.; Favre, Cécile [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Schilke, Peter [Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln (Germany); Lis, Dariusz C.; Emprechtinger, Martin; Phillips, Thomas G. [Cahill Center for Astronomy and Astrophysics 301-17, California Institute of Technology, Pasadena, CA 91125 (United States); Bell, Tom A.; Cernicharo, José; Esplugues, Gisela B. [Centro de Astrobiología (CSIC/INTA), Laboratiorio de Astrofísica Molecular, Ctra. de Torrejón a Ajalvir, km 4, E-28850 Torrejón de Ardoz, Madrid (Spain); Blake, Geoffrey; Kleshcheva, Maria [Division of Geological and Planetary Sciences, California Institute of Technology, MS 150-21, Pasadena, CA 91125 (United States); Gupta, Harshal; Pearson, John [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Lord, Steven [Infrared Processing and Analysis Center, California Institute of Technology, MS 100-22, Pasadena, CA 91125 (United States); Marcelino, Nuria [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); McGuire, Brett A. [Division of Chemistry and Chemical Engineering, California Institute of Technology Pasadena, CA 91125 (United States); Plume, Rene [Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4 (Canada); Van der Tak, Floris [SRON Netherlands Institute for Space Research, P.O. Box 800, 9700 AV Groningen (Netherlands); and others

    2014-06-01

    We present a comprehensive analysis of a broadband spectral line survey of the Orion Kleinmann-Low nebula (Orion KL), one of the most chemically rich regions in the Galaxy, using the HIFI instrument on board the Herschel Space Observatory. This survey spans a frequency range from 480 to 1907 GHz at a resolution of 1.1 MHz. These observations thus encompass the largest spectral coverage ever obtained toward this high-mass star-forming region in the submillimeter with high spectral resolution and include frequencies >1 THz, where the Earth's atmosphere prevents observations from the ground. In all, we detect emission from 39 molecules (79 isotopologues). Combining this data set with ground-based millimeter spectroscopy obtained with the IRAM 30 m telescope, we model the molecular emission from the millimeter to the far-IR using the XCLASS program, which assumes local thermodynamic equilibrium (LTE). Several molecules are also modeled with the MADEX non-LTE code. Because of the wide frequency coverage, our models are constrained by transitions over an unprecedented range in excitation energy. A reduced χ{sup 2} analysis indicates that models for most species reproduce the observed emission well. In particular, most complex organics are well fit by LTE implying gas densities are high (>10{sup 6} cm{sup –3}) and excitation temperatures and column densities are well constrained. Molecular abundances are computed using H{sub 2} column densities also derived from the HIFI survey. The distribution of rotation temperatures, T {sub rot}, for molecules detected toward the hot core is significantly wider than the compact ridge, plateau, and extended ridge T {sub rot} distributions, indicating the hot core has the most complex thermal structure.

  15. A sample of galaxy pairs identified from the LAMOST spectral survey and the Sloan Digital Sky Survey

    International Nuclear Information System (INIS)

    Shen, Shi-Yin; Argudo-Fernández, Maria; Chen, Li; Feng, Shuai; Hou, Jin-Liang; Shao, Zheng-Yi; Chen, Xiao-Yan; Luo, A-Li; Wu, Hong; Yang, Hai-Feng; Yang, Ming; Hou, Yong-Hui; Wang, Yue-Fei; Jiang, Peng; Wang, Ting-Gui; Jing, Yi-Peng; Kong, Xu; Wang, Wen-Ting; Luo, Zhi-Jian; Wu, Xue-Bing

    2016-01-01

    A small fraction (< 10%) of the SDSS main galaxy (MG) sample has not been targeted with spectroscopy due to the effect of fiber collisions. These galaxies have been compiled into the input catalog of the LAMOST ExtraGAlactic Surveys and named the complementary galaxy sample. In this paper, we introduce this project and status of the spectroscopies associated with the complementary galaxies in the first two years of the LAMOST spectral survey (till Sep. of 2014). Moreover, we present a sample of 1102 galaxy pairs identified from the LAMOST complementary galaxies and SDSS MGs, which are defined as two members that have a projected distance smaller than 100 h −1 70 kpc and a recessional velocity difference smaller than 500 km s −1 . Compared with galaxy pairs that are only selected from SDSS, the LAMOST-SDSS pairs have the advantages of not being biased toward large separations and therefore act as a useful supplement in statistical studies of galaxy interaction and galaxy merging. (paper)

  16. An Interferometric Spectral-Line and Imaging Survey of VY Canis Majoris in the 345 GHz Band

    OpenAIRE

    Kaminski, T.; Gottlieb, C. A.; Young, K. H.; Menten, K. M.; Patel, N. A.

    2013-01-01

    A spectral line survey of the oxygen-rich red supergiant VY Canis Majoris was made between 279 and 355 GHz with the Submillimeter Array. Two hundred twenty three spectral features from 19 molecules (not counting isotopic species of some of them) were observed, including the rotational spectra of TiO, TiO2, and AlCl for the first time in this source. The parameters and an atlas of all spectral features is presented. Observations of each line with a synthesized beam of ~0.9 arcsec, reveal the c...

  17. High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

    Science.gov (United States)

    Ginzburg, Boris; Cohen, Tsuriel Ram; Zafrir, Hovav; Alimi, Roger; Salomonski, Nizan; Sharvit, Jacob

    2007-01-01

    The purpose of this paper is to present a system developed for detection and accurate mapping of ferro-metallic objects buried below the seabed in shallow waters. The system comprises a precise magnetic gradiometer and navigation subsystem, both installed on a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition we present the results of a marine survey of a near-shore area in the vicinity of Atlit, a town situated on the Mediterranean coast of Israel, about 15 km south of Haifa. The primary purpose of the survey was to search for a Harvard airplane that crashed into the sea in 1960. A magnetic map of the survey area (3.5 km2 on a 0.5 m grid) was created revealing the anomalies at sub-meter accuracy. For each investigated target location a corresponding ferro-metallic item was dug out, one of which turned to be very similar to a part of the crashed airplane. The accuracy of location was confirmed by matching the position of the actual dug artifacts with the magnetic map within a range of ± 1 m, in a water depth of 9 m. PMID:28903191

  18. High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

    Directory of Open Access Journals (Sweden)

    Jacob Sharvit

    2007-09-01

    Full Text Available The purpose of this paper is to present a system developed for detection andaccurate mapping of ferro-metallic objects buried below the seabed in shallow waters. Thesystem comprises a precise magnetic gradiometer and navigation subsystem, both installedon a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition wepresent the results of a marine survey of a near-shore area in the vicinity of Atlit, a townsituated on the Mediterranean coast of Israel, about 15 km south of Haifa. The primarypurpose of the survey was to search for a Harvard airplane that crashed into the sea in 1960.A magnetic map of the survey area (3.5 km2 on a 0.5 m grid was created revealing theanomalies at sub-meter accuracy. For each investigated target location a correspondingferro-metallic item was dug out, one of which turned to be very similar to a part of thecrashed airplane. The accuracy of location was confirmed by matching the position of theactual dug artifacts with the magnetic map within a range of ± 1 m, in a water depth of 9 m.

  19. Spatial resolution dependence on spectral frequency in human speech cortex electrocorticography

    Science.gov (United States)

    Muller, Leah; Hamilton, Liberty S.; Edwards, Erik; Bouchard, Kristofer E.; Chang, Edward F.

    2016-10-01

    Objective. Electrocorticography (ECoG) has become an important tool in human neuroscience and has tremendous potential for emerging applications in neural interface technology. Electrode array design parameters are outstanding issues for both research and clinical applications, and these parameters depend critically on the nature of the neural signals to be recorded. Here, we investigate the functional spatial resolution of neural signals recorded at the human cortical surface. We empirically derive spatial spread functions to quantify the shared neural activity for each frequency band of the electrocorticogram. Approach. Five subjects with high-density (4 mm center-to-center spacing) ECoG grid implants participated in speech perception and production tasks while neural activity was recorded from the speech cortex, including superior temporal gyrus, precentral gyrus, and postcentral gyrus. The cortical surface field potential was decomposed into traditional EEG frequency bands. Signal similarity between electrode pairs for each frequency band was quantified using a Pearson correlation coefficient. Main results. The correlation of neural activity between electrode pairs was inversely related to the distance between the electrodes; this relationship was used to quantify spatial falloff functions for cortical subdomains. As expected, lower frequencies remained correlated over larger distances than higher frequencies. However, both the envelope and phase of gamma and high gamma frequencies (30-150 Hz) are largely uncorrelated (<90%) at 4 mm, the smallest spacing of the high-density arrays. Thus, ECoG arrays smaller than 4 mm have significant promise for increasing signal resolution at high frequencies, whereas less additional gain is achieved for lower frequencies. Significance. Our findings quantitatively demonstrate the dependence of ECoG spatial resolution on the neural frequency of interest. We demonstrate that this relationship is consistent across patients and

  20. The inference of vector magnetic fields from polarization measurements with limited spectral resolution

    Science.gov (United States)

    Lites, B. W.; Skumanich, A.

    1985-01-01

    A method is presented for recovery of the vector magnetic field and thermodynamic parameters from polarization measurement of photospheric line profiles measured with filtergraphs. The method includes magneto-optic effects and may be utilized on data sampled at arbitrary wavelengths within the line profile. The accuracy of this method is explored through inversion of synthetic Stokes profiles subjected to varying levels of random noise, instrumental wave-length resolution, and line profile sampling. The level of error introduced by the systematic effect of profile sampling over a finite fraction of the 5 minute oscillation cycle is also investigated. The results presented here are intended to guide instrumental design and observational procedure.

  1. Automated work-flow for processing high-resolution direct infusion electrospray ionization mass spectral fingerprints

    DEFF Research Database (Denmark)

    Hansen, Michael Adsetts Edberg; Smedsgaard, Jørn

    2007-01-01

    an automated data processing pipeline to compare large numbers of fingerprint spectra from direct infusion experiments analyzed by high resolution MS. We describe some of the intriguing problems that have to be addressed. starting with the conversion and pre-processing of the raw data to the final data......The use of mass spectrometry (MS) is pivotal in analyses of the metabolome and presents a major challenge for subsequent data processing. While the last few years have given new high performance instruments, there has not been a comparable development in data processing. In this paper we discuss...

  2. Simulation of heat and mass transfer in turbulent channel flow using the spectral-element method: effect of spatial resolution

    Science.gov (United States)

    Ryzhenkov, V.; Ivashchenko, V.; Vinuesa, R.; Mullyadzhanov, R.

    2016-10-01

    We use the open-source code nek5000 to assess the accuracy of high-order spectral element large-eddy simulations (LES) of a turbulent channel flow depending on the spatial resolution compared to the direct numerical simulation (DNS). The Reynolds number Re = 6800 is considered based on the bulk velocity and half-width of the channel. The filtered governing equations are closed with the dynamic Smagorinsky model for subgrid stresses and heat flux. The results show very good agreement between LES and DNS for time-averaged velocity and temperature profiles and their fluctuations. Even the coarse LES grid which contains around 30 times less points than the DNS one provided predictions of the friction velocity within 2.0% accuracy interval.

  3. A postprocessing method based on high-resolution spectral estimation for FDTD calculation of phononic band structures

    Energy Technology Data Exchange (ETDEWEB)

    Su Xiaoxing, E-mail: xxsu@bjtu.edu.c [School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044 (China); Li Jianbao; Wang Yuesheng [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China)

    2010-05-15

    If the energy bands of a phononic crystal are calculated by the finite difference time domain (FDTD) method combined with the fast Fourier transform (FFT), good estimation of the eigenfrequencies can only be ensured by the postprocessing of sufficiently long time series generated by a large number of FDTD iterations. In this paper, a postprocessing method based on the high-resolution spectral estimation via the Yule-Walker method is proposed to overcome this difficulty. Numerical simulation results for three-dimensional acoustic and two-dimensional elastic systems show that, compared with the classic FFT-based postprocessing method, the proposed method can give much better estimation of the eigenfrequencies when the FDTD is run with relatively few iterations.

  4. A postprocessing method based on high-resolution spectral estimation for FDTD calculation of phononic band structures

    International Nuclear Information System (INIS)

    Su Xiaoxing; Li Jianbao; Wang Yuesheng

    2010-01-01

    If the energy bands of a phononic crystal are calculated by the finite difference time domain (FDTD) method combined with the fast Fourier transform (FFT), good estimation of the eigenfrequencies can only be ensured by the postprocessing of sufficiently long time series generated by a large number of FDTD iterations. In this paper, a postprocessing method based on the high-resolution spectral estimation via the Yule-Walker method is proposed to overcome this difficulty. Numerical simulation results for three-dimensional acoustic and two-dimensional elastic systems show that, compared with the classic FFT-based postprocessing method, the proposed method can give much better estimation of the eigenfrequencies when the FDTD is run with relatively few iterations.

  5. High-resolution measurements and multichannel quantum defect analysis of spectral line shapes of autoionizing Rydberg series

    International Nuclear Information System (INIS)

    Ueda, Kiyoshi

    1997-01-01

    Spectral line shapes for autoionizing Rydberg series are briefly reviewed within the framework of multichannel quantum defect theory (MQDT). Recent high-resolution measurements and MQDT analysis for the spectra line shapes are reviewed for the mp 5 ( 2 P 1/2 )ns ' and nd ' J=1 odd spectra of the Ar, Kr, and Xe atoms (m=3,4,5 for Ar, Kr, and Xe) and the 3p 5 ( 2 P 1/2 )nd ' J=2 and 3 odd spectra of Ar*3p 5 4p excited atoms. Some results are also discussed for the Ca 4p( 2 P 1/2,3/2 )ns and nd J=1 odd spectrum and the Ba 5d( 2 P 5/2 )nd J=1 odd spectrum

  6. High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

    OpenAIRE

    Jacob Sharvit; Nizan Salomonski; Roger Alimi; Hovav Zafrir; Tsuriel Ram Cohen; Boris Ginzburg; Eyal Weiss

    2007-01-01

    The purpose of this paper is to present a system developed for detection andaccurate mapping of ferro-metallic objects buried below the seabed in shallow waters. Thesystem comprises a precise magnetic gradiometer and navigation subsystem, both installedon a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition wepresent the results of a marine survey of a near-shore area in the vicinity of Atlit, a townsituated on the Mediterranean coast of Israel, about 15 km south of ...

  7. High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

    OpenAIRE

    Weiss, Eyal; Ginzburg, Boris; Cohen, Tsuriel Ram; Zafrir, Hovav; Alimi, Roger; Salomonski, Nizan; Sharvit, Jacob

    2007-01-01

    The purpose of this paper is to present a system developed for detection and accurate mapping of ferro-metallic objects buried below the seabed in shallow waters. The system comprises a precise magnetic gradiometer and navigation subsystem, both installed on a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition we present the results of a marine survey of a near-shore area in the vicinity of Atlit, a town situated on the Mediterranean coast of Israel, about 15 km sout...

  8. Identification of triacylglycerol using automated annotation of high resolution multistage mass spectral trees.

    Science.gov (United States)

    Wang, Xiupin; Peng, Qingzhi; Li, Peiwu; Zhang, Qi; Ding, Xiaoxia; Zhang, Wen; Zhang, Liangxiao

    2016-10-12

    High complexity of identification for non-target triacylglycerols (TAGs) is a major challenge in lipidomics analysis. To identify non-target TAGs, a powerful tool named accurate MS(n) spectrometry generating so-called ion trees is used. In this paper, we presented a technique for efficient structural elucidation of TAGs on MS(n) spectral trees produced by LTQ Orbitrap MS(n), which was implemented as an open source software package, or TIT. The TIT software was used to support automatic annotation of non-target TAGs on MS(n) ion trees from a self-built fragment ion database. This database includes 19108 simulate TAG molecules from a random combination of fatty acids and corresponding 500582 self-built multistage fragment ions (MS ≤ 3). Our software can identify TAGs using a "stage-by-stage elimination" strategy. By utilizing the MS(1) accurate mass and referenced RKMD, the TIT software can discriminate unique elemental composition candidates. The regiospecific isomers of fatty acyl chains will be distinguished using MS(2) and MS(3) fragment spectra. We applied the algorithm to the selection of 45 TAG standards and demonstrated that the molecular ions could be 100% correctly assigned. Therefore, the TIT software could be applied to TAG identification in complex biological samples such as mouse plasma extracts. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Advanced mineral and lithological mapping using high spectral resolution TIR data from the active CO2 remote sensing system; CO2 laser wo mochiita kosupekutoru bunkaino netsusekigai remote sensing data no ganseki kobutsu shikibetsu eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    Okada, K [Sumitomo Metal Mining Co. Ltd., Osaka (Japan); Hato, M [Earth Remote Sensing Data Analysis Center, Tokyo (Japan); Cudahy, T; Tapley, I

    1997-05-27

    A study was conducted on rock/mineral mapping technology for the metal ore deposit survey using MIRACO2LAS, an active type thermal infrared ray remote sensing system which was developed by CSIRO of Australia and is now the highest in spectral resolution in the world, and TIMS of NASA which is a passive type system. The area for the survey is the area of Olary/Broken Hill and Mt. Fitton of Australia. A good correlation is seen between the ground reflectance measured by MIRACO2LAS and the value measured by the chamber CO2 laser of rocks sampled at the above-mentioned area. In case that the width of spectral characteristics is below 300nm, the inspection ability by MIRACO2LAS`s high spectral resolution is more determined in mineral mapping as compared with TIMS which is large in band width. Minerals mapped using MIRACO2LAS are quartz, talc, amphibole, hornblende, garnet, supessartine, dolomite, magnesite, etc. 4 refs., 3 figs.

  10. Molecular-cloud-scale Chemical Composition. II. Mapping Spectral Line Survey toward W3(OH) in the 3 mm Band

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Yuri [Institute of Astronomy, The University of Tokyo, 2-21-1, Osawa, Mitaka, Tokyo 181-0015 (Japan); Watanabe, Yoshimasa; Yamamoto, Satoshi [Department of Physics, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Harada, Nanase [Academia Sinica Institute of Astronomy and Astrophysics, No.1, Sec. 4, Roosevelt Road, 10617 Taipei, Taiwan, R.O.C. (China); Shimonishi, Takashi [Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aramakiazaaoba 6-3, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Sakai, Nami [RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aikawa, Yuri [Department of Astronomy, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kawamura, Akiko [Chile Observatory, National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2017-10-10

    To study a molecular-cloud-scale chemical composition, we conducted a mapping spectral line survey toward the Galactic molecular cloud W3(OH), which is one of the most active star-forming regions in the Perseus arm. We conducted our survey through the use of the Nobeyama Radio Observatory 45 m telescope, and observed the area of 16′ × 16′, which corresponds to 9.0 pc × 9.0 pc. The observed frequency ranges are 87–91, 96–103, and 108–112 GHz. We prepared the spectrum averaged over the observed area, in which eight molecular species (CCH, HCN, HCO{sup +}, HNC, CS, SO, C{sup 18}O, and {sup 13}CO) are identified. On the other hand, the spectrum of the W3(OH) hot core observed at a 0.17 pc resolution shows the lines of various molecules such as OCS, H{sub 2}CS CH{sub 3}CCH, and CH{sub 3}CN in addition to the above species. In the spatially averaged spectrum, emission of the species concentrated just around the star-forming core, such as CH{sub 3}OH and HC{sub 3}N, is fainter than in the hot core spectrum, whereas emission of the species widely extended over the cloud such as CCH is relatively brighter. We classified the observed area into five subregions according to the integrated intensity of {sup 13}CO, and evaluated the contribution to the averaged spectrum from each subregion. The CCH, HCN, HCO{sup +}, and CS lines can be seen even in the spectrum of the subregion with the lowest {sup 13}CO integrated intensity range (<10 K km s{sup −1}). Thus, the contributions of the spatially extended emission is confirmed to be dominant in the spatially averaged spectrum.

  11. A non-LTE model for the Jovian methane infrared emissions at high spectral resolution

    Science.gov (United States)

    Halthore, Rangasayi N.; Allen, J. E., Jr.; Decola, Philip L.

    1994-01-01

    High resolution spectra of Jupiter in the 3.3 micrometer region have so far failed to reveal either the continuum or the line emissions that can be unambiguously attributed to the nu(sub 3) band of methane (Drossart et al. 1993; Kim et al. 1991). Nu(sub 3) line intensities predicted with the help of two simple non-Local Thermodynamic Equilibrium (LTE) models -- a two-level model and a three-level model, using experimentally determined relaxation coefficients, are shown to be one to three orders of magnitude respectively below the 3-sigma noise level of these observations. Predicted nu(sub 4) emission intensities are consistent with observed values. If the methane mixing ratio below the homopause is assumed as 2 x 10(exp -3), a value of about 300 K is derived as an upper limit to the temperature of the high stratosphere at microbar levels.

  12. Exploring graphene field effect transistor devices to improve spectral resolution of semiconductor radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Richard Karl [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Howell, Stephen Wayne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martin, Jeffrey B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hamilton, Allister B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-12-01

    Graphene, a planar, atomically thin form of carbon, has unique electrical and material properties that could enable new high performance semiconductor devices. Graphene could be of specific interest in the development of room-temperature, high-resolution semiconductor radiation spectrometers. Incorporating graphene into a field-effect transistor architecture could provide an extremely high sensitivity readout mechanism for sensing charge carriers in a semiconductor detector, thus enabling the fabrication of a sensitive radiation sensor. In addition, the field effect transistor architecture allows us to sense only a single charge carrier type, such as electrons. This is an advantage for room-temperature semiconductor radiation detectors, which often suffer from significant hole trapping. Here we report on initial efforts towards device fabrication and proof-of-concept testing. This work investigates the use of graphene transferred onto silicon and silicon carbide, and the response of these fabricated graphene field effect transistor devices to stimuli such as light and alpha radiation.

  13. Annealing as grown large volume CZT single crystals for increased spectral resolution

    International Nuclear Information System (INIS)

    Li, Longxia

    2008-01-01

    The spectroscopic performance of current large-volume Cadmium 10% Zinc Telluride, Cd 0.9 Zn 0.1 Te, (CZT) detectors is impaired by cumulative effect of tellurium precipitates (secondary phases) presented in CZT single-crystal grown by low-pressure Bridgman techniques(1). This statistical effect may limit the energy resolution of large-volume CZT detectors (typically 2-5% at 662 keV for 12-mm thick devices). The stochastic nature of the interaction prevents the use of any electronic or digital charge correction techniques without a significant reduction in the detector efficiency. This volume constraint hampers the utility of CZT since the detectors are inefficient at detecting photons >1MeV and/or in low fluency situations. During the project, seven runs CZT ingots have been grown, in these ingots the indium dopant concentrations have been changed in the range between 0.5ppm to 6ppm. The I-R mapping imaging method has been employed to study the Te-precipitates. The Teprecipitates in as-grown CZT wafers, and after annealing wafers have been systematically studied by using I-R mapping system (home installed, resolution of 1.5 (micro)m). We employed our I-R standard annealing CZT (Zn=4%) procedure or two-steps annealing into radiation CZT (Zn=10%), we achieved the 'non'-Te precipitates (size 10 9-10 (Omega)-cm. We believe that the Te-precipitates are the p-type defects, its reducing number causes the CZT became n+-type, therefore we varied or reduced the indium dapant concentration during the growth and changed the Te-precipitates size and density by using different Cd-temperature and different annealing procedures. We have made the comparisons among Te-precipitates size, density and Indium dopant concentrations, and we found that the CZT with smaller size of Te-precipitates is suitable for radiation uses but non-Te precipitates is impossible to be used in the radiation detectors, because the CZT would became un-dopant or 'intrinsic' with non radiation affection (we

  14. Moderate-resolution spectral standards from lambda 5600 to lambda 9000

    Science.gov (United States)

    Allen, Lori E.; Strom, Karen M.

    1995-01-01

    We present a grid of stellar classification spectra of moderate resolution (R approximately 1500) in the range lambda lambda 5600-9000 A, compiled from high signal-to noise spectra of 275 stars, most in the open clusters Praesepe and M67. The grid covers dwarfs from types B8 through M5, giants from G8 through M7, and subgiants from F5 through K0. We catalog atomic and molecular absorption features useful for stellar classification, and demonstrate the use of luminosity-sensitive features to distinguish between late-type dwarf and giant stars. The entire database is made available in digital format on anonymous ftp and through the World Wide Web.

  15. Spectral resolution and high-flux capability tradeoffs in CdTe detectors for clinical CT.

    Science.gov (United States)

    Hsieh, Scott S; Rajbhandary, Paurakh L; Pelc, Norbert J

    2018-04-01

    than the ideal photon counting detector. The optimal pixel size depends on a number of factors such as x-ray technique and object size. At high technique (140 kVp/500 mA), the ratio of variance for a 450 micron pixel compared to a 250 micron pixel size is 2126%, 200%, 97%, and 78% when imaging 10, 15, 20, and 25 cm of water, respectively. If 300 mg/cm 2 of iodine is also added to the object, the variance ratio is 117%, 91%, 74%, and 72%, respectively. Nonspectral tasks, such as equivalent monoenergetic imaging, are less sensitive to spectral distortion. The detector pixel size is an important design consideration in CdTe detectors. Smaller pixels allow for improved capabilities at high flux but increase charge sharing, which in turn compromises spectral performance. The optimal pixel size will depend on the specific task and on the charge shaping time. © 2018 American Association of Physicists in Medicine.

  16. SURVEY DESIGN FOR SPECTRAL ENERGY DISTRIBUTION FITTING: A FISHER MATRIX APPROACH

    International Nuclear Information System (INIS)

    Acquaviva, Viviana; Gawiser, Eric; Bickerton, Steven J.; Grogin, Norman A.; Guo Yicheng; Lee, Seong-Kook

    2012-01-01

    The spectral energy distribution (SED) of a galaxy contains information on the galaxy's physical properties, and multi-wavelength observations are needed in order to measure these properties via SED fitting. In planning these surveys, optimization of the resources is essential. The Fisher Matrix (FM) formalism can be used to quickly determine the best possible experimental setup to achieve the desired constraints on the SED-fitting parameters. However, because it relies on the assumption of a Gaussian likelihood function, it is in general less accurate than other slower techniques that reconstruct the probability distribution function (PDF) from the direct comparison between models and data. We compare the uncertainties on SED-fitting parameters predicted by the FM to the ones obtained using the more thorough PDF-fitting techniques. We use both simulated spectra and real data, and consider a large variety of target galaxies differing in redshift, mass, age, star formation history, dust content, and wavelength coverage. We find that the uncertainties reported by the two methods agree within a factor of two in the vast majority (∼90%) of cases. If the age determination is uncertain, the top-hat prior in age used in PDF fitting to prevent each galaxy from being older than the universe needs to be incorporated in the FM, at least approximately, before the two methods can be properly compared. We conclude that the FM is a useful tool for astronomical survey design.

  17. Simultaneous Confocal Scanning Laser Ophthalmoscopy Combined with High-Resolution Spectral-Domain Optical Coherence Tomography: A Review

    Directory of Open Access Journals (Sweden)

    Verônica Castro Lima

    2011-01-01

    Full Text Available We aimed to evaluate technical aspects and the clinical relevance of a simultaneous confocal scanning laser ophthalmoscope and a high-speed, high-resolution, spectral-domain optical coherence tomography (SDOCT device for retinal imaging. The principle of confocal scanning laser imaging provides a high resolution of retinal and choroidal vasculature with low light exposure. Enhanced contrast, details, and image sharpness are generated using confocality. The real-time SDOCT provides a new level of accuracy for assessment of the angiographic and morphological correlation. The combined system allows for simultaneous recordings of topographic and tomographic images with accurate correlation between them. Also it can provide simultaneous multimodal imaging of retinal pathologies, such as fluorescein and indocyanine green angiographies, infrared and blue reflectance (red-free images, fundus autofluorescence images, and OCT scans (Spectralis HRA + OCT; Heidelberg Engineering, Heidelberg, Germany. The combination of various macular diagnostic tools can lead to a better understanding and improved knowledge of macular diseases.

  18. Determination of channel temperature for AlGaN/GaN HEMTs by high spectral resolution micro-Raman spectroscopy

    International Nuclear Information System (INIS)

    Zhang Guangchen; Feng Shiwei; Li Jingwan; Guo Chunsheng; Zhao Yan

    2012-01-01

    Channel temperature determinations of AlGaN/GaN high electron mobility transistors (HEMTs) by high spectral resolution micro-Raman spectroscopy are proposed. The temperature dependence of the E2 phonon frequency of GaN material is calibrated by using a JYT-64000 micro-Raman system. By using the Lorentz fitting method, the measurement uncertainty for the Raman phonon frequency of ±0.035 cm −1 is achieved, corresponding to a temperature accuracy of ±3.2 °C for GaN material, which is the highest temperature resolution in the published works. The thermal resistance of the tested AlGaN/GaN HEMT sample is 22.8 °C/W, which is in reasonably good agreement with a three dimensional heat conduction simulation. The difference among the channel temperatures obtained by micro-Raman spectroscopy, the pulsed electrical method and the infrared image method are also investigated quantificationally. (semiconductor devices)

  19. INFRARED HIGH-RESOLUTION INTEGRATED LIGHT SPECTRAL ANALYSES OF M31 GLOBULAR CLUSTERS FROM APOGEE

    Energy Technology Data Exchange (ETDEWEB)

    Sakari, Charli M. [Department of Astronomy, University of Washington, Seattle WA 98195-1580 (United States); Shetrone, Matthew D. [McDonald Observatory, University of Texas at Austin, HC75 Box 1337-MCD, Fort Davis, TX 79734 (United States); Schiavon, Ricardo P. [Gemini Observatory, 670 N. A’Ohoku Place, Hilo, HI 96720 (United States); Bizyaev, Dmitry; Pan, Kaike [Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States); Prieto, Carlos Allende; García-Hernández, Domingo Aníbal [Instituto de Astrofísica de Canarias (IAC), Va Lactea s/n, E-38205 La Laguna, Tenerife (Spain); Beers, Timothy C. [Department of Physics and JINA Center for the Evolution of the Elements, University of Notre Dame, Notre Dame, IN 46556 (United States); Caldwell, Nelson [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lucatello, Sara [INAF Osservatorio Astronomico di Padova, Vicolo dellOsservatorio 5, I-35122 Padova (Italy); Majewski, Steven; O’Connell, Robert W. [Dept. of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Strader, Jay, E-mail: sakaricm@u.washington.edu [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2016-10-01

    Chemical abundances are presented for 25 M31 globular clusters (GCs), based on moderately high resolution ( R = 22,500) H -band integrated light (IL) spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE). Infrared (IR) spectra offer lines from new elements, lines of different strengths, and lines at higher excitation potentials compared to the optical. Integrated abundances of C, N, and O are derived from CO, CN, and OH molecular features, while Fe, Na, Mg, Al, Si, K, Ca, and Ti abundances are derived from atomic features. These abundances are compared to previous results from the optical, demonstrating the validity and value of IR IL analyses. The CNO abundances are consistent with typical tip of the red giant branch stellar abundances but are systematically offset from optical Lick index abundances. With a few exceptions, the other abundances agree between the optical and the IR within the 1 σ uncertainties. The first integrated K abundances are also presented and demonstrate that K tracks the α elements. The combination of IR and optical abundances allows better determinations of GC properties and enables probes of the multiple populations in extragalactic GCs. In particular, the integrated effects of the Na/O anticorrelation can be directly examined for the first time.

  20. High-Resolution Mapping of Urban Surface Water Using ZY-3 Multi-Spectral Imagery

    Directory of Open Access Journals (Sweden)

    Fangfang Yao

    2015-09-01

    Full Text Available Accurate information of urban surface water is important for assessing the role it plays in urban ecosystem services under the content of urbanization and climate change. However, high-resolution monitoring of urban water bodies using remote sensing remains a challenge because of the limitation of previous water indices and the dark building shadow effect. To address this problem, we proposed an automated urban water extraction method (UWEM which combines a new water index, together with a building shadow detection method. Firstly, we trained the parameters of UWEM using ZY-3 imagery of Qingdao, China. Then we verified the algorithm using five other sub-scenes (Aksu, Fuzhou, Hanyang, Huangpo and Huainan ZY-3 imagery. The performance was compared with that of the Normalized Difference Water Index (NDWI. Results indicated that UWEM performed significantly better at the sub-scenes with kappa coefficients improved by 7.87%, 32.35%, 12.64%, 29.72%, 14.29%, respectively, and total omission and commission error reduced by 61.53%, 65.74%, 83.51%, 82.44%, and 74.40%, respectively. Furthermore, UWEM has more stable performances than NDWI’s in a range of thresholds near zero. It reduces the over- and under-estimation issues which often accompany previous water indices when mapping urban surface water under complex environmental conditions.

  1. VLT FORS2 comparative transmission spectral survey of clear and cloudy exoplanet atmospheres

    Science.gov (United States)

    Nikolov, Nikolay; Sing, David; Gibson, Neale; Evans, Thomas; Barstow, Joanna Katy; Kataria, Tiffany; Wilson, Paul A.

    2016-10-01

    Transmission spectroscopy is a key to unlocking the secrets of close-in exoplanet atmospheres. Observations have started to unveil a vast diversity of irradiated giant planet atmospheres with clouds and hazes playing a definitive role across the entire mass and temperature regime. We have initiated a ground-based, multi-object transmission spectroscopy of a hand full of hot Jupiters, covering the wavelength range 360-850nm using the recently upgraded FOcal Reducer and Spectrograph (FORS2) mounted on the Very Large Telescope (VLT) at the European Southern Observatory (ESO). These targets were selected for comparative follow-up as their transmission spectra showed evidence for alkali metal absorption, based on the results of Hubble Space Telescope (HST) observations. This talk will discuss the first results from the programme, demonstrating excellent agreement between the transmission spectra measured from VLT and HST and further reinforce the findings of clear, cloudy and hazy atmospheres. More details will be discussed on the narrow alkali features obtained with FORS2 at higher resolution, revealing its high potential in securing optical transmission spectra. These FORS2 observations are the first ground-based detections of clear, cloudy and hazy hot-Jupiter atmosphere with a simultaneous detections of Na, K, and H2 Rayleigh scattering. Our program demonstrates the large potential of the instrument for optical transmission spectroscopy, capable of obtaining HST-quality light curves from the ground. Compared to HST, the larger aperture of VLT will allow for fainter targets to be observed and higher spectral resolution, which can greatly aid comparative exoplanet studies. This is important for further exploring the diversity of exoplanet atmospheres and is particularly complementary to the near- and mid-IR regime, to be covered by the upcoming James-Webb Space Telescope (JWST) and is readily applicable to less massive planets down to super-Earths.

  2. SPECTRAL CLASSIFICATION AND PROPERTIES OF THE O Vz STARS IN THE GALACTIC O-STAR SPECTROSCOPIC SURVEY (GOSSS)

    Energy Technology Data Exchange (ETDEWEB)

    Arias, Julia I.; Barbá, Rodolfo H.; Sabín-Sanjulián, Carolina [Departamento de Física y Astronomía, Universidad de La Serena, Av. Cisternas 1200 Norte, La Serena (Chile); Walborn, Nolan R. [Space Telescope Science Institute, 3700 San Martin Drive, MD 21218, Baltimore (United States); Díaz, Sergio Simón [Instituto de Astrofísica de Canarias, E-38200, Departamento de Astrofísica, Universidad de La Laguna, E-38205, La Laguna, Tenerife (Spain); Apellániz, Jesús Maíz [Centro de Astrobiología, CSIC-INTA, campus ESAC, Camino Bajo del Castillo s/n, E-28 692 Madrid (Spain); Gamen, Roberto C. [Instituto de Astrofísica de La Plata (CONICET, UNLP), Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata (Argentina); Morrell, Nidia I. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Sota, Alfredo [Instituto de Astrofísica de Andalucía-CSIC, Glorieta de la Astronomía s/n, E-18 008 Granada (Spain); Marco, Amparo; Negueruela, Ignacio, E-mail: jarias@userena.cl [Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Escuela Politécnica Superior, Universidad de Alicante, Carretera San Vicente del Raspeig s/n, E03690, San Vicente del Raspeig (Spain); and others

    2016-08-01

    On the basis of the Galactic O Star Spectroscopic Survey (GOSSS), we present a detailed systematic investigation of the O Vz stars. The currently used spectral classification criteria are rediscussed, and the Vz phenomenon is recalibrated through the addition of a quantitative criterion based on the equivalent widths of the He i λ 4471, He ii λ 4542, and He ii λ 4686 spectral lines. The GOSSS O Vz and O V populations resulting from the newly adopted spectral classification criteria are comparatively analyzed. The locations of the O Vz stars are probed, showing a concentration of the most extreme cases toward the youngest star-forming regions. The occurrence of the Vz spectral peculiarity in a solar-metallicity environment, as predicted by the fastwind code, is also investigated, confirming the importance of taking into account several processes for the correct interpretation of the phenomenon.

  3. SPECTRAL CLASSIFICATION AND PROPERTIES OF THE O Vz STARS IN THE GALACTIC O-STAR SPECTROSCOPIC SURVEY (GOSSS)

    International Nuclear Information System (INIS)

    Arias, Julia I.; Barbá, Rodolfo H.; Sabín-Sanjulián, Carolina; Walborn, Nolan R.; Díaz, Sergio Simón; Apellániz, Jesús Maíz; Gamen, Roberto C.; Morrell, Nidia I.; Sota, Alfredo; Marco, Amparo; Negueruela, Ignacio

    2016-01-01

    On the basis of the Galactic O Star Spectroscopic Survey (GOSSS), we present a detailed systematic investigation of the O Vz stars. The currently used spectral classification criteria are rediscussed, and the Vz phenomenon is recalibrated through the addition of a quantitative criterion based on the equivalent widths of the He i λ 4471, He ii λ 4542, and He ii λ 4686 spectral lines. The GOSSS O Vz and O V populations resulting from the newly adopted spectral classification criteria are comparatively analyzed. The locations of the O Vz stars are probed, showing a concentration of the most extreme cases toward the youngest star-forming regions. The occurrence of the Vz spectral peculiarity in a solar-metallicity environment, as predicted by the fastwind code, is also investigated, confirming the importance of taking into account several processes for the correct interpretation of the phenomenon.

  4. Discovery of Water at High Spectral Resolution in the Atmosphere of 51 Peg b

    Science.gov (United States)

    Birkby, J. L.; de Kok, R. J.; Brogi, M.; Schwarz, H.; Snellen, I. A. G.

    2017-03-01

    We report the detection of water absorption features in the day side spectrum of the first-known hot Jupiter, 51 Peg b, confirming the star-planet system to be a double-lined spectroscopic binary. We use high-resolution (R≈ 100,000), 3.2 μ {{m}} spectra taken with CRIRES/VLT to trace the radial-velocity shift of the water features in the planet’s day side atmosphere during 4 hr of its 4.23 day orbit after superior conjunction. We detect the signature of molecular absorption by water at a significance of 5.6σ at a systemic velocity of {V}{sys}=-33+/- 2 km s-1, coincident with the 51 Peg host star, with a corresponding orbital velocity {K}{{P}}={133}-3.5+4.3 km s-1. This translates directly to a planet mass of {M}{{p}}={0.476}-0.031+0.032 {M}{{J}}, placing it at the transition boundary between Jovian and Neptunian worlds. We determine upper and lower limits on the orbital inclination of the system of 70^\\circ bearing molecules of the planet, including methane and carbon dioxide. The atmosphere is non-inverted in the temperature-pressure region probed by these observations. The deepest absorption lines reach an observed relative contrast of 0.9× {10}-3 with respect to the host star continuum flux at an angular separation of 3 milliarcseconds. This work is consistent with a previous tentative report of K-band molecular absorption for 51 Peg b by Brogi et al.

  5. THE HERSCHEL ORION PROTOSTAR SURVEY: SPECTRAL ENERGY DISTRIBUTIONS AND FITS USING A GRID OF PROTOSTELLAR MODELS

    Energy Technology Data Exchange (ETDEWEB)

    Furlan, E. [Infrared Processing and Analysis Center, California Institute of Technology, 770 S. Wilson Ave., Pasadena, CA 91125 (United States); Fischer, W. J. [Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Ali, B. [Space Science Institute, 4750 Walnut Street, Boulder, CO 80301 (United States); Stutz, A. M. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Stanke, T. [ESO, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany); Tobin, J. J. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Megeath, S. T.; Booker, J. [Ritter Astrophysical Research Center, Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606 (United States); Osorio, M. [Instituto de Astrofísica de Andalucía, CSIC, Camino Bajo de Huétor 50, E-18008 Granada (Spain); Hartmann, L.; Calvet, N. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Poteet, C. A. [New York Center for Astrobiology, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Manoj, P. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India); Watson, D. M. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Allen, L., E-mail: furlan@ipac.caltech.edu [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)

    2016-05-01

    We present key results from the Herschel Orion Protostar Survey: spectral energy distributions (SEDs) and model fits of 330 young stellar objects, predominantly protostars, in the Orion molecular clouds. This is the largest sample of protostars studied in a single, nearby star formation complex. With near-infrared photometry from 2MASS, mid- and far-infrared data from Spitzer and Herschel , and submillimeter photometry from APEX, our SEDs cover 1.2–870 μ m and sample the peak of the protostellar envelope emission at ∼100 μ m. Using mid-IR spectral indices and bolometric temperatures, we classify our sample into 92 Class 0 protostars, 125 Class I protostars, 102 flat-spectrum sources, and 11 Class II pre-main-sequence stars. We implement a simple protostellar model (including a disk in an infalling envelope with outflow cavities) to generate a grid of 30,400 model SEDs and use it to determine the best-fit model parameters for each protostar. We argue that far-IR data are essential for accurate constraints on protostellar envelope properties. We find that most protostars, and in particular the flat-spectrum sources, are well fit. The median envelope density and median inclination angle decrease from Class 0 to Class I to flat-spectrum protostars, despite the broad range in best-fit parameters in each of the three categories. We also discuss degeneracies in our model parameters. Our results confirm that the different protostellar classes generally correspond to an evolutionary sequence with a decreasing envelope infall rate, but the inclination angle also plays a role in the appearance, and thus interpretation, of the SEDs.

  6. SPECTRAL LINE SURVEY TOWARD MOLECULAR CLOUDS IN THE LARGE MAGELLANIC CLOUD

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Yuri; Watanabe, Yoshimasa; Yamamoto, Satoshi [Department of Physics, the University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan); Shimonishi, Takashi [Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aramakiazaaoba 6-3, Aoba-ku, Sendai, Miyagi, 980-8578 (Japan); Sakai, Nami [RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aikawa, Yuri [Center for Computational Sciences, The University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Kawamura, Akiko [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo, 181-8588 (Japan)

    2016-02-20

    Spectral line survey observations of seven molecular clouds in the Large Magellanic Cloud (LMC) have been conducted in the 3 mm band with the Mopra 22 m telescope to reveal chemical compositions in low metallicity conditions. Spectral lines of fundamental species such as CS, SO, CCH, HCN, HCO{sup +}, and HNC are detected in addition to those of CO and {sup 13}CO, while CH{sub 3}OH is not detected in any source and N{sub 2}H{sup +} is marginally detected in two sources. The molecular-cloud scale (10 pc scale) chemical composition is found to be similar among the seven sources regardless of different star formation activities, and hence, it represents the chemical composition characteristic of the LMC without influences by star formation activities. In comparison with chemical compositions of Galactic sources, the characteristic features are (1) deficient N-bearing molecules, (2) abundant CCH, and (3) deficient CH{sub 3}OH. Feature (1) is due to a lower elemental abundance of nitrogen in the LMC, whereas features (2) and (3) seem to originate from extended photodissociation regions and warmer temperature in cloud peripheries due to a lower abundance of dust grains in the low metallicity condition. In spite of general resemblance of chemical abundances among the seven sources, the CS/HCO{sup +} and SO/HCO{sup +} ratios are found to be slightly higher in a quiescent molecular cloud. An origin of this trend is discussed in relation to possible depletion of sulfur along the molecular cloud formation.

  7. Detection of wine grape nutrient levels using visible and near infrared 1nm spectral resolution remote sensing

    Science.gov (United States)

    Anderson, Grant; van Aardt, Jan; Bajorski, Peter; Vanden Heuvel, Justine

    2016-05-01

    The grape industry relies on regular crop assessment to aid in the day-to-day and seasonal management of their crop. More specifically, there are six key nutrients of interest to viticulturists in the growing of wine grapes, namely nitrogen, potassium, phosphorous, magnesium, zinc and boron. Traditional methods of determining the levels of these nutrients are through collection and chemical analysis of petiole samples from the grape vines themselves. We collected ground-level observations of the spectra of the grape vines, using a hyperspectral spectrometer (0.4-2.5um), at the same time that petioles samples were harvested. We then interpolated the data into a consistent 1 nm spectral resolution before comparing it to the nutrient data collected. This nutrient data came from both the industry standard petiole analysis, as well as an additional leaf-level analysis. The data were collected for two different grape cultivars, both during bloom and veraison periods to provide variability, while also considering the impact of temporal/seasonal change. A narrow-band NDI (Normalized Difference Index) approach, as well as a simple ratio index, was used to determine the correlation of the reflectance data to the nutrient data. This analysis was limited to the silicon photodiode range to increase the utility of our approach for wavelength-specific cameras (via spectral filters) in a low cost drone platform. The NDI generated correlation coefficients were as high as 0.80 and 0.88 for bloom and veraison, respectively. The ratio index produced correlation coefficient results that are the same at two decimal places with 0.80 and 0.88. These results bode well for eventual non-destructive, accurate and precise assessment of vineyard nutrient status.

  8. High Spectral Resolution SOFIA/EXES Observations of C2H2 toward Orion IRc2

    Science.gov (United States)

    Rangwala, Naseem; Colgan, Sean W. J.; Le Gal, Romane; Acharyya, Kinsuk; Huang, Xinchuan; Lee, Timothy J.; Herbst, Eric; deWitt, Curtis; Richter, Matt; Boogert, Adwin; McKelvey, Mark

    2018-03-01

    We present high spectral resolution observations from 12.96 to 13.33 microns toward Orion IRc2 using the mid-infrared spectrograph, Echelon-Cross-Echelle Spectrograph (EXES), at Stratospheric Observatory for Infrared Astronomy (SOFIA). These observations probe the physical and chemical conditions of the Orion hot core, which is sampled by a bright, compact, mid-infrared background continuum source in the region, IRc2. All 10 of the rovibrational C2H2 transitions expected in our spectral coverage are detected with high signal-to-noise ratios (S/Ns), yielding continuous coverage of the R-branch lines from J = 9–8 to J = 18–17, including both ortho and para species. Eight of these rovibrational transitions are newly reported detections. The isotopologue, 13CCH2, is clearly detected with a high S/N. This enabled a direct measurement of the 12C/13C isotopic ratio for the Orion hot core of 14 ± 1 and an estimated maximum value of 21. We also detected several HCN rovibrational lines. The ortho and para C2H2 ladders are clearly separate, and tracing two different temperatures, 226 K and 164 K, respectively, with a non-equilibrium ortho to para ratio (OPR) of 1.7 ± 0.1. Additionally, the ortho and para V LSR values differ by about 1.8 ± 0.2 km s‑1, while the mean line widths differ by 0.7 ± 0.2 km s‑1, suggesting that these species are not uniformly mixed along the line of sight to IRc2. We propose that the abnormally low C2H2 OPR could be a remnant from an earlier, colder phase, before the density enhancement (now the hot core) was impacted by shocks generated from an explosive event 500 years ago.

  9. High Spectral Resolution Infrared and Raman Lidar Observations for the ARM Program: Clear and Cloudy Sky Applications

    Energy Technology Data Exchange (ETDEWEB)

    Revercomb, Henry; Tobin, David; Knuteson, Robert; Borg, Lori; Moy, Leslie

    2009-06-17

    This grant began with the development of the Atmospheric Emitted Radiance Interferometer (AERI) for ARM. The AERI has provided highly accurate and reliable observations of downwelling spectral radiance (Knuteson et al. 2004a, 2004b) for application to radiative transfer, remote sensing of boundary layer temperature and water vapor, and cloud characterization. One of the major contributions of the ARM program has been its success in improving radiation calculation capabilities for models and remote sensing that evolved from the multi-year, clear-sky spectral radiance comparisons between AERI radiances and line-by-line calculations (Turner et al. 2004). This effort also spurred us to play a central role in improving the accuracy of water vapor measurements, again helping ARM lead the way in the community (Turner et al. 2003a, Revercomb et al. 2003). In order to add high-altitude downlooking AERI-like observations over the ARM sites, we began the development of an airborne AERI instrument that has become known as the Scanning High-resolution Interferometer Sounder (Scanning-HIS). This instrument has become an integral part of the ARM Unmanned Aerospace Vehicle (ARM-UAV) program. It provides both a cross-track mapping view of the earth and an uplooking view from the 12-15 km altitude of the Scaled Composites Proteus aircraft when flown over the ARM sites for IOPs. It has successfully participated in the first two legs of the “grand tour” of the ARM sites (SGP and NSA), resulting in a very good comparison with AIRS observations in 2002 and in an especially interesting data set from the arctic during the Mixed-Phase Cloud Experiment (M-PACE) in 2004.

  10. VizieR Online Data Catalog: Colour and spectral index from the SLUGGS survey (Usher+, 2015)

    Science.gov (United States)

    Usher, C.; Forbes, D. A.; Brodie, J. P.; Romanowsky, A. J.; Strader, J.; Conroy, C.; Foster, C.; Pastorello, N.; Pota, V.; Arnold, J. A.

    2017-10-01

    The SLUGGS survey is an ongoing study of 25 massive, nearby, early-type galaxies and their GC systems using Keck DEIMOS spectroscopy and wide-field imaging from Suprime-Cam (Miyazaki et al. 2002, PASJ, 54, 833) on the Subaru telescope. The spectra were all observed with DEIMOS in multislit mode between 2006 and 2013 with the primary aim of measuring GC radial velocities. Exposure times averaged two hours per slit mask. All observations used a central wavelength of 7800 Å, the 1200 line/mm grating and 1 arcsec slits. This setup yields a resolution of Δλ~1.5 Å and covers the Na I doublet to CaT wavelength region. In roughly half of the slits, Hα is also covered. (3 data files).

  11. Hungaria asteroid region telescopic spectral survey (HARTSS) I: Stony asteroids abundant in the Hungaria background population

    Science.gov (United States)

    Lucas, Michael P.; Emery, Joshua P.; Pinilla-Alonso, Noemi; Lindsay, Sean S.; Lorenzi, Vania

    2017-07-01

    The Hungaria asteroids remain as survivors of late giant planet migration that destabilized a now extinct inner portion of the primordial asteroid belt and left in its wake the current resonance structure of the Main Belt. In this scenario, the Hungaria region represents a ;purgatory; for the closest, preserved samples of the asteroidal material from which the terrestrial planets accreted. Deciphering the surface composition of these unique samples may provide constraints on the nature of the primordial building blocks of the terrestrial planets. We have undertaken an observational campaign entitled the Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) to record near-infrared (NIR) reflectance spectra in order to characterize their taxonomy, surface mineralogy, and potential meteorite analogs. The overall objective of HARTSS is to evaluate the compositional diversity of asteroids located throughout the Hungaria region. This region harbors a collisional family of Xe-type asteroids, which are situated among a background (i.e., non-family) of predominantly S-complex asteroids. In order to assess the compositional diversity of the Hungaria region, we have targeted background objects during Phase I of HARTSS. Collisional family members likely reflect the composition of one original homogeneous parent body, so we have largely avoided them in this phase. We have employed NIR instruments at two ground-based telescope facilities: the NASA Infrared Telescope Facility (IRTF), and the Telescopio Nazionale Galileo (TNG). Our data set includes the NIR spectra of 42 Hungaria asteroids (36 background; 6 family). We find that stony S-complex asteroids dominate the Hungaria background population (29/36 objects; ∼80%). C-complex asteroids are uncommon (2/42; ∼5%) within the Hungaria region. Background S-complex objects exhibit considerable spectral diversity as band parameter measurements of diagnostic absorption features near 1- and 2-μm indicate that several

  12. ASPECT: A spectra clustering tool for exploration of large spectral surveys

    Science.gov (United States)

    in der Au, A.; Meusinger, H.; Schalldach, P. F.; Newholm, M.

    2012-11-01

    Context. Analysing the empirical output from large surveys is an important challenge in contemporary science. Difficulties arise, in particular, when the database is huge and the properties of the object types to be selected are poorly constrained a priori. Aims: We present the novel, semi-automated clustering tool ASPECT for analysing voluminous archives of spectra. Methods: The heart of the program is a neural network in the form of a Kohonen self-organizing map. The resulting map is designed as an icon map suitable for the inspection by eye. The visual analysis is supported by the option to blend in individual object properties such as redshift, apparent magnitude, or signal-to-noise ratio. In addition, the package provides several tools for the selection of special spectral types, e.g. local difference maps which reflect the deviations of all spectra from one given input spectrum (real or artificial). Results: ASPECT is able to produce a two-dimensional topological map of a huge number of spectra. The software package enables the user to browse and navigate through a huge data pool and helps them to gain an insight into underlying relationships between the spectra and other physical properties and to get the big picture of the entire data set. We demonstrate the capability of ASPECT by clustering the entire data pool of ~6 × 105 spectra from the Data Release 4 of the Sloan Digital Sky Survey (SDSS). To illustrate the results regarding quality and completeness we track objects from existing catalogues of quasars and carbon stars, respectively, and connect the SDSS spectra with morphological information from the GalaxyZoo project. Code is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/547/A115

  13. CO (3 – 2) HIGH-RESOLUTION SURVEY OF THE GALACTIC PLANE: R1

    Energy Technology Data Exchange (ETDEWEB)

    Dempsey, J. T.; Thomas, H. S.; Currie, M. J., E-mail: j.dempsey@jach.hawaii.edu, E-mail: h.thomas@jach.hawaii.edu, E-mail: m.currie@jach.hawaii.edu [Joint Astronomy Centre, 660 N. Aohoku Place, Hilo, HI 96720 (United States)

    2013-11-01

    We present the first release (R1) of data from the CO High-Resolution Survey (COHRS), which maps a strip of the inner Galactic plane in {sup 12}CO (J = 3 → 2). The data are taken using the Heterodyne Array Receiver Programme on the James Clerk Maxwell Telescope (JCMT) in Hawaii, which has a 14 arcsec angular resolution at this frequency. When complete, this survey will cover |b| ≤ 0.°5 between 10° < l < 65°. This first release covers |b| ≤ 0.°5 between 10.°25 < l < 17.°5 and 50.°25 < l < 55.°25, and |b| ≤ 0.°25 between 17.°5 < l < 50.°25. The data are smoothed to a velocity resolution of 1 km s{sup –1}, a spatial resolution of 16 arcsec and achieve a mean rms of ∼1 K. COHRS data are available to the community online at http://dx.doi.org/10.11570/13.0002. In this paper we describe the data acquisition and reduction techniques used and present integrated intensity images and longitude-velocity maps. We also discuss the noise characteristics of the data. The high resolution is a powerful tool for morphological studies of bubbles and filaments while the velocity information shows the spiral arms and outflows. These data are intended to complement both existing and upcoming surveys, e.g., the Bolocam Galactic Plane Survey (BGPS), ATLASGAL, the Herschel Galactic Plane Survey (Hi-GAL) and the JCMT Galactic Plane Survey with SCUBA-2 (JPS)

  14. Advances in simultaneous atmospheric profile and cloud parameter regression based retrieval from high-spectral resolution radiance measurements

    Science.gov (United States)

    Weisz, Elisabeth; Smith, William L.; Smith, Nadia

    2013-06-01

    The dual-regression (DR) method retrieves information about the Earth surface and vertical atmospheric conditions from measurements made by any high-spectral resolution infrared sounder in space. The retrieved information includes temperature and atmospheric gases (such as water vapor, ozone, and carbon species) as well as surface and cloud top parameters. The algorithm was designed to produce a high-quality product with low latency and has been demonstrated to yield accurate results in real-time environments. The speed of the retrieval is achieved through linear regression, while accuracy is achieved through a series of classification schemes and decision-making steps. These steps are necessary to account for the nonlinearity of hyperspectral retrievals. In this work, we detail the key steps that have been developed in the DR method to advance accuracy in the retrieval of nonlinear parameters, specifically cloud top pressure. The steps and their impact on retrieval results are discussed in-depth and illustrated through relevant case studies. In addition to discussing and demonstrating advances made in addressing nonlinearity in a linear geophysical retrieval method, advances toward multi-instrument geophysical analysis by applying the DR to three different operational sounders in polar orbit are also noted. For any area on the globe, the DR method achieves consistent accuracy and precision, making it potentially very valuable to both the meteorological and environmental user communities.

  15. The US Geological Survey, digital spectral reflectance library: version 1: 0.2 to 3.0 microns

    Science.gov (United States)

    Clark, Roger N.; Swayze, Gregg A.; King, Trude V. V.; Gallagher, Andrea J.; Calvin, Wendy M.

    1993-01-01

    We have developed a digital reflectance spectral library, with management and spectral analysis software. The library includes 500 spectra of 447 samples (some samples include a series of grain sizes) measured from approximately 0.2 to 3.0 microns. The spectral resolution (Full Width Half Maximum) of the reflectance data is less than or equal to 4 nm in the visible (0.2-0.8 microns) and less than or equal 10 nm in the NIR (0.8-2.35 microns). All spectra were corrected to absolute reflectance using an NBS Halon standard. Library management software lets users search on parameters (e.g. chemical formulae, chemical analyses, purity of samples, mineral groups, etc.) as well as spectral features. Minerals from sulfide, oxide, hydroxide, halide, carbonate, nitrate, borate, phosphate, and silicate groups are represented. X-ray and chemical analyses are tabulated for many of the entries, and all samples have been evaluated for spectral purity. The library also contains end and intermediate members for the olivine, garnet, scapolite, montmorillonite, muscovite, jarosite, and alunite solid-solution series. We have included representative spectra of H2O ice, kerogen, ammonium-bearing minerals, rare-earth oxides, desert varnish coatings, kaolinite crystallinity series, kaolinite-smectite series, zeolite series, and an extensive evaporite series. Because of the importance of vegetation to climate-change studies we have include 17 spectra of tree leaves, bushes, and grasses.

  16. A survey of Bureau of Land Management employees on collaboration and alternative dispute resolution

    Science.gov (United States)

    Ruell, Emily W.; Burkardt, Nina; Donovan, Ryan M.

    2015-01-01

    The Bureau of Land Management (BLM) has been actively expanding its capacity to work cooperatively with other agencies, Tribes, the public, and other stakeholders using collaborative and alternative dispute resolution (ADR) approaches. In 1997, the BLM created the BLM’s Collaboration and Alternative Dispute Resolution Program (Collaboration/ADR Program) to centralize, strengthen, and coordinate these efforts. Specifically, the Collaboration/ADR Program is charged with developing ADR policies; ensuring that statutory and regulatory requirements are met; and providing training, resources, and direct support for collaboration and ADR in the BLM. At the request of the Collaboration/ADR Program, the Policy Analysis and Science Assistance Branch of the U.S. Geological Survey, located in the Fort Collins Science Center, conducted an online survey of BLM employees in early 2013 to address four overarching questions: What information sources and assistance resources are BLM employees currently accessing to fill their conflict/dispute resolution and collaboration needs? 

  17. The High Time Resolution Universe surveys for pulsars and fast transients

    Science.gov (United States)

    Keith, Michael J.

    2013-03-01

    The High Time Resolution Universe survey for pulsars and transients is the first truly all-sky pulsar survey, taking place at the Parkes Radio Telescope in Australia and the Effelsberg Radio Telescope in Germany. Utilising multibeam receivers with custom built all-digital recorders the survey targets the fastest millisecond pulsars and radio transients on timescales of 64 μs to a few seconds. The new multibeam digital filter-bank system at has a factor of eight improvement in frequency resolution over previous Parkes multibeam surveys, allowing us to probe further into the Galactic plane for short duration signals. The survey is split into low, mid and high Galactic latitude regions. The mid-latitude portion of the southern hemisphere survey is now completed, discovering 107 previously unknown pulsars, including 26 millisecond pulsars. To date, the total number of discoveries in the combined survey is 135 and 29 MSPs These discoveries include the first magnetar to be discovered by it's radio emission, unusual low-mass binaries, gamma-ray pulsars and pulsars suitable for pulsar timing array experiments.

  18. Using a spatial and tabular database to generate statistics from terrain and spectral data for soil surveys

    Science.gov (United States)

    Horvath , E.A.; Fosnight, E.A.; Klingebiel, A.A.; Moore, D.G.; Stone, J.E.; Reybold, W.U.; Petersen, G.W.

    1987-01-01

    A methodology has been developed to create a spatial database by referencing digital elevation, Landsat multispectral scanner data, and digitized soil premap delineations of a number of adjacent 7.5-min quadrangle areas to a 30-m Universal Transverse Mercator projection. Slope and aspect transformations are calculated from elevation data and grouped according to field office specifications. An unsupervised classification is performed on a brightness and greenness transformation of the spectral data. The resulting spectral, slope, and aspect maps of each of the 7.5-min quadrangle areas are then plotted and submitted to the field office to be incorporated into the soil premapping stages of a soil survey. A tabular database is created from spatial data by generating descriptive statistics for each data layer within each soil premap delineation. The tabular data base is then entered into a data base management system to be accessed by the field office personnel during the soil survey and to be used for subsequent resource management decisions.Large amounts of data are collected and archived during resource inventories for public land management. Often these data are stored as stacks of maps or folders in a file system in someone's office, with the maps in a variety of formats, scales, and with various standards of accuracy depending on their purpose. This system of information storage and retrieval is cumbersome at best when several categories of information are needed simultaneously for analysis or as input to resource management models. Computers now provide the resource scientist with the opportunity to design increasingly complex models that require even more categories of resource-related information, thus compounding the problem.Recently there has been much emphasis on the use of geographic information systems (GIS) as an alternative method for map data archives and as a resource management tool. Considerable effort has been devoted to the generation of tabular

  19. Survey for C-Band High Spectral Lines with the Arecibo Telescope

    Science.gov (United States)

    Tan, Wei Siang

    High-mass stars have masses greater than 8 solar masses and are the main source of heavy elements such as iron in the interstellar medium. This type of stars form in giant molecular clouds. Studying the molecular environment in star-forming regions is crucial to understand the physical structure and conditions that lead to the formation of high-mass stars. This thesis presents observations conducted with the 305m Arecibo Telescope in Puerto Rico of twelve high-mass star forming regions. Every source was observed in multiple transitions of molecular species including CH, CH3OH, H2CS, and OH lines, and a radio recombination line. The observations were conducted with the C-Band High receiver of the Arecibo Telescope in the frequency range of 6.0 to 7.4GHz. The goals of the observations were to investigate the detectability of different molecular species (including new possible molecular masers) and obtain high sensitivity observations of the 6.7GHz CH3OH line to detect absorption and use it as a probe of the kinematics of the molecular material with respect to the ionized gas. Among the results of the observations, we report detection of 6.7GHz CH3OH masers toward nine regions, OH masers toward five sources, 6.7GHz CH3OH absorption toward four sources (including tentative detections), and detection of H2CS toward the star forming region G34.26+0.15. We also found a variable and recurrent 6.7GHz CH3OH maser in G45.12+0.13. The 6.7GHz CH 3OH and 6278.65MHz H2CS absorption lines were modeled using the radiative transfer code RADEX to investigate the physical conditions of the molecular clouds responsible for the absorption lines. Our analysis of the absorption lines supports the interpretation that the spectral lines are tracing molecular envelopes of HII regions. In the case of 6.7GHz CH 3OH absorption, our results and data from an extensive literature review indicate that absorption is rare, but that a population of 6.7GHz CH 3OH absorbers may be present at levels

  20. Preclinical evaluation and intraoperative human retinal imaging with a high-resolution microscope-integrated spectral domain optical coherence tomography device.

    Science.gov (United States)

    Hahn, Paul; Migacz, Justin; O'Donnell, Rachelle; Day, Shelley; Lee, Annie; Lin, Phoebe; Vann, Robin; Kuo, Anthony; Fekrat, Sharon; Mruthyunjaya, Prithvi; Postel, Eric A; Izatt, Joseph A; Toth, Cynthia A

    2013-01-01

    The authors have recently developed a high-resolution microscope-integrated spectral domain optical coherence tomography (MIOCT) device designed to enable OCT acquisition simultaneous with surgical maneuvers. The purpose of this report is to describe translation of this device from preclinical testing into human intraoperative imaging. Before human imaging, surgical conditions were fully simulated for extensive preclinical MIOCT evaluation in a custom model eye system. Microscope-integrated spectral domain OCT images were then acquired in normal human volunteers and during vitreoretinal surgery in patients who consented to participate in a prospective institutional review board-approved study. Microscope-integrated spectral domain OCT images were obtained before and at pauses in surgical maneuvers and were compared based on predetermined diagnostic criteria to images obtained with a high-resolution spectral domain research handheld OCT system (HHOCT; Bioptigen, Inc) at the same time point. Cohorts of five consecutive patients were imaged. Successful end points were predefined, including ≥80% correlation in identification of pathology between MIOCT and HHOCT in ≥80% of the patients. Microscope-integrated spectral domain OCT was favorably evaluated by study surgeons and scrub nurses, all of whom responded that they would consider participating in human intraoperative imaging trials. The preclinical evaluation identified significant improvements that were made before MIOCT use during human surgery. The MIOCT transition into clinical human research was smooth. Microscope-integrated spectral domain OCT imaging in normal human volunteers demonstrated high resolution comparable to tabletop scanners. In the operating room, after an initial learning curve, surgeons successfully acquired human macular MIOCT images before and after surgical maneuvers. Microscope-integrated spectral domain OCT imaging confirmed preoperative diagnoses, such as full-thickness macular hole

  1. High Spectral Resolution Observation of the Soft Diffuse X-ray Background in the Direction of the Galactic Anti-Center

    Science.gov (United States)

    Wulf, Dallas; Eckart, Mega E.; Galeazzi, Massimiliano; Jaeckel, Felix; Kelley, Richard L.; Kilbourne, Caroline A.; McCammon, Dan; Morgan, Kelsey M.; Porter, Frederick S.; Szymkowiak, Andrew E.

    2018-01-01

    High spectral resolution observations in the soft x-rays are necessary for understanding and modelling the hot component of the interstellar medium and its contribution to the Soft X-ray Background (SXRB). This extended source emission cannot be resolved with most wavelength dispersive spectrometers, making energy dispersive microcalorimeters the ideal choice for these observations. We present here the analysis of the most recent sounding rocket flight of the University of Wisconsin-Madison/Goddard Space Flight Center X-ray Quantum Calorimeter (XQC), a large area silicon thermistor microcalorimeter. This 111 second observation integrates a nearly 1 steradian field of view in the direction of the galactic anti-center (l, b = 165°, -5°) and features ~5 eV spectral resolution below 1 keV. Direct comparison will also be made to the previous, high-latitude observations.

  2. High resolution seismic survey (of the) Rawlins, Wyoming underground coal gasification area. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Youngberg, A.D.; Berkman, E.; Orange, A.S.

    1983-01-01

    In October 1982, a high resolution seismic survey was conducted at the Gulf Research and Development Company's underground coal gasification test site near Rawlins, Wyoming. The objectives of the survey were to utilize high resolution seismic technology to locate and characterize two underground coal burn zones. Seismic data acquisition and processing parameters were specifically designed to emphasize reflections at the shallow depths of interest. A three-dimensional grid of data was obtained over the Rawlins burn zones. Processing included time varying filters, trace composition, and two-dimensional areal stacking of the data in order to identify burn zone anomalies. An anomaly was discernable resulting from the rubble-collapse cavity associated with the burn zone which was studied in detail at the Rawlins 1 and 2 test sites. 21 refs., 20 figs.

  3. Galaxy Evolution Insights from Spectral Modeling of Large Data Sets from the Sloan Digital Sky Survey

    Energy Technology Data Exchange (ETDEWEB)

    Hoversten, Erik A. [Johns Hopkins Univ., Baltimore, MD (United States)

    2007-10-01

    This thesis centers on the use of spectral modeling techniques on data from the Sloan Digital Sky Survey (SDSS) to gain new insights into current questions in galaxy evolution. The SDSS provides a large, uniform, high quality data set which can be exploited in a number of ways. One avenue pursued here is to use the large sample size to measure precisely the mean properties of galaxies of increasingly narrow parameter ranges. The other route taken is to look for rare objects which open up for exploration new areas in galaxy parameter space. The crux of this thesis is revisiting the classical Kennicutt method for inferring the stellar initial mass function (IMF) from the integrated light properties of galaxies. A large data set (~ 105 galaxies) from the SDSS DR4 is combined with more in-depth modeling and quantitative statistical analysis to search for systematic IMF variations as a function of galaxy luminosity. Galaxy Hα equivalent widths are compared to a broadband color index to constrain the IMF. It is found that for the sample as a whole the best fitting IMF power law slope above 0.5 M is Γ = 1.5 ± 0.1 with the error dominated by systematics. Galaxies brighter than around Mr,0.1 = -20 (including galaxies like the Milky Way which has Mr,0.1 ~ -21) are well fit by a universal Γ ~ 1.4 IMF, similar to the classical Salpeter slope, and smooth, exponential star formation histories (SFH). Fainter galaxies prefer steeper IMFs and the quality of the fits reveal that for these galaxies a universal IMF with smooth SFHs is actually a poor assumption. Related projects are also pursued. A targeted photometric search is conducted for strongly lensed Lyman break galaxies (LBG) similar to MS1512-cB58. The evolution of the photometric selection technique is described as are the results of spectroscopic follow-up of the best targets. The serendipitous discovery of two interesting blue compact dwarf galaxies is reported. These

  4. Mutual information registration of multi-spectral and multi-resolution images of DigitalGlobe's WorldView-3 imaging satellite

    Science.gov (United States)

    Miecznik, Grzegorz; Shafer, Jeff; Baugh, William M.; Bader, Brett; Karspeck, Milan; Pacifici, Fabio

    2017-05-01

    WorldView-3 (WV-3) is a DigitalGlobe commercial, high resolution, push-broom imaging satellite with three instruments: visible and near-infrared VNIR consisting of panchromatic (0.3m nadir GSD) plus multi-spectral (1.2m), short-wave infrared SWIR (3.7m), and multi-spectral CAVIS (30m). Nine VNIR bands, which are on one instrument, are nearly perfectly registered to each other, whereas eight SWIR bands, belonging to the second instrument, are misaligned with respect to VNIR and to each other. Geometric calibration and ortho-rectification results in a VNIR/SWIR alignment which is accurate to approximately 0.75 SWIR pixel at 3.7m GSD, whereas inter-SWIR, band to band registration is 0.3 SWIR pixel. Numerous high resolution, spectral applications, such as object classification and material identification, require more accurate registration, which can be achieved by utilizing image processing algorithms, for example Mutual Information (MI). Although MI-based co-registration algorithms are highly accurate, implementation details for automated processing can be challenging. One particular challenge is how to compute bin widths of intensity histograms, which are fundamental building blocks of MI. We solve this problem by making the bin widths proportional to instrument shot noise. Next, we show how to take advantage of multiple VNIR bands, and improve registration sensitivity to image alignment. To meet this goal, we employ Canonical Correlation Analysis, which maximizes VNIR/SWIR correlation through an optimal linear combination of VNIR bands. Finally we explore how to register images corresponding to different spatial resolutions. We show that MI computed at a low-resolution grid is more sensitive to alignment parameters than MI computed at a high-resolution grid. The proposed modifications allow us to improve VNIR/SWIR registration to better than ¼ of a SWIR pixel, as long as terrain elevation is properly accounted for, and clouds and water are masked out.

  5. Disputes over science and dispute resolution approaches - A survey of Bureau of Reclamation employees

    Science.gov (United States)

    Burkardt, Nina; Ruell, Emily W.

    2012-01-01

    Water resources in parts of the Western United States are over-allocated, which intensifies the pressure to support water management decisions with strong scientific evidence. Because scientific studies sometimes provide uncertain or competing results or recommendations, science can become a source of disputes during decision-making processes. The Bureau of Reclamation (Reclamation) is an important water manager in the Western United States, and Reclamation decision processes are often contested by a variety of affected constituencies. We conducted a Web-based survey of Reclamation employees to determine (1) which types of disputes over science are occurring and how common they are, (2) which approaches have been used by Reclamation to try to resolve these different types of disputes, (3) how useful Reclamation employees find these approaches at resolving these types of disputes, (4) the final outcomes of these disputes and the decision-making processes that were hindered by the disputes over science, and (5) the potential usefulness of several different types of dispute resolution resources that Reclamation could provide for employees that become involved in disputes over science. The calculated minimum response rate for the survey was 59 percent. Twenty-five percent of respondents indicated that they had been involved in a dispute over science while working at Reclamation. Native species and species listed under the Endangered Species Act of 1973 were the most common issue types reported in these disputes over science. Survey respondents indicated that they used a variety of approaches to resolve disputes over science and rated most approaches as either neutral or somewhat helpful in these endeavors. Future research is needed to determine whether there are additional variables underlying these disputes that were not measured in this survey that may identify when dispute resolution methods are most effective, or whether resolving aspects of these disputes, such as

  6. Dust spectral energy distributions of nearby galaxies: an insight from the Herschel Reference Survey

    Science.gov (United States)

    Ciesla, L.; Boquien, M.; Boselli, A.; Buat, V.; Cortese, L.; Bendo, G. J.; Heinis, S.; Galametz, M.; Eales, S.; Smith, M. W. L.; Baes, M.; Bianchi, S.; De Looze, I.; di Serego Alighieri, S.; Galliano, F.; Hughes, T. M.; Madden, S. C.; Pierini, D.; Rémy-Ruyer, A.; Spinoglio, L.; Vaccari, M.; Viaene, S.; Vlahakis, C.

    2014-05-01

    Although it accounts only for a small fraction of the baryonic mass, dust has a profound impact on the physical processes at play in galaxies. Thus, to understand the evolution of galaxies, it is essential not only to characterize dust properties per se, but also in relation to global galaxy properties. To do so, we derive the dust properties of galaxies in a volume limited, K-band selected sample, the Herschel Reference Survey (HRS). We gather infrared photometric data from 8 μm to 500 μm from Spitzer, WISE, IRAS, and Herschel for all of the HRS galaxies. Draine & Li (2007, ApJ, 663, 866) models are fit to the data from which the stellar contribution has been carefully removed. We find that our photometric coverage is sufficient to constrain all of the parameters of the Draine & Li models and that a strong constraint on the 20-60 μm range is mandatory to estimate the relative contribution of the photo-dissociation regions to the infrared spectral energy distribution (SED). The SED models tend to systematically underestimate the observed 500 μm flux densities, especially for low-mass systems. We provide the output parameters for all of the galaxies, i.e., the minimum intensity of the interstellar radiation field, the fraction of polycyclic aromatic hydrocarbon (PAH), the relative contribution of PDR and evolved stellar population to the dust heating, the dust mass, and the infrared luminosity. For a subsample of gas-rich galaxies, we analyze the relations between these parameters and the main integrated properties of galaxies, such as stellar mass, star formation rate, infraredluminosity, metallicity, Hα and H-band surface brightness, and the far-ultraviolet attenuation. A good correlation between the fraction of PAH and the metallicity is found, implying a weakening of the PAH emission in galaxies with low metallicities and, thus, low stellar masses. The intensity of the diffuse interstellar radiation field and the H-band and Hα surface brightnesses are

  7. High-resolution topography using SfM-photogrammetry from UAV for coastal mudflat geomorphic surveys

    Science.gov (United States)

    Fleury, Jules; Brunier, Guillaume; Michaud, Emma; Anthony, Edward; Morvan, Sylvain; Dussouillez, Philippe; Gardel, Antoine

    2016-04-01

    The coast between the Amazon and the Orinoco river mouths comprises mud banks formed from the large muddy discharge of the Amazon and migrating westward under the influence of waves and currents. These banks are highly dynamic and strongly affected by complex hydro-bio-geochemical interactions that are also important in mangrove colonization of bare mudflats in the upper intertidal zone of these banks. The surface topography of these mud banks is further affected by physical and biological processes such as tidal channel incision and bioturbation. Surveying the morphology of these mudflats over large areas and at a high-resolution without perturbing their surface is a real challenge that cannot be accomplished using classical survey methods such as RTK-GPS or Total Stations. To overcome this hurdle, we conducted a SfM(Surface from Motion)-photogrammetry experiment over 1 ha of a large intertidal mudflat colonized by pioneer mangroves at the mouth of the Sinnamary estuary in French Guiana. We developed a topographic data acquisition system based on sub-vertical aerial photography from a UAV flying at low altitude (15 m), in order to produce images at 3 mm resolution. A light DJI F550 drone was used, with an automatic flight programming using GPS navigation and a flight plan designed on photogrammetric criteria. The payload was a lightweight (250 grams) Ricoh GR camera with an APS-C sensor of 16.2 Megapixel and including an intervalometer triggering function. The drone had a flight autonomy of 12 minutes thus covering entirely the surrounding mudflat platform. The landing procedure was conducted manually in order for the drone to land safely on a very narrow artificial ground base set up for our experiment. 3D-models and derived products were generated using Agisoft Photoscan Professionnal software. We produced a gridded Digital Surface Model (DSM) and an orthophoto in visible bands at 1 cm and 5mm pixel resolution respectively. The vertical accuracy of the DSM based

  8. High-resolution quantization based on soliton self-frequency shift and spectral compression in a bi-directional comb-fiber architecture

    Science.gov (United States)

    Zhang, Xuyan; Zhang, Zhiyao; Wang, Shubing; Liang, Dong; Li, Heping; Liu, Yong

    2018-03-01

    We propose and demonstrate an approach that can achieve high-resolution quantization by employing soliton self-frequency shift and spectral compression. Our approach is based on a bi-directional comb-fiber architecture which is composed of a Sagnac-loop-based mirror and a comb-like combination of N sections of interleaved single-mode fibers and high nonlinear fibers. The Sagnac-loop-based mirror placed at the terminal of a bus line reflects the optical pulses back to the bus line to achieve additional N-stage spectral compression, thus single-stage soliton self-frequency shift (SSFS) and (2 N - 1)-stage spectral compression are realized in the bi-directional scheme. The fiber length in the architecture is numerically optimized, and the proposed quantization scheme is evaluated by both simulation and experiment in the case of N = 2. In the experiment, a quantization resolution of 6.2 bits is obtained, which is 1.2-bit higher than that of its uni-directional counterpart.

  9. High-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region, California

    Science.gov (United States)

    Ponce, D. A.; Mangan, M.; McPhee, D.

    2013-12-01

    A new high-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region greatly enhances previous magnetic interpretations that were based on older, low-resolution, and regional aeromagnetic data sets and provides new insights into volcano-tectonic processes. The surveyed area covers a 8,750 km2 NNW-trending swath situated between the Sierra Nevada to the west and the Basin and Range Province to the east. The surveyed area includes the volcanic centers of Mono Lake, Mono-Inyo Craters, Mammoth Mountain, Devils Postpile, and Long Valley Caldera. The NW-trending eastern Sierra frontal fault zone crosses through the study area, including the active Mono Lake, Silver Lake, Hartley Springs, Laurel Creek, and Hilton Creek faults. Over 6,000 line-kilometers of aeromagnetic data were collected at a constant terrain clearance of 150 m, a flight-line spacing of 400 m, and a tie-line spacing of 4 km. Data were collected via helicopter with an attached stinger housing a magnetic sensor using a Scintrex CS-3 cesium magnetometer. In the northern part of the survey area, data improve the magnetic resolution of the individual domes and coulees along Mono Craters and a circular shaped magnetic anomaly that coincides with a poorly defined ring fracture mapped by Kistler (1966). Here, aeromagnetic data combined with other geophysical data suggests that Mono Craters may have preferentially followed a pre-existing plutonic basement feature that may have controlled the sickle shape of the volcanic chain. In the northeastern part of the survey, aeromagnetic data reveal a linear magnetic anomaly that correlates with and extends a mapped fault. In the southern part of the survey, in the Sierra Nevada block just south of Long Valley Caldera, aeromagnetic anomalies correlate with NNW-trending Sierran frontal faults rather than to linear NNE-trends observed in recent seismicity over the last 30 years. These data provide an important framework for the further analysis of the

  10. The RINGS Survey. III. Medium-resolution Hα Fabry–Pérot Kinematic Data Set

    Science.gov (United States)

    Mitchell, Carl J.; Sellwood, J. A.; Williams, T. B.; Spekkens, Kristine; Kuzio de Naray, Rachel; Bixel, Alex

    2018-03-01

    The distributions of stars, gas, and dark matter in disk galaxies provide important constraints on galaxy formation models, particularly on small spatial scales (spiral galaxies. For each of these galaxies, we obtain and model Hα and H I 21 cm spectroscopic data as well as multi-band photometric data. We intend to use these models to explore the underlying structure and evolution of these galaxies in a cosmological context, as well as whether the predictions of ΛCDM are consistent with the mass distributions of these galaxies. In this paper, we present spectroscopic imaging data for 14 of the RINGS galaxies observed with the medium spectral resolution Fabry–Pérot etalon on the Southern African Large Telescope. From these observations, we derive high spatial resolution line-of-sight velocity fields of the Hα line of excited hydrogen, as well as maps and azimuthally averaged profiles of the integrated Hα and [N II] emission and oxygen abundances. We then model these kinematic maps with axisymmetric models, from which we extract rotation curves and projection geometries for these galaxies. We show that our derived rotation curves agree well with other determinations, and the similarity of the projection angles with those derived from our photometric images argues against these galaxies having intrinsically oval disks.

  11. AN INTERFEROMETRIC SPECTRAL LINE AND IMAGING SURVEY OF VY CANIS MAJORIS IN THE 345 GHz BAND

    International Nuclear Information System (INIS)

    Kamiński, T.; Menten, K. M.; Gottlieb, C. A.; Young, K. H.; Patel, N. A.

    2013-01-01

    A spectral line survey of the oxygen-rich red supergiant VY Canis Majoris was made between 279 and 355 GHz with the Submillimeter Array (SMA). Two hundred twenty-three spectral features from 19 molecules (not counting isotopic species of some of them) were observed, including the rotational spectra of TiO, TiO 2 , and AlCl for the first time in this source. The parameters and an atlas of all spectral features are presented. Observations of each line with a synthesized beam of ∼0.''9, reveal the complex kinematics and morphology of the nebula surrounding VY CMa. Many of the molecules are observed in high-lying rotational levels or in excited vibrational levels. From these, it was established that the main source of the submillimeter-wave continuum (dust) and the high-excitation molecular gas (the star) are separated by about 0.''15. Apparent coincidences between the molecular gas observed with the SMA, and some of the arcs and knots observed at infrared wavelengths and in the optical scattered light by the Hubble Space Telescope are identified. The observations presented here provide important constraints on the molecular chemistry in oxygen-dominated circumstellar environments and a deeper picture of the complex circumstellar environment of VY CMa

  12. SMA OBSERVATIONS OF CLASS 0 PROTOSTARS: A HIGH ANGULAR RESOLUTION SURVEY OF PROTOSTELLAR BINARY SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xuepeng [Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008 (China); Arce, Hector G.; Dunham, Michael M. [Department of Astronomy, Yale University, Box 208101, New Haven, CT 06520-8101 (United States); Zhang Qizhou; Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Launhardt, Ralf; Henning, Thomas [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Jorgensen, Jes K. [Niels Bohr Institute and Centre for Star and Planet Formation, Copenhagen University, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Lee, Chin-Fei [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China); Foster, Jonathan B. [Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States); Pineda, Jaime E., E-mail: xpchen@pmo.ac.cn, E-mail: xuepeng.chen@yale.edu [ESO, Karl Schwarzschild Str. 2, D-85748 Garching bei Munchen (Germany)

    2013-05-10

    We present high angular resolution 1.3 mm and 850 {mu}m dust continuum data obtained with the Submillimeter Array toward 33 Class 0 protostars in nearby clouds (distance < 500 pc), which represents so far the largest survey toward protostellar binary/multiple systems. The median angular resolution in the survey is 2.''5, while the median linear resolution is approximately 600 AU. Compact dust continuum emission is observed from all sources in the sample. Twenty-one sources in the sample show signatures of binarity/multiplicity, with separations ranging from 50 AU to 5000 AU. The numbers of singles, binaries, triples, and quadruples in the sample are 12, 14, 5, and 2, respectively. The derived multiplicity frequency (MF) and companion star fraction (CSF) for Class 0 protostars are 0.64 {+-} 0.08 and 0.91 {+-} 0.05, respectively, with no correction for completeness. The derived MF and CSF in this survey are approximately two times higher than the values found in the binary surveys toward Class I young stellar objects, and approximately three (for MF) and four (for CSF) times larger than the values found among main-sequence stars, with a similar range of separations. Furthermore, the observed fraction of high-order multiple systems to binary systems in Class 0 protostars (0.50 {+-} 0.09) is also larger than the fractions found in Class I young stellar objects (0.31 {+-} 0.07) and main-sequence stars ({<=}0.2). These results suggest that binary properties evolve as protostars evolve, as predicted by numerical simulations. The distribution of separations for Class 0 protostellar binary/multiple systems shows a general trend in which CSF increases with decreasing companion separation. We find that 67% {+-} 8% of the protobinary systems have circumstellar mass ratios below 0.5, implying that unequal-mass systems are preferred in the process of binary star formation. We suggest an empirical sequential fragmentation picture for binary star formation, based on this

  13. Mapping Impervious Surfaces Globally at 30m Resolution Using Landsat Global Land Survey Data

    Science.gov (United States)

    Brown de Colstoun, E.; Huang, C.; Wolfe, R. E.; Tan, B.; Tilton, J.; Smith, S.; Phillips, J.; Wang, P.; Ling, P.; Zhan, J.; Xu, X.; Taylor, M. P.

    2013-12-01

    Impervious surfaces, mainly artificial structures and roads, cover less than 1% of the world's land surface (1.3% over USA). Regardless of the relatively small coverage, impervious surfaces have a significant impact on the environment. They are the main source of the urban heat island effect, and affect not only the energy balance, but also hydrology and carbon cycling, and both land and aquatic ecosystem services. In the last several decades, the pace of converting natural land surface to impervious surfaces has increased. Quantitatively monitoring the growth of impervious surface expansion and associated urbanization has become a priority topic across both the physical and social sciences. The recent availability of consistent, global scale data sets at 30m resolution such as the Global Land Survey from the Landsat satellites provides an unprecedented opportunity to map global impervious cover and urbanization at this resolution for the first time, with unprecedented detail and accuracy. Moreover, the spatial resolution of Landsat is absolutely essential to accurately resolve urban targets such a buildings, roads and parking lots. With long term GLS data now available for the 1975, 1990, 2000, 2005 and 2010 time periods, the land cover/use changes due to urbanization can now be quantified at this spatial scale as well. In the Global Land Survey - Imperviousness Mapping Project (GLS-IMP), we are producing the first global 30 m spatial resolution impervious cover data set. We have processed the GLS 2010 data set to surface reflectance (8500+ TM and ETM+ scenes) and are using a supervised classification method using a regression tree to produce continental scale impervious cover data sets. A very large set of accurate training samples is the key to the supervised classifications and is being derived through the interpretation of high spatial resolution (~2 m or less) commercial satellite data (Quickbird and Worldview2) available to us through the unclassified

  14. The CARMENES search for exoplanets around M dwarfs. High-resolution optical and near-infrared spectroscopy of 324 survey stars

    Science.gov (United States)

    Reiners, A.; Zechmeister, M.; Caballero, J. A.; Ribas, I.; Morales, J. C.; Jeffers, S. V.; Schöfer, P.; Tal-Or, L.; Quirrenbach, A.; Amado, P. J.; Kaminski, A.; Seifert, W.; Abril, M.; Aceituno, J.; Alonso-Floriano, F. J.; Ammler-von Eiff, M.; Antona, R.; Anglada-Escudé, G.; Anwand-Heerwart, H.; Arroyo-Torres, B.; Azzaro, M.; Baroch, D.; Barrado, D.; Bauer, F. F.; Becerril, S.; Béjar, V. J. S.; Benítez, D.; Berdinas˜, Z. M.; Bergond, G.; Blümcke, M.; Brinkmöller, M.; del Burgo, C.; Cano, J.; Cárdenas Vázquez, M. C.; Casal, E.; Cifuentes, C.; Claret, A.; Colomé, J.; Cortés-Contreras, M.; Czesla, S.; Díez-Alonso, E.; Dreizler, S.; Feiz, C.; Fernández, M.; Ferro, I. M.; Fuhrmeister, B.; Galadí-Enríquez, D.; Garcia-Piquer, A.; García Vargas, M. L.; Gesa, L.; Galera, V. Gómez; González Hernández, J. I.; González-Peinado, R.; Grözinger, U.; Grohnert, S.; Guàrdia, J.; Guenther, E. W.; Guijarro, A.; Guindos, E. de; Gutiérrez-Soto, J.; Hagen, H.-J.; Hatzes, A. P.; Hauschildt, P. H.; Hedrosa, R. P.; Helmling, J.; Henning, Th.; Hermelo, I.; Hernández Arabí, R.; Hernández Castaño, L.; Hernández Hernando, F.; Herrero, E.; Huber, A.; Huke, P.; Johnson, E. N.; Juan, E. de; Kim, M.; Klein, R.; Klüter, J.; Klutsch, A.; Kürster, M.; Lafarga, M.; Lamert, A.; Lampón, M.; Lara, L. M.; Laun, W.; Lemke, U.; Lenzen, R.; Launhardt, R.; López del Fresno, M.; López-González, J.; López-Puertas, M.; López Salas, J. F.; López-Santiago, J.; Luque, R.; Magán Madinabeitia, H.; Mall, U.; Mancini, L.; Mandel, H.; Marfil, E.; Marín Molina, J. A.; Maroto Fernández, D.; Martín, E. L.; Martín-Ruiz, S.; Marvin, C. J.; Mathar, R. J.; Mirabet, E.; Montes, D.; Moreno-Raya, M. E.; Moya, A.; Mundt, R.; Nagel, E.; Naranjo, V.; Nortmann, L.; Nowak, G.; Ofir, A.; Oreiro, R.; Pallé, E.; Panduro, J.; Pascual, J.; Passegger, V. M.; Pavlov, A.; Pedraz, S.; Pérez-Calpena, A.; Medialdea, D. Pérez; Perger, M.; Perryman, M. A. C.; Pluto, M.; Rabaza, O.; Ramón, A.; Rebolo, R.; Redondo, P.; Reffert, S.; Reinhart, S.; Rhode, P.; Rix, H.-W.; Rodler, F.; Rodríguez, E.; Rodríguez-López, C.; Rodríguez Trinidad, A.; Rohloff, R.-R.; Rosich, A.; Sadegi, S.; Sánchez-Blanco, E.; Sánchez Carrasco, M. A.; Sánchez-López, A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schäfer, S.; Schmitt, J. H. M. M.; Schiller, J.; Schweitzer, A.; Solano, E.; Stahl, O.; Strachan, J. B. P.; Stürmer, J.; Suárez, J. C.; Tabernero, H. M.; Tala, M.; Trifonov, T.; Tulloch, S. M.; Ulbrich, R. G.; Veredas, G.; Vico Linares, J. I.; Vilardell, F.; Wagner, K.; Winkler, J.; Wolthoff, V.; Xu, W.; Yan, F.; Zapatero Osorio, M. R.

    2018-04-01

    The CARMENES radial velocity (RV) survey is observing 324 M dwarfs to search for any orbiting planets. In this paper, we present the survey sample by publishing one CARMENES spectrum for each M dwarf. These spectra cover the wavelength range 520-1710 nm at a resolution of at least R >80 000, and we measure its RV, Hα emission, and projected rotation velocity. We present an atlas of high-resolution M-dwarf spectra and compare the spectra to atmospheric models. To quantify the RV precision that can be achieved in low-mass stars over the CARMENES wavelength range, we analyze our empirical information on the RV precision from more than 6500 observations. We compare our high-resolution M-dwarf spectra to atmospheric models where we determine the spectroscopic RV information content, Q, and signal-to-noise ratio. We find that for all M-type dwarfs, the highest RV precision can be reached in the wavelength range 700-900 nm. Observations at longer wavelengths are equally precise only at the very latest spectral types (M8 and M9). We demonstrate that in this spectroscopic range, the large amount of absorption features compensates for the intrinsic faintness of an M7 star. To reach an RV precision of 1 m s-1 in very low mass M dwarfs at longer wavelengths likely requires the use of a 10 m class telescope. For spectral types M6 and earlier, the combination of a red visual and a near-infrared spectrograph is ideal to search for low-mass planets and to distinguish between planets and stellar variability. At a 4 m class telescope, an instrument like CARMENES has the potential to push the RV precision well below the typical jitter level of 3-4 m s-1.

  15. The UV-A and visible solar irradiance spectrum: inter-comparison of absolutely calibrated, spectrally medium resolution solar irradiance spectra from balloon- and satellite-borne measurements

    Directory of Open Access Journals (Sweden)

    W. Gurlit

    2005-01-01

    Full Text Available Within the framework of the ENVISAT/-SCIAMACHY satellite validation, solar irradiance spectra are absolutely measured at moderate resolution in the UV/visible spectral range (in the UV from 316.7-418 nm and the visible from 400-652 nm at a full width half maximum resolution of 0.55 nm and 1.48 nm, respectively from aboard the azimuth-controlled LPMA/DOAS balloon gondola at around 32 km balloon float altitude. After accounting for the atmospheric extinction due to Rayleigh scattering and gaseous absorption (O3 and NO2, the measured solar spectra are compared with previous observations. Our solar irradiance spectrum perfectly agrees within +0.03% with the re-calibrated Kurucz et al. (1984 solar spectrum (Fontenla et al., 1999, called MODTRAN 3.7 in the visible spectral range (415-650 nm, but it is +2.1% larger in the (370-415 nm wavelength interval, and -4% smaller in the UV-A spectral range (316.7-370 nm, when the Kurucz spectrum is convolved to the spectral resolution of our instrument. Similar comparisons of the SOLSPEC (Thuillier et al., 1997, 1998a, b and SORCE/SIM (Harder et al., 2000 solar spectra with MODTRAN 3.7 confirms our findings with the values being -0.5%, +2%, and -1.4% for SOLSPEC -0.33%, -0.47%, and -6.2% for SORCE/SIM, respectively. Comparison of the SCIAMACHY solar spectrum from channels 1 to 4 (- re-calibrated by the University of Bremen - with MODTRAN 3.7 indicates an agreement within -0.4% in the visible spectral range (415-585 nm, -1.6% within the 370-415 nm, and -5.7% within 325-370 nm wavelength interval, in agreement with the results of the other sensors. In agreement with findings of Skupin et al. (2002 our study emphasizes that the present ESA SCIAMACHY level 1 calibration is systematically +15% larger in the considered wavelength intervals when compared to all available other solar irradiance measurements.

  16. ROV seafloor surveys combining 5-cm lateral resolution multibeam bathymetry with color stereo photographic imagery

    Science.gov (United States)

    Caress, D. W.; Hobson, B.; Thomas, H. J.; Henthorn, R.; Martin, E. J.; Bird, L.; Rock, S. M.; Risi, M.; Padial, J. A.

    2013-12-01

    The Monterey Bay Aquarium Research Institute is developing a low altitude, high-resolution seafloor mapping capability that combines multibeam sonar with stereo photographic imagery. The goal is to obtain spatially quantitative, repeatable renderings of the seafloor with fidelity at scales of 5 cm or better from altitudes of 2-3 m. The initial test surveys using this sensor system are being conducted from a remotely operated vehicle (ROV). Ultimately we intend to field this survey system from an autonomous underwater vehicle (AUV). This presentation focuses on the current sensor configuration, methods for data processing, and results from recent test surveys. Bathymetry data are collected using a 400-kHz Reson 7125 multibeam sonar. This configuration produces 512 beams across a 135° wide swath; each beam has a 0.5° acrosstrack by 1.0° alongtrack angular width. At a 2-m altitude, the nadir beams have a 1.7-cm acrosstrack and 3.5 cm alongtrack footprint. Dual Allied Vision Technology GX1920 2.8 Mpixel color cameras provide color stereo photography of the seafloor. The camera housings have been fitted with corrective optics achieving a 90° field of view through a dome port. Illumination is provided by dual 100J xenon strobes. Position, depth, and attitude data are provided by a Kearfott SeaDevil Inertial Navigation System (INS) integrated with a 300 kHz RDI Doppler velocity log (DVL). A separate Paroscientific pressure sensor is mounted adjacent to the INS. The INS Kalman filter is aided by the DVL velocity and pressure data, achieving navigational drift rates less than 0.05% of the distance traveled during surveys. The sensors are mounted onto a toolsled fitted below MBARI's ROV Doc Ricketts with the sonars, cameras and strobes all pointed vertically down. During surveys the ROV flies at a 2-m altitude at speeds of 0.1-0.2 m/s. During a four-day R/V Western Flyer cruise in June 2013, we successfully collected multibeam and camera survey data from a 2-m altitude

  17. In-Situ Assay Of Transuranic Radionuclides In The Vadose Zone Using High-Resolution Spectral Gamma Logging - A Hanford Case Study

    International Nuclear Information System (INIS)

    Rohay, V.J.; Henwood, P.; McCain, R.

    2009-01-01

    High-resolution spectral gamma logging in steel-cased boreholes is used to detect and quantify transuranic radionuclides in the subsurface. Pu-239, Pu-241, Am-241, and Np-237 are identified based on characteristic decay gammas. Typical minimum detectable levels are on the order of 20 to 40 nCi/g. In intervals of high transuranic concentrations, gamma rays from other sources may complicate analysis and interpretation. Gamma rays detected in the borehole may originate from three sources: decay of the parent transuranic radionuclide or a daughter; alpha interactions; and interactions with neutrons resulting from either spontaneous fission or alpha particle interactions.

  18. Herschel Observations of Extraordinary Sources: Analysis of the HIFI 1.2 THz Wide Spectral Survey toward Orion KL. I. Methods

    NARCIS (Netherlands)

    Crockett, Nathan R.; Bergin, Edwin A.; Neill, Justin L.; Favre, Cécile; Schilke, Peter; Lis, Dariusz C.; Bell, Tom A.; Blake, Geoffrey; Cernicharo, José; Emprechtinger, Martin; Esplugues, Gisela B.; Gupta, Harshal; Kleshcheva, Maria; Lord, Steven; Marcelino, Nuria; McGuire, Brett A.; Pearson, John; Phillips, Thomas G.; Plume, Rene; van der Tak, Floris; Tercero, Belén; Yu, Shanshan

    We present a comprehensive analysis of a broadband spectral line survey of the Orion Kleinmann-Low nebula (Orion KL), one of the most chemically rich regions in the Galaxy, using the HIFI instrument on board the Herschel Space Observatory. This survey spans a frequency range from 480 to 1907 GHz at

  19. ARCHAEOLOGICAL SURVEYS ON THE GERMAN NORTH SEA COAST USING HIGH-RESOLUTION SYNTHETIC APERTURE RADAR DATA

    Directory of Open Access Journals (Sweden)

    M. Gade

    2017-11-01

    Full Text Available We show that high-resolution space-borne Synthetic Aperture Radar (SAR imagery with pixel sizes well below 1 m2 can be used to complement archaeological surveys in areas that are difficult to access. After major storm surges in the 14th and 17th centuries, vast areas on the German North Sea coast were lost to the sea. Areas of former settlements and historical land use were buried under sediments for centuries, but when the surface layer is driven away under the permanent action of wind, currents, and waves, they appear again on the Wadden Sea surface. However, the frequent flooding and erosion of the intertidal flats make any archaeological monitoring a difficult task, so that remote sensing techniques appear to be an efficient and cost-effective instrument for any archaeological surveillance of that area. Space-borne SAR images clearly show remnants of farmhouse foundations and of former systems of ditches, dating back to the 14th and to the 16th/17th centuries. In particular, the very high-resolution acquisition (staring spotlight mode of the German TerraSAR/ TanDEM-X satellites allows for the detection of various kinds of residuals of historical land use with high precision. In addition, we also investigate the capability of SARs working at lower microwave frequencies (on Radarsat-2 to complement our archaeological survey of historical cultural traces, some of which have been unknown so far.

  20. Global spectroscopic survey of cloud thermodynamic phase at high spatial resolution, 2005-2015

    Science.gov (United States)

    Thompson, David R.; Kahn, Brian H.; Green, Robert O.; Chien, Steve A.; Middleton, Elizabeth M.; Tran, Daniel Q.

    2018-02-01

    The distribution of ice, liquid, and mixed phase clouds is important for Earth's planetary radiation budget, impacting cloud optical properties, evolution, and solar reflectivity. Most remote orbital thermodynamic phase measurements observe kilometer scales and are insensitive to mixed phases. This under-constrains important processes with outsize radiative forcing impact, such as spatial partitioning in mixed phase clouds. To date, the fine spatial structure of cloud phase has not been measured at global scales. Imaging spectroscopy of reflected solar energy from 1.4 to 1.8 µm can address this gap: it directly measures ice and water absorption, a robust indicator of cloud top thermodynamic phase, with spatial resolution of tens to hundreds of meters. We report the first such global high spatial resolution survey based on data from 2005 to 2015 acquired by the Hyperion imaging spectrometer onboard NASA's Earth Observer 1 (EO-1) spacecraft. Seasonal and latitudinal distributions corroborate observations by the Atmospheric Infrared Sounder (AIRS). For extratropical cloud systems, just 25 % of variance observed at GCM grid scales of 100 km was related to irreducible measurement error, while 75 % was explained by spatial correlations possible at finer resolutions.

  1. Investigation of spectral interferences in the determination of lead in fertilizers and limestone samples using high-resolution continuum source graphite furnace atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Aline R. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Becker, Emilene M.; François, Luciane L.; Jesus, Alexandre de [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Vale, Maria Goreti R. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Welz, Bernhard [Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Dessuy, Morgana B., E-mail: mbdessuy@ufrgs.br [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Andrade, Jailson B. de [Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil)

    2014-11-01

    In the present work, spectral interferences on the determination of lead in fertilizer and limestone samples were investigated using high-resolution continuum source graphite furnace atomic absorption spectrometry at the main analytical lines: 217.001 and 283.306 nm. For these investigations, samples were introduced into the furnace as slurry together with a mixture of Pd and Mg as chemical modifier. Spectral interferences were observed for some samples at both analytical lines. In order to verify whether a wet digestion procedure would avoid these interferences, a reference method for wet digestion of fertilizers was employed as an alternative sample preparation procedure. However, the same interferences were also observed in the digested samples. In order to identify and eliminate the fine-structured background using a least-squares background correction, reference spectra were generated using the combination of different species. The use of the latter technique allowed the elimination of spectral interferences for most of the investigated samples, making possible the determination of lead in fertilizer and limestone samples free of interferences. The best results were found using a reference spectrum of NH{sub 4}H{sub 2}PO{sub 4} at 217.001 nm, and a mixture of H{sub 2}SO{sub 4} + Ca and HNO{sub 3} + Ca at the 283.306 nm line. The accuracy of the method was evaluated using a certified reference material “Trace Elements in Multi-Nutrient Fertilizer”. Similar results were obtained using line source graphite furnace atomic absorption spectrometry with Zeeman-effect background correction, indicating that the latter technique was also capable to correct the spectral interferences, at least in part. - Highlights: • Spectral interferences on the determination of lead in fertilizers and limestone. • The analytical lines at 217.001 nm and 283.306 nm using HR-CS GF AAS. • Various combinations of compounds were used to create reference spectra. • LSBC

  2. Search for extraterrestrial intelligence/high resolution microwave survey team member

    Science.gov (United States)

    Steffes, Paul G.

    1993-01-01

    This semiannual status report describes activities conducted by the Principal Investigator during the first half of this third year of the NASA High Resolution Microwave Survey (HRMS) Investigator Working Group (IWG). As a (HRMS) Team Member with primary interest in the Sky Survey activity, this investigator attended IWG meetings at NASA/Ames and U.C.-Santa Cruz in Apr. and Aug. 1992, and has traveled independently to NRAO/Kitt Peak, Arizona (April 1993) and Woodbury, Georgia (July 1993). During the July 1993 visit to the Georgia Tech Research Corporation/Woodbury Research Facility, an experiment was conducted to study the effects of interference from C-band (3.7 - 4.2 GHz) geostationary spacecraft on the Sky Survey operation in that band. At the first IWG meeting in April of this year, results of a SETI observation conducted at the 203 GHz positronium hyperfine resonance using the NRAO facility at Kitt Peak, AZ, were presented, as well as updates on the development of the spaceborne RFI data bases developed for the project. At the second meeting, results of the study of interference from C-band geostationary spacecraft were presented. Likewise, a presentation was made at the accompanying 1993 Bioastronomy Symposium describing the SETI observation at the positronium hyperfine resonance.

  3. Object-based assessment of burn severity in diseased forests using high-spatial and high-spectral resolution MASTER airborne imagery

    Science.gov (United States)

    Chen, Gang; Metz, Margaret R.; Rizzo, David M.; Dillon, Whalen W.; Meentemeyer, Ross K.

    2015-04-01

    Forest ecosystems are subject to a variety of disturbances with increasing intensities and frequencies, which may permanently change the trajectories of forest recovery and disrupt the ecosystem services provided by trees. Fire and invasive species, especially exotic disease-causing pathogens and insects, are examples of disturbances that together could pose major threats to forest health. This study examines the impacts of fire and exotic disease (sudden oak death) on forests, with an emphasis on the assessment of post-fire burn severity in a forest where trees have experienced three stages of disease progression pre-fire: early-stage (trees retaining dried foliage and fine twigs), middle-stage (trees losing fine crown fuels), and late-stage (trees falling down). The research was conducted by applying Geographic Object-Based Image Analysis (GEOBIA) to MASTER airborne images that were acquired immediately following the fire for rapid assessment and contained both high-spatial (4 m) and high-spectral (50 bands) resolutions. Although GEOBIA has gradually become a standard tool for analyzing high-spatial resolution imagery, high-spectral resolution data (dozens to hundreds of bands) can dramatically reduce computation efficiency in the process of segmentation and object-based variable extraction, leading to complicated variable selection for succeeding modeling. Hence, we also assessed two widely used band reduction algorithms, PCA (principal component analysis) and MNF (minimum noise fraction), for the delineation of image objects and the subsequent performance of burn severity models using either PCA or MNF derived variables. To increase computation efficiency, only the top 5 PCA and MNF and top 10 PCA and MNF components were evaluated, which accounted for 10% and 20% of the total number of the original 50 spectral bands, respectively. Results show that if no band reduction was applied the models developed for the three stages of disease progression had relatively

  4. First high-resolution near-seafloor survey of magnetic anomalies of the South China Sea

    Science.gov (United States)

    Lin, J.; Xu, X.; Li, C.; Sun, Z.; Zhu, J.; Zhou, Z.; Qiu, N.

    2013-12-01

    We successfully conducted the first high-resolution near-seafloor magnetic survey of the Central, Southwest, and Northern Central Basins of the South China Sea (SCS) during two cruises on board Chinese R/V HaiYangLiuHao in October-November 2012 and March-April 2013, respectively. Measurements of magnetic field were made along four long survey lines, including (1) a NW-SE across-isochron profile transecting the Southwest Basin and covering all ages of the oceanic crust (Line CD); (2) a N-S across-isochron profile transecting the Central Basin (Line AB); and (3) two sub-parallel NE-SW across-isochron profiles transecting the Northern Central Basin of the SCS (Lines D and E). A three-axis magnetometer was mounted on a deep-tow vehicle, flying within 0.6 km above the seafloor. The position of the tow vehicle was provided by an ultra-short baseline navigation system along Lines D and E, while was estimated using shipboard GPS along Lines AB and CD. To investigate crustal magnetization, we first removed the International Geomagnetic Reference Field (IGRF) of 2010 from the measured magnetic data, and then downward continued the resultant magnetic field data to a horizontal plane at a water depth of 4.5 km to correct for variation due to the fishing depth of the deep-tow vehicle. Finally, we calculated magnetic anomalies at various water depths after reduction-to-the-pole corrections. We also constructed polarity reversal block (PRB) models of crustal magnetization by matching peaks and troughs of the observed magnetic field anomaly. Our analysis yielded the following results: (1) The near-bottom magnetic anomaly showed peak-to-trough amplitudes of more than 2,500 nT, which are several times of the anomaly amplitudes at the sea surface, illustrating that deep-tow measurements acquired much higher spatial resolutions. (2) The deep-tow data revealed several distinctive magnetic anomalies with wavelengths of 5-15 km and amplitudes of several hundred nT. These short

  5. Deep 20-GHz survey of the Chandra Deep Field South and SDSS Stripe 82: source catalogue and spectral properties

    Science.gov (United States)

    Franzen, Thomas M. O.; Sadler, Elaine M.; Chhetri, Rajan; Ekers, Ronald D.; Mahony, Elizabeth K.; Murphy, Tara; Norris, Ray P.; Waldram, Elizabeth M.; Whittam, Imogen H.

    2014-04-01

    We present a source catalogue and first results from a deep, blind radio survey carried out at 20 GHz with the Australia Telescope Compact Array, with follow-up observations at 5.5, 9 and 18 GHz. The Australia Telescope 20 GHz (AT20G) deep pilot survey covers a total area of 5 deg2 in the Chandra Deep Field South and in Stripe 82 of the Sloan Digital Sky Survey. We estimate the survey to be 90 per cent complete above 2.5 mJy. Of the 85 sources detected, 55 per cent have steep spectra (α _{1.4}^{20} law spectra between 1.4 and 18 GHz, while the spectral indices of the flat- or inverted-spectrum sources tend to steepen with frequency. Among the 18 inverted-spectrum (α _{1.4}^{20} ≥ 0.0) sources, 10 have clearly defined peaks in their spectra with α _{1.4}^{5.5} > 0.15 and α 9^{18} Cambridge and Tenth Cambridge surveys: there is a shift towards a steeper-spectrum population when going from ˜1 Jy to ˜5 mJy, which is followed by a shift back towards a flatter-spectrum population below ˜5 mJy. The 5-GHz source-count model by Jackson & Wall, which only includes contributions from FRI and FRII sources, and star-forming galaxies, does not reproduce the observed flattening of the flat-spectrum counts below ˜5 mJy. It is therefore possible that another population of sources is contributing to this effect.

  6. Can the periodic spectral modulations observed in 236 Sloan Sky Survey stars be due to dark matter effects?

    Science.gov (United States)

    Tamburini, Fabrizio; Licata, Ignazio

    2017-09-01

    The search for dark matter (DM) is one of the most active and challenging areas of current research. Possible DM candidates are ultralight fields such as axions and weak interacting massive particles (WIMPs). Axions piled up in the center of stars are supposed to generate matter/DM configurations with oscillating geometries at a very rapid frequency, which is a multiple of the axion mass m B (Brito et al (2015); Brito et al (2016)). Borra and Trottier (2016) recently found peculiar ultrafast periodic spectral modulations in 236 main sequence stars in the sample of 2.5 million spectra of galactic halo stars of the Sloan Digital Sky Survey (˜1% of main sequence stars in the F-K spectral range) that were interpreted as optical signals from extraterrestrial civilizations, suggesting them as possible candidates for the search for extraterrestrial intelligence (SETI) program. We argue, instead, that this could be the first indirect evidence of bosonic axion-like DM fields inside main sequence stars, with a stable radiative nucleus, where a stable DM core can be hosted. These oscillations were not observed in earlier stellar spectral classes probably because of the impossibility of starting a stable oscillatory regime due to the presence of chaotic motions in their convective nuclei. The axion mass values, (50< {m}B< 2.4× {10}3) μ {eV}, obtained from the frequency range observed by Borra and Trottier, (0.6070< f< 0.6077) THz, agree with the recent theoretical results from high-temperature lattice quantum chromodynamics (Borsanyi et al (2016); Borsanyi et al (2016b)).

  7. The Einstein@Home Gamma-ray Pulsar Survey. II. Source Selection, Spectral Analysis, and Multiwavelength Follow-up

    Science.gov (United States)

    Wu, J.; Clark, C. J.; Pletsch, H. J.; Guillemot, L.; Johnson, T. J.; Torne, P.; Champion, D. J.; Deneva, J.; Ray, P. S.; Salvetti, D.; Kramer, M.; Aulbert, C.; Beer, C.; Bhattacharyya, B.; Bock, O.; Camilo, F.; Cognard, I.; Cuéllar, A.; Eggenstein, H. B.; Fehrmann, H.; Ferrara, E. C.; Kerr, M.; Machenschalk, B.; Ransom, S. M.; Sanpa-Arsa, S.; Wood, K.

    2018-02-01

    We report on the analysis of 13 gamma-ray pulsars discovered in the Einstein@Home blind search survey using Fermi Large Area Telescope (LAT) Pass 8 data. The 13 new gamma-ray pulsars were discovered by searching 118 unassociated LAT sources from the third LAT source catalog (3FGL), selected using the Gaussian Mixture Model machine-learning algorithm on the basis of their gamma-ray emission properties being suggestive of pulsar magnetospheric emission. The new gamma-ray pulsars have pulse profiles and spectral properties similar to those of previously detected young gamma-ray pulsars. Follow-up radio observations have revealed faint radio pulsations from two of the newly discovered pulsars and enabled us to derive upper limits on the radio emission from the others, demonstrating that they are likely radio-quiet gamma-ray pulsars. We also present results from modeling the gamma-ray pulse profiles and radio profiles, if available, using different geometric emission models of pulsars. The high discovery rate of this survey, despite the increasing difficulty of blind pulsar searches in gamma rays, suggests that new systematic surveys such as presented in this article should be continued when new LAT source catalogs become available.

  8. The Arizona Radio Observatory 1 mm Spectral Survey of IRC (plus)10216 and VY Canis Majoris (215-285 GHz)

    Science.gov (United States)

    Tenenbaum, E. D.; Dodd, J. L.; Milam, S. N.; Woolf, N. J.; Ziurys, L. M.

    2010-01-01

    A low noise (1(sigma) rms approx. 3 mK) 1. nun spectral survey (214.5-285.5 GHz) of the oxygen-rich supergiant VY Canis Majoris and the carbon-rich asymptotic giant branch star IRC +10216 has been conducted using the Arizona Radio Observatory's 10 m Submillimeter Telescope. Here the complete data set is presented. This study, carried out with a new ALMA-type receiver, marks the first continuous band scan of an O-rich circumstellar envelope, and the most sensitive survey to date of IRC +10216. In VY CMa, 130 distinct molecular lines were detected, 14 of which cannot be identified; in IRC +10216, 717 lines were observed, with 126 features remaining unidentified. In the 1 mm bands of VY CMa and IRC +10216, emission is present from 18 and 32 different chemical compounds, respectively, with 10 species common to both sources. Many narrow emission lines were observed in both circumstellar shells, arising from vibrationally excited molecules and from refractory-containing species. Line profiles in VY CMa also exhibit a variety of different shapes, caused by the complex, asymmetric outflow of this object. The survey highlights the fact that C-rich and O-rich circumstellar envelopes are chemically interesting, and both are sources of new interstellar molecules. The high number of unidentified lines and the unreliable, rest frequencies for known species such as NaCN indicate the need for additional laboratory spectroscopy studies.

  9. The Arizona Radio Observatory 1 mm Spectral Survey of IRC +10216 and VY Canis Majoris (215-285 GHz)

    Science.gov (United States)

    Tenenbaum, E. D.; Dodd, J. L.; Milam, S. N.; Woolf, N. J.; Ziurys, L. M.

    2010-10-01

    A low noise (1σ rms ~ 3 mK) 1 mm spectral survey (214.5-285.5 GHz) of the oxygen-rich supergiant VY Canis Majoris and the carbon-rich asymptotic giant branch star IRC +10216 has been conducted using the Arizona Radio Observatory's 10 m Submillimeter Telescope. Here the complete data set is presented. This study, carried out with a new ALMA-type receiver, marks the first continuous band scan of an O-rich circumstellar envelope, and the most sensitive survey to date of IRC +10216. In VY CMa, 130 distinct molecular lines were detected, 14 of which cannot be identified; in IRC +10216, 717 lines were observed, with 126 features remaining unidentified. In the 1 mm bands of VY CMa and IRC +10216, emission is present from 18 and 32 different chemical compounds, respectively, with 10 species common to both sources. Many narrow emission lines were observed in both circumstellar shells, arising from vibrationally excited molecules and from refractory-containing species. Line profiles in VY CMa also exhibit a variety of different shapes, caused by the complex, asymmetric outflow of this object. The survey highlights the fact that C-rich and O-rich circumstellar envelopes are chemically interesting, and both are sources of new interstellar molecules. The high number of unidentified lines and the unreliable rest frequencies for known species such as NaCN indicate the need for additional laboratory spectroscopy studies.

  10. THE ARIZONA RADIO OBSERVATORY 1 mm SPECTRAL SURVEY OF IRC +10216 AND VY CANIS MAJORIS (215-285 GHz)

    International Nuclear Information System (INIS)

    Tenenbaum, E. D.; Dodd, J. L.; Woolf, N. J.; Ziurys, L. M.; Milam, S. N.

    2010-01-01

    A low noise (1σ rms ∼ 3 mK) 1 mm spectral survey (214.5-285.5 GHz) of the oxygen-rich supergiant VY Canis Majoris and the carbon-rich asymptotic giant branch star IRC +10216 has been conducted using the Arizona Radio Observatory's 10 m Submillimeter Telescope. Here the complete data set is presented. This study, carried out with a new ALMA-type receiver, marks the first continuous band scan of an O-rich circumstellar envelope, and the most sensitive survey to date of IRC +10216. In VY CMa, 130 distinct molecular lines were detected, 14 of which cannot be identified; in IRC +10216, 717 lines were observed, with 126 features remaining unidentified. In the 1 mm bands of VY CMa and IRC +10216, emission is present from 18 and 32 different chemical compounds, respectively, with 10 species common to both sources. Many narrow emission lines were observed in both circumstellar shells, arising from vibrationally excited molecules and from refractory-containing species. Line profiles in VY CMa also exhibit a variety of different shapes, caused by the complex, asymmetric outflow of this object. The survey highlights the fact that C-rich and O-rich circumstellar envelopes are chemically interesting, and both are sources of new interstellar molecules. The high number of unidentified lines and the unreliable rest frequencies for known species such as NaCN indicate the need for additional laboratory spectroscopy studies.

  11. VizieR Online Data Catalog: Spectral line survey of two LOSs (Armijos-Abendano+, 2015)

    Science.gov (United States)

    Armijos-Abendano, J.; Martin-Pintado, J.; Requena-Torres, M. A.; Martin, S.; Rodriguez-Franco, A.

    2017-11-01

    The observations were carried out with the 22-m Mopra radio telescope in November 2007. We used the dual 3-mm Monolithic Microwave Integrated Circuit (MMIC) receiver connected to the 8-GHz spectrometer, which provided a velocity resolution of ~0.9 km/s at 90 GHz. Spectra in two polarizations were observed simultaneously. Two frequency ranges in the 3-mm window were covered, ~77-93 GHz and ~105-113 GHz. The beam size of the telescope was 38 arcsec at 90 GHz and 30 arcsec at 115 GHz. (3 data files).

  12. Enhanced spectral resolution by high-dimensional NMR using the filter diagonalization method and “hidden” dimensions

    Science.gov (United States)

    Meng, Xi; Nguyen, Bao D.; Ridge, Clark; Shaka, A. J.

    2009-01-01

    High-dimensional (HD) NMR spectra have poorer digital resolution than low-dimensional (LD) spectra, for a fixed amount of experiment time. This has led to “reduced-dimensionality” strategies, in which several LD projections of the HD NMR spectrum are acquired, each with higher digital resolution; an approximate HD spectrum is then inferred by some means. We propose a strategy that moves in the opposite direction, by adding more time dimensions to increase the information content of the data set, even if only a very sparse time grid is used in each dimension. The full HD time-domain data can be analyzed by the Filter Diagonalization Method (FDM), yielding very narrow resonances along all of the frequency axes, even those with sparse sampling. Integrating over the added dimensions of HD FDM NMR spectra reconstitutes LD spectra with enhanced resolution, often more quickly than direct acquisition of the LD spectrum with a larger number of grid points in each of the fewer dimensions. If the extra dimensions do not appear in the final spectrum, and are used solely to boost information content, we propose the moniker hidden-dimension NMR. This work shows that HD peaks have unmistakable frequency signatures that can be detected as single HD objects by an appropriate algorithm, even though their patterns would be tricky for a human operator to visualize or recognize, and even if digital resolution in an HD FT spectrum is very coarse compared with natural line widths. PMID:18926747

  13. High-resolution measurement, line identification, and spectral modeling of the Kβ spectrum of heliumlike argon emitted by a laser-produced plasma using a gas-puff target

    International Nuclear Information System (INIS)

    Skobelev, I.Y.; Faenov, A.Y.; Dyakin, V.M.; Fiedorowicz, H.; Bartnik, A.; Szczurek, M.; Beiersdorfer, P.; Nilsen, J.; Osterheld, A.L.

    1997-01-01

    We present an analysis of the spectrum of satellite transitions to the He-β line in ArXVII. High-resolution measurements of the spectra from laser-heated Ar-gas-puff targets are made with spectral resolution of 10000 and spatial resolution of better than 50 μm. These are compared with tokamak measurements. Several different lines are identified in the spectra and the spectral analysis is used to determine the plasma parameters in the gas-puff laser-produced plasma. The data complement those from tokamak measurements to provide more complete information on the satellite spectra. copyright 1997 The American Physical Society

  14. Spectral and spatial resolution properties of photon counting X-ray detectors like the Medipix-Detector

    International Nuclear Information System (INIS)

    Korn, A.

    2007-01-01

    The Medipix detector is a hybrid photon counting X-ray detector, consisting of an ASIC and a semiconducting layer as the sensor. This makes the Medipix a direct converting detector. A special feature of the Medipix is a signal processing circuit in every single pixel. This circuit amplifies the input signal triggered by a photon and then transforms the pulse into a digital signal. This early stage digitalisation is one of the main advantages of the detector, since no dark currents are integrated into the signal. Furthermore, the energy information of each single photon is partly preserved. The high number of pixels lends the detector a wide dynamic range, starting from single counts up to a rate of 1010 photons per cm2 and second. Apart from the many advantages, there are still some problems with the detector. Some effects lead to a deterioration of the energy resolution as well as the spatial resolution. The main reasons for this are two effects occuring in the detector, charge sharing and backscattering inside the detector. This study investigates the influence of those two effects on both the energy and spatial resolution. The physical causes of these effects are delineated and their impact on the detector output is examined. In contrast to high energy photon detectors, the repulsion of the charge carriers drifting inside the sensor must not be neglected in a detailed model of X-ray detectors with an energy range of 5 keV-200 keV. For the simulation of the Medipix using Monte Carlo simulations, the software ROSI was augmented. The added features allow a detailed simulation of the charge distribution, using the relevant physical effects that alter the distribution width during the drift towards the sensor electrodes as well further influences on the detector output, including electronical noise, threshold noise or the geometry of the detector. The measured energy and spatial resolution of several different models of Medipix is compared to the simulated

  15. Galactic and stellar dynamics in the era of high resolution surveys

    Science.gov (United States)

    Boily, C. M.; Combes, F.; Hensler, G.; Spurzem, R.

    2008-12-01

    The conference Galactic and Stellar Dynamics in the Era of High Resolution Surveys took place at the European Doctoral College (EDC) in Strasbourg from 2008 March 16 to 20. The event was co-sponsored by the Astronomische Gesellschaft (AG) and the Société Fran\\c{c}aise d'Astronomie et d'Astrophysique (SF2A), a joint venture aiming to set a new trend of regular thematic meetings in specific areas of research. This special issue of the Astronomische Nachrichten is a compilation of the papers presented at the meeting. We give an outline of the meeting together with a short history of the relations of the two societies.

  16. THE HERSCHEL AND IRAM CHESS SPECTRAL SURVEYS OF THE PROTOSTELLAR SHOCK L1157-B1: FOSSIL DEUTERATION

    International Nuclear Information System (INIS)

    Codella, C.; Fontani, F.; Vasta, M.; Ceccarelli, C.; Lefloch, B.; Kahane, C.; Taquet, V.; Wiesenfeld, L.; Busquet, G.; Caselli, P.; Lis, D.; Viti, S.

    2012-01-01

    We present the first study of deuteration toward the protostellar shock L1157-B1, based on spectral surveys performed with the Herschel-HIFI and IRAM 30 m telescopes. The L1157 outflow is driven by a low-mass Class 0 protostar and is considered the prototype of the so-called chemically active outflows. The young (2000 yr), bright blueshifted bow shock, B1, is an ideal laboratory for studying the gas chemically enriched by the release of dust mantles due to the passage of a shock. A total of 12 emission lines (up to E u = 63 K) of CH 2 DOH, HDCO, and DCN are detected. In addition, two lines of NH 2 D and HDO are tentatively reported. To estimate the deuteration, we also extracted from our spectral survey emission lines of non-deuterated isotopologues ( 13 CH 3 OH, H 2 13 CO, H 13 CN, H 2 13 CO, and NH 3 ). We infer higher deuteration fractions for CH 3 OH (D/H = 0.2-2 × 10 –2 ) and H 2 CO (5-8 × 10 –3 ) than for H 2 O (0.4-2 × 10 –3 ), HCN (∼10 –3 ), and ammonia (≤3 × 10 –2 ). The measurement of deuteration of water, formaldehyde, and methanol in L1157-B1 provides a fossil record of the gas before it was shocked by the jet driven by the protostar. A comparison with gas-grain models indicates that the gas passed through a low-density (≤10 3 cm –3 ) phase, during which the bulk of water ices formed, followed by a phase of increasing density, up to 3 × 10 4 cm –3 , during which formaldehyde and methanol ices formed.

  17. Survey of the spectral irradiance distribution of fluorescent tubes for solaria

    International Nuclear Information System (INIS)

    Johnsen, B.; Hannevik, M.

    1993-01-01

    The report describes a systematic mapping of the spectral irradiance distribution of typical fluorescent tubes, emitting ultraviolet radiation (UVR). The spectra were multiplied with biological action curves for assessing their potential for acute harmful effects. Comparing values of effective irradiance revealed a difference by a factor of ten between tubes for cosmetic UVR-treatment. Comparing spectra of the strongest cosmetic types with the spectrum of a typical tube for medical UVR-treatment revealed another factor of ten in effective irradiance. Spectra of typical cosmetic solarium tubes and natural sun at summer in Oslo are shown to be closely related in the UV-region, thereby justifying the term artificial sunlamps. Threshold limit values and action curves, as expressed in the former Norwegian solarium prescriptions from 1983 and the CENELEC standard for classifying UVR-emitting appliance, were compared. Calculations have shown that an adoption of the CENELEC threshold limit values will be more restrictive on the short-wave UV-region, while they generally will be similar, or a bit less restrictive on the longwave UV-region. 3 refs., 45 figs., 6 tabs

  18. Ground-based eye-safe networkable micro-pulse differential absorption and high spectral resolution lidar for water vapor and aerosol profiling in the lower troposphere

    Science.gov (United States)

    Repasky, K. S.; Spuler, S.; Hayman, M. M.; Bunn, C. E.

    2017-12-01

    Atmospheric water vapor is a greenhouse gas that is known to be a significant driver of weather and climate. Several National Research Council (NRC) reports have highlighted the need for improved water vapor measurements that can capture its spatial and temporal variability as a means to improve weather predictions. Researchers at Montana State University (MSU) and the National Center for Atmospheric Research (NCAR) have developed an eye-safe diode laser based micro-pulse differential absorption lidar (MP-DIAL) for water vapor profiling in the lower troposphere. The MP-DIAL is capable of long term unattended operation and is capable of monitoring water vapor in the lower troposphere in most weather conditions. Two MP-DIAL instruments are currently operational and have been deployed at the Front Range Air Pollution and Photochemistry Experiment (FRAPPE), the Plains elevated Convection at Night (PECAN) experiment, the Perdigão experiment, and the Land Atmosphere Feedback Experiment (LAFE). For each of these field experiments, the MP-DIAL was run unattended and provided near-continuous water vapor profiles, including periods of bright daytime clouds, from 300 m above the ground level to 4 km (or the cloud base) with 150 m vertical resolution and 5 minute temporal resolution. Three additional MP-DIAL instruments are currently under construction and will result in a network of five eye-safe MP-DIAL instruments for ground based weather and climate research experiments. Taking advantage of the broad spectral coverage and modularity or the diode based architecture, a high spectral resolution lidar (HSRL) measurement capabilities was added to the second MP-DIAL instrument. The HSRL capabilities will be operational during the deployment at the LAFE field experiment. The instrument architecture will be presented along with examples of data collected during recent field experiments.

  19. WHY IS NON-THERMAL LINE BROADENING OF SPECTRAL LINES IN THE LOWER TRANSITION REGION OF THE SUN INDEPENDENT OF SPATIAL RESOLUTION?

    International Nuclear Information System (INIS)

    De Pontieu, B.; Martinez-Sykora, J.; McIntosh, S.; Peter, H.; Pereira, T. M. D.

    2015-01-01

    Spectral observations of the solar transition region (TR) and corona show broadening of spectral lines beyond what is expected from thermal and instrumental broadening. The remaining non-thermal broadening is significant (5–30 km s −1 ) and correlated with intensity. Here we study spectra of the TR Si iv 1403 Å line obtained at high resolution with the Interface Region Imaging Spectrograph (IRIS). We find that the large improvement in spatial resolution (0.″33) of IRIS compared to previous spectrographs (2″) does not resolve the non-thermal line broadening which, in most regions, remains at pre-IRIS levels of about 20 km s −1 . This invariance to spatial resolution indicates that the processes behind the broadening occur along the line-of-sight (LOS) and/or on spatial scales (perpendicular to the LOS) smaller than 250 km. Both effects appear to play a role. Comparison with IRIS chromospheric observations shows that, in regions where the LOS is more parallel to the field, magneto-acoustic shocks driven from below impact the TR and can lead to significant non-thermal line broadening. This scenario is supported by MHD simulations. While these do not show enough non-thermal line broadening, they do reproduce the long-known puzzling correlation between non-thermal line broadening and intensity. This correlation is caused by the shocks, but only if non-equilibrium ionization is taken into account. In regions where the LOS is more perpendicular to the field, the prevalence of small-scale twist is likely to play a significant role in explaining the invariance and correlation with intensity. (letters)

  20. Chromospheric activity of periodic variable stars (including eclipsing binaries) observed in DR2 LAMOST stellar spectral survey

    Science.gov (United States)

    Zhang, Liyun; Lu, Hongpeng; Han, Xianming L.; Jiang, Linyan; Li, Zhongmu; Zhang, Yong; Hou, Yonghui; Wang, Yuefei; Cao, Zihuang

    2018-05-01

    The LAMOST spectral survey provides a rich databases for studying stellar spectroscopic properties and chromospheric activity. We cross-matched a total of 105,287 periodic variable stars from several photometric surveys and databases (CSS, LINEAR, Kepler, a recently updated eclipsing star catalogue, ASAS, NSVS, some part of SuperWASP survey, variable stars from the Tsinghua University-NAOC Transient Survey, and other objects from some new references) with four million stellar spectra published in the LAMOST data release 2 (DR2). We found 15,955 spectra for 11,469 stars (including 5398 eclipsing binaries). We calculated their equivalent widths (EWs) of their Hα, Hβ, Hγ, Hδ and Caii H lines. Using the Hα line EW, we found 447 spectra with emission above continuum for a total of 316 stars (178 eclipsing binaries). We identified 86 active stars (including 44 eclipsing binaries) with repeated LAMOST spectra. A total of 68 stars (including 34 eclipsing binaries) show chromospheric activity variability. We also found LAMOST spectra of 12 cataclysmic variables, five of which show chromospheric activity variability. We also made photometric follow-up studies of three short period targets (DY CVn, HAT-192-0001481, and LAMOST J164933.24+141255.0) using the Xinglong 60-cm telescope and the SARA 90-cm and 1-m telescopes, and obtained new BVRI CCD light curves. We analyzed these light curves and obtained orbital and starspot parameters. We detected the first flare event with a huge brightness increase of more than about 1.5 magnitudes in R filter in LAMOST J164933.24+141255.0.

  1. Remote detection of fluid-related diagenetic mineralogical variations in the Wingate Sandstone at different spatial and spectral resolutions

    Science.gov (United States)

    Okyay, Unal; Khan, Shuhab D.

    2016-02-01

    Well-exposed eolian units of the Jurassic system on the Colorado Plateau including the Wingate Sandstone, show prominent color variations throughout southeastern Utah due to diagenetic changes that include precipitation and/or removal of iron oxide, clay, and carbonate cement. Spatially variable characteristic diagenetic changes suggest fluid-rock interactions through the sandstone. Distinctive spectral signatures of diagenetic minerals can be used to map diagenetic mineral variability and possibly fluid-flow pathways. The main objective of this work was to identify characteristic diagenetic minerals, and map their spatial variability from regional to outcrop scale in Wingate Sandstone exposures of Lisbon Valley, Utah. Laboratory reflectance spectroscopy analysis of the samples facilitated identification of diagnostic spectral characteristics of the common diagenetic minerals and their relative abundances between altered and unaltered Wingate Sandstone. Comparison of reflectance spectroscopy with satellite, airborne, and ground-based imaging spectroscopy data provided a method for mapping and evaluating spatial variations of diagenetic minerals. The Feature-oriented Principal Component Selection method was used on Advanced Spaceborne Thermal Emission and Reflection Radiometer data so as to map common mineral groups throughout the broader Wingate Sandstone exposure in the area. The Minimum Noise Fraction and Spectral Angle Mapper methods were applied on airborne HyMap and ground-based hyperspectral imaging data to identify and map mineralogical changes. The satellite and airborne data showed that out of 25.55 km2 total exposure of Wingate Sandstone in Lisbon Valley, unaltered sandstone cover 12.55 km2, and altered sandstone cover 8.90 km2 in the northwest flank and 5.09 km2 in the southern flank of the anticline. The ground-based hyperspectral data demonstrated the ability to identify and map mineral assemblages with two-dimensional lateral continuity on near

  2. In-situ high-resolution gamma-spectrometric survey of burial ground-monitoring wells

    International Nuclear Information System (INIS)

    Bowman, W.W.

    1981-09-01

    In situ high resolution gamma-ray spectrometry with an intrinsic germanium detector assembly of special design surveyed the burial ground monitoring wells to locate and identify gamma emitters that may have migrated from the burial trenches toward the water table. Gamma-ray spectra were acquired as a function of depth in each well and recorded on magnetic tape. These spectra were reduced by a series of computer programs to produce count rate versus depth profiles for natural and man-made activities. The original spectra and the profiles have been archived on magnetic tape for comparison with similar future surveys. Large amounts of man-made activities were observed in some of the burial trenches; however, below the trench bottoms, only very low but detectable amounts of 60 Co and 137 Cs were observed in eleven wells. The highest level of man-made gamma activity observed below the trench bottoms has a count rate roughly equal to that observed for uranium daughter activities which are natural to the subsoil

  3. The BAT AGN Spectroscopic Survey (BASS) DR1-Spectral Measurements, Derived Quantities, and AGN Demographics

    Science.gov (United States)

    Koss, Michael; BASS Team

    2018-01-01

    We present the first catalog and data release of the Swift-BAT AGN Spectroscopic Survey (BASS). We analyze optical spectra of the majority of AGN (77%, 641/836) detected based on their 14-195 keV emission in the 70-month Swift BAT all-sky catalog. This includes redshift determination, absorption and emission line measurements, and black hole mass and accretion rate estimates for the majority of obscured and un-obscured AGN (74%, 473/641) with 340 measured for the first time. With ~90% of sources at z10^21.9 cm^-2. Seyfert 1.9 show a range of column densities. Compared to narrow line AGN in the SDSS, the X-ray selected AGN have a larger fraction of dusty host galaxies suggesting these types of AGN are missed in optical surveys. Using the most sensitive [OIII]/Hbeta and [NII]/Halpha emission line diagnostic, about half of the sources are classified as Seyferts, ~15% reside in dusty galaxies that lack an Hbeta detection, but for which the line upper limits imply either a Seyfert or LINER, ~15% are in galaxies with weak or no emission lines despite high quality spectra, and a few percent each are LINERS, composite galaxies, HII regions, or in known beamed AGN.

  4. High-Resolution Aeromagnetic Survey over the Yucatan Peninsula - Implications for Chicxulub Impact, Secondary Craters and Regional Crustal Structures

    Science.gov (United States)

    Fucugauchi, J. U.; Lopez-Loera, H.; Rebolledo-Vieyra, M.

    2011-12-01

    We present the initial results of a low-altitude high-resolution aeromagnetic study over the Yucatan peninsula. Area surveyed extends from 86W to 91W and 18N to 21N, covering the peninsula and adjacent continental margin of Gulf of Mexico and Caribbean Sea. Aeromagnetic surveys are integrated into a regional map, and regional and residual anomalies are separated using spectral and least-squares methods. For the study, aeromagnetic field was reduced to the pole and several data filtering techniques were used, including first and second vertical derivatives, analytical signal, and upward and downward analytical continuations. The region is characterized by large amplitude broad elongated magnetic anomalies oriented north-south in the northern sector of the continental shelf, and northwest-southeast and northeast-southwest over the western and eastern sides of the peninsula, respectively. Major regional anomalies extend from the continental shelf into the peninsula, whereas other anomaly trends in the central northern sector, at northeast limit of Chicxulub crater, are restricted to the shelf. Largest anomaly on the east extends over the Holbox fracture zone. At its southern end, south of Chetumal a parallel trend extends over the Rio Hondo fault zone between Quintana Roo and Belize. On the western peninsula the anomaly is characterized by two parallel trends offset between Yucatan and Campeche. The central zone of Chicxulub is characterized by a semi-circular anomaly pattern, surrounded by long wavelength small amplitude anomalies extending to the east on the peninsula and shelf, isolated from the regional broad anomalies. To the south of Chicxulub anomaly, there is an elongated low with a central high extending southward from the terrace zone inside the crater rim. The elongated magnetic anomaly correlates with a broad gravity low, which is apparent south of the concentric zone of anomalies. To the north of Chicxulub anomaly, a magnetic high inside the crater is

  5. An unbiased spectral line survey toward R CrA IRS7B in the 345 GHz window with ASTE

    DEFF Research Database (Denmark)

    Watanabe, Yoshimasa; Sakai, Nami; Lindberg, Johan

    2012-01-01

    We have conducted a spectral line survey in the 332-364 GHz region with the Atacama Submillimeter Telescope Experiment 10 m telescope toward R CrA IRS7B, a low-mass protostar in the Class 0 or Class 0/I transitional stage. We have also performed some supplementary observations in the 450 GHz band...... corino. These results suggest a weak hot corino activity in R CrA IRS7B. On the other hand, the carbon-chain related molecules, CCH and c-C3H2, are found to be abundant. However, this source cannot be classified as a WCCC source, since long carbon-chain molecules are not detected. If WCCC and hot corino...... chemistry represent the two extremes in chemical compositions of low-mass Class 0 sources, R CrA IRS7B would be a source with a mixture of these two chemical characteristics. The UV radiation from the nearby Herbig Ae star R CrA may also affect the chemical composition. The present line survey demonstrates...

  6. Spectral survey of helium lines in a linear plasma device for use in HELIOS imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ray, H. B., E-mail: rayhb@ornl.gov [University of Tennessee, Knoxville, Tennessee 37996 (United States); Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Biewer, T. M.; Fehling, D. T.; Isler, R. C.; Unterberg, E. A. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2016-11-15

    Fast visible cameras and a filterscope are used to examine the visible light emission from Oak Ridge National Laboratory’s Proto-MPEX. The filterscope has been configured to perform helium line ratio measurements using emission lines at 667.9, 728.1, and 706.5 nm. The measured lines should be mathematically inverted and the ratios compared to a collisional radiative model (CRM) to determine T{sub e} and n{sub e}. Increasing the number of measurement chords through the plasma improves the inversion calculation and subsequent T{sub e} and n{sub e} localization. For the filterscope, one spatial chord measurement requires three photomultiplier tubes (PMTs) connected to pellicle beam splitters. Multiple, fast visible cameras with narrowband filters are an alternate technique for performing these measurements with superior spatial resolution. Each camera contains millions of pixels; each pixel is analogous to one filterscope PMT. The data can then be inverted and the ratios compared to the CRM to determine 2-dimensional “images” of T{sub e} and n{sub e} in the plasma. An assessment is made in this paper of the candidate He I emission lines for an imaging technique.

  7. Spectral survey of helium lines in a linear plasma device for use in HELIOS imaging

    Science.gov (United States)

    Ray, H. B.; Biewer, T. M.; Fehling, D. T.; Isler, R. C.; Unterberg, E. A.

    2016-11-01

    Fast visible cameras and a filterscope are used to examine the visible light emission from Oak Ridge National Laboratory's Proto-MPEX. The filterscope has been configured to perform helium line ratio measurements using emission lines at 667.9, 728.1, and 706.5 nm. The measured lines should be mathematically inverted and the ratios compared to a collisional radiative model (CRM) to determine Te and ne. Increasing the number of measurement chords through the plasma improves the inversion calculation and subsequent Te and ne localization. For the filterscope, one spatial chord measurement requires three photomultiplier tubes (PMTs) connected to pellicle beam splitters. Multiple, fast visible cameras with narrowband filters are an alternate technique for performing these measurements with superior spatial resolution. Each camera contains millions of pixels; each pixel is analogous to one filterscope PMT. The data can then be inverted and the ratios compared to the CRM to determine 2-dimensional "images" of Te and ne in the plasma. An assessment is made in this paper of the candidate He I emission lines for an imaging technique.

  8. Investigations in the Spectral Properties of Operators with Distant Perturbations (survey

    Directory of Open Access Journals (Sweden)

    A. M. Golovina

    2015-01-01

    spectral properties of the operators:1 investigations into the eigenvalues and the corresponding eigenfunctions of the Laplaceoperator with distant potentials;(a in the case of a simple limit eigenvalue;(b in the case of a multiple limit eigenvalue;2 investigations into the resolvent of the Laplace operator with several distant potentials;3 investigations into asymptotic behavior of the eigenvalues arising from the edge of the essential spectrum of the unperturbed operator.In conclusion, we formulate open problems in this theory:1. What kind of behavior of the eigenvalues and the corresponding eigenfunctions arising from the edge of the essential spectrum? Under what conditions do they arise? What is their asymptotic expansion?2. What are the first members of perturbed eigenvalues in the case of an arbitrary finite number of distant perturbations?

  9. Numerical resolution of the Navier-Stokes equations for a low Mach number by a spectral method

    International Nuclear Information System (INIS)

    Frohlich, Jochen

    1990-01-01

    The low Mach number approximation of the Navier-Stokes equations, also called isobar, is an approximation which is less restrictive than the one due to Boussinesq. It permits strong density variations while neglecting acoustic phenomena. We present a numerical method to solve these equations in the unsteady, two dimensional case with one direction of periodicity. The discretization uses a semi-implicit finite difference scheme in time and a Fourier-Chebycheff pseudo-spectral method in space. The solution of the equations of motion is based on an iterative algorithm of Uzawa type. In the Boussinesq limit we obtain a direct method. A first application is concerned with natural convection in the Rayleigh-Benard setting. We compare the results of the low Mach number equations with the ones in the Boussinesq case and consider the influence of variable fluid properties. A linear stability analysis based on a Chebychev-Tau method completes the study. The second application that we treat is a case of isobaric combustion in an open domain. We communicate results for the hydrodynamic Darrieus-Landau instability of a plane laminar flame front. [fr

  10. Feasibility of modifying the high resolution infrared radiation sounder (HIRS/2) for measuring spectral components of Earth radiation budget

    Science.gov (United States)

    Koenig, E. W.; Holman, K. A.

    1980-01-01

    The concept of adding four spectral channels to the 20 channel HIRS/2 instrument for the purpose of determining the origin and profile of radiant existence from the Earth's atmosphere is considered. Methods of addition of three channels at 0.5, 1.0 and 1.6 micron m to the present 0.7 micron m visible channel and an 18-25 micron m channel to the present 19 channels spaced from 3.7 micron m to 15 micron m are addressed. Optical components and physical positions were found that permit inclusion of these added channels with negligible effect on the performance of the present 20 channels. Data format changes permit inclusion of the ERB data in the 288 bits allocated to HIRS for each scan element. A lamp and collimating optic assembly may replace one of the on board radiometric black bodies to provide a reference source for the albedo channels. Some increase in instrument dimensions, weight and power will be required to accommodate the modifications.

  11. Global Monitoring of Terrestrial Chlorophyll Fluorescence from Moderate-spectral-resolution Near-infrared Satellite Measurements: Methodology, Simulations, and Application to GOME-2

    Science.gov (United States)

    Joiner, J.; Gaunter, L.; Lindstrot, R.; Voigt, M.; Vasilkov, A. P.; Middleton, E. M.; Huemmrich, K. F.; Yoshida, Y.; Frankenberg, C.

    2013-01-01

    Globally mapped terrestrial chlorophyll fluorescence retrievals are of high interest because they can provide information on the functional status of vegetation including light-use efficiency and global primary productivity that can be used for global carbon cycle modeling and agricultural applications. Previous satellite retrievals of fluorescence have relied solely upon the filling-in of solar Fraunhofer lines that are not significantly affected by atmospheric absorption. Although these measurements provide near-global coverage on a monthly basis, they suffer from relatively low precision and sparse spatial sampling. Here, we describe a new methodology to retrieve global far-red fluorescence information; we use hyperspectral data with a simplified radiative transfer model to disentangle the spectral signatures of three basic components: atmospheric absorption, surface reflectance, and fluorescence radiance. An empirically based principal component analysis approach is employed, primarily using cloudy data over ocean, to model and solve for the atmospheric absorption. Through detailed simulations, we demonstrate the feasibility of the approach and show that moderate-spectral-resolution measurements with a relatively high signal-to-noise ratio can be used to retrieve far-red fluorescence information with good precision and accuracy. The method is then applied to data from the Global Ozone Monitoring Instrument 2 (GOME-2). The GOME-2 fluorescence retrievals display similar spatial structure as compared with those from a simpler technique applied to the Greenhouse gases Observing SATellite (GOSAT). GOME-2 enables global mapping of far-red fluorescence with higher precision over smaller spatial and temporal scales than is possible with GOSAT. Near-global coverage is provided within a few days. We are able to show clearly for the first time physically plausible variations in fluorescence over the course of a single month at a spatial resolution of 0.5 deg × 0.5 deg

  12. Global monitoring of terrestrial chlorophyll fluorescence from moderate-spectral-resolution near-infrared satellite measurements: methodology, simulations, and application to GOME-2

    Directory of Open Access Journals (Sweden)

    J. Joiner

    2013-10-01

    Full Text Available Globally mapped terrestrial chlorophyll fluorescence retrievals are of high interest because they can provide information on the functional status of vegetation including light-use efficiency and global primary productivity that can be used for global carbon cycle modeling and agricultural applications. Previous satellite retrievals of fluorescence have relied solely upon the filling-in of solar Fraunhofer lines that are not significantly affected by atmospheric absorption. Although these measurements provide near-global coverage on a monthly basis, they suffer from relatively low precision and sparse spatial sampling. Here, we describe a new methodology to retrieve global far-red fluorescence information; we use hyperspectral data with a simplified radiative transfer model to disentangle the spectral signatures of three basic components: atmospheric absorption, surface reflectance, and fluorescence radiance. An empirically based principal component analysis approach is employed, primarily using cloudy data over ocean, to model and solve for the atmospheric absorption. Through detailed simulations, we demonstrate the feasibility of the approach and show that moderate-spectral-resolution measurements with a relatively high signal-to-noise ratio can be used to retrieve far-red fluorescence information with good precision and accuracy. The method is then applied to data from the Global Ozone Monitoring Instrument 2 (GOME-2. The GOME-2 fluorescence retrievals display similar spatial structure as compared with those from a simpler technique applied to the Greenhouse gases Observing SATellite (GOSAT. GOME-2 enables global mapping of far-red fluorescence with higher precision over smaller spatial and temporal scales than is possible with GOSAT. Near-global coverage is provided within a few days. We are able to show clearly for the first time physically plausible variations in fluorescence over the course of a single month at a spatial resolution of 0

  13. ANALYSIS OF THE HERSCHEL /HEXOS SPECTRAL SURVEY TOWARD ORION SOUTH: A MASSIVE PROTOSTELLAR ENVELOPE WITH STRONG EXTERNAL IRRADIATION

    Energy Technology Data Exchange (ETDEWEB)

    Tahani, K.; Plume, R. [Department of Physics and Astronomy, University of Calgary, Calgary, AB T2N 1N4 (Canada); Bergin, E. A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Tolls, V. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Phillips, T. G.; Lis, D. C. [California Institute of Technology, Cahill Center for Astronomy and Astrophysics 301-17, Pasadena, CA 91125 (United States); Caux, E. [Université de Toulouse, UPS-OMP, IRAP, F-31028 Toulouse (France); Cabrit, S.; Pagani, L. [LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-75014, Paris (France); Goicoechea, J. R. [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid (Spain); Goldsmith, P. F.; Pearson, J. C. [Jet Propulsion Laboratory, Caltech, Pasadena, CA 91109 (United States); Johnstone, D. [National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Menten, K. M. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Müller, H. S. P.; Ossenkopf-Okada, V. [I. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln (Germany); Tak, F. F. S. van der, E-mail: ktahani@ucalgary.ca [SRON Netherlands Institute for Space Research, P.O. Box 800, 9700 AV, Groningen (Netherlands)

    2016-11-20

    We present results from a comprehensive submillimeter spectral survey toward the source Orion South, based on data obtained with the Heterodyne Instrument for the Far-Infrared instrument on board the Herschel Space Observatory , covering the frequency range of 480 to 1900 GHz. We detect 685 spectral lines with signal-to-noise ratios (S/Ns) > 3 σ , originating from 52 different molecular and atomic species. We model each of the detected species assuming conditions of Local Thermodynamic Equilibrium. This analysis provides an estimate of the physical conditions of Orion South (column density, temperature, source size, and V {sub LSR}). We find evidence for three different cloud components: a cool ( T {sub ex} ∼ 20–40 K), spatially extended (>60″), and quiescent (Δ V {sub FWHM} ∼ 4 km s{sup -1}) component; a warmer ( T {sub ex} ∼ 80–100 K), less spatially extended (∼30″), and dynamic (Δ V {sub FWHM} ∼ 8 km s{sup -1}) component, which is likely affected by embedded outflows; and a kinematically distinct region ( T {sub ex} > 100 K; V {sub LSR} ∼ 8 km s{sup -1}), dominated by emission from species that trace ultraviolet irradiation, likely at the surface of the cloud. We find little evidence for the existence of a chemically distinct “hot-core” component, likely due to the small filling factor of the hot core or hot cores within the Herschel beam. We find that the chemical composition of the gas in the cooler, quiescent component of Orion South more closely resembles that of the quiescent ridge in Orion-KL. The gas in the warmer, dynamic component, however, more closely resembles that of the Compact Ridge and Plateau regions of Orion-KL, suggesting that higher temperatures and shocks also have an influence on the overall chemistry of Orion South.

  14. HST HOT-JUPITER TRANSMISSION SPECTRAL SURVEY: CLEAR SKIES FOR COOL SATURN WASP-39b

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Patrick D.; Knutson, Heather A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Sing, David K.; Kataria, Tiffany; Nikolov, Nikolay [Astrophysics Group, School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL (United Kingdom); Henry, Gregory W.; Williamson, Michael W. [Center of Excellence in Information Systems, Tennessee State University, Nashville, TN 37209 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California Santa Cruz, CA 95064 (United States); Burrows, Adam S. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Showman, Adam P.; Ballester, Gilda E. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Désert, Jean-Michel [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Aigrain, Suzanne [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Etangs, Alain Lecavelier des; Vidal-Madjar, Alfred [CNRS, Institut dAstrophysique de Paris, UMR 7095, 98bis boulevard Arago, F-75014 Paris (France)

    2016-08-10

    We present the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) optical transmission spectroscopy of the cool Saturn-mass exoplanet WASP-39b from 0.29-1.025 μ m, along with complementary transit observations from Spitzer IRAC at 3.6 and 4.5 μ m. The low density and large atmospheric pressure scale height of WASP-39b make it particularly amenable to atmospheric characterization using this technique. We detect a Rayleigh scattering slope as well as sodium and potassium absorption features; this is the first exoplanet in which both alkali features are clearly detected with the extended wings predicted by cloud-free atmosphere models. The full transmission spectrum is well matched by a clear H{sub 2}-dominated atmosphere, or one containing a weak contribution from haze, in good agreement with the preliminary reduction of these data presented in Sing et al. WASP-39b is predicted to have a pressure-temperature profile comparable to that of HD 189733b and WASP-6b, making it one of the coolest transiting gas giants observed in our HST STIS survey. Despite this similarity, WASP-39b appears to be largely cloud-free, while the transmission spectra of HD 189733b and WASP-6b both indicate the presence of high altitude clouds or hazes. These observations further emphasize the surprising diversity of cloudy and cloud-free gas giant planets in short-period orbits and the corresponding challenges associated with developing predictive cloud models for these atmospheres.

  15. Merging high resolution geophysical and geochemical surveys to reduce exploration risk at glass buttes, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Patrick [Ormat Nevada, Inc., Reno, NV (United States); Fercho, Steven [Ormat Nevada, Inc., Reno, NV (United States); Perkin, Doug [Ormat Nevada, Inc., Reno, NV (United States); Martini, Brigette [Corescan Inc., Ascot (Australia); Boshmann, Darrick [Oregon State Univ., Corvallis, OR (United States)

    2015-06-01

    The engineering and studies phase of the Glass Buttes project was aimed at reducing risk during the early stages of geothermal project development. The project’s inclusion of high resolution geophysical and geochemical surveys allowed Ormat to evaluate the value of these surveys both independently and in combination to quantify the most valuable course of action for exploration in an area where structure, permeability, and temperature are the most pressing questions. The sizes of the thermal anomalies at Glass Buttes are unusually large. Over the course of Phase I Ormat acquired high resolution LIDAR data to accurately map fault manifestations at the surface and collected detailed gravity and aeromagnetic surveys to map subsurface structural features. In addition, Ormat collected airborne hyperspectral data to assist with mapping the rock petrology and mineral alteration assemblages along Glass Buttes faults and magnetotelluric (MT) survey to try to better constrain the structures at depth. Direct and indirect identification of alteration assemblages reveal not only the geochemical character and temperature of the causative hydrothermal fluids but can also constrain areas of upflow along specific fault segments. All five datasets were merged along with subsurface lithologies and temperatures to predict the most likely locations for high permeability and hot fluids. The Glass Buttes temperature anomalies include 2 areas, totaling 60 km2 (23 mi2) of measured temperature gradients over 165° C/km (10° F/100ft). The Midnight Point temperature anomaly includes the Strat-1 well with 90°C (194 °F) at 603 m (1981 ft) with a 164 °C/km (10°F/100ft) temperature gradient at bottom hole and the GB-18 well with 71°C (160 °F) at 396 m (1300 ft) with a 182°C/km (11°F/100ft) gradient. The primary area of alteration and elevated temperature occurs near major fault intersections associated with Brothers Fault Zone and Basin and Range systems. Evidence for faulting is

  16. THE HERSCHEL AND IRAM CHESS SPECTRAL SURVEYS OF THE PROTOSTELLAR SHOCK L1157-B1: FOSSIL DEUTERATION

    Energy Technology Data Exchange (ETDEWEB)

    Codella, C.; Fontani, F.; Vasta, M. [INAF, Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze (Italy); Ceccarelli, C.; Lefloch, B.; Kahane, C.; Taquet, V.; Wiesenfeld, L. [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041 (France); Busquet, G. [INAF - Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere 100, I-00133, Roma (Italy); Caselli, P. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Lis, D. [California Institute of Technology, Cahill Center for Astronomy and Astrophysics 301-17, Pasadena, CA 91125 (United States); Viti, S., E-mail: codella@rcetri.astro.it [Department of Physics and Astronomy, University College London, London (United Kingdom)

    2012-09-20

    We present the first study of deuteration toward the protostellar shock L1157-B1, based on spectral surveys performed with the Herschel-HIFI and IRAM 30 m telescopes. The L1157 outflow is driven by a low-mass Class 0 protostar and is considered the prototype of the so-called chemically active outflows. The young (2000 yr), bright blueshifted bow shock, B1, is an ideal laboratory for studying the gas chemically enriched by the release of dust mantles due to the passage of a shock. A total of 12 emission lines (up to E{sub u} = 63 K) of CH{sub 2}DOH, HDCO, and DCN are detected. In addition, two lines of NH{sub 2}D and HDO are tentatively reported. To estimate the deuteration, we also extracted from our spectral survey emission lines of non-deuterated isotopologues ({sup 13}CH{sub 3}OH, H{sub 2} {sup 13}CO, H{sup 13}CN, H{sub 2} {sup 13}CO, and NH{sub 3}). We infer higher deuteration fractions for CH{sub 3}OH (D/H = 0.2-2 Multiplication-Sign 10{sup -2}) and H{sub 2}CO (5-8 Multiplication-Sign 10{sup -3}) than for H{sub 2}O (0.4-2 Multiplication-Sign 10{sup -3}), HCN ({approx}10{sup -3}), and ammonia ({<=}3 Multiplication-Sign 10{sup -2}). The measurement of deuteration of water, formaldehyde, and methanol in L1157-B1 provides a fossil record of the gas before it was shocked by the jet driven by the protostar. A comparison with gas-grain models indicates that the gas passed through a low-density ({<=}10{sup 3} cm{sup -3}) phase, during which the bulk of water ices formed, followed by a phase of increasing density, up to 3 Multiplication-Sign 10{sup 4} cm{sup -3}, during which formaldehyde and methanol ices formed.

  17. Construction of a High Temporal-spectral Resolution Spectrometer for Detection of Fast Transients from Observations of the Sun at 1.4 GHz.

    Science.gov (United States)

    Casillas-Perez, G. A.; Jeyakumar, S.; Perez-Enriquez, R.

    2014-12-01

    Transients explosive events with time durations from nanoseconds to several hours, are observed in the Sun at high energy bands such as gamma ray and xray. In the radio band, several types of radio bursts are commonly detected from the ground. A few observations of the Sun in the past have also detected a new class of fast transients which are known to have short-live electromagnetic emissions with durations less than 100 ms. The mechanisms that produce such fast transiets remain unclear. Observations of such fast transients over a wide bandwidth is necessary to uderstand the underlying physical process that produce such fast transients. Due to their very large flux densities, fast radio transients can be observed at high time resolution using small antennas in combination with digital signal processing techniques. In this work we report the progress of an spectrometer that is currently in construction at the Observatorio de la Luz of the Universidad de Guanajuato. The instrument which will have the purpose of detecting solar fast radio transients, involves the use of digital devices such as FPGA and ADC cards, in addition with a receiver with high temporal-spectral resolution centered at 1.4 GHz and a pair of 2.3 m satellite dish.

  18. Real-time generation of images with pixel-by-pixel spectra for a coded aperture imager with high spectral resolution

    International Nuclear Information System (INIS)

    Ziock, K.P.; Burks, M.T.; Craig, W.; Fabris, L.; Hull, E.L.; Madden, N.W.

    2003-01-01

    The capabilities of a coded aperture imager are significantly enhanced when a detector with excellent energy resolution is used. We are constructing such an imager with a 1.1 cm thick, crossed-strip, planar detector which has 38 strips of 2 mm pitch in each dimension followed by a large coaxial detector. Full value from this system is obtained only when the images are 'fully deconvolved' meaning that the energy spectrum is available from each pixel in the image. The large number of energy bins associated with the spectral resolution of the detector, and the fixed pixel size, present significant computational challenges in generating an image in a timely manner at the conclusion of a data acquisition. The long computation times currently preclude the generation of intermediate images during the acquisition itself. We have solved this problem by building the images on-line as each event comes in using pre-imaged arrays of the system response. The generation of these arrays and the use of fractional mask-to-detector pixel sampling is discussed

  19. High-resolution SMA imaging of bright submillimetre sources from the SCUBA-2 Cosmology Legacy Survey

    Science.gov (United States)

    Hill, Ryley; Chapman, Scott C.; Scott, Douglas; Petitpas, Glen; Smail, Ian; Chapin, Edward L.; Gurwell, Mark A.; Perry, Ryan; Blain, Andrew W.; Bremer, Malcolm N.; Chen, Chian-Chou; Dunlop, James S.; Farrah, Duncan; Fazio, Giovanni G.; Geach, James E.; Howson, Paul; Ivison, R. J.; Lacaille, Kevin; Michałowski, Michał J.; Simpson, James M.; Swinbank, A. M.; van der Werf, Paul P.; Wilner, David J.

    2018-06-01

    We have used the Submillimeter Array (SMA) at 860 μm to observe the brightest sources in the Submillimeter Common User Bolometer Array-2 (SCUBA-2) Cosmology Legacy Survey (S2CLS). The goal of this survey is to exploit the large field of the S2CLS along with the resolution and sensitivity of the SMA to construct a large sample of these rare sources and to study their statistical properties. We have targeted 70 of the brightest single-dish SCUBA-2 850 μm sources down to S850 ≈ 8 mJy, achieving an average synthesized beam of 2.4 arcsec and an average rms of σ860 = 1.5 mJy beam-1 in our primary beam-corrected maps. We searched our SMA maps for 4σ peaks, corresponding to S860 ≳ 6 mJy sources, and detected 62, galaxies, including three pairs. We include in our study 35 archival observations, bringing our sample size to 105 bright single-dish submillimetre sources with interferometric follow-up. We compute the cumulative and differential number counts, finding them to overlap with previous single-dish survey number counts within the uncertainties, although our cumulative number count is systematically lower than the parent S2CLS cumulative number count by 14 ± 6 per cent between 11 and 15 mJy. We estimate the probability that a ≳10 mJy single-dish submillimetre source resolves into two or more galaxies with similar flux densities to be less than 15 per cent. Assuming the remaining 85 per cent of the targets are ultraluminous starburst galaxies between z = 2 and 3, we find a likely volume density of ≳400 M⊙ yr-1 sources to be {˜ } 3^{+0.7}_{-0.6} {× } 10^{-7} Mpc-3. We show that the descendants of these galaxies could be ≳4 × 1011 M⊙ local quiescent galaxies, and that about 10 per cent of their total stellar mass would have formed during these short bursts of star formation.

  20. Spectral Difference in the Image Domain for Large Neighborhoods, a GEOBIA Pre-Processing Step for High Resolution Imagery

    Directory of Open Access Journals (Sweden)

    Roeland de Kok

    2012-08-01

    Full Text Available Contrast plays an important role in the visual interpretation of imagery. To mimic visual interpretation and using contrast in a Geographic Object Based Image Analysis (GEOBIA environment, it is useful to consider an analysis for single pixel objects. This should be done before applying homogeneity criteria in the aggregation of pixels for the construction of meaningful image objects. The habit or “best practice” to start GEOBIA with pixel aggregation into homogeneous objects should come with the awareness that feature attributes for single pixels are at risk of becoming less accessible for further analysis. Single pixel contrast with image convolution on close neighborhoods is a standard technique, also applied in edge detection. This study elaborates on the analysis of close as well as much larger neighborhoods inside the GEOBIA domain. The applied calculations are limited to the first segmentation step for single pixel objects in order to produce additional feature attributes for objects of interest to be generated in further aggregation processes. The equation presented functions at a level that is considered an intermediary product in the sequential processing of imagery. The procedure requires intensive processor and memory capacity. The resulting feature attributes highlight not only contrasting pixels (edges but also contrasting areas of local pixel groups. The suggested approach can be extended and becomes useful in classifying artificial areas at national scales using high resolution satellite mosaics.

  1. Physical and chemical differentiation of the luminous star-forming region W49A. Results from the JCMT Spectral Legacy Survey

    Science.gov (United States)

    Nagy, Z.; van der Tak, F. F. S.; Fuller, G. A.; Plume, R.

    2015-05-01

    Context. The massive and luminous star-forming region W49A is a well-known Galactic candidate to probe the physical conditions and chemistry similar to those expected in external starburst galaxies. Aims: We aim to probe the physical and chemical structure of W49A on a spatial scale of ~0.8 pc based on the JCMT Spectral Legacy Survey, which covers the frequency range between 330 and 373 GHz. Methods: The wide 2 × 2 arcmin field and the high spectral resolution of the HARP instrument on JCMT provides information on the spatial structure and kinematics of the cloud traced by the observed molecular lines. For species where multiple transitions are available, we estimate excitation temperatures and column densities using a population diagram method that takes beam dilution and optical depth corrections into account. Results: We detected 255 transitions corresponding to 63 species in the 330-373 GHz range at the center position of W49A. Excitation conditions can be probed for 14 molecules, including the complex organic molecules CH3CCH, CH3CN, and CH3OH. The chemical composition suggests the importance of shock, photon-dominated region (PDR), and hot core chemistry. Many molecular lines show a significant spatial extent across the maps including CO and its isotopologues, high density tracers (e.g., HCN, HNC, CS, HCO+), and tracers of UV irradiation (e.g., CN and C2H). The spatially extended species reveal a complex velocity-structure of W49A with possible infall and outflow motions. Large variations are seen between the subregions with mostly blue-shifted emission toward the eastern tail, mostly red-shifted emission toward the northern clump, and emission peaking around the expected source velocity toward the southwest clump. Conclusions: A comparison of column density ratios of characteristic species observed toward W49A to Galactic PDRs suggests that while the chemistry toward the W49A center is driven by a combination of UV irradiation and shocks, UV irradiation

  2. AN UNBIASED SPECTRAL LINE SURVEY TOWARD R CrA IRS7B IN THE 345 GHz WINDOW WITH ASTE

    International Nuclear Information System (INIS)

    Watanabe, Yoshimasa; Sakai, Nami; Yamamoto, Satoshi; Lindberg, Johan E.; Bisschop, Suzanne E.; Jørgensen, Jes K.

    2012-01-01

    We have conducted a spectral line survey in the 332-364 GHz region with the Atacama Submillimeter Telescope Experiment 10 m telescope toward R CrA IRS7B, a low-mass protostar in the Class 0 or Class 0/I transitional stage. We have also performed some supplementary observations in the 450 GHz band. In total, 16 molecular species are identified in the 332-364 GHz region. Strong emission lines of CN and CCH are observed, whereas complex organic molecules and long carbon-chain molecules, which are characteristics of hot corino and warm carbon-chain chemistry (WCCC) source, respectively, are not detected. The rotation temperature of CH 3 OH is evaluated to be 31 K, which is significantly lower than that reported for the prototypical hot corino IRAS 16293-2422 (∼85 K). The deuterium fractionation ratios for CCH and H 2 CO are obtained to be 0.038 and 0.050, respectively, which are much lower than those in the hot corino. These results suggest a weak hot corino activity in R CrA IRS7B. On the other hand, the carbon-chain related molecules, CCH and c-C 3 H 2 , are found to be abundant. However, this source cannot be classified as a WCCC source, since long carbon-chain molecules are not detected. If WCCC and hot corino chemistry represent the two extremes in chemical compositions of low-mass Class 0 sources, R CrA IRS7B would be a source with a mixture of these two chemical characteristics. The UV radiation from the nearby Herbig Ae star R CrA may also affect the chemical composition. The present line survey demonstrates further chemical diversity in low-mass star-forming regions.

  3. Spectral line survey toward the spiral arm of M51 in the 3 and 2 mm bands

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Yoshimasa; Sakai, Nami; Yamamoto, Satoshi [Department of Physics, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Sorai, Kazuo, E-mail: nabe@taurus.phys.s.u-tokyo.ac.jp [Department of Physics/Department of Cosmoscience, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810 (Japan)

    2014-06-10

    We have conducted a spectral line survey in the 3 and 2 mm bands toward two positions in a spiral arm of M51 (NGC 5194) with the Institut de Radioastronomie Millimétrique 30 m telescope. In this survey, we have identified 13 molecular species, including CN, CCH, N{sub 2}H{sup +}, HNCO, and CH{sub 3}OH. Furthermore, six isotopologues of the major species have been detected. On the other hand, SiO, HC{sub 3}N, CH{sub 3}CN, and deuterated species such as DCN and DCO{sup +} were not detected. The deuterium fractionation ratios are evaluated to be less than 0.8% and 1.2% for DCN/HCN and DCO{sup +}/HCO{sup +}, respectively. By comparing the results of the two positions with different star formation activities, we have found that the observed chemical compositions do not strongly depend on star formation activities. They seem to reflect a chemical composition averaged over the 1 kpc scale region including many giant molecular clouds. Among the detected molecules CN, CCH, and CH{sub 3}OH are found to be abundant. High abundances of CN and CCH are consistent with the above picture of a widespread distribution of molecules because they can be produced by photodissociation. On the other hand, it seems likely that CH{sub 3}OH is liberated in the gas phase by shocks associated with large-scale phenomena such as cloud-cloud collisions and/or by nonthermal desorption processes such as photoevaporation due to cosmic-ray-induced UV photons. The present result demonstrates a characteristic chemical composition of a giant molecular cloud complex in the spiral arm, which can be used as a standard reference for studying chemistry in active galactic nuclei and starbursts.

  4. Remote sensing of potential lunar resources. 2: High spatial resolution mapping of spectral reflectance ratios and implications for nearside mare TiO2 content`

    Science.gov (United States)

    Melendrez, David E.; Johnson, Jeffrey R.; Larson, Stephen M.; Singer, Robert B.

    1994-01-01

    High spatial resolution maps illustrating variations in spectral reflectance 400/560 nm ratio values have been generated for the following mare regions: (1) the border between southern Mare Serenitatis and northern Mare Tranquillitatis (including the MS-2 standard area and Apollo 17 landing site), (2) central Mare Tranquillitatis, (3) Oceanus Procellarum near Seleucus, and (4) southern Oceanus Procellarum and Flamsteed. We have also obtained 320-1000 nm reflectance spectra of several sites relative to MS-2 to facilitate scaling of the images and provide additional information on surface composition. Inferred TiO2 abundances for these mare regions have been determined using an empirical calibration which relates the weight percent TiO2 in mature mare regolith to the observed 400/560 nm ratio. Mare areas with high TiO2 abundances are probably rich in ilmenite (FeTiO3) a potential lunar resource. The highest potential TiO2 concentrations we have identified in the nearside maria occur in central Mare Tranquillitatis. Inferred TiO2 contents for these areas are greater than 9 wt% and are spatially consistent with the highest-TiO2 regions mapped previously at lower spatial resolution. We note that the morphology of surface units with high 400/560 nm ratio values increases in complexity at higher spatial resolutions. Comparisons have been made with previously published geologic maps, Lunar Orbiter IV, and ground-based images, and some possible morphologic correlatins have been found between our mapped 400/560 nm ratio values and volcanic landforms such as lava flows, mare domes, and collapse pits.

  5. A multi-method high-resolution geophysical survey in the Machado de Castro museum, central Portugal

    International Nuclear Information System (INIS)

    Grangeia, Carlos; Matias, Manuel; Hermozilha, Hélder; Figueiredo, Fernando; Carvalho, Pedro; Silva, Ricardo

    2011-01-01

    Restoration of historical buildings is a delicate operation as they are often built over more ancient and important structures. The Machado de Castro Museum, Coimbra, Central Portugal, has suffered several interventions in historical times and lies over the ancient Roman forum of Coimbra. This building went through a restoration project. These works were preceded by an extensive geophysical survey that aimed at investigating subsurface stratigraphy, including archeological remains, and the internal structure of the actual walls. Owing to the needs of the project, geophysical data interpretation required not only integration but also high resolution. The study consisted of data acquisition over perpendicular planes and different levels that required detailed survey planning and integration of data from different locations that complement images of the surveyed area. Therefore a multi-method, resistivity imaging and a 3D ground probing radar (GPR), high-resolution geophysical survey was done inside the museum. Herein, radargrams are compared with the revealed stratigraphy so that signatures are interpreted, characterized and assigned to archeological structures. Although resistivity and GPR have different resolution capabilities, their data are overlapped and compared, bearing in mind the specific characteristics of this survey. It was also possible to unravel the inner structure of the actual walls, to establish connections between walls, foundations and to find older remains with the combined use and spatial integration of the GPR and resistivity imaging data

  6. Adding the s-Process Element Cerium to the APOGEE Survey: Identification and Characterization of Ce II Lines in the H-band Spectral Window

    Science.gov (United States)

    Cunha, Katia; Smith, Verne V.; Hasselquist, Sten; Souto, Diogo; Shetrone, Matthew D.; Allende Prieto, Carlos; Bizyaev, Dmitry; Frinchaboy, Peter; García-Hernández, D. Anibal; Holtzman, Jon; Johnson, Jennifer A.; Jőnsson, Henrik; Majewski, Steven R.; Mészáros, Szabolcs; Nidever, David; Pinsonneault, Mark; Schiavon, Ricardo P.; Sobeck, Jennifer; Skrutskie, Michael F.; Zamora, Olga; Zasowski, Gail; Fernández-Trincado, J. G.

    2017-08-01

    Nine Ce II lines have been identified and characterized within the spectral window observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey (between λ1.51 and 1.69 μm). At solar metallicities, cerium is an element that is produced predominantly as a result of the slow capture of neutrons (the s-process) during asymptotic giant branch stellar evolution. The Ce II lines were identified using a combination of a high-resolution (R=λ /δ λ ={{100,000}}) Fourier Transform Spectrometer (FTS) spectrum of α Boo and an APOGEE spectrum (R = 22,400) of a metal-poor, but s-process enriched, red giant (2M16011638-1201525). Laboratory oscillator strengths are not available for these lines. Astrophysical gf-values were derived using α Boo as a standard star, with the absolute cerium abundance in α Boo set by using optical Ce II lines that have precise published laboratory gf-values. The near-infrared Ce II lines identified here are also analyzed, as consistency checks, in a small number of bright red giants using archival FTS spectra, as well as a small sample of APOGEE red giants, including two members of the open cluster NGC 6819, two field stars, and seven metal-poor N- and Al-rich stars. The conclusion is that this set of Ce II lines can be detected and analyzed in a large fraction of the APOGEE red giant sample and will be useful for probing chemical evolution of the s-process products in various populations of the Milky Way.

  7. THE SPITZER INFRARED NEARBY GALAXIES SURVEY: A HIGH-RESOLUTION SPECTROSCOPY ANTHOLOGY

    International Nuclear Information System (INIS)

    Dale, D. A.; Schlawin, E. A.; Cohen, S. A.; Johnson, L. C.; Staudaher, S.; Smith, J. D. T.; Armus, L.; Helou, G.; Jarrett, T. H.; Murphy, E. J.; Sheth, K.; Buckalew, B. A.; Moustakas, J.; Roussel, H.; Bot, C.; Calzetti, D.; Engelbracht, C. W.; Gordon, K. D.; Hollenbach, D. J.; Kennicutt, R. C.

    2009-01-01

    High-resolution mid-infrared spectra are presented for 155 nuclear and extranuclear regions from the Spitzer Infrared Nearby Galaxies Survey (SINGS). The fluxes for nine atomic forbidden and three molecular hydrogen mid-infrared emission lines are also provided, along with upper limits in key lines for infrared-faint targets. The SINGS sample shows a wide range in the ratio of [S III] 18.71 μm/[S III] 33.48 μm, but the average ratio of the ensemble indicates a typical interstellar electron density of 300-400 cm -3 on ∼23'' x 15'' scales and 500-600 cm -3 using ∼11'' x 9'' apertures, independent of whether the region probed is a star-forming nuclear, a star-forming extranuclear, or an active galactic nuclei (AGN) environment. Evidence is provided that variations in gas-phase metallicity play an important role in driving variations in radiation field hardness, as indicated by [Ne III] 15.56 μm/[Ne II] 12.81 μm, for regions powered by star formation. Conversely, the radiation hardness for galaxy nuclei powered by accretion around a massive black hole is independent of metal abundance. Furthermore, for metal-rich environments AGN are distinguishable from star-forming regions by significantly larger [Ne III] 15.56 μm/[Ne II] 12.81 μm ratios. Finally, [Fe II] 25.99 μm/[Ne II] 12.81 μm versus [Si II] 34.82 μm/[S III] 33.48 μm also provides an empirical method for discerning AGN from normal star-forming sources. However, similar to [Ne III] 15.56 μm/[Ne II] 12.81 μm, these mid-infrared line ratios lose their AGN/star-formation diagnostic powers for very low metallicity star-forming systems with hard radiation fields.

  8. In vivo visualization of photoreceptor layer and lipofuscin accumulation in Stargardt’s disease and fundus flavimaculatus by high resolution spectral-domain optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Giuseppe Querques

    2009-12-01

    Full Text Available Giuseppe Querques, Rosy Prato, Gabriel Coscas, Gisèle Soubrane, Eric H SouiedDepartment of Ophthalmology, Hopital Intercommunal de Creteil, University Paris XII, FranceIntroduction: To assess photoreceptor (PR layer morphology in patients with Stargardt’s disease (STGD and fundus flavimaculatus (FFM using high resolution spectral domain optical coherence tomography (HD-OCT; OCT 4000 Cirrus, Humphrey-Zeiss, San Leandro, CA.Methods: This was a prospective observational case series. Sixteen consecutive patients with STGD and FFM underwent a complete ophthalmologic examination. Optical coherence tomography examination was performed with HD-OCT, a high-speed (27,000 axial scans per second OCT system using spectral/Fourier domain detection, with an axial image resolution of 5 µm.Results: A total of 31 eyes were included in the study. Transverse loss of the PR layer in the foveal region was shown by HD-OCT. Twenty eyes with clinically evident central atrophy had a disruption of either the Verhoeff‘s membrane (VM or the layer corresponding to the interface of inner segment (IS and outer segment (OS of PR in the foveal region. Among these eyes, 12/20 eyes had a loss of the PR layer (loss of both VM and IS-OS interface in the foveal region. Eleven eyes (11/31 without clinically evident central atrophy had an intact interface of IS and OS of PR centrally. Moreover, we observed hyperreflective deposits: type 1 lesions located within the retinal pigment epithelium (RPE layer and at the level of the outer segments of PR, and type 2 lesions located at the level of the outer nuclear layer and clearly separated from the RPE layer. Type 1 lesions alone were associated with absence of loss of the PR layer in the foveal region in all eyes; type 2 lesions were always associated with presence of type 1 lesions, and often (8/12 eyes associated with loss of the PR layer within the foveal region. Mean best-corrected visual acuity (BCVA was significantly

  9. Assessment of the CALIPSO Lidar 532 nm attenuated backscatter calibration using the NASA LaRC airborne High Spectral Resolution Lidar

    Directory of Open Access Journals (Sweden)

    R. R. Rogers

    2011-02-01

    Full Text Available The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO spacecraft has provided global, high-resolution vertical profiles of aerosols and clouds since it became operational on 13 June 2006. On 14 June 2006, the NASA Langley Research Center (LaRC High Spectral Resolution Lidar (HSRL was deployed aboard the NASA Langley B-200 aircraft for the first of a series of 86 underflights of the CALIPSO satellite to provide validation measurements for the CALIOP data products. To better assess the range of conditions under which CALIOP data products are produced, these validation flights were conducted under both daytime and nighttime lighting conditions, in multiple seasons, and over a large range of latitudes and aerosol and cloud conditions. This paper presents a quantitative assessment of the CALIOP 532 nm calibration (through the 532 nm total attenuated backscatter using internally calibrated airborne HSRL underflight data and is the most extensive study of CALIOP 532 nm calibration. Results show that HSRL and CALIOP 532 nm total attenuated backscatter agree on average within 2.7% ± 2.1% (CALIOP lower at night and within 2.9% ± 3.9% (CALIOP lower during the day, demonstrating the accuracy of the CALIOP 532 nm calibration algorithms. Additionally, comparisons with HSRL show consistency of the CALIOP calibration before and after the laser switch in 2009 as well as improvements in the daytime version 3.01 calibration scheme compared with the version 2 calibration scheme. Potential biases and uncertainties in the methodology relevant to validating satellite lidar measurements with an airborne lidar system are discussed and found to be less than 4.5% ± 3.2% for this validation effort with HSRL. Results from this study are also compared with prior assessments of the CALIOP 532 nm attenuated backscatter calibration.

  10. Construction and first atmospheric observations of a high spectral resolution lidar system in Argentina in the frame of a trinational Japanese-Argentinean-Chilean collaboration

    Science.gov (United States)

    Papandrea, S.; Jin, Y.; Ristori, P.; Otero, L.; Nishizawa, T.; Mizuno, A.; Sugimoto, N.; Quel, E.

    2016-05-01

    Atmospheric monitoring stations are being developed in Argentina. The most important targets are volcanic ashes, desert aerosols in particular Patagonian dust and biomass burning aerosols. Six stations deployed in the Patagonian Region and Buenos Aires have lidar systems, sun photometers integrated to the AERONET/NASA monitoring network, in situ optical particle analyzers, four solar radiation sensors (pyranometer, UVA, UVB and GUV), and meteorological equipment. The stations are in the main international airports of the Regions (San Carlos de Bariloche, Comodoro Rivadavia, Neuquén, Rio Gallegos) and in Buenos Aires (Aeroparque Jorge Newbery and at CEILAP/CITEDEF). CEILAP and the National Institute of Environmental Studies (NIES) at Tsukuba, Japan developed the first iodine cell-based high spectral resolution lidar (HSRL) in Argentina to add in the lidar network. We upgraded the standard CEILAP multi-wavelength Raman lidar adding the laser frequency tuning system and the 532 iodine-filtered channel at the reception to built the HSRL. HSRL will provide daytime and nighttime direct observation of the aerosol and cloud optical properties (backscatter and extinction) without the pre-assumption of the lidar ratio. This work shows the design and construction of the first Argentinean HSRL. We also show the first lidar observations done in the country with this kind of lidar.

  11. High Spectral Resolution Lidar and MPLNET Micro Pulse Lidar Aerosol Optical Property Retrieval Intercomparison During the 2012 7-SEAS Field Campaign at Singapore

    Science.gov (United States)

    Lolli, Simone; Welton, Ellsworth J.; Campbell, James R.; Eloranta, Edwin; Holben, Brent N.; Chew, Boon Ning; Salinas, Santo V.

    2014-01-01

    From August 2012 to February 2013 a High Resolution Spectral Lidar (HSRL; 532 nm) was deployed at that National University of Singapore near a NASA Micro Pulse Lidar NETwork (MPLNET; 527 nm) site. A primary objective of the MPLNET lidar project is the production and dissemination of reliable Level 1 measurements and Level 2 retrieval products. This paper characterizes and quantifies error in Level 2 aerosol optical property retrievals conducted through inversion techniques that derive backscattering and extinction coefficients from MPLNET elastic single-wavelength datasets. MPLNET Level 2 retrievals for aerosol optical depth and extinction/backscatter coefficient profiles are compared with corresponding HSRL datasets, for which the instrument collects direct measurements of each using a unique optical configuration that segregates aerosol and cloud backscattered signal from molecular signal. The intercomparison is performed, and error matrices reported, for lower (0-5km) and the upper (>5km) troposphere, respectively, to distinguish uncertainties observed within and above the MPLNET instrument optical overlap regime.

  12. Repeated 1-cm Resolution Topographic and 2.5-mm Resolution Photomosiac Surveys of Benthic Communities and Fine Scale Bedforms in Monterey Canyon

    Science.gov (United States)

    Caress, D. W.; Hobson, B.; Thomas, H. J.; Henthorn, R.; Martin, E. J.; Bird, L.; Risi, M.; Troni, G.; Paull, C. K.; Rock, S.; Padial, J. A.; Hammond, M. M.

    2014-12-01

    The Monterey Bay Aquarium Research Institute has developed a low altitude, ROV-based seafloor mapping system that combines lidar laser ranging, multibeam sonar, and stereo photographic imagery. When operated at a 3-m altitude, this system maps seafloor topography with a 1-cm lateral resolution and simultaneously collects 2.5-mm resolution color photography. We have twice mapped an 80-m by 80-m area of a chemosynthetic clam community located at 2850-m depth in the Monterey Canyon axis. Both the topography and the photomosaics resolve changes in the clam community over a six-month interval. Many individual animals have moved, and tracks of those animals are visible in the lidar topography. No other changes in the seafloor at this site can be discerned. We have also performed single surveys of bedforms and scours at both 1850-m and 2850-m depths in Monterey Canyon. The highest resolution bathymetry data are collected using a 3DatDepth SL1 lidar laser scanner. This system has a 30° field of view and ranges continuously, achieving a 1 cm sounding spacing at a 3 m altitude and 0.3 m/s speed. Bathymetry data are also collected using a 400-kHz Reson 7125 multibeam sonar. This configuration produces 512 beams across a 135° wide swath; each beam has a 0.5° acrosstrack by 1.0° alongtrack angular width. At a 3-m altitude, the nadir beams have a 2.5 cm acrosstrack and 5 cm alongtrack footprint. Dual Prosilica GX1920 2.4 Mpixel color cameras provide color stereo photography of the seafloor. Illumination is provided by dual xenon strobes. The camera housings have been fitted with corrective optics achieving a 90° field of view with less than 1% distortion. At a 3-m altitude the raw image pixels have a 2.5 mm resolution. Position and attitude data are provided by a Kearfott SeaDevil Inertial Navigation System (INS) integrated with a 300 kHz Teledyne RD Instruments Doppler velocity log (DVL). A separate Paroscientific pressure sensor is mounted adjacent to the INS. The INS

  13. Adaptive Spectral Doppler Estimation

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jakobsson, Andreas; Jensen, Jørgen Arendt

    2009-01-01

    . The methods can also provide better quality of the estimated power spectral density (PSD) of the blood signal. Adaptive spectral estimation techniques are known to pro- vide good spectral resolution and contrast even when the ob- servation window is very short. The 2 adaptive techniques are tested......In this paper, 2 adaptive spectral estimation techniques are analyzed for spectral Doppler ultrasound. The purpose is to minimize the observation window needed to estimate the spectrogram to provide a better temporal resolution and gain more flexibility when designing the data acquisition sequence...... and compared with the averaged periodogram (Welch’s method). The blood power spectral capon (BPC) method is based on a standard minimum variance technique adapted to account for both averaging over slow-time and depth. The blood amplitude and phase estimation technique (BAPES) is based on finding a set...

  14. Ensonifying Change: Repeat Ultra-High-Resolution Surveys in Monterey Canyon before and after Passage of a Turbidity Current

    Science.gov (United States)

    Wolfson-Schwehr, M.; Paull, C. K.; Caress, D. W.; Carvajal, C.; Thomas, H. J.; Maier, K. L.; Parsons, D. R.; Simmons, S.

    2017-12-01

    Turbidity currents are one of the primary means of global sediment transport, yet our understanding of how they interact with the seafloor is hindered by the limited number of direct measurements. The Coordinated Canyon Experiment (CCE; October 2015 - April 2017) has made great strides in addressing this issue by providing direct measurements of turbidity currents and detailed observations of the resulting seafloor change in Monterey Canyon, offshore California. Here we focus on a section of the canyon at 1850-m water depth, where a Seafloor Instrument Node (SIN) recorded passage of three turbidity currents using a range of sensors, including three upward-looking acoustic Doppler current profilers. The fastest event at this site had a maximum velocity of 2.8 m/s, and dragged the 430-Kg SIN 26 m down-canyon. Repeat mapping surveys were conducted four times during the CCE, utilizing a prototype ultra-high-resolution mapping system mounted on the ROV Doc Ricketts. The survey platform hosts a 400-kHz Reson 7125 multibeam sonar, a 3DatDepth SL1 subsea LiDAR, two stereo color cameras, and a Kearfott SeaDevil INS. At a survey altitude of 2.5 m above the bed, the system provides remarkable 5-cm resolution multibeam bathymetry, 1-cm resolution LiDAR bathymetry, and 2-mm resolution photomosaics, and can cover a 100-m2 survey area. Surveys of the SIN site prior to and after the fastest event show areas of net deposition/erosion of 60 cm and 20 cm, respectively. Net deposition occurred in the topographic lows between bedforms, while erosion was focused on the bedform crests. At the end of the experiment, transects of sediment cores were taken by ROV within areas of net deposition. The cores show a variety of sedimentary facies, including muds, sands, gravel, and organic rich layers. Gravel layers have sharp erosive bases. The repeat surveys document the dynamic nature of flute-like scours as the flow events erode and deposit material along the canyon floor, as well as the

  15. Comparison of the large-scale radon risk map for southern Belgium with results of high resolution surveys

    International Nuclear Information System (INIS)

    Zhu, H.-C.; Charlet, J.M.; Poffijn, A.

    2000-01-01

    A large-scale radon survey consisting of long-term measurements in about 5200 singe-family houses in the southern part of Belgium was carried from 1995 to 1999. A radon risk map for the region was produced using geostatistical and GIS approaches. Some communes or villages situated within high risk areas were chosen for detailed surveys. A high resolution radon survey with about 330 measurements was performed in half part of the commune of Burg-Reuland. Comparison of radon maps on quite different scales shows that the general Rn risk map has similar pattern as the radon map for the detailed study area. Another detailed radon survey in the village of Hatrival, situated in a high radon area, found very high proportion of houses with elevated radon concentrations. The results of this detailed survey are comparable to the expectation for high risk areas on the large-scale radon risk map. The good correspondence between the findings of the general risk map and the analysis of the limited detailed surveys, suggests that the large-scale radon risk map is likely reliable. (author)

  16. Arrange and average algorithm for the retrieval of aerosol parameters from multiwavelength high-spectral-resolution lidar/Raman lidar data.

    Science.gov (United States)

    Chemyakin, Eduard; Müller, Detlef; Burton, Sharon; Kolgotin, Alexei; Hostetler, Chris; Ferrare, Richard

    2014-11-01

    We present the results of a feasibility study in which a simple, automated, and unsupervised algorithm, which we call the arrange and average algorithm, is used to infer microphysical parameters (complex refractive index, effective radius, total number, surface area, and volume concentrations) of atmospheric aerosol particles. The algorithm uses backscatter coefficients at 355, 532, and 1064 nm and extinction coefficients at 355 and 532 nm as input information. Testing of the algorithm is based on synthetic optical data that are computed from prescribed monomodal particle size distributions and complex refractive indices that describe spherical, primarily fine mode pollution particles. We tested the performance of the algorithm for the "3 backscatter (β)+2 extinction (α)" configuration of a multiwavelength aerosol high-spectral-resolution lidar (HSRL) or Raman lidar. We investigated the degree to which the microphysical results retrieved by this algorithm depends on the number of input backscatter and extinction coefficients. For example, we tested "3β+1α," "2β+1α," and "3β" lidar configurations. This arrange and average algorithm can be used in two ways. First, it can be applied for quick data processing of experimental data acquired with lidar. Fast automated retrievals of microphysical particle properties are needed in view of the enormous amount of data that can be acquired by the NASA Langley Research Center's airborne "3β+2α" High-Spectral-Resolution Lidar (HSRL-2). It would prove useful for the growing number of ground-based multiwavelength lidar networks, and it would provide an option for analyzing the vast amount of optical data acquired with a future spaceborne multiwavelength lidar. The second potential application is to improve the microphysical particle characterization with our existing inversion algorithm that uses Tikhonov's inversion with regularization. This advanced algorithm has recently undergone development to allow automated and

  17. Spatial and spectral resolution of carbonaceous material from hematite (α-Fe2O3) using multivariate curve resolution-alternating least squares (MCR-ALS) with Raman microspectroscopic mapping: implications for the search for life on Mars.

    Science.gov (United States)

    Smith, Joseph P; Smith, Frank C; Booksh, Karl S

    2017-08-21

    The search for evidence of extant or past life on Mars is a primary objective of both the upcoming Mars 2020 rover (NASA) and ExoMars 2020 rover (ESA/Roscosmos) missions. This search will involve the detection and identification of organic molecules and/or carbonaceous material within the Martian surface environment. For the first time on a mission to Mars, the scientific payload for each rover will include a Raman spectrometer, an instrument well-suited for this search. Hematite (α-Fe 2 O 3 ) is a widespread mineral on the Martian surface. The 2LO Raman band of hematite and the Raman D-band of carbonaceous material show spectral overlap, leading to the potential misidentification of hematite as carbonaceous material. Here we report the ability to spatially and spectrally differentiate carbonaceous material from hematite using multivariate curve resolution-alternating least squares (MCR-ALS) applied to Raman microspectroscopic mapping under both 532 nm and 785 nm excitation. For this study, a sample comprised of hematite, carbonaceous material, and substrate-adhesive epoxy in spatially distinct domains was constructed. Principal component analysis (PCA) reveals that both 532 nm and 785 nm excitation produce representative three-phase systems of hematite, carbonaceous material, and substrate-adhesive epoxy in the analyzed sample. MCR-ALS with Raman microspectroscopic mapping using both 532 nm and 785 nm excitation was able to resolve hematite, carbonaceous material, and substrate-adhesive epoxy by generating spatially-resolved chemical maps and corresponding Raman spectra of these spatially distinct chemical species. Moreover, MCR-ALS applied to the combinatorial data sets of 532 nm and 785 nm excitation, which contain hematite and carbonaceous material within the same locations, was able to resolve hematite, carbonaceous material, and substrate-adhesive epoxy. Using multivariate analysis with Raman microspectroscopic mapping, 785 nm excitation more effectively

  18. Simultaneous polarimeter retrievals of microphysical aerosol and ocean color parameters from the "MAPP" algorithm with comparison to high-spectral-resolution lidar aerosol and ocean products.

    Science.gov (United States)

    Stamnes, S; Hostetler, C; Ferrare, R; Burton, S; Liu, X; Hair, J; Hu, Y; Wasilewski, A; Martin, W; van Diedenhoven, B; Chowdhary, J; Cetinić, I; Berg, L K; Stamnes, K; Cairns, B

    2018-04-01

    We present an optimal-estimation-based retrieval framework, the microphysical aerosol properties from polarimetry (MAPP) algorithm, designed for simultaneous retrieval of aerosol microphysical properties and ocean color bio-optical parameters using multi-angular total and polarized radiances. Polarimetric measurements from the airborne NASA Research Scanning Polarimeter (RSP) were inverted by MAPP to produce atmosphere and ocean products. The RSP MAPP results are compared with co-incident lidar measurements made by the NASA High-Spectral-Resolution Lidar HSRL-1 and HSRL-2 instruments. Comparisons are made of the aerosol optical depth (AOD) at 355 and 532 nm, lidar column-averaged measurements of the aerosol lidar ratio and Ångstrøm exponent, and lidar ocean measurements of the particulate hemispherical backscatter coefficient and the diffuse attenuation coefficient. The measurements were collected during the 2012 Two-Column Aerosol Project (TCAP) campaign and the 2014 Ship-Aircraft Bio-Optical Research (SABOR) campaign. For the SABOR campaign, 73% RSP MAPP retrievals fall within ±0.04 AOD at 532 nm as measured by HSRL-1, with an R value of 0.933 and root-mean-square deviation of 0.0372. For the TCAP campaign, 53% of RSP MAPP retrievals are within 0.04 AOD as measured by HSRL-2, with an R value of 0.927 and root-mean-square deviation of 0.0673. Comparisons with HSRL-2 AOD at 355 nm during TCAP result in an R value of 0.959 and a root-mean-square deviation of 0.0694. The RSP retrievals using the MAPP optimal estimation framework represent a key milestone on the path to a combined lidar + polarimeter retrieval using both HSRL and RSP measurements.

  19. An Impurity Emission Survey in the near UV and Visible Spectral Ranges of Electron Cyclotron Heated (ECH) Plasma in the TJ-II Stellarator

    International Nuclear Information System (INIS)

    McCarthy, K. J.; Zurro, B.; Baciero, A.

    2001-01-01

    We report on a near-ultraviolet and visible spectroscopic survey (220-600 nm) of electron cyclotron resonance (ECR) heated plasmas created in the TJ-II stellarator, with central electron temperatures up to 2 keV and central electron densities up to 1.7 x 10 ''19 m''-3. Approximately 1200 lines from thirteen elements have been identified. The purpose of the work is to identify the principal impurities and spectral lines present in TJ-II plasmas, as well as their possible origin to search for transitions from highly ionised ions. This work will act as a base for identifying suitable transitions for following the evolution of impurities under different operating regimens and multiplet systems for line polarisation studies. It is intended to use the database creates as a spectral line reference for comparing spectra under different operating and plasma heating regimes. (Author)

  20. Impacts of spectral nudging on the simulated surface air temperature in summer compared with the selection of shortwave radiation and land surface model physics parameterization in a high-resolution regional atmospheric model

    Science.gov (United States)

    Park, Jun; Hwang, Seung-On

    2017-11-01

    The impact of a spectral nudging technique for the dynamical downscaling of the summer surface air temperature in a high-resolution regional atmospheric model is assessed. The performance of this technique is measured by comparing 16 analysis-driven simulation sets of physical parameterization combinations of two shortwave radiation and four land surface model schemes of the model, which are known to be crucial for the simulation of the surface air temperature. It is found that the application of spectral nudging to the outermost domain has a greater impact on the regional climate than any combination of shortwave radiation and land surface model physics schemes. The optimal choice of two model physics parameterizations is helpful for obtaining more realistic spatiotemporal distributions of land surface variables such as the surface air temperature, precipitation, and surface fluxes. However, employing spectral nudging adds more value to the results; the improvement is greater than using sophisticated shortwave radiation and land surface model physical parameterizations. This result indicates that spectral nudging applied to the outermost domain provides a more accurate lateral boundary condition to the innermost domain when forced by analysis data by securing the consistency with large-scale forcing over a regional domain. This consequently indirectly helps two physical parameterizations to produce small-scale features closer to the observed values, leading to a better representation of the surface air temperature in a high-resolution downscaled climate.

  1. A novel spectral resolution and simultaneous determination of multicomponent mixture of Vitamins B1, B6, B12, Benfotiamine and Diclofenac in tablets and capsules by derivative and MCR-ALS

    Science.gov (United States)

    Hegazy, Maha A.; Abdelwahab, Nada S.; Fayed, Ahmed S.

    2015-04-01

    A novel method was developed for spectral resolution and further determination of five-component mixture including Vitamin B complex (B1, B6, B12 and Benfotiamine) along with the commonly co-formulated Diclofenac. The method is simple, sensitive, precise and could efficiently determine the five components by a complementary application of two different techniques. The first is univariate second derivative method that was successfully applied for determination of Vitamin B12. The second is Multivariate Curve Resolution using the Alternating Least Squares method (MCR-ALS) by which an efficient resolution and quantitation of the quaternary spectrally overlapped Vitamin B1, Vitamin B6, Benfotiamine and Diclofenac sodium were achieved. The effect of different constraints was studied and the correlation between the true spectra and the estimated spectral profiles were found to be 0.9998, 0.9983, 0.9993 and 0.9933 for B1, B6, Benfotiamine and Diclofenac, respectively. All components were successfully determined in tablets and capsules and the results were compared to HPLC methods and they were found to be statistically non-significant.

  2. Tsunami Rapid Assessment Using High Resolution Images and Field Surveys: the 2010 , Central Chile, and the 2011, Tohoku Tsunamis

    Science.gov (United States)

    Ramirez-Herrera, M.; Navarrete-Pacheco, J.; Lagos, M.; Arcas, D.

    2013-12-01

    Recent extreme tsunamis have shown their major socioeconomic impact and imprint in the coastal landscape. Extensive destruction, erosion, sediment transport and deposition resculpted coastal landscape within few minutes along hundreds of kilometers of the Central Chile, in 2010, and the Northeast coast of Japan, in 2011. In the central coast of Chile, we performed a post-tsunami survey a week after the tsunami due to access restrictions. Our observations focus on the inundation and geomorphic effects of the 2010 tsunami and included an air reconnaissance flight, analysis of pre- and post-event low fly air-photographs and Google Earth satellite images, together with ground reconnaissance and mapping in the field, including topographic transects, during a period of 13 days. Eyewitness accounts enabled us to confirm our observations on effects produced by the tsunami along ~ 500km along the coastline landscape in central Chile For the Tohoku case study, we assessed in a day tsunami inundation distances and runup heights using satellite data (very high resolution satellite images from the GeoEye1 satellite and from the DigitalGlobe worldview through the Google crisis response project, SRTM and ASTER GDEM) of the Tohoku region, Northeast Japan. Field survey data by Japanese, other international scientists and us validated our results. The rapid assessment of damage using high-resolution images has proven to be an excellent tool neccessary for effcient postsunami surveys as well as for rapid assessment of areas with access restrictions. All countries, in particular those with less access to technology and infrastructure, can benefit from the use of freely available satellite imagery and DEMs for an initial, pre-field survey, rapid estimate of inundated areas, distances and runup, tsunami effects in the coastal geomorphology and for assisting in hazard management and mitigation after a natural disaster. These data provide unprecedented opportunities for rapid assessment

  3. Analysis of Alabama Airborne Gravity at Three Altitudes: Expected Accuracy and Spatial Resolution from a Future Tibetan Airborne Gravity Survey

    Directory of Open Access Journals (Sweden)

    Chi-Hsun Huang

    2013-01-01

    Full Text Available In situ airborne gravity data at altitudes of 11, 6.3, and 1.7 km over a smooth area of Alabama are used to assess gravity accuracy and errors in upward and downward continuations. Analysis of the Alabama free-air anomaly gravity data at crossover points at the three altitudes suggests 1 - 2 mgal accuracy for the dataset. Gravity data at each altitude are then expanded into local 3D Fourier series, to prepare for continuation. This Fourier representation results in continuation errors at few-mgal level in Alabama, even in the extreme case of downward continuation from 11 km to sea level. The result in Alabama inspires an airborne gravity survey over the rough, inaccessible terrain of Tibet. Similar investigations as in Alabama are made in Tibet using EGM08-derived airborne gravity data at flight altitudes of 10, 5, and 0 km. Bouguer anomalies at the 10-km altitude preserve the major tectonic features of Tibet. Downward continuation errors increase with terrain roughness, but the survey can enhance local tectonic features. This study highlights the value of a future Tibetan airborne gravity survey and points out the expected gravity accuracy and spatial resolution from this survey.

  4. Heteronuclear Micro-Helmholtz Coil Facilitates µm-Range Spatial and Sub-Hz Spectral Resolution NMR of nL-Volume Samples on Customisable Microfluidic Chips.

    Directory of Open Access Journals (Sweden)

    Nils Spengler

    Full Text Available We present a completely revised generation of a modular micro-NMR detector, featuring an active sample volume of ∼ 100 nL, and an improvement of 87% in probe efficiency. The detector is capable of rapidly screening different samples using exchangeable, application-specific, MEMS-fabricated, microfluidic sample containers. In contrast to our previous design, the sample holder chips can be simply sealed with adhesive tape, with excellent adhesion due to the smooth surfaces surrounding the fluidic ports, and so withstand pressures of ∼2.5 bar, while simultaneously enabling high spectral resolution up to 0.62 Hz for H2O, due to its optimised geometry. We have additionally reworked the coil design and fabrication processes, replacing liquid photoresists by dry film stock, whose final thickness does not depend on accurate volume dispensing or precise levelling during curing. We further introduced mechanical alignment structures to avoid time-intensive optical alignment of the chip stacks during assembly, while we exchanged the laser-cut, PMMA spacers by diced glass spacers, which are not susceptible to melting during cutting. Doing so led to an overall simplification of the entire fabrication chain, while simultaneously increasing the yield, due to an improved uniformity of thickness of the individual layers, and in addition, due to more accurate vertical positioning of the wirebonded coils, now delimited by a post base plateau. We demonstrate the capability of the design by acquiring a 1H spectrum of ∼ 11 nmol sucrose dissolved in D2O, where we achieved a linewidth of 1.25 Hz for the TSP reference peak. Chemical shift imaging experiments were further recorded from voxel volumes of only ∼ 1.5 nL, which corresponded to amounts of just 1.5 nmol per voxel for a 1 M concentration. To extend the micro-detector to other nuclei of interest, we have implemented a trap circuit, enabling heteronuclear spectroscopy, demonstrated by two 1H/13C 2D HSQC

  5. Characteristics of Sounds Emitted During High-Resolution Marine Geophysical Surveys

    Science.gov (United States)

    2016-03-24

    Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law , no person shall be...marine transportation , oil and gas, marine mineral, and renewable energy projects. In particular, geophysical surveys support infrastructure siting...sand resource delineation, geomorphic characterization, environmental monitoring, archaeological resource identification, and mapping of shallow

  6. Comparison between sensors with different spectral resolutions, relative to the sumbandila satellite, for assessing site quality differences, in eucalyptus grandis plantations

    CSIR Research Space (South Africa)

    Main, R

    2008-10-01

    Full Text Available detailed spectral information. Narrowband sensors, with their many contiguous bands, have proved useful in discriminating between vegetation states, e.g. water stress and nutrient deficiencies. However, hyperspectral remote sensing has a number...

  7. Development of measurement apparatus for high resolution electrical surveys; Komitsudo denki tansa sokuteiki no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Moriuchi, H; Matsuda, Y; Shiokawa, Y [Sumiko Consultants Co. Ltd., Tokyo (Japan); Uchino, Y [Cosmic Co. Ltd., Tokyo (Japan)

    1996-05-01

    For the enforcement of the {rho}a-{rho}u survey method which is a type of high-density electrical survey, a multichannel resistivity measuring instrument has been developed. This instrument, in addition to the above, conducts resistivity tomography and various other kinds of high-density electrical survey. A potential produced by a low frequency rectangular current of 1Hz or lower outputted by the transmitter of this instrument is received and measured by the receiver connected to electrodes positioned at 100 or less locations. The receiver comprises a scanner that automatically switches from electrode to electrode, conditioner that processes signals, and controller. A transmitter of the standard design outputs a maximum voltage of 800V and maximum current of 2A, making a device suitable for probing 50 to several 100m-deep levels. The receiver is operated by a personal computer that the controller is provided with. The newly-developed apparatus succeeded in presenting high-precision images of the result of a {rho}a-{rho}u analysis for an apparent resistivity section and of the underground structure, verifying the high quality of the data collected by this apparatus. 10 refs., 5 figs., 1 tab.

  8. Tree survey and allometric models for tiger bush in northern Senegal and comparison with tree parameters derived from high resolution satellite data

    DEFF Research Database (Denmark)

    Rasmussen, Mads Olander; Goettsche, Frank-M.; Diop, Doudou

    2011-01-01

    A tree survey and an analysis of high resolution satellite data were performed to characterise the woody vegetation within a 10 x 10 km(2) area around a site located close to the town of Dahra in the semiarid northern part of Senegal. The surveyed parameters were tree species, height, tree crown...

  9. Mini-Sosie - a new concept in high-resolution seismic surveys

    Energy Technology Data Exchange (ETDEWEB)

    Wiles, C J

    1977-12-01

    Mini-Sosie is a new approach to high-resolution reflection seismics using a nondynamite source. The basic principles is to use an ordinary earth tamper to produce a long duration pseudo-random input pulse train. Returning signals from suitable geophone arrays are decoded in real time by crosscorrelation with the reference signal recorded from a source-sensor attached to the tamper plate. Relatively weak signals are stacked until sufficient amplitude is obtained; most noise is phased out during the decoding process while in-phase seismic events are added, resulting in good signal-to-noise ratios. The resulting output is the standard field seismogram. The source is relatively quiet and surface damage is insignificant thereby avoiding environmental restrictions. Mini-Sosie is especially useful for shallow investigation to one second (two-way time) and has a wide range of applications from shallow oil and gas exploration, coal, and hard mineral exploration to hydrology and engineering studies.

  10. The multiplicity of massive stars: A high angular resolution survey with the HST fine guidance sensor

    International Nuclear Information System (INIS)

    Aldoretta, E. J.; Gies, D. R.; Henry, T. J.; Jao, W.-C.; Norris, R. P.

    2015-01-01

    We present the results of an all-sky survey made with the Fine Guidance Sensor on the Hubble Space Telescope to search for angularly resolved binary systems among massive stars. The sample of 224 stars is comprised mainly of Galactic O- and B-type stars and luminous blue variables, plus a few luminous stars in the Large Magellanic Cloud. The FGS TRANS mode observations are sensitive to the detection of companions with an angular separation between 0.″01 and 1.″0 and brighter than △m=5. The FGS observations resolved 52 binary and 6 triple star systems and detected partially resolved binaries in 7 additional targets (43 of these are new detections). These numbers yield a companion detection frequency of 29% for the FGS survey. We also gathered literature results on the numbers of close spectroscopic binaries and wider astrometric binaries among the sample, and we present estimates of the frequency of multiple systems and the companion frequency for subsets of stars residing in clusters and associations, field stars, and runaway stars. These results confirm the high multiplicity fraction, especially among massive stars in clusters and associations. We show that the period distribution is approximately flat in increments of logP. We identify a number of systems of potential interest for long-term orbital determinations, and we note the importance of some of these companions for the interpretation of the radial velocities and light curves of close binaries that have third companions.

  11. Quantifying uncertainty in high-resolution remotely sensed topographic surveys for ephemeral gully channel monitoring

    Science.gov (United States)

    Wells, Robert R.; Momm, Henrique G.; Castillo, Carlos

    2017-07-01

    Spatio-temporal measurements of landform evolution provide the basis for process-based theory formulation and validation. Over time, field measurements of landforms have increased significantly worldwide, driven primarily by the availability of new surveying technologies. However, there is no standardized or coordinated effort within the scientific community to collect morphological data in a dependable and reproducible manner, specifically when performing long-term small-scale process investigation studies. Measurements of the same site using identical methods and equipment, but performed at different time periods, may lead to incorrect estimates of landform change as a result of three-dimensional registration errors. This work evaluated measurements of an ephemeral gully channel located on agricultural land using multiple independent survey techniques for locational accuracy and their applicability in generating information for model development and validation. Terrestrial and unmanned aerial vehicle photogrammetry platforms were compared to terrestrial lidar, defined herein as the reference dataset. Given the small scale of the measured landform, the alignment and ensemble equivalence between data sources was addressed through postprocessing. The utilization of ground control points was a prerequisite to three-dimensional registration between datasets and improved the confidence in the morphology information generated. None of the methods were without limitation; however, careful attention to project preplanning and data nature will ultimately guide the temporal efficacy and practicality of management decisions.

  12. A high-resolution spectropolarimetric survey of Herbig Ae/Be stars - II. Rotation

    Science.gov (United States)

    Alecian, E.; Wade, G. A.; Catala, C.; Grunhut, J. H.; Landstreet, J. D.; Böhm, T.; Folsom, C. P.; Marsden, S.

    2013-02-01

    We report the analysis of the rotational properties of our sample of Herbig Ae/Be (HAeBe) and related stars for which we have obtained high-resolution spectropolarimetric observations. Using the projected rotational velocities measured at the surface of the stars, we have calculated the angular momentum of the sample and plotted it as a function of age. We have then compared the angular momentum and the v sin i distributions of the magnetic to the non-magnetic HAeBe stars. Finally, we have predicted v sin i of the non-magnetic, non-binary (`normal') stars in our sample when they reach the zero-age main sequence (ZAMS), and compared them to various catalogues of v sin i of main-sequence stars. First, we observe that magnetic HAeBe stars are much slower rotators than normal stars, indicating that they have been more efficiently braked than the normal stars. In fact, the magnetic stars have already lost most of their angular momentum, despite their young ages (lower than 1 Myr for some of them). Secondly, our analysis suggests that the low-mass (1.5 5 M⊙) are losing angular momentum. We propose that winds, which are expected to be stronger in massive stars, are at the origin of this phenomenon.

  13. Headwater sediment dynamics in a debris flow catchment constrained by high-resolution topographic surveys

    Science.gov (United States)

    Loye, Alexandre; Jaboyedoff, Michel; Theule, Joshua Isaac; Liébault, Frédéric

    2016-06-01

    Debris flows have been recognized to be linked to the amounts of material temporarily stored in torrent channels. Hence, sediment supply and storage changes from low-order channels of the Manival catchment, a small tributary valley with an active torrent system located exclusively in sedimentary rocks of the Chartreuse Massif (French Alps), were surveyed periodically for 16 months using terrestrial laser scanning (TLS) to study the coupling between sediment dynamics and torrent responses in terms of debris flow events, which occurred twice during the monitoring period. Sediment transfer in the main torrent was monitored with cross-section surveys. Sediment budgets were generated seasonally using sequential TLS data differencing and morphological extrapolations. Debris production depends strongly on rockfall occurring during the winter-early spring season, following a power law distribution for volumes of rockfall events above 0.1 m3, while hillslope sediment reworking dominates debris recharge in spring and autumn, which shows effective hillslope-channel coupling. The occurrence of both debris flow events that occurred during the monitoring was linked to recharge from previous debris pulses coming from the hillside and from bedload transfer. Headwater debris sources display an ambiguous behaviour in sediment transfer: low geomorphic activity occurred in the production zone, despite rainstorms inducing debris flows in the torrent; still, a general reactivation of sediment transport in headwater channels was observed in autumn without new debris supply, suggesting that the stored debris was not exhausted. The seasonal cycle of sediment yield seems to depend not only on debris supply and runoff (flow capacity) but also on geomorphic conditions that destabilize remnant debris stocks. This study shows that monitoring the changes within a torrent's in-channel storage and its debris supply can improve knowledge on recharge thresholds leading to debris flow.

  14. High-Resolution Multibeam Sonar Survey and Interactive 3-D Exploration of the D-Day Wrecks off Normandy

    Science.gov (United States)

    Mayer, L. A.; Calder, B.; Schmidt, J. S.

    2003-12-01

    Historically, archaeological investigations use sidescan sonar and marine magnetometers as initial search tools. Targets are then examined through direct observation by divers, video, or photographs. Magnetometers can demonstrate the presence, absence, and relative susceptibility of ferrous objects but provide little indication of the nature of the target. Sidescan sonar can present a clear image of the overall nature of a target and its surrounding environment, but the sidescan image is often distorted and contains little information about the true 3-D shape of the object. Optical techniques allow precise identification of objects but suffer from very limited range, even in the best of situations. Modern high-resolution multibeam sonar offers an opportunity to cover a relatively large area from a safe distance above the target, while resolving the true three-dimensional (3-D) shape of the object with centimeter-level resolution. The combination of 3-D mapping and interactive 3-D visualization techniques provides a powerful new means to explore underwater artifacts. A clear demonstration of the applicability of high-resolution multibeam sonar to wreck and artifact investigations occurred when the Naval Historical Center (NHC), the Center for Coastal and Ocean Mapping (CCOM) at the University of New Hampshire, and Reson Inc., collaborated to explore the state of preservation and impact on the surrounding environment of a series of wrecks located off the coast of Normandy, France, adjacent to the American landing sectors The survey augmented previously collected magnetometer and high-resolution sidescan sonar data using a Reson 8125 high-resolution focused multibeam sonar with 240, 0.5° (at nadir) beams distributed over a 120° swath. The team investigated 21 areas in water depths ranging from about three -to 30 meters (m); some areas contained individual targets such as landing craft, barges, a destroyer, troop carrier, etc., while others contained multiple smaller

  15. The Herschel/HIFI spectral survey of OMC-2 FIR 4 (CHESS). An overview of the 480 to 1902 GHz range

    Science.gov (United States)

    Kama, M.; López-Sepulcre, A.; Dominik, C.; Ceccarelli, C.; Fuente, A.; Caux, E.; Higgins, R.; Tielens, A. G. G. M.; Alonso-Albi, T.

    2013-08-01

    Context. Broadband spectral surveys of protostars offer a rich view of the physical, chemical and dynamical structure and evolution of star-forming regions. The Herschel Space Observatory opened up the terahertz regime to such surveys, giving access to the fundamental transitions of many hydrides and to the high-energy transitions of many other species. Aims: A comparative analysis of the chemical inventories and physical processes and properties of protostars of various masses and evolutionary states is the goal of the Herschel CHEmical Surveys of Star forming regions (CHESS) key program. This paper focusses on the intermediate-mass protostar, OMC-2 FIR 4. Methods: We obtained a spectrum of OMC-2 FIR 4 in the 480 to 1902 GHz range with the HIFI spectrometer onboard Herschel and carried out the reduction, line identification, and a broad analysis of the line profile components, excitation, and cooling. Results: We detect 719 spectral lines from 40 species and isotopologs. The line flux is dominated by CO, H2O, and CH3OH. The line profiles are complex and vary with species and upper level energy, but clearly contain signatures from quiescent gas, a broad component likely due to an outflow, and a foreground cloud. Conclusions: We find abundant evidence for warm, dense gas, as well as for an outflow in the field of view. Line flux represents 2% of the 7 L⊙ luminosity detected with HIFI in the 480 to 1250 GHz range. Of the total line flux, 60% is from CO, 13% from H2O and 9% from CH3OH. A comparison with similar HIFI spectra of other sources is set to provide much new insight into star formation regions, a case in point being a difference of two orders of magnitude in the relative contribution of sulphur oxides to the line cooling of Orion KL and OMC-2 FIR 4. Appendix A is available in electronic form at http://www.aanda.org

  16. The Spitzer Infrared Nearby Galaxies Survey: A High-Resolution Spectroscopy Anthology

    Science.gov (United States)

    Dale, Daniel A.; SINGS Team

    2009-05-01

    Results from high resolution mid-infrared spectroscopy are presented for 155 nuclear and extranuclear regions from SINGS. The SINGS sample shows a wide range in the ratio of [SIII]18.71/[SIII]33.48, but the average ratio of the ensemble indicates a typical interstellar electron density of 300--400 cm-3 on 23"x15" scales and 500--600 cm-3 using 11"x9" apertures, independent of whether the region probed is a star-forming nuclear, a star-forming extranuclear, or an AGN environment. Evidence is provided that variations in gas-phase metallicity play an important role in driving variations in radiation field hardness, as indicated by [NeIII]15.56/[NeII]12.81, for regions powered by star formation. Conversely, the radiation hardness for galaxy nuclei powered by accretion around a massive black hole is independent of metal abundance. Furthermore, for metal-rich environments AGN are distinguishable from star-forming regions by significantly larger [NeIII]15.56/[NeII]12.81 ratios. Finally, [FeII]25.99/[NeII]12.81 versus [SiII]34.82/[SIII]33.48 also provides an empirical method for discerning AGN from normal star-forming sources. However, similar to [NeIII]15.56/[NeII]12.81, these mid-infrared line ratios lose their AGN/star-formation diagnostic powers for very low metallicity star-forming systems with hard radiation fields.

  17. High-Resolution Imaging of Dense Gas Structure and Kinematics in Nearby Molecular Clouds with the CARMA Large Area Star Formation Survey

    Science.gov (United States)

    Storm, Shaye

    This thesis utilizes new observations of dense gas in molecular clouds to develop an empirical framework for how clouds form structures which evolve into young cores and stars. Previous observations show the general turbulent and hierarchical nature of clouds. However, current understanding of the star formation pathway is limited by existing data that do not combine angular resolution needed to resolve individual cores with area coverage required to capture entire star-forming regions and with tracers that can resolve gas motions. The original contributions of this thesis to astrophysical research are the creation and analysis of the largest-area high-angular-resolution maps of dense gas in molecular clouds to-date, and the development of a non-binary dendrogram algorithm to quantify the hierarchical nature and three-dimensional morphology of cloud structure. I first describe the CARMA Large Area Star Formation Survey, which provides spectrally imaged N2H+, HCO+, and HCN (J = 1→0) emission across diverse regions of the Perseus and Serpens Molecular Clouds. I then present a detailed analysis of the Barnard 1 and L1451 regions in Perseus. A non-binary dendrogram analysis of Barnard 1 N2H emission and all L1451 emission shows that the most hierarchically complex gas corresponds with sub-regions actively forming young stars. I estimate the typical depth of molecular emission in each region using the spatial and kinematic properties of dendrogram-identified structures. Barnard 1 appears to be a sheet-like region at the largest scales with filamentary substructure, while the L1451 region is composed of more spatially distinct ellipsoidal structures. I then do a uniform comparison of the hierarchical structure and young stellar content of all five regions. The more evolved regions with the most young stellar objects (YSOs) and strongest emission have formed the most hierarchical levels. However, all regions show similar mean branching properties at each level

  18. [Review of digital ground object spectral library].

    Science.gov (United States)

    Zhou, Xiao-Hu; Zhou, Ding-Wu

    2009-06-01

    A higher spectral resolution is the main direction of developing remote sensing technology, and it is quite important to set up the digital ground object reflectance spectral database library, one of fundamental research fields in remote sensing application. Remote sensing application has been increasingly relying on ground object spectral characteristics, and quantitative analysis has been developed to a new stage. The present article summarized and systematically introduced the research status quo and development trend of digital ground object reflectance spectral libraries at home and in the world in recent years. Introducing the spectral libraries has been established, including desertification spectral database library, plants spectral database library, geological spectral database library, soil spectral database library, minerals spectral database library, cloud spectral database library, snow spectral database library, the atmosphere spectral database library, rocks spectral database library, water spectral database library, meteorites spectral database library, moon rock spectral database library, and man-made materials spectral database library, mixture spectral database library, volatile compounds spectral database library, and liquids spectral database library. In the process of establishing spectral database libraries, there have been some problems, such as the lack of uniform national spectral database standard and uniform standards for the ground object features as well as the comparability between different databases. In addition, data sharing mechanism can not be carried out, etc. This article also put forward some suggestions on those problems.

  19. High-resolution aeromagnetic survey of the Teide volcano (Canary Islands: a preliminary analysis

    Directory of Open Access Journals (Sweden)

    J. M. Torta

    1997-06-01

    Full Text Available To contribute to our understanding of the structure of the Teide volcano, a detailed aeromagnetic survey was carried out covering the area of Las Cañadas caldera and the Teide-Pico Viejo complex. Taking into account the rugged relief of the area (altitude ranges from sea level to almost 4000 m, a terrain correction has been applied. As a first approximation, the topography has been characterized by a uniform magnetization of 5 Am-1 (based on field and laboratory rock magnetic data. Several enhancement techniques have been applied to the residual map (original map minus topographic effect, such as reduction to the pole, pseudogravity integration and upward continuation. In the reduced-to-the-pole map the large positive anomaly that appears centered to the north of Pico Viejo is noteworthy and could be caused by a basaltic intrusion responsible for the last eruptions in this area. Also, a small magnetic low appears over Teide peak, which should be related to slightly-magnetized shallow phonolitic materials. The main tectonic direction of Tenerife, SW-NE, is also clearly reflected on the magnetic anomaly map. The comparison between the pseudogravity and the Bouguer anomaly maps indicates a good correlation between magnetic and gravimetric sources.

  20. High-resolution gravity and seismic-refraction surveys of the Smoke Tree Wash area, Joshua Tree National Park, California

    Science.gov (United States)

    Langenheim, Victoria E.; Rymer, Michael J.; Catchings, Rufus D.; Goldman, Mark R.; Watt, Janet T.; Powell, Robert E.; Matti, Jonathan C.

    2016-03-02

    We describe high-resolution gravity and seismic refraction surveys acquired to determine the thickness of valley-fill deposits and to delineate geologic structures that might influence groundwater flow beneath the Smoke Tree Wash area in Joshua Tree National Park. These surveys identified a sedimentary basin that is fault-controlled. A profile across the Smoke Tree Wash fault zone reveals low gravity values and seismic velocities that coincide with a mapped strand of the Smoke Tree Wash fault. Modeling of the gravity data reveals a basin about 2–2.5 km long and 1 km wide that is roughly centered on this mapped strand, and bounded by inferred faults. According to the gravity model the deepest part of the basin is about 270 m, but this area coincides with low velocities that are not characteristic of typical basement complex rocks. Most likely, the density contrast assumed in the inversion is too high or the uncharacteristically low velocities represent highly fractured or weathered basement rocks, or both. A longer seismic profile extending onto basement outcrops would help differentiate which scenario is more accurate. The seismic velocities also determine the depth to water table along the profile to be about 40–60 m, consistent with water levels measured in water wells near the northern end of the profile.

  1. The TESS-HERMES survey data release 1: high-resolution spectroscopy of the TESS southern continuous viewing zone

    Science.gov (United States)

    Sharma, Sanjib; Stello, Dennis; Buder, Sven; Kos, Janez; Bland-Hawthorn, Joss; Asplund, Martin; Duong, Ly; Lin, Jane; Lind, Karin; Ness, Melissa; Huber, Daniel; Zwitter, Tomaz; Traven, Gregor; Hon, Marc; Kafle, Prajwal R.; Khanna, Shourya; Saddon, Hafiz; Anguiano, Borja; Casey, Andrew R.; Freeman, Ken; Martell, Sarah; De Silva, Gayandhi M.; Simpson, Jeffrey D.; Wittenmyer, Rob A.; Zucker, Daniel B.

    2018-01-01

    The Transiting Exoplanet Survey Satellite (TESS) will provide high-precision time series photometry for millions of stars with at least a half-hour cadence. Of particular interest are the circular regions of 12° radius centred around the ecliptic poles that will be observed continuously for a full year. Spectroscopic stellar parameters are desirable to characterize and select suitable targets for TESS, whether they are focused on exploring exoplanets, stellar astrophysics or Galactic archaeology. Here, we present spectroscopic stellar parameters (Teff, log g, [Fe/H], v sin i, vmicro) for about 16 000 dwarf and subgiant stars in TESS' southern continuous viewing zone. For almost all the stars, we also present Bayesian estimates of stellar properties including distance, extinction, mass, radius and age using theoretical isochrones. Stellar surface gravity and radius are made available for an additional set of roughly 8500 red giants. All our target stars are in the range 10 using the High Efficiency and Resolution Multi-Element Spectrograph (HERMES; R ∼ 28 000) at the Anglo-Australian Telescope as part of the TESS-HERMES survey. Comparing our results with the TESS Input Catalogue (TIC) shows that the TIC is generally efficient in separating dwarfs and giants, but it has flagged more than 100 cool dwarfs (Teff < 4800 K) as giants, which ought to be high-priority targets for the exoplanet search. The catalogue can be accessed via http://www.physics.usyd.edu.au/tess-hermes/, or at Mikulski Archive for Space Telescopes (MAST).

  2. A crisis resolution and home treatment team in Norway: a longitudinal survey study Part 2. Provision of professional services

    Directory of Open Access Journals (Sweden)

    Karlsson Bengt

    2012-09-01

    Full Text Available Abstract Background Crisis resolution and home treatment (CRHT is an emerging mode of delivering acute mental health care in the community. There is a paucity of knowledge regarding the workings of CRHT in the literature. This is the second paper in a series of three from the longitudinal survey of patients of a CRHT team in Norway, which was aimed at describing the characteristics of patients served, professional services provided, and clinical outcomes. This report focuses on the provision of professional services by the team. Methods The project was a descriptive, quantitative study based on the patient data from a longitudinal survey of one CRHT team in Norway. The participants of the survey, a total of 363 patients, constituted the complete registration of patients of this team in the period from February 2008 to July 2009. Results The average length of service by the team was about 15 days, and those with depression as the major symptom had the longest mean length of stay on the team. The team was engaged in providing a variety of services including individual treatments involving multiple professionals, group treatment meetings, and coordination activities involving external service sectors. While the type of professionals providing individual treatment was not associated with the severity level of clinical problems, those receiving various group treatment meetings had more serious level of clinical symptoms than those not receiving group treatment meetings. In addition coordination activities involving healthcare professionals and social services in the community were in line with the patients' clinical and social needs. The results of the study show that the team functioned effectively in addressing the general guidelines for the functioning of CRHT teams.

  3. Magnetically-coupled microcalorimeter arrays for x-ray astrophysics with sub-eV spectral resolution and large format capability Project

    Data.gov (United States)

    National Aeronautics and Space Administration — "We propose to develop a revolutionary x-ray camera for astrophysical imaging spectroscopy. High-resolution x-ray spectroscopy is a powerful tool for studying the...

  4. Development of High Spectral Resolution Technique for Registration Quasielastic Light Scattering Spectra Including Rayleigh and Brillouin Scattering as a Diagnostic Tool in Materials Characterization

    National Research Council Canada - National Science Library

    Bairamov, Bakhysh

    2004-01-01

    ...: As detailed in an on-line proposal the contractor will: 1) develop and build an optical device, fitted to a Fabry-Perot interferometer, to perform high-resolution quasieleastic light scattering spectroscopy; 2...

  5. Second byurakan spectral sky survey. IV. Results for region centered on /chi/ = 12 /sup h/ 22 /sup m/, δ = +55 /sup o/ 00

    International Nuclear Information System (INIS)

    Makaryan, B.E.; Erastova, L.K.; Stepanyan, D.A.

    1986-01-01

    The fourth list of objects of the second Byurkan spectral sky survey in the 4 0 x 4 0 region centered on alpha= 12 /sup h/ 22 /sup m/, delta = +55 0 00' is presented. The observations were made with the 40''-52'' Schmidt telescope of the Byurkan Observatory with a set of three objective prisms. The list contains data on 106 objects and galxies and 12 blue stars. The distribution of the objects with respect to types is as follows: 16 candidates for QSO, 29 for BSO, 32 galaxies with appreciable ultraviolet continuum, among which weak Seyfert features are suspected for three, and 29 emission galaxies without appreciable ultraviolet continuum. The surface density of QSO and Seyferts down to 19 /sup m/ is more than one per square degree

  6. Herschel Observations of Extraordinary Sources: Analysi sof the HIFI 1.2 THz Wide Spectral Survey toward Orion KL II. Chemical Implications

    Science.gov (United States)

    Crockett, N. R.; Bergin, E. A.; Neill, J. L.; Favre, C.; Blake, G. A.; Herbst, E.; Anderson, D. E.; Hassel, G. E.

    2015-06-01

    We present chemical implications arising from spectral models fit to the Herschel/HIFI spectral survey toward the Orion Kleinmann-Low nebula (Orion KL). We focus our discussion on the eight complex organics detected within the HIFI survey utilizing a novel technique to identify those molecules emitting in the hottest gas. In particular, we find the complex nitrogen bearing species CH3CN, C2H3CN, C2H5CN, and NH2CHO systematically trace hotter gas than the oxygen bearing organics CH3OH, C2H5OH, CH3OCH3, and CH3OCHO, which do not contain nitrogen. If these complex species form predominantly on grain surfaces, this may indicate N-bearing organics are more difficult to remove from grain surfaces than O-bearing species. Another possibility is that hot (Tkin ∼ 300 K) gas phase chemistry naturally produces higher complex cyanide abundances while suppressing the formation of O-bearing complex organics. We compare our derived rotation temperatures and molecular abundances to chemical models, which include gas-phase and grain surface pathways. Abundances for a majority of the detected complex organics can be reproduced over timescales ≳105 years, with several species being underpredicted by less than 3σ. Derived rotation temperatures for most organics, furthermore, agree reasonably well with the predicted temperatures at peak abundance. We also find that sulfur bearing molecules that also contain oxygen (i.e., SO, SO2, and OCS) tend to probe the hottest gas toward Orion KL, indicating the formation pathways for these species are most efficient at high temperatures. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  7. Cross-calibration of Medium Resolution Earth Observing Satellites by Using EO-1 Hyperion-derived Spectral Surface Reflectance from "Lunar Cal Sites"

    Science.gov (United States)

    Ungar, S.

    2017-12-01

    Over the past 3 years, the Earth Observing-one (EO-1) Hyperion imaging spectrometer was used to slowly scan the lunar surface at a rate which results in up to 32X oversampling to effectively increase the SNR. Several strategies, including comparison against the USGS RObotic Lunar Observatory (ROLO) mode,l are being employed to estimate the absolute and relative accuracy of the measurement set. There is an existing need to resolve discrepancies as high as 10% between ROLO and solar based calibration of current NASA EOS assets. Although the EO-1 mission was decommissioned at the end of March 2017, the development of a well-characterized exoatmospheric spectral radiometric database, for a range of lunar phase angles surrounding the fully illuminated moon, continues. Initial studies include a comprehensive analysis of the existing 17-year collection of more than 200 monthly lunar acquisitions. Specific lunar surface areas, such as a lunar mare, are being characterized as potential "lunar calibration sites" in terms of their radiometric stability in the presence of lunar nutation and libration. Site specific Hyperion-derived lunar spectral reflectance are being compared against spectrographic measurements made during the Apollo program. Techniques developed through this activity can be employed by future high-quality orbiting imaging spectrometers (such as HyspIRI and EnMap) to further refine calibration accuracies. These techniques will enable the consistent cross calibration of existing and future earth observing systems (spectral and multi-spectral) including those that do not have lunar viewing capability. When direct lunar viewing is not an option for an earth observing asset, orbiting imaging spectrometers can serve as transfer radiometers relating that asset's sensor response to lunar values through near contemporaneous observations of well characterized stable CEOS test sites. Analysis of this dataset will lead to the development of strategies to ensure more

  8. Stratigraphic significance and resolution of spectral reflectance logs in Lower Devonian carbonates of the Barrandian area, Czech Republic; a correlation with magnetic susceptibility and gamma-ray logs

    Czech Academy of Sciences Publication Activity Database

    Koptíková, Leona; Bábek, O.; Hladil, Jindřich; Kalvoda, J.; Slavík, Ladislav

    2010-01-01

    Roč. 225, 3/4 (2010), s. 83-98 ISSN 0037-0738 R&D Projects: GA AV ČR IAAX00130702; GA ČR GA205/08/0767 Institutional research plan: CEZ:AV0Z30130516 Keywords : VIS spectral reflectance * cyclostratigraphy * sea -level changes * Lower Devonian * red pelagic carbonates * diagenesis Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.685, year: 2010

  9. Long-Term, High-Resolution Survey of Atmospheric Aerosols over Egypt with NASA’s MODIS Data

    Directory of Open Access Journals (Sweden)

    Mohammed Shokr

    2017-10-01

    Full Text Available A decadal survey of atmospheric aerosols over Egypt and selected cities and regions is presented using daily aerosol optical depth (AOD data from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS at 550 nm wavelength onboard the Aqua satellite. We explore the AOD spatio-temporal variations over Egypt during a 12-year record (2003 to 2014 using the MODIS high-resolution (10 km Level 2 data product. Five cities and two geographic regions that feature different landscape and human activities were selected for detailed analysis. For most of the examined areas, AOD is found to be most frequent in the 0.2–0.3 range, and the highest mean AOD was found to be over Cairo, Alexandria, and the Nile Delta region. Severe events are identified based on AOD higher than a selected threshold. Most of these events are engendered by sand and dust storms that originate from the Western Desert during January–April. Spatial analysis indicates that they cover the Nile Delta region, including cities of Cairo and Alexandria, on the same day. Examination of the spatial gradient of AOD along the four cardinal directions originating from the city’s center reveals seasonally dependent gradients in some cases. The gradients have been linked to locations of industrial activity. No trend of AOD has been observed in the studied areas during the study period, though data from Cairo and Asyut reveal a slight linear increase of AOD. Considering Cairo is commonly perceived as a city of poor air quality, the results show that local events are fairly constrained. The study highlights spatial and seasonal distributions of AOD and links them to geographic and climatic conditions across the country.

  10. Assessing subaqueous mudslide hazard on the Mississippi River delta front, Part 2: Insights revealed through high-resolution geophysical surveying

    Science.gov (United States)

    Obelcz, J.; Xu, K.; Bentley, S. J.; Georgiou, I. Y.; Maloney, J. M.; Miner, M. D.; Hanegan, K.; Keller, G.

    2014-12-01

    The northern Gulf of Mexico, including the subaqueous Mississippi River delta front (MRDF), has been productive for oil and gas development since the early 1900s. In 1969 cyclic seafloor wave loading associated with the passage of Hurricane Camille triggered subaqueous mudflows across the MRDF, destroying several offshore oil platforms. This incident spurred geophysical and geotechnical studies of the MRDF, which found that the delta front is prone to mass failures on gentle gradients (gas production, and (3) the frequent passage of tropical cyclones. In June 2014, a geophysical pilot study was conducted 8 km southwest of Southwest Pass, the distributary that currently receives the largest fraction of Mississippi River sediment supply. The resultant dataset encompasses 216 km of subbottom Chirp seismic profiles and a 60 km2 grid of bathymetry and sidescan data. Preliminary interpretation of these data shows the survey area can be classified into four primary sedimentary facies: mudflow gullies, mudflow lobes, undisturbed prodelta, and undisturbed delta front. Subbottom profiles reveal extensive biogenic gas from 20 to about 80 m water depths on the delta front; sidescan data show a variety of bottleneck slides, mudflow gullies and mudflow noses. Previous studies have attempted to constrain the periodicity and magnitude of subaqueous mudslides on the MRDF. However, large age gaps and varied resolution between datasets result in ambiguity regarding the cause and magnitude of observed bathymetric changes. We present high-temporal resolution MRDF bathymetric variations from 2005 (post Hurricane Katrina), 2009 (relatively quiescent storm period), and 2014 (post 2011 Mississippi River flood). These data yield better magnitude and timing estimates of mass movements. This exercise represents a first step towards (1) assembling a comprehensive geologic dataset upon which future MRDF geohazard assessments can be founded, and (2) understanding the dynamics of a massive

  11. MERIS Level-2 Reduced Resolution - OBPG Processing

    Data.gov (United States)

    National Aeronautics and Space Administration — MERIS is a programmable, medium-spectral resolution, imaging spectrometer operating in the solar reflective spectral range. Fifteen spectral bands can be selected by...

  12. MERIS Level-1B Reduced Resolution

    Data.gov (United States)

    National Aeronautics and Space Administration — MERIS is a programmable, medium-spectral resolution, imaging spectrometer operating in the solar reflective spectral range. Fifteen spectral bands can be selected by...

  13. The development of a modified spectral ripple test.

    Science.gov (United States)

    Aronoff, Justin M; Landsberger, David M

    2013-08-01

    Poor spectral resolution can be a limiting factor for hearing impaired listeners, particularly for complex listening tasks such as speech understanding in noise. Spectral ripple tests are commonly used to measure spectral resolution, but these tests contain a number of potential confounds that can make interpretation of the results difficult. To measure spectral resolution while avoiding those confounds, a modified spectral ripple test with dynamically changing ripples was created, referred to as the spectral-temporally modulated ripple test (SMRT). This paper describes the SMRT and provides evidence that it is sensitive to changes in spectral resolution.

  14. The High Time Resolution Universe Pulsar Survey - XII. Galactic plane acceleration search and the discovery of 60 pulsars

    Science.gov (United States)

    Ng, C.; Champion, D. J.; Bailes, M.; Barr, E. D.; Bates, S. D.; Bhat, N. D. R.; Burgay, M.; Burke-Spolaor, S.; Flynn, C. M. L.; Jameson, A.; Johnston, S.; Keith, M. J.; Kramer, M.; Levin, L.; Petroff, E.; Possenti, A.; Stappers, B. W.; van Straten, W.; Tiburzi, C.; Eatough, R. P.; Lyne, A. G.

    2015-07-01

    We present initial results from the low-latitude Galactic plane region of the High Time Resolution Universe pulsar survey conducted at the Parkes 64-m radio telescope. We discuss the computational challenges arising from the processing of the terabyte-sized survey data. Two new radio interference mitigation techniques are introduced, as well as a partially coherent segmented acceleration search algorithm which aims to increase our chances of discovering highly relativistic short-orbit binary systems, covering a parameter space including potential pulsar-black hole binaries. We show that under a constant acceleration approximation, a ratio of data length over orbital period of ≈0.1 results in the highest effectiveness for this search algorithm. From the 50 per cent of data processed thus far, we have redetected 435 previously known pulsars and discovered a further 60 pulsars, two of which are fast-spinning pulsars with periods less than 30 ms. PSR J1101-6424 is a millisecond pulsar whose heavy white dwarf (WD) companion and short spin period of 5.1 ms indicate a rare example of full-recycling via Case A Roche lobe overflow. PSR J1757-27 appears to be an isolated recycled pulsar with a relatively long spin period of 17 ms. In addition, PSR J1244-6359 is a mildly recycled binary system with a heavy WD companion, PSR J1755-25 has a significant orbital eccentricity of 0.09 and PSR J1759-24 is likely to be a long-orbit eclipsing binary with orbital period of the order of tens of years. Comparison of our newly discovered pulsar sample to the known population suggests that they belong to an older population. Furthermore, we demonstrate that our current pulsar detection yield is as expected from population synthesis.

  15. A New Radio Spectral Line Survey of Planetary Nebulae: Exploring Radiatively-driven Heating and Chemistry of Molecular Gas

    Science.gov (United States)

    Bublitz, Jesse; Kastner, Joel H.; Santander-García, Miguel; Montez, Rodolfo; Alcolea, Javier; Balick, Bruce; Bujarrabal, Valentín

    2018-01-01

    We report the results of a survey of mm-wave molecular line emission from nine nearby (Radioastronomie Millimétrique (IRAM) 30 m telescope. Our sample comprises molecule-rich PNe spanning a wide range of central star UV luminosities as well as central star and nebular X-ray emission properties. Nine molecular line frequencies were chosen to investigate the molecular chemistry of these nebulae. New detections of one or more of five molecules -- the molecular mass tracer 13CO and the chemically important trace species HCO+, CN, HCN, and HNC -- were made in at least one PN. We present analysis of emission line flux ratios that are potential diagnostics of the influence that ultraviolet and X-ray radiation have on the chemistry of residual molecular gas in PNe.

  16. The CHESS Survey of the L1157-B1 Shock Region: CO Spectral Signatures of Jet-driven Bow Shocks

    Science.gov (United States)

    Lefloch, B.; Cabrit, S.; Busquet, G.; Codella, C.; Ceccarelli, C.; Cernicharo, J.; Pardo, J. R.; Benedettini, M.; Lis, D. C.; Nisini, B.

    2012-10-01

    The unprecedented sensitivity of Herschel coupled with the high resolution of the HIFI spectrometer permits studies of the intensity-velocity relationship I(v) in molecular outflows, over a higher excitation range than possible up to now. Over the course of the CHESS Key Program, we have observed toward the bright bow shock region L1157-B1, the CO rotational transitions between J = 5-4 and J = 16-15 with HIFI, and the J = 1-0, 2-1, and 3-2 with the IRAM 30 m and the Caltech Submillimeter Observatory telescopes. We find that all the line profiles I CO(v) are well fit by a linear combination of three exponential laws vpropexp (- |v/v 0|) with v 0 = 12.5, 4.4, and 2.5 km s-1. The first component dominates the CO emission at J >= 13, as well as the high-excitation lines of SiO and H2O. The second component dominates for 3 = 105-106 cm-3) close to LTE up to J = 20. We find that the CO J = 2-1 intensity-velocity relation observed in various other molecular outflows is satisfactorily fit by similar exponential laws, which may hold an important clue to their entrainment process.

  17. Formaldehyde in Alcoholic Beverages: Large Chemical Survey Using Purpald Screening Followed by Chromotropic Acid Spectrophotometry with Multivariate Curve Resolution

    Directory of Open Access Journals (Sweden)

    Julien A. Jendral

    2011-01-01

    Full Text Available A strategy for analyzing formaldehyde in beer, wine, spirits, and unrecorded alcohol was developed, and 508 samples from worldwide origin were analyzed. In the first step, samples are qualitatively screened using a simple colorimetric test with the purpald reagent, which is extremely sensitive for formaldehyde (detection limit 0.1 mg/L. 210 samples (41% gave a positive purpald reaction. In the second step, formaldehyde in positive samples is confirmed by quantitative spectrophotometry of the chromotropic acid-formaldehyde derivative combined with Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS. Calculation of UV-VIS and 13C NMR spectra confirmed the monocationic dibenzoxanthylium structure as the product of the reaction and disproved the widely cited para,para-quinoidal structure. Method validation for the spectrophotometric procedure showed a detection limit of 0.09 mg/L and a precision of 4.2–8.2% CV. In total, 132 samples (26% contained formaldehyde with an average of 0.27 mg/L (range 0–14.4 mg/L. The highest incidence occurred in tequila (83%, Asian spirits (59%, grape marc (54%, and brandy (50%. Our survey showed that only 9 samples (1.8% had formaldehyde levels above the WHO IPCS tolerable concentration of 2.6 mg/L.

  18. Formaldehyde in alcoholic beverages: large chemical survey using purpald screening followed by chromotropic Acid spectrophotometry with multivariate curve resolution.

    Science.gov (United States)

    Jendral, Julien A; Monakhova, Yulia B; Lachenmeier, Dirk W

    2011-01-01

    A strategy for analyzing formaldehyde in beer, wine, spirits, and unrecorded alcohol was developed, and 508 samples from worldwide origin were analyzed. In the first step, samples are qualitatively screened using a simple colorimetric test with the purpald reagent, which is extremely sensitive for formaldehyde (detection limit 0.1 mg/L). 210 samples (41%) gave a positive purpald reaction. In the second step, formaldehyde in positive samples is confirmed by quantitative spectrophotometry of the chromotropic acid-formaldehyde derivative combined with Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS). Calculation of UV-VIS and (13)C NMR spectra confirmed the monocationic dibenzoxanthylium structure as the product of the reaction and disproved the widely cited para,para-quinoidal structure. Method validation for the spectrophotometric procedure showed a detection limit of 0.09 mg/L and a precision of 4.2-8.2% CV. In total, 132 samples (26%) contained formaldehyde with an average of 0.27 mg/L (range 0-14.4 mg/L). The highest incidence occurred in tequila (83%), Asian spirits (59%), grape marc (54%), and brandy (50%). Our survey showed that only 9 samples (1.8%) had formaldehyde levels above the WHO IPCS tolerable concentration of 2.6 mg/L.

  19. The implementation of crisis resolution home treatment teams in wales: results of the national survey 2007-2008.

    Science.gov (United States)

    Jones, Richard; Jordan, Sue

    2010-02-18

    In mental health nursing, Crisis Resolution and Home Treatment (CRHT) services are key components of the shift from in-patient to community care. CRHT has been developed mainly in urban settings, and deployment in more rural areas has not been examined. We aimed to evaluate CRHT services' progress towards policy targets. All 18 CRHT teams in Wales were surveyed. A service profile questionnaire was distributed to team leaders. Fourteen of 18 teams responded in full. All but one were led by nurses, who formed the main professional group. All teams reported providing an alternative to hospital admission and assisting early discharge. With one exception, teams were 'gatekeeping' hospital beds. There was some divergence in clients seen, perceived impact of the service, operational hours, distances travelled, team structure, input of consultant psychiatrists and caseloads. We found some differences between the 8 urban teams and the 6 teams serving rural or mixed areas: rural teams travelled more, had fewer inpatient beds, and less medical input (0.067 compared to 0.688 whole time equivalents).. Most respondents felt that resource constraints were limiting further developments. Teams met standards for CHRT services in Wales; however, these are less onerous than those in England, particularly in relation to operational hours and staffing complement. As services develop, it will be important to ensure that rural and mixed areas receive the same level of input as urban areas.

  20. THE CHESS SURVEY OF THE L1157-B1 SHOCK REGION: CO SPECTRAL SIGNATURES OF JET-DRIVEN BOW SHOCKS

    International Nuclear Information System (INIS)

    Lefloch, B.; Codella, C.; Ceccarelli, C.; Cabrit, S.; Busquet, G.; Benedettini, M.; Cernicharo, J.; Pardo, J. R.; Lis, D. C.; Nisini, B.

    2012-01-01

    The unprecedented sensitivity of Herschel coupled with the high resolution of the HIFI spectrometer permits studies of the intensity-velocity relationship I(v) in molecular outflows, over a higher excitation range than possible up to now. Over the course of the CHESS Key Program, we have observed toward the bright bow shock region L1157-B1, the CO rotational transitions between J = 5-4 and J = 16-15 with HIFI, and the J = 1-0, 2-1, and 3-2 with the IRAM 30 m and the Caltech Submillimeter Observatory telescopes. We find that all the line profiles I CO (v) are well fit by a linear combination of three exponential laws ∝exp (– |v/v 0 |) with v 0 = 12.5, 4.4, and 2.5 km s –1 . The first component dominates the CO emission at J ≥ 13, as well as the high-excitation lines of SiO and H 2 O. The second component dominates for 3 ≤ J up ≤ 10 and the third one for J up ≤ 2. We show that these exponentials are the signature of quasi-isothermal shocked gas components: the impact of the jet against the L1157-B1 bow shock (T k ≅ 210 K), the walls of the outflow cavity associated with B1 (T k ≅ 64 K), and the older cavity L1157-B2 (T k ≅ 23 K), respectively. Analysis of the CO line flux in the large-velocity gradient approximation further shows that the emission arises from dense gas (n(H 2 ) ≥ 10 5 -10 6 cm –3 ) close to LTE up to J = 20. We find that the CO J = 2-1 intensity-velocity relation observed in various other molecular outflows is satisfactorily fit by similar exponential laws, which may hold an important clue to their entrainment process.

  1. A New Radio Spectral Line Survey of Planetary Nebulae: Exploring Radiatively Driven Heating and Chemistry of Molecular Gas

    Science.gov (United States)

    Bublitz, Jesse

    Planetary nebulae contain shells of cold gas and dust whose heating and chemistry is likely driven by UV and X-ray emission from their central stars and from wind-collision-generated shocks. We present the results of a survey of molecular line emissions in the 88 - 235 GHz range from nine nearby (Radioastronomie Millimetrique. Rotational transitions of nine molecules, including the well-studied CO isotopologues and chemically important trace species, were observed and the results compared with and augmented by previous studies of molecular gas in PNe. Lines of the molecules HCO+, HNC, HCN, and CN, which were detected in most objects, represent new detections for five planetary nebulae in our study. Flux ratios were analyzed to identify correlations between the central star and/or nebular ultraviolet/X-ray luminosities and the molecular chemistries of the nebulae. Analysis reveals the apparent dependence of the HNC/HCN line ratio on PN central star UV luminosity. There exists no such clear correlation between PN X-rays and various diagnostics of PN molecular chemistry. The correlation between HNC/HCN ratio and central star UV luminosity hints at the potential of molecular emission line studies of PNe for improving our understanding of the role that high-energy radiation plays in the heating and chemistry of photodissociation regions.

  2. Gemini/GMOS Transmission Spectral Survey: Complete Optical Transmission Spectrum of the Hot Jupiter WASP-4b

    Science.gov (United States)

    Huitson, C. M.; Désert, J.-M.; Bean, J. L.; Fortney, J. J.; Stevenson, K. B.; Bergmann, M.

    2017-09-01

    We present the complete optical transmission spectrum of the hot Jupiter WASP-4b from 440 to 940 nm at R ˜ 400-1500 obtained with the Gemini Multi-Object Spectrometers (GMOS); this is the first result from a comparative exoplanetology survey program of close-in gas giants conducted with GMOS. WASP-4b has an equilibrium temperature of 1700 K and is favorable to study in transmission due to its large scale height (370 km). We derive the transmission spectrum of WASP-4b using four transits observed with the MOS technique. We demonstrate repeatable results across multiple epochs with GMOS, and derive a combined transmission spectrum at a precision about twice above photon noise, which is roughly equal to one atmospheric scale height. The transmission spectrum is well fitted with a uniform opacity as a function of wavelength. The uniform opacity and absence of a Rayleigh slope from molecular hydrogen suggest that the atmosphere is dominated by clouds with condensate grain sizes of ˜1 μm. This result is consistent with previous observations of hot Jupiters since clouds have been seen in planets with similar equilibrium temperatures to WASP-4b. We describe a custom pipeline that we have written to reduce GMOS time-series data of exoplanet transits, and present a thorough analysis of the dominant noise sources in GMOS, which primarily consist of wavelength- and time-dependent displacements of the spectra on the detector, mainly due to a lack of atmospheric dispersion correction.

  3. Structure from motion, a low cost, very high resolution method for surveying glaciers using GoPros and opportunistic helicopter flights

    Science.gov (United States)

    Girod, L.; Nuth, C.; Schellenberger, T.

    2014-12-01

    The capability of structure from motion techniques to survey glaciers with a very high spatial and temporal resolution is a promising tool for better understanding the dynamic changes of glaciers. Modern software and computing power allow us to produce accurate data sets from low cost surveys, thus improving the observational capabilities on a wider range of glaciers and glacial processes. In particular, highly accurate glacier volume change monitoring and 3D movement computations will be possible Taking advantage of the helicopter flight needed to survey the ice stakes on Kronenbreen, NW Svalbard, we acquired high resolution photogrammetric data over the well-studied Midre Lovénbreen in September 2013. GoPro Hero 2 cameras were attached to the landing gear of the helicopter, acquiring two images per second. A C/A code based GPS was used for registering the stereoscopic model. Camera clock calibration is obtained through fitting together the shapes of the flight given by both the GPS logger and the relative orientation of the images. A DEM and an ortho-image are generated at 30cm resolution from 300 images collected. The comparison with a 2005 LiDAR DEM (5 meters resolution) shows an absolute error in the direct registration of about 6±3m in 3D which could be easily reduced to 1,5±1m by using fine point cloud alignment algorithms on stable ground. Due to the different nature of the acquisition method, it was not possible to use tie point based co-registration. A combination of the DEM and ortho-image is shown with the point cloud in figure below. A second photogrammetric data set will be acquired in September 2014 to survey the annual volume change and movement. These measurements will then be compared to the annual resolution glaciological stake mass balance and velocity measurements to assess the precision of the method to monitor at an annual resolution.

  4. THE CHESS SURVEY OF THE L1157-B1 SHOCK REGION: CO SPECTRAL SIGNATURES OF JET-DRIVEN BOW SHOCKS

    Energy Technology Data Exchange (ETDEWEB)

    Lefloch, B.; Codella, C.; Ceccarelli, C. [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et dAstrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041 (France); Cabrit, S. [Observatoire de Paris, LERMA, UMR 8112 du CNRS, ENS, UPMC, UCP, 61 Av. de l' Observatoire, F-75014 Paris (France); Busquet, G.; Benedettini, M. [INAF, Istituto di Astrofisica e Planetologia Spaziali, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Cernicharo, J.; Pardo, J. R. [Centro de Astrobiologia, INTA, Ctra de Torrejon a Ajalvir, km 4, E-28850 Torrejon de Ardoz, E-28850 Madrid (Spain); Lis, D. C. [California Institute of Technology, Cahill Center for Astronomy and Astrophysics 301-17, Pasadena, CA 91125 (United States); Nisini, B., E-mail: lefloch@obs.ujf-grenoble.fr [INAF, Osservatorio Astronomico di Roma, Via di Frascati 33, I-00040 Monte, Porzio Catone (Italy)

    2012-10-01

    The unprecedented sensitivity of Herschel coupled with the high resolution of the HIFI spectrometer permits studies of the intensity-velocity relationship I(v) in molecular outflows, over a higher excitation range than possible up to now. Over the course of the CHESS Key Program, we have observed toward the bright bow shock region L1157-B1, the CO rotational transitions between J = 5-4 and J = 16-15 with HIFI, and the J = 1-0, 2-1, and 3-2 with the IRAM 30 m and the Caltech Submillimeter Observatory telescopes. We find that all the line profiles I{sub CO}(v) are well fit by a linear combination of three exponential laws {proportional_to}exp (- |v/v{sub 0}|) with v{sub 0} = 12.5, 4.4, and 2.5 km s{sup -1}. The first component dominates the CO emission at J {>=} 13, as well as the high-excitation lines of SiO and H{sub 2}O. The second component dominates for 3 {<=} J{sub up} {<=} 10 and the third one for J{sub up} {<=} 2. We show that these exponentials are the signature of quasi-isothermal shocked gas components: the impact of the jet against the L1157-B1 bow shock (T{sub k} {approx_equal} 210 K), the walls of the outflow cavity associated with B1 (T{sub k} {approx_equal} 64 K), and the older cavity L1157-B2 (T{sub k} {approx_equal} 23 K), respectively. Analysis of the CO line flux in the large-velocity gradient approximation further shows that the emission arises from dense gas (n(H{sub 2}) {>=} 10{sup 5}-10{sup 6} cm{sup -3}) close to LTE up to J = 20. We find that the CO J = 2-1 intensity-velocity relation observed in various other molecular outflows is satisfactorily fit by similar exponential laws, which may hold an important clue to their entrainment process.

  5. Gemini/GMOS Transmission Spectral Survey: Complete Optical Transmission Spectrum of the Hot Jupiter WASP-4b

    Energy Technology Data Exchange (ETDEWEB)

    Huitson, C. M. [CASA, University of Colorado, 389 UCB, Boulder, CO 80309-0389 (United States); Désert, J.-M. [API, University of Amsterdam, P.O. Box 94249, 1090 GE Amsterdam (Netherlands); Bean, J. L. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Fortney, J. J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Stevenson, K. B. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bergmann, M., E-mail: catherine.huitson@colorado.edu [NOAO and Gemini Observatory, present address Palo Alto, CA (United States)

    2017-09-01

    We present the complete optical transmission spectrum of the hot Jupiter WASP-4b from 440 to 940 nm at R  ∼ 400–1500 obtained with the Gemini Multi-Object Spectrometers (GMOS); this is the first result from a comparative exoplanetology survey program of close-in gas giants conducted with GMOS. WASP-4b has an equilibrium temperature of 1700 K and is favorable to study in transmission due to its large scale height (370 km). We derive the transmission spectrum of WASP-4b using four transits observed with the MOS technique. We demonstrate repeatable results across multiple epochs with GMOS, and derive a combined transmission spectrum at a precision about twice above photon noise, which is roughly equal to one atmospheric scale height. The transmission spectrum is well fitted with a uniform opacity as a function of wavelength. The uniform opacity and absence of a Rayleigh slope from molecular hydrogen suggest that the atmosphere is dominated by clouds with condensate grain sizes of ∼1  μ m. This result is consistent with previous observations of hot Jupiters since clouds have been seen in planets with similar equilibrium temperatures to WASP-4b. We describe a custom pipeline that we have written to reduce GMOS time-series data of exoplanet transits, and present a thorough analysis of the dominant noise sources in GMOS, which primarily consist of wavelength- and time-dependent displacements of the spectra on the detector, mainly due to a lack of atmospheric dispersion correction.

  6. Gemini/GMOS Transmission Spectral Survey: Complete Optical Transmission Spectrum of the Hot Jupiter WASP-4b

    International Nuclear Information System (INIS)

    Huitson, C. M.; Désert, J.-M.; Bean, J. L.; Fortney, J. J.; Stevenson, K. B.; Bergmann, M.

    2017-01-01

    We present the complete optical transmission spectrum of the hot Jupiter WASP-4b from 440 to 940 nm at R  ∼ 400–1500 obtained with the Gemini Multi-Object Spectrometers (GMOS); this is the first result from a comparative exoplanetology survey program of close-in gas giants conducted with GMOS. WASP-4b has an equilibrium temperature of 1700 K and is favorable to study in transmission due to its large scale height (370 km). We derive the transmission spectrum of WASP-4b using four transits observed with the MOS technique. We demonstrate repeatable results across multiple epochs with GMOS, and derive a combined transmission spectrum at a precision about twice above photon noise, which is roughly equal to one atmospheric scale height. The transmission spectrum is well fitted with a uniform opacity as a function of wavelength. The uniform opacity and absence of a Rayleigh slope from molecular hydrogen suggest that the atmosphere is dominated by clouds with condensate grain sizes of ∼1  μ m. This result is consistent with previous observations of hot Jupiters since clouds have been seen in planets with similar equilibrium temperatures to WASP-4b. We describe a custom pipeline that we have written to reduce GMOS time-series data of exoplanet transits, and present a thorough analysis of the dominant noise sources in GMOS, which primarily consist of wavelength- and time-dependent displacements of the spectra on the detector, mainly due to a lack of atmospheric dispersion correction.

  7. Auditory-model based assessment of the effects of hearing loss and hearing-aid compression on spectral and temporal resolution

    DEFF Research Database (Denmark)

    Kowalewski, Borys; MacDonald, Ewen; Strelcyk, Olaf

    2016-01-01

    . However, due to the complexity of speech and its robustness to spectral and temporal alterations, the effects of DRC on speech perception have been mixed and controversial. The goal of the present study was to obtain a clearer understanding of the interplay between hearing loss and DRC by means......Most state-of-the-art hearing aids apply multi-channel dynamic-range compression (DRC). Such designs have the potential to emulate, at least to some degree, the processing that takes place in the healthy auditory system. One way to assess hearing-aid performance is to measure speech intelligibility....... Outcomes were simulated using the auditory processing model of Jepsen et al. (2008) with the front end modified to include effects of hearing impairment and DRC. The results were compared to experimental data from normal-hearing and hearing-impaired listeners....

  8. Submerged Humid Tropical Karst Landforms Observed By High-Resolution Multibeam Survey in Nagura Bay, Ishigaki Island, Southwestern Japan

    Science.gov (United States)

    Kan, H.; Urata, K.; Nagao, M.; Hori, N.; Fujita, K.; Yokoyama, Y.; Nakashima, Y.; Ohashi, T.; Goto, K.; Suzuki, A.

    2014-12-01

    Submerged tropical karst features were discovered in Nagura Bay on Ishigaki Island in the South Ryukyu Islands, Japan. This is the first description of submerged humid tropical karst using multibeam bathymetry. We conducted a broadband multibeam survey in the central area of Nagura Bay (1.85 × 2.7 km) and visualized the high-resolution bathymetric results with a grid size of 1 m over a depth range of 1.6-58.5 m. Various types of humid tropical karst landforms were found to coexist within the bay, including fluviokarst, doline karst, cockpit karst, polygonal karst, uvalas, and mega-dolines. We assume that Nagura Bay was a large karst basin in which older limestone remained submerged, thus preventing corrosion and the accumulation of reef sediments during periods of submersion, whereas the limestone outcropping on land was corroded during multiple interglacial and glacial periods. Based on our bathymetric result together with aerial photographs of the coastal area, we conclude that the submerged karst landscape has likely developed throughout the whole of Nagura Bay, covering an area of ~6 × 5 km. Accordingly, this area hosts the largest submerged karst in Japan. We also observed abundant coral communities during our SCUBA observations. The present marine conditions of Nagura Bay are characterized by low energy (calm sea) and low irradiance owing to the terrestrial influence. Such conditions have been emphasized by the presence of large undulating landforms, which cause decreases in wave intensity and irradiance with depth. These characteristics have acted to establish unique conditions compared to other coral reef areas in the Ryukyu Islands. It may play an important role in supporting the regional coral reef ecosystem.

  9. Second Byurakan spectral sky survey. II. Results for region centered on alpha 09h50m, delta +55 deg 00 arcmin

    International Nuclear Information System (INIS)

    Markarian, B.E.; Stepanian, D.A.

    1984-01-01

    The second list of objects in the Second Biurakan Spectral Sky Survey of the region centered on alpha 09h50m, delta +55 deg 00 arcmin is given. The list contains data on 110 objects and galaxies of a peculiar physical nature and 24 blue stars. The observations were made with the 40-52 arcsec Schmidt telescope of the Biurakan Astrophysical Observatory with a set of three objective prisms using Kodak IIIaJ and IIIaF emulsions sensitized in nitrogen. The area is found to contain 20 quasar candidates and four Seyfert galaxies, 27 blue stellar objects, 24 galaxies with an appreciable ultraviolet continuum, and 39 emission galaxies without appreciable ultraviolet radiation. The surface brightness of the quasars and Seyferts on the considered area down to the limiting magnitude 19.5 M is more than 1.5 per square degree with allowance for the already known quasars. The surface density of emission galaxies is about four per square degree. 7 references

  10. Simultaneous resolution of spectral and temporal properties of UV and visible fluorescence using single-photon counting with a position-sensitive detector

    International Nuclear Information System (INIS)

    Kelly, L.A.; Trunk, J.G.; Polewski, K.; Sutherland, J.C.

    1995-01-01

    A new fluorescence spectrometer has been assembled at the U9B beamline of the National Synchrotron Light Source to allow simultaneous multiwavelength and time-resolved fluorescence detection, as well as spatial imaging of the sample fluorescence. The spectrometer employs monochromatized, tunable UV and visible excitation light from a synchrotron bending magnet and an imaging spectrograph equipped with a single-photon sensitive emission detector. The detector is comprised of microchannel plates in series, with a resistive anode for encoding the position of the photon-derived current. The centroid position of the photon-induced electron cascade is derived in a position analyzer from the four signals measured at the corners of the resistive anode. Spectral information is obtained by dispersing the fluorescence spectrum across one dimension of the detector photocathode. Timing information is obtained by monitoring the voltage divider circuit at the last MCP detector. The signal from the MCP is used as a ''start'' signal to perform a time-correlated single photon counting experiment. The analog signal representing the position, and hence wavelength, is digitized concomitantly with the start/stop time difference and stored in the two-dimensional histogramming memory of a multiparameter analyzer

  11. Hybrid spectral CT reconstruction.

    Directory of Open Access Journals (Sweden)

    Darin P Clark

    Full Text Available Current photon counting x-ray detector (PCD technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID. In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM. Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with

  12. Hybrid spectral CT reconstruction

    Science.gov (United States)

    Clark, Darin P.

    2017-01-01

    Current photon counting x-ray detector (PCD) technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID). In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM). Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with a spectral

  13. Burial and exhumation of temperate bedrock reefs as elucidated by repetitive high-resolution sea floor sonar surveys: Spatial patterns and impacts to species' richness and diversity

    Science.gov (United States)

    Storlazzi, Curt D.; Fregoso, Theresa A.; Figurski, Jared D.; Freiwald, Jan; Lonhart, Steve I.; Finlayson, David P.

    2013-01-01

    To understand how chronic sediment burial and scour contribute to variation in the structure of algal and invertebrate communities on temperate bedrock reefs, the dynamics of the substrate and communities were monitored at locations that experience sand inundation and adjacent areas that do not. Co-located benthic scuba-transect surveys and high-resolution swath-sonar surveys were completed on bedrock reefs on the inner shelf of northern Monterey Bay, CA, in early winter 2009, spring 2010, and summer 2010. Analysis of the sonar surveys demonstrates that during the 8 months over which the surveys were conducted, 19.6% of the study area was buried by sand while erosion resulted in the exposure of bedrock over 13.8% of the study area; the remainder underwent no change between the surveys. Substrate classifications from the benthic transect surveys correlated with classifications generated from the sonar surveys, demonstrating the capacity of high-resolution sonar surveys to detect burial of bedrock reefs by sediment. On bedrock habitat that underwent burial and exhumation, species' diversity and richness of rock-associated sessile and mobile organisms were 50–66% lower as compared to adjacent stable bedrock habitat. While intermediate levels of disturbance can increase the diversity and richness of communities, these findings demonstrate that burial and exhumation of bedrock habitat are sources of severe disturbance. We suggest that substrate dynamics must be considered when developing predictions of benthic community distributions based on sea floor imagery. These results highlight the need for predictive models of substrate dynamics and for a better understanding of how burial and exhumation shape benthic communities.

  14. VLTI-AMBER Velocity-Resolved Aperture-Synthesis Imaging of Eta Carinae with a Spectral Resolution of 12 000: Studies of the Primary Star Wind and Innermost Wind-Wind Collision Zone

    Science.gov (United States)

    Weigelt, G.; Hofmann, K.-H.; Schertl, D.; Clementel, N.; Corcoran, M. F.; Damineli, A.; de Wit, W.-J.; Grellmann, R.; Groh, J.; Guieu, S.; hide

    2016-01-01

    The mass loss from massive stars is not understood well. Eta Carinae is a unique object for studying the massive stellar wind during the luminous blue variable phase. It is also an eccentric binary with a period of 5.54 yr. The nature of both stars is uncertain, although we know from X-ray studies that there is a wind-wind collision whose properties change with orbital phase. Aims. We want to investigate the structure and kinematics of Car's primary star wind and wind-wind collision zone with a high spatial resolution of approx.6 mas (approx.14 au) and high spectral resolution of R = 12 000. Methods. Observations of Car were carried out with the ESO Very Large Telescope Interferometer (VLTI) and the AMBER instrument between approximately five and seven months before the August 2014 periastron passage. Velocity-resolved aperture-synthesis images were reconstructed from the spectrally dispersed interferograms. Interferometric studies can provide information on the binary orbit, the primary wind, and the wind collision. Results. We present velocity-resolved aperture-synthesis images reconstructed in more than 100 di erent spectral channels distributed across the Br(gamma) 2.166 micron emission line. The intensity distribution of the images strongly depends on wavelength. At wavelengths corresponding to radial velocities of approximately -140 to -376 km/s measured relative to line center, the intensity distribution has a fan-shaped structure. At the velocity of -277 km/s, the position angle of the symmetry axis of the fan is 126. The fan-shaped structure extends approximately 8.0 mas (approx.18:8 au) to the southeast and 5.8 mas (approx.13:6 au) to the northwest, measured along the symmetry axis at the 16% intensity contour. The shape of the intensity distributions suggests that the obtained images are the first direct images of the innermost wind-wind collision zone. Therefore, the observations provide velocity-dependent image structures that can be used to test three

  15. Exploring the Influence of Topographic Correction and SWIR Spectral Information Inclusion on Burnt Scars Detection From High Resolution EO Imagery: A Case Study Using ASTER imagery

    Science.gov (United States)

    Said, Yahia A.; Petropoulos, George; Srivastava, Prashant K.

    2014-05-01

    Information on burned area estimates is of key importance in environmental and ecological studies as well as in fire management including damage assessment and planning of post-fire recovery of affected areas. Earth Observation (EO) provides today the most efficient way in obtaining such information in a rapid, consistent and cost-effective manner. The present study aimed at exploring the effect of topographic correction to the burnt area delineation in conditions characteristic of a Mediterranean environment using ASTER high resolution multispectral remotely sensed imagery. A further objective was to investigate the potential added-value of the inclusion of the shortwave infrared (SWIR) bands in improving the retrievals of burned area cartography from the ASTER data. In particular the capability of the Maximum Likelihood (ML), the Support Vector Machines (SVMs) and Object-based Image Analysis (OBIA) classification techniques has been examined herein for the purposes of our study. As a case study is used a typical Mediterranean site on which a fire event occurred in Greece during the summer of 2007, for which post-fire ASTER imagery has been acquired. Our results indicated that the combination of topographic correction (ortho-rectification) with the inclusion of the SWIR bands returned the most accurate results in terms of burnt area mapping. In terms of image processing methods, OBIA showed the best results and found as the most promising approach for burned area mapping with least absolute difference from the validation polygon followed by SVM and ML. All in all, our study provides an important contribution to the understanding of the capability of high resolution imagery such as that from ASTER sensor and corroborates the usefulness particularly of the topographic correction as an image processing step when in delineating the burnt areas from such data. It also provides further evidence that use of EO technology can offer an effective practical tool for the

  16. National-scale crop type mapping and area estimation using multi-resolution remote sensing and field survey

    Science.gov (United States)

    Song, X. P.; Potapov, P.; Adusei, B.; King, L.; Khan, A.; Krylov, A.; Di Bella, C. M.; Pickens, A. H.; Stehman, S. V.; Hansen, M.

    2016-12-01

    Reliable and timely information on agricultural production is essential for ensuring world food security. Freely available medium-resolution satellite data (e.g. Landsat, Sentinel) offer the possibility of improved global agriculture monitoring. Here we develop and test a method for estimating in-season crop acreage using a probability sample of field visits and producing wall-to-wall crop type maps at national scales. The method is first illustrated for soybean cultivated area in the US for 2015. A stratified, two-stage cluster sampling design was used to collect field data to estimate national soybean area. The field-based estimate employed historical soybean extent maps from the U.S. Department of Agriculture (USDA) Cropland Data Layer to delineate and stratify U.S. soybean growing regions. The estimated 2015 U.S. soybean cultivated area based on the field sample was 341,000 km2 with a standard error of 23,000 km2. This result is 1.0% lower than USDA's 2015 June survey estimate and 1.9% higher than USDA's 2016 January estimate. Our area estimate was derived in early September, about 2 months ahead of harvest. To map soybean cover, the Landsat image archive for the year 2015 growing season was processed using an active learning approach. Overall accuracy of the soybean map was 84%. The field-based sample estimated area was then used to calibrate the map such that the soybean acreage of the map derived through pixel counting matched the sample-based area estimate. The strength of the sample-based area estimation lies in the stratified design that takes advantage of the spatially explicit cropland layers to construct the strata. The success of the mapping was built upon an automated system which transforms Landsat images into standardized time-series metrics. The developed method produces reliable and timely information on soybean area in a cost-effective way and could be implemented in an operational mode. The approach has also been applied for other crops in

  17. EarthFinder: A Precise Radial Velocity Survey Probe Mission of our Nearest Stellar Neighbors for Earth-Mass Habitable Zone Analogs Using High-Resolution UV-Vis-NIR Echelle Spectroscopy on a Space Platform

    Science.gov (United States)

    Plavchan, Peter; EarthFinder Team

    2018-01-01

    We are investigating the science case for a 1.0-1.4 meter space telescope to survey the closest, brightest FGKM main sequence stars to search for Habitable Zone (HZ) Earth analogs using the precise radial velocity (PRV) technique at a precision of 1-10 cm/s. Our baseline instrument concept uses two diffraction-limited spectrographs operating in the 0.4-1.0 microns and 1.0-2.4 microns spectral regions each with a spectral resolution of R=150,000~200,000, with the possibility of a third UV arm. Because the instrument utilizes a diffraction-limited input beam, the spectrograph would be extremely compact, less than 50 cm on a side, and illumination can be stabilized with the coupling of starlight into single mode fibers. With two octaves of wavelength coverage and a cadence unimpeded by any diurnal, seasonal, and atmospheric effects, EarthFinder will offer a unique platform for recovering stellar activity signals from starspots, plages, granulation, etc. to detect exoplanets at velocity semi-amplitudes currently not obtainable from the ground. Variable telluric absorption and emission lines may potentially preclude achieving PRV measurements at or below 10 cm/s in the visible and advantage compared to an annual ~3-6 month observing season from the ground for mitigating stellar activity and detecting the orbital periods of HZ Earth-mass analogs (e.g. ~6-months to ~2 years). Finally, we are compiling a list of ancillary science cases for the observatory, ranging from asteroseismology to the direct measurement of the expansion of the Universe.

  18. Spectral stratigraphy

    Science.gov (United States)

    Lang, Harold R.

    1991-01-01

    A new approach to stratigraphic analysis is described which uses photogeologic and spectral interpretation of multispectral remote sensing data combined with topographic information to determine the attitude, thickness, and lithology of strata exposed at the surface. The new stratigraphic procedure is illustrated by examples in the literature. The published results demonstrate the potential of spectral stratigraphy for mapping strata, determining dip and strike, measuring and correlating stratigraphic sequences, defining lithofacies, mapping biofacies, and interpreting geological structures.

  19. The HIFI spectral survey of AFGL 2591 (CHESS). I. Highly excited linear rotor molecules in the high-mass protostellar envelope

    Science.gov (United States)

    van der Wiel, M. H. D.; Pagani, L.; van der Tak, F. F. S.; Kaźmierczak, M.; Ceccarelli, C.

    2013-05-01

    Context. Linear rotor molecules such as CO, HCO+ and HCN are important probes of star-forming gas. For these species, temperatures of ≲ 50 K are sufficient to produce emission lines that are observable from the ground at (sub)millimeter wavelengths. Molecular gas in the environment of massive protostellar objects, however, is known to reach temperatures of several hundred K. To probe this, space-based far-infrared observations are required. Aims: We aim to reveal the gas energetics in the circumstellar environment of the prototypical high-mass protostellar object AFGL 2591. Methods: Rotational spectral line signatures of CO species, HCO+, CS, HCN and HNC from a 490-1240 GHz survey with Herschel/HIFI, complemented by ground-based JCMT and IRAM 30 m spectra, cover transitions in the energy range (Eup/k) between 5 K and ~ 300 K. Selected frequency settings in the highest frequency HIFI bands (up to 1850 GHz) extend this range to 750 K for 12C16O. The resolved spectral line profiles are used to separate and study various kinematic components. Observed line intensities are compared with a numerical model that calculates excitation balance and radiative transfer based on spherical geometry. Results: The line profiles show two emission components, the widest and bluest of which is attributed to an approaching outflow and the other to the envelope. We find evidence for progressively more redshifted and wider line profiles from the envelope gas with increasing energy level. This trend is qualitatively explained by residual outflow contribution picked up in the systematically decreasing beam size. Integrated line intensities for each species decrease as Eup/k increases from ≲ 50 to ~700 K. The H2 density and temperature of the outflow gas are constrained to ~105-106 cm-3 and 60-200 K. In addition, we derive a temperature between 9 and 17 K and N(H2) ~ 3 × 1021 cm-2 for a known foreground cloud seen in absorption, and N(H2) ≲ 1019 cm-2 for a second foreground component

  20. High-resolution S-wave reflection survey in a linear depression; Senjo kubochi ni okeru kobunkaino S ha hanshaho tansa

    Energy Technology Data Exchange (ETDEWEB)

    Inazaki, T [Geological Survey of Japan, Tsukuba (Japan); Sasaki, Y [Kyushu Regional Construction Bureau, Fukuoka (Japan)

    1997-10-22

    An attempt was made to apply a method combining the high-resolution S-wave reflection survey with boring to a fault survey at the Kuju town, Oita Prefecture. The investigation area has a linear depression area as small as about 600 m from east to west and about 100 m from north to south surround by mountain slopes. The boundary section with mountain peaks at the north ridge of the depression area is linear, and existence of a southward falling normal fault has been indicated. The seismic investigation has employed an artificial plank hammering method, and the derived data were processed by using the processing software, Vista for Windows. The Bin interval was 25 cm, the S-wave velocity ranged from 100 to 150 m/s, and the spatial resolution was estimated at several ten centimeters or less. The resolution is thought sufficient for assessing the fault location and displacement. The acquired depth cross sections presented distinct structural discontinuity, from which the fault locations were estimated. However, for displacements in the base bed and upper beds, the reflected waves fell into disorder at the faults, having made a detailed assessment difficult. 4 figs., 1 tab.

  1. Conjugate Etalon Spectral Imager (CESI) & Scanning Etalon Methane Mapper (SEMM), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Conjugate Etalon Spectral Imaging (CESI) concept enables the development of miniature instruments with high spectral resolution, suitable for LEO missions aboard...

  2. The B3-VLA CSS sample. VIII. New optical identifications from the Sloan Digital Sky Survey The ultraviolet-optical spectral energy distribution of the young radio sources

    Science.gov (United States)

    Fanti, C.; Fanti, R.; Zanichelli, A.; Dallacasa, D.; Stanghellini, C.

    2011-04-01

    Context. Compact steep-spectrum radio sources and giga-hertz peaked spectrum radio sources (CSS/GPS) are generally considered to be mostly young radio sources. In recent years we studied at many wavelengths a sample of these objects selected from the B3-VLA catalog: the B3-VLA CSS sample. Only ≈60% of the sources were optically identified. Aims: We aim to increase the number of optical identifications and study the properties of the host galaxies of young radio sources. Methods: We cross-correlated the CSS B3-VLA sample with the Sloan Digital Sky Survey (SDSS), DR7, and complemented the SDSS photometry with available GALEX (DR 4/5 and 6) and near-IR data from UKIRT and 2MASS. Results: We obtained new identifications and photometric redshifts for eight faint galaxies and for one quasar and two quasar candidates. Overall we have 27 galaxies with SDSS photometry in five bands, for which we derived the ultraviolet-optical spectral energy distribution (UV-O-SED). We extended our investigation to additional CSS/GPS selected from the literature. Most of the galaxies show an excess of ultra-violet (UV) radiation compared with the UV-O-SED of local radio-quiet ellipticals. We found a strong dependence of the UV excess on redshift and analyzed it assuming that it is generated either from the nucleus (hidden quasar) or from a young stellar population (YSP). We also compare the UV-O-SEDs of our CSS/GPS sources with those of a selection of large size (LSO) powerful radio sources from the literature. Conclusions: If the major process of the UV excess is caused by a YSP, our conclusion is that it is the result of the merger process that also triggered the onset of the radio source with some time delay. We do not see evidence for a major contribution from a YSP triggered by the radio sources itself. Appendices A-G are only available in electronic form at http://www.aanda.org

  3. Preliminary High Spectral-Resolution PFNDAT

    National Research Council Canada - National Science Library

    Wetmore, Alan; Ligon, David; Kvavilashvili, Ramaz

    2004-01-01

    .... The interim version of HRPFNDAT consists of a series of phase functions and extinction and scattering coefficient data for the rural, urban, and maritime haze models, water fog models, and fog oil...

  4. Liquid Scintillation High Resolution Spectral Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Grau Carles, A.; Grau Malonda, A.

    2010-08-06

    The CIEMAT/NIST and the TDCR methods in liquid scintillation counting are based on the determination of the efficiency for total counting. This paper tries to expand these methods analysing the pulse-height spectrum of radionuclides. To reach this objective we have to generalize the equations used in the model and to analyse the influence of ionization and chemical quench in both spectra and counting efficiency. We present equations to study the influence of different photomultipliers response in systems with one, two or three photomultipliers. We study the effect of the electronic noise discriminator level in both spectra and counting efficiency. The described method permits one to study problems that up to now was not possible to approach, such as the high uncertainty in the standardization of pure beta-ray emitter with low energy when we apply the TDCR method, or the discrepancies in the standardization of some electron capture radionuclides, when the CIEMAT/NIST method is applied. (Author) 107 refs.

  5. Liquid Scintillation High Resolution Spectral Analysis

    International Nuclear Information System (INIS)

    Grau Carles, A.; Grau Malonda, A.

    2010-01-01

    The CIEMAT/NIST and the TDCR methods in liquid scintillation counting are based on the determination of the efficiency for total counting. This paper tries to expand these methods analysing the pulse-height spectrum of radionuclides. To reach this objective we have to generalize the equations used in the model and to analyse the influence of ionization and chemical quench in both spectra and counting efficiency. We present equations to study the influence of different photomultipliers response in systems with one, two or three photomultipliers. We study the effect of the electronic noise discriminator level in both spectra and counting efficiency. The described method permits one to study problems that up to now was not possible to approach, such as the high uncertainty in the standardization of pure beta-ray emitter with low energy when we apply the TDCR method, or the discrepancies in the standardization of some electron capture radionuclides, when the CIEMAT/NIST method is applied. (Author) 107 refs.

  6. From Discrete Gravity Survey Data to a High-resolution Gravity Field Representation in the Nordic-Baltic Region

    DEFF Research Database (Denmark)

    Märdla, Silja; Ågren, Jonas; Strykowski, Gabriel

    2017-01-01

    The deduction of a regularly spaced gravity anomaly grid from scattered survey data is studied, addressing mainly two aspects: reduction of gravity to anomalies and subsequent interpolation by various methods. The problem is illustrated in a heterogeneous study area and contrasting test areas inc...

  7. Implications of sensor design for coral reef detection: Upscaling ground hyperspectral imagery in spatial and spectral scales

    Science.gov (United States)

    Caras, Tamir; Hedley, John; Karnieli, Arnon

    2017-12-01

    Remote sensing offers a potential tool for large scale environmental surveying and monitoring. However, remote observations of coral reefs are difficult especially due to the spatial and spectral complexity of the target compared to sensor specifications as well as the environmental implications of the water medium above. The development of sensors is driven by technological advances and the desired products. Currently, spaceborne systems are technologically limited to a choice between high spectral resolution and high spatial resolution, but not both. The current study explores the dilemma of whether future sensor design for marine monitoring should prioritise on improving their spatial or spectral resolution. To address this question, a spatially and spectrally resampled ground-level hyperspectral image was used to test two classification elements: (1) how the tradeoff between spatial and spectral resolutions affects classification; and (2) how a noise reduction by majority filter might improve classification accuracy. The studied reef, in the Gulf of Aqaba (Eilat), Israel, is heterogeneous and complex so the local substrate patches are generally finer than currently available imagery. Therefore, the tested spatial resolution was broadly divided into four scale categories from five millimeters to one meter. Spectral resolution resampling aimed to mimic currently available and forthcoming spaceborne sensors such as (1) Environmental Mapping and Analysis Program (EnMAP) that is characterized by 25 bands of 6.5 nm width; (2) VENμS with 12 narrow bands; and (3) the WorldView series with broadband multispectral resolution. Results suggest that spatial resolution should generally be prioritized for coral reef classification because the finer spatial scale tested (pixel size mind, while the focus in this study was on the technologically limited spaceborne design, aerial sensors may presently provide an opportunity to implement the suggested setup.

  8. Final Technical Report for Interagency Agreement No. DE-SC0005453 “Characterizing Aerosol Distributions, Types, and Optical and Microphysical Properties using the NASA Airborne High Spectral Resolution Lidar (HSRL) and the Research Scanning Polarimeter (RSP)”

    Energy Technology Data Exchange (ETDEWEB)

    Hostetler, Chris [NASA Langley Research Center, Hampton, VA (United States); Ferrare, Richard [NASA Langley Research Center, Hampton, VA (United States)

    2015-01-13

    Measurements of the vertical profile of atmospheric aerosols and aerosol optical and microphysical characteristics are required to: 1) determine aerosol direct and indirect radiative forcing, 2) compute radiative flux and heating rate profiles, 3) assess model simulations of aerosol distributions and types, and 4) establish the ability of surface and space-based remote sensors to measure the indirect effect. Consequently the ASR program calls for a combination of remote sensing and in situ measurements to determine aerosol properties and aerosol influences on clouds and radiation. As part of our previous DOE ASP project, we deployed the NASA Langley airborne High Spectral Resolution Lidar (HSRL) on the NASA B200 King Air aircraft during major field experiments in 2006 (MILAGRO and MaxTEX), 2007 (CHAPS), 2009 (RACORO), and 2010 (CalNex and CARES). The HSRL provided measurements of aerosol extinction (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm). These measurements were typically made in close temporal and spatial coincidence with measurements made from DOE-funded and other participating aircraft and ground sites. On the RACORO, CARES, and CalNEX missions, we also deployed the NASA Goddard Institute for Space Studies (GISS) Research Scanning Polarimeter (RSP). RSP provided intensity and degree of linear polarization over a broad spectral and angular range enabling column-average retrievals of aerosol optical and microphysical properties. Under this project, we analyzed observations and model results from RACORO, CARES, and CalNex and accomplished the following objectives. 1. Identified aerosol types, characterize the vertical distribution of the aerosol types, and partition aerosol optical depth by type, for CARES and CalNex using HSRL data as we have done for previous missions. 2. Investigated aerosol microphysical and macrophysical properties using the RSP. 3. Used the aerosol backscatter and extinction profiles measured by the HSRL

  9. Hyperspectral image classifier based on beach spectral feature

    International Nuclear Information System (INIS)

    Liang, Zhang; Lianru, Gao; Bing, Zhang

    2014-01-01

    The seashore, especially coral bank, is sensitive to human activities and environmental changes. A multispectral image, with coarse spectral resolution, is inadaptable for identify subtle spectral distinctions between various beaches. To the contrary, hyperspectral image with narrow and consecutive channels increases our capability to retrieve minor spectral features which is suit for identification and classification of surface materials on the shore. Herein, this paper used airborne hyperspectral data, in addition to ground spectral data to study the beaches in Qingdao. The image data first went through image pretreatment to deal with the disturbance of noise, radiation inconsistence and distortion. In succession, the reflection spectrum, the derivative spectrum and the spectral absorption features of the beach surface were inspected in search of diagnostic features. Hence, spectra indices specific for the unique environment of seashore were developed. According to expert decisions based on image spectrums, the beaches are ultimately classified into sand beach, rock beach, vegetation beach, mud beach, bare land and water. In situ surveying reflection spectrum from GER1500 field spectrometer validated the classification production. In conclusion, the classification approach under expert decision based on feature spectrum is proved to be feasible for beaches

  10. High-Resolution Seafloor Observations of an Active Mud Volcano Offshore SW Taiwan - Results of a Repeated Survey after Four Years

    Science.gov (United States)

    Hsu, H. H.; Chen, T. T.; Liu, C. S.; Su, C. C.; Paull, C. K.; Caress, D. W.; Gwiazda, R.; Chen, Y. H.

    2017-12-01

    Mud Volcano V (MV5) is an active submarine mud volcano sitting on top of a mud diapir ridge at water depths of 600 m in the active margin offshore of southwestern Taiwan. This cone-shape mud volcano is almost 3-km-wide, 200-m-high, with 9.5° slopes, and explosively ejects streams of mud every 1.5-3 minutes. It was first mapped in 2013 with MBARI's mapping AUV (autonomous underwater vehicle). In 2017, a repeated AUV mapping survey was conducted to see if significant bathymetric changes took place since 2013, and to investigate the fluxes of fluids that pass through diapiric structures in an active continental margin. In addition to high-resolution bathymetry (1-m-resolution), sub-bottom profiling and side-scan sonar data acquired by the AUV, and videos and samples collected by MBARI's miniROV, we also incorporate multichannel seismic reflection data and gravity core sample analyses in this study. AUV bathymetry data reveal that there are two gryphons on the eastern slope of MV5. In the 2017 survey the mapped sizes of the two side cones were 80 m wide, 35 m long, 20 m relief and 40 m wide, 40 m long, 12 m relief, respectively. Comparing the bathymetry mapped in the 2017 AUV survey with that surveyed in 2013, no obvious overall morphological changes in MV5 are detected, except around the two gryphons. In the time period between the surveys, due to venting of mud from the two gryphons, two series of flow deposits which can be up to 5 meters thick are observed along the slope in the east side of both gryphons. The center depressions of these two gryphons have increased by 1-5 meters depth in their west side. Seismic and sub-bottom profiles reveal amplitude anomalies in the sub-strata of MV5 which indicate possible fluid migration paths of mud flows from deep. The trace of mud flow from the top of MV5 to its foot can be delineated from the side-scan sonar images. On the basis of 210Pbex chronology dating method, the sedimentation rate on the surface of MV5 is very slow

  11. Dwarfs Cooler Than M: The Definition of Spectral Type L Using Discoveries form the 2-Micron All-Sky Survey (2MASS)

    Science.gov (United States)

    Kirkpatrick, J.; Reid, I.; Liebert, J.; Cutri, R.; Nelson, B.; Beichan, C.; Dahn, C.; Monet, D.; Gizis, J.; Skrutskie, M.

    2000-01-01

    Because the TiO and VO bands, which dominate the far-optical portions of late-M spectra, disappear in these cooler dwarfs, we define a new spectral class L in wich metallic oxides are replaced by metallic hydrides and neutral alkali metals as the major spectroscopic signatures.

  12. Evaluation of the U.S. Geological Survey Landsat burned area essential climate variable across the conterminous U.S. using commercial high-resolution imagery

    Science.gov (United States)

    Vanderhoof, Melanie; Brunner, Nicole M.; Beal, Yen-Ju G.; Hawbaker, Todd J.

    2017-01-01

    The U.S. Geological Survey has produced the Landsat Burned Area Essential Climate Variable (BAECV) product for the conterminous United States (CONUS), which provides wall-to-wall annual maps of burned area at 30 m resolution (1984–2015). Validation is a critical component in the generation of such remotely sensed products. Previous efforts to validate the BAECV relied on a reference dataset derived from Landsat, which was effective in evaluating the product across its timespan but did not allow for consideration of inaccuracies imposed by the Landsat sensor itself. In this effort, the BAECV was validated using 286 high-resolution images, collected from GeoEye-1, QuickBird-2, Worldview-2 and RapidEye satellites. A disproportionate sampling strategy was utilized to ensure enough burned area pixels were collected. Errors of omission and commission for burned area averaged 22 ± 4% and 48 ± 3%, respectively, across CONUS. Errors were lowest across the western U.S. The elevated error of commission relative to omission was largely driven by patterns in the Great Plains which saw low errors of omission (13 ± 13%) but high errors of commission (70 ± 5%) and potentially a region-growing function included in the BAECV algorithm. While the BAECV reliably detected agricultural fires in the Great Plains, it frequently mapped tilled areas or areas with low vegetation as burned. Landscape metrics were calculated for individual fire events to assess the influence of image resolution (2 m, 30 m and 500 m) on mapping fire heterogeneity. As the spatial detail of imagery increased, fire events were mapped in a patchier manner with greater patch and edge densities, and shape complexity, which can influence estimates of total greenhouse gas emissions and rates of vegetation recovery. The increasing number of satellites collecting high-resolution imagery and rapid improvements in the frequency with which imagery is being collected means greater opportunities to utilize these sources

  13. High resolution far-infrared survey of A section of the galactic plane. I. The nature of the sources

    International Nuclear Information System (INIS)

    Jaffe, D.T.; Stier, M.T.; Fazio, G.G.

    1982-01-01

    We have surveyed a 7.5 deg 2 portion of the galactic plane between l/sup II/ = 10 0 and l/sup II/ = 16 0 at 70 μm with a 1' beam. We present far-infrared, radio continuum, and 12 CO and 13 CO line observations of the 42 far-infrared sources in the survey region. The sources range in luminosity from 4 x 10 3 to 3 x 10 6 L/sub sun/. Most are associated with 12 CO peaks. More than half of the sources have associated H 2 O maser emission. Half have associated radio continuum emission at a limit of 100 mJy. Eight sources have radio emission at weaker levels. In a number of cases, the far-infrared source is smaller than its associated radio source. This difference can be explained in the context of the ''blister'' picture of H II regions. One group of sources emits many fewer Lyman continuum photons than expected, given the far-infrared luminosities. We examine a number of possible reasons for this and conclude that the most reasonable explanation is that clusters of early type stars rather than single stars excite the far-infrared sources. We examine the energetics in the molecular clouds surrounding the infrared sources and conclude that the sources could supply the energy to explain the observed temperature structure and velocity field in the molecular gas

  14. Next Generation UAV Based Spectral Systems for Environmental Monitoring

    Data.gov (United States)

    National Aeronautics and Space Administration — At present, UAVs used in environmental monitoring mostly collect low spectral resolution imagery, capable of retrieving canopy greenness or properties related water...

  15. The X-Shooter spectral library

    NARCIS (Netherlands)

    Chen, Y. P.; Trager, S. C.; Peletier, R. F.; Lançon, A.; Prugniel, Ph.; Koleva, M.

    2012-01-01

    We are building a new spectral library with the X-Shooter instrument on ESO's VLT: XSL, the X-Shooter Spectral Library. We present our progress in building XSL, which covers the wavelength range from the near-UV to the near-IR with a resolution of R˜10000. As of now we have collected spectra for

  16. HIGH RESOLUTION NEAR-INFRARED SURVEY OF THE PIPE NEBULA. I. A DEEP INFRARED EXTINCTION MAP OF BARNARD 59

    International Nuclear Information System (INIS)

    Roman-Zuniga, Carlos G.; Alves, Joao F.; Lada, Charles J.

    2009-01-01

    We present our analysis of a fully sampled, high resolution dust extinction map of the Barnard 59 complex in the Pipe Nebula. The map was constructed with the infrared color excess technique applied to a photometric catalog that combines data from both ground and space based observations. The map resolves for the first time the high density center of the main core in the complex, which is associated with the formation of a small cluster of stars. We found that the central core in Barnard 59 shows an unexpected lack of significant substructure consisting of only two significant fragments. Overall, the material appears to be consistent with being a single, large core with a density profile that can be well fit by a King model. A series of NH 3 pointed observations toward the high column density center of the core appear to show that the core is still thermally dominated, with subsonic non-thermal motions. The stars in the cluster could be providing feedback to support the core against collapse, but the relatively narrow radio lines suggest that an additional source of support, for example, a magnetic field, may be required to stabilize the core. Outside the central core our observations reveal the structure of peripheral cores and resolve an extended filament into a handful of significant substructures whose spacing and masses appear to be consistent with Jeans fragmentation.

  17. The Low-Resolution Spectrograph of the Hobby-Eberly Telescope. II. Observations of Quasar Candidates from the Sloan Digital Sky Survey

    International Nuclear Information System (INIS)

    Schneider, D. P.; Hill, Gary J.; Fan, X.; Ramsey, L. W.; MacQueen, P. J.; Weedman, D. W.; Booth, J. A.; Eracleous, M.; Gunn, J. E.; Lupton, R. H.

    2000-01-01

    This paper describes spectra of quasar candidates acquired during the commissioning phase of the Low-Resolution Spectrograph of the Hobby-Eberly Telescope. The objects were identified as possible quasars from multicolor image data from the Sloan Digital Sky Survey. The 10 sources had typical r' magnitudes of 19-20, except for one extremely red object with r ' ≅23. The data, obtained with exposure times between 10 and 25 minutes, reveal that the spectra of four candidates are essentially featureless and are not quasars, five are quasars with redshifts between 2.92 and 4.15 (including one broad absorption line quasar), and the red source is a very late M star or early L dwarf. (c) (c) 2000. The Astronomical Society of the Pacific

  18. Regional-Scale High Spatial Resolution Mapping of Aboveground Net Primary Productivity (ANPP from Field Survey and Landsat Data: A Case Study for the Country of Wales

    Directory of Open Access Journals (Sweden)

    Emma J. Tebbs

    2017-08-01

    Full Text Available This paper presents an alternative approach for high spatial resolution vegetation productivity mapping at a regional scale, using a combination of Normalised Difference Vegetation Index (NDVI imagery and widely distributed ground-based Above-ground Net Primary Production (ANPP estimates. Our method searches through all available single-date NDVI imagery to identify the images which give the best NDVI–ANPP relationship. The derived relationships are then used to predict ANPP values outside of field survey plots. This approach enables the use of the high spatial resolution (30 m Landsat 8 sensor, despite its low revisit frequency that is further reduced by cloud cover. This is one of few studies to investigate the NDVI–ANPP relationship across a wide range of temperate habitats and strong relationships were observed (R2 = 0.706, which increased when only grasslands were considered (R2 = 0.833. The strongest NDVI–ANPP relationships occurred during the spring “green-up” period. A reserved subset of 20% of ground-based ANPP estimates was used for validation and results showed that our method was able to estimate ANPP with a RMSE of 15–21%. This work is important because we demonstrate a general methodological framework for mapping of ANPP from local to regional scales, with the potential to be applied to any temperate ecosystems with a pronounced green up period. Our approach allows spatial extrapolation outside of field survey plots to produce a continuous surface product, useful for capturing spatial patterns and representing small-scale heterogeneity, and well-suited for modelling applications. The data requirements for implementing this approach are also discussed.

  19. HIGH-RESOLUTION 8 mm AND 1 cm POLARIZATION OF IRAS 4A FROM THE VLA NASCENT DISK AND MULTIPLICITY (VANDAM) SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Cox, Erin G.; Harris, Robert J.; Looney, Leslie W.; Segura-Cox, Dominique M. [Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Tobin, John [Leiden Observatory, Leiden University, P.O. Box 9513, 2000-RA Leiden (Netherlands); Li, Zhi-Yun [Department of Astronomy, University of Virginia, Charlottesville, VA 22903 (United States); Tychoniec, Łukasz [Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University, Słoneczna 36, PL-60-268 Poznań (Poland); Chandler, Claire J.; Perez, Laura M. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Dunham, Michael M. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Kratter, Kaitlin [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Melis, Carl [Center for Astrophysics and Space Sciences, University of California, San Diego, CA 92093 (United States); Sadavoy, Sarah I., E-mail: egcox2@illinois.edu [Max-Planck-Institut für Astronomie, D-69117 Heidelberg (Germany)

    2015-12-01

    Magnetic fields can regulate disk formation, accretion, and jet launching. Until recently, it has been difficult to obtain high-resolution observations of the magnetic fields of the youngest protostars in the critical region near the protostar. The VANDAM survey is observing all known protostars in the Perseus Molecular Cloud. Here we present the polarization data of IRAS 4A. We find that with ∼0.″2 (50 AU) resolution at λ = 8.1 and 10.3 mm, the inferred magnetic field is consistent with a circular morphology, in marked contrast with the hourglass morphology seen on larger scales. This morphology is consistent with frozen-in field lines that were dragged in by rotating material entering the infall region. The field morphology is reminiscent of rotating circumstellar material near the protostar. This is the first polarization detection of a protostar at these wavelengths. We conclude from our observations that the dust emission is optically thin with β ∼ 1.3, suggesting that millimeter-/centimeter-sized grains have grown and survived in the short lifetime of the protostar.

  20. GALACTICNUCLEUS: A high angular resolution JHKs imaging survey of the Galactic centre. I. Methodology, performance, and near-infrared extinction towards the Galactic centre

    Science.gov (United States)

    Nogueras-Lara, F.; Gallego-Calvente, A. T.; Dong, H.; Gallego-Cano, E.; Girard, J. H. V.; Hilker, M.; de Zeeuw, P. T.; Feldmeier-Krause, A.; Nishiyama, S.; Najarro, F.; Neumayer, N.; Schödel, R.

    2018-03-01

    Context. The Galactic centre (GC) is of fundamental astrophysical interest, but existing near-infrared surveys fall short covering it adequately, either in terms of angular resolution, multi-wavelength coverage, or both. Here we introduce the GALACTICNUCLEUS survey, a JHKs imaging survey of the centre of the Milky Way with a 0.2″ angular resolution. Aim. The purpose of this paper is to present the observations of Field 1 of our survey, centred approximately on SgrA* with an approximate size of 7.95' × 3.43'. We describe the observational set-up and data reduction pipeline and discuss the quality of the data. Finally, we present the analysis of the data. Methods: The data were acquired with the near-infrared camera High Acuity Wide field K-band Imager (HAWK-I) at the ESO Very Large Telescope (VLT). Short readout times in combination with the speckle holography algorithm allowed us to produce final images with a stable, Gaussian PSF (point spread function) of 0.2″ FWHM (full width at half maximum). Astrometric calibration is achieved via the VISTA Variables in the Via Lactea (VVV) survey and photometric calibration is based on the SIRIUS/Infrared Survey Facility telescope (IRSF) survey. The quality of the data is assessed by comparison between observations of the same field with different detectors of HAWK-I and at different times. Results: We reach 5σ detection limits of approximately J = 22, H = 21, and Ks = 20. The photometric uncertainties are less than 0.05 at J ≲ 20, H ≲ 17, and Ks ≲ 16. We can distinguish five stellar populations in the colour-magnitude diagrams; three of them appear to belong to foreground spiral arms, and the other two correspond to high- and low-extinction star groups at the GC. We use our data to analyse the near-infrared extinction curve and find some evidence for a possible difference between the extinction index between J - H and H - Ks. However, we conclude that it can be described very well by a power law with an index of

  1. Evidence of mud diapirism and coral colonies in the ionian sea (central mediterranean from high resolution chirp sonar survey

    Directory of Open Access Journals (Sweden)

    C. Corselli

    2006-06-01

    Full Text Available A chirp sonar survey in the Ionian Sea investigated the Calabrian margin, the Calabrian accretionary wedge, the Taranto Trench and the Apulian foreland. Shallow tectonics structures have been related to deeper ones, recognised on CROP seismic profiles. The identified echo characters have been compared with those described in the modern literature and have been related to different kinds of sediments, on the basis of core samples. Based on echo character and morphology we have recognised: 1 A widespread presence of mounds, up to 50 m high, occurring on the Apulian plateau as isolated mounds in the deepest zones (1600-800 m and in groups in the shallower ones (800-600 m; they have been interpreted as coral mounds, according to a recent discovery of living deep water coral colonies in this zone. 2 Some mud diapirs, isolated or in groups of two or three elements, widespread in the whole study area. In analogy of what has been observed on the Mediterranean Ridge, their presence suggests the activity of deep tectonic structures (thrusts and faults and a reduced thickness (or absence of Messinian evaporites in this part of the Ionian Sea.

  2. High-resolution aeromagnetic survey in the area of Arima-Takatsuki-Rokko active fault system; Arima Takatsuki Rokko katsudanso chiiki ni okeru komitsudo kuchu jiki tansa

    Energy Technology Data Exchange (ETDEWEB)

    Nakatsuka, T; Okuma, S; Morijiri, R; Makino, M [Geological Survey of Japan, Tsukuba (Japan)

    1996-10-01

    High-resolution aeromagnetic survey was conducted in December, 1995, over the area of Arima-Takatsuki-Rokko active fault system, where the 1995 Hyogo-South (Kobe) earthquake took place. Based on the surveyed data, the magnetic anomaly distribution in the Kei-Hanshin district was illustrated. Features of magnetic anomaly observed in it were discussed. Influence of artificial structures in the coastal zone of Kobe City was tried to be removed. Distinct magnetic anomaly observed in the center of Kyoto City was located at the southern part near Shijo-Karasuma. This was mainly affected by the artificial structure. A high magnetic anomaly with a long wave length was observed in the southern part of Kyoto. There was a high magnetic anomaly in an area surrounded by central cities of Nishinomiya-Toyonaka district. At the location where positive and negative magnetic anomalies were illustrated in NEDO`s map in the coastal zone of Kobe City, the anomaly pattern was clarified. The influence of artificial structure was approximated using a point dipole. The dipole was placed in each block having a magnetic anomaly. The parameter was determined by the inverse analysis, to remove the influence. Consequently, most of magnetic anomalies due to artificial structures could be removed. 6 figs.

  3. Close-range airborne Structure-from-Motion Photogrammetry for high-resolution beach morphometric surveys: Examples from an embayed rotating beach

    Science.gov (United States)

    Brunier, Guillaume; Fleury, Jules; Anthony, Edward J.; Gardel, Antoine; Dussouillez, Philippe

    2016-05-01

    The field of photogrammetry has seen significant new developments essentially related to the emergence of new computer-based applications that have fostered the growth of the workflow technique called Structure-from-Motion (SfM). Low-cost, user-friendly SfM photogrammetry offers interesting new perspectives in coastal and other fields of geomorphology requiring high-resolution topographic data. The technique enables the construction of topographic products such as digital surface models (DSMs) and orthophotographs, and combines the advantages of the reproducibility of GPS surveys and the high density and accuracy of airborne LiDAR, but at very advantageous cost compared to the latter. Three SfM-based photogrammetric experiments were conducted on the embayed beach of Montjoly in Cayenne, French Guiana, between October 2013 and 2014, in order to map morphological changes and quantify sediment budgets. The beach is affected by a process of rotation induced by the alongshore migration of mud banks from the mouths of the Amazon River that generate spatial and temporal changes in wave refraction and incident wave angles, thus generating the reversals in longshore drift that characterise this process. Sub-vertical aerial photographs of the beach were acquired from a microlight aircraft that flew alongshore at low elevation (275 m). The flight plan included several parallel flight axes with an overlap of 85% between pictures in the lengthwise direction and 50% between paths. Targets of 40 × 40 cm, georeferenced by RTK-DGPS, were placed on the beach, spaced 100 m apart. These targets served in optimizing the model and in producing georeferenced 3D products. RTK-GPS measurements of random points and cross-shore profiles were used to validate the photogrammetry results and assess their accuracy. We produced dense point clouds with 150 to 200 points/m², from which we generated DSMs and orthophotos with respective resolutions of 10 cm and 5 cm. Compared to the GPS control

  4. Pit lake lime dosing: Assessment of the performance of the treatment based on a high-spatial resolution AUV survey

    Science.gov (United States)

    Delgado, Jordi; García-Morrondo, David; Cereijo-Arango, José Luis; Muñoz-Ibáñez, Andrea; Grande-García, Elisa; Rodríguez-Cedrún, Borja; Juncosa-Rivera, Ricardo

    2016-04-01

    water quality parameters (temperature, pH, electrical conductivity, dissolved oxygen, redox, turbidity and concentration of chlorophyll) according to prescribed trajectories at constant or variable depth. In the present study, depth was fixed at 1 m below the surface of the lake and two surveys were performed in two consecutive days. Results indicate that the efficiency of lime dosing is limited and, under windy conditions (i.e. when wind-transferred energy exceeds that of the currents associated with the liming system and others present in the lake), liming tends to preferentially concentrate at the leeward side of the lake.

  5. SDSS-II SUPERNOVA SURVEY: AN ANALYSIS OF THE LARGEST SAMPLE OF TYPE IA SUPERNOVAE AND CORRELATIONS WITH HOST-GALAXY SPECTRAL PROPERTIES

    International Nuclear Information System (INIS)

    Wolf, Rachel C.; Gupta, Ravi R.; Sako, Masao; Fischer, John A.; March, Marisa C.; Fischer, Johanna-Laina; D’Andrea, Chris B.; Smith, Mathew; Kessler, Rick; Scolnic, Daniel M.; Jha, Saurabh W.; Campbell, Heather; Nichol, Robert C.; Olmstead, Matthew D.; Richmond, Michael; Schneider, Donald P.

    2016-01-01

    Using the largest single-survey sample of Type Ia supernovae (SNe Ia) to date, we study the relationship between properties of SNe Ia and those of their host galaxies, focusing primarily on correlations with Hubble residuals (HRs). Our sample consists of 345 photometrically classified or spectroscopically confirmed SNe Ia discovered as part of the SDSS-II Supernova Survey (SDSS-SNS). This analysis utilizes host-galaxy spectroscopy obtained during the SDSS-I/II spectroscopic survey and from an ancillary program on the SDSS-III Baryon Oscillation Spectroscopic Survey that obtained spectra for nearly all host galaxies of SDSS-II SN candidates. In addition, we use photometric host-galaxy properties from the SDSS-SNS data release such as host stellar mass and star formation rate. We confirm the well-known relation between HR and host-galaxy mass and find a 3.6 σ significance of a nonzero linear slope. We also recover correlations between HR and host-galaxy gas-phase metallicity and specific star formation rate as they are reported in the literature. With our large data set, we examine correlations between HR and multiple host-galaxy properties simultaneously and find no evidence of a significant correlation. We also independently analyze our spectroscopically confirmed and photometrically classified SNe Ia and comment on the significance of similar combined data sets for future surveys.

  6. THE INFRARED TELESCOPE FACILITY (IRTF) SPECTRAL LIBRARY: COOL STARS

    International Nuclear Information System (INIS)

    Rayner, John T.; Cushing, Michael C.; Vacca, William D.

    2009-01-01

    We present a 0.8-5 μm spectral library of 210 cool stars observed at a resolving power of R ≡ λ/Δλ ∼ 2000 with the medium-resolution infrared spectrograph, SpeX, at the 3.0 m NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii. The stars have well-established MK spectral classifications and are mostly restricted to near-solar metallicities. The sample not only contains the F, G, K, and M spectral types with luminosity classes between I and V, but also includes some AGB, carbon, and S stars. In contrast to some other spectral libraries, the continuum shape of the spectra is measured and preserved in the data reduction process. The spectra are absolutely flux calibrated using the Two Micron All Sky Survey photometry. Potential uses of the library include studying the physics of cool stars, classifying and studying embedded young clusters and optically obscured regions of the Galaxy, evolutionary population synthesis to study unresolved stellar populations in optically obscured regions of galaxies and synthetic photometry. The library is available in digital form from the IRTF Web site.

  7. The Infrared Telescope Facility (IRTF) Spectral Library: Cool Stars

    Science.gov (United States)

    Rayner, John T.; Cushing, Michael C.; Vacca, William D.

    2009-12-01

    We present a 0.8-5 μm spectral library of 210 cool stars observed at a resolving power of R ≡ λ/Δλ ~ 2000 with the medium-resolution infrared spectrograph, SpeX, at the 3.0 m NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii. The stars have well-established MK spectral classifications and are mostly restricted to near-solar metallicities. The sample not only contains the F, G, K, and M spectral types with luminosity classes between I and V, but also includes some AGB, carbon, and S stars. In contrast to some other spectral libraries, the continuum shape of the spectra is measured and preserved in the data reduction process. The spectra are absolutely flux calibrated using the Two Micron All Sky Survey photometry. Potential uses of the library include studying the physics of cool stars, classifying and studying embedded young clusters and optically obscured regions of the Galaxy, evolutionary population synthesis to study unresolved stellar populations in optically obscured regions of galaxies and synthetic photometry. The library is available in digital form from the IRTF Web site.

  8. Sea Level History in 3D: Early results of an ultra-high resolution MCS survey across IODP Expedition 313 drillsites

    Science.gov (United States)

    Mountain, G. S.; Kucuk, H. M.; Nedimovic, M. R.; Austin, J. A., Jr.; Fulthorpe, C.; Newton, A.; Baldwin, K.; Johnson, C.; Stanley, J. N.; Bhatnagar, T.

    2015-12-01

    Although globally averaged sea level is rising at roughly 3 mm/yr (and is accelerating), rates of local sea-level change measured at coastlines may differ from this number by a factor of two or more; at some locations, sea level may even be falling. This is due to local processes that can match or even reverse the global trend, making it clear that reliable predictions of future impacts of sea-level rise require a firm understanding of processes at the local level. The history of local sea-level change and shoreline response is contained in the geologic record of shallow-water sediments. We report on a continuing study of sea-level history in sediments at the New Jersey continental margin, where compaction and glacial isostatic adjustment are currently adding 2 mm/yr to the globally averaged rise. We collected 570 sq km of ultra-high resolution 3D MCS data aboard the R/V Langseth in June-July 2015; innovative recording and preliminary results are described by Nedimovic et al. in this same session. The goal was to provide regional context to coring and logging at IODP Exp 313 sites 27-29 that were drilled 750 m into the New Jersey shelf in 2009. These sites recovered a nearly continuous record of post-Eocene sediments from non-marine soils, estuaries, shoreface, delta front, pro-delta and open marine settings. Existing seismic data are good but are 2D high-resolution profiles at line spacings too wide to enable mapping of key nearshore features. The Langseth 3D survey used shallow towing of a tuned air gun array to preserve high frequencies, and twenty-four 50-m PCables each 12.5 apart provided 6.25 x 3.125 m common-midpoint bins along seventy-seven 50-km sail lines. With this especially dense spatial resolution of a pre-stack time migrated volume we expect to map rivers, incised valleys, barrier islands, inlets and bays, pro-delta clinoforms, tidal deltas, sequence boundaries, debris flow aprons, and more. Seismic attributes linked to sedimentary facies and

  9. Intensity Conserving Spectral Fitting

    Science.gov (United States)

    Klimchuk, J. A.; Patsourakos, S.; Tripathi, D.

    2015-01-01

    The detailed shapes of spectral line profiles provide valuable information about the emitting plasma, especially when the plasma contains an unresolved mixture of velocities, temperatures, and densities. As a result of finite spectral resolution, the intensity measured by a spectrometer is the average intensity across a wavelength bin of non-zero size. It is assigned to the wavelength position at the center of the bin. However, the actual intensity at that discrete position will be different if the profile is curved, as it invariably is. Standard fitting routines (spline, Gaussian, etc.) do not account for this difference, and this can result in significant errors when making sensitive measurements. Detection of asymmetries in solar coronal emission lines is one example. Removal of line blends is another. We have developed an iterative procedure that corrects for this effect. It can be used with any fitting function, but we employ a cubic spline in a new analysis routine called Intensity Conserving Spline Interpolation (ICSI). As the name implies, it conserves the observed intensity within each wavelength bin, which ordinary fits do not. Given the rapid convergence, speed of computation, and ease of use, we suggest that ICSI be made a standard component of the processing pipeline for spectroscopic data.

  10. Spectral Imaging by Upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2011-01-01

    We present a method to obtain spectrally resolved images using upconversion. By this method an image is spectrally shifted from one spectral region to another wavelength. Since the process is spectrally sensitive it allows for a tailored spectral response. We believe this will allow standard...... silicon based cameras designed for visible/near infrared radiation to be used for spectral images in the mid infrared. This can lead to much lower costs for such imaging devices, and a better performance....

  11. Spectral quality requirements for effluent identification

    Science.gov (United States)

    Czerwinski, R. N.; Seeley, J. A.; Wack, E. C.

    2005-11-01

    We consider the problem of remotely identifying gaseous materials using passive sensing of long-wave infrared (LWIR) spectral features at hyperspectral resolution. Gaseous materials are distinguishable in the LWIR because of their unique spectral fingerprints. A sensor degraded in capability by noise or limited spectral resolution, however, may be unable to positively identify contaminants, especially if they are present in low concentrations or if the spectral library used for comparisons includes materials with similar spectral signatures. This paper will quantify the relative importance of these parameters and express the relationships between them in a functional form which can be used as a rule of thumb in sensor design or in assessing sensor capability for a specific task. This paper describes the simulation of remote sensing datacontaining a gas cloud.In each simulation, the spectra are degraded in spectral resolution and through the addition of noise to simulate spectra collected by sensors of varying design and capability. We form a trade space by systematically varying the number of sensor spectral channels and signal-to-noise ratio over a range of values. For each scenario, we evaluate the capability of the sensor for gas identification by computing the ratio of the F-statistic for the truth gas tothe same statistic computed over the rest of the library.The effect of the scope of the library is investigated as well, by computing statistics on the variability of the identification capability as the library composition is varied randomly.

  12. "Calibration" system for spectral measurements and its experimental results

    Science.gov (United States)

    Bruchkouskaya, Sviatlana I.; Katkovsky, Leonid V.; Belyaev, Boris I.; Malyshev, Vladislav B.

    2017-04-01

    "Calibration" system has been developed at A. N. Sevchenko Research Institute of Applied Physical Problems of the Belarusian State University. It was designed for measuring the characteristics of spectral reflectance of all types of natural surfaces (test sites) in ground conditions or on board of aircraft carriers and has the following components: - Photospectroradiometr (PhSR) of high resolution with a range of 400-900 nm, equipped with a digital time-lapse video system; - Two-channel modular spectroradiometer (TMS) with a range of 400-900 nm, designed for simultaneous measurements of reflected light brightness of the underlying surface and the incident radiation from the upper hemisphere; - Two portable spectroradiometers (PSR-700 and PSR-1300) with a spectral range 800-1500 nm; 1200-2500 nm; - Scanning solar spectropolarimeter (SSP-600) with a range of 350-950 nm for measurements of direct sunlight and scattered by the atmosphere at different angles; "Calibration" system provides spectral resolution of 5.2 nm in a range of 400-900 nm, 10 nm in a range of 800-1500 nm and 15 nm in a range of 1200-2500 nm. Measurements of the optical characteristics of solar radiation (for determining parameters of the atmosphere) and that of underlying surface are synchronous. There is also a set of special nozzles for measurements of spectral brightness coefficients, polarization characteristics and spectral albedo. Spectra and images are geotagged to the navigation data (time, GPS). For the measurements of spectral reflection dependencies within "Monitoring-SG" framework expeditions to the Kuril Islands, Kursk aerospace test site and Kamchatka Peninsula were conducted in 2015 and 2016. The spectra of different underlying surfaces have been obtained: soils, plants and water objects, sedimentary and volcanic rocks. These surveys are a valuable material for further researches and selection of test facilities for flight calibration of space imaging systems. Information obtained

  13. Spectral Decomposition Algorithm (SDA)

    Data.gov (United States)

    National Aeronautics and Space Administration — Spectral Decomposition Algorithm (SDA) is an unsupervised feature extraction technique similar to PCA that was developed to better distinguish spectral features in...

  14. Coastal Sediment Distribution Patterns Following Category 5 Hurricanes (Irma and Maria): Pre and Post Hurricane High Resolution Multibeam Surveys of Eastern St. John, US Virgin Islands

    Science.gov (United States)

    Browning, T. N.; Sawyer, D. E.; Russell, P.

    2017-12-01

    In August of 2017 we collected high resolution multibeam data of the seafloor in a large embayment in eastern St. John, US Virgin Islands (USVI). One month later, the eyewall of Category 5 Hurricane Irma directly hit St. John as one of the largest hurricanes on record in the Atlantic Ocean. A week later, Category 5 Hurricane Maria passed over St. John. While the full extent of the impacts are still being assessed, the island experienced a severe loss of vegetation, infrastructure, buildings, roads, and boats. We mobilized less than two months afterward to conduct a repeat survey of the same area on St. John. We then compared these data to document and quantify the sediment influx and movement that occurred in coastal embayments as a result of Hurricanes Irma and Maria. The preliminary result of the intense rain, wind, and storm surge likely yields an event deposit that can be mapped and volumetrically quantified in the bays of eastern St. John. The results of this study allow for a detailed understanding of the post-hurricane pulse of sediment that enters the marine environment, the sediment flux seaward, and the morphological changes to the bay floor.

  15. PSYM-WIDE: A Survey for Large-separation Planetary-mass Companions to Late Spectral Type Members of Young Moving Groups

    Science.gov (United States)

    Naud, Marie-Eve; Artigau, Étienne; Doyon, René; Malo, Lison; Gagné, Jonathan; Lafrenière, David; Wolf, Christian; Magnier, Eugene A.

    2017-09-01

    We present the results of a direct imaging survey for very large separation (>100 au), low-mass companions around 95 nearby young K5-L5 stars and brown dwarfs. They are high-likelihood candidates or confirmed members of the young (≲150 Myr) β Pictoris and AB Doradus moving groups (ABDMG) and the TW Hya, Tucana-Horologium, Columba, Carina, and Argus associations. Images in I\\prime and z\\prime filters were obtained with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South to search for companions down to an apparent magnitude of z\\prime ˜ 22-24 at separations ≳20″ from the targets and in the remainder of the wide 5.‧5 × 5.‧5 GMOS field of view. This allowed us to probe the most distant region where planetary-mass companions could be gravitationally bound to the targets. This region was left largely unstudied by past high-contrast imaging surveys, which probed much closer-in separations. This survey led to the discovery of a planetary-mass (9-13 {M}{Jup}) companion at 2000 au from the M3V star GU Psc, a highly probable member of ABDMG. No other substellar companions were identified. These results allowed us to constrain the frequency of distant planetary-mass companions (5-13 {M}{Jup}) to {0.84}-0.66+6.73% (95% confidence) at semimajor axes between 500 and 5000 au around young K5-L5 stars and brown dwarfs. This is consistent with other studies suggesting that gravitationally bound planetary-mass companions at wide separations from low-mass stars are relatively rare.

  16. High-resolution digital elevation model of Mount St. Helens crater and upper North Fork Toutle River basin, Washington, based on an airborne lidar survey of September 2009

    Science.gov (United States)

    Mosbrucker, Adam

    2014-01-01

    The lateral blast, debris avalanche, and lahars of the May 18th, 1980, eruption of Mount St. Helens, Washington, dramatically altered the surrounding landscape. Lava domes were extruded during the subsequent eruptive periods of 1980–1986 and 2004–2008. More than three decades after the emplacement of the 1980 debris avalanche, high sediment production persists in the North Fork Toutle River basin, which drains the northern flank of the volcano. Because this sediment increases the risk of flooding to downstream communities on the Toutle and Cowlitz Rivers, the U.S. Army Corps of Engineers (USACE), under the direction of Congress to maintain an authorized level of flood protection, built a sediment retention structure on the North Fork Toutle River in 1989 to help reduce this risk and to prevent sediment from clogging the shipping channel of the Columbia River. From September 16–20, 2009, Watershed Sciences, Inc., under contract to USACE, collected high-precision airborne lidar (light detection and ranging) data that cover 214 square kilometers (83 square miles) of Mount St. Helens and the upper North Fork Toutle River basin from the sediment retention structure to the volcano's crater. These data provide a digital dataset of the ground surface, including beneath forest cover. Such remotely sensed data can be used to develop sediment budgets and models of sediment erosion, transport, and deposition. The U.S. Geological Survey (USGS) used these lidar data to develop digital elevation models (DEMs) of the study area. DEMs are fundamental to monitoring natural hazards and studying volcanic landforms, fluvial and glacial geomorphology, and surface geology. Watershed Sciences, Inc., provided files in the LASer (LAS) format containing laser returns that had been filtered, classified, and georeferenced. The USGS produced a hydro-flattened DEM from ground-classified points at Castle, Coldwater, and Spirit Lakes. Final results averaged about five laser last

  17. High-resolution digital elevation model of lower Cowlitz and Toutle Rivers, adjacent to Mount St. Helens, Washington, based on an airborne lidar survey of October 2007

    Science.gov (United States)

    Mosbrucker, Adam

    2015-01-01

    The lateral blast, debris avalanche, and lahars of the May 18th, 1980, eruption of Mount St. Helens, Washington, dramatically altered the surrounding landscape. Lava domes were extruded during the subsequent eruptive periods of 1980–1986 and 2004–2008. More than three decades after the emplacement of the 1980 debris avalanche, high sediment production persists in the Toutle River basin, which drains the northern and western flanks of the volcano. Because this sediment increases the risk of flooding to downstream communities on the Toutle and lower Cowlitz Rivers, the U.S. Army Corps of Engineers (USACE), under the direction of Congress to maintain an authorized level of flood protection, continues to monitor and mitigate excess sediment in North and South Fork Toutle River basins to help reduce this risk and to prevent sediment from clogging the shipping channel of the Columbia River. From October 22–27, 2007, Watershed Sciences, Inc., under contract to USACE, collected high-precision airborne lidar (light detection and ranging) data that cover 273 square kilometers (105 square miles) of lower Cowlitz and Toutle River tributaries from the Columbia River at Kelso, Washington, to upper North Fork Toutle River (below the volcano's edifice), including lower South Fork Toutle River. These data provide a digital dataset of the ground surface, including beneath forest cover. Such remotely sensed data can be used to develop sediment budgets and models of sediment erosion, transport, and deposition. The U.S. Geological Survey (USGS) used these lidar data to develop digital elevation models (DEMs) of the study area. DEMs are fundamental to monitoring natural hazards and studying volcanic landforms, fluvial and glacial geomorphology, and surface geology. Watershed Sciences, Inc., provided files in the LASer (LAS) format containing laser returns that had been filtered, classified, and georeferenced. The USGS produced a hydro-flattened DEM from ground-classified points at

  18. High-resolution seismic survey for the characterization of planned PIER-ICDP fluid-monitoring sites in the Eger Rift zone

    Science.gov (United States)

    Simon, H.; Buske, S.

    2017-12-01

    The Eger Rift zone (Czech Republic) is a intra-continental non-volcanic region and is characterized by outstanding geodynamic activities, which result in earthquake swarms and significant CO2 emanations. Because fluid-induced stress can trigger earthquake swarms, both natural phenomena are probably related to each other. The epicentres of the earthquake swarms cluster at the northern edge of the Cheb Basin. Although the location of the cluster coincides with the major Mariánské-Lázně Fault Zone (MLFZ) the strike of the focal plane indicates another fault zone, the N-S trending Počátky-Plesná Zone (PPZ). Isotopic analysis of the CO2-rich fluids revealed a significant portion of upper mantle derived components, hence a magmatic fluid source in the upper mantle was postulated. Because of these phenomena, the Eger Rift area is a unique site for interdisciplinary drilling programs to study the fluid-earthquake interaction. The ICDP project PIER (Probing of Intra-continental magmatic activity: drilling the Eger Rift) will set up an observatory, consisting of five monitoring boreholes. In preparation for the drilling, the goal of the seismic survey is the characterization of the projected fluid-monitoring drill site at the CO2 degassing mofette field near Hartoušov. This will be achieved by a 6 km long profile with dense source and receiver spacing. The W-E trending profile will cross the proposed drill site and the surface traces of MLFZ and PPZ. The outcome of the seismic survey will be a high-resolution structural image of potential reflectors related to these fault zones. This will be achieved by the application of advanced pre-stack depth migration methods and a detailed P-wave velocity distribution of the area obtained from first arrival tomography. During interpretation of the seismic data, a geoelectrical resistivity model, acquired along the same profile line, will provide important constraints, especially with respect to fluid pathways.

  19. Proton and electron impact on molecular and atomic oxygen: I. High resolution fluorescence spectra in the visible and VUV spectral range and emission cross-sections for dissociative ionisation and excitation of O2

    International Nuclear Information System (INIS)

    Wilhelmi, O.; Schartner, K.H.

    2000-01-01

    For pt.II see ibid., vol.11, p.45-58, 2000. Molecular oxygen O 2 was dissociated in collisions with protons and electrons in the intermediate velocity range (p + -energies: 17-800 keV, e - -energies: 0.2-2 keV). Fluorescence from excited atomic and singly ionised fragments and from singly ionised molecules was detected in the VUV and in the visible and near UV spectral range. Highly resolved spectra are presented for the VUV (46-131 nm) and the near UV/visible (340-605 nm) spectral range. Absolute emission cross-sections have been determined for dissociative ionisation and excitation leading to fluorescence in the VUV. Results are compared with published data. (orig.)

  20. True resolution enhancement for optical spectroscopy

    Science.gov (United States)

    Cooper, Justin T.; Oleske, Jeffrey B.

    2018-02-01

    Resolving spectrally adjacent peaks is important for techniques, such as tracking small shifts in Raman or fluorescence spectra, quantifying pharmaceutical polymorph ratios, or molecular orientation studies. Thus, suitable spectral resolution is a vital consideration when designing most spectroscopic systems. Most parameters that influence spectral resolution are fixed for a given system (spectrometer length, grating groove density, excitation source, CCD pixel size, etc.). Inflexible systems are non-problematic if the spectrometer is dedicated for a single purpose; however, these specifications cannot be optimized for different applications with wider range resolution requirements. Data processing techniques, including peak fitting, partial least squares, or principal component analysis, are typically used to achieve sub-optical resolution information. These techniques can be plagued by spectral artifacts introduced by post-processing as well as the subjective implementation of statistical parameters. TruRes™, from Andor Technology, uses an innovative optical means to greatly improve and expand the range of spectral resolutions accessible on a single setup. True spectral resolution enhancement of >30% is achieved without mathematical spectral alteration, dataprocessing, or spectrometer component changes. Discreet characteristic spectral lines from Laser-Induced Breakdown Spectroscopy (LIBS) and atomic calibration sources are now fully resolved from spectrally-adjacent peaks under otherwise identical configuration. TruRes™ has added advantage of increasing the spectral resolution without sacrificing bandpass. Using TruRes™ the Kymera 328i resolution can approach that of a 500 mm focal spectrometer. Furthermore, the bandpass of a 500 mm spectrograph with would be 50% narrower than the Kymera 328i with all other spectrometer components constant. However, the Kymera 328i with TruRes™ is able to preserve a 50% wider bandpass.

  1. Extracting attosecond delays from spectrally overlapping interferograms

    Science.gov (United States)

    Jordan, Inga; Wörner, Hans Jakob

    2018-02-01

    Attosecond interferometry is becoming an increasingly popular technique for measuring the dynamics of photoionization in real time. Whereas early measurements focused on atomic systems with very simple photoelectron spectra, the technique is now being applied to more complex systems including isolated molecules and solids. The increase in complexity translates into an augmented spectral congestion, unavoidably resulting in spectral overlap in attosecond interferograms. Here, we discuss currently used methods for phase retrieval and introduce two new approaches for determining attosecond photoemission delays from spectrally overlapping photoelectron spectra. We show that the previously used technique, consisting in the spectral integration of the areas of interest, does in general not provide reliable results. Our methods resolve this problem, thereby opening the technique of attosecond interferometry to complex systems and fully exploiting its specific advantages in terms of spectral resolution compared to attosecond streaking.

  2. Numerical modeling to assess the sensitivity and resolution of long-electrode electrical resistance tomography (LEERT) surveys to monitor CO2 migration, Phase 1B area

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, Abelardo L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2010-05-18

    This document describes the results of a numerical modeling study that evaluated whether LEERT could be used successfully to monitor CO2 distribution in the Weyburn- Midale reservoir, Phase 1B area. The magnitude of electrical resistivity changes and the technique’s resolution depend on many site-specific factors including well separation distances, casing lengths, reservoir depth, thickness, and composition, and the effect of CO2 on the electrical properties of the reservoir. Phase 1B-specific numerical modeling of the electrical response to CO2 injection has been performed to assess sensitivity and resolution of the electrical surveys.

  3. Development of a high resolution cylindrical crystal spectrometer for line shape and spectral diagnostics of x-rays emitted from - hot - plasmas. Final report, June 1, 1976-December 31, 1983

    International Nuclear Information System (INIS)

    Kaellne, E.G.

    1984-01-01

    The development, installation and evaluation of a high resolution X-ray spectroscopic diagnostics are reported. The approach has been to optimize spectrometer throughput to enable single shot plasma diagnostics with good time resolution and to ensure sufficient energy resolution to allow line profile analysis. These goals have been achieved using a new X-ray geometry combined with a new position sensitive X-ray detector. These diagnostics have been used at Alcator C to detect X-ray emission of highly ionized impurity elements as well as argon seed elements specially introduced into the plasma for this diagnostic. Temporally resolved ion temperature profiles have been obtained from the recorded X-ray spectra simultaneously with other plasma parameters such as electron temperature, ionization temperature and ionization stage distribution. Radial profiles have also been measured. The developed X-ray diagnostics thus serve as a major multiparameter probe of the central core of the plasma with complementary informtion on radial profiles

  4. Spectral and spatial resolution properties of photon counting X-ray detectors like the Medipix-Detector; Spektrale und bildgebende Eigenschaften photonenzaehlender Roentgendetektoren am Beispiel des Medipix-Detektors

    Energy Technology Data Exchange (ETDEWEB)

    Korn, A.

    2007-05-14

    The Medipix detector is a hybrid photon counting X-ray detector, consisting of an ASIC and a semiconducting layer as the sensor. This makes the Medipix a direct converting detector. A special feature of the Medipix is a signal processing circuit in every single pixel. This circuit amplifies the input signal triggered by a photon and then transforms the pulse into a digital signal. This early stage digitalisation is one of the main advantages of the detector, since no dark currents are integrated into the signal. Furthermore, the energy information of each single photon is partly preserved. The high number of pixels lends the detector a wide dynamic range, starting from single counts up to a rate of 1010 photons per cm2 and second. Apart from the many advantages, there are still some problems with the detector. Some effects lead to a deterioration of the energy resolution as well as the spatial resolution. The main reasons for this are two effects occuring in the detector, charge sharing and backscattering inside the detector. This study investigates the influence of those two effects on both the energy and spatial resolution. The physical causes of these effects are delineated and their impact on the detector output is examined. In contrast to high energy photon detectors, the repulsion of the charge carriers drifting inside the sensor must not be neglected in a detailed model of X-ray detectors with an energy range of 5 keV-200 keV. For the simulation of the Medipix using Monte Carlo simulations, the software ROSI was augmented. The added features allow a detailed simulation of the charge distribution, using the relevant physical effects that alter the distribution width during the drift towards the sensor electrodes as well further influences on the detector output, including electronical noise, threshold noise or the geometry of the detector. The measured energy and spatial resolution of several different models of Medipix is compared to the simulated

  5. Power spectral estimation of high-harmonics in echoes of wall resonances to improve resolution in non-invasive measurements of wall mechanical properties in rubber tube and ex-vivo artery.

    Science.gov (United States)

    Bazan, I; Ramos, A; Balay, G; Negreira, C

    2018-07-01

    The aim of this work is to develop a new type of ultrasonic analysis of the mechanical properties of an arterial wall with improved resolution, and to confirm its feasibility under laboratory conditions. it is expected that this would facilitate a non-invasive path for accurate predictive diagnosis that enables an early detection & therapy of vascular pathologies. In particular, the objective is to detect and quantify the small elasticity changes (in Young's modulus E) of arterial walls, which precede pathology. A submicron axial resolution is required for this analysis, as the periodic widening of the wall (under oscillatory arterial pressure) varies between ±10 and 20 μm. This high resolution represents less than 1% of the parietal thickness (e.g., harmonics of the wall internal resonance f 0 . This was attained via the implementation of an autoregressive parametric algorithm that accurately detects parietal echo-dynamics during a heartbeat. Thus, it was possible to measure the punctual elasticity of the wall, with a higher resolution (> an order of magnitude) compared to conventional approaches. The resolution of a typical ultrasonic image is limited to several hundred microns, and thus, such small changes are undetected. The proposed procedure provides a non-invasive and direct measure of elasticity by doing an estimation of changes in the Nf 0 harmonics and wall thickness with a resolution of 0.1%, for first time. The results obtained by using the classic temporal cross-correlation method (TCC) were compared to those obtained with the new procedure. The latter allowed the evaluation of alterations in the elastic properties of arterial walls that are 30 times smaller than those being detectable with TCC; in fact, the depth resolution of the TCC approach is limited to ≈20 μm for typical SNRs. These values were calculated based on echoes obtained using a reference pattern (rubber tube). The application of the proposed procedure was also confirmed via

  6. Spectral gamuts and spectral gamut mapping

    Science.gov (United States)

    Rosen, Mitchell R.; Derhak, Maxim W.

    2006-01-01

    All imaging devices have two gamuts: the stimulus gamut and the response gamut. The response gamut of a print engine is typically described in CIE colorimetry units, a system derived to quantify human color response. More fundamental than colorimetric gamuts are spectral gamuts, based on radiance, reflectance or transmittance units. Spectral gamuts depend on the physics of light or on how materials interact with light and do not involve the human's photoreceptor integration or brain processing. Methods for visualizing a spectral gamut raise challenges as do considerations of how to utilize such a data-set for producing superior color reproductions. Recent work has described a transformation of spectra reduced to 6-dimensions called LabPQR. LabPQR was designed as a hybrid space with three explicit colorimetric axes and three additional spectral reconstruction axes. In this paper spectral gamuts are discussed making use of LabPQR. Also, spectral gamut mapping is considered in light of the colorimetric-spectral duality of the LabPQR space.

  7. The X-shooter Spectral Library and Carbon stars

    NARCIS (Netherlands)

    Gonneau, A.; Lançon, A.; Trager, S. C.; Chen, Y.; Peletier, R.; Aringer, B.; Nowotny, W.; Cambrésy, L.; Martins, F.; Nuss, E.; Palacios, A.

    2013-01-01

    Until recently, most empirical stellar spectral libraries were limited to a certain wavelength range or combined data from different stars, taken by different instruments of which some have low spectral resolution, limiting for instance our ability to analyze galaxies jointly in the ultraviolet, the

  8. Prospects for Measuring Abundances of >20 Elements with Low-resolution Stellar Spectra

    Energy Technology Data Exchange (ETDEWEB)

    Ting Yuan-Sen; Conroy, Charlie; Cargile, Phillip [Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Rix, Hans-Walter [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

    2017-07-01

    Understanding the evolution of the Milky Way calls for the precise abundance determination of many elements in many stars. A common perception is that deriving more than a few elemental abundances ([Fe/H], [ α /Fe], perhaps [C/H], [N/H]) requires medium-to-high spectral resolution, R ≳ 10,000, mostly to overcome the effects of line blending. In a recent work, we presented an efficient and practical way to model the full stellar spectrum, even when fitting a large number of stellar labels simultaneously. In this paper, we quantify to what precision the abundances of many different elements can be recovered, as a function of spectroscopic resolution and wavelength range. In the limit of perfect spectral models and spectral normalization, we show that the precision of elemental abundances is nearly independent of resolution, for a fixed exposure time and number of detector pixels; low-resolution spectra simply afford much higher S/N per pixel and generally larger wavelength range in a single setting. We also show that estimates of most stellar labels are not strongly correlated with one another once R ≳ 1000. Modest errors in the line-spread function, as well as small radial velocity errors, do not affect these conclusions, and data-driven models indicate that spectral (continuum) normalization can be achieved well enough in practice. These results, to be confirmed with an analysis of observed low-resolution data, open up new possibilities for the design of large spectroscopic stellar surveys and for the reanalysis of archival low-resolution data sets.

  9. USGS Spectral Library Version 7

    Science.gov (United States)

    Kokaly, Raymond F.; Clark, Roger N.; Swayze, Gregg A.; Livo, K. Eric; Hoefen, Todd M.; Pearson, Neil C.; Wise, Richard A.; Benzel, William M.; Lowers, Heather A.; Driscoll, Rhonda L.; Klein, Anna J.

    2017-04-10

    We have assembled a library of spectra measured with laboratory, field, and airborne spectrometers. The instruments used cover wavelengths from the ultraviolet to the far infrared (0.2 to 200 microns [μm]). Laboratory samples of specific minerals, plants, chemical compounds, and manmade materials were measured. In many cases, samples were purified, so that unique spectral features of a material can be related to its chemical structure. These spectro-chemical links are important for interpreting remotely sensed data collected in the field or from an aircraft or spacecraft. This library also contains physically constructed as well as mathematically computed mixtures. Four different spectrometer types were used to measure spectra in the library: (1) Beckman™ 5270 covering the spectral range 0.2 to 3 µm, (2) standard, high resolution (hi-res), and high-resolution Next Generation (hi-resNG) models of Analytical Spectral Devices (ASD) field portable spectrometers covering the range from 0.35 to 2.5 µm, (3) Nicolet™ Fourier Transform Infra-Red (FTIR) interferometer spectrometers covering the range from about 1.12 to 216 µm, and (4) the NASA Airborne Visible/Infra-Red Imaging Spectrometer AVIRIS, covering the range 0.37 to 2.5 µm. Measurements of rocks, soils, and natural mixtures of minerals were made in laboratory and field settings. Spectra of plant components and vegetation plots, comprising many plant types and species with varying backgrounds, are also in this library. Measurements by airborne spectrometers are included for forested vegetation plots, in which the trees are too tall for measurement by a field spectrometer. This report describes the instruments used, the organization of materials into chapters, metadata descriptions of spectra and samples, and possible artifacts in the spectral measurements. To facilitate greater application of the spectra, the library has also been convolved to selected spectrometer and imaging spectrometers sampling and

  10. High resolution mid-infrared spectroscopy based on frequency upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Hu, Qi; Tidemand-Lichtenberg, Peter

    2013-01-01

    signals can be analyzed. The obtainable frequency resolution is usually in the nm range where sub nm resolution is preferred in many applications, like gas spectroscopy. In this work we demonstrate how to obtain sub nm resolution when using upconversion. In the presented realization one object point...... high resolution spectral performance by observing emission from hot water vapor in a butane gas burner....

  11. A fast, noniterative approach for accelerated high-temporal resolution cine-CMR using dynamically interleaved streak removal in the power-spectral encoded domain with low-pass filtering (DISPEL) and modulo-prime spokes (MoPS).

    Science.gov (United States)

    Kawaji, Keigo; Patel, Mita B; Cantrell, Charles G; Tanaka, Akiko; Marino, Marco; Tamura, Satoshi; Wang, Hui; Wang, Yi; Carroll, Timothy J; Ota, Takeyoshi; Patel, Amit R

    2017-07-01

    To introduce a pair of accelerated non-Cartesian acquisition principles that when combined, exploit the periodicity of k-space acquisition, and thereby enable acquisition of high-temporal cine Cardiac Magnetic Resonance (CMR). The mathematical formulation of a noniterative, undersampled non-Cartesian cine acquisition and reconstruction is presented. First, a low-pass filtering step that exploits streaking artifact redundancy is provided (i.e., Dynamically Interleaved Streak removal in the Power-spectrum Encoded domain with Low-pass filtering [DISPEL]). Next, an effective radial acquisition for the DISPEL approach that exploits the property of prime numbers is described (i.e., Modulo-Prime Spoke [MoPS]). Both DISPEL and MoPS are examined using numerical simulation of a digital heart phantom to show that high-temporal cine-CMR is feasible without removing physiologic motion vs aperiodic interleaving using Golden Angles. The combined high-temporal cine approach is next examined in 11 healthy subjects for a time-volume curve assessment of left ventricular systolic and diastolic performance vs conventional Cartesian cine-CMR reference. The DISPEL method was first shown using simulation under different streak cycles to allow separation of undersampled radial streaking artifacts from physiologic motion with a sufficiently frequent streak-cycle interval. Radial interleaving with MoPS is next shown to allow interleaves with pseudo-Golden-Angle variants, and be more compatible with DISPEL against irrational and nonperiodic rotation angles, including the Golden-Angle-derived rotations. In the in vivo data, the proposed method showed no statistical difference in the systolic performance, while diastolic parameters sensitive to the cine's temporal resolution were statistically significant (P cine). We demonstrate a high-temporal resolution cine-CMR using DISPEL and MoPS, whose streaking artifact was separated from physiologic motion. © 2017 American Association of Physicists

  12. Estuarine Bathymetric Digital Elevation Models (30 meter and 3 arc second resolution) Derived From Source Hydrographic Survey Soundings Collected by NOAA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These Bathymetric Digital Elevation Models (DEM) were generated from original point soundings collected during hydrographic surveys conducted by the National Ocean...

  13. Introduction to spectral theory

    CERN Document Server

    Levitan, B M

    1975-01-01

    This monograph is devoted to the spectral theory of the Sturm- Liouville operator and to the spectral theory of the Dirac system. In addition, some results are given for nth order ordinary differential operators. Those parts of this book which concern nth order operators can serve as simply an introduction to this domain, which at the present time has already had time to become very broad. For the convenience of the reader who is not familar with abstract spectral theory, the authors have inserted a chapter (Chapter 13) in which they discuss this theory, concisely and in the main without proofs, and indicate various connections with the spectral theory of differential operators.

  14. Carbon Transfers and Emissions Following Harvest and Pile Burning in Coastal Douglas-fir Forests Determined from Analysis of High-Resolution UAV Imagery and Point Clouds and from Field Surveys.

    Science.gov (United States)

    Trofymow, J. A.; Gougeon, F.; Kelley, J. W.

    2017-12-01

    Forest carbon (C) models require knowledge on C transfers due to intense disturbances such as fire, harvest, and slash burning. In such events, live trees die and C transferred to detritus or exported as round wood. With burning, live and detrital C is lost as emissions. Burning can be incomplete, leaving wood, charred and scattered or in unburnt rings and piles. For harvests, all round wood volume is routinely measured, while dispersed and piled residue volumes are typically assessed in field surveys, scaled to a block. Recently, geospatial methods have been used to determine, for an entire block, piled residues using LiDAR or image point clouds (PC) and dispersed residues by analysis of high-resolution imagery. Second-growth Douglas-fir forests on eastern Vancouver Island were examined, 4 blocks at Oyster River (OR) and 2 at Northwest Bay (NB). OR blocks were cut winter 2011, piled spring 2011, field survey, aerial RGB imagery and LiDAR PC acquired fall 2011, piles burned, burn residues surveyed, and post-burn aerial RGB imagery acquired 2012. NB blocks were cut fall 2014, piled spring 2015, field survey, UAV RGB imagery and image PC acquired summer 2015, piles burned and burn residues surveyed spring 2016, and post-burn UAV RGB imagery and PC acquired fall 2016. Volume to biomass conversion used survey species proportions and wood density. At OR, round wood was 261.7 SE 13.1, firewood 1.7 SE 0.3, and dispersed residue by survey, 13.8 SE 3.6 tonnes dry mass (t dm) ha-1. Piled residues were 8.2 SE 0.9 from pile surveys vs. 25.0 SE 5.9 t dm ha-1 from LiDAR PC bulk pile volumes and packing ratios. Post-burn, piles lost 5.8 SE 0.5 from survey of burn residues vs. 18.2 SE 4.7 t dm ha-1 from pile volume changes using 2011 LiDAR PC and 2012 imagery. The percentage of initial merchantable biomass exported as round & fire wood, remaining as dispersed & piled residue, and lost to burning was, respectively, 92.5%, 5.5% and 2% using only field methods vs. 87%, 7% and 6% from

  15. A Wide Spectral Range Reflectance and Luminescence Imaging System

    Directory of Open Access Journals (Sweden)

    Tapani Hirvonen

    2013-10-01

    Full Text Available In this study, we introduce a wide spectral range (200–2500 nm imaging system with a 250 μm minimum spatial resolution, which can be freely modified for a wide range of resolutions and measurement geometries. The system has been tested for reflectance and luminescence measurements, but can also be customized for transmittance measurements. This study includes the performance results of the developed system, as well as examples of spectral images. Discussion of the system relates it to existing systems and methods. The wide range spectral imaging system that has been developed is however highly customizable and has great potential in many practical applications.

  16. SPECTRAL SMILE CORRECTION IN CRISM HYPERSPECTRAL IMAGES

    Science.gov (United States)

    Ceamanos, X.; Doute, S.

    2009-12-01

    The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is affected by a common artifact in "push-broom" sensors, the so-called "spectral smile". As a consequence, both central wavelength and spectral width of the spectral response vary along the across-track dimension, thus giving rise to a shifting and smoothing of spectra (see Fig. 1 (left)). In fact, both effects are greater for spectra on the edges, while they are minimum for data acquired by central detectors, the so-called "sweet spot". The prior artifacts become particularly critical for Martian observations which contain steep spectra such as CO2 ice-rich polar images. Fig. 1 (right) shows the horizontal brightness gradient which appears in every band corresponding to a steep portion of spectra. The correction of CRISM spectral smile is addressed using a two-step method which aims at modifying data sensibly in order to mimic the optimal CRISM response. First, all spectra, which are previously interpolated by cubic splines, are resampled to the "sweet spot" wavelengths in order to overcome the spectra shift. Secondly, the non-uniform spectral width is overcome by mimicking an increase of spectral resolution thanks to a spectral sharpening. In order to minimize noise, only bands particularly suffering from smile are selected. First, bands corresponding to the outliers of the Minimum Noise Transformation (MNF) eigenvector, which corresponds to the MNF band related to smile (MNF-smile), are selected. Then, a spectral neighborhood Θi, which takes into account the local spectral convexity or concavity, is defined for every selected band in order to maximize spectral shape preservation. The proposed sharpening technique takes into account both the instrument parameters and the observed spectra. First, every reflectance value belonging to a Θi is reevaluated by a sharpening which depends on a ratio of the spectral width of the current detector and the "sweet spot" one. Then, the optimal degree of

  17. Source localization of intermittent rhythmic delta activity in a patient with acute confusional migraine: cross-spectral analysis using standardized low-resolution brain electromagnetic tomography (sLORETA).

    Science.gov (United States)

    Kim, Dae-Eun; Shin, Jung-Hyun; Kim, Young-Hoon; Eom, Tae-Hoon; Kim, Sung-Hun; Kim, Jung-Min

    2016-01-01

    Acute confusional migraine (ACM) shows typical electroencephalography (EEG) patterns of diffuse delta slowing and frontal intermittent rhythmic delta activity (FIRDA). The pathophysiology of ACM is still unclear but these patterns suggest neuronal dysfunction in specific brain areas. We performed source localization analysis of IRDA (in the frequency band of 1-3.5 Hz) to better understand the ACM mechanism. Typical IRDA EEG patterns were recorded in a patient with ACM during the acute stage. A second EEG was obtained after recovery from ACM. To identify source localization of IRDA, statistical non-parametric mapping using standardized low-resolution brain electromagnetic tomography was performed for the delta frequency band comparisons between ACM attack and non-attack periods. A difference in the current density maximum was found in the dorsal anterior cingulated cortex (ACC). The significant differences were widely distributed over the frontal, parietal, temporal and limbic lobe, paracentral lobule and insula and were predominant in the left hemisphere. Dorsal ACC dysfunction was demonstrated for the first time in a patient with ACM in this source localization analysis of IRDA. The ACC plays an important role in the frontal attentional control system and acute confusion. This dysfunction of the dorsal ACC might represent an important ACM pathophysiology.

  18. A high resolution solar atlas for fluorescence calculations

    Science.gov (United States)

    Hearn, M. F.; Ohlmacher, J. T.; Schleicher, D. G.

    1983-01-01

    The characteristics required of a solar atlas to be used for studying the fluorescence process in comets are examined. Several sources of low resolution data were combined to provide an absolutely calibrated spectrum from 2250 A to 7000A. Three different sources of high resolution data were also used to cover this same spectral range. The low resolution data were then used to put each high resolution spectrum on an absolute scale. The three high resolution spectra were then combined in their overlap regions to produce a single, absolutely calibrated high resolution spectrum over the entire spectral range.

  19. On Longitudinal Spectral Coherence

    DEFF Research Database (Denmark)

    Kristensen, Leif

    1979-01-01

    It is demonstrated that the longitudinal spectral coherence differs significantly from the transversal spectral coherence in its dependence on displacement and frequency. An expression for the longitudinal coherence is derived and it is shown how the scale of turbulence, the displacement between ...... observation sites and the turbulence intensity influence the results. The limitations of the theory are discussed....

  20. Digital spectral analysis parametric, non-parametric and advanced methods

    CERN Document Server

    Castanié, Francis

    2013-01-01

    Digital Spectral Analysis provides a single source that offers complete coverage of the spectral analysis domain. This self-contained work includes details on advanced topics that are usually presented in scattered sources throughout the literature.The theoretical principles necessary for the understanding of spectral analysis are discussed in the first four chapters: fundamentals, digital signal processing, estimation in spectral analysis, and time-series models.An entire chapter is devoted to the non-parametric methods most widely used in industry.High resolution methods a

  1. H.E.S.S. observations of RX J1713.7-3946 with improved angular and spectral resolution: Evidence for gamma-ray emission extending beyond the X-ray emitting shell

    Science.gov (United States)

    H. E. S. S. Collaboration; Abdalla, H.; Abramowski, A.; Aharonian, F.; Benkhali, F. Ait; Akhperjanian, A. G.; Andersson, T.; Angüner, E. O.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Tjus, J. Becker; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Bulik, T.; Capasso, M.; Carr, J.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chalme-Calvet, R.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Chrétien, M.; Colafrancesco, S.; Cologna, G.; Condon, B.; Conrad, J.; Cui, Y.; Davids, I. D.; Decock, J.; Degrange, B.; Deil, C.; Devin, J.; deWilt, P.; Dirson, L.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O.'C.; Dubus, G.; Dutson, K.; Dyks, J.; Edwards, T.; Egberts, K.; Eger, P.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Fukuyama, T.; Funk, S.; Füßling, M.; Gabici, S.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Gottschall, D.; Goyal, A.; Grondin, M.-H.; Hadasch, D.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holler, M.; Horns, D.; Ivascenko, A.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jogler, T.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kerszberg, D.; Khélifi, B.; Kieffer, M.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krayzel, F.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lefranc, V.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; López-Coto, R.; Lypova, I.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morå, K.; Moulin, E.; Murach, T.; Naurois, M. de; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Öttl, S.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Piel, Q.; Pita, S.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Reimer, A.; Reimer, O.; Renaud, M.; los Reyes, R. de; Rieger, F.; Romoli, C.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Salek, D.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Settimo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Simoni, R.; Sol, H.; Spanier, F.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Takahashi, T.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tuffs, R.; Uchiyama, Y.; van der Walt, D. J.; Eldik, C. van; Rensburg, C. van; Soelen, B. van; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Volpe, F.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zaborov, D.; Zacharias, M.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Żywucka, N.

    2018-04-01

    Supernova remnants exhibit shock fronts (shells) that can accelerate charged particles up to very high energies. In the past decade, measurements of a handful of shell-type supernova remnants in very high-energy gamma rays have provided unique insights into the acceleration process. Among those objects, RX J1713.7-3946 (also known as G347.3-0.5) has the largest surface brightness, allowing us in the past to perform the most comprehensive study of morphology and spatially resolved spectra of any such very high-energy gamma-ray source. Here we present extensive new H.E.S.S. measurements of RX J1713.7-3946, almost doubling the observation time compared to our previous publication. Combined with new improved analysis tools, the previous sensitivity is more than doubled. The H.E.S.S. angular resolution of 0.048° (0.036° above 2 TeV) is unprecedented in gamma-ray astronomy and probes physical scales of 0.8 (0.6) parsec at the remnant's location. The new H.E.S.S. image of RX J1713.7-3946 allows us to reveal clear morphological differences between X-rays and gamma rays. In particular, for the outer edge of the brightest shell region, we find the first ever indication for particles in the process of leaving the acceleration shock region. By studying the broadband energy spectrum, we furthermore extract properties of the parent particle populations, providing new input to the discussion of the leptonic or hadronic nature of the gamma-ray emission mechanism. All images (FITS files) are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/612/A6

  2. Spectral Interferometry with Electron Microscopes

    Science.gov (United States)

    Talebi, Nahid

    2016-01-01

    Interference patterns are not only a defining characteristic of waves, but also have several applications; characterization of coherent processes and holography. Spatial holography with electron waves, has paved the way towards space-resolved characterization of magnetic domains and electrostatic potentials with angstrom spatial resolution. Another impetus in electron microscopy has been introduced by ultrafast electron microscopy which uses pulses of sub-picosecond durations for probing a laser induced excitation of the sample. However, attosecond temporal resolution has not yet been reported, merely due to the statistical distribution of arrival times of electrons at the sample, with respect to the laser time reference. This is however, the very time resolution which will be needed for performing time-frequency analysis. These difficulties are addressed here by proposing a new methodology to improve the synchronization between electron and optical excitations through introducing an efficient electron-driven photon source. We use focused transition radiation of the electron as a pump for the sample. Due to the nature of transition radiation, the process is coherent. This technique allows us to perform spectral interferometry with electron microscopes, with applications in retrieving the phase of electron-induced polarizations and reconstructing dynamics of the induced vector potential. PMID:27649932

  3. Laser's calibration of an AOTF-based spectral colorimeter

    Science.gov (United States)

    Emelianov, Sergey P.; Khrustalev, Vladimir N.; Kochin, Leonid B.; Polosin, Lev L.

    2003-06-01

    The paper is devoted to expedients of AOTF spectral colorimeters calibration. The spectrometer method of color values measuring with reference to spectral colorimeters on AOTF surveyed. The theoretical exposition of spectrometer data processing expedients is offered. The justified source of radiation choice, suitable for calibration of spectral colorimeters is carried out. The experimental results for different acousto-optical mediums and modes of interaction are submitted.

  4. Using Monte Carlo Simulation to Improve the Performance of Semivariograms for Choosing the Remote Sensing Imagery Resolution for Natural Resource Surveys: Case Study on Three Counties in East, Central, and West China

    Directory of Open Access Journals (Sweden)

    Juanle Wang

    2018-01-01

    Full Text Available Semivariograms have been widely used in research to obtain optimal resolutions for ground features. To obtain the semivariogram curve and its attributes (range and sill, parameters including sample size (SS, maximum distance (MD, and group number (GN have to be defined, as well as a mathematic model for fitting the curve. However, a clear guide on parameter setting and model selection is currently not available. In this study, a Monte Carlo simulation-based approach (MCS is proposed to enhance the performance of semivariograms by optimizing the parameters, and case studies in three regions are conducted to determine the optimal resolution for natural resource surveys. Those parameters are optimized one by one through several rounds of MCS. The result shows that exponential model is better than sphere model; sample size has a positive relationship with R2, while the group number has a negative one; increasing the simulation number could improve the accuracy of estimation; and eventually the optimized parameters improved the performance of semivariogram. In case study, the average sizes for three general ground features (grassland, farmland, and forest of three counties (Ansai, Changdu, and Taihe in different geophysical locations of China were acquired and compared, and imagery with an appropriate resolution is recommended. The results show that the ground feature sizes acquired by means of MCS and optimized parameters in this study match well with real land cover patterns.

  5. Hybrid Rayleigh, Raman and TPE fluorescence spectral confocal microscopy of living cells

    NARCIS (Netherlands)

    Pully, V.V.; Lenferink, Aufrid T.M.; Otto, Cornelis

    2010-01-01

    A hybrid fluorescence–Raman confocal microscopy platform is presented, which integrates low-wavenumber-resolution Raman imaging, Rayleigh scatter imaging and two-photon fluorescence (TPE) spectral imaging, fast ‘amplitude-only’ TPE-fluorescence imaging and high-spectral-resolution Raman imaging.

  6. Estimation of spectral kurtosis

    Science.gov (United States)

    Sutawanir

    2017-03-01

    Rolling bearings are the most important elements in rotating machinery. Bearing frequently fall out of service for various reasons: heavy loads, unsuitable lubrications, ineffective sealing. Bearing faults may cause a decrease in performance. Analysis of bearing vibration signals has attracted attention in the field of monitoring and fault diagnosis. Bearing vibration signals give rich information for early detection of bearing failures. Spectral kurtosis, SK, is a parameter in frequency domain indicating how the impulsiveness of a signal varies with frequency. Faults in rolling bearings give rise to a series of short impulse responses as the rolling elements strike faults, SK potentially useful for determining frequency bands dominated by bearing fault signals. SK can provide a measure of the distance of the analyzed bearings from a healthy one. SK provides additional information given by the power spectral density (psd). This paper aims to explore the estimation of spectral kurtosis using short time Fourier transform known as spectrogram. The estimation of SK is similar to the estimation of psd. The estimation falls in model-free estimation and plug-in estimator. Some numerical studies using simulations are discussed to support the methodology. Spectral kurtosis of some stationary signals are analytically obtained and used in simulation study. Kurtosis of time domain has been a popular tool for detecting non-normality. Spectral kurtosis is an extension of kurtosis in frequency domain. The relationship between time domain and frequency domain analysis is establish through power spectrum-autocovariance Fourier transform. Fourier transform is the main tool for estimation in frequency domain. The power spectral density is estimated through periodogram. In this paper, the short time Fourier transform of the spectral kurtosis is reviewed, a bearing fault (inner ring and outer ring) is simulated. The bearing response, power spectrum, and spectral kurtosis are plotted to

  7. Fine-resolution repeat topographic surveying of dryland landscapes using UAS-based structure-from-motion photogrammetry: Assessing accuracy and precision against traditional ground-based erosion measurements

    Science.gov (United States)

    Gillian, Jeffrey K.; Karl, Jason W.; Elaksher, Ahmed; Duniway, Michael C.

    2017-01-01

    Structure-from-motion (SfM) photogrammetry from unmanned aerial system (UAS) imagery is an emerging tool for repeat topographic surveying of dryland erosion. These methods are particularly appealing due to the ability to cover large landscapes compared to field methods and at reduced costs and finer spatial resolution compared to airborne laser scanning. Accuracy and precision of high-resolution digital terrain models (DTMs) derived from UAS imagery have been explored in many studies, typically by comparing image coordinates to surveyed check points or LiDAR datasets. In addition to traditional check points, this study compared 5 cm resolution DTMs derived from fixed-wing UAS imagery with a traditional ground-based method of measuring soil surface change called erosion bridges. We assessed accuracy by comparing the elevation values between DTMs and erosion bridges along thirty topographic transects each 6.1 m long. Comparisons occurred at two points in time (June 2014, February 2015) which enabled us to assess vertical accuracy with 3314 data points and vertical precision (i.e., repeatability) with 1657 data points. We found strong vertical agreement (accuracy) between the methods (RMSE 2.9 and 3.2 cm in June 2014 and February 2015, respectively) and high vertical precision for the DTMs (RMSE 2.8 cm). Our results from comparing SfM-generated DTMs to check points, and strong agreement with erosion bridge measurements suggests repeat UAS imagery and SfM processing could replace erosion bridges for a more synoptic landscape assessment of shifting soil surfaces for some studies. However, while collecting the UAS imagery and generating the SfM DTMs for this study was faster than collecting erosion bridge measurements, technical challenges related to the need for ground control networks and image processing requirements must be addressed before this technique could be applied effectively to large landscapes.

  8. Assessing the role of spectral and intensity cues in spectral ripple detection and discrimination in cochlear-implant users.

    Science.gov (United States)

    Anderson, Elizabeth S; Oxenham, Andrew J; Nelson, Peggy B; Nelson, David A

    2012-12-01

    Measures of spectral ripple resolution have become widely used psychophysical tools for assessing spectral resolution in cochlear-implant (CI) listeners. The objective of this study was to compare spectral ripple discrimination and detection in the same group of CI listeners. Ripple detection thresholds were measured over a range of ripple frequencies and were compared to spectral ripple discrimination thresholds previously obtained from the same CI listeners. The data showed that performance on the two measures was correlated, but that individual subjects' thresholds (at a constant spectral modulation depth) for the two tasks were not equivalent. In addition, spectral ripple detection was often found to be possible at higher rates than expected based on the available spectral cues, making it likely that temporal-envelope cues played a role at higher ripple rates. Finally, spectral ripple detection thresholds were compared to previously obtained speech-perception measures. Results confirmed earlier reports of a robust relationship between detection of widely spaced ripples and measures of speech recognition. In contrast, intensity difference limens for broadband noise did not correlate with spectral ripple detection measures, suggesting a dissociation between the ability to detect small changes in intensity across frequency and across time.

  9. Improvement of high resolution borehole seismics. Part 1: Development of processing methods for VSP surveys. Part 2: Piezoelectric signal transmitter for seismic measurements

    International Nuclear Information System (INIS)

    Cosma, C.; Heikkinen, P.; Pekonen, S.

    1991-05-01

    The purpose of the high resolution borehole seismics project has been to improve the reliability and resolution of seismic methods in the particular environment of nuclear waste repository sites. The results obtained, especially the data processing and interpretation methods developed, are applicable also to other geophysical methods (e.g. Georadar). The goals of the seismic development project have been: the development of processing and interpretation techniques for mapping fractured zones, and the design and construction of a seismic source complying with the requirements of repository site characterization programs. Because these two aspects of the work are very different in nature, we have structured the report as two self contained parts. Part 1 describes the development of interpretive techniques. We have used for demonstrating the effect of different methods a VSP data set collected at the SCV site during Stage 1 of the project. Five techniques have been studied: FK-filtering, three versions of Tau-p filtering and a new technique that we have developed lately, Image Space filtering. Part 2 refers to the construction of the piezoelectric source. Earlier results obtained over short distances with low energy piezoelectric transmitters let us believe that the same principle could be applied for seismic signal transmitters, if solutions for higher energy and lower frequency output were found. The instrument which we have constructed is a cylindrical unit which can be placed in a borehole and is able to produce a radial strain when excited axially. The minimum borehole diameter is 56 mm. (au)

  10. Spectrally accurate contour dynamics

    International Nuclear Information System (INIS)

    Van Buskirk, R.D.; Marcus, P.S.

    1994-01-01

    We present an exponentially accurate boundary integral method for calculation the equilibria and dynamics of piece-wise constant distributions of potential vorticity. The method represents contours of potential vorticity as a spectral sum and solves the Biot-Savart equation for the velocity by spectrally evaluating a desingularized contour integral. We use the technique in both an initial-value code and a newton continuation method. Our methods are tested by comparing the numerical solutions with known analytic results, and it is shown that for the same amount of computational work our spectral methods are more accurate than other contour dynamics methods currently in use

  11. Spectral radius of graphs

    CERN Document Server

    Stevanovic, Dragan

    2015-01-01

    Spectral Radius of Graphs provides a thorough overview of important results on the spectral radius of adjacency matrix of graphs that have appeared in the literature in the preceding ten years, most of them with proofs, and including some previously unpublished results of the author. The primer begins with a brief classical review, in order to provide the reader with a foundation for the subsequent chapters. Topics covered include spectral decomposition, the Perron-Frobenius theorem, the Rayleigh quotient, the Weyl inequalities, and the Interlacing theorem. From this introduction, the

  12. Stellar Spectral Classification with Minimum Within-Class and ...

    Indian Academy of Sciences (India)

    spectral classification methods, and it is widely used in practice. But its ... Digital Sky Survey (SDSS) show that MMSVM performs better than. SVM. Key words. ... to feature extraction, and then the traditional classifier SVM is used to classify the.

  13. Mortality and ST resolution in patients admitted with STEMI: the MOMI survey of emergency service experience in a complex urban area.

    Science.gov (United States)

    Grieco, Niccolò; Sesana, Giovanni; Corrada, Elena; Ieva, Francesca; Paganoni, Annamaria; Marzegalli, Maurizio

    2012-09-01

    Since 2001, the urban area of Milan has been operating a network among 23 cardiac care units, the 118 dispatch centre (national free number for medical emergencies), and the county government health agency called Group for Prehospital Cardiac Emergency. In order to monitor the network activity, time to treatment, and clinical outcome, a periodic survey, called MOMI(2), was repeated two or three times a year. Each survey lasted 30 days and was repeated in comparable periods. Data were stratified for hospital admission mode. We collected data concerning 708 consecutive ST-elevation myocardial infarction (STEMI) patients (male 72.6%; mean age 64.4 years). In these six surveys, we observed a high rate of primary percutaneous coronary intervention (73.2%) and a mortality rate of 6.3%. Using advanced statistical models, we identified age, Killip class, and the symptom onset-to-balloon time as most relevant prognostic factors. Nonparametric test showed that the modality of hospital admittance was the most critical determinant of door-to-balloon time. 12-lead ECG tele-transmission and activation of a fast track directly to the catheterization laboratory are easy action to reduce time to treatment. The experience of the Milan network for cardiac emergency shows how a network coordinating the community, rescue units, and hospitals in a complex urban area and making use of medical technology contributes to the health care of patients with STEMI.

  14. Multi spectral scaling data acquisition system

    International Nuclear Information System (INIS)

    Behere, Anita; Patil, R.D.; Ghodgaonkar, M.D.; Gopalakrishnan, K.R.

    1997-01-01

    In nuclear spectroscopy applications, it is often desired to acquire data at high rate with high resolution. With the availability of low cost computers, it is possible to make a powerful data acquisition system with minimum hardware and software development, by designing a PC plug-in acquisition board. But in using the PC processor for data acquisition, the PC can not be used as a multitasking node. Keeping this in view, PC plug-in acquisition boards with on-board processor find tremendous applications. Transputer based data acquisition board has been designed which can be configured as a high count rate pulse height MCA or as a Multi Spectral Scaler. Multi Spectral Scaling (MSS) is a new technique, in which multiple spectra are acquired in small time frames and are then analyzed. This paper describes the details of this multi spectral scaling data acquisition system. 2 figs

  15. Characterization of the titanium Kβ spectral profile

    International Nuclear Information System (INIS)

    Chantler, C T; Smale, L F; Kinnane, M N; Illig, A J; Kimpton, J A; Crosby, D N

    2013-01-01

    Transition metals have Kα and Kβ characteristic radiation possessing complex asymmetric spectral profiles. Instrumental broadening normally encountered in x-ray experiments shifts features of profiles used for calibration, such as peak energy, by many times the quoted accuracies. We measure and characterize the titanium Kβ spectral profile. The peak energy of the titanium Kβ spectral profile is found to be 4931.966 ± 0.022 eV prior to instrumental broadening. This 4.5 ppm result decreases the uncertainty over the past literature by a factor of 2.6 and is 2.4 standard deviations from the previous standard. The spectrum is analysed and the resolution-free lineshape is extracted and listed for use in other experiments. We also incorporate improvement in analysis applied to earlier results for V Kβ. (paper)

  16. INTERMEDIATE RESOLUTION NEAR-INFRARED SPECTROSCOPY OF 36 LATE M DWARFS

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, R. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Martin, E. L.; Zapatero Osorio, M. R.; Bouy, H. [Centro de Astrobiologia (CSIC-INTA), Ctra. Ajalvir km 4, E-28850 Torrejon de Ardoz, Madrid (Spain); Montgomery, M. M. [Department of Physics, University of Central Florida, P.O. Box 162385, Orlando, FL 32816-2385 (United States); Rodler, F. [Institut de Ciencies de l' Espai (CSIC-IEEC), Campus UAB, Torre C5-parell-2a planta, E-08193 Bellaterra (Spain); Del Burgo, C. [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Aptdo. Postal 51 y 216, 72000 Puebla, Pue. (Mexico); Phan Bao, N. [Department of Physics, HCMIU, Vietnam National University Administrative Building, Block 6, Linh Trung Ward, Thu Duc District, HCM (Viet Nam); Lyubchik, Y.; Pavlenko, Y. [Main Astronomical Observatory of Academy of Sciences of Ukraine, Zabolotnoho, 27, Kyiv 03680 (Ukraine); Tata, R., E-mail: rohit@psu.edu [Instituto de Astrofisica de Canarias, c/Via Lactea, s/n, E-38205 La Laguna, Tenerife, Islas Canarias (Spain)

    2012-10-01

    We present observations of 36 late M dwarfs obtained with the Keck II/NIRSPEC in the J band at a resolution of {approx}20,000. We have measured projected rotational velocities, absolute radial velocities, and pseudo-equivalent widths of atomic lines. Twelve of our targets did not have previous measurements in the literature. For the other 24 targets, we confirm previously reported measurements. We find that 13 stars from our sample have v sin i below our measurement threshold (12 km s{sup -1}) whereas four of our targets are fast rotators (v sin i > 30 km s{sup -1}). As fast rotation causes spectral features to be washed out, stars with low projected rotational velocities are sought for radial velocity surveys. At our intermediate spectral resolution, we have confirmed the identification of neutral atomic lines reported in McLean et al. We also calculated pseudo-equivalent widths of 12 atomic lines. Our results confirm that the pseudo-equivalent width of K I lines is strongly dependent on spectral types. We observe that the pseudo-equivalent width of Fe I and Mn I lines remains fairly constant with later spectral type. We suggest that these lines are particularly suitable for deriving metallicities for late M dwarfs.

  17. Effect of input spectrum on the spectral switch characteristics in a white-light Michelson interferometer.

    Science.gov (United States)

    Brundavanam, Maruthi M; Viswanathan, Nirmal K; Rao, D Narayana

    2009-12-01

    We report here a detailed experimental study to demonstrate the effect of source spectral characteristics such as spectral bandwidth (Deltalambda), peak wavelength (lambda(0)), and shape of the spectrum on the spectral shifts and spectral switches measured due to temporal correlation in a white-light Michelson interferometer operated in the spectral domain. Behavior of the spectral switch characteristics such as the switch position, switch amplitude, and switch symmetry are discussed in detail as a function of optical path difference between the interfering beams. The experimental results are compared with numerical calculations carried out using interference law in the spectral domain with modified source spectral characteristics. On the basis of our results we feel that our study is of critical importance in the selection of source spectral characteristics to further improve the longitudinal resolution or the measurement sensitivity in spectral-domain optical coherence tomography and microscopy.

  18. Resolution propositions

    International Nuclear Information System (INIS)

    2003-05-01

    To put a resolution to the meeting in relation with the use of weapons made of depleted uranium is the purpose of this text. The situation of the use of depleted uranium by France during the Gulf war and other recent conflicts will be established. This resolution will give the most strict recommendations face to the eventual sanitary and environmental risks in the use of these kind of weapons. (N.C.)

  19. Spectral unmixing: estimating partial abundances

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2009-01-01

    Full Text Available techniques is complicated when considering very similar spectral signatures. Iron-bearing oxide/hydroxide/sulfate minerals have similar spectral signatures. The study focuses on how could estimates of abundances of spectrally similar iron-bearing oxide...

  20. Rectangular spectral collocation

    KAUST Repository

    Driscoll, Tobin A.; Hale, Nicholas

    2015-01-01

    Boundary conditions in spectral collocation methods are typically imposed by removing some rows of the discretized differential operator and replacing them with others that enforce the required conditions at the boundary. A new approach based upon

  1. Vowel Inherent Spectral Change

    CERN Document Server

    Assmann, Peter

    2013-01-01

    It has been traditional in phonetic research to characterize monophthongs using a set of static formant frequencies, i.e., formant frequencies taken from a single time-point in the vowel or averaged over the time-course of the vowel. However, over the last twenty years a growing body of research has demonstrated that, at least for a number of dialects of North American English, vowels which are traditionally described as monophthongs often have substantial spectral change. Vowel Inherent Spectral Change has been observed in speakers’ productions, and has also been found to have a substantial effect on listeners’ perception. In terms of acoustics, the traditional categorical distinction between monophthongs and diphthongs can be replaced by a gradient description of dynamic spectral patterns. This book includes chapters addressing various aspects of vowel inherent spectral change (VISC), including theoretical and experimental studies of the perceptually relevant aspects of VISC, the relationship between ar...

  2. Spectral characterization of superficial coal groups

    International Nuclear Information System (INIS)

    Ahmad, I.; Khan, M.A.; Ishaq, M.; Shakirullah; Bahadur, A.

    2004-01-01

    Spectral characterization of superficial coal groups was performed in KBr pellets. KBr Pellets were prepared for virgin and variously pretreated coal samples. Spectra of satisfactory resolution were obtained in wave number range-4000-400 cm /sup -1/. Presence of broad absorption bands corresponds to hydroxyl, carbonyl, carboxyl and phenolic functionalities in the spectra clearly define their presence in all samples understudy. Forced oxidation proved effective for oxidation of both aliphatic and aromatic configurations, which can be revealed from the respective spectra. (author)

  3. Spectrally selective glazings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-08-01

    Spectrally selective glazing is window glass that permits some portions of the solar spectrum to enter a building while blocking others. This high-performance glazing admits as much daylight as possible while preventing transmission of as much solar heat as possible. By controlling solar heat gains in summer, preventing loss of interior heat in winter, and allowing occupants to reduce electric lighting use by making maximum use of daylight, spectrally selective glazing significantly reduces building energy consumption and peak demand. Because new spectrally selective glazings can have a virtually clear appearance, they admit more daylight and permit much brighter, more open views to the outside while still providing the solar control of the dark, reflective energy-efficient glass of the past. This Federal Technology Alert provides detailed information and procedures for Federal energy managers to consider spectrally selective glazings. The principle of spectrally selective glazings is explained. Benefits related to energy efficiency and other architectural criteria are delineated. Guidelines are provided for appropriate application of spectrally selective glazing, and step-by-step instructions are given for estimating energy savings. Case studies are also presented to illustrate actual costs and energy savings. Current manufacturers, technology users, and references for further reading are included for users who have questions not fully addressed here.

  4. SPECTRAL FILTRATION OF IMAGES BY MEANS OF DISPERSIVE SYSTEMS

    Directory of Open Access Journals (Sweden)

    I. M. Gulis

    2016-01-01

    Full Text Available Instruments for spectral filtration of images are an important element of the systems used in remote sensing, medical diagnostics, in-process measurements. The aim of this study is analysis of the functional features and characteristics of the proposed two image monochromator versions which are based on dispersive spectral filtering. The first is based on the use of a dispersive monochromator, where collimating and camera lenses form a telescopic system, the dispersive element of which is within the intermediate image plane. The second version is based on an imaging double monochromator with dispersion subtraction by back propagation. For the telescopic system version, the spectral and spatial resolutions are estimated, the latter being limited by aberrations and diffraction from the entrance slit. The device has been numerically simulated and prototyped. It is shown that for the spectral bandwidth 10 nm (visible spectral range, the aberration-limited spot size is from 10–20 μm at the image center to about 30 μm at the image periphery for the image size 23–27 mm. The monochromator with dispersion subtraction enables one to vary the spectral resolution (up to 1 nm and higher by changing the intermediate slit width. But the distinctive feature is a significant change in the selected central wavelength over the image field. The considered designs of dispersive image monochromators look very promising due to the particular advantages over the systems based on tunable filters as regards the spectral resolution, fast tuning, and the spectral contrast. The monochromator based on a telescopic system has a simple design and a rather large image field but it also has a limited light throughput due to small aperture size. The monochromator with dispersion subtraction has higher light throughput, can provide high spectral resolution when recording a full data cube in a series of measuring acts for different dispersive element positions. 

  5. Spectral Classification of Asteroids by Random Forest

    Science.gov (United States)

    Huang, C.; Ma, Y. H.; Zhao, H. B.; Lu, X. P.

    2016-09-01

    With the increasing asteroid spectral and photometric data, a variety of classification methods for asteroids have been proposed. This paper classifies asteroids based on the observations of Sloan Digital Sky Survey (SDSS) Moving Object Catalogue (MOC) by using the random forest algorithm. With the training data derived from the taxonomies of Tholen, Bus, Lazzaro, DeMeo, and Principal Component Analysis, we classify 48642 asteroids according to g, r, i, and z SDSS magnitudes. In this way, asteroids are divided into 8 spectral classes (C, X, S, B, D, K, L, and V).

  6. Low resolution infrared spectra of quasars

    International Nuclear Information System (INIS)

    Soifer, B.T.; Neugebauer, G.; Oke, J.B.; Matthews, K.

    1980-01-01

    Low resolution spectra of a significant sample of quasars show that the Paschen α and Balmer line ratios do not agree with the radiative recombination case B result and vary widely within the quasars sampled. The range in Pα:Hβ ratios is a factor of approximately 6, while the range in Lyα:Hα ratios is a factor of approximately 5. For the Pα:Balmer series, the deviations from case B recombination are not consistent with reddening, but appear, within large dispersions, to be consistent with optical depth effects in the Balmer lines affecting the line ratios. The Lyα:Hα ratio is, however, correlated with the continuum spectral index, and can be explained as due to reddening affecting both the lines and continuum. Recent observational results based on a joint infrared/optical survey of the hydrogen line spectra of a significant number of the brightest low and high redshift quasars are summarised. This survey includes 12 quasars in the redshift range 0.07 1.5, where Hα and/or Hβ is redshifted into the 1.65μm or 2.2μm atmospheric windows. (Auth.)

  7. Spectral line polarimetry with a channeled polarimeter.

    Science.gov (United States)

    van Harten, Gerard; Snik, Frans; Rietjens, Jeroen H H; Martijn Smit, J; Keller, Christoph U

    2014-07-01

    Channeled spectropolarimetry or spectral polarization modulation is an accurate technique for measuring the continuum polarization in one shot with no moving parts. We show how a dual-beam implementation also enables spectral line polarimetry at the intrinsic resolution, as in a classic beam-splitting polarimeter. Recording redundant polarization information in the two spectrally modulated beams of a polarizing beam-splitter even provides the possibility to perform a postfacto differential transmission correction that improves the accuracy of the spectral line polarimetry. We perform an error analysis to compare the accuracy of spectral line polarimetry to continuum polarimetry, degraded by a residual dark signal and differential transmission, as well as to quantify the impact of the transmission correction. We demonstrate the new techniques with a blue sky polarization measurement around the oxygen A absorption band using the groundSPEX instrument, yielding a polarization in the deepest part of the band of 0.160±0.010, significantly different from the polarization in the continuum of 0.2284±0.0004. The presented methods are applicable to any dual-beam channeled polarimeter, including implementations for snapshot imaging polarimetry.

  8. Near-infrared metallicities, radial velocities, and spectral types for 447 nearby M dwarfs

    Energy Technology Data Exchange (ETDEWEB)

    Newton, Elisabeth R.; Charbonneau, David; Irwin, Jonathan; Berta-Thompson, Zachory K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Rojas-Ayala, Barbara [Centro de Astrofsica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Covey, Kevin [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Lloyd, James P., E-mail: enewton@cfa.harvard.edu [Department of Astronomy, Cornell University, 226 Space Sciences Building, Ithaca, NY 14853 (United States)

    2014-01-01

    We present metallicities, radial velocities, and near-infrared (NIR) spectral types for 447 M dwarfs determined from moderate resolution (R ≈ 2000) NIR spectra obtained with the NASA Infrared Telescope Facility (IRTF)/SpeX. These M dwarfs are primarily targets of the MEarth Survey, a transiting planet survey searching for super Earths around mid-to-late M dwarfs within 33 pc. We present NIR spectral types for each star and new spectral templates for the IRTF in the Y, J, H, and K-bands, created using M dwarfs with near-solar metallicities. We developed two spectroscopic distance calibrations that use NIR spectral type or an index based on the curvature of the K-band continuum. Our distance calibration has a scatter of 14%. We searched 27 NIR spectral lines and 10 spectral indices for metallicity sensitive features, taking into account correlated noise in our estimates of the errors on these parameters. We calibrated our relation using 36 M dwarfs in common proper pairs with an F-, G-, or K-type star of known metallicity. We validated the physical association of these pairs using proper motions, radial velocities, and spectroscopic distance estimates. Our resulting metallicity calibration uses the sodium doublet at 2.2 μm as the sole indicator for metallicity. It has an accuracy of 0.12 dex inferred from the scatter between the metallicities of the primaries and the estimated metallicities of the secondaries. Our relation is valid for NIR spectral types from M1V to M5V and for –1.0 dex < [Fe/H] < +0.35 dex. We present a new color-color metallicity relation using J – H and J – K colors that directly relates two observables: the distance from the M dwarf main sequence and equivalent width of the sodium line at 2.2 μm. We used radial velocities of M dwarf binaries, observations at different epochs, and comparison between our measurements and precisely measured radial velocities to demonstrate a 4 km s{sup –1} accuracy.

  9. Insight into Resolution Enhancement in Generalized Two-Dimensional Correlation Spectroscopy

    OpenAIRE

    Ma, Lu; Sikirzhytski, Vitali; Hong, Zhenmin; Lednev, Igor K.; Asher, Sanford A.

    2013-01-01

    Generalized two-dimensional correlation spectroscopy (2D COS) can be used to enhance spectral resolution in order to help differentiate highly overlapped spectral bands. Despite the numerous extensive 2D COS investigations, the origin of the 2D spectral resolution enhancement mechanism(s) are not completely understood. In the work here we studied the 2D COS of simulated spectra in order to develop new insights into the dependence of the 2D COS spectral features on the overlapping band separat...

  10. Assessing the Accuracy of High Resolution Digital Surface Models Computed by PhotoScan® and MicMac® in Sub-Optimal Survey Conditions

    Directory of Open Access Journals (Sweden)

    Marion Jaud

    2016-06-01

    Full Text Available For monitoring purposes and in the context of geomorphological research, Unmanned Aerial Vehicles (UAV appear to be a promising solution to provide multi-temporal Digital Surface Models (DSMs and orthophotographs. There are a variety of photogrammetric software tools available for UAV-based data. The objective of this study is to investigate the level of accuracy that can be achieved using two of these software tools: Agisoft PhotoScan® Pro and an open-source alternative, IGN© MicMac®, in sub-optimal survey conditions (rugged terrain, with a large variety of morphological features covering a range of roughness sizes, poor GPS reception. A set of UAV images has been taken by a hexacopter drone above the Rivière des Remparts, a river on Reunion Island. This site was chosen for its challenging survey conditions: the topography of the study area (i involved constraints on the flight plan; (ii implied errors on some GPS measurements; (iii prevented an optimal distribution of the Ground Control Points (GCPs and; (iv was very complex to reconstruct. Several image processing tests are performed with different scenarios in order to analyze the sensitivity of each software package to different parameters (image quality, numbers of GCPs, etc.. When computing the horizontal and vertical errors within a control region on a set of ground reference targets, both methods provide rather similar results. A precision up to 3–4 cm is achievable with these software packages. The DSM quality is also assessed over the entire study area comparing PhotoScan DSM and MicMac DSM with a Terrestrial Laser Scanner (TLS point cloud. PhotoScan and MicMac DSM are also compared at the scale of particular features. Both software packages provide satisfying results: PhotoScan is more straightforward to use but its source code is not open; MicMac is recommended for experimented users as it is more flexible.

  11. Spectral Ripple Discrimination in Normal Hearing Infants

    Science.gov (United States)

    Horn, David L.; Won, Jong Ho; Rubinstein, Jay T.; Werner, Lynne A.

    2016-01-01

    Objectives Spectral resolution is a correlate of open-set speech understanding in post-lingually deaf adults as well as pre-lingually deaf children who use cochlear implants (CIs). In order to apply measures of spectral resolution to assess device efficacy in younger CI users, it is necessary to understand how spectral resolution develops in NH children. In this study, spectral ripple discrimination (SRD) was used to measure listeners’ sensitivity to a shift in phase of the spectral envelope of a broadband noise. Both resolution of peak to peak location (frequency resolution) and peak to trough intensity (across-channel intensity resolution) are required for SRD. Design SRD was measured as the highest ripple density (in ripples per octave) for which a listener could discriminate a 90 degree shift in phase of the sinusoidally-modulated amplitude spectrum. A 2X3 between subjects design was used to assess the effects of age (7-month-old infants versus adults) and ripple peak/trough “depth” (10, 13, and 20 dB) on SRD in normal hearing listeners (Experiment 1). In Experiment 2, SRD thresholds in the same age groups were compared using a task in which ripple starting phases were randomized across trials to obscure within-channel intensity cues. In Experiment 3, the randomized starting phase method was used to measure SRD as a function of age (3-month-old infants, 7-month-old infants, and young adults) and ripple depth (10 and 20 dB in repeated measures design). Results In Experiment 1, there was a significant interaction between age and ripple depth. The Infant SRDs were significantly poorer than the adult SRDs at 10 and 13 dB ripple depths but adult-like at 20 dB depth. This result is consistent with immature across-channel intensity resolution. In contrast, the trajectory of SRD as a function of depth was steeper for infants than adults suggesting that frequency resolution was better in infants than adults. However, in Experiment 2 infant performance was

  12. SPAM- SPECTRAL ANALYSIS MANAGER (UNIX VERSION)

    Science.gov (United States)

    Solomon, J. E.

    1994-01-01

    The Spectral Analysis Manager (SPAM) was developed to allow easy qualitative analysis of multi-dimensional imaging spectrometer data. Imaging spectrometers provide sufficient spectral sampling to define unique spectral signatures on a per pixel basis. Thus direct material identification becomes possible for geologic studies. SPAM provides a variety of capabilities for carrying out interactive analysis of the massive and complex datasets associated with multispectral remote sensing observations. In addition to normal image processing functions, SPAM provides multiple levels of on-line help, a flexible command interpretation, graceful error recovery, and a program structure which can be implemented in a variety of environments. SPAM was designed to be visually oriented and user friendly with the liberal employment of graphics for rapid and efficient exploratory analysis of imaging spectrometry data. SPAM provides functions to enable arithmetic manipulations of the data, such as normalization, linear mixing, band ratio discrimination, and low-pass filtering. SPAM can be used to examine the spectra of an individual pixel or the average spectra over a number of pixels. SPAM also supports image segmentation, fast spectral signature matching, spectral library usage, mixture analysis, and feature extraction. High speed spectral signature matching is performed by using a binary spectral encoding algorithm to separate and identify mineral components present in the scene. The same binary encoding allows automatic spectral clustering. Spectral data may be entered from a digitizing tablet, stored in a user library, compared to the master library containing mineral standards, and then displayed as a timesequence spectral movie. The output plots, histograms, and stretched histograms produced by SPAM can be sent to a lineprinter, stored as separate RGB disk files, or sent to a Quick Color Recorder. SPAM is written in C for interactive execution and is available for two different

  13. On deriving transport pathways and morphodynamics in a tidal inlet from high-resolution MBES and LiDAR surveys: the Knudedyb tidal inlet in the Danish Wadden Sea

    DEFF Research Database (Denmark)

    Ernstsen, Verner Brandbyge; Lefebvre, Alice; Fraccascia, Serena

    and topobathymetric surveys using high-resolution red and green Light Detection And Ranging (LiDAR), respectively. Detailed digital elevation models with a grid cell size of 1 m x 1 m were generated and analysed geomorphometrically. The analyses reveal a main ebb-directed net sand transport in the main channel......; however, due to the geometry of the main channel, displaying a confluent meander bend, confined areas in the main channel are characterised by an opposite-directed net sand transport. In the inter-tidal areas the main net sand transport is flood-directed. However, also here the analyses reveal...... that during storm events with winds from SW, sand is transported from the inlet channel to the intertidal flat. Hence, in addition to the typical main sand transport directions with net export in the inlet channel and net import over the adjacent inter-tidal flats, these investigations suggest an exchange...

  14. Spectral analysis and filter theory in applied geophysics

    CERN Document Server

    Buttkus, Burkhard

    2000-01-01

    This book is intended to be an introduction to the fundamentals and methods of spectral analysis and filter theory and their appli­ cations in geophysics. The principles and theoretical basis of the various methods are described, their efficiency and effectiveness eval­ uated, and instructions provided for their practical application. Be­ sides the conventional methods, newer methods arediscussed, such as the spectral analysis ofrandom processes by fitting models to the ob­ served data, maximum-entropy spectral analysis and maximum-like­ lihood spectral analysis, the Wiener and Kalman filtering methods, homomorphic deconvolution, and adaptive methods for nonstation­ ary processes. Multidimensional spectral analysis and filtering, as well as multichannel filters, are given extensive treatment. The book provides a survey of the state-of-the-art of spectral analysis and fil­ ter theory. The importance and possibilities ofspectral analysis and filter theory in geophysics for data acquisition, processing an...

  15. CRISS power spectral density

    International Nuclear Information System (INIS)

    Vaeth, W.

    1979-04-01

    The correlation of signal components at different frequencies like higher harmonics cannot be detected by a normal power spectral density measurement, since this technique correlates only components at the same frequency. This paper describes a special method for measuring the correlation of two signal components at different frequencies: the CRISS power spectral density. From this new function in frequency analysis, the correlation of two components can be determined quantitatively either they stem from one signal or from two diverse signals. The principle of the method, suitable for the higher harmonics of a signal as well as for any other frequency combinations is shown for the digital frequency analysis technique. Two examples of CRISS power spectral densities demonstrates the operation of the new method. (orig.) [de

  16. Parametric Explosion Spectral Model

    Energy Technology Data Exchange (ETDEWEB)

    Ford, S R; Walter, W R

    2012-01-19

    Small underground nuclear explosions need to be confidently detected, identified, and characterized in regions of the world where they have never before occurred. We develop a parametric model of the nuclear explosion seismic source spectrum derived from regional phases that is compatible with earthquake-based geometrical spreading and attenuation. Earthquake spectra are fit with a generalized version of the Brune spectrum, which is a three-parameter model that describes the long-period level, corner-frequency, and spectral slope at high-frequencies. Explosion spectra can be fit with similar spectral models whose parameters are then correlated with near-source geology and containment conditions. We observe a correlation of high gas-porosity (low-strength) with increased spectral slope. The relationship between the parametric equations and the geologic and containment conditions will assist in our physical understanding of the nuclear explosion source.

  17. Photovoltaic spectral responsivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Emery, K.; Dunlavy, D.; Field, H.; Moriarty, T. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    This paper discusses the various elemental random and nonrandom error sources in typical spectral responsivity measurement systems. The authors focus specifically on the filter and grating monochrometer-based spectral responsivity measurement systems used by the Photovoltaic (PV) performance characterization team at NREL. A variety of subtle measurement errors can occur that arise from a finite photo-current response time, bandwidth of the monochromatic light, waveform of the monochromatic light, and spatial uniformity of the monochromatic and bias lights; the errors depend on the light source, PV technology, and measurement system. The quantum efficiency can be a function of he voltage bias, light bias level, and, for some structures, the spectral content of the bias light or location on the PV device. This paper compares the advantages and problems associated with semiconductor-detector-based calibrations and pyroelectric-detector-based calibrations. Different current-to-voltage conversion and ac photo-current detection strategies employed at NREL are compared and contrasted.

  18. Testing the spectral resolutions of the new multispectral sensors for ...

    African Journals Online (AJOL)

    S.R.GCAYI

    1School of Agriculture, Earth and Environmental Sciences, Pietermaritzburg .... sunny and cloud-free conditions between 10h00 am and 14h00 pm local ..... and crop models: the case of nitrogen management', Journal of Experimental Botany, vol. .... using a satellite-based Climate-Variability Impact Index' Agricultural and ...

  19. Passive Standoff Super Resolution Imaging using Spatial-Spectral Multiplexing

    Science.gov (United States)

    2017-08-14

    OPD is mainly influenced by the indices of refraction and thicknesses for the two glass plates/fluids (n1/t1 and n2/t2) and the angle of incidence...the algorithm’s robustness. To be specific, this reconstruction algorithm is shown to be effective on both smoothly varying and point cloud objects...applications in the field of hydrology, oceanography, glaciology, forest, climate , urban, military and meteorology [62]. With remotely sensed images

  20. Spectrally enhanced image resolution of tooth enamel surfaces

    Science.gov (United States)

    Zhang, Liang; Nelson, Leonard Y.; Berg, Joel H.; Seibel, Eric J.

    2012-01-01

    Short-wavelength 405 nm laser illumination of surface dental enamel using an ultrathin scanning fiber endoscope (SFE) produced enhanced detail of dental topography. The surfaces of human extracted teeth and artificial erosions were imaged with 405 nm, 444 nm, 532 nm, or 635 nm illumination lasers. The obtained images were then processed offline to compensate for any differences in the illumination beam diameters between the different lasers. Scattering and absorption coefficients for a Monte Carlo model of light propagation in dental enamel for 405 nm were scaled from published data at 532 nm and 633 nm. The value of the scattering coefficient used in the model was scaled from the coefficients at 532 nm and 633 nm by the inverse third power of wavelength. Simulations showed that the penetration depth of short-wavelength illumination is localized close to the enamel surface, while long-wavelength illumination travels much further and is backscattered from greater depths. Therefore, images obtained using short wavelength laser are not contaminated by the superposition of light reflected from enamel tissue at greater depths. Hence, the SFE with short-wavelength illumination may make it possible to visualize surface manifestations of phenomena such as demineralization, thus better aiding the clinician in the detection of early caries.

  1. The Trade-Off Between Privacy and Geographic Data Resolution. a Case of GPS Trajectories Combined with the Social Survey Results

    Science.gov (United States)

    Sila-Nowicka, K.; Thakuriah, P.

    2016-06-01

    Trajectory datasets are being generated in great volumes due to high levels of Global Positioning System (GPS) and Location-Based Services (LBS) use. Such data are increasingly being collected for a variety of academic, industrial and recreational reasons, sometimes together with other strands of personal data such as socio-demographic, social survey and other sensor data carried/worn by the person. In such cases, not only are movement data of a person available but also data on potentially a wide variety of other personal and household attributes. Making such person-level data available for analytics opens up the possibility of new directions in analysing, studying and understanding human behaviour, which is typically not possible with GPS trajectory datasets alone. At the same time, the GPS data should be released in a privacy-preserving way that takes into account the possibility of re-identification of individuals from quasi-identifiers available from other data strands. De-identification in these strands may be risked due to uniquely identifiable information on significant locations and other spatial behaviours and choices detected from GPS trajectories. Using a multimodal dataset that includes a GPS archive from 358 individuals, and by considering a number of alternative privacy-enhancing approaches, we look at the potential for privacy preservation when personally-identifiable data are available from multiple data strands, for the specific purpose of data to be released for transport research.

  2. THE TRADE-OFF BETWEEN PRIVACY AND GEOGRAPHIC DATA RESOLUTION. A CASE OF GPS TRAJECTORIES COMBINED WITH THE SOCIAL SURVEY RESULTS

    Directory of Open Access Journals (Sweden)

    K. Sila-Nowicka

    2016-06-01

    Full Text Available Trajectory datasets are being generated in great volumes due to high levels of Global Positioning System (GPS and Location-Based Services (LBS use. Such data are increasingly being collected for a variety of academic, industrial and recreational reasons, sometimes together with other strands of personal data such as socio-demographic, social survey and other sensor data carried/worn by the person. In such cases, not only are movement data of a person available but also data on potentially a wide variety of other personal and household attributes. Making such person-level data available for analytics opens up the possibility of new directions in analysing, studying and understanding human behaviour, which is typically not possible with GPS trajectory datasets alone. At the same time, the GPS data should be released in a privacy-preserving way that takes into account the possibility of re-identification of individuals from quasi-identifiers available from other data strands. De-identification in these strands may be risked due to uniquely identifiable information on significant locations and other spatial behaviours and choices detected from GPS trajectories. Using a multimodal dataset that includes a GPS archive from 358 individuals, and by considering a number of alternative privacy-enhancing approaches, we look at the potential for privacy preservation when personally-identifiable data are available from multiple data strands, for the specific purpose of data to be released for transport research.

  3. High resolution aeromagnetic and radiometric survey in the Hokusatsu district, Japan; Hokusatsu Kushikino chiiki ni okeru kobunkaino kuchu jiki hoshano tansa kekka ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Hishida, H; Yoshioka, K [Metal Mining Agency of Japan, Tokyo (Japan)

    1997-10-22

    In FY 1996, aeromagnetic and radiometric survey was performed in the whole area of Hokusatsu district using a helicopter fixed with a stinger mount system with high density 200 m line spacing at low altitude of 80 m, which was the first in Japan. Based on the existing geological maps, Landsat TM data and radiometric data, lithologies and geological structures were extracted in response to individual magnetic characteristics in the whole magnetic map. Obtained geological characteristics are as follows. Straight magnetic anomalies suggested volcanic lava flows. Isolated ring-shaped magnetic anomalies suggested intrusive rocks. Ring-shaped weak magnetic anomalies suggested the centers of volcanoes. Wide range intense magnetic anomalies were caused by deep intrusive rocks. Wide range weak magnetic anomalies were caused by dissipation of magnetite due to hydrothermal alteration. Faults and fracture zones were recognized as linear configurations of magnetic anomaly and divided magnetic anomalies. Based on these results, local geological structures, hydrothermal alterations, and mineralization of known ore deposits were interpreted. 6 refs., 5 figs.

  4. Time-resolved spectral measurements above 80 A

    International Nuclear Information System (INIS)

    Kauffman, R.L.; Ceglio, N.; Medecki, H.

    1983-01-01

    We have made time-resolved spectral measurements above 80 A from laser-produced plasmas. These are made using a transmission grating spectrograph whose primary components are a cylindrically-curved x-ray mirror for light collection, a transmission grating for spectral dispersions, and an x-ray streak camera for temporal resolution. A description of the instrument and an example of the data are given

  5. ARM Climate Research Facility Spectral Surface Albedo Value-Added Product (VAP) Report

    Energy Technology Data Exchange (ETDEWEB)

    McFarlane, S; Gaustad, K; Long, C; Mlawer, E

    2011-07-15

    This document describes the input requirements, output data products, and methodology for the Spectral Surface Albedo (SURFSPECALB) value-added product (VAP). The SURFSPECALB VAP produces a best-estimate near-continuous high spectral resolution albedo data product using measurements from multifilter radiometers (MFRs). The VAP first identifies best estimates for the MFR downwelling and upwelling shortwave irradiance values, and then calculates narrowband spectral albedo from these best-estimate irradiance values. The methodology for finding the best-estimate values is based on a simple process of screening suspect data and backfilling screened and missing data with estimated values when possible. The resulting best-estimate MFR narrowband spectral albedos are used to determine a daily surface type (snow, 100% vegetation, partial vegetation, or 0% vegetation). For non-snow surfaces, a piecewise continuous function is used to estimate a high spectral resolution albedo at 1 min temporal and 10 cm-1 spectral resolution.

  6. Spectral analysis by correlation

    International Nuclear Information System (INIS)

    Fauque, J.M.; Berthier, D.; Max, J.; Bonnet, G.

    1969-01-01

    The spectral density of a signal, which represents its power distribution along the frequency axis, is a function which is of great importance, finding many uses in all fields concerned with the processing of the signal (process identification, vibrational analysis, etc...). Amongst all the possible methods for calculating this function, the correlation method (correlation function calculation + Fourier transformation) is the most promising, mainly because of its simplicity and of the results it yields. The study carried out here will lead to the construction of an apparatus which, coupled with a correlator, will constitute a set of equipment for spectral analysis in real time covering the frequency range 0 to 5 MHz. (author) [fr

  7. Spectral backward radiation profile

    International Nuclear Information System (INIS)

    Kwon, Sung Duck; Lee, Keun Hyun; Kim, Bo Ra; Yoon, Suk Soo

    2004-01-01

    Ultrasonic backward radiation profile is frequency-dependent when incident region has deptional gradient of acoustical properties or multi-layers. Until now, we have measured the profiles of principal frequencies of used transducers so that it was not easy to understand the change of the frequency component and spectrum of backward radiation from the profile. We tried to measure the spectral backward radiation profiles using DFP(digital filer package) Lecroy DSO. The very big changes in the shape and pattern of spectral backward radiation profiles leads to the conclusion that this new try could be very effective tool to evaluate frequency dependent surface area.

  8. Spectroscopic Characterisation of CARMENES Target Candidates from FEROS, CAFE and HRS High-Resolution Spectra

    Science.gov (United States)

    Passegger, Vera Maria; Reiners, Ansgar; Jeffers, Sandra V.; Wende, Sebastian; Schöfer, Patrick; Amado, Pedro J.; Caballero, Jose A.; Montes, David; Mundt, Reinhard; Ribas, Ignasi; Quirrenbach, Andreas

    2016-07-01

    CARMENES (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) started a new planet survey on M-dwarfs in January this year. The new high-resolution spectrographs are operating in the visible and near-infrared at Calar Alto Observatory. They will perform high-accuracy radial-velocity measurements (goal 1 m s-1) of about 300 M-dwarfs with the aim to detect low-mass planets within habitable zones. We characterised the candidate sample for CARMENES and provide fundamental parameters for these stars in order to constrain planetary properties and understand star-planet systems. Using state-of-the-art model atmospheres (PHOENIX-ACES) and χ2-minimization with a downhill-simplex method we determine effective temperature, surface gravity and metallicity [Fe/H] for high-resolution spectra of around 480 stars of spectral types M0.0-6.5V taken with FEROS, CAFE and HRS. We find good agreement between the models and our observed high-resolution spectra. We show the performance of the algorithm, as well as results, parameter and spectral type distributions for the CARMENES candidate sample, which is used to define the CARMENES target sample. We also present first preliminary results obtained from CARMENES spectra.

  9. Multi-spectral optical scanners for commercial earth observation missions

    Science.gov (United States)

    Schröter, Karin; Engel, Wolfgang; Berndt, Klaus

    2017-11-01

    In recent years, a number of commercial Earth observation missions have been initiated with the aim to gather data in the visible and near-infrared wavelength range. Some of these missions aim at medium resolution (5 to 10 m) multi-spectral imaging with the special background of daily revisiting. Typical applications aim at monitoring of farming area for growth control and harvest prediction, irrigation control, or disaster monitoring such as hail damage in farming, or flood survey. In order to arrive at profitable business plans for such missions, it is mandatory to establish the space segment, i.e. the spacecraft with their opto -electronic payloads, at minimum cost while guaranteeing maximum reliability for mission success. As multiple spacecraft are required for daily revisiting, the solutions are typically based on micro-satellites. This paper presents designs for multi-spectral opto-electric scanners for this type of missions. These designs are drive n by minimum mass and power budgets of microsatellites, and the need for minimum cost. As a consequence, it is mandatory to arrive at thermally robust, compact telescope designs. The paper gives a comparison between refractive, catadioptric, and TMA optics. For mirror designs, aluminium and Zerodur mirror technologies are briefly discussed. State-of-the art focal plane designs are presented. The paper also addresses the choice of detector technologies such as CCDs and CMOS Active Pixel Sensors. The electronics of the multi-spectral scanners represent the main design driver regarding power consumption, reliability, and (most often) cost. It can be subdivided into the detector drive electronics, analog and digital data processing chains, the data mass memory unit, formatting and down - linking units, payload control electronics, and local power supply. The paper gives overviews and trade-offs between data compression strategies and electronics solutions, mass memory unit designs, and data formatting approaches

  10. Glacitectonic rafting and associated deformation of mid-Pleistocene glacigenic sediments, near Central Graben, central North Sea; results of a 2D High-