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Sample records for angular resolution observations

  1. High angular resolution SZ observations with NIKA and NIKA2

    CERN Document Server

    Comis, B; Ade, P; André, P; Arnaud, M; Bartalucci, I; Beelen, A; Benoît, A; Bideaud, A; Billot, N; Bourrion, O; Calvo, M; Catalano, A; Coiffard, G; Désert, F -X; Doyle, S; Goupy, J; Kramer, C; Lagache, G; Leclercq, S; Macías-Pérez, J F; Mauskopf, P; Mayet, F; Monfardini, A; Pajot, F; Pascale, E; Perotto, L; Pointecouteau, E; Pisano, G; Ponthieu, N; Pratt, G W; Revéret, V; Ritacco, A; Rodriguez, L; Romero, C; Ruppin, F; Savini, G; Schuster, K; Sievers, A; Triqueneaux, S; Tucker, C; Zilch, R

    2016-01-01

    NIKA2 (New IRAM KID Arrays) is a dual band (150 and 260 GHz) imaging camera based on Kinetic Inductance Detectors (KIDs) and designed to work at the IRAM 30 m telescope (Pico Veleta, Spain). Built on the experience of the NIKA prototype, NIKA2 has been installed at the 30 m focal plane in October 2015 and the commissioning phase is now ongoing. Through the thermal Sunyaev-Zeldovich (tSZ) effect, NIKA2 will image the ionized gas residing in clusters of galaxies with a resolution of 12 and 18 arcsec FWHM (at 150 and 260 GHz, respectively). We report on the recent tSZ measurements with the NIKA camera and discuss the future objectives for the NIKA2 SZ large Program, 300h of observation dedicated to SZ science. With this program we intend to perform a high angular resolution follow-up of a cosmologically-representative sample of clusters belonging to SZ catalogues, with redshift greater than 0.5. The main output of the program will be the study of the redshift evolution of the cluster pressure profile as well as ...

  2. High Angular Resolution Stellar Imaging with Occultations from the Cassini Spacecraft I: Observational Technique

    CERN Document Server

    Stewart, Paul N; Hedman, Matthew M; Nicholson, Philip D; Lloyd, James P

    2013-01-01

    We present novel observations utilising the Cassini spacecraft to conduct an observing campaign for stellar astronomy from a vantage point in the outer solar system. By exploiting occultation events in which Mira passed behind the Saturnian ring plane as viewed by Cassini, parametric imaging data were recovered spanning the near-infrared. From this, spatial information at extremely high angular resolution was recovered enabling a study of the stellar atmospheric extension across a spectral bandpass spanning the 1 - 5 {\\mu}m spectral region in the near-infrared. The resulting measurements of the angular diameter of Mira were found to be consistent with existing observations of its variation in size with wavelength. The present study illustrates the validity of the technique; more detailed exploration of the stellar physics obtained by this novel experiment will be the subject of forthcoming papers.

  3. High Angular Resolution Observations of Four Candidate BLAST High-Mass Starless Cores

    CERN Document Server

    Olmi, Luca; Chapin, Edward L; Gibb, Andrew; Hofner, Peter; Martin, Peter G; Poventud, Carlos M

    2010-01-01

    We discuss high-angular resolution observations of ammonia toward four candidate high-mass starless cores (HMSCs). The cores were identified by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) during its 2005 survey of the Vulpecula region where 60 compact sources were detected simultaneously at 250, 350, and 500 micron. Four of these cores, with no IRAS-PSC or MSX counterparts, were observed with the NRAO Very Large Array (VLA) in the NH3(1,1) and (2,2) spectral lines. Our observations indicate that the four cores are cold (Tk <~ 14K) and show a filamentary and/or clumpy structure. They also show a significant velocity substructure within ~1km/s. The four BLAST cores appear to be colder and more quiescent than other previously observed HMSC candidates, suggesting an earlier stage of evolution.

  4. The Evershed effect observed with 0.2 arsec angular resolution

    CERN Document Server

    Almeida, J S; Bonet, J A; Cerdena, I D

    2006-01-01

    We present an analysis of the Evershed effect observed with a resolution of 0.2 arcsec. Using the new Swedish 1-m Solar Telescope and its Littrow spectrograph, we scan a significant part of a sunspot penumbra. Spectra of the non-magnetic line Fe I 7090.4 A allows us to measure Doppler shifts without magnetic contamination. The observed line profiles are asymmetric. The Doppler shift depends on the part of the line used for measuring, indicating that the velocity structure of penumbrae remains unresolved even with our angular resolution. The observed line profiles are properly reproduced if two components with velocities between zero and several km/s co-exist in the resolution elements. Using Doppler shifts at fixed line depths, we find a local correlation between upflows and bright structures, and downflows and dark structures. This association is not specific of the outer penumbra but it also occurs in the inner penumbra. The existence of such correlation was originally reported by Beckers & Schroter (19...

  5. Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection

    Science.gov (United States)

    Sana, H.; Le Bouquin, J.-B.; Lacour, S.; Berger, J.-P.; Duvert, G.; Gauchet, L.; Norris, B.; Olofsson, J.; Pickel, D.; Zins, G.; Absil, O.; de Koter, A.; Kratter, K.; Schnurr, O.; Zinnecker, H.

    2014-11-01

    Multiplicity is one of the most fundamental observable properties of massive O-type stars and offers a promising way to discriminate between massive star formation theories. Nevertheless, companions at separations between 1 and 100 milliarcsec (mas) remain mostly unknown due to intrinsic observational limitations. At a typical distance of 2 kpc, this corresponds to projected physical separations of 2-200 AU. The Southern MAssive Stars at High angular resolution survey (SMaSH+) was designed to fill this gap by providing the first systematic interferometric survey of Galactic massive stars. We observed 117 O-type stars with VLTI/PIONIER and 162 O-type stars with NACO/Sparse Aperture Masking (SAM), probing the separation ranges 1-45 and 30-250 mas and brightness contrasts of ΔH radio emitters observed by SMaSH+ are all resolved, including the newly discovered pairs HD 168112 and CPD-47°2963. This lends strong support to the universality of the wind-wind collision scenario to explain the non-thermal emission from O-type stars.

  6. Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection

    CERN Document Server

    Sana, H; Lacour, S; Berger, J -P; Duvert, G; Gauchet, L; Norris, B; Olofsson, J; Pickel, D; Zins, G; Absil, O; de Koter, A; Kratter, K; Schnurr, O; Zinnecker, H

    2014-01-01

    Multiplicity is one of the most fundamental observable properties of massive O-type stars and offers a promising way to discriminate between massive star formation theories. Nevertheless, companions at separations between 1 and 100 mas remain mostly unknown due to intrinsic observational limitations. [...] The Southern MAssive Stars at High angular resolution survey (SMASH+) was designed to fill this gap by providing the first systematic interferometric survey of Galactic massive stars. We observed 117 O-type stars with VLTI/PIONIER and 162 O-type stars with NACO/SAM, respectively probing the separation ranges 1-45 and 30-250mas and brightness contrasts of Delta H < 4 and Delta H < 5. Taking advantage of NACO's field-of-view, we further uniformly searched for visual companions in an 8''-radius down to Delta H = 8. This paper describes the observations and data analysis, reports the discovery of almost 200 new companions in the separation range from 1mas to 8'' and presents the catalog of detections, inc...

  7. High angular resolution observations towards OMC-2 FIR 4: Dissecting an intermediate-mass protocluster

    CERN Document Server

    López-Sepulcre, A; Sánchez-Monge, Á; Ceccarelli, C; Dominik, C; Kama, M; Caux, E; Fontani, F; Fuente, A; Ho, P T P; Neri, R; Shimajiri, Y

    2013-01-01

    OMC-2 FIR 4 is one of the closest known young intermediate-mass protoclusters, located at a distance of 420 pc in Orion. This region is one of the few where the complete 500-2000 GHz spectrum has been observed with the heterodyne spectrometer HIFI on board the Herschel satellite, and unbiased spectral surveys at 0.8, 1, 2 and 3 mm have been obtained with the JCMT and IRAM 30-m telescopes. In order to investigate the morphology of this region, we used the IRAM Plateau de Bure Interferometer to image OMC-2 FIR 4 in the 2-mm continuum emission, as well as in DCO+(2-1), DCN(2-1), C34S(3-2), and several CH3OH lines. In addition, we analysed observations of the NH3(1,1) and (2,2) inversion transitions made with the Very Large Array of the NRAO. The resulting maps have an angular resolution which allows us to resolve structures of 5", equivalent to 2000 AU. Our observations reveal three spatially resolved sources within OMC-2 FIR 4, of one or several solar masses each, with hints of further unresolved substructure w...

  8. First Results from High Angular Resolution ALMA Observations Toward the HL Tau Region

    CERN Document Server

    Partnership, ALMA; Perez, L M; Hunter, T R; Dent, W R F; Hales, A S; Hills, R; Corder, S; Fomalont, E B; Vlahakis, C; Asaki, Y; Barkats, D; Hirota, A; Hodge, J A; Impellizzeri, C M V; Kneissl, R; Liuzzo, E; Lucas, R; Marcelino, N; Matsushita, S; Nakanishi, K; Phillips, N; Richards, A M S; Toledo, I; Aladro, R; Broguiere, D; Cortes, J R; Cortes, P C; Dhawan, V; Espada, D; Galarza, F; Garcia-Appadoo, D; Guzman-Ramirez, L; Humphreys, E M; Jung, T; Kameno, S; Laing, R A; Leon, S; Marconi, G; Nikolic, B; Nyman, L -A; Radiszcz, M; Remijan, A; Rodon, J A; Sawada, T; Takahashi, S; Tilanus, R P J; Vilaro, B Vila; Watson, L C; Wiklind, T; Akiyama, E; Chapillon, E; de Gregorio, I; Di Francesco, J; Gueth, F; Kawamura, A; Lee, C -F; Luong, Q Nguyen; Mangum, J; Pietu, V; Sanhueza, P; Saigo, K; Takakuwa, S; Ubach, C; van Kempen, T; Wootten, A; Castro-Carrizo, A; Francke, H; Gallardo, J; Garcia, J; Gonzalez, S; Hill, T; Kaminski, T; Kurono, Y; Liu, H -Y; Lopez, C; Morales, F; Plarre, K; Schieven, G; Testi, L; Videla, L; Villard, E; Andreani, P; Hibbard, J E; Tatematsu, K

    2015-01-01

    We present Atacama Large Millimeter/submillimeter Array (ALMA) observations from the 2014 Long Baseline Campaign in dust continuum and spectral line emission from the HL Tau region. The continuum images at wavelengths of 2.9, 1.3, and 0.87 mm have unprecedented angular resolutions of 0.075 arcseconds (10 AU) to 0.025 arcseconds (3.5 AU), revealing an astonishing level of detail in the circumstellar disk surrounding the young solar analogue HL Tau, with a pattern of bright and dark rings observed at all wavelengths. By fitting ellipses to the most distinct rings, we measure precise values for the disk inclination (46.72pm0.05 degrees) and position angle (+138.02pm0.07 degrees). We obtain a high-fidelity image of the 1.0 mm spectral index ($\\alpha$), which ranges from $\\alpha\\sim2.0$ in the optically-thick central peak and two brightest rings, increasing to 2.3-3.0 in the dark rings. The dark rings are not devoid of emission, we estimate a grain emissivity index of 0.8 for the innermost dark ring and lower for ...

  9. High-angular resolution observations towards OMC-2 FIR 4: Dissecting an intermediate-mass protocluster

    Science.gov (United States)

    López-Sepulcre, A.; Taquet, V.; Sánchez-Monge, Á.; Ceccarelli, C.; Dominik, C.; Kama, M.; Caux, E.; Fontani, F.; Fuente, A.; Ho, P. T. P.; Neri, R.; Shimajiri, Y.

    2013-08-01

    Context. Intermediate-mass stars are an important ingredient of our Galaxy and a key to understanding how high- and low-mass stars form in clusters. One of the closest known young intermediate-mass protoclusters is OMC-2 FIR 4, which is located at a distance of 420 pc in Orion. This region is one of the few where the complete 500-2000 GHz spectrum has been observed with the heterodyne spectrometer HIFI on board the Herschel satellite, and unbiased spectral surveys at 0.8, 1, 2, and 3 mm have been obtained with the JCMT and IRAM 30-m telescopes. Aims: We aim to disentangle the core multiplicity, to investigate the morphology of this region in order to study the formation of a low- and intermediate-mass protostar cluster, and to aid in interpretation of the single-dish line profiles already in our hands. Methods: We used the IRAM Plateau de Bure Interferometer to image OMC-2 FIR 4 in the 2-mm continuum emission, as well as in DCO+(2-1), DCN(2-1), C34S(3-2), and several CH3OH lines. In addition, we analysed observations of the NH3(1, 1) and (2, 2) inversion transitions that used the Very Large Array of the NRAO. The resulting maps have an angular resolution that allows us to resolve structures of 5″, which is equivalent to ~2000 AU. Results: Our observations reveal three spatially resolved sources within OMC-2 FIR 4, of one or several solar masses each, with hints of further unresolved substructure within them. Two of these sources have elongated shapes and are associated with dust continuum emission peaks, thus likely containing at least one molecular core each. One of them also displays radio continuum emission, which may be attributed to a young B3-B4 star that dominates the overall luminosity output of the region. The third identified source displays a DCO+(2-1) emission peak and weak dust continuum emission. Its higher abundance of DCO+ relative to the other two regions suggests a lower temperature, hence its possible association with either a younger low

  10. Milliarcsecond angular resolution of reddened stellar sources in the vicinity of the Galactic Center. II. Additional observations

    CERN Document Server

    Richichi, A; Mason, E

    2008-01-01

    We present lunar occultation observations obtained in August 2006 with the recently demonstrated burst mode of the ISAAC instrument at the ESO VLT. The results presented here follow the previously reported observations carried out in March 2006 on a similar but unrelated set of sources. Interstellar extinction in the inner regions of the galactic bulge amounts to tens of magnitudes at visual wavelengths. As a consequence, the majority of sources in that area are poorly studied and large numbers of potentially interesting sources such as late-type giants with circumstellar shells, stellar masers, infrared stars, remain excluded from the typical investigations which are carried out in less problematic regions. Also undetected are a large numbers of binaries. By observing LO events in this region, we gain the means to investigate at least a selected number of sources with an unprecedented combination of sensitivity and angular resolution. The LO technique permits to achieve mas resolution with a sensitivity of K...

  11. Atmospheric Phase Correction using CARMA-PACS: High Angular Resolution Observations of the FU-Orionis star PP 13S*

    CERN Document Server

    Pérez, Laura M; Woody, David P; Carpenter, John M; Zauderer, B Ashley; Isella, Andrea; Bock, Douglas C; Bolatto, Alberto D; Carlstrom, John; Culverhouse, Thomas L; Joy, Marshall; Kwon, Woojin; Leitch, Erik M; Marrone, Daniel P; Muchovej, Stephen J; Plambeck, Richard L; Scott, Stephen L; Teuben, Peter J; Wright, Melvyn C H

    2010-01-01

    We present 0.15" resolution observations of the 227 GHz continuum emission from the circumstellar disk around the FU-Orionis star PP 13S*. The data were obtained with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) Paired Antenna Calibration System (C-PACS), which measures and corrects the atmospheric delay fluctuations on the longest baselines of the array in order to improve the sensitivity and angular resolution of the observations. A description of the C-PACS technique and the data reduction procedures are presented. C-PACS was applied to CARMA observations of PP 13S*, which led to a factor of 1.6 increase in the observed peak flux of the source, a 36% reduction in the noise of the image, and a 52% decrease in the measured size of the source major axis. The calibrated complex visibilities were fitted with a theoretical disk model to constrain the disk surface density. The total disk mass from the best fit model corresponds to 0.06 \\msun, which is larger than the median mass of a disk ...

  12. Low-Frequency Radio Observations of the Solar Corona with Arcminute Angular Resolution: Implications for Coronal Turbulence and Weak Energy Releases

    Science.gov (United States)

    Mugundhan, V.; Ramesh, R.; Barve, Indrajit V.; Kathiravan, C.; Gireesh, G. V. S.; Kharb, P.; Misra, Apurva

    2016-11-01

    We report on the first long baseline interferometer (length ≈8 km) observations of the solar corona at 37 MHz that were carried out recently with an angular resolution of ≈ {1}\\prime . The results indicate that, (1) discrete radio sources of the aforesaid angular size or even lesser are present in the solar corona from where radiation at the above frequency originates. This constrains the angular broadening of radio sources at low frequencies due to scattering by density turbulence in the solar corona; and (2) the observed sources in the present case correspond to the weakest energy releases in the solar atmosphere reported so far.

  13. High angular resolution Sunyaev-Zel'dovich observations of MACS J1423.8+2404 with NIKA: multi-wavelength analysis

    CERN Document Server

    Adam, R; Bartalucci, I; Adane, A; Ade, P; André, P; Arnaud, M; Beelen, A; Belier, B; Benoît, A; Bideaud, A; Billot, N; Bourrion, O; Calvo, M; Catalano, A; Coiffard, G; D'Addabbo, A; Désert, F -X; Doyle, S; Goupy, J; Hasnoun, B; Hermelo, I; Kramer, C; Lagache, G; Leclercq, S; Macías-Pérez, J -F; Martino, J; Mauskopf, P; Mayet, F; Monfardini, A; Pajot, F; Pascale, E; Perotto, L; Pointecouteau, E; Ponthieu, N; Pratt, G W; Revéret, V; Ritacco, A; Rodriguez, L; Savini, G; Schuster, K; Sievers, A; Triqueneaux, S; Tucker, C; Zylka, R

    2015-01-01

    NIKA, the prototype of the NIKA2 camera, is an instrument operating at the IRAM 30m telescope that can observe the sky simultaneously at 150 and 260GHz. One of the main goals of NIKA is to measure the pressure distribution in galaxy clusters at high angular resolution using the Sunyaev-Zel'dovich (SZ) effect. Such observations have already proved to be an excellent probe of cluster pressure distributions even at high redshifts. However, an important fraction of clusters host submm and/or radio point sources that can significantly affect the reconstructed signal. Here we report <20arcsec angular resolution observations at 150 and 260GHz of the cluster MACSJ1424, which hosts both radio and submm point sources. We examine the morphological distribution of the SZ signal and compare it to other datasets. The NIKA data are combined with Herschel satellite data to study the SED of the submm point source contaminants. We then perform a joint reconstruction of the ICM electronic pressure and density by combining NI...

  14. Angular resolution of stacked resistive plate chambers

    CERN Document Server

    Samuel, Deepak; Murgod, Lakshmi P

    2016-01-01

    We present here detailed derivations of mathematical expressions for the angular resolution of a set of stacked resistive plate chambers (RPCs). The expressions are validated against experimental results using data collected from the prototype detectors (without magnet) of the upcoming India-based Neutrino Observatory (INO). In principle, these expressions can be used for any other detector with an architecture similar to that of RPCs.

  15. Systematics in Metallicity Gradient Measurements I : Angular Resolution, Signal-to-Noise and Annuli Binning

    CERN Document Server

    Yuan, T -T; Rich, J

    2013-01-01

    With the rapid progress in metallicity gradient studies at high-redshift, it is imperative that we thoroughly understand the systematics in these measurements. This work investigates how the [NII]/Halpha ratio based metallicity gradients change with angular resolution, signal-to-noise (S/N), and annular binning parameters. Two approaches are used: 1. We downgrade the high angular resolution integral-field data of a gravitationally lensed galaxy and re-derive the metallicity gradients at different angular resolution; 2. We simulate high-redshift integral field spectroscopy (IFS) observations under different angular resolution and S/N conditions using a local galaxy with a known gradient. We find that the measured metallicity gradient changes systematically with angular resolution and annular binning. Seeing-limited observations produce significantly flatter gradients than higher angular resolution observations. There is a critical angular resolution limit beyond which the measured metallicity gradient is subst...

  16. Direct observation of strain in bulk subgrains and dislocation walls by high angular resolution three-dimensional X-ray diffraction

    DEFF Research Database (Denmark)

    Jakobsen, Bo; Lienert, U.; Almer, J.;

    2008-01-01

    The X-ray diffraction (XRD) method "high angular resolution 3DXRD" is briefly introduced, and results are presented for a single bulk grain in a polycrystalline copper sample deformed in tension. It is found that the three-dimensional reciprocal-space intensity distribution of a 400 reflection...

  17. First VLTI infrared spectro-interferometry on GCIRS 7 - Characterizing the prime reference source for Galactic center observations at highest angular resolution

    CERN Document Server

    Pott, J -U; Glindemann, A; Kraus, S; Schödel, R; Ghez, A M; Woillez, J; Weigelt, G

    2008-01-01

    Investigating the environment of the massive black hole SgrA* at the center of the Galaxy requires the highest angular resolution available to avoid source confusion and to study the physical properties of the individual objects. GCIRS7 has been used as wavefront and astrometric reference. Our studies investigate, for the first time, its properties at 2&10um using VLTI/AMBER and MIDI. We aim at analyzing the suitability of IRS7 as an IF-phase-reference for the upcoming generation of dual-field facilities at optical interferometers. We observed with (R~30) and 50m (proj.) baseline, resulting in 9 and 45mas resolution for NIR and MIR, resp. The first K-band fringe detection of a GC star suggests that IRS7 could be marginally resolved at 2um, which would imply that the photosphere of the supergiant is enshrouded by a molecular and dusty envelope. At 10um, IRS7 is strongly resolved with a visibility of approximately 0.2. The MIR is dominated by moderately warm (200 K), extended dust, mostly distributed outsid...

  18. High Angular Resolution Observations of Episodic Dust Emission from Long Period Variable Stars Twenty Years of Observations with the Berkeley Infrared Spatial Interferometer

    Science.gov (United States)

    Danchi, William

    2010-01-01

    Over the past twenty years the U. C. Berkeley Infrared Spatial Interferometer has observed a number of Long Period Variable stars in the mid-infrared, obtaining information on the spatial distribution of dust around these stars with resolutions of the order of a few tens of milliarcseconds. The ISI is a heterodyne interferometer operating mostly at 11.15 microns, initially with two telescopes. In the last decade, it has been taking data regularly with three telescopes, thus obtaining visibility data on three baselines and also a closure phase. Over the course of the years, the ISI has been able to measure the physical properties of the dust shells surrounding these stars, in particular the inner radii of the dust shells, as well as the temperature and density distribution. For some stars, the ISI has also made precision measurements of their diameters in the mid-infrared. Closure phase measurements have revealed asymmetries in the dust distributions around many stars. Most surprisingly the ISI data has shown evidence for substantial changes in the amount of dust on time scales of 5-10 years, rather than being directly correlated with the stellar pulsation periods, which are of the order of one year. We discuss past results and new results from the ISI that highlight the dynamic environment around these stars.

  19. Higher signal harmonics, LISA's angular resolution and dark energy

    CERN Document Server

    Arun, K G; Sathyaprakash, B S; Sinha, Siddhartha; Broeck, Chris Van Den

    2007-01-01

    It is generally believed that the angular resolution of the Laser Interferometer Space Antenna (LISA) for binary supermassive black holes (SMBH) will not be good enough to identify the host galaxy or galaxy cluster. This conclusion, based on using only the dominant harmonic of the binary SMBH signal, changes dramatically when higher signal harmonics are included in assessing the parameter estimation problem. We show that in a subset of the source parameter space the angular resolution increases by more than a factor of 10, thereby making it possible for LISA to identify the host galaxy/galaxy cluster. Thus, LISA's observation of certain binary SMBH coalescence events could constrain the dark energy equation of state to within a few percent, comparable to the level expected from other dark energy missions.

  20. Towards optical intensity interferometry for high angular resolution stellar astrophysics

    CERN Document Server

    Nunez, Paul D

    2012-01-01

    Most neighboring stars are still detected as point sources and are beyond the angular resolution reach of current observatories. Methods to improve our understanding of stars at high angular resolution are investigated. Air Cherenkov telescopes (ACTs), primarily used for Gamma-ray astronomy, enable us to increase our understanding of the circumstellar environment of a particular system. When used as optical intensity interferometers, future ACT arrays will allow us to detect stars as extended objects and image their surfaces at high angular resolution. Optical stellar intensity interferometry (SII) with ACT arrays, composed of nearly 100 telescopes, will provide means to measure fundamental stellar parameters and also open the possibility of model-independent imaging. A data analysis algorithm is developed and permits the reconstruction of high angular resolution images from simulated SII data. The capabilities and limitations of future ACT arrays used for high angular resolution imaging are investigated via ...

  1. Statistical Angular Resolution Limit for Ultrawideband MIMO Noise Radar

    OpenAIRE

    2015-01-01

    The two-dimensional angular resolution limit (ARL) of elevation and azimuth for MIMO radar with ultrawideband (UWB) noise waveforms is investigated using statistical resolution theory. First, the signal model of monostatic UWB MIMO noise radar is established in a 3D reference frame. Then, the statistical angular resolution limits (SARLs) of two closely spaced targets are derived using the detection-theoretic and estimation-theoretic approaches, respectively. The detection-theoretic approach i...

  2. Observing and modeling the dynamic atmosphere of the low mass-loss C-star R Sculptoris at high angular resolution

    CERN Document Server

    Sacuto, Stéphane; Hron, Josef; Nowotny, Walter; Paladini, Claudia; Verhoelst, Tijl; Höfner, Susanne

    2010-01-01

    We study the circumstellar environment of the carbon-rich star R Scl using the near- and mid-infrared high spatial resolution observations from the ESO-VLTI instruments VINCI and MIDI. These observations aim at increasing our knowledge of the dynamic processes in play within the very close circumstellar environment where the mass loss of AGB stars is initiated. Data are interpreted using a self-consistent dynamic model. Interferometric observations do not show any significant variability effect at the 16 m baseline between phases 0.17 and 0.23 in the K band, and for both the 15 m baseline between phases 0.66 and 0.97 and the 31 m baseline between phases 0.90 and 0.97 in the N band. We find fairly good agreement between the dynamic model and the spectrophotometric data from 0.4 to 25 $\\mu$m. The model agrees well with the time-dependent flux data at 8.5 $\\mu$m, whereas it is too faint at 11.3 and 12.5 $\\mu$m. The VINCI visibilities are reproduced well, meaning that the extension of the model is suitable in the...

  3. Progress Toward A Very High Angular Resolution Imaging Spectrometer (VERIS)

    Science.gov (United States)

    Korendyke, Clarence M.; Vourlidas, A.; Landi, E.; Seely, J.; Klimchuck, J.

    2007-07-01

    Recent imaging at arcsecond (TRACE) and sub-arcsecond (VAULT) spatial resolution clearly show that structures with fine spatial scales play a key role in the physics of the upper solar atmosphere. Both theoretical and observational considerations point to the importance of small spatial scales, impulsive energy release, strong dynamics, and extreme plasma nonuniformity. Fundamental questions regarding the nature, structure, properties and dynamics of loops and filamentary structures in the upper atmosphere have been raised. To address these questions, we are developing a next generation, VEry high angular Resolution Imaging Spectrometer (VERIS) as a sounding rocket instrument. VERIS will obtain the necessary high spatial resolution, high fidelity measurements of plasma temperatures, densities and velocities. With broad simultaneous temperature coverage, the VERIS observations will directly address unresolved issues relating to interconnections of various temperature solar plasmas. VERIS will provide the first ever subarcsecond spectra of transition region and coronal structures. It will do so with a sufficient spectral resolution of to allow centroided Doppler velocity determinations to better than 3 km/s. VERIS uses a novel two element, normal incidence optical design with highly reflective EUV coatings to access a spectral range with broad temperature coverage (0.03-15 MK) and density-sensitive line ratios. Finally, in addition to the spectra, VERIS will simultaneously obtain spectrally pure slot images (10x150 arcsec) in the +/-1 grating orders, which can be combined to make instantaneous line-of-sight velocity maps with 8km/s accuracy over an unprecedented field of view. The VERIS program is beginning the second year of its three year development cycle. All design activities and reviews are complete. Fabrication of all major components has begun. Brassboard electronics cards have been fabricated, assembled and tested. The paper presents the essential scientific

  4. Transient sources at the highest angular resolution

    CERN Document Server

    Massi, Maria

    2015-01-01

    By definition transients are sudden events, some, like supernovae, are catastrophic, while others might be due to recurrent phenomena. The aim of studying transients is to reveal the physical conditions causing them, in this sense ideal targets for monitoring are transients in binary systems. In these systems the physical process responsible for the transient depends directly or indirectly on the interaction of the two components of the system. Here I report on transients in stellar binary systems at two extremes of stellar evolution: a T~Tauri system formed by two young low mass stellar objects, and X-ray binary systems formed by a star and a neutron star or a black hole, i.e., end points in the life of massive stars. VLBI observations of the young binary system V773 Tau A resolve the binary separation and can be overlapped with the optical frame. Consecutive VLBI observations showing the evolution of the radio emission with respect to the two stellar objects are an unvaluable tool for a better understanding...

  5. Cepheids at high angular resolution: circumstellar envelope and pulsation

    CERN Document Server

    Gallenne, Alexandre

    2011-01-01

    In 2005, interferometric observations with VLTI/VINCI and CHARA/FLUOR revealed the existence of a circumstellar envelope (CSE) around some Cepheids. This surrounding material is particularly interesting for two reasons: it could have an impact on the distance estimates and could be linked to a past or on-going mass loss. The use of Baade-Wesselink methods for independent distance determinations could be significantly biased by the presence of these envelopes. Although their observations are difficult because of the high contrast between the photosphere of the star and the CSE, several observation techniques have the potential to improve our knowledge about their physical properties. In this thesis, I discuss in particular high angular resolution techniques that I applied to the study of several bright Galactic Cepheids. First, I used adaptive optic observations with NACO of the Cepheid RS Puppis, in order to deduce the flux ratio between the CSE and the photosphere of the star. In addition, I could carry out ...

  6. Cepheids at high angular resolution: circumstellar envelope and pulsation

    Science.gov (United States)

    Gallenne, Alexandre

    2011-12-01

    In 2005, interferometric observations with VLTI/VINCI and CHARA/FLUOR revealed the existence of a circumstellar envelope (CSE) around some Cepheids. This surrounding material is particularly interesting for two reasons: it could have an impact on the distance estimates and could be linked to a past or on-going mass loss. The use of Baade-Wesselink methods for independent distance determinations could be significantly biased by the presence of these envelopes. Although their observations are difficult because of the high contrast between the photosphere of the star and the CSE, several observation techniques have the potential to improve our knowledge about their physical properties. In this thesis, I discuss in particular high angular resolution techniques that I applied to the study of several bright Galactic Cepheids. First, I used adaptive optic observations with NACO of the Cepheid RS Puppis, in order to deduce the flux ratio between the CSE and the photosphere of the star. In addition, I could carry out a statistical study of the speckle noise and inspect a possible asymmetry. Secondly, I analysed VISIR data to study the spectral energy distribution of a sample of Cepheids. These diffraction-limited images enabled me to carry out an accurate photometry in the N band and to detect an IR excess linked to the presence of a circumstellar component. On the other hand, applying a Fourier analysis I showed that some components are resolved. I then explored the K' band with the recombination instrument FLUOR for some bright Cepheids. Thanks to new set of data of Y Oph, I improved the study of its circumstellar envelope, using a ring-like model for the CSE. For two other Cepheids, U Vul and S Sge, I applied the interferometric Baade-Wesselink method in order to estimate their distance.

  7. Statistical Angular Resolution Limit for Ultrawideband MIMO Noise Radar

    Directory of Open Access Journals (Sweden)

    Xiaoli Zhou

    2015-01-01

    Full Text Available The two-dimensional angular resolution limit (ARL of elevation and azimuth for MIMO radar with ultrawideband (UWB noise waveforms is investigated using statistical resolution theory. First, the signal model of monostatic UWB MIMO noise radar is established in a 3D reference frame. Then, the statistical angular resolution limits (SARLs of two closely spaced targets are derived using the detection-theoretic and estimation-theoretic approaches, respectively. The detection-theoretic approach is based on the generalized likelihood ratio test (GLRT with given probabilities of false alarm and detection, while the estimation-theoretic approach is based on Smith’s criterion which involves the Cramér-Rao lower bound (CRLB. Furthermore, the relationship between the two approaches is presented, and the factors affecting the SARL, that is, detection parameters, transmit waveforms, array geometry, signal-to-noise ratio (SNR, and parameters of target (i.e., radar cross section (RCS and direction, are analyzed. Compared with the conventional radar resolution theory defined by the ambiguity function, the SARL reflects the practical resolution ability of radar and can provide an optimization criterion for radar system design.

  8. Development of the super high angular resolution principle for X-ray imaging *

    Institute of Scientific and Technical Information of China (English)

    Chen Zhang; Shuang-Nan Zhang

    2011-01-01

    Development of the Super High Angular Resolution Principle (SHARP)for coded-mask X-ray imaging is presented. We prove that SHARP can be considered as a generalized coded mask imaging method with a coding pattern comprised of diffraction-interference fringes in the mask pattern. The angular resolution of SHARP can be improved by detecting the fringes more precisely than the mask's element size,i.e. by using a detector with a pixel size smaller than the mask's element size. The proposed mission SHARP-X for solar X-ray observations is also briefly discussed.

  9. Angular resolution study of a combined gamma-neutron coded aperture imager for standoff detection

    Science.gov (United States)

    Ayaz-Maierhafer, Birsen; Hayward, Jason P.; Ziock, Klaus P.; Blackston, Matthew A.; Fabris, Lorenzo

    2013-06-01

    Nuclear threat source observables at standoff distances of tens of meters from mCi class sources include both gamma-rays and neutrons. This work uses simulations to investigate the effects of the angular resolution of a mobile gamma-ray and neutron coded aperture imaging system upon orphan source detection significance and specificity. The design requires maintaining high sensitivity and specificity while keeping the system size as compact as possible to reduce weight, footprint, and cost. A mixture of inorganic and organic scintillators was considered in the detector plane for high sensitivity to both gamma-rays and fast neutrons. For gamma-rays (100 to 2500 keV) and fission spectrum neutrons, angular resolutions of 1-9° and radiation angles of incidence appropriate for mobile search were evaluated. Detection significance for gamma-rays considers those events that contribute to the photopeak of the image pixel corresponding the orphan source location. For detection of fission spectrum neutrons, energy depositions above a set pulse shape discrimination threshold were tallied. The results show that the expected detection significance for the system at an angular resolution of 1° is significantly lower compared to its detection significance an angular resolution of ˜3-4°. An angular resolution of ˜3-4° is recommended both for better detection significance and improved false alarm rate, considering that finer angular resolution does not result in improved background rejection when the coded aperture method is used. Instead, over-pixelating the search space may result in an unacceptably high false alarm rate.

  10. 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

    CERN Document Server

    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; Büchele, 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; Coffaro, 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; Dutson, K; Dyks, J; Edwards, T; Egberts, K; Eger, P; Ernenwein, J -P; Eschbach, S; Farnier, C; Fegan, S; Fern, M V; Fiasson, A; Fontaine, G; Förster, A; 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; 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; Mar, 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; de Naurois, M; 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; Reyes, R de los; Rieger, F; Romoli, C; 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; Seglar-Arroyo, L; 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; Stycz, K; Sushch, I; 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; van Eldik, C; van Rensburg, C; van Soelen, B; Vasileiadis, G; Veh, J; Venter, C; Viana, A; Vincent, P; Vink, J; Voisin, F; Völk, H J; 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; Zanin, R; Zdziarski, A A; Zech, A; Zefi, F; Ziegler, A; Żywucka, N

    2016-01-01

    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 $0.048^\\circ$ ($0.036^\\circ$ 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 u...

  11. Angular Resolution of the LISA Gravitational Wave Detector

    CERN Document Server

    Cutler, C

    1998-01-01

    We calculate the angular resolution of the planned LISA detector, a space-based laser interferometer for measuring low-frequency gravitational waves from galactic and extragalactic sources. LISA is not a pointed instrument; it is an all-sky monitor with a quadrupolar beam pattern. LISA will measure simultaneously both polarization components of incoming gravitational waves, so the data will consist of two time series. All physical properties of the source, including its position, must be extracted from these time series. LISA's angular resolution is therefore not a fixed quantity, but rather depends on the type of signal and on how much other information must be extracted. Information about the source position will be encoded in the measured signal in three ways: 1) through the relative amplitudes and phases of the two polarization components, 2) through the periodic Doppler shift imposed on the signal by the detector's motion around the Sun, and 3) through the further modulation of the signal caused by the d...

  12. A Role for Improved Angular Observations in Geosynchronous Orbit Determination

    Science.gov (United States)

    Sabol, Christopher Andrew

    1998-12-01

    The goal of this thesis is to show that improved angular observations can aid in the determination of satellite position and velocity in the geosynchronous orbit regime. Raven is a new sensor being developed by the U.S. Air Force Research Laboratory which should allow for angular observations of satellites to be made with a standard deviation of 1 arcsecond (which maps into approximately 170 meters at geosynchronous altitude); this is an order of magnitude improvement over traditional angular observation techniques and represents state of the art accuracy of angular observations for geosynchronous orbit determination work. Simulation studies are undertaken to show that these angular observations can be used in the orbit determination process both as the only cracking data source and as a supplement to other tracking data sources such as radar and radio transponder ranges. Results from the radio transponder range analysis are extended to cover Satellite Laser Ranging (SLR) and Global Positioning System (GPS) observation types as well. The studies target both space surveillance and owner/operator mission support aspects of orbit determination although the emphasis will be on mission support satellite operations. Parameters varied in the simulation studies include the number of observing stations, the density of the angular observations, and the number of nights of optical tracking. The data simulations are calibrated based on real data results from a geosynchronous satellite to ensure the integrity of the simulations and the accuracy of the results. The studies show that including the improved angular observations with traditional high accuracy range observations produces a significant improvement in orbit determination accuracy over the range observations alone. The studies also show single site geosynchronous orbit determination is an attractive alternative when combining improved angular and high accuracy range observations.

  13. High angular resolution diffusion imaging with stimulated echoes

    DEFF Research Database (Denmark)

    Lundell, Henrik; Alexander, Daniel C; Dyrby, Tim B

    2014-01-01

    other than the diffusion gradients in the STEAM sequence contribute much greater diffusion weighting than in PGSE and lead to a disrupted experimental design. Here, we introduce a simple compensation to the STEAM acquisition that avoids the orientational bias and disrupted experiment design...... that these gradient pulses can otherwise produce. The compensation is simple to implement by adjusting the gradient vectors in the diffusion pulses of the STEAM sequence, so that the net effective gradient vector including contributions from diffusion and other gradient pulses is as the experiment intends. High...... angular resolution diffusion imaging (HARDI) data were acquired with and without the proposed compensation. The data were processed to derive standard diffusion tensor imaging (DTI) maps, which highlight the need for the compensation. Ignoring the other gradient pulses, a bias in DTI parameters from STEAM...

  14. Extracting Angular Observables without a Likelihood and Applications to Rare Decays

    CERN Document Server

    Beaujean, Frederik; Serra, Nicola; van Dyk, Danny

    2015-01-01

    Our goal is to obtain a complete set of angular observables arising in a generic multi-body process. We show how this can be achieved without the need to carry out a likelihood fit of the angular distribution to the measured events. Instead, we apply the method of moments that relies both on the orthogonality of angular functions and the estimation of integrals by Monte Carlo techniques. The big advantage of this method is that the joint distribution of all observables can be easily extracted, even for very few events. The method of moments is shown to be robust against mismodeling of the angular distribution. Our main result is an explicit algorithm that accounts for systematic uncertainties from detector-resolution and acceptance effects. Finally, we present the necessary process-dependent formulae needed for direct application of the method to several rare decays of interest.

  15. Improving the Angular Resolution of Coded-Mask Telescopes by Direct Demodulation

    Institute of Scientific and Technical Information of China (English)

    Zong-Jun Shen; Jian-Feng Zhou

    2008-01-01

    We develop a new procedure to improve the angular resolution of coded-mask telescopes by the Direct Demodulation Method (DDM). DDM has been applied to both real and simulated data of INTEGRAL/IBIS. The angular resolution of IBIS/ISGRI has been improved from about 13' to 2'.

  16. High Angular Resolution and Lightweight X-Ray Optics for Astronomical Missions

    Science.gov (United States)

    Zhang, W. W.; Biskach, M. P.; Blake, P. N.; Chan, K. W.; Evans, T. C.; Hong, M.; Jones, W. D.; Jones, W. D.; Kolos, L. D.; Mazzarella, J. M.; McClelland, R. S.; ODell, S. L.; Saha, T. T.; Sharpe, M. V.

    2011-01-01

    X-ray optics with both high angular resolution and lightweight is essential for further progress in x-ray astronomy. High angular resolution is important in avoiding source confusion and reducing background to enable the observation of the most distant objects of the early Universe. It is also important in enabling the use of gratings to achieve high spectral resolution to study, among other things, the myriad plasmas that exist in planetary, stellar, galactic environments, as well as interplanetary, inter-stellar, and inter-galactic media. Lightweight is important for further increase in effective photon collection area, because x-ray observations must take place on space platforms and the amount of mass that can be launched into space has always been very limited and is expected to continue to be very limited. This paper describes an x-ray optics development program and reports on its status that meets these two requirements. The objective of this program is to enable Explorer type missions in the near term and to enable flagship missions in the long term.

  17. Multiwavelength fiber lasers based on spatial mode beating for high resolution linear and angular displacement sensing

    Science.gov (United States)

    Chen, Nan-Kuang; Chang, Yung-Hsiang; Cheng, Wood-Hi; Guo, Tuan; Guan, Bai-Ou

    2014-05-01

    We demonstrate multiwavelength fiber lasers by incorporating the micro Michelson interferometer with spatial mode beating phenomenon, which comes from the interferences among cladding modes, into ring cavity for high resolution linear and angular displacement sensing.

  18. Understanding Active Galactic Nuclei using near-infrared high angular resolution polarimetry II: Preliminary results

    Science.gov (United States)

    Marin, F.; Grosset, L.; Goosmann, R.; Gratadour, D.; Rouan, D.; Clénet, Y.; Pelat, D.; Rojas Lobos, P. A.

    2016-12-01

    In this second research note of a series of two, we present the first near-infrared results we obtained when modeling Active Galactic Nuclei (AGN). Our first proceedings showed the comparison between the MontAGN and STOKES Monte Carlo codes. Now we use our radiative transfer codes to simulate the polarization maps of a prototypical, NGC 1068-like, type-2 radio-quiet AGN. We produced high angular resolution infrared (1 μm) polarization images to be compared with recent observations in this wavelength range. Our preliminary results already show a good agreement between the models and observations but cannot account for the peculiar linear polarization angle of the torus such as observed. tet{Gratadour2015} found a polarization position angle being perpendicular to the bipolar outflows axis. Further work is needed to improve the models by adding physical phenomena such as dichroism and clumpiness.

  19. Understanding Active Galactic Nuclei using near-infrared high angular resolution polarimetry II: Preliminary results

    CERN Document Server

    Marin, F; Goosmann, R; Gratadour, D; Rouan, D; Clénet, Y; Pelat, D; Lobos, P Andrea Rojas

    2016-01-01

    In this second research note of a series of two, we present the first near-infrared results we obtained when modeling Active Galactic Nuclei (AGN). Our first proceedings showed the comparison between the MontAGN and STOKES Monte Carlo codes. Now we use our radiative transfer codes to simulate the polarization maps of a prototypical, NGC 1068-like, type-2 radio-quiet AGN. We produced high angular resolution infrared (1 micron) polarization images to be compared with recent observations in this wavelength range. Our preliminary results already show a good agreement between the models and observations but cannot account for the peculiar linear polarization angle of the torus such as observed. Gratadour et al. 2015 found a polarization position angle being perpendicular to the bipolar outflows axis. Further work is needed to improve the models by adding physical phenomena such as dichroism and clumpiness.

  20. Improving the H.E.S.S. angular resolution using the Disp method

    CERN Document Server

    Lu, C -C

    2013-01-01

    The angular resolution of imaging atmospheric Cherenkov telescopes depends on the employed event reconstruction methods. By taking the weighted average of intersections of shower axes, the H.E.S.S. experiment achieves a 0.08 degree angular resolution at 20 degree zenith angle with an image size cut of 160 p.e. for sources with a spectral index of 2. However, the angular resolution degrades to 0.14 degree at 60 degree zenith angle, due to the larger fraction of nearly parallel images. The Disp method reduces the impact of parallel images by including an estimation of the image displacement (disp), inferred from the Hillas parameters, in the reconstruction procedure. By using this technique, the angular resolution at large zenith angles can be improved by 50%. An additional cut on the estimated direction uncertainty can further improve the angular resolution to around 0.05 degrees at the expense of a loss of 50% of effective area. The performance of this reconstruction method on simulated gamma-ray events and r...

  1. The Multiplicity of Massive Stars: A High Angular Resolution Survey With The HST Fine Guidance Sensor

    Science.gov (United States)

    2015-01-01

    to their place of birth have relatively more companions, consistent with the idea that stars ejected from clusters are preferentially single objects...THE MULTIPLICITY OF MASSIVE STARS : A HIGH ANGULAR RESOLUTION SURVEY WITH THE HST FINE GUIDANCE SENSOR* E. J. Aldoretta1,2, S. M. Caballero-Nieves3, D...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

  2. High-Angular-Resolution and High-Sensitivity Science Enabled by Beamformed ALMA

    CERN Document Server

    Fish, Vincent; Anderson, James; Asada, Keiichi; Baudry, Alain; Broderick, Avery; Carilli, Chris; Colomer, Francisco; Conway, John; Dexter, Jason; Doeleman, Sheperd; Eatough, Ralph; Falcke, Heino; Frey, Sándor; Gabányi, Krisztina; Gálvan-Madrid, Roberto; Gammie, Charles; Giroletti, Marcello; Goddi, Ciriaco; Gómez, Jose L; Hada, Kazuhiro; Hecht, Michael; Honma, Mareki; Humphreys, Elizabeth; Impellizzeri, Violette; Johannsen, Tim; Jorstad, Svetlana; Kino, Motoki; Körding, Elmar; Kramer, Michael; Krichbaum, Thomas; Kudryavtseva, Nadia; Laing, Robert; Lazio, Joseph; Loeb, Abraham; Lu, Ru-Sen; Maccarone, Thomas; Marscher, Alan; Mart'ı-Vidal, Iván; Martins, Carlos; Matthews, Lynn; Menten, Karl; Miller, Jon; Miller-Jones, James; Mirabel, Félix; Muller, Sebastien; Nagai, Hiroshi; Nagar, Neil; Nakamura, Masanori; Paragi, Zsolt; Pradel, Nicolas; Psaltis, Dimitrios; Ransom, Scott; Rodr'\\iguez, Luis; Rottmann, Helge; Rushton, Anthony; Shen, Zhi-Qiang; Smith, David; Stappers, Benjamin; Takahashi, Rohta; Tarchi, Andrea; Tilanus, Remo; Verbiest, Joris; Vlemmings, Wouter; Walker, R Craig; Wardle, John; Wiik, Kaj; Zackrisson, Erik; Zensus, J Anton

    2013-01-01

    An international consortium is presently constructing a beamformer for the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile that will be available as a facility instrument. The beamformer will aggregate the entire collecting area of the array into a single, very large aperture. The extraordinary sensitivity of phased ALMA, combined with the extremely fine angular resolution available on baselines to the Northern Hemisphere, will enable transformational new very long baseline interferometry (VLBI) observations in Bands 6 and 7 (1.3 and 0.8 mm) and provide substantial improvements to existing VLBI arrays in Bands 1 and 3 (7 and 3 mm). The ALMA beamformer will have impact on a variety of scientific topics, including accretion and outflow processes around black holes in active galactic nuclei (AGN), tests of general relativity near black holes, jet launch and collimation from AGN and microquasars, pulsar and magnetar emission processes, the chemical history of the universe and the evolution of fundame...

  3. Non-Parametric Tests of Structure for High Angular Resolution Diffusion Imaging in Q-Space

    CERN Document Server

    Olhede, Sofia C

    2010-01-01

    High angular resolution diffusion imaging data is the observed characteristic function for the local diffusion of water molecules in tissue. This data is used to infer structural information in brain imaging. Non-parametric scalar measures are proposed to summarize such data, and to locally characterize spatial features of the diffusion probability density function (PDF), relying on the geometry of the characteristic function. Summary statistics are defined so that their distributions are, to first order, both independent of nuisance parameters and also analytically tractable. The dominant direction of the diffusion at a spatial location (voxel) is determined, and a new set of axes are introduced in Fourier space. Variation quantified in these axes determines the local spatial properties of the diffusion density. Non-parametric hypothesis tests for determining whether the diffusion is unimodal, isotropic or multi-modal are proposed. More subtle characteristics of white-matter microstructure, such as the degre...

  4. Bayesian Deconvolution for Angular Super-Resolution in Forward-Looking Scanning Radar

    Directory of Open Access Journals (Sweden)

    Yuebo Zha

    2015-03-01

    Full Text Available Scanning radar is of notable importance for ground surveillance, terrain mapping and disaster rescue. However, the angular resolution of a scanning radar image is poor compared to the achievable range resolution. This paper presents a deconvolution algorithm for angular super-resolution in scanning radar based on Bayesian theory, which states that the angular super-resolution can be realized by solving the corresponding deconvolution problem with the maximum a posteriori (MAP criterion. The algorithm considers that the noise is composed of two mutually independent parts, i.e., a Gaussian signal-independent component and a Poisson signal-dependent component. In addition, the Laplace distribution is used to represent the prior information about the targets under the assumption that the radar image of interest can be represented by the dominant scatters in the scene. Experimental results demonstrate that the proposed deconvolution algorithm has higher precision for angular super-resolution compared with the conventional algorithms, such as the Tikhonov regularization algorithm, the Wiener filter and the Richardson–Lucy algorithm.

  5. Chiral resolution of spin angular momentum in linearly polarized and unpolarized light.

    Science.gov (United States)

    Hernández, R J; Mazzulla, A; Provenzano, C; Pagliusi, P; Cipparrone, G

    2015-11-20

    Linearly polarized (LP) and unpolarized (UP) light are racemic entities since they can be described as superposition of opposite circularly polarized (CP) components of equal amplitude. As a consequence they do not carry spin angular momentum. Chiral resolution of a racemate, i.e. separation of their chiral components, is usually performed via asymmetric interaction with a chiral entity. In this paper we provide an experimental evidence of the chiral resolution of linearly polarized and unpolarized Gaussian beams through the transfer of spin angular momentum to chiral microparticles. Due to the interplay between linear and angular momentum exchange, basic manipulation tasks, as trapping, spinning or orbiting of micro-objects, can be performed by light with zero helicity. The results might broaden the perspectives for development of miniaturized and cost-effective devices.

  6. Measurement of the angular resolution of the ARGO-YBJ detector

    CERN Document Server

    Di Sciascio, G

    2007-01-01

    The ARGO-YBJ experiment is a full coverage EAS-array installed at the YangBaJing Cosmic Ray Laboratory (4300 m a.s.l., Tibet, P.R. China). We present the results on the angular resolution measured with different methods with the full central carpet. The comparison of experimental results with MC simulations is discussed.

  7. The High Angular Resolution Multiplicity of Massive Stars

    Science.gov (United States)

    2009-02-01

    4.9 10161−5954 HU 1597 83.90 0.365 48.8 93.4 1989.02 0.253 303.7 2 Ling & Prieto (1990) (5b) ±0.65 ±0.003 ±0.8 ±1.0 ±0.35 ±0.006 ±1.4 11441−0448 RST...26 Inf. Circ., 164 Docobo, J. A., & Prieto , C. 1996, IAU Comm. 26 Inf. Circ., 130 Docobo, J. A., Tamazian, V. S., Balega, Y. Y., Blanco, J., Maximov, A...in ASP Conf. Ser. 387, Massive Star Formation: Observations Confront Theory, ed. H. Beuther, H. Linz, & T. Henning (San Francisco , CA: ASP) 93 Gies

  8. The Prospects and Promise of High Angular Resolution Binary Orbits

    Science.gov (United States)

    Hartkopf, W. I.

    1999-12-01

    Just how many stellar masses are actually known to 1% or 5% or even 10% accuracy? How well do they really define the Mass-Luminosity relation? Is anything known about the M-L relation for post-Main Sequence stars? What progress is being made in improving the situation? How much of an impact did Hipparcos make? What about the new interferometers? This talk will focus on the advances which are finally being made in the determination of stellar masses. I believe we are about to enter a "golden age" for stellar evolution studies, when masses can be determined to sufficient accuracy and in sufficient numbers to define the M-L relation for different luminosity classes and perhaps even discern the subtle effects of metallicity and age. I'll discuss the new observing tools (now at hand or about to come on line) which will be responsible for bringing about these advances in our knowledge of this basic, but all-important stellar property.

  9. Angular observables for spin discrimination in boosted diboson final states

    CERN Document Server

    Buschmann, Malte

    2016-01-01

    We investigate the prospects for spin determination of a heavy diboson resonance using angular observables. Focusing in particular on boosted fully hadronic final states, we detail both the differences in signal efficiencies and distortions of differential distributions resulting from various jet substructure techniques. We treat the 2 TeV diboson excess as a case study, but our results are generally applicable to any future discovery in the diboson channel. Scrutinizing ATLAS and CMS analyses at 8 TeV and 13 TeV, we find that the specific cuts employed in these analyses have a tremendous impact on the discrimination power between different signal hypotheses. We discuss modified cuts that can offer a significant boost to spin sensitivity in a post-discovery era. Even without altered cuts, we show that CMS, and partly also ATLAS, will be able to distinguish between spin 0, 1, or 2 new physics diboson resonances at the $2\\sigma$ level with 30 fb$^{-1}$ of 13 TeV data, for our 2 TeV case study.

  10. Angular observables for spin discrimination in boosted diboson final states

    Science.gov (United States)

    Buschmann, Malte; Yu, Felix

    2016-09-01

    We investigate the prospects for spin determination of a heavy diboson resonance using angular observables. Focusing in particular on boosted fully hadronic final states, we detail both the differences in signal efficiencies and distortions of differential distributions resulting from various jet substructure techniques. We treat the 2 TeV diboson excess as a case study, but our results are generally applicable to any future discovery in the diboson channel. Scrutinizing ATLAS and CMS analyses at 8 TeV and 13 TeV, we find that the specific cuts employed in these analyses have a tremendous impact on the discrimination power between different signal hypotheses. We discuss modified cuts that can offer a significant boost to spin sensitivity in a post-discovery era. Even without altered cuts, we show that CMS, and partly also ATLAS, will be able to distinguish between spin 0, 1, or 2 new physics diboson resonances at the 2 σ level with 30 fb-1 of 13 TeV data, for our 2 TeV case study.

  11. European Extremely Large Telescope Site Characterization II: High angular resolution parameters

    CERN Document Server

    Ramió, Héctor Vázquez; Muñoz-Tuñón, Casiana; Sarazin, Marc; Varela, Antonia M; Trinquet, Hervé; Delgado, José Miguel; Fuensalida, Jesús J; Reyes, Marcos; Benhida, Abdelmajid; Benkhaldoun, Zouhair; Lambas, Diego García; Hach, Youssef; Lazrek, M; Lombardi, Gianluca; Navarrete, Julio; Recabarren, Pablo; Renzi, Victor; Sabil, Mohammed; Vrech, Rubén

    2012-01-01

    This is the second article of a series devoted to European Extremely Large Telescope (E-ELT) site characterization. In this article we present the main properties of the parameters involved in high angular resolution observations from the data collected in the site testing campaign of the E-ELT during the Design Study (DS) phase. Observations were made in 2008 and 2009, in the four sites selected to shelter the future E-ELT (characterized under the ELT-DS contract): Aklim mountain in Morocco, Observatorio del Roque de los Muchachos (ORM) in Spain, Mac\\'on range in Argentina, and Cerro Ventarrones in Chile. The same techniques, instruments and acquisition procedures were taken on each site. A Multiple Aperture Scintillation Sensor (MASS) and a Differential Image Motion Monitor (DIMM) were installed at each site. Global statistics of the integrated seeing, the free atmosphere seeing, the boundary layer seeing and the isoplanatic angle were studied for each site, and the results are presented here. In order to e...

  12. European Extremely Large Telescope Site Characterization. II. High Angular Resolution Parameters

    Science.gov (United States)

    Vázquez Ramió, Héctor; Vernin, Jean; Muñoz-Tuñón, Casiana; Sarazin, Marc; Varela, Antonia M.; Trinquet, Hervé; Delgado, José Miguel; Fuensalida, Jesús J.; Reyes, Marcos; Benhida, Abdelmajid; Benkhaldoun, Zouhair; García Lambas, Diego; Hach, Youssef; Lazrek, M.; Lombardi, Gianluca; Navarrete, Julio; Recabarren, Pablo; Renzi, Victor; Sabil, Mohammed; Vrech, Rubén

    2012-08-01

    This is the second article of a series devoted to European Extremely Large Telescope (E-ELT) site characterization. In this article we present the main properties of the parameters involved in high angular resolution observations from the data collected in the site testing campaign of the E-ELT during the design study (DS) phase. Observations were made in 2008 and 2009, in the four sites selected to shelter the future E-ELT (characterized under the ELT-DS contract): Aklim mountain in Morocco, Observatorio del Roque de los Muchachos (ORM) in Spain, Macón range in Argentina, and Cerro Ventarrones in Chile. The same techniques, instruments, and acquisition procedures were taken on each site. A multiple aperture scintillation sensor (MASS) and a differential image motion monitor (DIMM) were installed at each site. Global statistics of the integrated seeing, the free atmosphere seeing, the boundary layer seeing, and the isoplanatic angle were studied for each site, and the results are presented here. In order to estimate other important parameters, such as the coherence time of the wavefront and the overall parameter “coherence étendue,” additional information of vertical profiles of the wind speed was needed. Data were retrieved from the National Oceanic and Atmospheric Administration (NOAA) archive. Ground wind speed was measured by automatic weather stations (AWS). More aspects of the turbulence parameters, such as their seasonal trend, their nightly evolution, and their temporal stability, were also obtained and analyzed.

  13. Development of a high angular resolution diffusion imaging human brain template.

    Science.gov (United States)

    Varentsova, Anna; Zhang, Shengwei; Arfanakis, Konstantinos

    2014-05-01

    Brain diffusion templates contain rich information about the microstructure of the brain, and are used as references in spatial normalization or in the development of brain atlases. The accuracy of diffusion templates constructed based on the diffusion tensor (DT) model is limited in regions with complex neuronal micro-architecture. High angular resolution diffusion imaging (HARDI) overcomes limitations of the DT model and is capable of resolving intravoxel heterogeneity. However, when HARDI is combined with multiple-shot sequences to minimize image artifacts, the scan time becomes inappropriate for human brain imaging. In this work, an artifact-free HARDI template of the human brain was developed from low angular resolution multiple-shot diffusion data. The resulting HARDI template was produced in ICBM-152 space based on Turboprop diffusion data, was shown to resolve complex neuronal micro-architecture in regions with intravoxel heterogeneity, and contained fiber orientation information consistent with known human brain anatomy.

  14. Formation and evolution of planetary systems: the impact of high angular resolution optical techniques

    CERN Document Server

    Absil, Olivier; 10.1007/s00159-009-0028-y

    2009-01-01

    The direct images of giant extrasolar planets recently obtained around several main sequence stars represent a major step in the study of planetary systems. These high-dynamic range images are among the most striking results obtained by the current generation of high angular resolution instruments, which will be superseded by a new generation of instruments in the coming years. It is therefore an appropriate time to review the contributions of high angular resolution visible/infrared techniques to the rapidly growing field of extrasolar planetary science. During the last 20 years, the advent of the Hubble Space Telescope, of adaptive optics on 4- to 10-m class ground-based telescopes, and of long-baseline infrared stellar interferometry has opened a new viewpoint on the formation and evolution of planetary systems. By spatially resolving the optically thick circumstellar discs of gas and dust where planets are forming, these instruments have considerably improved our models of early circumstellar environments...

  15. Next Generation X-ray Optics: High Angular Resolution, Light Weight, and Low Production Cost

    Science.gov (United States)

    Zhang, William

    2014-08-01

    Every conceivable future x-ray astronomical mission would require x-ray optics. These optics must meet the three-fold requirements of angular resolution, effective area, and cost.In this poster we will present the rationale, technical approach, and status of an x-ray optics technology development program that has been underway at Goddard Space Flight Center and Marshall Space Flight Center.

  16. Sub-Airy disk angular resolution with high dynamic range in the near-infrared

    Directory of Open Access Journals (Sweden)

    Richichi A.

    2011-07-01

    Full Text Available Lunar occultations (LO are a simple and effective high angular resolution method, with minimum requirements in instrumentation and telescope time. They rely on the analysis of the diffraction fringes created by the lunar limb. The diffraction phenomen occurs in space, and as a result LO are highly insensitive to most of the degrading effects that limit the performance of traditional single telescope and long-baseline interferometric techniques used for direct detection of faint, close companions to bright stars. We present very recent results obtained with the technique of lunar occultations in the near-IR, showing the detection of companions with very high dynamic range as close as few milliarcseconds to the primary star. We discuss the potential improvements that could be made, to increase further the current performance. Of course, LO are fixed-time events applicable only to sources which happen to lie on the Moon’s apparent orbit. However, with the continuously increasing numbers of potential exoplanets and brown dwarfs beign discovered, the frequency of such events is not negligible. I will list some of the most favorable potential LO in the near future, to be observed from major observatories.

  17. A broadband x-ray imaging spectroscopy with high-angular resolution: the FORCE mission

    Science.gov (United States)

    Mori, Koji; Tsuru, Takeshi Go; Nakazawa, Kazuhiro; Ueda, Yoshihiro; Okajima, Takashi; Murakami, Hiroshi; Awaki, Hisamitsu; Matsumoto, Hironori; Fukazawa, Yasushi; Tsunemi, Hiroshi; Takahashi, Tadayuki; Zhang, William W.

    2016-07-01

    We are proposing FORCE (Focusing On Relativistic universe and Cosmic Evolution) as a future Japan-lead Xray observatory to be launched in the mid 2020s. Hitomi (ASTRO-H) possesses a suite of sensitive instruments enabling the highest energy-resolution spectroscopy in soft X-ray band, a broadband X-ray imaging spectroscopy in soft and hard X-ray bands, and further high energy coverage up to soft gamma-ray band. FORCE is the direct successor to the broadband X-ray imaging spectroscopy aspect of Hitomi (ASTRO-H) with significantly higher angular resolution. The current design of FORCE defines energy band pass of 1-80 keV with angular resolution of black holes" in various mass-scales: "buried supermassive black holes (SMBHs)" (> 104 M⊙) residing in the center of galaxies in a cosmological distance, "intermediate-mass black holes" (102-104 M⊙) acting as the possible seeds from which SMBHs grow, and "orphan stellar-mass black holes" (mirror and wide-band X-ray detector. The focal length is currently planned to be 10 m. The silicon mirror with multi-layer coating is our primary choice to achieve lightweight, good angular optics. The detector is a descendant of hard X-ray imager onboard Hitomi (ASTRO-H) replacing its silicon strip detector with SOI-CMOS silicon pixel detector, allowing an extension of the low energy threshold down to 1 keV or even less.

  18. Method for improving the angular resolution of a neutron scatter camera

    Science.gov (United States)

    Mascarenhas, Nicholas; Marleau, Peter; Gerling, Mark; Cooper, Robert Lee; Mrowka, Stanley; Brennan, James S.

    2012-12-25

    An instrument that will directly image the fast fission neutrons from a special nuclear material source wherein the neutron detection efficiency is increased has been described. Instead of the previous technique that uses a time-of-flight (TOF) between 2 widely spaced fixed planes of neutron detectors to measure scatter neutron kinetic energy, we now use the recoil proton energy deposited in the second of the 2 scatter planes which can now be repositioned either much closer together or further apart. However, by doubling the separation distance between the 2 planes from 20 cm to a distance of 40 cm we improved the angular resolution of the detector from about 12.degree. to about 10.degree.. A further doubling of the separation distance to 80 cm provided an addition improvement in angular resolution of the detector to about 6.degree. without adding additional detectors or ancillary electronics. The distance between planes also may be dynamically changed using a suitable common technique such as a gear- or motor-drive to toggle between the various positions. The angular resolution of this new configuration, therefore, is increased at the expanse of detection sensitivity. However, the diminished sensitivity may be acceptable for those applications where the detector is able to interrogate a particular site for an extended period.

  19. Frequency and Angular Resolution for Measuring, Presenting and Predicting Loudspeaker Polar Data

    DEFF Research Database (Denmark)

    Staffeldt, Henrik; Seidel, Felicity

    1996-01-01

    The spherical polar loudspeaker data available today are usually measured with such a coarse resolution that only rough estimates of the performance of sound systems can be predicted by applying these data. Complex, spherical polar data with higher angular and frequency resolutions than used today...... measurement principles and systems, in terms of specific levels of accuracy, are also discussed. The presented material consists of research the authors have done for the AES Standards Committee SC-04-03, working group on loudspeaker modeling and measurement, toward a goal set by that working group...

  20. Molecular outflows and hot molecular core in G24.78+0.08 at sub-arcsecond angular resolution

    OpenAIRE

    Beltran, M. T.; Cesaroni, R.; Zhang, Q; Galvan-Madrid, R.; Beuther, H.; Fallscheer, C.; Neri, R.; Codella, C.

    2011-01-01

    Context. This study is part of a large project to study the physics of accretion and molecular outflows towards a selected sample of high-mass star-forming regions that show evidence of infall and rotation from previous studies. Aims. We wish to make a thorough study at high-angular resolution of the structure and kinematics of the HMCs and corresponding molecular outflows in the high-mass star-forming region G24.78+0.08. Methods. We carried out SMA and IRAM PdBI observations at 1.3 and 1.4 m...

  1. A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors

    Science.gov (United States)

    2014-02-01

    Printed in the U.S.A. A HIGH ANGULAR RESOLUTION SURVEY OF MASSIVE STARS IN CYGNUS OB2: RESULTS FROM THE HUBBLE SPACE TELESCOPE FINE GUIDANCE SENSORS...angular resolution survey of massive OB stars in the Cygnus OB2 association that we conducted with the fine guidance sensor 1R (FGS1r) on the Hubble Space...al. 2009) and imaging observations (Maı́z Apellániz 2010). The fine guidance sensors (FGSs) aboard the Hubble Space Telescope (HST) provide us with

  2. High-angular resolution observations of the Pistol Star

    CERN Document Server

    Martayan, Christophe; Bouquin, Jean-Baptiste Le; Merand, Antoine; Montagnier, Guillaume; Selman, Fernando; Girard, Julien; Fox, Andrew; Baade, Dietrich; Fremat, Yves; Lobel, Alex; Martins, Fabrice; Patru, Fabien; Rivinius, Thomas; Sana, Hugues; Stefl, Stan; Zorec, Jean; Semaan, Thierry

    2010-01-01

    First results of near-IR adaptive optics (AO)-assisted imaging, interferometry, and spectroscopy of this Luminous Blue Variable (LBV) are presented. They suggest that the Pistol Star is at least double. If the association is physical, it would reinforce questions concerning the importance of multiplicity for the formation and evolution of extremely massive stars.

  3. Noise reduction methods in analysis of near infrared lunar occultation light curves for high angular resolution measurements

    CERN Document Server

    Baug, Tapas

    2013-01-01

    Lunar occultation (LO) technique in the near-infrared provides angular resolution down to milliarcseconds on the occulted source even with ground-based 1m class telescopes. LO observations are limited to brighter objects because they require high signal to noise ratio (S/N ~ 40) for proper extraction of angular diameter values. Hence, methods to improve the S/N ratio by reducing noise using Fourier and Wavelet transforms have been explored in this study. A sample of 54 near-infrared LO light curves observed with IR Camera at Mt Abu observatory has been used. It is seen that both Fourier and Wavelet methods have shown improvement in S/N, compared to the original data. However, the application of wavelet transforms results in slight smoothening of the fringes resulting in a higher angular diameter value. Fourier transforms which reduce discrete noise frequencies do not distort the fringe. Fourier transform method seems to be effective in S/N improvement, as well as improved model fit particularly in the fainter...

  4. Astronomy at high angular resolution a compendium of techniques in the visible and near-infrared

    CERN Document Server

    Hussain, Gaitee; Berger, Jean-Philippe; Schmidtobreick, Linda

    2016-01-01

    This book offers an essential compendium of astronomical high-resolution techniques. Recent years have seen considerable developments in such techniques, which are critical to advances in many areas of astronomy. As reflected in the book, these techniques can be divided into direct methods, interferometry, and reconstruction methods, and can be applied to a huge variety of astrophysical systems, ranging from planets, single stars and binaries to active galactic nuclei, providing angular resolution in the micro- to tens of milliarcsecond scales. Written by experts in their fields, the chapters cover adaptive optics, aperture masking imaging, spectra disentangling, interferometry, lucky imaging, Roche tomography, imaging with interferometry, interferometry of AGN, AGN reverberation mapping, Doppler- and magnetic imaging of stellar surfaces, Doppler tomography, eclipse mapping, Stokes imaging, and stellar tomography. This book is intended to enable a next generation of astronomers to apply high-resolution techni...

  5. Observation of Four-Photon Orbital Angular Momentum Entanglement

    Science.gov (United States)

    Hiesmayr, B. C.; de Dood, M. J. A.; Löffler, W.

    2016-02-01

    We demonstrate genuine multipartite quantum entanglement of four photons in their orbital angular momentum degrees of freedom, where a high-dimensional discrete Hilbert space is attached to each photon. This can encode more quantum information compared to the qubit case, but it is a long-standing problem to entangle more than two such photons. In our experiment we use pulsed spontaneous parametric down-conversion to produce the photon quadruplets, which allows us to detect about one four-photon event per second. By means of quantum state reconstruction and a suitable witness operator we find that the photon quadruplets form a genuine multipartite entangled symmetric Dicke state. This opens a new tool for addressing foundational questions in quantum mechanics, and for exploration of novel high-dimensional multiparty quantum information applications such as secret sharing.

  6. PREFACE: The Universe under the Microscope: Astrophysics at High Angular Resolution

    Science.gov (United States)

    Schödel, Rainer

    2009-01-01

    High angular resolution techniques at infrared and centimeter to millimeter wavelengths have become of ever increasing importance for astrophysical research in the past decade. They have led to important breakthroughs, like the direct imaging of protoplanetary discs and of the first exoplanets, the measurement of stellar orbits around the black hole at the center of the Milky Way, or the detection of sub-parsec-scale jets in low luminosity AGN. With adaptive optics in a mature state, infrared/optical astronomy is pushing toward extreme adaptive optics, extremely large telescopes, and infrared/optical interferometry with large aperture telescopes. At longer wavelengths, large arrays start to conquer the sub-millimeter window, with the mid-term goal of global VLBI at sub-millimeter wavelengths. These new techniques will have enormous impact on the field because they will enable us to address issues such as directly measuring the properties of exoplanets, imaging the surfaces of stars, examining stellar dynamics in extremely dense cluster cores, disentangling the processes at the bottom of black hole accretion flows in the jet launching region, or testing general relativity in the strong gravity regime near the event horizon of supermassive black holes. The conference The Universe under the Microscope: Astrophysics at High Angular Resolution, held at the Physikzentrum of the Deutsche Physikalische Gesellschaft in Bad Honnef, Germany, on 12-25 April 2008, aimed at an interdisciplinary approach by bringing together astrophysicists from the three great branches of the field, instrumentation, observation, and theory, to discuss the current state of research and the possibilities offered by the next-generation instruments. Editors of the proceedings Rainer Schödel Instituto de Astrofísica de Andalucía -CSIC, Granada, Spain Andreas Eckart I. Physikalisches Institut der Universität zu Köln, Köln, Germany Susanne Pfalzner I. Physikalisches Institut der Universität zu

  7. Multi‐angular observations of vegetation indices from UAV cameras

    DEFF Research Database (Denmark)

    Sobejano-Paz, Veronica; Wang, Sheng; Jakobsen, Jakob

    Unmanned aerial vehicles (UAVs) are found as an alternative to the classical manned aerial photogrammetry, which can be used to obtain environmental data or as a complementary solution to other methods (Nex and Remondino, 2014). Although UAVs have coverage limitations, they have better resolution...

  8. X-ray interferometry with transmissive beam combiners for ultra-high angular resolution astronomy

    CERN Document Server

    Skinner, G K; 10.1007/s10686-009-9175-4

    2009-01-01

    Interferometry provides one of the possible routes to ultra-high angular resolution for X-ray and gamma-ray astronomy. Sub-micro-arc-second angular resolution, necessary to achieve objectives such as imaging the regions around the event horizon of a super-massive black hole at the center of an active galaxy, can be achieved if beams from parts of the incoming wavefront separated by 100s of meters can be stably and accurately brought together at small angles. One way of achieving this is by using grazing incidence mirrors. We here investigate an alternative approach in which the beams are recombined by optical elements working in transmission. It is shown that the use of diffractive elements is a particularly attractive option. We report experimental results from a simple 2-beam interferometer using a low-cost commercially available profiled film as the diffractive elements. A rotationally symmetric filled (or mostly filled) aperture variant of such an interferometer, equivalent to an X-ray axicon, is shown to...

  9. Geometrically necessary dislocation densities in olivine obtained using high-angular resolution electron backscatter diffraction.

    Science.gov (United States)

    Wallis, David; Hansen, Lars N; Ben Britton, T; Wilkinson, Angus J

    2016-09-01

    Dislocations in geological minerals are fundamental to the creep processes that control large-scale geodynamic phenomena. However, techniques to quantify their densities, distributions, and types over critical subgrain to polycrystal length scales are limited. The recent advent of high-angular resolution electron backscatter diffraction (HR-EBSD), based on diffraction pattern cross-correlation, offers a powerful new approach that has been utilised to analyse dislocation densities in the materials sciences. In particular, HR-EBSD yields significantly better angular resolution (olivine, the dominant mineral in Earth's upper mantle by testing (1) different inversion methods for estimating geometrically necessary dislocation (GND) densities, (2) the sensitivity of the method under a range of data acquisition settings, and (3) the ability of the technique to resolve a variety of olivine dislocation structures. The relatively low crystal symmetry (orthorhombic) and few slip systems in olivine result in well constrained GND density estimates. The GND density noise floor is inversely proportional to map step size, such that datasets can be optimised for analysing either short wavelength, high density structures (e.g. subgrain boundaries) or long wavelength, low amplitude orientation gradients. Comparison to conventional images of decorated dislocations demonstrates that HR-EBSD can characterise the dislocation distribution and reveal additional structure not captured by the decoration technique. HR-EBSD therefore provides a highly effective method for analysing dislocations in olivine and determining their role in accommodating macroscopic deformation.

  10. X-ray Interferometry with Transmissive Beam Combiners for Ultra-High Angular Resolution Astronomy

    Science.gov (United States)

    Skinner, G. K.; Krismanic, John F.

    2009-01-01

    Abstract Interferometry provides one of the possible routes to ultra-high angular resolution for X-ray and gamma-ray astronomy. Sub-micro-arc-second angular resolution, necessary to achieve objectives such as imaging the regions around the event horizon of a super-massive black hole at the center of an active galaxy, can be achieved if beams from parts of the incoming wavefront separated by 100s of meters can be stably and accurately brought together at small angles. One way of achieving this is by using grazing incidence mirrors. We here investigate an alternative approach in which the beams are recombined by optical elements working in transmission. It is shown that the use of diffractive elements is a particularly attractive option. We report experimental results from a simple 2-beam interferometer using a low-cost commercially available profiled film as the diffractive elements. A rotationally symmetric filled (or mostly filled) aperture variant of such an interferometer, equivalent to an X-ray axicon, is shown to offer a much wider bandpass than either a Phase Fresnel Lens (PFL) or a PFL with a refractive lens in an achromatic pair. Simulations of an example system are presented.

  11. Contrast and resolution analysis of angular domain imaging for iterative optical projection tomography reconstruction

    Science.gov (United States)

    Ng, Eldon; Vasefi, Fartash; Kaminska, Bozena; Chapman, Glenn H.; Carson, Jeffrey J. L.

    2010-02-01

    Angular domain imaging (ADI) generates a projection image of an attenuating target within a turbid medium by employing a silicon micro-tunnel array to reject photons that have deviated from the initial propagation direction. In this imaging method, image contrast and resolution are position dependent. The objective of this work was to first characterize the contrast and resolution of the ADI system at a multitude of locations within the imaging plane. The second objective was to compare the reconstructions of different targets using filtered back projection and iterative reconstruction algorithms. The ADI system consisted of a diode laser laser (808nm, CW, ThorLabs) with a beam expander for illumination of the sample cuvette. At the opposite side of the cuvette, an Angular Filter Array (AFA) of 80 μm x 80 μm square-shaped tunnels 1 cm in length was used to reject the transmitted scattered light. Image-forming light exiting the AFA was detected by a linear CCD (16-bit, Mightex). Our approach was to translate two point attenuators (0.5 mm graphite rod, 0.368 mm drill bit) submerged in a 0.6% IntralipidTM dilution using a SCARA robot (Epson E2S351S) to cover a 37x37 and 45x45 matrix of grid points in the imaging plane within the 1 cm path length sample cuvette. At each grid point, a one-dimensional point-spread distribution was collected and system contrast and resolution were measured. Then, the robot was used to rotate the target to collect projection images at several projection angles of various objects, and reconstructed with a filtered back projection and an iterative reconstruction algorithm.

  12. Converting Multi-Shell and Diffusion Spectrum Imaging to High Angular Resolution Diffusion Imaging.

    Science.gov (United States)

    Yeh, Fang-Cheng; Verstynen, Timothy D

    2016-01-01

    Multi-shell and diffusion spectrum imaging (DSI) are becoming increasingly popular methods of acquiring diffusion MRI data in a research context. However, single-shell acquisitions, such as diffusion tensor imaging (DTI) and high angular resolution diffusion imaging (HARDI), still remain the most common acquisition schemes in practice. Here we tested whether multi-shell and DSI data have conversion flexibility to be interpolated into corresponding HARDI data. We acquired multi-shell and DSI data on both a phantom and in vivo human tissue and converted them to HARDI. The correlation and difference between their diffusion signals, anisotropy values, diffusivity measurements, fiber orientations, connectivity matrices, and network measures were examined. Our analysis result showed that the diffusion signals, anisotropy, diffusivity, and connectivity matrix of the HARDI converted from multi-shell and DSI were highly correlated with those of the HARDI acquired on the MR scanner, with correlation coefficients around 0.8~0.9. The average angular error between converted and original HARDI was 20.7° at voxels with signal-to-noise ratios greater than 5. The network topology measures had less than 2% difference, whereas the average nodal measures had a percentage difference around 4~7%. In general, multi-shell and DSI acquisitions can be converted to their corresponding single-shell HARDI with high fidelity. This supports multi-shell and DSI acquisitions over HARDI acquisition as the scheme of choice for diffusion acquisitions.

  13. High resolution gamma-ray spectroscopy and the fascinating angular momentum realm of the atomic nucleus

    Science.gov (United States)

    Riley, M. A.; Simpson, J.; Paul, E. S.

    2016-12-01

    In 1974 Aage Bohr and Ben Mottelson predicted the different ‘phases’ that may be expected in deformed nuclei as a function of increasing angular momentum and excitation energy all the way up to the fission limit. While admitting their picture was highly conjectural they confidently stated ‘...with the ingenious experimental approaches that are being developed, we may look forward with excitement to the detailed spectroscopic studies that will illuminate the behaviour of the spinning quantised nucleus’. High resolution gamma-ray spectroscopy has indeed been a major tool in studying the structure of atomic nuclei and has witnessed numerous significant advances over the last four decades. This article will select highlights from investigations at the Niels Bohr Institute, Denmark, and Daresbury Laboratory, UK, in the late 1970s and early 1980s, some of which have continued at other national laboratories in Europe and the USA to the present day. These studies illustrate the remarkable diversity of phenomena and symmetries exhibited by nuclei in the angular momentum-excitation energy plane that continue to surprise and fascinate scientists.

  14. Converting Multi-Shell and Diffusion Spectrum Imaging to High Angular Resolution Diffusion Imaging

    Science.gov (United States)

    Yeh, Fang-Cheng; Verstynen, Timothy D.

    2016-01-01

    Multi-shell and diffusion spectrum imaging (DSI) are becoming increasingly popular methods of acquiring diffusion MRI data in a research context. However, single-shell acquisitions, such as diffusion tensor imaging (DTI) and high angular resolution diffusion imaging (HARDI), still remain the most common acquisition schemes in practice. Here we tested whether multi-shell and DSI data have conversion flexibility to be interpolated into corresponding HARDI data. We acquired multi-shell and DSI data on both a phantom and in vivo human tissue and converted them to HARDI. The correlation and difference between their diffusion signals, anisotropy values, diffusivity measurements, fiber orientations, connectivity matrices, and network measures were examined. Our analysis result showed that the diffusion signals, anisotropy, diffusivity, and connectivity matrix of the HARDI converted from multi-shell and DSI were highly correlated with those of the HARDI acquired on the MR scanner, with correlation coefficients around 0.8~0.9. The average angular error between converted and original HARDI was 20.7° at voxels with signal-to-noise ratios greater than 5. The network topology measures had less than 2% difference, whereas the average nodal measures had a percentage difference around 4~7%. In general, multi-shell and DSI acquisitions can be converted to their corresponding single-shell HARDI with high fidelity. This supports multi-shell and DSI acquisitions over HARDI acquisition as the scheme of choice for diffusion acquisitions. PMID:27683539

  15. Improved angular resolution in electron backscatter diffraction analysis by use of image correlation techniques

    Institute of Scientific and Technical Information of China (English)

    CUI HY; Andrew GODFREY; WANG W

    2008-01-01

    In this paper we describe a method for improving the angular resolution of the electron backscatter diffraction(EBSD)technique based on a correlative matching of EBSD patterns.Standard image interpolation methods are used to detect shifts between selected regions of the EBSD patterns to an accuracy of one tenth of a pixel.Simulated data sets are used to show that such accuracy,combined with a small angle approximation in calculation of the rotation angle,allows determination of the misorientation between patterns to an accuracy of 0.01 degrees.The method is tested on samples of both single crystal aluminum and recrystallized nickel.The results demonstrate the accuracy and stability of the new method compared to the conventional method.

  16. Observation of Interaction of Spin and Intrinsic Orbital Angular Momentum of Light

    CERN Document Server

    Vitullo, Dashiell L P; Gregg, Patrick; Smith, Roger A; Reddy, Dileep V; Ramachandran, Siddharth; Raymer, Michael G

    2016-01-01

    Spin and intrinsic orbital angular momentum interaction of light is observed, as evidenced by length-dependent rotations of both spatial patterns and optical polarization in an isotropic optical fiber. The distinction between intrinsic and extrinsic orbital angular momentum (as seen in helically coiled fiber) is made clear by controllable excitation of a small number of optical modes in a straight, few-mode fiber.

  17. ONE-DIMENSIONAL LIGHT BEAM WIDENING USING PRISMS FOR INCREASE OF SPECTROMETER SPECTRAL RESOLUTION AND ANGULAR DISPERSION

    Directory of Open Access Journals (Sweden)

    I. M. Gulis

    2016-01-01

    Full Text Available The increase of angular dispersion and slit resolution limit of grating spectrometers by means of variation of grating parameters is limited by its period and allowable order of diffraction. The special solutions (echelle, holographic, immersion gratings are acceptable in a limited parameter range and are technologically complex in fabrication, thus hardly applicable to instruments of mass production. We propose to decrease slit resolution limit by one-dimensional beam widening in dispersion plane by means of passing it through oblique prism before incidence onto diffraction grating. The increase of angular dispersion can be achieved by narrowing of dispersed beams after grating while passing through other oblique prism. We prove that slit resolution limit in such a system changes approximately as multiplied by angular magnification of the first prism (that is less than 1 times. Also angular dispersion changed approximately as multiplied by angular magnification of the second prism. The Fresnel reflection from the faces of prisms is analyzed. Accounting for that factor gives the increase of resolution about 1,4–1,6 times without loss of light (and can be 2 and more times while using anti-reflective coating. The proposed method is different from the similar ones first of all by its simplicity because it uses simple optical elements – plane reflective grating and thin prisms. It can be applied to amend the analytical characteristics of dispersive spectrometers, first of all the small-sized ones. 

  18. High Angular Resolution Stellar Imaging with Occultations from the Cassini Spacecraft II: Kronocyclic Tomography

    CERN Document Server

    Stewart, Paul N; Nicholson, Philip D; Hedman, Matthew M; Lloyd, James P

    2015-01-01

    We present an advance in the use of Cassini observations of stellar occultations by the rings of Saturn for stellar studies. Stewart et al. (2013) demonstrated the potential use of such observations for measuring stellar angular diameters. Here, we use these same observations, and tomographic imaging reconstruction techniques, to produce two dimensional images of complex stellar systems. We detail the determination of the basic observational reference frame. A technique for recovering model-independent brightness profiles for data from each occulting edge is discussed, along with the tomographic combination of these profiles to build an image of the source star. Finally we demonstrate the technique with recovered images of the {\\alpha} Centauri binary system and the circumstellar environment of the evolved late-type giant star, Mira.

  19. The GAMMA-400 gamma-ray telescope characteristics. Angular resolution and electrons/protons separation

    CERN Document Server

    Leonov, A A; Bonvicini, V; Topchiev, N P; Adriani, O; Aptekar, R L; Arkhangelskaja, I V; Arkhangelskiy, A I; Bergstrom, L; Berti, E; Bigongiari, G; Bobkov, S G; Boezio, M; Bogomolov, E A; Bonechi, S; Bongi, M; Bottai, S; Boyarchuk, K A; Castellini, G; Cattaneo, P W; Cumani, P; Dedenko, G L; De Donato, C; Dogiel, V A; Gorbunov, M S; Gusakov, Yu V; Hnatyk, B I; Kadilin, V V; Kaplin, V A; Kaplun, A A; Kheymits, M D; Korepanov, V E; Larsson, J; Loginov, V A; Longo, F; Maestro, P; Marrocchesi, P S; Mikhailov, V V; Mocchiutti, E; Moiseev, A A; Mori, N; Moskalenko, I V; Naumov, P Yu; Papini, P; Pearce, M; Picozza, P; Popov, A V; Rappoldi, A; Ricciarini, S; Runtso, M F; Ryde, F; Serdin, O V; Sparvoli, R; Spillantini, P; Suchkov, S I; Tavani, M; Taraskin, A A; Tiberio, A; Tyurin, E M; Ulanov, M V; Vacchi, A; Vannuccini, E; Vasilyev, G I; Yurkin, Yu T; Zampa, N; Zirakashvili, V N; Zverev, V G

    2014-01-01

    The measurements of gamma-ray fluxes and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV, which will be implemented by the specially designed GAMMA-400 gamma-ray telescope, concern with the following broad range of science topics. Searching for signatures of dark matter, surveying the celestial sphere in order to study gamma-ray point and extended sources, measuring the energy spectra of Galactic and extragalactic diffuse gamma-ray emission, studying gamma-ray bursts and gamma-ray emission from the Sun, as well as high precision measuring spectra of high-energy electrons and positrons, protons and nuclei up to the knee. To clarify these scientific problems with the new experimental data the GAMMA-400 gamma-ray telescope possesses unique physical characteristics comparing with previous and present experiments. For gamma-ray energies more than 100 GeV GAMMA-400 provides the energy resolution of ~1% and angular resolution better than 0.02 deg. The methods developed to reconstru...

  20. The Multiplicity of Massive Stars: A High Angular Resolution Survey with the HST Fine Guidance Sensor

    CERN Document Server

    Aldoretta, E J; Gies, D R; Nelan, E P; Wallace, D J; Hartkopf, W I; Henry, T J; Jao, W -C; Apellániz, J Maíz; Mason, B D; Moffat, A F J; Norris, R P; Richardson, N D; Williams, S J

    2014-01-01

    We present the results of an all-sky survey made with the Fine Guidance Sensor on Hubble Space Telescope to search for angularly resolved binary systems among the 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 detection of companions with an angular separation between 0."01 and 1."0 and brighter than $\\triangle m = 5$. 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...

  1. Molecular outflows and hot molecular core in G24.78+0.08 at sub-arcsecond angular resolution

    CERN Document Server

    Beltran, M T; Zhang, Q; Galvan-Madrid, R; Beuther, H; Fallscheer, C; Neri, R; Codella, C

    2011-01-01

    Context. This study is part of a large project to study the physics of accretion and molecular outflows towards a selected sample of high-mass star-forming regions that show evidence of infall and rotation from previous studies. Aims. We wish to make a thorough study at high-angular resolution of the structure and kinematics of the HMCs and corresponding molecular outflows in the high-mass star-forming region G24.78+0.08. Methods. We carried out SMA and IRAM PdBI observations at 1.3 and 1.4 mm, respectively, of dust and of typical high-density and molecular outflow tracers with resolutions of <1". Complementary IRAM 30-m 12CO and 13CO observations were carried out to recover the short spacing information of the molecular outflows. Results. The millimeter continuum emission towards cores G24 A1 and A2 has been resolved into 3 and 2 cores, respectively, and named A1, A1b, A1c, A2, and A2b. All these cores are aligned in a southeast-northwest direction coincident with that of the molecular outflows detected i...

  2. Importance of energy and angular resolutions in top-hat electrostatic analysers for solar wind proton measurements

    Science.gov (United States)

    De Marco, R.; Marcucci, M. F.; Bruno, R.; D'Amicis, R.; Servidio, S.; Valentini, F.; Lavraud, B.; Louarn, P.; Salatti, M.

    2016-08-01

    We use a numerical code which reproduces the angular/energy response of a typical top-hat electrostatic analyser starting from solar wind proton velocity distribution functions (VDFs) generated by numerical simulations. The simulations are based on the Hybrid Vlasov-Maxwell numerical algorithm which integrates the Vlasov equation for the ion distribution function, while the electrons are treated as a fluid. A virtual satellite launched through the simulation box measures the particle VDFs. Such VDFs are moved from the simulation Cartesian grid to energy-angular coordinates to mimic the response of a real sensor in the solar wind. Different energy-angular resolutions of the analyser are investigated in order to understand the influence of the phase-space resolution in existing and upcoming space missions, with regards to determining the key parameters of plasma dynamics.

  3. γ-ray telescopes using conversions to e+e- pairs: event generators, angular resolution and polarimetry

    Science.gov (United States)

    Gros, P.; Bernard, D.

    2017-02-01

    We benchmark various available event generators in Geant4 and EGS5 in the light of ongoing projects for high angular-resolution pair-conversion telescopes at low energy. We compare the distributions of key kinematic variables extracted from the geometry of the three final state particles. We validate and use as reference an exact generator using the full 5D differential cross-section of the conversion process. We focus in particular on the effect of the unmeasured recoiling nucleus on the angular resolution. We show that for high resolution trackers, the choice of the generator affects the estimated resolution of the telescope. We also show that the current available generator are unable to describe accurately a linearly polarised photon source.

  4. Geometrically necessary dislocation densities in olivine obtained using high-angular resolution electron backscatter diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Wallis, David, E-mail: davidwa@earth.ox.ac.uk [Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, Oxfordshire, OX1 3AN (United Kingdom); Hansen, Lars N. [Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, Oxfordshire, OX1 3AN (United Kingdom); Ben Britton, T. [Department of Materials, Imperial College London, Royal School of Mines, Exhibition Road, London SW7 2AZ (United Kingdom); Wilkinson, Angus J. [Department of Materials, University of Oxford, Parks Road, Oxford, Oxfordshire, OX1 3PH (United Kingdom)

    2016-09-15

    Dislocations in geological minerals are fundamental to the creep processes that control large-scale geodynamic phenomena. However, techniques to quantify their densities, distributions, and types over critical subgrain to polycrystal length scales are limited. The recent advent of high-angular resolution electron backscatter diffraction (HR-EBSD), based on diffraction pattern cross-correlation, offers a powerful new approach that has been utilised to analyse dislocation densities in the materials sciences. In particular, HR-EBSD yields significantly better angular resolution (<0.01°) than conventional EBSD (~0.5°), allowing very low dislocation densities to be analysed. We develop the application of HR-EBSD to olivine, the dominant mineral in Earth's upper mantle by testing (1) different inversion methods for estimating geometrically necessary dislocation (GND) densities, (2) the sensitivity of the method under a range of data acquisition settings, and (3) the ability of the technique to resolve a variety of olivine dislocation structures. The relatively low crystal symmetry (orthorhombic) and few slip systems in olivine result in well constrained GND density estimates. The GND density noise floor is inversely proportional to map step size, such that datasets can be optimised for analysing either short wavelength, high density structures (e.g. subgrain boundaries) or long wavelength, low amplitude orientation gradients. Comparison to conventional images of decorated dislocations demonstrates that HR-EBSD can characterise the dislocation distribution and reveal additional structure not captured by the decoration technique. HR-EBSD therefore provides a highly effective method for analysing dislocations in olivine and determining their role in accommodating macroscopic deformation. - Highlights: • Lattice orientation gradients in olivine were measured using HR-EBSD. • The limited number of olivine slip systems enable simple least squares inversion for GND

  5. Stability of dislocation structures in copper towards stress relaxation investigated by high angular resolution 3D X-ray diffraction

    DEFF Research Database (Denmark)

    Jakobsen, Bo; Poulsen, Henning Friis; Lienert, Ulrich

    2009-01-01

    A 300 µm thick tensile specimen of OFHC copper is subjected to a tensile loading sequence and deformed to a maximal strain of 3.11%. Using the novel three-dimensional X-ray diffraction method High angular resolution 3DXRD', the evolution of the microstructure within a deeply embedded grain is cha...

  6. Segmentation of high angular resolution diffusion MRI using sparse riemannian manifold clustering.

    Science.gov (United States)

    Çetingül, H Ertan; Wright, Margaret J; Thompson, Paul M; Vidal, René

    2014-02-01

    We address the problem of segmenting high angular resolution diffusion imaging (HARDI) data into multiple regions (or fiber tracts) with distinct diffusion properties. We use the orientation distribution function (ODF) to model diffusion and cast the ODF segmentation problem as a clustering problem in the space of ODFs. Our approach integrates tools from sparse representation theory and Riemannian geometry into a graph theoretic segmentation framework. By exploiting the Riemannian properties of the space of ODFs, we learn a sparse representation for each ODF and infer the segmentation by applying spectral clustering to a similarity matrix built from these representations. In cases where regions with similar (resp. distinct) diffusion properties belong to different (resp. same) fiber tracts, we obtain the segmentation by incorporating spatial and user-specified pairwise relationships into the formulation. Experiments on synthetic data evaluate the sensitivity of our method to image noise and to the concentration parameters, and show its superior performance compared to alternative methods when analyzing complex fiber configurations. Experiments on phantom and real data demonstrate the accuracy of the proposed method in segmenting simulated fibers and white matter fiber tracts of clinical importance.

  7. Implementation of $ab$ $initio$ perturbed angular correlation observables for analysis of fluctuating quadrupole interactions

    CERN Document Server

    Barbosa, Marcelo

    A review about the nuclear properties, namely the nuclear moments (magnetic dipole moment and electric quadrupole moment) and their interaction with electromagnetic fields external to the nucleus (hyperfine interactions), as well as the angular distribution of radiation produced by $\\gamma$-decay, is presented. A detailed description about the theory of Perturbed Angular Correlations was done, including the comparison between $\\gamma-\\gamma$- correlations and $e^{-}- \\gamma$ correlations. For dynamic nuclear interactions, an introduction to the theory of stochastic states in PAC was performed. We focused on ab-initio implementation of observables for analyzing fluctuating quadrupole hyperfine interactions on time dependent perturbed angular correlations experiments. The development of computacional codes solving the full problem, adapted to fit data obtained on single crystals or polycrystals for two-state transient fields with any axial symmetry and orientation was the main purpose of this work. The final pa...

  8. A super-high angular resolution principle for coded-mask X-ray imaging beyond the diffraction limit of a single pinhole

    Institute of Scientific and Technical Information of China (English)

    Chen Zhang; Shuang-Nan Zhang

    2009-01-01

    High angular resolution X-ray imaging is always useful in astrophysics and solar physics. In principle, it can be performed by using coded-mask imaging with a very long mask-detector distance. Previously, the diffraction-interference effect was thought to degrade coded-mask imaging performance dramatically at the low energy end with its very long mask-detector distance. The diffraction-interference effect is described with numerical calculations, and the difffraction-interference cross correlation reconstruction method (DICC) is developed in order to overcome the imaging performance degradation. Based on the DICC, a super-high angular resolution principle (SHARP) for coded-mask X-ray imaging is proposed. The feasibility of coded mask imaging beyond the diffraction limit of a single pinhole is demonstrated with simulations. With the specification that the mask element size is 50 × 50 μm2 and the mask-detector distance is 50 m, the achieved angular resolution is 0.32arcsec above about 10keV and 0.36arcsec at 1.24keV (λ = 1 nm), where diffraction cannot be neglected. The on-axis source location accuracy is better than 0.02 arcsec. Potential applications for solar observations and wide-field X-ray monitors are also briefly discussed.

  9. Probing the Higgs with angular observables at future e+e- colliders

    Science.gov (United States)

    Liu, Zhen

    2016-10-01

    I summarize our recent works on using differential observables to explore the physics potential of future e+e- colliders in the framework of Higgs effective field theory. This proceeding is based upon Refs. 1 and 2. We study angular observables in the e+e-→ ZHℓ+ℓ-bb¯ channel at future circular e+e- colliders such as CEPC and FCC-ee. Taking into account the impact of realistic cut acceptance and detector effects, we forecast the precision of six angular asymmetries at CEPC (FCC-ee) with center-of-mass energy s = 240 GeV and 5 (30) ab-1 integrated luminosity. We then determine the projected sensitivity to a range of operators relevant for the Higgsstrahlung process in the dimension-6 Higgs EFT. Our results show that angular observables provide complementary sensitivity to rate measurements when constraining various tensor structures arising from new physics. We further find that angular asymmetries provide a novel means of constraining the “blind spot” in indirect limits on supersymmetric scalar top partners. We also discuss the possibility of using ZZ-fusion at e+e- machines at different energies to probe new operators.

  10. High-Resolution CH Observations of Two Translucent Molecular Clouds

    Science.gov (United States)

    Chastain, Raymond J.; Cotten, David; Magnani, Loris

    2010-01-01

    We present high-resolution (1farcm3 × 1farcm6) observations of the CH 2Π1/2 (F = 1-1) emission line at 3335 MHz in two high-latitude translucent clouds, MBM 3 and 40. At the assumed cloud distances, the angular resolution corresponds to ~0.05 pc, nearly an order of magnitude better than previous studies. Comparisons of the CH emission with previously obtained CO(1-0) data are difficult to interpret: the CO and CH line emission correlates in MBM 40 but not in MBM 3. In both clouds, there is a spatial offset in the peak emission, and perhaps in velocity for MBM 40. The difference in emission characteristics for the two tracers are noticeable in these two nearby clouds because of the high spatial resolution. Since both CH and CO are deemed to be reliable tracers of H2, our results indicate that more care should be taken when using one of these tracers to determine the mass of a nearby molecular cloud.

  11. Experiment Design and First Season Observations with the Degree Angular Scale Interferometer

    OpenAIRE

    Leitch, E.M.; Pryke, C; Halverson, N. W.; Kovac, J.; Davidson, G.; LaRoque, S.; Schartman, E.; Yamasaki, J; Carlstrom, J. E.; Holzapfel, W. L.; Dragovan, M.; Cartwright, J. K.; Mason, B S; Padin, S.; Pearson, T. J.

    2001-01-01

    We describe the instrumentation, experiment design and data reduction for the first season of observations with the Degree Angular Scale Interferometer (DASI), a compact microwave interferometer designed to measure anisotropy in the Cosmic Microwave Background (CMB) on degree and sub-degree scales (l=100--900). The telescope was deployed at the Amundsen-Scott South Pole research station during the 1999--2000 austral summer and conducted observations of the CMB throughout the following austral...

  12. The photon angular momentum controversy: Resolution of a conflict between laser optics and particle physics

    Science.gov (United States)

    Leader, Elliot

    2016-05-01

    The claim some years ago, contrary to all textbooks, that the angular momentum of a photon (and gluon) can be split in a gauge-invariant way into an orbital and spin term, sparked a major controversy in the Particle Physics community, exacerbated by the realization that many different forms of the angular momentum operators are, in principle, possible. A further cause of upset was the realization that the gluon polarization in a nucleon, a supposedly physically meaningful quantity, corresponds only to the gauge-variant gluon spin derived from Noether's theorem, evaluated in a particular gauge. On the contrary, Laser Physicists have, for decades, been happily measuring physical quantities which correspond to photon orbital and spin angular momentum evaluated in a particular gauge. This paper reconciles the two points of view, and shows that it is the gauge invariant version of the canonical angular momentum which agrees with the results of a host of laser optics experiments.

  13. The photon angular momentum controversy: Resolution of a conflict between laser optics and particle physics

    Energy Technology Data Exchange (ETDEWEB)

    Leader, Elliot, E-mail: e.leader@imperial.ac.uk

    2016-05-10

    The claim some years ago, contrary to all textbooks, that the angular momentum of a photon (and gluon) can be split in a gauge-invariant way into an orbital and spin term, sparked a major controversy in the Particle Physics community, exacerbated by the realization that many different forms of the angular momentum operators are, in principle, possible. A further cause of upset was the realization that the gluon polarization in a nucleon, a supposedly physically meaningful quantity, corresponds only to the gauge-variant gluon spin derived from Noether's theorem, evaluated in a particular gauge. On the contrary, Laser Physicists have, for decades, been happily measuring physical quantities which correspond to photon orbital and spin angular momentum evaluated in a particular gauge. This paper reconciles the two points of view, and shows that it is the gauge invariant version of the canonical angular momentum which agrees with the results of a host of laser optics experiments.

  14. The photon angular momentum controversy: Resolution of a conflict between laser optics and particle physics

    Directory of Open Access Journals (Sweden)

    Elliot Leader

    2016-05-01

    Full Text Available The claim some years ago, contrary to all textbooks, that the angular momentum of a photon (and gluon can be split in a gauge-invariant way into an orbital and spin term, sparked a major controversy in the Particle Physics community, exacerbated by the realization that many different forms of the angular momentum operators are, in principle, possible. A further cause of upset was the realization that the gluon polarization in a nucleon, a supposedly physically meaningful quantity, corresponds only to the gauge-variant gluon spin derived from Noether's theorem, evaluated in a particular gauge. On the contrary, Laser Physicists have, for decades, been happily measuring physical quantities which correspond to photon orbital and spin angular momentum evaluated in a particular gauge. This paper reconciles the two points of view, and shows that it is the gauge invariant version of the canonical angular momentum which agrees with the results of a host of laser optics experiments.

  15. Experiment Design and First Season Observations with the Degree Angular Scale Interferometer

    CERN Document Server

    Leitch, E M; Halverson, N W; Kovács, J; Davidson, G; LaRoque, S J; Schartman, E; Yamasaki, J; Carlstrom, J E; Holzapfel, W L; Dragovan, M; Cartwright, J K; Mason, B S; Padin, S; Pearson, T J; Shepherd, M C; Readhead, A C S

    2002-01-01

    We describe the instrumentation, experiment design and data reduction for the first season of observations with the Degree Angular Scale Interferometer (DASI), a compact microwave interferometer designed to measure anisotropy in the Cosmic Microwave Background (CMB) on degree and sub-degree scales (l=100--900). The telescope was deployed at the Amundsen-Scott South Pole research station during the 1999--2000 austral summer and conducted observations of the CMB throughout the following austral winter. In its first season of observations, DASI has mapped CMB fluctuations in 32 fields, each 3.4 deg across, with high sensitivity.

  16. Spacecraft Angular Rates Estimation with Gyrowheel Based on Extended High Gain Observer

    Directory of Open Access Journals (Sweden)

    Xiaokun Liu

    2016-04-01

    Full Text Available A gyrowheel (GW is a kind of electronic electric-mechanical servo system, which can be applied to a spacecraft attitude control system (ACS as both an actuator and a sensor simultaneously. In order to solve the problem of two-dimensional spacecraft angular rate sensing as a GW outputting three-dimensional control torque, this paper proposed a method of an extended high gain observer (EHGO with the derived GW mathematical model to implement the spacecraft angular rate estimation when the GW rotor is working at large angles. For this purpose, the GW dynamic equation is firstly derived with the second kind Lagrange method, and the relationship between the measurable and unmeasurable variables is built. Then, the EHGO is designed to estimate and calculate spacecraft angular rates with the GW, and the stability of the designed EHGO is proven by the Lyapunov function. Moreover, considering the engineering application, the effect of measurement noise in the tilt angle sensors on the estimation accuracy of the EHGO is analyzed. Finally, the numerical simulation is performed to illustrate the validity of the method proposed in this paper.

  17. Spacecraft Angular Rates Estimation with Gyrowheel Based on Extended High Gain Observer.

    Science.gov (United States)

    Liu, Xiaokun; Yao, Yu; Ma, Kemao; Zhao, Hui; He, Fenghua

    2016-04-14

    A gyrowheel (GW) is a kind of electronic electric-mechanical servo system, which can be applied to a spacecraft attitude control system (ACS) as both an actuator and a sensor simultaneously. In order to solve the problem of two-dimensional spacecraft angular rate sensing as a GW outputting three-dimensional control torque, this paper proposed a method of an extended high gain observer (EHGO) with the derived GW mathematical model to implement the spacecraft angular rate estimation when the GW rotor is working at large angles. For this purpose, the GW dynamic equation is firstly derived with the second kind Lagrange method, and the relationship between the measurable and unmeasurable variables is built. Then, the EHGO is designed to estimate and calculate spacecraft angular rates with the GW, and the stability of the designed EHGO is proven by the Lyapunov function. Moreover, considering the engineering application, the effect of measurement noise in the tilt angle sensors on the estimation accuracy of the EHGO is analyzed. Finally, the numerical simulation is performed to illustrate the validity of the method proposed in this paper.

  18. Next Generation Astronomical X-ray Optics: High Angular Resolution, Light Weight, and Low Production Cost

    Science.gov (United States)

    Zhang. W. W.; Biskach, M. P.; Blake, P. N.; Chan, K. W.; Gaskin, J. A.; Hong, M. L.; Jones, W. D.; Kolos, L. D.; Mazzarella, J. R.; McClelland, R. S.; O'Dell, S. L.; Saha, T. T.; Sharpe, M. V.

    2012-01-01

    X-ray astronomy depends on the availability of telescopes with high resolution and large photon collecting areas. Since x-ray observation can only be carried out above the atmosphere, these telescopes must be necessarily lightweight. Compounding the lightweight requirement is that an x-ray telescope consists of many nested concentric shells, which further require that x-ray mirrors must also be geometrically thin to achieve high packing efficiency. This double lightweight and geometrically thin requirement poses significant technical challenges in fabricating the mirrors and in integrating them into mirror assemblies. This paper reports on the approach, strategy and status of our x-ray optics development program whose objective is to meet these technical challenges at modest cost to enable future x-ray missions, including small Explorer missions in the near term, probe class missions in the medium term, and large flagship missions in the long term.

  19. Molecular outflows and hot molecular cores in G24.78+0.08 at sub-arcsecond angular resolution

    Science.gov (United States)

    Beltrán, M. T.; Cesaroni, R.; Zhang, Q.; Galván-Madrid, R.; Beuther, H.; Fallscheer, C.; Neri, R.; Codella, C.

    2011-08-01

    Context. This study is part of a large project to study the physics of accretion and molecular outflows towards a selected sample of high-mass star-forming regions that show evidence of infall and rotation from previous studies. Aims: We wish to make a thorough study at high-angular resolution of the structure and kinematics of the HMCs and corresponding molecular outflows in the high-mass star-forming region G24.78+0.08. Methods: We carried out SMA and IRAM PdBI observations at 1.3 and 1.4 mm, respectively, of dust and of typical high-density and molecular outflow tracers with resolutions of < 1″. Complementary IRAM 30-m 12CO and 13CO observations were carried out to recover the short spacing information of the molecular outflows. Results: The millimeter continuum emission towards cores G24 A1 and A2 has been resolved into three and two cores, respectively, and named A1, A1b, A1c, A2, and A2b. All these cores are aligned in a southeast-northwest direction coincident with that of the molecular outflows detected in the region, which suggests a preferential direction for star formation in this region. The masses of the cores range from 7 to 22 M⊙, and the rotational temperatures from 128 to 180 K. The high-density tracers have revealed the existence of two velocity components towards A1. One of them peaks close to the position of the millimeter continuum peak and of the HC Hii region and is associated with the velocity gradient seen in CH3CN towards this core, while the other one peaks southwest of core A1 and is not associated with any millimeter continuum emission peak. The position-velocity plots along outflow A and the 13CO (2-1) averaged blueshifted and redshifted emission indicate that this outflow is driven by core A2. Core A1 apparently does not drive any outflow. The knotty appearance of the highly collimated outflow C and the 12CO position-velocity plot suggest an episodic outflow, where the knots are made of swept-up ambient gas.

  20. Angular-resolution and material-characterization measurements for a dual-particle imaging system with mixed-oxide fuel

    Energy Technology Data Exchange (ETDEWEB)

    Poitrasson-Rivière, Alexis, E-mail: alexispr@umich.edu [Department of Nuclear Engineering & Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Polack, J. Kyle; Hamel, Michael C.; Klemm, Dietrich D.; Ito, Kai; McSpaden, Alexander T.; Flaska, Marek; Clarke, Shaun D.; Pozzi, Sara A. [Department of Nuclear Engineering & Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Tomanin, Alice [Lainsa-Italia S.R.L., Via E. Fermi 2749, 21027 Ispra, VA (Italy); Peerani, Paolo [European Commission, Joint Research Centre, Institute for Transuranium Elements, 21027 Ispra, VA (Italy)

    2015-10-11

    A dual-particle imaging (DPI) system, capable of simultaneously imaging fast neutrons and gamma rays, has been operated in the presence of mixed-oxide (MOX) fuel to assess the system's angular resolution and material-characterization capabilities. The detection principle is based on the scattering physics of neutrons (elastic scattering) and gamma rays (Compton scattering) in organic and inorganic scintillators. The detection system is designed as a combination of a two-plane Compton camera and a neutron-scatter camera. The front plane consists of EJ-309 liquid scintillators and the back plane consists of interleaved EJ-309 and NaI(Tl) scintillators. MCNPX-PoliMi was used to optimize the geometry of the system and the resulting prototype was built and tested using a Cf-252 source as an SNM surrogate. A software package was developed to acquire and process data in real time. The software was used for a measurement campaign to assess the angular resolution of the imaging system with MOX samples. Measurements of two MOX canisters of similar isotopics and intensity were performed for 6 different canister separations (from 5° to 30°, corresponding to distances of 21 cm and 131 cm, respectively). The measurements yielded a minimum separation of 20° at 2.5 m (86-cm separation) required to see 2 separate hot spots. Additionally, the results displayed good agreement with MCNPX-PoliMi simulations. These results indicate an angular resolution between 15° and 20°, given the 5° step. Coupled with its large field of view, and its capability to differentiate between spontaneous fission and (α,n) sources, the DPI system shows its potential for nuclear-nonproliferation applications.

  1. Angular-resolution and material-characterization measurements for a dual-particle imaging system with mixed-oxide fuel

    Science.gov (United States)

    Poitrasson-Rivière, Alexis; Polack, J. Kyle; Hamel, Michael C.; Klemm, Dietrich D.; Ito, Kai; McSpaden, Alexander T.; Flaska, Marek; Clarke, Shaun D.; Pozzi, Sara A.; Tomanin, Alice; Peerani, Paolo

    2015-10-01

    A dual-particle imaging (DPI) system, capable of simultaneously imaging fast neutrons and gamma rays, has been operated in the presence of mixed-oxide (MOX) fuel to assess the system's angular resolution and material-characterization capabilities. The detection principle is based on the scattering physics of neutrons (elastic scattering) and gamma rays (Compton scattering) in organic and inorganic scintillators. The detection system is designed as a combination of a two-plane Compton camera and a neutron-scatter camera. The front plane consists of EJ-309 liquid scintillators and the back plane consists of interleaved EJ-309 and NaI(Tl) scintillators. MCNPX-PoliMi was used to optimize the geometry of the system and the resulting prototype was built and tested using a Cf-252 source as an SNM surrogate. A software package was developed to acquire and process data in real time. The software was used for a measurement campaign to assess the angular resolution of the imaging system with MOX samples. Measurements of two MOX canisters of similar isotopics and intensity were performed for 6 different canister separations (from 5° to 30°, corresponding to distances of 21 cm and 131 cm, respectively). The measurements yielded a minimum separation of 20° at 2.5 m (86-cm separation) required to see 2 separate hot spots. Additionally, the results displayed good agreement with MCNPX-PoliMi simulations. These results indicate an angular resolution between 15° and 20°, given the 5° step. Coupled with its large field of view, and its capability to differentiate between spontaneous fission and (α,n) sources, the DPI system shows its potential for nuclear-nonproliferation applications.

  2. Q-ball imaging models: comparison between high and low angular resolution diffusion-weighted MRI protocols for investigation of brain white matter integrity

    Energy Technology Data Exchange (ETDEWEB)

    Caiazzo, Giuseppina; Trojsi, Francesca; Cirillo, Mario; Tedeschi, Gioacchino [MRI Research Center SUN-FISM-Neurological Institute for Diagnosis and Care ' ' Hermitage Capodimonte' ' , Naples (Italy); Second University of Naples, Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, Naples (Italy); Esposito, Fabrizio [University of Salerno, Department of Medicine and Surgery, Baronissi (Salerno) (Italy); Maastricht University, Department of Cognitive Neuroscience, Maastricht (Netherlands)

    2016-02-15

    Q-ball imaging (QBI) is one of the typical data models for quantifying white matter (WM) anisotropy in diffusion-weighted MRI (DwMRI) studies. Brain and spinal investigation by high angular resolution DwMRI (high angular resolution imaging (HARDI)) protocols exhibits higher angular resolution in diffusion imaging compared to low angular resolution models, although with longer acquisition times. We aimed to assess the difference between QBI-derived anisotropy values from high and low angular resolution DwMRI protocols and their potential advantages or shortcomings in neuroradiology. Brain DwMRI data sets were acquired in seven healthy volunteers using both HARDI (b = 3000 s/mm{sup 2}, 54 gradient directions) and low angular resolution (b = 1000 s/mm{sup 2}, 32 gradient directions) acquisition schemes. For both sequences, tract of interest tractography and generalized fractional anisotropy (GFA) measures were extracted by using QBI model and were compared between the two data sets. QBI tractography and voxel-wise analyses showed that some WM tracts, such as corpus callosum, inferior longitudinal, and uncinate fasciculi, were reconstructed as one-dominant-direction fiber bundles with both acquisition schemes. In these WM tracts, mean percent different difference in GFA between the two data sets was less than 5 %. Contrariwise, multidirectional fiber bundles, such as corticospinal tract and superior longitudinal fasciculus, were more accurately depicted by HARDI acquisition scheme. Our results suggest that the design of optimal DwMRI acquisition protocols for clinical investigation of WM anisotropy by QBI models should consider the specific brain target regions to be explored, inducing researchers to a trade-off choice between angular resolution and acquisition time. (orig.)

  3. Large zenith angle observations with the high-resolution GRANITE III camera

    CERN Document Server

    Petry, D

    2001-01-01

    The GRANITE III camera of the Whipple Cherenkov Telescope at the Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona (2300 m a.s.l.) has the highest angular resolution of all cameras used on this telescope so far. The central region of the camera has 379 pixels with an individual angular diameter of 0.12 degrees. This makes the instrument especially suitable for observations of gamma-induced air-showers at large zenith angles since the increase in average distance to the shower maximum leads to smaller shower images in the focal plane of the telescope. We examine the performance of the telescope for observations of gamma-induced air-showers at zenith angles up to 63 degrees based on observations of Mkn 421 and using Monte Carlo Simulations. An improvement to the standard data analysis is suggested.

  4. Visibility based angular power spectrum estimation in low frequency radio interferometric observations

    CERN Document Server

    Choudhuri, Samir; Ghosh, Abhik; Ali, SK Saiyad

    2014-01-01

    We present two estimators to quantify the angular power spectrum of the sky signal directly from the visibilities measured in radio interferometric observations. This is relevant for both the foregrounds and the cosmological 21-cm signal buried therein. The discussion here is restricted to the Galactic synchrotron radiation, the most dominant foreground component after point source removal. Our theoretical analysis is validated using simulations at 150 MHz, mainly for GMRT and also briefly for LOFAR. The Bare Estimator uses pairwise correlations of the measured visibilities, while the Tapered Gridded Estimator uses the visibilities after gridding in the uv plane. The former is very precise, but computationally expensive for large data. The latter has a lower precision, but takes less computation time which is proportional to the data volume. The latter also allows tapering of the sky response leading to sidelobe suppression, an useful ingredient for foreground removal. Both estimators avoid the positive bias ...

  5. Large Angular Jump Mechanism Observed for Hydrogen Bond Exchange in Aqueous Perchlorate Solution

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Minbiao; /SLAC, PULSE /Stanford U., Phys. Dept.; Odelius3, Michael; /Stockholm U.; Gaffney1, K.J.; /aff SLAC, PULSE

    2010-06-11

    The mechanism for hydrogen bond (H-bond) switching in solution has remained subject to debate despite extensive experimental and theoretical studies. We have applied polarization-selective multidimensional vibrational spectroscopy to investigate the H-bond exchange mechanism in aqueous NaClO{sub 4} solution. The results show that a water molecule shifts its donated H-bonds between water and perchlorate acceptors by means of large, prompt angular rotation. Using a jump-exchange kinetic model, we extract an average jump angle of 49 {+-} 4{sup o}, in qualitative agreement with the jump angle observed in molecular dynamics simulations of the same aqueous NaClO{sub 4} solution.

  6. Angular distributions of photon stimulated desorption in a vacuum duct observed by using a unidirectional detector

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, M.; Matumoto, M.; Ueda, S.

    1987-07-01

    Pressures in the vacuum duct of the electron storage rings depend on photodesorption. A multicapillary-type mass spectrometer was applied to observe local outgassing rates in the duct, in which the duct surfaces were irradiated by directly incident photons and/or by scattered photons. Local outgassing rates were nonuniform along the periphery of the duct. The desorption rates at the directly incident point were higher than at the other surfaces when photon dose was less than 200 mA h. At over 9000 mA h the rates at that point decreased more, while the desorption rates at the other surfaces decreased less. Angular distributions of photocurrent were also measured. The distributions were almost uniform except near the directly incident point.

  7. Quantum beats in the 3{gamma} annihilation decay of Positronium observed by perturbed angular distribution

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Eugeniu [National Institute for Nuclear Physics and Engineering - Horia Hulubei, Bucharest - Magurele, CP MG 06, Atomistilor Street 407 (Romania); Center for Advanced Studies in Physics of the Roumanian Academy, Casa Academiei Romane, Calea 13 Septembrie No: 13, Bucharest (Romania); Vata, Ion [National Institute for Nuclear Physics and Engineering - Horia Hulubei, Bucharest - Magurele, CP MG 06, Atomistilor Street 407 (Romania)], E-mail: vata@ifin.nipne.ro; Dudu, Dorin; Rusen, Ion; Stefan, Nitisor [National Institute for Nuclear Physics and Engineering - Horia Hulubei, Bucharest - Magurele, CP MG 06, Atomistilor Street 407 (Romania)

    2008-10-31

    We have applied conventional Time Differential Perturbed Angular Correlation (TDPAC) method to observe the anisotropy oscillations in the 3{gamma} annihilation decay of polarized Positronium in a weak magnetic field. The effect, as predicted theoretically and experimentally demonstrated by Barishevsky et al. [V.G. Barishevsky, O.N. Metelitsa, V.V. Tikhomirov, Oscillations of the positronium decay {gamma}-quantum angular distribution in a magnetic field, J. Phys. B: At. Mol. Opt. Phys.22 (1989) 2835], is induced by the coherent admixture of the m = 0 states of ortho-Positronium (o-Ps) and para-Positronium (p-Ps) in interaction with the magnetic field. The following experimental characteristics are to be considered: (i)the oscillation frequency corresponds to the difference in energy of the Ps atom levels in magnetic field and is proportional with H{sup 2}; (ii)in a fixed geometry the modulation depth (oscillations amplitude) depends on the mean positron polarization; (iii)privileged angles of the polarization vector, magnetic field and detectors are required for optimizing the observed oscillations amplitude. The normalized difference spectrum function (R(t)) obtained from time spectra measured in vacuum and in different gaseous atmospheres (Ar, H{sub 2}, N{sub 2}) have the oscillations amplitude constant and we conclude that the Ps atoms are not fully thermalized over a time interval of about 400 ns. The R(t) functions obtained for o-Ps annihilation decays, in dry air or Ar-O mixture, have the oscillations amplitude time dependent due, probably, to the paramagnetism of the Oxygen molecules.

  8. The role of dislocations in varied olivine deformation mechanisms investigated using high-angular resolution electron backscatter diffraction

    Science.gov (United States)

    Wallis, David; Hansen, Lars; Britton, Ben; Wilkinson, Angus

    2016-04-01

    Experimentally-derived flow laws can be used to predict the rheology of rocks deformed under natural conditions only if the same microphysical processes can be demonstrated to control the rate-limiting deformation mechanism in both cases. Olivine rheology may exert a principle control on the strength of the lithosphere, and therefore considerable research effort has been applied to assessing its rheology through experimental, geological, and geophysical approaches. Nonetheless, considerable uncertainty remains regarding the dominant deformation mechanisms in the upper mantle. This uncertainty arises in large part due to our limited understanding of the fundamental deformation processes associated with each mechanism. Future improvements to microphysical models of distinct deformation mechanisms require new insight into the contributions those fundamental processes to the macroscopic behaviour. The dynamics of dislocations is central to modelling viscous deformation of olivine, but characterisation techniques capable of constraining dislocation types, densities, and distributions over the critical grain to polycrystal length-scales have been lacking. High angular resolution electron backscatter diffraction (HR-EBSD), developed and increasingly applied in the material sciences, offers an approach capable of such analyses. HR-EBSD utilises diffraction pattern image cross-correlation to achieve dramatically improved angular resolution (~0.01°) of lattice orientation gradients compared to conventional Hough-based EBSD (~0.5°). This angular resolution allows very low densities (≥ 10^11 m^-2) of geometrically necessary dislocations (GND) to be resolved, facilitating analysis of a wide range of dislocation microstructures. We have developed the application of HR-EBSD to olivine and applied it to samples deformed both experimentally and naturally in grain-size sensitive and grain-size insensitive regimes. The results quantitatively highlight variations in the types and

  9. Diffeomorphic Metric Mapping of High Angular Resolution Diffusion Imaging based on Riemannian Structure of Orientation Distribution Functions

    CERN Document Server

    Du, Jia; Qiu, Anqi

    2011-01-01

    In this paper, we propose a novel large deformation diffeomorphic registration algorithm to align high angular resolution diffusion images (HARDI) characterized by orientation distribution functions (ODFs). Our proposed algorithm seeks an optimal diffeomorphism of large deformation between two ODF fields in a spatial volume domain and at the same time, locally reorients an ODF in a manner such that it remains consistent with the surrounding anatomical structure. To this end, we first review the Riemannian manifold of ODFs. We then define the reorientation of an ODF when an affine transformation is applied and subsequently, define the diffeomorphic group action to be applied on the ODF based on this reorientation. We incorporate the Riemannian metric of ODFs for quantifying the similarity of two HARDI images into a variational problem defined under the large deformation diffeomorphic metric mapping (LDDMM) framework. We finally derive the gradient of the cost function in both Riemannian spaces of diffeomorphis...

  10. POLAR spacecraft observations of helium ion angular anisotropy in the Earth's radiation belts

    Directory of Open Access Journals (Sweden)

    W. N. Spjeldvik

    Full Text Available New observations of energetic helium ion fluxes in the Earth's radiation belts have been obtained with the CAMMICE/HIT instrument on the ISTP/GGS POLAR spacecraft during the extended geomagnetically low activity period April through October 1996. POLAR executes a high inclination trajectory that crosses over both polar cap regions and passes over the geomagnetic equator in the heart of the radiation belts. The latter attribute makes possible direct observations of nearly the full equatorial helium ion pitch angle distributions in the heart of the Earth's radiation belt region. Additionally, the spacecraft often re-encounters the same geomagnetic flux tube at a substantially off-equatorial location within a few tens of minutes prior to or after the equatorial crossing. This makes both the equatorial pitch angle distribution and an expanded view of the local off-equatorial pitch angle distribution observable. The orbit of POLAR also permitted observations to be made in conjugate magnetic local time sectors over the course of the same day, and this afforded direct comparison of observations on diametrically opposite locations in the Earth's radiation belt region at closely spaced times. Results from four helium ion data channels covering ion kinetic energies from 520 to 8200 KeV show that the distributions display trapped particle characteristics with angular flux peaks for equatorially mirroring particles as one might reasonably expect. However, the helium ion pitch angle distributions generally flattened out for equatorial pitch angles below about 45°. Significant and systematic helium ion anisotropy difference at conjugate magnetic local time were also observed, and we report quiet time azimuthal variations of the anisotropy index.

    Key words. Magnetospheric physics (energetic particles · trapped; magnetospheric configuration and dynamics; plasmasphere

  11. Estimating small angular scale CMB anisotropy with high resolution N-body simulations: weak lensing

    CERN Document Server

    Fullana, M J; Thacker, R J; Couchman, H M P; Sáez, D

    2010-01-01

    We estimate the impact of weak lensing by strongly nonlinear cosmological structures on the cosmic microwave background. Accurate calculation of large $\\ell$ multipoles requires N-body simulations and ray-tracing schemes with both high spatial and temporal resolution. To this end we have developed a new code that combines a gravitational Adaptive Particle-Particle, Particle-Mesh (AP3M) solver with a weak lensing evaluation routine. The lensing deviations are evaluated while structure evolves during the simulation so that all evolution steps--rather than just a few outputs--are used in the lensing computations. The new code also includes a ray-tracing procedure that avoids periodicity effects in a universe that is modeled as a 3-D torus in the standard way. Results from our new simulations are compared with previous ones based on Particle-Mesh simulations. We also systematically investigate the impact of box volume, resolution, and ray-tracing directions on the variance of the computed power spectra. We find t...

  12. Determining the dominant partial wave contributions from angular distributions of single- and double-polarization observables in pseudoscalar meson photoproduction

    CERN Document Server

    Wunderlich, Y; Thiel, A; Beck, R

    2016-01-01

    This work presents a simple method to determine the significant partial wave contributions to experimentally determined observables in pseudoscalar meson photoproduction. First, fits to angular distributions are presented and the maximum orbital angular momentum $\\text{L}_{\\mathrm{max}}$ needed to achieve a good fit is determined. Then, recent polarization measurements for $\\gamma p \\rightarrow \\pi^{0} p$ from ELSA, GRAAL, JLab and MAMI are investigated according to the proposed method. This method allows us to project high-spin partial wave contributions to any observable as long as the measurement has the necessary statistical accuracy. We show, that high precision and large angular coverage in the polarization data are needed in order to be sensitive to high-spin resonance-states and thereby also for the finding of small resonance contributions. This task can be achieved via interference of these resonances with the well-known states. For the channel $\\gamma p \\rightarrow \\pi^{0} p$, those are the $N(1680)...

  13. Angular observation of joints of geckos moving on horizontal and vertical surfaces

    Institute of Scientific and Technical Information of China (English)

    LI HongKai; DAI ZhenDong; SHI AiJu; ZHANG Hao; SUN JiuRong

    2009-01-01

    Because of their outstanding climbing and motor coordination ability, geckos have provided the basis for a peculiar bionic model leading to the development of a gecko-robot. A three-dimensional locomo-tion observation system was constructed to measure angular orientations of joints while geckos trotted (337.1 mm/s) and walked (66.7 mm/s) on horizontal surfaces, and trotted (241.5mm/s) and walked (30.6mm/s) on vertical surfaces. Moving over horizontal surfaces, the joints rotated more quickly the greater the speed, and the swinging scope of forelimbs stayed nearly at 59 degrees when swinging forward, but extended from 72 degrees to 79.2 degrees when swinging backward. The lifting angle of forelimbs was always positive to keep the center of mass close to the surface when moving up vertical surfaces, the scope of the forward swinging forelimbs forward extended from 33.7 degrees to 36.7 de-grees with increasing speed, while the scope of backward swinging forelimbs remained almost the same at 87.5 degrees. Alternative gaits had little effect on the swing angle of hindlimbs of the geckos moving on both horizontal and vertical surfaces.

  14. Development of high angular resolution x-ray telescopes based on slumped glass foils

    Science.gov (United States)

    Ghigo, M.; Basso, S.; Borsa, F.; Citterio, O.; Civitani, M.; Conconi, P.; Pagano, G.; Pareschi, G.; Proserpio, L.; Salmaso, B.; Sironi, G.; Spiga, D.; Tagliaferri, G.; Zambra, A.; Parodi, G.; Martelli, F.; Gallieni, D.; Tintori, M.; Bavdaz, M.; Wille, E.

    2012-09-01

    The mirrors of the International X-ray Observatory (IXO) were based on a large number of high quality segments, aiming at achieving a global spatial resolution better than 5” HEW while giving a large collecting area (around 3m2@ 1 keV). A study concerning the hot slumping of thin glass foils was started in Europe, funded by ESA and led by the Brera Astronomical Observatory (INAF-OAB), for the development of a replication technology based on glass material. The study is currently continuing even after the IXO program has been descoped and renamed ATHENA, in the perspective of using the technology under development for other future missions or applications. INAF-OAB efforts have been focused on the "Direct" slumping approach with convex moulds, meaning that during the thermal cycle the optical surface of the glass is in direct contact with the mould surface. The single mirror segments are made of thin glass plates (0.4 mm thick), with a reflecting area of 200 mm × 200 mm. The adopted integration process foresees the use of glass reinforcing ribs for bonding together the plates in such a way to form a rigid and stiff stack of segmented mirror shells; the stack is supported by a thick backplane. During the bonding process, the plates are constrained in close contact with the surface of a precisely figured integration master by the application of vacuum pump suction. In this way, the springback deformations and the low frequency errors still present in the plates' profile after slumping can be corrected. The status of the technology development is presented in this paper, together with the description and metrology of the prototypes already realized or under construction at the Observatory laboratories.

  15. Observer dependence of angular momentum in general relativity and its relationship to the gravitational-wave memory effect

    CERN Document Server

    Flanagan, Éanna É

    2014-01-01

    We define a procedure by which observers can measure type of special-relativistic linear and angular momentum $(P^a, J^{ab})$ at a point in a curved spacetime using only the spacetime geometry in a neighborhood of that point. The method is chosen to yield the conventional results in stationary spacetimes near future null infinity. We also explore the extent to which spatially separated observers can compare the values of angular momentum that they measure and find consistent results. We define a generalization of parallel transport along curves which gives a prescription for transporting angular momentum values along curves, in such a way that it gives back the correct prescription in special relativity. If observers use this prescription, then they will find that the angular momenta they measure are observer dependent, because of the effects of spacetime curvature. The observer dependence can be quantified by a kind of generalized holonomy. We show that bursts of gravitational waves with memory generically g...

  16. Young massive stars and their environment in the mid-infrared at high angular resolution

    Energy Technology Data Exchange (ETDEWEB)

    Wit, W J de; Hoare, M G; Oudmaijer, R D [School of Physics and Astronomy, University of Leeds, LS2 9JT (United Kingdom); Fujiyoshi, T [Subaru Telescope, NAOJ, 650 North A' ohoku Place, Hilo, HI 96720 (United States)], E-mail: w.j.m.dewit@leeds.ac.uk

    2008-10-15

    We present interferometric and single-dish mid-infrared observations of a sample of massive young stellar objects (BN-type objects), using VLTI-MIDI (10{mu}m) and Subaru-COMICS (24.5 {mu}m). We discuss the regions S140, Mon R2, M8E-IR, and W33A. The observations probe the inner regions of the dusty envelope at scales of 50 milli arcsecond and 0.6'' ({approx}100-1000 AU), respectively. Simultaneous model fits to spectral energy distributions and spatial data are achieved using self-consistent spherical envelope modelling. We conclude that those MYSO envelopes that are best described by a spherical geometry, the commensurate density distribution is a powerlaw with index -1.0. Such a powerlaw is predicted if the envelope is supported by turbulence on the 100-1000 AU scales probed with MIDI and COMICS, but the role of rotation at these spatial scales need testing.

  17. The donor of Aquila X-1 revealed by high-angular resolution near-infrared spectroscopy

    Science.gov (United States)

    Mata Sánchez, D.; Muñoz-Darias, T.; Casares, J.; Jiménez-Ibarra, F.

    2017-01-01

    The low-mass X-ray binary Aquila X-1 is one of the most active neutron star X-ray transients. Despite its relatively bright quiescent optical counterpart, the detection of its companion has been hampered by the presence of a nearby interloper star. Using the Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI) on the Very Large Telescope-8.2m telescope, we unambiguously single out Aquila X-1 from the interloper. Phase-resolved near-infrared spectroscopy reveals absorption features from a K4 ± 2 companion star moving at a projected velocity of K2 = 136 ± 4 km s- 1. We here present the first dynamical solution and associated fundamental parameters of Aquila X-1, imposing new constraints on the orbital inclination (36° star transient.

  18. Properties of dense cores in clustered massive star-forming regions at high angular resolution

    CERN Document Server

    Sanchez-Monge, Alvaro; Fontani, Francesco; Busquet, Gemma; Juarez, Carmen; Estalella, Robert; Tan, Jonathan C; Sepulveda, Inma; Ho, Paul T P; Zhang, Qizhou; Kurtz, Stan

    2013-01-01

    We aim at characterising dense cores in the clustered environments associated with massive star-forming regions. For this, we present an uniform analysis of VLA NH3(1,1) and (2,2) observations towards a sample of 15 massive star-forming regions, where we identify a total of 73 cores, classify them as protostellar, quiescent starless, or perturbed starless, and derive some physical properties. The average sizes and ammonia column densities are 0.06 pc and 10^15 cm^-2, respectively, with no significant differences between the starless and protostellar cores, while the linewidth and rotational temperature of quiescent starless cores are smaller, 1.0 km/s and 16 K, than those of protostellar (1.8 km/s, 21 K), and perturbed starless (1.4 km/s, 19 K) cores. Such linewidths and temperatures for these quiescent starless cores in the surroundings of massive stars are still significantly larger than the typical values measured in starless cores of low-mass star-forming regions, implying an important non-thermal compone...

  19. The complex evolutionary paths of local infrared bright galaxies: a high angular resolution mid-infrared view

    CERN Document Server

    Alonso-Herrero, A; Roche, P F; Hernan-Caballero, A; Aretxaga, I; Martinez-Paredes, M; Almeida, C Ramos; Pereira-Santaella, M; Diaz-Santos, T; Levenson, N A; Packham, C; Colina, L; Esquej, P; Gonzalez-Martin, O; Ichikawa, K; Imanishi, M; Espinosa, J M Rodriguez; Telesco, C

    2016-01-01

    We investigate the evolutionary connection between local IR-bright galaxies ($\\log L_{\\rm IR}\\ge 11.4\\,L_\\odot$) and quasars. We use high angular resolution ($\\sim$ 0.3-0.4 arcsec $\\sim$ few hundred parsecs) $8-13\\,\\mu$m ground-based spectroscopy to disentangle the AGN mid-IR properties from those of star formation. The comparison between the nuclear $11.3\\,\\mu$m PAH feature emission and that measured with Spitzer/IRS indicates that the star formation is extended over a few kpc in the IR-bright galaxies. The AGN contribution to the total IR luminosity of IR-bright galaxies is lower than in quasars. Although the dust distribution is predicted to change as IR-bright galaxies evolve to IR-bright quasars and then to optical quasars, we show that the AGN mid-IR emission of all the quasars in our sample is not significantly different. In contrast, the nuclear emission of IR-bright galaxies with low AGN contributions appears more heavily embedded in dust although there is no clear trend with the interaction stage or...

  20. Nuclear star formation on 100 parsec scales: 10" resolution radio continuum, HI and CO observations

    Science.gov (United States)

    Turner, Jean L.; Ho, Paul T. P.; Martin, Robert N.

    1987-01-01

    A program of radio line and continuum studies of star formation in nearby spiral galaxies is reported. The objective is a search for hot gas and peculiar dynamics in spiral nuclei with 10" to 30" angular resolution. Vigorous star formation is found to be a common phenomenon in the inner kpc of spirals. Arcsecond resolution observations of radio continuum emission at 6 and 2 cm were used to separate the thermal and nonthermal radio components. It was found that thermal and nonthermal emission are well mixed even on sizescales of 10 pc. To understand the reason for the increased level of star formation activity in spiral nuclei, HI and CO emission in these galaxies is studied. The CO transition was detected in M51, M82, NGC 253, NGC 6946 and IC 342 with T sub a approx. 0.5 to 2.0 K, at 20" angular resolution. The dynamics and spatial distribution of nuclear gas are being studied using VLA HI maps with 30" synthesized beams. Evidence for noncircular motions in HI was found in the nucleus of IC 342.

  1. Discovery potential of xenon-based neutrinoless double beta decay experiments in light of small angular scale CMB observations

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Cadenas, J.J.; Martín-Albo, J.; Vidal, J. Muñoz; Peña-Garay, C., E-mail: gomez@mail.cern.ch, E-mail: jmalbos@ific.uv.es, E-mail: jmunoz@ific.uv.es, E-mail: penya@ific.uv.es [Instituto de Física Corpuscular (IFIC), CSIC and Universitat de Valencia Calle Catedrático José Beltrán, 2, 46090 Paterna, Valencia (Spain)

    2013-03-01

    The South Pole Telescope (SPT) has probed an expanded angular range of the CMB temperature power spectrum. Their recent analysis of the latest cosmological data prefers nonzero neutrino masses, with Σm{sub ν} = (0.32±0.11) eV. This result, if confirmed by the upcoming Planck data, has deep implications on the discovery of the nature of neutrinos. In particular, the values of the effective neutrino mass m{sub ββ} involved in neutrinoless double beta decay (ββ0ν) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based ββ0ν experiments, on the double grounds of their good performance and the suitability of the technology to large-mass scaling. We show that the current generation, with effective masses in the range of 100 kg and conceivable exposures in the range of 500 kg·year, could already have a sizeable opportunity to observe ββ0ν events, and their combined discovery potential is quite large. The next generation, with an exposure in the range of 10 ton·year, would have a much more enhanced sensitivity, in particular due to the very low specific background that all the xenon technologies (liquid xenon, high-pressure xenon and xenon dissolved in liquid scintillator) can achieve. In addition, a high-pressure xenon gas TPC also features superb energy resolution. We show that such detector can fully explore the range of allowed effective Majorana masses, thus making a discovery very likely.

  2. Calibration of Herschel SPIRE FTS observations at different spectral resolutions

    CERN Document Server

    Marchili, N; Fulton, T; Polehampton, E T; Valtchanov, I; Zaretski, J; Naylor, D A; Griffin, M J; Imhof, P; Lim, T; Lu, N; Makiwa, G; Pearson, C; Spencer, L

    2016-01-01

    The SPIRE Fourier Transform Spectrometer on board the Herschel Space Observatory had two standard spectral resolution modes for science observations: high resolution (HR) and low resolution (LR), which could also be performed in sequence (H+LR). A comparison of the HR and LR resolution spectra taken in this sequential mode, revealed a systematic discrepancy in the continuum level. Analysing the data at different stages during standard pipeline processing, demonstrates the telescope and instrument emission affect HR and H+LR observations in a systematically different way. The origin of this difference is found to lie in the variation of both the telescope and instrument response functions, while it is triggered by fast variation of the instrument temperatures. As it is not possible to trace the evolution of the response functions through auxiliary housekeeping parameters, the calibration cannot be corrected analytically. Therefore an empirical correction for LR spectra has been developed, which removes the sys...

  3. PKS 1502+106: A high-redshift Fermi blazar at extreme angular resolution. Structural dynamics with VLBI imaging up to 86 GHz

    CERN Document Server

    Karamanavis, V; Krichbaum, T P; Angelakis, E; Hodgson, J; Nestoras, I; Myserlis, I; Zensus, J A; Sievers, A; Ciprini, S

    2016-01-01

    Context. Blazars are among the most energetic objects in the Universe. In 2008 August, Fermi/LAT detected the blazar PKS 1502+106 showing a rapid and strong gamma-ray outburst followed by high and variable flux over the next months. This activity at high energies triggered an intensive multi-wavelength campaign covering also the radio, optical, UV, and X-ray bands indicating that the flare was accompanied by a simultaneous outburst at optical/UV/X-rays and a delayed outburst at radio bands. Aims: In the current work we explore the phenomenology and physical conditions within the ultra-relativistic jet of the gamma-ray blazar PKS 1502+106. Additionally, we address the question of the spatial localization of the MeV/GeV-emitting region of the source. Methods: We utilize ultra-high angular resolution mm-VLBI observations at 43 and 86 GHz complemented by VLBI observations at 15 GHz. We also employ single-dish radio data from the F-GAMMA program at frequencies matching the VLBI monitoring. Results: PKS 1502+106 sh...

  4. ALMA Observations of Asteroid 3 Juno at 60 Kilometer Resolution

    CERN Document Server

    Partnership, ALMA; Kneissl, R; Moullet, A; Brogan, C L; Fomalont, E B; Vlahakis, C; Asaki, Y; Barkats, D; Dent, W R F; Hills, R; Hirota, A; Hodge, J A; Impellizzeri, C M V; Liuzzo, E; Lucas, R; Marcelino, N; Matsushita, S; Nakanishi, K; Perez, L M; Phillips, N; Richards, A M S; Toledo, I; Aladro, R; Broguiere, D; Cortes, J R; Cortes, P C; Dhawan, V; Espada, D; Galarza, F; Garcia-Appadoo, D; Guzman-Ramirez, L; Hales, A S; Humphreys, E M; Jung, T; Kameno, S; Laing, R A; Leon, S; Marconi, G; Nikolic, B; Nyman, L -A; Radiszcz, M; Remijan, A; Rodon, J A; Sawada, T; Takahashi, S; Tilanus, R P J; Vilaro, B Vila; Watson, L C; Wiklind, T; de Gregorio, I; Di Francesco, J; Mangum, J; Francke, H; Gallardo, J; Garcia, J; Gonzalez, S; Hill, T; Kaminski, T; Kurono, Y; Lopez, C; Morales, F; Plarre, K; Randall, S; van kempen, T; Videla, L; Villard, E; Andreani, P; Hibbard, J E; Tatematsu, K

    2015-01-01

    We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm continuum images of the asteroid 3 Juno obtained with an angular resolution of 0.042 arcseconds (60 km at 1.97 AU). The data were obtained over a single 4.4 hr interval, which covers 60% of the 7.2 hr rotation period, approximately centered on local transit. A sequence of ten consecutive images reveals continuous changes in the asteroid's profile and apparent shape, in good agreement with the sky projection of the three-dimensional model of the Database of Asteroid Models from Inversion Techniques. We measure a geometric mean diameter of 259pm4 km, in good agreement with past estimates from a variety of techniques and wavelengths. Due to the viewing angle and inclination of the rotational pole, the southern hemisphere dominates all of the images. The median peak brightness temperature is 215pm13 K, while the median over the whole surface is 197pm15 K. With the unprecedented resolution of ALMA, we find that the brightness temperature varies ...

  5. Thin monolithic glass shells for future high angular resolution and large collecting area x-ray telescope

    Science.gov (United States)

    Civitani, M. M.; Citterio, O.; Ghigo, M.; Mattaini, E.; Pareschi, G.; Parodi, G.

    2013-09-01

    One of the most difficult requests to be accomplished from the technological point of view for next generation x-ray telescopes is to combine high angular resolution and effective area. A significant increase of effective area can be reached with high precision but at the same time thin (2-3 mm thickness for mirror diameters of 30-110 cm) glass mirror shells. In the last few years the Brera Observatory has lead a development program for realizing this kind of monolithic thin glass shell. The fused silica has been chosen as shell substrate due to its thermal and mechanical properties. To bring the mirror shells to the needed accuracy, we have adopted a deterministic direct polishing method (already used for past missions as Einstein, Rosat, Chandra) to ten time thinner shells. The technological challenge has been solved using a temporary stiffening structure that allows the handling and the machining of so thin glass shells. The results obtained with a prototype shell at an intermediate stage of its development (17'' HEW measured in full illumination mode with x-ray) indicate that the working concept is feasible and can be further exploited using the very large Ion Beam Facility available in our labs for the final high accuracy figuring of the thin shells. In this paper we present the required tolerances for the shell realization, the shells production chain flow and the ion beam facility up grading. Forecast on figuring time and expected performances of the figuring will also be given on the basis on the metrological data collected during past shell development.

  6. New High-Resolution Sunyaev-Zel'dovich Observations with GBT+MUSTANG

    CERN Document Server

    Mroczkowski, Tony; Dicker, Simon; Korngut, Phillip; Mason, Brian; Reese, Erik; Sarazin, Craig; Sievers, Jonathon; Sun, Ming; Young, Alex

    2011-01-01

    We present recent high angular resolution (9") Sunyaev-Zel'dovich effect (SZE) observations with MUSTANG, a 90-GHz bolometric receiver on the Green Bank Telescope. MUSTANG has now imaged several massive clusters of galaxies in some of the highest-resolution SZE imaging to date, revealing complex pressure substructure within the hot intra-cluster gas in merging clusters. We focus on three merging, intermediate redshift clusters here: MACS J0744.8+3927, MACS J0717.5+3745, RX J1347.5-1145. In one of these merging clusters, MACS J0744.8+3927, the MUSTANG observation has revealed shocked gas that was previously undetected in X-ray observations. Our preliminary results for MACS J0717.5+3745 demonstrate the complementarity these observations provide when combined with X-ray observations of the thermal emission and radio observations of the non-thermal emission. And finally, by revisiting RX J1347.5-1145, we note an inter- esting correlation between its radio emission and the SZE data. While observations of the therm...

  7. A Super-high Angular Resolution Principle for Coded-mask X-ray Imaging Beyond the Diffraction Limit of Single Pinhole

    CERN Document Server

    Zhang, Chen

    2008-01-01

    High angular resolution X-ray imaging is always demanded by astrophysics and solar physics, which can be realized by coded-mask imaging with very long mask-detector distance in principle. Previously the diffraction-interference effect has been thought to degrade coded-mask imaging performance dramatically at low energy end with very long mask-detector distance. In this work the diffraction-interference effect is described with numerical calculations, and the diffraction-interference cross correlation reconstruction method (DICC) is developed in order to overcome the imaging performance degradation. Based on the DICC, a super-high angular resolution principle (SHARP) for coded-mask X-ray imaging is proposed. The feasibility of coded mask imaging beyond the diffraction limit of single pinhole is demonstrated with simulations. With the specification that the mask element size of 50* 50 square micrometers and the mask-detector distance of 50 m, the achieved angular resolution is 0.32 arcsec above about 10 keV, an...

  8. Unambiguous observation of F-atom core-hole localization in CF4 through body-frame photoelectron angular distributions

    Science.gov (United States)

    McCurdy, C. W.; Rescigno, T. N.; Trevisan, C. S.; Lucchese, R. R.; Gaire, B.; Menssen, A.; Schöffler, M. S.; Gatton, A.; Neff, J.; Stammer, P. M.; Rist, J.; Eckart, S.; Berry, B.; Severt, T.; Sartor, J.; Moradmand, A.; Jahnke, T.; Landers, A. L.; Williams, J. B.; Ben-Itzhak, I.; Dörner, R.; Belkacem, A.; Weber, Th.

    2017-01-01

    A dramatic symmetry breaking in K -shell photoionization of the CF4 molecule in which a core-hole vacancy is created in one of four equivalent fluorine atoms is displayed in the molecular frame angular distribution of the photoelectrons. Observing the photoejected electron in coincidence with an F+ atomic ion after Auger decay is shown to select the dissociation path where the core hole was localized almost exclusively on that atom. A combination of measurements and ab initio calculations of the photoelectron angular distribution in the frame of the recoiling CF3+ and F+ atoms elucidates the underlying physics that derives from the Ne-like valence structure of the F(1 s-1 ) core-excited atom.

  9. High-angular resolution observations towards OMC-2 FIR 4: Dissecting an intermediate-mass protocluster

    NARCIS (Netherlands)

    A. López-Sepulcre; V. Taquet; A. Sánchez-Monge; C. Ceccarelli; C. Dominik; M. Kama; E. Caux; F. Fontani; A. Fuente; P.T.P. Ho; R. Neri; Y. Shimajiri

    2013-01-01

    Context. Intermediate-mass stars are an important ingredient of our Galaxy and a key to understanding how high- and low-mass stars form in clusters. One of the closest known young intermediate-mass protoclusters is OMC-2 FIR 4, which is located at a distance of 420 pc in Orion. This region is one of

  10. Observation of giant Goos-Hänchen and angular shifts at designed metasurfaces

    Science.gov (United States)

    Yallapragada, Venkata Jayasurya; Ravishankar, Ajith P.; Mulay, Gajendra L.; Agarwal, Girish S.; Achanta, Venu Gopal

    2016-01-01

    Metasurfaces with sub-wavelength features are useful in modulating the phase, amplitude or polarization of electromagnetic fields. While several applications are reported for light manipulation and control, the sharp phase changes would be useful in enhancing the beam shifts at reflection from a metasurface. In designed periodic patterns on metal film, at surface plasmon resonance, we demonstrate Goos-Hanchen shift of the order of 70 times the incident wavelength and the angular shifts of several hundred microradians. We have designed the patterns using rigorous coupled wave analysis (RCWA) together with S-matrices and have used a complete vector theory to calculate the shifts as well as demonstrate a versatile experimental setup to directly measure the shifts. The giant shifts demonstrated could prove to be useful in enhancing the sensitivity of experiments ranging from atomic force microscopy to gravitational wave detection.

  11. Learning from observations of the microwave background at small angular scales

    CERN Document Server

    Sáez, D

    1996-01-01

    In this paper, we focus our attention on the following question: How well can we recover the power spectrum of the cosmic microwave background from the maps of a given experiment?. Each experiment is described by a a pixelization scale, a beam size, a noise level and a sky coverage. We use accurate numerical simulations of the microwave sky and a cold dark matter model for structure formation in the universe. Angular scales smaller than those of previous simulations are included. The spectrum obtained from the simulated maps is appropriately compared with the theoretical one. Relative deviations between these spectra are estimated. Various contributions to these deviations are analyzed. The method used for spectra comparisons is discussed.

  12. Observation of a Change in Bend of an RNA Kissing Complex Using the Angular Dependence of Fluorescence Resonance Energy Transfer

    CERN Document Server

    Rahmanseresht, Sheema; Gamari, Ben D; Goldner, Lori S

    2014-01-01

    We report on the observation of a change in the bend angle of an RNA kissing complex upon Rop binding using single-molecular-pair FRET. The angular relationship between the dyes, rather than the distance between them, is shown to be responsible for the observed change in energy transfer. It has long been thought that Rop increases the bend angle of the R1inv-R2inv complex upon binding, but this has never been directly observed. In contrast, we find an increase in FRET upon the addition of Rop that is shown via modeling to be consistent with a decrease in the bend angle of the complex of $-15^{\\circ}\\pm7^{\\circ}$. The model predicts FRET from dye trajectories generated using molecular dynamics simulations of Cy3 and Cy5 attached to $5'$ terminal cytosine or guanosine on RNA. While FRET is commonly used to observe global changes in molecular structure attributed to changes in the distance between dyes, it is rarely, if ever, used to elucidate angular changes. Subtle global changes in molecular structure upon bi...

  13. Calibration of Herschel SPIRE FTS observations at different spectral resolutions

    Science.gov (United States)

    Marchili, N.; Hopwood, R.; Fulton, T.; Polehampton, E. T.; Valtchanov, I.; Zaretski, J.; Naylor, D. A.; Griffin, M. J.; Imhof, P.; Lim, T.; Lu, N.; Makiwa, G.; Pearson, C.; Spencer, L.

    2017-01-01

    The SPIRE Fourier Transform Spectrometer on-board the Herschel Space Observatory had two standard spectral resolution modes for science observations: high resolution (HR) and low resolution (LR), which could also be performed in sequence (H+LR). A comparison of the HR and LR resolution spectra taken in this sequential mode revealed a systematic discrepancy in the continuum level. Analysing the data at different stages during standard pipeline processing demonstrates that the telescope and instrument emission affect HR and H+LR observations in a systematically different way. The origin of this difference is found to lie in the variation of both the telescope and instrument response functions, while it is triggered by fast variation of the instrument temperatures. As it is not possible to trace the evolution of the response functions using housekeeping data from the instrument subsystems, the calibration cannot be corrected analytically. Therefore, an empirical correction for LR spectra has been developed, which removes the systematic noise introduced by the variation of the response functions.

  14. High Resolution CO Observations of Massive Star Forming Regions

    CERN Document Server

    Klaassen, P D; Keto, E R; Zhang, Q; Galván-Madrid, R; Liu, H-Y B

    2011-01-01

    Context. To further understand the processes involved in the formation of massive stars, we have undertaken a study of the gas dynamics surrounding three massive star forming regions. By observing the large scale structures at high resolution, we are able to determine properties such as driving source, and spatially resolve the bulk dynamical properties of the gas such as infall and outflow. Aims. With high resolution observations, we are able to determine which of the cores in a cluster forming massive stars is responsible for the large scale structures. Methods. We present CO observations of three massive star forming regions with known HII regions and show how the CO traces both infall and outflow. By combining data taken in two SMA configurations with JCMT observations, we are able to see large scale structures at high resolution. Results. We find large (0.26-0.40 pc), massive (2-3 M_sun) and energetic (13-17 \\times 10^44 erg) outflows emanating from the edges of two HII regions suggesting they are being ...

  15. First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations Angular Power Spectrum

    CERN Document Server

    Hinshaw, G; Verde, L; Hill, R S; Meyer, S S; Barnes, C; Bennett, C L; Halpern, M; Jarosik, N C; Kogut, A J; Komatsu, E; Limon, M; Page, L; Tucker, G S; Weiland, J; Wollack, E; Wright, E L

    2003-01-01

    We present the angular power spectrum derived from the first-year Wilkinson Microwave Anisotropy Probe (WMAP) sky maps. We study a variety of power spectrum estimation methods and data combinations and demonstrate that the results are robust. The data are modestly contaminated by diffuse Galactic foreground emission, but we show that a simple Galactic template model is sufficient to remove the signal. Point sources produce a modest contamination in the low frequency data. After masking ~700 known bright sources from the maps, we estimate residual sources contribute ~3500 uK^2 at 41 GHz, and ~130 uK^2 at 94 GHz, to the power spectrum l*(l+1)*C_l/(2*pi) at l=1000. Systematic errors are negligible compared to the (modest) level of foreground emission. Our best estimate of the power spectrum is derived from 28 cross-power spectra of statistically independent channels. The final spectrum is essentially independent of the noise properties of an individual radiometer. The resulting spectrum provides a definitive mea...

  16. Providing stringent star formation rate limits of z$\\sim$2 QSO host galaxies at high angular resolution

    CERN Document Server

    Vayner, Andrey; Do, Tuan; Larkin, James E; Armus, Lee; Gallagher, Sarah C

    2014-01-01

    We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z=2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini-North Observatories using OSIRIS and NIFS coupled with the LGS-AO systems. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z=2.15. We demonstrate that the combination of AO and IFS provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a PSF from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy. We detect H$\\alpha$ and [NII] for two sources, SDSS J1029+6510 and SDSS J0925+06 that have both star formation and extended narrow-line emission. Assuming that the majority of narrow-line H$\\alpha$ is from star formation, we inf...

  17. Observational semantics of the Prolog Resolution Box Model

    CERN Document Server

    Deransart, Pierre; Ferrand, Gérard

    2007-01-01

    This paper specifies an observational semantics and gives an original presentation of the Byrd box model. The approach accounts for the semantics of Prolog tracers independently of a particular Prolog implementation. Prolog traces are, in general, considered as rather obscure and difficult to use. The proposed formal presentation of its trace constitutes a simple and pedagogical approach for teaching Prolog or for implementing Prolog tracers. It is a form of declarative specification for the tracers. The trace model introduced here is only one example to illustrate general problems relating to tracers and observing processes. Observing processes know, from observed processes, only their traces. The issue is then to be able to reconstitute, by the sole analysis of the trace, part of the behaviour of the observed process, and if possible, without any loss of information. As a matter of fact, our approach highlights qualities of the Prolog resolution box model which made its success, but also its insufficiencies...

  18. On high time-range resolution observations of PMSE: Statistical characteristics

    Science.gov (United States)

    Sommer, Svenja; Chau, Jorge L.; Schult, Carsten

    2016-06-01

    We present observations of polar mesospheric summer echoes (PMSE) with an unprecedented temporal sampling of 2 ms and range resolution down to 75 m. On these time and spatial scales, PMSE exhibit features, like correlation in time and range, that have not been described before. To characterize our high resolution observations, we provide a 4-D statistical model, based on random processes. In this way we can distinguish between geophysical and instrumental effects on our measurements. In our simulations, PMSE is statistically characterized in frequency, angular space, and inverse altitude. With this model, we are able to reproduce our observations on a statistical basis and estimate the intrinsic spectral width of PMSE. For chosen data sets, such values range between 0.5 Hz and 4 Hz (1.4 ms-1 to 11.2 ms-1). Furthermore, we show that apparent oscillations in time and an apparent high speed motion of the mean scattering center are just representations of the random nature of PMSE measurements on short time scales.

  19. High resolution solar observations from first principles to applications

    Science.gov (United States)

    Verdoni, Angelo P.

    2009-10-01

    The expression "high-resolution observations" in Solar Physics refers to the spatial, temporal and spectral domains in their entirety. High-resolution observations of solar fine structure are a necessity to answer many of the intriguing questions related to solar activity. However, a researcher building instruments for high-resolution observations has to cope with the fact that these three domains often have diametrically opposed boundary conditions. Many factors have to be considered in the design of a successful instrument. Modern post-focus instruments are more closely linked with the solar telescopes that they serve than in past. In principle, the quest for high-resolution observations already starts with the selection of the observatory site. The site survey of the Advanced Technology Solar Telescope (ATST) under the stewardship of the National Solar Observatory (NSO) has identified Big Bear Solar Observatory (BBSO) as one of the best sites for solar observations. In a first step, the seeing characteristics at BBSO based on the data collected for the ATST site survey are described. The analysis will aid in the scheduling of high-resolution observations at BBSO as well as provide useful information concerning the design and implementation of a thermal control system for the New Solar Telescope (NST). NST is an off-axis open-structure Gregorian-style telescope with a 1.6 m aperture. NST will be housed in a newly constructed 5/8-sphere ventilated dome. With optics exposed to the surrounding air, NST's open-structure design makes it particularly vulnerable to the effects of enclosure-related seeing. In an effort to mitigate these effects, the initial design of a thermal control system for the NST dome is presented. The goal is to remediate thermal related seeing effects present within the dome interior. The THermal Control System (THCS) is an essential component for the open-telescope design of NST to work. Following these tasks, a calibration routine for the

  20. A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors

    CERN Document Server

    Caballero-Nieves, Saida M; Gies, Douglas R; Wallace, Debra J; DeGioia-Eastwood, Katherine; Herrero, Artemio; Jao, Wei-Chun; Mason, Brian D; Massey, Philip; Moffat, Anthony F J; Walborn, Nolan R

    2013-01-01

    We present results of a high angular resolution survey of massive OB stars in the Cygnus OB2 association that we conducted with the Fine Guidance Sensor 1R (FGS1r) on the Hubble Space Telescope. FGS1r is able to resolve binary systems with a magnitude difference delta-V 60%. One of the new discoveries is a companion to the hypergiant star MT 304 = Cyg OB2-12, and future measurements of orbital motion should provide mass estimates for this very luminous star.

  1. High-resolution spectropolarimetric observations of hot subdwarfs

    CERN Document Server

    Petit, P; Bagnulo, S; Charpinet, S; Wade, G A; Green, E M

    2011-01-01

    We report on high-resolution spectropolarimetric observations of the hot subdwarf stars HD 76431 and Feige 66, using the ESPaDOnS echelle spectropolarimeter at CFHT. We compute cross-correlation Stokes I and V line profiles to enhance the signal-to-noise ratio. We then average all available cross-correlation profiles of each star to further decrease the noise level. Although both targets were previously reported to host kilo-gauss magnetic fields, we do not derive any evidence of large-scale photospheric fields from our sets of observations, in spite of tight error bars on the longitudinal field of the order of 60 gauss for HD 76431 and 200 gauss for Feige 66. A new analysis of FORS1 observations of HD 76431, which provided the basis for the original claim of field detection, confirms the absence of any detectable Zeeman signature, with an error bar of about 100 gauss on the longitudinal magnetic field.

  2. Physical Version of Singularity Resolution in the Observable Universe

    CERN Document Server

    Song, Daegene

    2016-01-01

    Based on the equivalence of the two different types of measurement protocols and the asymmetry between the Schr\\"odinger and Heisenberg pictures, it has been previously proposed that negative sea fills the universe as a nondeterministic computation - a time-reversal process of the irreversible computations presented since the big bang. The goal of this paper is to extend the proposed subjective universe model, i.e., the universe as a quantum measurement: Motivated by the relationship between quantum theory and classical probability theory with continuity, it is argued that the frame of reference of the observer may be identified with classical probability theory where its choice, along with big bang singularity, should correspond to the quantum observable. That is, the physical version of singularity resolution corresponds to the case, where big bang singularity is equivalent to the continuity of the negative sea, or aether, filling the universe as a frame of reference of the observer. Moreover, based on the ...

  3. Providing Stringent Star Formation Rate Limits of z ˜ 2 QSO Host Galaxies at High Angular Resolution

    Science.gov (United States)

    Vayner, Andrey; Wright, Shelley A.; Do, Tuan; Larkin, James E.; Armus, Lee; Gallagher, S. C.

    2016-04-01

    We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z ˜ 2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini North Observatories, using OSIRIS and NIFS coupled with the LGS-AO systems, respectively. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z = 2.2. We demonstrate that the combination of AO and IFSs provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a point-spread function (PSF) from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy emission at a separation of ˜0.″2 (˜1.4 kpc). We detect Hα narrow-line emission for two sources, SDSS J1029+6510 (zHα = 2.182) and SDSS J0925+0655 (zHα = 2.197), that have evidence for both star formation and extended narrow-line emission. Assuming that the majority of narrow-line Hα emission is from star formation, we infer a star formation rate (SFR) for SDSS J1029+6510 of 78.4 M⊙ yr-1 originating from a compact region that is kinematically offset by 290-350 km s-1. For SDSS J0925+0655 we infer a SFR of 29 M⊙ yr-1 distributed over three clumps that are spatially offset by ˜7 kpc. The null detections on three of the QSOs are used to infer surface brightness limits and we find that at 1.4 kpc from the QSO the un-reddened star formation limit is ≲0.3 M⊙ yr-1 kpc-2. If we assume typical extinction values for z = 2 type-1 QSOs, the dereddened SFR for our null detections would be ≲0.6 M⊙ yr-1 kpc-2. These IFS observations indicate that while the central black hole is accreting mass at 10%-40% of the Eddington rate, if star formation is present in the host (1.4-20 kpc) it would have to occur diffusely with significant

  4. Quantitative observation of tracer transport with high-resolution PET

    Science.gov (United States)

    Kulenkampff, Johannes; Gruendig, Marion; Zakhnini, Abdelhamid; Lippmann-Pipke, Johanna

    2016-04-01

    Transport processes in natural porous media are typically heterogeneous over various scales. This heterogeneity is caused by the complexity of pore geometry and molecular processes. Heterogeneous processes, like diffusive transport, conservative advective transport, mixing and reactive transport, can be observed and quantified with quantitative tomography of tracer transport patterns. Positron Emission Tomography (PET) is by far the most sensitive method and perfectly selective for positron-emitting radiotracers, therefore it is suited as reference method for spatiotemporal tracer transport observations. The number of such PET-applications is steadily increasing. However, many applications are afflicted by the low spatial resolution (3 - 5 mm) of the clinical scanners from cooperating nuclear medical departments. This resolution is low in relation to typical sample dimensions of 10 cm, which are restricted by the mass attenuation of the material. In contrast, our GeoPET-method applies a high-resolution scanner with a resolution of 1 mm, which is the physical limit of the method and which is more appropriate for samples of the size of soil columns or drill cores. This higher resolution is achieved at the cost of a more elaborate image reconstruction procedure, especially considering the effects of Compton scatter. The result of the quantitative image reconstruction procedure is a suite of frames of the quantitative tracer distribution with adjustable frame rates from minutes to months. The voxel size has to be considered as reference volume of the tracer concentration. This continuous variable includes contributions from structures far below the spatial resolution, as far as a detection threshold, in the pico-molar range, is exceeded. Examples from a period of almost 10 years (Kulenkampff et al. 2008a, Kulenkampff et al. 2008b) of development and application of quantitative GeoPET-process tomography are shown. These examples include different transport processes

  5. Continued Development of Small-Pixel CZT and CdTe Detectors for Future High-Angular-Resolution Hard X-ray Missions

    Science.gov (United States)

    Krawczynski, Henric

    The Nuclear Spectroscopic Telescope Array (NuSTAR) Small Explorer Mission was launched in June 2012 and has demonstrated the technical feasibility and high scientific impact of hard X-ray astronomy. We propose to continue our current R&D program to develop finely pixelated semiconductor detectors and the associated readout electronics for the focal plane of a NuSTAR follow-up mission. The detector-ASIC (Application Specific Integrated Circuit) package will be ideally matched to the new generation of low-cost, low-mass X-ray mirrors which achieve an order of magnitude better angular resolution than the NuSTAR mirrors. As part of this program, the Washington University group will optimize the contacts of 2x2 cm^2 footprint Cadmium Zinc Telluride (CZT) and Cadmium Telluride (CdTe) detectors contacted with 100x116 hexagonal pixels at a next-neighbor pitch of 200 microns. The Brookhaven National Laboratory group will design, fabricate, and test the next generation of the HEXID ASIC matched to the new X-ray mirrors and the detectors, providing a low-power 100x116 channel ASIC with extremely low readout noise (i.e. with a root mean square noise of 13 electrons). The detectors will be tested with radioactive sources and in the focal plane of high-angular-resolution X-ray mirrors at the X-ray beam facilities at the Goddard and Marshall Space Flight Centers.

  6. PROVIDING STRINGENT STAR FORMATION RATE LIMITS OF z ∼ 2 QSO HOST GALAXIES AT HIGH ANGULAR RESOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Vayner, Andrey; Wright, Shelley A. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4 (Canada); Do, Tuan [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4 (Canada); Larkin, James E. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Armus, Lee [Spitzer Science Center, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Gallagher, S. C. [Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7 (Canada)

    2016-04-10

    We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z ∼ 2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini North Observatories, using OSIRIS and NIFS coupled with the LGS-AO systems, respectively. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z = 2.2. We demonstrate that the combination of AO and IFSs provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a point-spread function (PSF) from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy emission at a separation of ∼0.″2 (∼1.4 kpc). We detect Hα narrow-line emission for two sources, SDSS J1029+6510 (z{sub Hα} = 2.182) and SDSS J0925+0655 (z{sub Hα} = 2.197), that have evidence for both star formation and extended narrow-line emission. Assuming that the majority of narrow-line Hα emission is from star formation, we infer a star formation rate (SFR) for SDSS J1029+6510 of 78.4 M{sub ⊙} yr{sup −1} originating from a compact region that is kinematically offset by 290–350 km s{sup −1}. For SDSS J0925+0655 we infer a SFR of 29 M{sub ⊙} yr{sup −1} distributed over three clumps that are spatially offset by ∼7 kpc. The null detections on three of the QSOs are used to infer surface brightness limits and we find that at 1.4 kpc from the QSO the un-reddened star formation limit is ≲0.3 M{sub ⊙} yr{sup −1} kpc{sup −2}. If we assume typical extinction values for z = 2 type-1 QSOs, the dereddened SFR for our null detections would be ≲0.6 M{sub ⊙} yr{sup −1} kpc{sup −2}. These IFS observations indicate that while the central black hole is accreting mass at 10%–40% of the Eddington rate, if

  7. Applications of High-Resolution Observations at Millimeter Wavelengths

    Science.gov (United States)

    Rosenfeld, Katherine

    Interferometric observations at millimeter wavelengths provide a precious, detailed view of certain astrophysical objects. This thesis is composed of studies that both rely on and enable this technique to study the structure of planet-forming disks and soon image the closest regions around super-massive black holes. Young stars form out of a cloud of gas and dust that, before its eventual dissipation, flattens to a disk. However the disk population is diverse and recent high-resolution images have revealed a wide variety of interesting features. To understand these observations we use detailed radiative transfer models to motivate various physical scenarios. First we identify a set of traits in the disk around V4046 Sgr that marks the coupled progression of the gas and dust distributions in the presence of at least one embedded companion. Next, we investigate how the vertical temperature structure of a disk can be spatially resolved and apply our framework to observations of the disk around HD163296. Lastly, we show how large-scale radial flows of gas may be observable and question how this phenomenon might be distinguished from other scenarios such as warps or outflows. The last chapter summarizes the APHIDS project which changes the sampling rate of data taken at the SMA so that it may be used for VLBI campaigns.

  8. High Resolution Observations of the CMB Power Spectrum with ACBAR

    CERN Document Server

    Kuo, C L; Bock, J J; Cantalupo, C M; Daub, M D; Goldstein, J; Holzapfel, W L; Lange, A E; Lueker, M; Newcomb, M; Peterson, J B; Ruhl, J; Runyan, M C; Torbet, E

    2004-01-01

    We report the first measurements of anisotropy in the cosmic microwave background (CMB) radiation with the Arcminute Cosmology Bolometer Array Receiver (ACBAR). The instrument was installed on the 2.1m Viper telescope at the South Pole in January 2001; the data presented here are the product of observations up to and including July 2002. The two deep fields presented here, have had offsets removed by subtracting lead and trail observations and cover approximately 24 deg^2 of sky selected for low dust contrast. These results represent the highest signal to noise observations of CMB anisotropy to date; in the deepest 150GHz band map, we reached an RMS of 8.0\\mu K per 5' beam. The 3 degree extent of the maps, and small beamsize of the experiment allow the measurement of the CMB anisotropy power spectrum over the range \\ell = 150-3000 with resolution of \\Delta \\ell=150. The contributions of galactic dust and radio sources to the observed anisotropy are negligible and are removed in the analysis. The resulting pow...

  9. Rapid PPP ambiguity resolution using GPS+GLONASS observations

    Science.gov (United States)

    Liu, Yanyan; Ye, Shirong; Song, Weiwei; Lou, Yidong; Gu, Shengfeng

    2017-04-01

    Integer ambiguity resolution (IAR) in precise point positioning (PPP) using GPS observations has been well studied. The main challenge remaining is that the first ambiguity fixing takes about 30 min. This paper presents improvements made using GPS+GLONASS observations, especially improvements in the initial fixing time and correct fixing rate compared with GPS-only solutions. As a result of the frequency division multiple access strategy of GLONASS, there are two obstacles to GLONASS PPP-IAR: first and most importantly, there is distinct code inter-frequency bias (IFB) between satellites, and second, simultaneously observed satellites have different wavelengths. To overcome the problem resulting from GLONASS code IFB, we used a network of homogeneous receivers for GLONASS wide-lane fractional cycle bias (FCB) estimation and wide-lane ambiguity resolution. The integer satellite clock of the GPS and GLONASS was then estimated with the wide-lane FCB products. The effect of the different wavelengths on FCB estimation and PPP-IAR is discussed in detail. We used a 21-day data set of 67 stations, where data from 26 stations were processed to generate satellite wide-lane FCBs and integer clocks and the other 41 stations were selected as users to perform PPP-IAR. We found that GLONASS FCB estimates are qualitatively similar to GPS FCB estimates. Generally, 98.8% of a posteriori residuals of wide-lane ambiguities are within ± 0.25 cycles for GPS, and 96.6% for GLONASS. Meanwhile, 94.5 and 94.4% of narrow-lane residuals are within 0.1 cycles for GPS and GLONASS, respectively. For a critical value of 2.0, the correct fixing rate for kinematic PPP is only 75.2% for GPS alone and as large as 98.8% for GPS+GLONASS. The fixing percentage for GPS alone is only 11.70 and 46.80% within 5 and 10 min, respectively, and improves to 73.71 and 95.83% when adding GLONASS. Adding GLONASS thus improves the fixing percentage significantly for a short time span. We also used global ionosphere

  10. High-Resolution Observations of a Binary Black Hole Candidate

    Science.gov (United States)

    Tsai, Chao-Wei; Phillips, Chris; Norris, Ray; Jarrett, Thomas; Emonts, Bjorn; Cluver, Michelle; Eisenhardt, Peter; Stern, Daniel; Assef, Roberto

    2012-10-01

    We propose a 12-hour 2.3 GHz continuum Long Baseline Array (LBA) observation of WISE J2332-5056, a newly discovered supermassive black hole (SMBH) merger candidate that is located in the nearby universe (z = 0.3447). Our recently acquired 9 GHz ATCA map shows unusual radio morphology: a one-sided, smaller (and likely younger) FR-I jet perpendicular to a larger, Doppler-boosted FR-II jet. Follow-up Gemini-S/GMOS spectroscopy of this WISE-selected radio galaxy reveals broad emission lines blue-shifted by > 3,500 km/s with respect to the narrow lines and host galaxy, hallmarks of a dual AGN system. Combined, the optical spectroscopy and radio morphology of this object are strongly suggestive of a black hole merger system. Even in the local universe these systems are extremely difficult to identify; yet the process of supermassive blackhole growth is vital toward understanding galaxy evolution from the early to the current universe. Moreover, nearby merging SMBHs may serve as outstanding targets for gravitational wave studies. The proposed high resolution LBA map, reaching 50 pc resolution at the source redshift will allow us to investigate the SMBH merger scenario hypothesis.

  11. Angular Momentum Transport in Accretion Disks

    DEFF Research Database (Denmark)

    E. Pessah, Martin; Chan, Chi-kwan; Psaltis, Dimitrios;

    2007-01-01

    if the resolution were set equal to the natural dissipation scale in astrophysical disks. We conclude that, in order for MRI-driven turbulent angular momentum transport to be able to account for the large value of the effective alpha viscosity inferred observationally, the disk must be threaded by a significant...

  12. A Photoisomerizing Rhodopsin Mimic Observed at Atomic Resolution.

    Science.gov (United States)

    Nosrati, Meisam; Berbasova, Tetyana; Vasileiou, Chrysoula; Borhan, Babak; Geiger, James H

    2016-07-20

    The members of the rhodopsin family of proteins are involved in many essential light-dependent processes in biology. Specific photoisomerization of the protein-bound retinylidene PSB at a specified wavelength range of light is at the heart of all of these systems. Nonetheless, it has been difficult to reproduce in an engineered system. We have developed rhodopsin mimics, using intracellular lipid binding protein family members as scaffolds, to study fundamental aspects of protein/chromophore interactions. Herein we describe a system that specifically isomerizes the retinylidene protonated Schiff base both thermally and photochemically. This isomerization has been characterized at atomic resolution by quantitatively interconverting the isomers in the crystal both thermally and photochemically. This event is accompanied by a large pKa change of the imine similar to the pKa changes observed in bacteriorhodopsin and visual opsins during isomerization.

  13. Observation of long-range, near-side angular correlations in pPb collisions at the LHC

    Science.gov (United States)

    Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Aguilo, E.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Pernicka, M.; Rabady, D.; Rahbaran, B.; Rohringer, C.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Bansal, M.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Luyckx, S.; Mucibello, L.; Ochesanu, S.; Roland, B.; Rougny, R.; Selvaggi, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Gonzalez Suarez, R.; Kalogeropoulos, A.; Maes, M.; Olbrechts, A.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Clerbaux, B.; De Lentdecker, G.; Dero, V.; Gay, A. P. R.; Hreus, T.; Léonard, A.; Marage, P. E.; Mohammadi, A.; Reis, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Adler, V.; Beernaert, K.; Cimmino, A.; Costantini, S.; Garcia, G.; Grunewald, M.; Klein, B.; Lellouch, J.; Marinov, A.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Sigamani, M.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Walsh, S.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Bruno, G.; Castello, R.; Ceard, L.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Lemaitre, V.; Liao, J.; Militaru, O.; Nuttens, C.; Pagano, D.; Pin, A.; Piotrzkowski, K.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Alves, G. A.; Correa Martins, M.; Martins, T.; Pol, M. E.; Souza, M. H. G.; Aldá, W. L.; Carvalho, W.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Malbouisson, H.; Malek, M.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santoro, A.; Soares Jorge, L.; Sznajder, A.; Vilela Pereira, A.; Anjos, T. S.; Bernardes, C. A.; Dias, F. A.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Lagana, C.; Marinho, F.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Genchev, V.; Iaydjiev, P.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Tcholakov, V.; Trayanov, R.; Vutova, M.; Dimitrov, A.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Jiang, C. H.; Liang, D.; Liang, S.; Meng, X.; Tao, J.; Wang, J.; Wang, X.; Wang, Z.; Xiao, H.; Xu, M.; Zang, J.; Zhang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Guo, Y.; Li, W.; Liu, S.; Mao, Y.; Qian, S. J.; Teng, H.; Wang, D.; Zhang, L.; Zou, W.; Avila, C.; Carrillo Montoya, C. A.; Gomez, J. P.; Gomez Moreno, B.; Osorio Oliveros, A. F.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Plestina, R.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Duric, S.; Kadija, K.; Luetic, J.; Mekterovic, D.; Morovic, S.; Attikis, A.; Galanti, M.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Finger, M.; Finger, M.; Assran, Y.; Elgammal, S.; Ellithi Kamel, A.; Mahmoud, M. A.; Mahrous, A.; Radi, A.; Kadastik, M.; Müntel, M.; Murumaa, M.; Raidal, M.; Rebane, L.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Heikkinen, A.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Ungaro, D.; Wendland, L.; Banzuzi, K.; Karjalainen, A.; Korpela, A.; Tuuva, T.; Besancon, M.; Choudhury, S.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Millischer, L.; Nayak, A.; Rander, J.; Rosowsky, A.; Titov, M.; Baffioni, S.; Beaudette, F.; Benhabib, L.; Bianchini, L.; Bluj, M.; Busson, P.; Charlot, C.; Daci, N.; Dahms, T.; Dalchenko, M.; Dobrzynski, L.; Florent, A.; Granier de Cassagnac, R.; Haguenauer, M.; Miné, P.; Mironov, C.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Paganini, P.; Sabes, D.; Salerno, R.; Sirois, Y.; Veelken, C.; Zabi, A.; Agram, J.-L.; Andrea, J.; Bloch, D.; Bodin, D.; Brom, J.-M.; Cardaci, M.; Chabert, E. C.; Collard, C.; Conte, E.; Drouhin, F.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Juillot, P.; Le Bihan, A.-C.; Van Hove, P.; Fassi, F.; Mercier, D.; Beauceron, S.; Beaupere, N.; Bondu, O.; Boudoul, G.; Brochet, S.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Sgandurra, L.; Sordini, V.; Tschudi, Y.; Verdier, P.; Viret, S.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Calpas, B.; Edelhoff, M.; Feld, L.; Heracleous, N.; Hindrichs, O.

    2013-01-01

    Results on two-particle angular correlations for charged particles emitted in pPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV are presented. The analysis uses two million collisions collected with the CMS detector at the LHC. The correlations are studied over a broad range of pseudorapidity, η, and full azimuth, ϕ, as a function of charged particle multiplicity and particle transverse momentum, pT. In high-multiplicity events, a long-range (2 < | Δη | < 4), near-side (Δϕ ≈ 0) structure emerges in the two-particle Δη-Δϕ correlation functions. This is the first observation of such correlations in proton-nucleus collisions, resembling the ridge-like correlations seen in high-multiplicity pp collisions at √{ s} = 7 TeV and in AA collisions over a broad range of center-of-mass energies. The correlation strength exhibits a pronounced maximum in the range of pT = 1- 1.5 GeV / c and an approximately linear increase with charged particle multiplicity for high-multiplicity events. These observations are qualitatively similar to those in pp collisions when selecting the same observed particle multiplicity, while the overall strength of the correlations is significantly larger in pPb collisions.

  14. Improved SOT (Hinode mission) high resolution solar imaging observations

    CERN Document Server

    Goodarzi, Hadis; Adjabshirizadeh, Ali

    2015-01-01

    We consider the best today available observations of the Sun free of turbulent Earth atmospheric effects, taken with the Solar Optical Telescope (SOT) onboard the Hinode spacecraft. Both the instrumental smearing and the observed stray light are analyzed in order to improve the resolution. The Point Spread Function (PSF) corresponding to the blue continuum Broadband Filter Imager (BFI) near 450 nm is deduced by analyzing i/ the limb of the Sun and ii/ images taken during the transit of the planet Venus in 2012. A combination of Gaussian and Lorentzian functions is selected to construct a PSF in order to remove both smearing due to the instrumental diffraction effects (PSF core) and the large-angle stray light due to the spiders and central obscuration (wings of the PSF) that are responsible for the parasitic stray light. A Max-likelihood deconvolution procedure based on an optimum number of iterations is discussed. It is applied to several solar field images, including the granulation near the limb. The norma...

  15. Probing Gas and Dust around B[e] Stars at the Highest Angular Resolution: A Decade of Interferometric Studies

    Science.gov (United States)

    Meilland, A.

    2017-02-01

    Long-baseline interferometry is the one and only technique offering the sub-milliarcsecond resolution needed to spatially resolve the close environment of stars. Since the construction of modern facilities such as the Very Large Telescope Interferometer (VLTI) in Chile, and the Center for High Resolution Array (CHARA) in California, it became a key technique to probe massive stars and their often complex circumstellar environments. The more recent generation of instruments even combines the power of interferometry and spectroscopy allowing to put more constraints on chemical, physical, and dynamical properties of circumstellar gas and dust. Here I briefly present the technique and the current generation of instruments, I review the main results obtained in the last decade on B[e] stars, and, I present the upcoming second generation of instruments at VLTI and the current plan to upgrade CHARA.

  16. Martian surface microtexture from orbital CRISM multi-angular observations: A new perspective for the characterization of the geological processes

    Science.gov (United States)

    Fernando, J.; Schmidt, F.; Douté, S.

    2016-09-01

    volume scattering, are sensitive to the grain morphology and internal structure. The surface material photometric parameters estimated from the CRISM multi-angular observations at 750 nm are compared to the geological units in order to better characterize the geological processes. The photometric results show a high diversity of surface scattering behaviors (from a broad and backward scattering behavior to a narrow and forward scattering behavior) that suggests a high diversity of surface microtexture. A narrow forward scattering behavior has been detected for the first time from martian orbital data and observed in peculiar regions dominated by salt-bearing and clay-bearing materials. Hence the martian photometric results suggest that Mars experimented varied geological processes still preserved in the material microtexture. This study also demonstrates that these properties provide complementary information to mineralogy and geomorphology to better constrain the geological processes.

  17. OBSERVING CASCADES OF SOLAR BULLETS AT HIGH RESOLUTION. II

    Energy Technology Data Exchange (ETDEWEB)

    Scullion, E.; Engvold, O.; Lin, Y.; Voort, L. Rouppe van der, E-mail: scullie@tcd.ie [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway)

    2015-12-01

    High resolution observations from the Swedish 1-m Solar Telescope revealed bright, discrete, blob-like structures (which we refer to as solar bullets) in the Hα 656.28 nm line core that appear to propagate laterally across the solar atmosphere as clusters in active regions (ARs). These small-scale structures appear to be field aligned and many bullets become triggered simultaneously and traverse collectively as a cluster. Here, we conduct a follow-up study on these rapidly evolving structures with coincident observations from the Solar Dynamics Observatory/Atmospheric Imaging Assembly. With the co-aligned data sets, we reveal (a) an evolving multithermal structure in the bullet cluster ranging from chromospheric to at least transition region temperatures, (b) evidence for cascade-like behavior and corresponding bidirectional motions in bullets within the cluster, which indicate that there is a common source of the initial instability leading to bullet formation, and (c) a direct relationship between co-incident bullet velocities observed in Hα and He ii 30.4 nm and an inverse relationship with respect to bullet intensity in these channels. We find evidence supporting that bullets are typically composed of a cooler, higher density core detectable in Hα with a less dense, hotter, and fainter co-moving outer sheath. Bullets unequivocally demonstrate the finely structured nature of the AR corona. We have no clear evidence for bullets being associated with locally heated (or cooled), fast flowing plasma. Fast MHD pulses (such as solitons) could best describe the dynamic properties of bullets whereas the presence of a multithermal structure is new.

  18. TES/Aura L1B Spectra Special Observation Low Resolution V004

    Data.gov (United States)

    National Aeronautics and Space Administration — The L1B Low Resolution granule consists of radiometrically calibrated spectra & associated NESR, observed at 0.1 cm-1 resolution for a Special Observation &...

  19. TES/Aura L1B Spectra Special Observation Low Resolution V003

    Data.gov (United States)

    National Aeronautics and Space Administration — The L1B Low Resolution granule consists of radiometrically calibrated spectra & associated NESR, observed at 0.1 cm-1 resolution for a Special Observation &...

  20. TES/Aura L1B Spectra Special Observation Low Resolution V005

    Data.gov (United States)

    National Aeronautics and Space Administration — The L1B Low Resolution granule consists of radiometrically calibrated spectra & associated NESR, observed at 0.1 cm-1 resolution for a Special Observation &...

  1. TES/Aura L1B Spectra Special Observation High Resolution V004

    Data.gov (United States)

    National Aeronautics and Space Administration — A L1B High Resolution granule consists of radiometrically calibrated spectra & associated NESR, observed at 0.025 cm-1 resolution for a Special Observation &...

  2. VLBI observations of single stars, spatial resolution and astrometry

    Science.gov (United States)

    Pestalozzi, M.; Benz, A. O.; Conway, J. E.; Gudel, M.; Smith, K.

    VLBI studies can both spatially resolve single dMe stars and measure their positions at submilliarcsecond accuracy. The spatial resolution gives the brightness temperature and allows us to draw co nclusions about the nature of the emitting processes. In particular it is possib le to distinguish between thermal or non-thermal emission. The position accuracy gives better knowledge about the astrometric properties (like proper motion and parallax) especially for nearby stars. In this contribution recent results of c ontinuum VLBI observations towards two dMe stars (YZ CMi and AD Leo) at 8.4 GHz are presented. For YZ CMi an estimate of the size of the coronal emission is giv en (0.98 mas in diameter or 0.7 ±0.3 Rstar above the photosphere where Rstar refers to the photospheric radius). For AD Leo an upper limit is gi ven, i.e. the emitting region is shown to be Pestalozzi et al. 2000 ).

  3. High spatial and spectral resolution 10-micron observations of Jupiter

    Science.gov (United States)

    Tokunaga, A. T.; Ridgway, S. T.; Knacke, R. F.

    1980-01-01

    Ten-micrometer spectra of the North Tropical Zone, North Equatorial Belt, and Great Red Spot at a spectral resolution of 1.1/cm are compared to synthetic spectra. These ground-based spectra were obtained simultaneously with the Voyager 1 encounter with Jupiter in March, 1979. The NH3 vertical distribution is found to decrease with altitude significantly faster than the saturated vapor pressure curve and is different for the three observed regions. Spatial variability in the NH3 mixing ratio could be caused by changes in the amount of NH3 condensation or in the degree of the NH3 photolysis. The C2H6 emission at 12 microns has approximately the same strength at the North Tropical Zone and North Equatorial Belt, but it is 30% weaker at the Great Red Spot. A cooler temperature inversion or a smaller abundance of C2H6 could explain the lower C2H6 emission over the Great Red Spot.

  4. Observation of Long-Range, Near-Side Angular Correlations in Proton-Proton Collisions at the LHC

    CERN Document Server

    Khachatryan, Vardan; Tumasyan, Armen; Adam, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hammer, Josef; Haensel, Stephan; Hartl, Christian; Hoch, Michael; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kasieczka, Gregor; Kiesenhofer, Wolfgang; Krammer, Manfred; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Teischinger, Florian; Waltenberger, Wolfgang; Walzel, Gerhard; Widl, Edmund; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Benucci, Leonardo; Ceard, Ludivine; De Wolf, Eddi A.; Janssen, Xavier; Maes, Thomas; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Adler, Volker; Beauceron, Stephanie; Blyweert, Stijn; D'Hondt, Jorgen; Devroede, Olivier; Kalogeropoulos, Alexis; Maes, Joris; Maes, Michael; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Villella, Ilaria; Chabert, Eric Christian; Charaf, Otman; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hammad, Gregory Habib; Hreus, Tomas; Marage, Pierre Edouard; Vander Velde, Catherine; Vanlaer, Pascal; Wickens, John; Costantini, Silvia; Grunewald, Martin; Klein, Benjamin; Marinov, Andrey; Ryckbosch, Dirk; Thyssen, Filip; Tytgat, Michael; Vanelderen, Lukas; Verwilligen, Piet; Walsh, Sinead; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Caudron, Julien; De Favereau De Jeneret, Jerome; Delaere, Christophe; Demin, Pavel; Favart, Denis; Giammanco, Andrea; Grégoire, Ghislain; Hollar, Jonathan; Lemaitre, Vincent; Militaru, Otilia; Ovyn, Severine; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Quertenmont, Loic; Schul, Nicolas; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Alves, Gilvan; De Jesus Damiao, Dilson; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Carvalho, Wagner; Da Costa, Eliza Melo; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Mundim, Luiz; Nogima, Helio; Oguri, Vitor; Otalora Goicochea, Juan Martin; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Silva Do Amaral, Sheila Mara; Sznajder, Andre; Torres Da Silva De Araujo, Felipe; De Almeida Dias, Flavia; Ferreira Dias, Marco Andre; Tomei, Thiago; De Moraes Gregores, Eduardo; Da Cunha Marinho, Franciole; Novaes, Sergio F.; Padula, Sandra; Darmenov, Nikolay; Dimitrov, Lubomir; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vankov, Ivan; Dyulendarova, Milena; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Marinova, Evelina; Mateev, Matey; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Wang, Jian; Wang, Jian; Wang, Xianyou; Wang, Zheng; Yang, Min; Zang, Jingjing; Zhang, Zhen; Ban, Yong; Guo, Shuang; Hu, Zhen; Li, Wenbo; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Zhu, Bo; Cabrera, Andrés; Gomez Moreno, Bernardo; Ocampo Rios, Alberto Andres; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Lelas, Karlo; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Dzelalija, Mile; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Morovic, Srecko; Attikis, Alexandros; Fereos, Reginos; Galanti, Mario; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A.; Rykaczewski, Hans; Assran, Yasser; Mahmoud, Mohammed; Hektor, Andi; Kadastik, Mario; Kannike, Kristjan; Müntel, Mait; Raidal, Martti; Rebane, Liis; Azzolini, Virginia; Eerola, Paula; Czellar, Sandor; Härkönen, Jaakko; Heikkinen, Mika Aatos; Karimäki, Veikko; Kinnunen, Ritva; Klem, Jukka; Kortelainen, Matti J.; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Korpela, Arja; Tuuva, Tuure; Sillou, Daniel; Besancon, Marc; Dejardin, Marc; Denegri, Daniel; Descamps, Julien; Fabbro, Bernard; Faure, Jean-Louis; Ferri, Federico; Ganjour, Serguei; Gentit, François-Xavier; Givernaud, Alain; Gras, Philippe; Hamel de Monchenault, Gautier; Jarry, Patrick; Locci, Elizabeth; Malcles, Julie; Marionneau, Matthieu; Millischer, Laurent; Rander, John; Rosowsky, André; Rousseau, Delphine; Titov, Maksym; Verrecchia, Patrice; Baffioni, Stephanie; Bianchini, Lorenzo; Bluj, Michal; Broutin, Clementine; Busson, Philippe

    2010-01-01

    Results on two-particle angular correlations for charged particles emitted in proton-proton collisions at center-of-mass energies of 0.9, 2.36, and 7 TeV are presented, using data collected with the CMS detector over a broad range of pseudorapidity (eta) and azimuthal angle ($\\phi$). Short-range correlations in $\\Delta\\eta$, which are studied in minimum bias events, are characterized using a simple "independent cluster" parametrization in order to quantify their strength (cluster size) and their extent in $\\eta$ (cluster decay width). Long-range azimuthal correlations are studied differentially as a function of charged particle multiplicity and particle transverse momentum using a 980 inverse nb data set at 7 TeV. In high multiplicity events, a pronounced structure emerges in the two-dimensional correlation function for particle pairs with intermediate transverse momentum of 1-3 GeV/c, 2.0 < |$\\Delta\\eta$| < 4.8 and $\\Delta\\phi \\approx 0$. This is the first observation of such a long-range, near-side fe...

  5. Observation of long-range, near-side angular correlations in pPb collisions at the LHC

    CERN Document Server

    Chatrchyan, Serguei; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Aguilo, Ernest; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Knünz, Valentin; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rabady, Dinyar; Rahbaran, Babak; Rohringer, Christine; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Waltenberger, Wolfgang; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Bansal, Monika; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Luyckx, Sten; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Olbrechts, Annik; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hreus, Tomas; Léonard, Alexandre; Marage, Pierre Edouard; Mohammadi, Abdollah; Reis, Thomas; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Adler, Volker; Beernaert, Kelly; Cimmino, Anna; Costantini, Silvia; Garcia, Guillaume; Grunewald, Martin; Klein, Benjamin; Lellouch, Jérémie; Marinov, Andrey; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Ryckbosch, Dirk; Sigamani, Michael; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Walsh, Sinead; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Castello, Roberto; Ceard, Ludivine; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Alves, Gilvan; Correa Martins Junior, Marcos; Martins, Thiago; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Aldá Júnior, Walter Luiz; Carvalho, Wagner; Custódio, Analu; Da Costa, Eliza Melo; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Malbouisson, Helena; Malek, Magdalena; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Soares Jorge, Luana; Sznajder, Andre; Vilela Pereira, Antonio; Souza Dos Anjos, Tiago; Bernardes, Cesar Augusto; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Da Cunha Marinho, Franciole; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vutova, Mariana; Dimitrov, Anton; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Meng, Xiangwei; Tao, Junquan; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xiao, Hong; Xu, Ming; Zang, Jingjing; Zhang, Zhen; Asawatangtrakuldee, Chayanit; Ban, Yong; Guo, Yifei; Li, Wenbo; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Wang, Dayong; Zhang, Linlin; Zou, Wei; Avila, Carlos; Carrillo Montoya, Camilo Andres; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Luetic, Jelena; Mekterovic, Darko; Morovic, Srecko; Attikis, Alexandros; Galanti, Mario; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Mahmoud, Mohammed; Mahrous, Ayman; Radi, Amr; Kadastik, Mario; Müntel, Mait; Murumaa, Marion; Raidal, Martti; Rebane, Liis; Tiko, Andres; Eerola, Paula; Fedi, Giacomo; Voutilainen, Mikko; Härkönen, Jaakko; Heikkinen, Mika Aatos; Karimäki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Peltola, Timo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Karjalainen, Ahti; Korpela, Arja; Tuuva, Tuure; Besancon, Marc

    2013-01-01

    Results on two-particle angular correlations for charged particles emitted in pPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV are presented. The analysis uses two million collisions collected with the CMS detector at the LHC. The correlations are studied over a broad range of pseudorapidity, eta, and full azimuth, phi, as a function of charged particle multiplicity and particle transverse momentum, pt. In high-multiplicity events, a long-range (2observation of such correlations in proton-nucleus collisions, resembling the ridge-like correlations seen in high-multiplicity pp collisions at sqrt(s) = 7 TeV and in A on A collisions over a broad range of center-of-mass energies. The correlation strength exhibits a pronounced maximum in the range of pt = 1-1.5 GeV and an approximately linear increase with charged particle...

  6. Discovery potential of xenon-based neutrinoless double beta decay experiments in light of small angular scale CMB observations

    CERN Document Server

    Gomez-Cadenas, J J; Vidal, J Muñoz; Peña-Garay, C

    2013-01-01

    The South Pole Telescope (SPT) has probed an expanded angular range of the CMB temperature power spectrum. Their recent analysis of the latest cosmological data prefers nonzero neutrino masses, mnu = 0.32+-0.11 eV. This result, if confirmed by the upcoming Planck data, has deep implications on the discovery of the nature of neutrinos. In particular, the values of the effective neutrino mass involved in neutrinoless double beta decay (bb0nu) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based bb0nu experiments, on the double grounds of their good performance and the suitability of the technology to large-mass scaling. We show that the current generation, with effective masses in the range of 100 kg and conceivable exposures in the range of 500 kg year, could already have a sizable opportunity to observe bb0nu events, and their combined discovery potential is quite large. The next generation, with an exposure in the rang...

  7. The 2008 outburst in the Young Stellar System Z CMa. III - Multi-epoch high-angular resolution images and spectra of the components in near-infrared

    CERN Document Server

    Bonnefoy, M; Dougados, C; Kospal, A; Benisty, M; Duchene, G; Bouvier, J; Garcia, P J V; Whelan, E; Antoniucci, S; Podio, L

    2016-01-01

    Z CMa is a complex pre-main sequence binary with a current separation of 100 mas, known to consist of an FU Orionis star (SE component) and an embedded Herbig Be star (NW component). Immediately when the late-2008 outburst of Z CMa was announced to the community, we initiated a high angular resolution imaging campaign with VLT/NaCo, Keck/NIRC2, VLT/SINFONI, and Keck/OSIRIS which aimed at characterizing the outburst of both components of the system in the near-infrared. We confirm that the NW star dominates the system flux in the 1.1-3.8 microns range and is responsible for the photometric outburst. We extract the first medium-resolution (R=2000-4000) near-infrared (1.1-2.4 microns) spectra of the individual components during and after the outburst. The SE component has a spectrum typical of FU Orionis objects. The NW component spectrum is characteristic of embedded outbursting protostars and EX Or objects. It displays numerous emission lines during the outburst whose intensity correlates with the system activ...

  8. Mean angular diameters, distances, and pulsation modes of the classical Cepheids FF Aquilae and T Vulpeculae. CHARA/FLUOR near-infrared interferometric observations

    Science.gov (United States)

    Gallenne, A.; Kervella, P.; Mérand, A.; McAlister, H.; ten Brummelaar, T.; Coudé du Foresto, V.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J.

    2012-05-01

    We report the first angular diameter measurements of two classical Cepheids, FF Aql and T Vul, that we obtain using observations with the FLUOR instrument installed at the CHARA interferometric array. We derive average limb-darkened angular diameters of θLD = 0.878 ± 0.013 mas and θLD = 0.629 ± 0.013 mas, respectively, for FF Aql and T Vul. Combining these angular diameters with the HST-FGS trigonometric parallaxes leads to linear radii R = 33.6 ± 2.2 R⊙ and R = 35.6 ± 4.4 R⊙, respectively. The comparison with empirical and theoretical period-radius relations leads to the conclusion that these Cepheids are pulsating in their fundamental mode. The knowledge of this pulsation mode is of prime importance to calibrating the period-luminosity relation with a uniform sample of fundamental mode Cepheids.

  9. MUSTANG High Angular Resolution Sunyaev-Zel'dovich Effect Imaging of Sub-Structure in Four Galaxy Clusters

    CERN Document Server

    Korngut, P M; Reese, E D; Mason, B S; Devlin, M J; Mroczkowski, T; Sarazin, C L; Sun, M; Sievers, J

    2010-01-01

    We present 10" to 18" images of four massive clusters of galaxies through the Sunyaev-Zel'dovich Effect (SZE). These measurements, made at 90~GHz with the MUSTANG receiver on the Green Bank Telescope (GBT), reveal pressure sub-structure to the intra-cluster medium (ICM) in three of the four systems. We identify the likely presence of a previously unknown weak shock-front in MACS0744+3927. By fitting the Rankine-Hugoniot density jump conditions in a complementary SZE/X-ray analysis, we infer a Mach number of M = 1.2^{+0.2}_{-0.2} and a shock-velocity of 1827^{+267}_{-195}~km/s. In RXJ1347-1145, we present a new reduction of previously reported data and confirm the presence of a south-east SZE enhancement with a significance of 13.9 sigma when smoothed to 18" resolution. This too is likely caused by shock-heated gas produced in a recent merger. In our highest redshift system, CL1226+3332, we detect sub-structure at a peak significance of 4.6 sigma in the form of a ridge oriented orthogonally to the vector conne...

  10. Atmospheric Corrections Using MODTRAN for TOA and Surface BRDF Characteristics from High Resolution Spectroradiometric/Angular Measurements from a Helicopter Platform

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    High-resolution spectral radiance measurements were taken by a spectral radiometer on board a heli copter over the US Oklahoma Southern Great Plain near the Atmospheric Radiation Measurements (ARM) site during August 1998. The radiometer has a spectral range from 350 nm to 2500 nm at 1 nm resolution. The measurements covered several grass and cropland scene types at multiple solar zenith angles. Detailed atmospheric corrections using the Moderate Resolution Transmittance (MODTRAN) radiation model and in-situ sounding and aerosol measurements have been applied to the helicopter measurements in order to re trieve the surface and top of atmosphere (TOA) Bidirectional Reflectance Distribution Function (BRDF) characteristics. The atmospheric corrections are most significant in the visible wavelengths and in the strong water vapor absorption wavelengths in the near infrared region. Adjusting the BRDF to TOA requires a larger correction in the visible channels since Rayleigh scattering contributes significantly to the TOA reflectance. The opposite corrections to the visible and near infrarred wavelengths can alter the radiance dif ference and ratio that many remote sensing techniques are based on, such as the normalized difference vege tation index (NDVI). The data show that surface BRDFs and spectral albedos are highly sensitive to the veg etation type and solar zenith angle while BRDF at TOA depends more on atmospheric conditions and the vi ewing geometry. Comparison with the Clouds and the Earth's Radiant Energy System (CERES) derived clear sky Angular Distribution Model (ADM) for crop and grass scene type shows a standard deviation of 0.08 in broadband anisotropic function at 25° solar zenith angle and 0.15 at 50° solar zenith angle, respectively.

  11. Understanding Active Galactic Nuclei using near-infrared high angular resolution polarimetry I : MontAGN - STOKES comparison

    Science.gov (United States)

    Grosset, L.; Marin, F.; Gratadour, D.; Goosmann, R.; Rouan, D.; Clénet, Y.; Pelat, D.; Rojas Lobos, P. A.

    2016-12-01

    In this first research note of a series of two, we present a comparison between two Monte Carlo radiative transfer codes: MontAGN and STOKES. Both were developed in order to better understand the observed polarisation of Active Galactic Nuclei (AGN). Our final aim is to use these radiative transfer codes to simulate the polarisation maps of a prototypical type-2 radio-quiet AGN on a wide range of wavelengths, from the infrared band with MontAGN to the X-ray energies with STOKES. Doing so, we aim to analyse in depth the recent SPHERE/IRDIS polarimetric observations conducted on NGC 1068. In order to validate the codes and obtain preliminary results, we set for both codes a common and simple AGN model, and compared their polaro-imaging results.

  12. Understanding active galactic nuclei using near-infrared high angular resolution polarimetry I : MontAGN - stokes comparison

    CERN Document Server

    Grosset, Lucas; Gratadour, Damien; Goosmann, René; Rouan, Daniel; Clénet, Yann; Pelat, Didier; Lobos, Patricia Andrea Rojas

    2016-01-01

    In this first research note of a series of two, we present a comparison between two Monte Carlo radiative transfer codes: MontAGN and STOKES. Both were developed in order to better understand the observed polarisation of Active Galactic Nuclei (AGN). Our final aim is to use these radiative transfer codes to simulate the polarisation maps of a prototypical type-2 radio-quiet AGN on a wide range of wavelengths, from the infrared band with MontAGN to the X-ray energies with STOKES. Doing so, we aim to analyse in depth the recent SPHERE/IRDIS polarimetric observations conducted on NGC 1068. In order to validate the codes and obtain preliminary results, we set for both codes a common and simple AGN model, and compared their polaro-imaging results.

  13. Giant quiescent solar filament observed with high-resolution spectroscopy

    Science.gov (United States)

    Kuckein, C.; Verma, M.; Denker, C.

    2016-05-01

    Aims: An extremely large filament was studied in various layers of the solar atmosphere. The inferred physical parameters and the morphological aspects are compared with smaller quiescent filaments. Methods: A giant quiet-Sun filament was observed with the high-resolution Echelle spectrograph at the Vacuum Tower Telescope at Observatorio del Teide, Tenerife, Spain, on 2011 November 15. A mosaic of spectra (ten maps of 100″ × 182″) was recorded simultaneously in the chromospheric absorption lines Hα and Na i D2. Physical parameters of the filament plasma were derived using cloud model (CM) inversions and line core fits. The spectra were complemented with full-disk filtergrams (He i λ10830 Å, Hα, and Ca ii K) of the Chromospheric Telescope (ChroTel) and full-disk magnetograms of the Helioseismic and Magnetic Imager (HMI). Results: The filament had extremely large linear dimensions (~817 arcsec), which corresponds to about 658 Mm along a great circle on the solar surface. A total amount of 175119 Hα contrast profiles were inverted using the CM approach. The inferred mean line-of-sight (LOS) velocity, Doppler width, and source function were similar to previous works of smaller quiescent filaments. However, the derived optical thickness was higher. LOS velocity trends inferred from the Hα line core fits were in accord but weaker than those obtained with CM inversions. Signatures of counter-streaming flows were detected in the filament. The largest brightening conglomerates in the line core of Na i D2 coincided well with small-scale magnetic fields as seen by HMI. Mixed magnetic polarities were detected close to the ends of barbs. The computation of photospheric horizontal flows based on HMI magnetograms revealed flow kernels with a size of 5-8 Mm and velocities of 0.30-0.45 km s-1 at the ends of the filament. Conclusions: The physical properties of extremely large filaments are similar to their smaller counterparts, except for the optical thickness, which in

  14. Evolution of deformation structures under varying loading conditions followed in situ by high angular resolution 3DXRD

    DEFF Research Database (Denmark)

    Pantleon, Wolfgang; Wejdemann, Christian; Jakobsen, B.;

    2009-01-01

    intermittently. When the traction is terminated, stress relaxation occurs and number, size and orientation of subgrains are found to be constant. The subgrain structure freezes and only a minor clean-up of the dislocation structure is observed. When changing the tensile direction after pre-deformation in tension......, a systematic correlation between the degree of strain path change and the changes in the dislocation structure quantified by the volume fraction of the subgrains is established. For obtaining the subgrain volume fraction, a new fitting method has been developed for partitioning the contributions of subgrains...

  15. Molecule sublimation as a tracer of protostellar accretion: Evidence for accretion bursts from high angular resolution C18O images

    CERN Document Server

    Jorgensen, Jes K; Williams, Jonathan P; Bergin, Edwin A

    2015-01-01

    The accretion histories of embedded protostars are an integral part of descriptions of their physical and chemical evolution. In particular, are the accretion rates smoothly declining from the earlier toward later stages or in fact characterized by variations such as intermittent bursts? We aim to characterize the impact of possible accretion variations in a sample of embedded protostars by measuring the size of the inner regions of their envelopes where CO is sublimated and relate those to their temperature profiles dictated by their current luminosities. Using observations from the Submillimeter Array we measure the extents of the emission from the C18O isotopologue toward 16 deeply embedded protostars. We compare these measurements to the predicted extent of the emission given the current luminosities of the sources through dust and line radiative transfer calculations. Eight out of sixteen sources show more extended C18O emission than predicted by the models. The modeling shows that the likely culprit for...

  16. Reference resolution in multi-modal interaction: Preliminary observations

    NARCIS (Netherlands)

    Nijholt, A.; González González, G.R.

    2002-01-01

    In this paper we present our research on multimodal interaction in and with virtual environments. The aim of this presentation is to emphasize the necessity to spend more research on reference resolution in multimodal contexts. In multi-modal interaction the human conversational partner can apply mo

  17. Stellar Diameters and Temperatures VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs

    CERN Document Server

    Boyajian, Tabetha; Feiden, Gregory A; Huber, Daniel; Basu, Sarbani; Demarque, Pierre; Fischer, Debra A; Schaefer, Gail; Mann, Andrew W; White, Timothy R; Maestro, Vicente; Brewer, John; Lamell, C Brooke; Spada, Federico; López-Morales, Mercedes; Ireland, Michael; Farrington, Chris; van Belle, Gerard T; Kane, Stephen R; Jones, Jeremy; Brummelaar, Theo A ten; Ciardi, David R; McAlister, Harold A; Ridgway, Stephen; Goldfinger, P J; Turner, Nils H; Sturmann, Laszlo

    2014-01-01

    We present direct radii measurements of the well-known transiting exoplanet host stars HD 189733 and HD 209458 using the CHARA Array interferometer. We find the limb-darkened angular diameters to be theta_LD = 0.3848 +/- 0.0055 and 0.2254 +/- 0.0072 milliarcsec for HD 189733 and HD 209458, respectively. HD 189733 and HD 209458 are currently the only two transiting exoplanet systems where detection of the respective planetary companion's orbital motion from high resolution spectroscopy has revealed absolute masses for both star and planet. We use our new measurements together with the orbital information from radial velocity and photometric time series data, Hipparcos distances, and newly measured bolometric fluxes to determine the stellar effective temperatures (T_eff = 4875 +/- 43, 6093 +/- 103 K), stellar linear radii (R_* = 0.805 +/- 0.016, 1.203 +/- 0.061 R_sun), mean stellar densities (rho_* = 1.62 +/- 0.11, 0.58 +/- 0.14 rho_sun), planetary radii (R_p = 1.216 +/- 0.024, 1.451 +/- 0.074 R_Jup), and mean ...

  18. A deep look at the nuclear region of UGC 5101 through high angular resolution mid-IR data with GTC/CanariCam

    CERN Document Server

    Martínez-Paredes, M; Aretxaga, I; Almeida, C Ramos; Hernán-Caballero, A; González-Martín, O; Pereira-Santaella, M; Packham, C; Ramos, A Asensio; Díaz-Santos, T; Elitzur, M; Esquej, P; García-Bernete, I; Imanishi, M; Levenson, N A; Espinosa, J M Rodríguez

    2015-01-01

    We present an analysis of the nuclear infrared (IR, 1.6 to 18 $\\mu$m) emission of the ultraluminous IR galaxy UGC 5101 to derive the properties of its active galactic nucleus (AGN) and its obscuring material. We use new mid-IR high angular resolution ($0.3-0.5$ arcsec) imaging using the Si-2 filter ($\\lambda_{C}=8.7\\, \\mu$m) and $7.5-13$ $\\mu$m spectroscopy taken with CanariCam (CC) on the 10.4m Gran Telescopio CANARIAS. We also use archival HST/NICMOS and Subaru/COMICS imaging and Spitzer/IRS spectroscopy. We estimate the near- and mid-IR unresolved nuclear emission by modelling the imaging data with GALFIT. We decompose the Spitzer/IRS and CC spectra using a power-law component, which represents the emission due to dust heated by the AGN, and a starburst component, both affected by foreground extinction. We model the resulting unresolved near- and mid-IR, and the starburst subtracted CC spectrum with the CLUMPY torus models of Nenkova et al. The derived geometrical properties of the torus, including the lar...

  19. Angular resolution measurements at SPring-8 of a hard X-ray optic for the New Hard X-ray Mission

    CERN Document Server

    Spiga, D; Furuzawa, A; Basso, S; Binda, R; Borghi, G; Cotroneo, V; Grisoni, G; Kunieda, H; Marioni, F; Matsumoto, H; Mori, H; Miyazawa, T; Negri, B; Orlandi, A; Pareschi, G; Salmaso, B; Tagliaferri, G; Uesugi, K; Valsecchi, G; Vernani, D

    2015-01-01

    The realization of X-ray telescopes with imaging capabilities in the hard (> 10 keV) X-ray band requires the adoption of optics with shallow (10 m shall be produced and tested. Full-illumination tests of such mirrors are usually performed with on- ground X-ray facilities, aimed at measuring their effective area and the angular resolution; however, they in general suffer from effects of the finite distance of the X-ray source, e.g. a loss of effective area for double reflection. These effects increase with the focal length of the mirror under test; hence a "partial" full-illumination measurement might not be fully representative of the in-flight performances. Indeed, a pencil beam test can be adopted to overcome this shortcoming, because a sector at a time is exposed to the X-ray flux, and the compensation of the beam divergence is achieved by tilting the optic. In this work we present the result of a hard X-ray test campaign performed at the BL20B2 beamline of the SPring-8 synchrotron radiation facility, aime...

  20. Adaptive smoothing of high angular resolution diffusion-weighted imaging data by generalized cross-validation improves Q-ball orientation distribution function reconstruction.

    Science.gov (United States)

    Metwalli, Nader S; Hu, Xiaoping P; Carew, John D

    2010-09-01

    Q-ball imaging (QBI) is a high angular resolution diffusion-weighted imaging (HARDI) technique for reconstructing the orientation distribution function (ODF). Some form of smoothing or regularization is typically required in the ODF reconstruction from low signal-to-noise ratio HARDI data. The amount of smoothing or regularization is usually set a priori at the discretion of the investigator. In this article, we apply an adaptive and objective means of smoothing the raw HARDI data using the smoothing splines on the sphere method with generalized cross-validation (GCV) to estimate the diffusivity profile in each voxel. Subsequently, we reconstruct the ODF, from the smoothed data, based on the Funk-Radon transform (FRT) used in QBI. The spline method was applied to both simulated data and in vivo human brain data. Simulated data show that the smoothing splines on the sphere method with GCV smoothing reduces the mean squared error in estimates of the ODF as compared with the standard analytical QBI approach. The human data demonstrate the utility of the method for estimating smooth ODFs.

  1. A statistical analysis of angular distribution of neutrino events observed in Kamiokande II and IMB detectors from supernova SN 1987 A

    Energy Technology Data Exchange (ETDEWEB)

    Krivoruchenko, M.I. (Institut Teoreticheskoj i Ehksperimental' noj Fiziki, Moscow (USSR))

    1989-11-01

    A detailed statistical analysis of angular distribution of neutrino events observed in Kamiokande II and IMB detectors on UT 07:35, 2/23'87 is carried out. Distribution functions of the mean scattering angles in the reaction anti 4u{sub e}p->e{sup +}n and 4ue->4ue are constructed with account taken of the multiple Coulomb scattering and the experimental angular errors. The Smirnov and Wald-Wolfowitz run tests are used to test the hypothesis that the angular distributions of events from the two detectors agree with each other. We test with the use of the Kolmogorov and Mises statistical criterions the hypothesis that the recorded events all represent anti 4u{sub e}p->e{sup +}n inelastic scatterings. Then the Neyman-Pearson test is applied to each event in testing the hypothesis anti 4u{sub e}p->e{sup +}n against the alternative 4ue->4ue. The hypotheses that the number of elastic events equals s=0, 1, 2, ... against the alternatives snot =0, 1, 2, ... are tested on the basis of the generalized likelihood ratio criterion. The confidence intervals for the number of elastic events are also constructed. The current supernova models fail to give a satisfactory account of the angular distribution data. (orig.).

  2. Angular magnetoresistance in semiconducting undoped amorphous carbon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sagar, Rizwan Ur Rehman; Saleemi, Awais Siddique; Zhang, Xiaozhong, E-mail: xzzhang@tsinghua.edu.cn [Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, People' s Republic of China and Beijing National Center for Electron Microscopy, Beijing 100084 (China)

    2015-05-07

    Thin films of undoped amorphous carbon thin film were fabricated by using Chemical Vapor Deposition and their structure was investigated by using High Resolution Transmission Electron Microscopy and Raman Spectroscopy. Angular magnetoresistance (MR) has been observed for the first time in these undoped amorphous carbon thin films in temperature range of 2 ∼ 40 K. The maximum magnitude of angular MR was in the range of 9.5% ∼ 1.5% in 2 ∼ 40 K. The origin of this angular MR was also discussed.

  3. Time-differential observation of alpha -particle perturbed angular distribution; g-factor measurements for /sup 217/Ac/sup gs/ and /sup 217/Ac/sup m/

    CERN Document Server

    Maier, K H; Grawe, H; Kluge, H

    1981-01-01

    The g-factor measurements of the ground state and an isomeric level in /sup 217/Ac using the DPAD method with alpha -decay are described. The results of gamma -ray g-factor measurements for the isomer and a tentative decay scheme produced by alpha - gamma and gamma - gamma coincidence experiments are also presented. An analysis of the alpha - particle angular distributions suggests that nuclear deformation affects the observed anisotropy. (13 refs).

  4. Recurrence of angular cheilitis.

    Science.gov (United States)

    Ohman, S C; Jontell, M; Dahlen, G

    1988-08-01

    The incidence of recurrence of angular cheilitis following a successful antimicrobial treatment was studied in 48 patients. Clinical assessments including a microbial examination were carried out 8 months and 5 yr after termination of treatment. Eighty percent of the patients reported recurrence of their angular cheilitis on one or more occasions during the observation period. Patients with cutaneous disorders associated with dry skin or intraoral leukoplakia had an increased incidence of recrudescence. Neither the presence of denture stomatitis nor the type of microorganisms isolated from the original lesions of angular cheilitis, i.e. Candida albicans and/or Staphylococcus aureus, were associated with the number of recurrences. The present observations indicate that treatment of the majority of patients with angular cheilitis should be considered in a longer perspective than previously supposed, due to the short lasting therapeutic effects of the antimicrobial therapy.

  5. Aerosol classification by airborne high spectral resolution lidar observations

    Science.gov (United States)

    Groß, S.; Esselborn, M.; Weinzierl, B.; Wirth, M.; Fix, A.; Petzold, A.

    2013-03-01

    During four aircraft field experiments with the DLR research aircraft Falcon in 1998 (LACE), 2006 (SAMUM-1) and 2008 (SAMUM-2 and EUCAARI), airborne High Spectral Resolution Lidar (HSRL) and in situ measurements of aerosol microphysical and optical properties were performed. Altogether, the properties of six different aerosol types and aerosol mixtures - Saharan mineral dust, Saharan dust mixtures, Canadian biomass burning aerosol, African biomass burning mixture, anthropogenic pollution aerosol, and marine aerosol have been studied. On the basis of this extensive HSRL data set, we present an aerosol classification scheme which is also capable to identify mixtures of different aerosol types. We calculated mixing lines that allowed us to determine the contributing aerosol types. The aerosol classification scheme was supported by backward trajectory analysis and validated with in-situ measurements. Our results demonstrate that the developed aerosol mask is capable to identify complex stratifications with different aerosol types throughout the atmosphere.

  6. Aerosol classification by airborne high spectral resolution lidar observations

    Directory of Open Access Journals (Sweden)

    S. Groß

    2012-10-01

    Full Text Available During four aircraft field experiments with the DLR research aircraft Falcon in 1998 (LACE, 2006 (SAMUM-1 and 2008 (SAMUM-2 and EUCAARI, airborne High Spectral Resolution Lidar (HSRL and in situ measurements of aerosol microphysical and optical properties were performed. Altogether, the properties of six different aerosol types and aerosol mixtures – Saharan mineral dust, Saharan dust mixtures, Canadian biomass burning aerosol, African biomass burning aerosol, anthropogenic pollution aerosol, and marine aerosol have been studied. On the basis of this extensive HSRL data set, we present an aerosol classification scheme which is also capable to identify mixtures of different aerosol types. We calculated mixing lines that allowed us to determine the contributing aerosol types. The aerosol classification scheme was validated with in-situ measurements and backward trajectory analyses. Our results demonstrate that the developed aerosol mask is capable to identify complex stratifications with different aerosol types throughout the atmosphere.

  7. Angular resolution measurements at SPring-8 of a hard x-ray optic for the New Hard X-ray Mission

    Science.gov (United States)

    Spiga, D.; Raimondi, L.; Furuzawa, A.; Basso, S.; Binda, R.; Borghi, G.; Cotroneo, V.; Grisoni, G.; Kunieda, H.; Marioni, F.; Matsumoto, H.; Mori, H.; Miyazawa, T.; Negri, B.; Orlandi, A.; Pareschi, G.; Salmaso, B.; Tagliaferri, G.; Uesugi, K.; Valsecchi, G.; Vernani, D.

    2011-09-01

    The realization of X-ray telescopes with imaging capabilities in the hard (> 10 keV) X-ray band requires the adoption of optics with shallow (=10 m shall be produced and tested. Full-illumination tests of such mirrors are usually performed with onground X-ray facilities, aimed at measuring their effective area and the angular resolution; however, they in general suffer from effects of the finite distance of the X-ray source, e.g. a loss of effective area for double reflection. These effects increase with the focal length of the mirror under test; hence a "partial" full-illumination measurement might not be fully representative of the in-flight performances. Indeed, a pencil beam test can be adopted to overcome this shortcoming, because a sector at a time is exposed to the X-ray flux, and the compensation of the beam divergence is achieved by tilting the optic. In this work we present the result of a hard X-ray test campaign performed at the BL20B2 beamline of the SPring-8 synchrotron radiation facility, aimed at characterizing the Point Spread Function (PSF) of a multilayer-coated Wolter-I mirror shell manufactured by Nickel electroforming. The mirror shell is a demonstrator for the NHXM hard X-ray imaging telescope (0.3 - 80 keV), with a predicted HEW (Half Energy Width) close to 20 arcsec. We show some reconstructed PSFs at monochromatic X-ray energies of 15 to 63 keV, and compare them with the PSFs computed from post-campaign metrology data, self-consistently treating profile and roughness data by means of a method based on the Fresnel diffraction theory. The modeling matches the measured PSFs accurately.

  8. Angular Momentum

    Science.gov (United States)

    Shakur, Asif; Sinatra, Taylor

    2013-01-01

    The gyroscope in a smartphone was employed in a physics laboratory setting to verify the conservation of angular momentum and the nonconservation of rotational kinetic energy. As is well-known, smartphones are ubiquitous on college campuses. These devices have a panoply of built-in sensors. This creates a unique opportunity for a new paradigm in…

  9. High Resolution Observations using Adaptive Optics: Achievements and Future Needs

    Indian Academy of Sciences (India)

    K. Sankarasubramanian; T. Rimmele

    2008-03-01

    Over the last few years, several interesting observations were obtained with the help of solar Adaptive Optics (AO). In this paper, few observations made using the solarAOare enlightened and briefly discussed. A list of disadvantages with the current AO system are presented. With telescopes larger than 1.5 m expected during the next decade, there is a need to develop the existing AO technologies for large aperture telescopes. Some aspects of this development are highlighted. Finally, the recent AO developments in India are also presented.

  10. Observation of Anisotropy in the Arrival Directions of Galactic Cosmic Rays at Multiple Angular Scales with IceCube

    CERN Document Server

    Abbasi, R; Abu-Zayyad, T; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Bay, R; Alba, J L Bazo; Beattie, K; Beatty, J J; Bechet, S; Becker, J K; Becker, K -H; Benabderrahmane, M L; BenZvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohm, C; Bose, D; Böser, S; Botner, O; Brown, A M; Buitink, S; Caballero-Mora, K S; Carson, M; Chirkin, D; Christy, B; Clem, J; Clevermann, F; Cohen, S; Colnard, C; Cowen, D F; D'Agostino, M V; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; Demirörs, L; Denger, T; Depaepe, O; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; Díaz-Vélez, J C; Dierckxsens, M; Dreyer, J; Dumm, J P; Ehrlich, R; Eisch, J; Ellsworth, R W; Engdegård, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Foerster, M M; Fox, B D; Franckowiak, A; Franke, R; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Goodman, J A; Gora, D; Grant, D; Griesel, T; Groß, A; Grullon, S; Gurtner, M; Ha, C; Hajismail, A; Hallgren, A; Halzen, F; Han, K; Hanson, K; Heinen, D; Helbing, K; Herquet, P; Hickford, S; Hill, G C; Hoffman, K D; Homeier, A; Hoshina, K; Hubert, D; Huelsnitz, W; a,; Hülß, J -P; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobsen, J; Japaridze, G S; Johansson, H; Joseph, J M; Kampert, K -H; Kappes, A; Karg, T; Karle, A; Kenny, P; Kiryluk, J; Kislat, F; Klein, S R; Köhne, J -H; Kohnen, G; Kolanoski, H; Köpke, L; Kopper, S; Koskinen, D J; Kowalski, M; Kowarik, T; Krasberg, M; Krings, T; Kroll, G; Kurahashi, N; Kuwabara, T; Labare, M; Lafebre, S; Laihem, K; Landsman, H; Larson, M J; Lauer, R; Lünemann, J; Madajczyk, B; Madsen, J; Majumdar, P; Marotta, A; Maruyama, R; Mase, K; Matis, H S; Meagher, K; Merck, M; Mészáros, P; Meures, T; Middell, E; Milke, N; Miller, J; Montaruli, T; b,; Morse, R; Movit, S M; Nahnhauer, R; Nam, J W; Naumann, U; Nießen, P; Nygren, D R; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Ono, M; Panknin, S; Paul, L; Heros, C Pérez de los; Petrovic, J; Piegsa, A; Pieloth, D; Porrata, R; Posselt, J; Price, C C; Price, P B; Przybylski, G T; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Rizzo, A; Rodrigues, J P; Roth, P; Rothmaier, F; Rott, C; Ruhe, T; Rutledge, D; Ruzybayev, B; Ryckbosch, D; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Schmidt, T; Schönwald, A; Schukraft, A; Schultes, A; Schulz, O; Schunck, M; Seckel, D; Semburg, B; Seo, S H; Sestayo, Y; Seunarine, S; Silvestri, A; Slipak, A; Spiczak, G M; Spiering, C; Stamatikos, M; c,; Stanev, T; Stephens, G; Stezelberger, T; Stokstad, R G; Stössl, A; Stoyanov, S; Strahler, E A; Straszheim, T; Stür, M; Sullivan, G W; Swillens, Q; Taavola, H; Taboada, I; Tamburro, A; Tepe, A; Ter-Antonyan, S; Tilav, S; Toale, P A; Toscano, S; Tosi, D; Turčan, D; van Eijndhoven, N; Vandenbroucke, J; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Weaver, Ch; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wischnewski, R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, X W; Yodh, G; Yoshida, S; Zarzhitsky, P; Zoll, M

    2011-01-01

    Between May 2009 and May 2010, the IceCube neutrino detector at the South Pole recorded 32 billion muons generated in air showers produced by cosmic rays with a median energy of 20 TeV. With a data set of this size, it is possible to probe the southern sky for per-mille anisotropy on all angular scales in the arrival direction distribution of cosmic rays. Applying a power spectrum analysis to the relative intensity map of the cosmic ray flux in the southern hemisphere, we show that the arrival direction distribution is not isotropic, but shows significant structure on several angular scales. In addition to previously reported large-scale structure in the form of a strong dipole and quadrupole, the data show small-scale structure on scales between 15 degrees and 30 degrees. The skymap exhibits several localized regions of significant excess and deficit in cosmic ray intensity. The relative intensity of the smaller-scale structures is about a factor of 5 weaker than that of the dipole and quadrupole structure. ...

  11. Numerical experiments on consistent horizontal and vertical resolution for atmospheric models and observing systems

    Science.gov (United States)

    Fox-Rabinovitz, Michael S.; Lindzen, Richard S.

    1993-01-01

    Simple numerical experiments are performed in order to determine the effects of inconsistent combinations of horizontal and vertical resolution in both atmospheric models and observing systems. In both cases, we find that inconsistent spatial resolution is associated with enhanced noise generation. A rather fine horizontal resolution in a satellite-data observing system seems to be excessive when combined with the usually available relatively coarse vertical resolution. Using horizontal filters of different strengths, adjusted in such a way as to render the effective horizontal resolution more consistent with vertical resolution for the observing system, may result in improvement of the analysis accuracy. The increase of vertical resolution for a satellite data observing system with better vertically resolved data, the results are different in that little or no horizontal filtering is needed to make spatial resolution more consistent for the system. The obtained experimental estimates of consistent vertical and effective horizontal resolution are in a general agreement with consistent resolution estimates previously derived theoretically by the authors.

  12. High spatial resolution VLA observations of the R Aquarii jet

    Science.gov (United States)

    Kafatos, M.; Hollis, J. M.; Michalitsianos, A. G.

    1983-01-01

    The Very Large Array was used to observe the jet feature of the symbiotic variable R Aquarii. A steady emission at 6 cm was confirmed for the past year, with the jet located 6.4 arcsec from R Aquarii at 29.3 deg PA. A velocity for the jet has been calculated as 40 km/sec, and may be accompanied by an ejection velocity in the range of 760-1800 km/sec. Since R Aquarii is the closest known object with a jet, further monitoring is recommended in order to detect any episodic mass transfer in what may be a binary system. The mass transfer, monitored at various wavelengths, would account for the observed optical and radio properties.

  13. Measuring gravitational lens time delays using low-resolution radio monitoring observations

    CERN Document Server

    Gurkan, G; Koopmans, L V E; Fassnacht, C D; Alba, A Berciano

    2014-01-01

    Obtaining lensing time delay measurements requires long-term monitoring campaigns with a high enough resolution (< 1 arcsec) to separate the multiple images. In the radio, a limited number of high-resolution interferometer arrays make these observations difficult to schedule. To overcome this problem, we propose a technique for measuring gravitational time delays which relies on monitoring the total flux density with low-resolution but high-sensitivity radio telescopes to follow the variation of the brighter image. This is then used to trigger high-resolution observations in optimal numbers which then reveal the variation in the fainter image. We present simulations to assess the efficiency of this method together with a pilot project observing radio lens systems with the Westerbork Synthesis Radio Telescope (WSRT) to trigger Very Large Array (VLA) observations. This new method is promising for measuring time delays because it uses relatively small amounts of time on high-resolution telescopes. This will b...

  14. Inference of mantle viscosity for depth resolutions of GIA observations

    Science.gov (United States)

    Nakada, Masao; Okuno, Jun'ichi

    2016-11-01

    Inference of the mantle viscosity from observations for glacial isostatic adjustment (GIA) process has usually been conducted through the analyses based on the simple three-layer viscosity model characterized by lithospheric thickness, upper- and lower-mantle viscosities. Here, we examine the viscosity structures for the simple three-layer viscosity model and also for the two-layer lower-mantle viscosity model defined by viscosities of η670,D (670-D km depth) and ηD,2891 (D-2891 km depth) with D-values of 1191, 1691 and 2191 km. The upper-mantle rheological parameters for the two-layer lower-mantle viscosity model are the same as those for the simple three-layer one. For the simple three-layer viscosity model, rate of change of degree-two zonal harmonics of geopotential due to GIA process (GIA-induced J˙2) of -(6.0-6.5) × 10-11 yr-1 provides two permissible viscosity solutions for the lower mantle, (7-20) × 1021 and (5-9) × 1022 Pa s, and the analyses with observational constraints of the J˙2 and Last Glacial Maximum (LGM) sea levels at Barbados and Bonaparte Gulf indicate (5-9) × 1022 Pa s for the lower mantle. However, the analyses for the J˙2 based on the two-layer lower-mantle viscosity model only require a viscosity layer higher than (5-10) × 1021 Pa s for a depth above the core-mantle boundary (CMB), in which the value of (5-10) × 1021 Pa s corresponds to the solution of (7-20) × 1021 Pa s for the simple three-layer one. Moreover, the analyses with the J˙2 and LGM sea level constraints for the two-layer lower-mantle viscosity model indicate two viscosity solutions: η670,1191 > 3 × 1021 and η1191,2891 ˜ (5-10) × 1022 Pa s, and η670,1691 > 1022 and η1691,2891 ˜ (5-10) × 1022 Pa s. The inferred upper-mantle viscosity for such solutions is (1-4) × 1020 Pa s similar to the estimate for the simple three-layer viscosity model. That is, these analyses require a high viscosity layer of (5-10) × 1022 Pa s at least in the deep mantle, and suggest

  15. The stellar mass-size relation for cluster galaxies at z = 1 with high angular resolution from the Gemini/GeMS multiconjugate adaptive optics system

    Science.gov (United States)

    Sweet, Sarah M.; Sharp, Robert; Glazebrook, Karl; Rigaut, Francois; Carrasco, Eleazar R.; Brodwin, Mark; Bayliss, Matthew; Stalder, Brian; Abraham, Roberto; McGregor, Peter

    2017-01-01

    We present the stellar mass-size relation for 49 galaxies within the z = 1.067 cluster SPT-CL J0546-5345, with full width at half-maximum ˜80-120 mas Ks-band data from the Gemini multiconjugate adaptive optics system (GeMS/GSAOI). This is the first such measurement in a cluster environment, performed at sub-kpc resolution at rest-frame wavelengths dominated by the light of the underlying old stellar populations. The observed stellar mass-size relation is offset from the local relation by 0.21 dex, corresponding to a size evolution proportional to (1 + z)-1.25, consistent with the literature. The slope of the stellar mass-size relation β = 0.74 ± 0.06, consistent with the local relation. The absence of slope evolution indicates that the amount of size growth is constant with stellar mass. This suggests that galaxies in massive clusters such as SPT-CL J0546-5345 grow via processes that increase the size without significant morphological interference, such as minor mergers and/or adiabatic expansion. The slope of the cluster stellar mass-size relation is significantly shallower if measured in Hubble Space Telescope (HST)/Advanced Camera for Surveys imaging at wavelengths blueward of the Balmer break, similar to rest-frame ultraviolet relations at z = 1 in the literature. The stellar mass-size relation must be measured at redder wavelengths, which are more sensitive to the old stellar population that dominates the stellar mass of the galaxies. The slope is unchanged when GeMS Ks-band imaging is degraded to the resolution of K-band HST/Near Infrared Camera and Multi-Object Spectrometer resolution but dramatically affected when degraded to Ks-band Magellan/FourStar resolution. Such measurements must be made with adaptive optics in order to accurately characterize the sizes of compact, z = 1 galaxies.

  16. Improving resolution and depth of astronomical observations via modern mathematical methods for image analysis

    CERN Document Server

    Castellano, Marco; Fontana, Adriano; Merlin, Emiliano; Pilo, Stefano; Falcone, Maurizio

    2015-01-01

    In the past years modern mathematical methods for image analysis have led to a revolution in many fields, from computer vision to scientific imaging. However, some recently developed image processing techniques successfully exploited by other sectors have been rarely, if ever, experimented on astronomical observations. We present here tests of two classes of variational image enhancement techniques: "structure-texture decomposition" and "super-resolution" showing that they are effective in improving the quality of observations. Structure-texture decomposition allows to recover faint sources previously hidden by the background noise, effectively increasing the depth of available observations. Super-resolution yields an higher-resolution and a better sampled image out of a set of low resolution frames, thus mitigating problematics in data analysis arising from the difference in resolution/sampling between different instruments, as in the case of EUCLID VIS and NIR imagers.

  17. High-Resolution Images of Diffuse Neutral Clouds in the Milky Way. I. Observations, Imaging, and Basic Cloud Properties

    CERN Document Server

    Pidopryhora, Yurii; Dickey, John M; Rupen, Michael P

    2015-01-01

    A set of diffuse interstellar clouds in the inner Galaxy within a few hundred pc of the Galactic plane has been observed at an angular resolution of ~1 arcmin combining data from the NRAO Green Bank Telescope and the Very Large Array. At the distance of the clouds the linear resolution ranges from ~1.9 pc to ~2.8 pc. These clouds have been selected to be somewhat out of the Galactic plane and are thus not confused with unrelated emission, but in other respects they are a Galactic population. They are located near the tangent points in the inner Galaxy, and thus at a quantifiable distance: $2.3 \\leq R \\leq 6.0$ kpc from the Galactic Center, and $-1000 \\leq z \\leq +610$ pc from the Galactic plane. These are the first images of the diffuse neutral HI clouds that may constitute a considerable fraction of the ISM. Peak HI column densities range from $N_{HI} = 0.8-2.9 \\times 10^{20}$ cm$^{-2}$. Cloud diameters vary between about 10 and 100 pc, and their HI mass spans the range from less than a hundred to a few thou...

  18. Observation of Ds1(2536)+ -> D+pi-K+ and angular decomposition of Ds1(2536)+ -> D*+K0S

    CERN Document Server

    Balagura, V; Aihara, H; Arinstein, K; Aulchenko, V; Aushev, T; Bakich, A M; Barberio, E; Bay, A; Belous, K S; Bhardwaj, V; Bitenc, U; Bondar, A; Bozek, A; Bracko, M; Brodzicka, J; Browder, T E; Chang, M C; Chao, Y; Chen, A; Chen, W T; Cheon, B G; Chistov, R; Cho, I S; Choi, Y; Dalseno, J; Danilov, M; Drutskoy, A; Eidelman, S; Epifanov, D; Gabyshev, N; Garmash, A; Golob, B; Ha, H; Haba, J; Hara, T; Hastings, N C; Hayasaka, K; Hayashii, H; Hazumi, M; Heffernan, D; Hoshi, Y; Hou, W S; Hyun, H J; Inami, K; Ishikawa, A; Ishino, H; Itoh, R; Iwasaki, M; Iwasaki, Y; Kah, D H; Kaji, H; Katayama, N; Kawai, H; Kawasaki, T; Kichimi, H; Kim, H J; Kim, H O; Kim, Y J; Kinoshita, K; Korpar, S; Krizan, P; Krokovny, P; Kuo, C C; Kuzmin, A; Kwon, Y J; Lange, J S; Lee, M J; Lee, S E; Lesiak, T; Limosani, A; Lin, S W; Liu, Y; Liventsev, D; Mandl, F; McOnie, S; Medvedeva, T; Mitaroff, W A; Miyake, H; Miyata, H; Miyazaki, Y; Mizuk, R; Mohapatra, D; Moloney, G R; Nagasaka, Y; Nakano, E; Nakao, M; Nakazawa, H; Natkaniec, Z; Nishida, S; Nitoh, O; Ogawa, S; Ohshima, T; Okuno, S; Olsen, S L; Ostrowicz, W; Ozaki, H; Pakhlov, P; Pakhlova, G; Palka, H; Park, C W; Peak, L S; Pestotnik, R; Piilonen, L E; Sakai, Y; Schneider, O; Senyo, K; Shapkin, M; Shen, C P; Shibuya, H; Shiu, J G; Somov, A; Stanic, S; Staric, M; Sumiyoshi, T; Tamai, K; Tanaka, M; Taylor, G N; Teramoto, Y; Tikhomirov, I; Uehara, S; Ueno, K; Uglov, T; Unno, Y; Uno, S; Urquijo, P; Usov, Yu; Varner, G; Vervink, K; Villa, S; Vinokurova, A; Wang, C C; Wang, C H; Wang, M Z; Wang, P; Wang, X L; Watanabe, Y; Won, E; Yabsley, B D; Yamaguchi, A; Yamashita, Y; Yamauchi, M; Zhang, Z P; Zhilich, V; Zhulanov, V; Zupanc, A; Zyukova, O

    2007-01-01

    Using 462/fb of e+e- annihilation data recorded by the Belle detector, we report the first observation of the decay Ds1(2536)+ -> D+pi-K+. The ratio of branching fractions B(Ds1+ -> D+pi-K+)/B(Ds1+ -> D*+K0) is measured to be (3.27+-0.18+-0.37)%. We also study the angular distributions in the Ds1(2536)+ -> D*+K0S decay and measure the ratio of D- and S-wave amplitudes. The S-wave dominates, with a partial width of Gamma_S/Gamma_total=0.72+-0.05+-0.01.

  19. Aerosol Properties from Multi-spectral and Multi-angular Aircraft 4STAR Observations: Expected Advantages and Challenges

    Energy Technology Data Exchange (ETDEWEB)

    Kassianov, Evgueni I.; Flynn, Connor J.; Redemann, Jens; Schmid, Beat; Russell, P. B.; Sinyuk, Alexander

    2012-11-01

    The airborne Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) is developed to retrieve aerosol microphysical and optical properties from multi-angular and multi-spectral measurements of sky radiance and direct-beam sun transmittance. The necessarily compact design of the 4STAR may cause noticeable apparent enhancement of sky radiance at small scattering angles. We assess the sensitivity of expected 4STAR-based aerosol retrieval to such enhancement by applying the operational AERONET retrieval code and constructed synthetic 4STARlike data. Also, we assess the sensitivity of the broadband fluxes and the direct aerosol radiative forcing to uncertainties in aerosol retrievals associated with the sky radiance enhancement. Our sensitivity study results suggest that the 4STARbased aerosol retrieval has limitations in obtaining detailed information on particle size distribution and scattering phase function. However, these limitations have small impact on the retrieved bulk optical parameters, such as the asymmetry factor (up to 4%, or ±0.02) and single-scattering albedo (up to 2%, or ±0.02), and the calculated direct aerosol radiative forcing (up to 6%, or 2 Wm-2).

  20. Ultra-sensitive and super-resolving angular rotation measurement based on photon orbital angular momentum using parity measurement.

    Science.gov (United States)

    Zhang, Zijing; Qiao, Tianyuan; Ma, Kun; Cen, Longzhu; Zhang, Jiandong; Wang, Feng; Zhao, Yuan

    2016-08-15

    Photon orbital angular momentum has led to many novel insights and applications in quantum measurement. Photon orbital angular momentum can increase the resolution and sensitivity of angular rotation measurement. However, quantum measurement strategy can further surpass this limit and improve the resolution of angular rotation measurement. This Letter proposes and demonstrates a parity measurement method in angular rotation measurement scheme for the first time. Parity measurement can make the resolution superior to the limit of the existing method. The sensitivity can be improved with higher orbital angular momentum photons. Moreover, this Letter gives a detailed discussion of the change of resolution and sensitivity in the presence of photon loss.

  1. GroundBIRD: Observing Cosmic Microwave Polarization at Large Angular Scale with Kinetic Inductance Detectors and High-Speed Rotating Telescope

    Science.gov (United States)

    Oguri, S.; Choi, J.; Damayanthi, T.; Hattori, M.; Hazumi, M.; Ishitsuka, H.; Karatsu, K.; Mima, S.; Minowa, M.; Nagasaki, T.; Otani, C.; Sekimoto, Y.; Tajima, O.; Tomita, N.; Yoshida, M.; Won, E.

    2016-08-01

    Cosmic microwave background (CMB) is an important source of information about the origin of our universe. In particular, odd-parity large angular scale patterns in the CMB polarization, the primordial B-modes, are strong evidence for an inflationary universe, related to the accelerating expansion of the metric. We are developing a unique telescope, GroundBIRD, to take CMB polarization measurements. The telescope combines novel techniques: high-speed rotation scanning, cold optics, and microwave kinetic inductance detectors (MKIDs). We evaluated the response of MKIDs on the rotation stage. Method of shielding from the geo-magnetic field is established. We have also developed a receiver cryostat. We are able to maintain a sufficient cold status for observations on the optical configuration. We plan to start commissioning the system by observing CMB in Japan in 2015-2016. We will then deploy GroundBIRD in the Canary Islands for further scientific observations.

  2. The effect of sensor resolution on the number of cloud-free observations from space

    Directory of Open Access Journals (Sweden)

    J. M. Krijger

    2006-06-01

    Full Text Available Air quality and surface emission inversions are likely to be focal points for future satellite missions on atmospheric composition. Most important for these applications is sensitivity to the atmospheric composition in the lowest few kilometers of the troposphere. Reduced sensitivity by clouds needs to be minimized. In this study we have quantified the increase in number of useful footprints, i.e. footprints which are sufficient cloud-free, as a function of sensor resolution (footprint area. High resolution (1 km×1 km MODIS TERRA cloud mask observations are aggregated to lower resolutions. Statistics for different thresholds on cloudiness are applied. For each month in 2004 two days of MODIS data are analyzed. Globally the fraction of cloud-free observations drops from 16% at 100 km2 resolution to only 3% at 10 000 km2 if not a single MODIS observation within a footprint is allowed to be cloudy. If up to 5% or 20% of a footprint is allowed to be cloudy, the fraction of cloud-free observations is 9% or 17%, respectively, at 10 000 km2 resolution. The probability of finding cloud-free observations for different sensor resolutions is also quantified as a function of geolocation and season, showing examples over Europe and northern South America.

  3. Calibration of Angular Systematic Errors for High Resolution Satellite Imagery%高分辨率卫星遥感影像姿态角系统误差检校

    Institute of Scientific and Technical Information of China (English)

    袁修孝; 余翔

    2012-01-01

    The object positioning accuracy from high resolution satellite imagery is strongly relevant to image attitude data accuracy, but the attitude data have generally systematic errors and the object location becomes unreliable. The angular systematic error calibration model is stricter than constant angular error calibration model, based on the rigorous geometric processing model of high resolution satellite remote sensing imagery. The calibration model was tested on SPOT-5 and CBERS-02B images and both have proved its correctness. After compensating the angular systematic errors of images, the direct georeferencing accuracy can reach ±(2-3) pixels, which is much better than results of constant angular calibration.%简要介绍高分辨率卫星遥感影像的严格几何处理模型,提出较为严密的影像姿态角系统误差检校模型。通过对SPOT-5、CBERS-02B两种卫星遥感影像的试验证实模型的正确性和方法的有效性。对影像姿态角系统误差进行补偿后,可明显提高卫星遥感影像对地目标定位的精度,且优于影像姿态角常差检校的效果,目标点平面定位精度达到了±(2-~3)像素的水平。

  4. Measurement of the Black Hole Mass in NGC 1332 from ALMA Observations at 0.044 Arcsecond Resolution

    CERN Document Server

    Barth, Aaron J; Darling, Jeremy; Baker, Andrew J; Buote, David A; Ho, Luis C; Walsh, Jonelle L

    2016-01-01

    We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 3 observations of CO(2-1) emission from the circumnuclear disk in the E/S0 galaxy NGC 1332 at 0.044" resolution. The disk exhibits regular rotational kinematics and central high-velocity emission (+/-500 km/s) consistent with the presence of a compact central mass. We construct models for a thin, dynamically cold disk in the gravitational potential of the host galaxy and black hole, and fit the beam-smeared model line profiles directly to the ALMA data cube. Model fits successfully reproduce the disk kinematics out to r=200 pc. Fitting models just to spatial pixels within projected r=50 pc of the nucleus (two times larger than the black hole's gravitational radius of influence), we find M_BH=6.64(-0.63,+0.65)*10^8 solar masses. This observation demonstrates ALMA's powerful capability to determine the masses of supermassive black holes by resolving gas kinematics on small angular scales in galaxy nuclei.

  5. Measurement of the Black Hole Mass in NGC 1332 from ALMA Observations at 0.044 arcsecond Resolution

    Science.gov (United States)

    Barth, Aaron J.; Boizelle, Benjamin D.; Darling, Jeremy; Baker, Andrew J.; Buote, David A.; Ho, Luis C.; Walsh, Jonelle L.

    2016-05-01

    We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 3 observations of CO(2-1) emission from the circumnuclear disk in the E/S0 galaxy NGC 1332 at 0.″044 resolution. The disk exhibits regular rotational kinematics and central high-velocity emission (±500 km s-1) consistent with the presence of a compact central mass. We construct models for a thin, dynamically cold disk in the gravitational potential of the host galaxy and black hole and fit the beam-smeared model line profiles directly to the ALMA data cube. Model fits successfully reproduce the disk kinematics out to r = 200 pc. Fitting models just to spatial pixels within projected r = 50 pc of the nucleus (two times larger than the black hole’s gravitational radius of influence), we find {M}{BH}=({6.64}-0.63+0.65)× {10}8 {M}⊙ . This observation demonstrates ALMA’s powerful capability to determine the masses of supermassive black holes by resolving gas kinematics on small angular scales in galaxy nuclei.

  6. High-spatial-resolution microwave and related observations as diagnostics of coronal loops

    Science.gov (United States)

    Holman, Gordon D.

    1986-01-01

    High spatial resolution microwave observations of coronal loops, together with theoretical models for the loop emission, can provide detailed information about the temperature, density, and magnetic field within the loop, as well as the environment around the loop. The capability for studying magnetic fields is particularly important, since there is no comparable method for obtaining direct information about coronal magnetic fields. Knowledge of the magnetic field strength and structure in coronal loops is important for understanding both coronal heating and flares. With arc-second-resolution microwave observations from the Very Large Array (VLA), supplemental high-spectral-resolution microwave data from a facility such as the Owens Valley frequency-agile interferometer, and the ability to obtain second-of-arc resolution EUV aor soft X ray images, the capability already exists for obtaining much more detailed information about coronal plasma and magnetic structures than is presently available. This capability is discussed.

  7. Angular Velocity's Neural Network Observer of the Electric Drive of TVR - IM Type Implemented in Software Environment LabVIEW

    Science.gov (United States)

    Kozlova, L.; Bolovin, E.; Payuk, L.

    2016-06-01

    One of the common ways to manage a smooth starting and stopping of asynchronous motors are soft-start system. For this provision is necessary to use a closed speed asynchronous electric drive of tiristor voltage regulator - induction motor (TVR-IM) type. Using real sensors significantly increases the cost of installation and also introduces a number of inconveniences in the operation of the actuator. Observer has clear advantages that are created on artificial neural network. Creating a neural network observer in program graphic programming LabVIEW will allow to evaluate the speed of rotation of the asynchronous electric.

  8. Angular pattern of interferometers for scalar gravitational waves in the gauge of the local observer used for a potential detection of a stochastic bacground with advanced LIGO

    CERN Document Server

    Corda, C

    2006-01-01

    Recently, with the ``bounching photon'' treatment, the gauge invariance of the response of an interferometer to scalar gravitational waves (SGWs) has been demonstred in its full frequency dependence in three different gauges well known in literature, while in previous works it was been shown only in the low frequencies approximation. In this paper the analysis of the response function for SGWs is generalized in its full angular dependence and directly in the gauge of the local observer, which is the gauge of a laboratory enviroment on Earth. The result is used for anlyzing the cross - correlation between the two LIGO interferometers in their advanced configuration for a potential detection of a stochastic bacground of SGWs. An inferior limit for the integration time of a potential detection is released.

  9. Angular Velocity's Neural Network Observer of the Electric Drive of TVR - IM Type Implemented in Software Environment LabVIEW

    OpenAIRE

    2016-01-01

    One of the common ways to manage a smooth starting and stopping of asynchronous motors are soft-start system. For this provision is necessary to use a closed speed asynchronous electric drive of tiristor voltage regulator - induction motor (TVR-IM) type. Using real sensors significantly increases the cost of installation and also introduces a number of inconveniences in the operation of the actuator. Observer has clear advantages that are created on artificial neural network. Creating a neura...

  10. A Multi-Transition Study of Molecules toward NGC 1068 based on High-Resolution Imaging Observations with ALMA

    CERN Document Server

    Nakajima, Taku; Kohno, Kotaro; Harada, Nanase; Herbst, Eric; Tamura, Yoichi; Izumi, Takuma; Taniguchi, Akio; Tosaki, Tomoka

    2014-01-01

    We present 0.8-mm band molecular images and spectra obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) toward one of the nearest galaxies with an active galactic nucleus (AGN), NGC 1068. Distributions of CO isotopic species ($^{13}$CO and C$^{18}$O) $\\it{J}$ = 3--2, CN $\\it{N}$ = 3--2 and CS $\\it{J}$ = 7--6 are observed toward the circumnuclear disk (CND) and a part of the starburst ring with an angular resolution of $\\sim$1.$^{\\prime\\prime}$3 $\\times$ 1.$^{\\prime\\prime}$2. The physical properties of these molecules and shock-related molecules such as HNCO, CH$_{3}$CN, SO, and CH$_{3}$OH detected in the 3-mm band were estimated using rotation diagrams under the assumption of local thermodynamic equilibrium. The rotational temperatures of the CO isotopic species and the shock-related molecules in the CND are, respectively, 14--22 K and upper limits of 20--40 K. Although the column densities of the CO isotopic species in the CND are only from one-fifth to one-third of that in the starburst ri...

  11. MERIS full-resolution total column water vapor: Observing horizontal convective rolls

    Science.gov (United States)

    Carbajal Henken, C. K.; Diedrich, H.; Preusker, R.; Fischer, J.

    2015-11-01

    This study presents the first analysis of small-scale convective structures observed in a total column water vapor (TCWV) field obtained from full-resolution Medium Resolution Imaging Spectrometer (MERIS) near-infrared measurements. The high-resolution MERIS TCWV field for a high-pressure event occurring in May over central Europe allows the detection of horizontal convective rolls, due to the observation of parallel bands of alternating low- and high-TCWV values. The bands are aligned parallel to the boundary layer winds obtained from a numerical weather prediction model and radiosonde data. Closer examination further reveals that cloud streets observed in the east extend along bands of maximum TCWV. From a quantitative analysis of the TCWV data, combined with auxiliary data, it is shown that the roll wavelength and aspect ratio can be determined, which are found to be 6.5 km and 4.2, respectively, for this case study.

  12. The stellar mass - size relation for cluster galaxies at z=1 with high angular resolution from the Gemini/GeMS multi-conjugate adaptive optics system

    CERN Document Server

    Sweet, Sarah M; Glazebrook, Karl; Rigaut, Francois; Carrasco, Eleazar R; Brodwin, Mark; Baylliss, Matthew; Stalder, Brian; Abraham, Roberto; McGregor, Peter

    2016-01-01

    We present the stellar mass - size relation for 49 galaxies within the $z$ = 1.067 cluster SPT-CL J0546$-$5345, with FWHM $\\sim$80-120 mas $K_{\\mathrm s}$-band data from the Gemini multi-conjugate adaptive optics system (GeMS/GSAOI). This is the first such measurement in a cluster environment, performed at sub-kpc resolution at rest-frame wavelengths dominated by the light of the underlying old stellar populations. The observed stellar mass - size relation is offset from the local relation by 0.21 dex, corresponding to a size evolution proportional to $(1+z)^{-1.25}$, consistent with the literature. The slope of the stellar mass - size relation $\\beta$ = 0.74 $\\pm$ 0.06, consistent with the local relation. The absence of slope evolution indicates that the amount of size growth is constant with stellar mass. This suggests that galaxies in massive clusters such as SPT-CL J0546$-$5345 grow via processes that increase the size without significant morphological interference, such as minor mergers and/or adiabatic ...

  13. Measurements of the Sunyaev-Zel'dovich Effect in MACS J0647.7+7015 and MACS J1206.2-0847 at High Angular Resolution with MUSTANG

    CERN Document Server

    Young, Alexander H; Romero, Charles; Sayers, Jack; Balestra, Italo; Clarke, Tracy E; Czakon, Nicole; Devlin, Mark; Dicker, Simon R; Ferrari, Chiara; Girardi, Marisa; Golwala, Sunil; Intema, Huib; Korngut, Phillip M; Mason, Brian S; Mercurio, Amata; Nonino, Mario; Reese, Erik D; Rosati, Piero; Sarazin, Craig; Umetsu, Keiichi

    2014-01-01

    We present high resolution (9$^{\\prime \\prime}$) imaging of the Sunyaev-Zel'dovich Effect (SZE) toward two massive galaxy clusters, MACS J0647.7+7015 ($z=0.591$) and MACS J1206.2-0847 ($z=0.439$). We compare these 90 GHz measurements, taken with the MUSTANG receiver on the Green Bank Telescope, with generalized Navarro-Frenk-White (gNFW) models derived from Bolocam 140 GHz SZE data as well as maps of the thermal gas derived from {\\it Chandra} X-ray observations. For MACS J0647.7+7015, we find a gNFW profile with core slope parameter $\\gamma= 0.9$ fits the MUSTANG image with $\\chi^{2}_{red}=1.005$ and probability to exceed (PTE) = 0.34. For MACS J1206.2-0847, we find $\\gamma=0.7$, $\\chi^{2}_{red}=0.993$, and PTE = 0.70. In addition, we find a significant ($>$3-$\\sigma$) residual SZE feature in MACS J1206.2-0847 coincident with a group of galaxies identified in VLT data and filamentary structure found in a weak-lensing mass reconstruction. We suggest the detected sub-structure may be the SZE decrement from a lo...

  14. High-resolution NO2 observations from the Airborne Compact Atmospheric Mapper: Retrieval and validation

    Science.gov (United States)

    Lamsal, L. N.; Janz, S. J.; Krotkov, N. A.; Pickering, K. E.; Spurr, R. J. D.; Kowalewski, M. G.; Loughner, C. P.; Crawford, J. H.; Swartz, W. H.; Herman, J. R.

    2017-02-01

    Nitrogen dioxide (NO2) is a short-lived atmospheric pollutant that serves as an air quality indicator and is itself a health concern. The Airborne Compact Atmospheric Mapper (ACAM) was flown on board the NASA UC-12 aircraft during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality Maryland field campaign in July 2011. The instrument collected hyperspectral remote sensing measurements in the 304-910 nm range, allowing daytime observations of several tropospheric pollutants, including nitrogen dioxide (NO2), at an unprecedented spatial resolution of 1.5 × 1.1 km2. Retrievals of slant column abundance are based on the differential optical absorption spectroscopy method. For the air mass factor computations needed to convert these retrievals to vertical column abundance, we include high-resolution information for the surface reflectivity by using bidirectional reflectance distribution function data from the Moderate Resolution Imaging Spectroradiometer. We use high-resolution simulated vertical distributions of NO2 from the Community Multiscale Air Quality and Global Modeling Initiative models to account for the temporal variation in atmospheric NO2 to retrieve middle and lower tropospheric NO2 columns (NO2 below the aircraft). We compare NO2 derived from ACAM measurements with in situ observations from NASA's P-3B research aircraft, total column observations from the ground-based Pandora spectrometers, and tropospheric column observations from the space-based Ozone Monitoring Instrument. The high-resolution ACAM measurements not only give new insights into our understanding of atmospheric composition and chemistry through observation of subsampling variability in typical satellite and model resolutions, but they also provide opportunities for testing algorithm improvements for forthcoming geostationary air quality missions.

  15. Coordinated Observations of X-ray and High-Resolution EUV Active Region Dynamics

    Science.gov (United States)

    Savage, Sabrina; Cirtain, Jonathan; Winebarger, Amy; Kobayashi, Ken; Golub, Leon; Korreck, Kelly

    2013-01-01

    The recently-launched High-resolution Coronal imager (Hi-C) sounding rocket provided the highest resolution images of coronal loops and other small-scale structures in the 193 Angstrom passband to date. With just 5 minutes of observations, the instrument recorded a variety of dynamic coronal events -- including even a small B-class flare. We will present our results comparing these extreme-ultraviolet (EUV) observations with X-ray imaging from Hinode/XRT as well as EUV AIA data to identify sources of hot plasma rooted in the photosphere and track their affect on the overall topology and dynamics of the active region.

  16. HARPO: beam characterization of a TPC for gamma-ray polarimetry and high angular-resolution astronomy in the MeV-GeV range

    CERN Document Server

    Wang, Shaobo; Bruel, Philippe; Frotin, Mickael; Geerebaert, Yannick; Giebels, Berrie; Gros, Philippe; Horan, Deirdre; Louzir, Marc; Poilleux, Patrick; Semeniouk, Igor; Attié, David; Calvet, Denis; Colas, Paul; Delbart, Alain; Sizun, Patrick; Götz, Diego; Amano, Sho; Kotaka, Takuya; Hashimoto, Satoshi; Minamiyama, Yasuhito; Takemoto, Akinori; Yamaguchi, Masashi; Miyamoto, Shuji; Daté, Schin; Ohkuma, Haruo

    2015-01-01

    A time projection chamber (TPC) can be used to measure the polarization of gamma rays with excellent angular precision and sensitivity in the MeV-GeV energy range through the conversion of photons to e+e- pairs. The Hermetic ARgon POlarimeter (HARPO) prototype was built to demonstrate this concept. It was recently tested in the polarized photon beam at the NewSUBARU facility in Japan. We present this data-taking run, which demonstrated the excellent performance of the HARPO TPC.

  17. Effects of galactic disc inclination and resolution on observed GMC properties and Larson's scaling relations

    Science.gov (United States)

    Pan, Hsi-An; Fujimoto, Yusuke; Tasker, Elizabeth J.; Rosolowsky, Erik; Colombo, Dario; Benincasa, Samantha M.; Wadsley, James

    2016-05-01

    With ALMA (Atacama Large Millimeter/submillimeter Array) making it possible to resolve giant molecular clouds (GMCs) in other galaxies, it is becoming necessary to quantify the observational bias on measured GMC properties. Using a hydrodynamical simulation of a barred spiral galaxy, we compared the physical properties of GMCs formed in position-position-position (PPP) space to the observational position-position-velocity (PPV) space. We assessed the effect of disc inclination: face-on (PPVface) and edge-on (PPVedge), and resolution: 1.5 pc versus 24 pc, on GMC properties and the further implications of using Larson's scaling relations for mass-radius and velocity dispersion-radius. The low-resolution PPV data are generated by simulating ALMA Cycle 3 observations using the CASA package. Results show that the median properties do not differ strongly between PPP and PPVface under both resolutions, but PPVedge clouds deviate from these two. The differences become magnified when switching to the lower, but more realistic resolution. The discrepancy can lead to opposite results for the virial parameter's measure of gravitational binding, and therefore the dynamical state of the clouds. The power-law indices for the two Larson's scaling relations decrease going from PPP, PPVedge to PPVface and decrease from high to low resolutions. We conclude that the relations are not entirely driven by the underlying physical origin and therefore have to be used with caution when considering the environmental dependence, dynamical state, and the extragalactic CO-to-H2 conversion factor of GMCs.

  18. First high spatial resolution interferometric observations of solar flares at millimeter wavelengths

    Science.gov (United States)

    Kundu, M. R.; White, S. M.; Gopalswamy, N.; Bieging, J. H.; Hurford, G. J.

    1990-01-01

    The first high spatial resolution interferometric observations of solar flares at millimeter wavelengths, carried out with the Berkeley-Illinois-Maryland Array are presented. The observations were made at 3.3 mm wavelength during the very active periods of March 1989, using one or three baselines with fringe spacings of 2-5 arcsec. The observations represent an improvement of an order of magnitude in both sensitivity and spatial resolution compared with previous solar observations at these wavelengths. It appears that millimeter burst sources are not much smaller than microwave sources. The most intense bursts imply brightness temperatures of over 10 to the 6th K and are due to nonthermal gyrosynchrotron emission or possibly thermal free-free emission. If the emission in the flash phase is predominantly due to gyrosynchrotron emission, thermal gyrosynchrotron models can be ruled out for the radio emission because the flux at millimeter wavelengths is too high.

  19. Low and high resolution protonium spectroscopy at LEAR in ACOL time: Tools for glueball, hybrid and light meson spectroscopy and for measuring the N anti N strong interaction dependence on angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Gastaldi, U.

    1987-02-20

    Low energy resolution protonium spectroscopy with a large acceptance and high granularity X-ray Drift Chamber offers a new physical instrument to study the dependence of p anti p annihilation at rest on angular momentum and to search for glueball, hybrid, multiquark and conventional mesonic states with narrow and also broad width. This tool has been developed at LEAR within the ASTERIX experiment and will be systematically or in part employed in ACOL time by two new experiments concerned with hadron spectroscopy and dynamics of nucleon-antinucleon interactions. High energy resolution protonium spectroscopy is feasible with an improvement by a factor 1000 over pre-ACOL experiments by using beams of p anti p atoms produced in flight inside LEAR (where H/sup -/ ions have to co-rotate with the anti p coast) and going to a detection equipment external to the ring. The limit to the best relative energy resolution attainable is given by the relative momentum dispersion ..delta..p/p of the beams stored in LEAR. The shift and broadening induced by strong interactions on the four sublevels of the 2P level become therefore measurable, and precise measurements on these quantities look feasible for the two sublevels of the 1S ground state. In the second part of this paper we review this approach to high resolution protonium spectroscopy (IDEFIX experiment) and its feasibility aspects. 61 refs., 5 figs., 3 tabs.

  20. Mapping of CO2 at High Spatiotemporal Resolution using Satellite Observations: Global distributions from OCO-2

    Science.gov (United States)

    Hammerling, Dorit M.; Michalak, Anna M.; Kawa, S. Randolph

    2012-01-01

    Satellite observations of CO2 offer new opportunities to improve our understanding of the global carbon cycle. Using such observations to infer global maps of atmospheric CO2 and their associated uncertainties can provide key information about the distribution and dynamic behavior of CO2, through comparison to atmospheric CO2 distributions predicted from biospheric, oceanic, or fossil fuel flux emissions estimates coupled with atmospheric transport models. Ideally, these maps should be at temporal resolutions that are short enough to represent and capture the synoptic dynamics of atmospheric CO2. This study presents a geostatistical method that accomplishes this goal. The method can extract information about the spatial covariance structure of the CO2 field from the available CO2 retrievals, yields full coverage (Level 3) maps at high spatial resolutions, and provides estimates of the uncertainties associated with these maps. The method does not require information about CO2 fluxes or atmospheric transport, such that the Level 3 maps are informed entirely by available retrievals. The approach is assessed by investigating its performance using synthetic OCO-2 data generated from the PCTM/ GEOS-4/CASA-GFED model, for time periods ranging from 1 to 16 days and a target spatial resolution of 1deg latitude x 1.25deg longitude. Results show that global CO2 fields from OCO-2 observations can be predicted well at surprisingly high temporal resolutions. Even one-day Level 3 maps reproduce the large-scale features of the atmospheric CO2 distribution, and yield realistic uncertainty bounds. Temporal resolutions of two to four days result in the best performance for a wide range of investigated scenarios, providing maps at an order of magnitude higher temporal resolution relative to the monthly or seasonal Level 3 maps typically reported in the literature.

  1. Direct Observation of Cosmic Strings Via Their Strong Gravitational Lensing Effect. 1. Predictions for High Resolution Imaging Surveys

    Energy Technology Data Exchange (ETDEWEB)

    Gasparini, Maria Alice; Marshall, Phil; Treu, Tommaso; /UC, Santa Barbara; Morganson, Eric; /KIPAC, Menlo Park; Dubath, Florian; /Santa Barbara, KITP

    2007-11-14

    We use current theoretical estimates for the density of long cosmic strings to predict the number of strong gravitational lensing events in astronomical imaging surveys as a function of angular resolution and survey area. We show that angular resolution is the single most important factor, and that interesting limits on the dimensionless string tension G{mu}/c{sup 2} can be obtained by existing and planned surveys. At the resolution of the Hubble Space Telescope (0'.14), it is sufficient to survey of order a square degree -- well within reach of the current HST archive -- to probe the regime G{mu}/c{sup 2} {approx} 10{sup -8}. If lensing by cosmic strings is not detected, such a survey would improve the limit on the string tension by an order of magnitude on that available from the cosmic microwave background. At the resolution (0'.028) attainable with the next generation of large ground based instruments, both in the radio and the infra-red with adaptive optics, surveying a sky area of order ten square degrees will allow us to probe the G{mu}/c{sup 2} {approx} 10{sup -9} regime. These limits will not be improved significantly by increasing the solid angle of the survey.

  2. Why AGN studies need higher resolution

    Science.gov (United States)

    Rees, M. J.

    2001-01-01

    To resolve many cosmic phenomena -- both galactic and extragalactic -- requires angular resolutions in the sub-arc-second range (and indeed down to milliseconds or even microseconds). Some examples will be given. This introductory talk will emphasise some key problems that cannot be solved without ultra-high-resolution data, and the complementarity of observations in different wavebands.

  3. Effects of Galactic Disc Inclination and Resolution on Observed GMC Properties and Larson's Scaling Relations

    CERN Document Server

    Pan, Hsi-An; Tasker, Elizabeth J; Rosolowsky, Erik; Colombo, Dario; Benincasa, Samantha M; Wadsley, James

    2016-01-01

    With ALMA making it possible to resolve giant molecular clouds (GMCs) in other galaxies, it is becoming necessary to quantify the observational bias on measured GMC properties. Using a hydrodynamical simulation of a barred spiral galaxy, we compared the physical properties of GMCs formed in position-position-position space (PPP) to the observational position-position-velocity space (PPV). We assessed the effect of disc inclination: face-on (PPV_face) and edge-on (PPV_edge), and resolution: 1.5 pc versus 24 pc, on GMC properties and the further implications of using Larson's scaling relations for mass-radius and velocity dispersion-radius. The low-resolution PPV data are generated by simulating ALMA Cycle 3 observations using the CASA package. Results show that the median properties do not differ strongly between PPP and PPV_face under both resolutions, but PPV_edge clouds deviate from these two. The differences become magnified when switching to the lower, but more realistic resolution. The discrepancy can le...

  4. High resolution earth observation satellites and services in the next decade a European perspective

    Science.gov (United States)

    Schreier, Gunter; Dech, Stefan

    2005-07-01

    Projects to use very high resolution optical satellite sensor data started in the late 90s and are believed to be the major driver for the commercialisation of earth observation. The global political security situation and updated legislative frameworks created new opportunities for high resolution, dual use satellite systems. In addition to new optical sensors, very high resolution synthetic aperture radars will become in the next few years an important component in the imaging satellite fleet. The paper will review the development in this domain so far, and give perspectives on future emerging markets and opportunities. With dual-use satellite initiatives and new political frameworks agreed between the European Commission and the European Space Agency (ESA), the European market becomes very attractive for both service suppliers and customers. The political focus on "Global Monitoring for Environment and Security" (GMES) and the "European Defence and Security Policy" drive and amplify this demand which ranges from low resolution climate monitoring to very high resolution reconnaissance tasks. In order to create an operational and sustainable GMES in Europe by 2007, the European infrastructure need to be adapted and extended. This includes the ESA SENTINEL and OXYGEN programmes, aiming for a fleet of earth observation satellites and an open and operational earth observation ground segment. The harmonisation of national and regional geographic information is driven by the European Commission's INSPIRE programme. The necessary satellite capacity to complement existing systems in the delivery of space based data required for GMES is currently under definition. Embedded in a market with global competition and in the global political framework of a Global Earth Observation System of Systems, European companies, agencies and research institutions are now contributing to this joint undertaking. The paper addresses the chances, risks and options for the future.

  5. Towards high resolution mapping of 3-D mesoscale dynamics from observations

    Directory of Open Access Journals (Sweden)

    B. Buongiorno Nardelli

    2012-10-01

    Full Text Available The MyOcean R&D project MESCLA (MEsoSCaLe dynamical Analysis through combined model, satellite and in situ data was devoted to the high resolution 3-D retrieval of tracer and velocity fields in the oceans, based on the combination of in situ and satellite observations and quasi-geostrophic dynamical models. The retrieval techniques were also tested and compared with the output of a primitive equation model, with particular attention to the accuracy of the vertical velocity field as estimated through the Q vector formulation of the omega equation. The project focused on a test case, covering the region where the Gulf Stream separates from the US East Coast. This work demonstrated that innovative methods for the high resolution mapping of 3-D mesoscale dynamics from observations can be used to build the next generations of operational observation-based products.

  6. High Resolution $\\lambda$=1mm CARMA Observations of Large Molecules in Orion-KL

    CERN Document Server

    Friedel, D N

    2007-01-01

    We present high resolution, Combined Array for Research in Millimeter-Wave Astronomy (CARMA), $\\lambda$=1mm observations of several molecular species toward Orion-KL. These are the highest spatial and spectral resolution 1mm observations of these molecules to date. Our observations show that ethyl cyanide [C$_2$H$_5$CN] and vinyl cyanide [C$_2$H$_3$CN] originate from multiple cores near the Orion hot core and IRc7. Additionally we show that dimethyl ether [(CH$_3$)$_2$O] and methyl formate [HCOOCH$_3$] originate from IRc5 and IRc6 and that acetone [(CH$_3$)$_2$CO] originates only from areas where both N-bearing and O-bearing species are present.

  7. High Resolution $\\lambda$ = 2.7 mm Observations of L1551 IRS5 A Protobinary System?

    CERN Document Server

    Looney, L W; Welch, W J; Looney, Leslie W.; Mundy, Lee G.

    1997-01-01

    We present sub-arcsecond resolution imaging of the $\\lambda$ = 2.7 mm continuum emission from the young, embedded system L1551 IRS5 using the nine-element, high-resolution configuration of the BIMA array. The observed emission arises from two compact sources separated by $0\\farcs$35, coinciding with the two sources seen at $\\lambda$ = 2 cm and $\\lambda$ = 1.3 cm. When the high resolution data is combined with data from two compact configurations, L1551 IRS5 is argued to consist of a protobinary system separated by $\\sim$50 AU with individual circumstellar disks, a circumbinary structure, and a large-scale envelope. The characteristic masses of the components are: 0.024 M$_{\\sun}$ for the northern circumstellar disk, 0.009 M$_{\\sun}$ for the southern circumstellar disk, 0.04 M$_{\\sun}$ for the circumbinary material, and 0.28 M$_{\\sun}$ for the envelope.

  8. Validation of a global hydrodynamic flood inundation model against high resolution observation data of urban flooding

    Science.gov (United States)

    Bates, Paul; Sampson, Chris; Smith, Andy; Neal, Jeff

    2015-04-01

    In this work we present further validation results for a hyper-resolution global flood inundation model. We use a true hydrodynamic model that uses highly efficient numerical algorithms (LISFLOOD-FP) to simulate flood inundation at ~1km resolution globally and then use downscaling algorithms to determine flood extent and water depth at 3 seconds of arc spatial resolution (~90m at the equator). The global model has ~150 million cells and requires ~180 hours of CPU time for a 10 year simulation period. Terrain data are taken from a custom version of the SRTM data set that has been processed specifically for hydrodynamic modelling. Return periods of flood flows along the entire global river network are determined using: (1) empirical relationships between catchment characteristics and index flood magnitude in different hydroclimatic zones derived from global runoff data; and (2) an index flood growth curve, also empirically derived. Bankful return period flow is then used to set channel width and depth, and flood defence impacts are modelled using empirical relationships between GDP, urbanization and defence standard of protection. The results of these simulations are global flood hazard maps for a number of different return period events from 1 in 5 to 1 in 1000 years. This method has already been show to compare well to return period flood hazard maps derived from models built with high resolution and accuracy local data (Sampson et al., submitted), yet the output from the global flood model has not yet been compared to real flood observations. Whilst the spatial resolution of the global model is high given the size of the model domain, ~1km resolution is still coarse compared to the models typically used to simulate urban flooding and the data typically used to validate these (~25m or less). Comparison of the global model to real-world observations or urban flooding therefore represents an exceptionally stringent test of model skill. In this paper we therefore

  9. Milne-Eddington inversions of high resolution observations of the quiet Sun

    CERN Document Server

    Suárez, D Orozco; Vögler, A; Iniesta, J C Del Toro

    2010-01-01

    The physical conditions of the solar photosphere change on very small spatial scales both horizontally and vertically. Such a complexity may pose a serious obstacle to the accurate determination of solar magnetic fields. We examine the applicability of Milne-Eddington (ME) inversions to high spatial resolution observations of the quiet Sun. Our aim is to understand the connection between the ME inferences and the actual stratifications of the atmospheric parameters. We use magnetoconvection simulations of the solar surface to synthesize asymmetric Stokes profiles such as those observed in the quiet Sun. We then invert the profiles with the ME approximation. We perform an empirical analysis of the heights of formation of ME measurements and analyze the uncertainties brought about by the ME approximation. We also investigate the quality of the fits and their relationship with the model stratifications. The atmospheric parameters derived from ME inversions of high-spatial resolution profiles are reasonably accur...

  10. Supernova Remnant 1987A: High Resolution Images and Spectrum from Chandra Observations

    CERN Document Server

    Park, S; Burrows, D N; Racusin, J L; McCray, R; Borkowski, K J; Park, Sangwook; Zhekov, Svetozar A.; Burrows, David N.; Racusin, Judith L.; Cray, Richard Mc; Borkowski, Kazimierz J.

    2005-01-01

    We report on the morphological and spectral evolution of SNR 1987A from the monitoring observations with the Chandra/ACIS. As of 2005, the X-ray-bright lobes are continuously brightening and expanding all around the ring. The softening of the overall X-ray spectrum also continues. The X-ray lightcurve is particularly remarkable: i.e., the recent soft X-ray flux increase rate is significantly deviating from the model which successfully fits the earlier data, indicating even faster flux increase rate since early 2004 (day ~6200). We also report results from high resolution spectral analysis with deep Chandra/LETG observations. The high resolution X-ray line emission features unambiguously reveal that the X-ray emission of SNR 1987A is originating primarily from a "disk" along the inner ring rather than from a spherical shell. We present the ionization structures, elemental abundances, and the shock velocities of the X-ray emitting plasma.

  11. High spatial resolution observations of solar flares at 3.3 mm wavelength

    Science.gov (United States)

    Kundu, M. R.; White, S. M.; Welch, W. J.; Bieging, J. H.

    1991-01-01

    The first high-spatial-resolution interferometric observations of solar flares at millimeter wavelengths are presented. They are of high sensitivity, and events ranging from subflares to X-class flares were detected. One to three baselines with fringe spacings of 2 to 5 arcsec were available, which demonstrated that generally source sizes were in excess of 2 arcsec, but in some events the sources may be about 1 arcsec.

  12. A multi-transition study of molecules toward NGC 1068 based on high-resolution imaging observations with ALMA

    Science.gov (United States)

    Nakajima, Taku; Takano, Shuro; Kohno, Kotaro; Harada, Nanase; Herbst, Eric; Tamura, Yoichi; Izumi, Takuma; Taniguchi, Akio; Tosaki, Tomoka

    2015-02-01

    We present 0.8-mm band molecular images and spectra obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) toward one of the nearest galaxies with an active galactic nucleus (AGN), NGC 1068. Distributions of CO isotopic species (13CO and C18O) J = 3-2, CN N = 3-2, and CS J = 7-6 are observed toward the circumnuclear disk (CND) and a part of the starburst ring with an angular resolution of ˜ 1.3" × 1.2". The physical properties of these molecules and shock-related molecules, such as HNCO, CH3CN, SO, and CH3OH, detected in the 3-mm band were estimated using rotation diagrams under the assumption of local thermodynamic equilibrium. The rotational temperatures of the CO isotopic species and the shock-related molecules in the CND are, respectively, 14-22 K and upper limits of 20-40 K. Although the column densities of the CO isotopic species in the CND are only from one-fifth to one-third of that in the starburst ring, those of the shock-related molecules are enhanced by a factor of 3-10 in the CND. We also discuss the chemistry of each species, and compare the fractional abundances in the CND and starburst ring with those of Galactic sources such as cold cores, hot cores, and shocked molecular clouds in order to study the overall characteristics. We find that the abundances of shock-related molecules are more similar to abundances in hot cores and/or shocked clouds than to cold cores. The CND hosts relatively complex molecules, which are often associated with shocked molecular clouds or hot cores. Because a high X-ray flux can dissociate these molecules, they must also reside in regions shielded from X-rays.

  13. High resolution 3-D temperature and salinity fields derived from in situ and satellite observations

    Directory of Open Access Journals (Sweden)

    S. Guinehut

    2012-10-01

    Full Text Available This paper describes an observation-based approach that efficiently combines the main components of the global ocean observing system using statistical methods. Accurate but sparse in situ temperature and salinity profiles (mainly from Argo for the last 10 yr are merged with the lower accuracy but high-resolution synthetic data derived from satellite altimeter and sea surface temperature observations to provide global 3-D temperature and salinity fields at high temporal and spatial resolution. The first step of the method consists in deriving synthetic temperature fields from altimeter and sea surface temperature observations, and salinity fields from altimeter observations, through multiple/simple linear regression methods. The second step of the method consists in combining the synthetic fields with in situ temperature and salinity profiles using an optimal interpolation method. Results show the revolutionary nature of the Argo observing system. Argo observations now allow a global description of the statistical relationships that exist between surface and subsurface fields needed for step 1 of the method, and can constrain the large-scale temperature and mainly salinity fields during step 2 of the method. Compared to the use of climatological estimates, results indicate that up to 50% of the variance of the temperature fields can be reconstructed from altimeter and sea surface temperature observations and a statistical method. For salinity, only about 20 to 30% of the signal can be reconstructed from altimeter observations, making the in situ observing system essential for salinity estimates. The in situ observations (step 2 of the method further reduce the differences between the gridded products and the observations by up to 20% for the temperature field in the mixed layer, and the main contribution is for salinity and the near surface layer with an improvement up to 30%. Compared to estimates derived using in situ observations only, the

  14. Earthshine observations at high spectral resolution: Exploring and detecting metal lines in the Earth's upper atmosphere

    CERN Document Server

    González-Merino, B; Motalebi, F; Montañés-Rodríguez, P; Kissler-Patig, M

    2013-01-01

    Observations of the Earth as a planet using the earthshine technique (i.e. looking at the light reflected from the darkside of the Moon), have been used for climate and astrobiology studies. They provide information about the planetary albedo, a fundamental parameter of the Earth's energy balance. Here we present for the first time, observations of the earthshine taken at high spectral resolution. The high spectral resolution was chosen in order to investigate the possibility of detecting metallic layers in the Earth's atmosphere of geological or meteoritic origin. The SARG echelle spectrograph at the Telescopio Nazionale Galileo in La Palma was used to acquire the earthshine data. Observations were carried out on several nights in February 2011, with the spectral resolution set at 29,000, covering a spectral range from the near-ultraviolet (360 nm) to near-infrared (1011.9 nm). While we find evidence for the detection of a Na layer in the earthshine, other atomic species are not detected, perhaps due to the ...

  15. High spatial resolution FeXII observations of solar active region

    CERN Document Server

    Testa, Paola; Hansteen, Viggo

    2016-01-01

    We use UV spectral observations of active regions with the Interface Region Imaging Spectrograph (IRIS) to investigate the properties of the coronal FeXII 1349.4A emission at unprecedented high spatial resolution (~0.33"). We find that by using appropriate observational strategies (i.e., long exposures, lossless compression), FeXII emission can be studied with IRIS at high spatial and spectral resolution, at least for high density plasma (e.g., post-flare loops, and active region moss). We find that upper transition region (moss) FeXII emission shows very small average Doppler redshifts (v_Dop ~3 km/s), as well as modest non-thermal velocities (with an average ~24 km/s, and the peak of the distribution at ~15 km/s). The observed distribution of Doppler shifts appears to be compatible with advanced 3D radiative MHD simulations in which impulsive heating is concentrated at the transition region footpoints of a hot corona. While the non-thermal broadening of FeXII 1349.4A peaks at similar values as lower resolut...

  16. High Resolution Rapid Response observations of compact radio sources with the Ceduna Hobart Interferometer (CHI)

    CERN Document Server

    Blanchard, Jay M; Ojha, Roopesh; Kadler, Matthias; Dickey, John M; Edwards, Philip G

    2012-01-01

    Context. Frequent, simultaneous observations across the electromagnetic spectrum are essential to the study of a range of astrophysical phenomena including Active Galactic Nuclei. A key tool of such studies is the ability to observe an object when it flares i.e. exhibits a rapid and significant increase in its flux density. Aims. We describe the specific observational procedures and the calibration techniques that have been developed and tested to create a single baseline radio interferometer that can rapidly observe a flaring object. This is the only facility that is dedicated to rapid high resolution radio observations of an object south of -30 degrees declination. An immediate application is to provide rapid contemporaneous radio coverage of AGN flaring at {\\gamma}-ray frequencies detected by the Fermi Gamma-ray Space Telescope. Methods. A single baseline interferometer was formed with radio telescopes in Hobart, Tasmania and Ceduna, South Australia. A software correlator was set up at the University of Ta...

  17. High Resolution 3-D temperature and salinity fields derived from in situ and satellite observations

    Directory of Open Access Journals (Sweden)

    S. Guinehut

    2012-03-01

    Full Text Available This paper describes an observation-based approach that combines efficiently the main components of the global ocean observing system using statistical methods. Accurate but sparse in situ temperature and salinity profiles (mainly from Argo for the last 10 years are merged with the lower accuracy but high-resolution synthetic data derived from altimeter and sea surface temperature satellite observations to provide global 3-D temperature and salinity fields at high temporal and spatial resolution. The first step of the method consists in deriving synthetic temperature fields from altimeter and sea surface temperature observations and salinity fields from altimeter observations through multiple/simple linear regression methods. The second step of the method consists in combining the synthetic fields with in situ temperature and salinity profiles using an optimal interpolation method. Results show the revolution of the Argo observing system. Argo observations now allow a global description of the statistical relationships that exist between surface and subsurface fields needed for step 1 of the method and can constrain the large-scale temperature and mainly salinity fields during step 2 of the method. Compared to the use of climatological estimates, results indicate that up to 50 % of the variance of the temperature fields can be reconstructed from altimeter and sea surface temperature observations and a statistical method. For salinity, only about 20 to 30 % of the signal can be reconstructed from altimeter observations, making the in situ observing system mandatory for salinity estimates. The in situ observations (step 2 of the method reduce additionally the error by up to 20 % for the temperature field in the mixed layer and the main contribution is for salinity and the near surface layer with an improvement up to 30 %. Compared to estimates derived using in situ observations only, the merged fields provide a better reconstruction of the high

  18. Daniel K. Inouye Solar Telescope: High-resolution observing of the dynamic Sun

    Science.gov (United States)

    Tritschler, A.; Rimmele, T. R.; Berukoff, S.; Casini, R.; Kuhn, J. R.; Lin, H.; Rast, M. P.; McMullin, J. P.; Schmidt, W.; Wöger, F.; DKIST Team

    2016-11-01

    The 4-m aperture Daniel K. Inouye Solar Telescope (DKIST) formerly known as the Advanced Technology Solar Telescope (ATST) is currently under construction on Haleakalā (Maui, Hawai'i) projected to start operations in 2019. At the time of completion, DKIST will be the largest ground-based solar telescope providing unprecedented resolution and photon collecting power. The DKIST will be equipped with a set of first-light facility-class instruments offering unique imaging, spectroscopic and spectropolarimetric observing opportunities covering the visible to infrared wavelength range. This first-light instrumentation suite will include: a Visible Broadband Imager (VBI) for high-spatial and -temporal resolution imaging of the solar atmosphere; a Visible Spectro-Polarimeter (ViSP) for sensitive and accurate multi-line spectropolarimetry; a Fabry-Pérot based Visible Tunable Filter (VTF) for high-spatial resolution spectropolarimetry; a fiber-fed Diffraction-Limited Near Infra-Red Spectro-Polarimeter (DL-NIRSP) for two-dimensional high-spatial resolution spectropolarimetry (simultaneous spatial and spectral information); and a Cryogenic Near Infra-Red Spectro-Polarimeter (Cryo-NIRSP) for coronal magnetic field measurements and on-disk observations of, e.g., the CO lines at 4.7 μm. We will provide an overview of the DKIST's unique capabilities with strong focus on the first-light instrumentation suite, highlight some of the additional properties supporting observations of transient and dynamic solar phenomena, and touch on some operational strategies and the DKIST critical science plan.

  19. Low-Resolution Near-infrared Stellar Spectra Observed by the Cosmic Infrared Background Experiment (CIBER)

    Science.gov (United States)

    Kim, Min Gyu; Lee, Hyung Mok; Arai, Toshiaki; Bock, James; Cooray, Asantha; Jeong, Woong-Seob; Kim, Seong Jin; Korngut, Phillip; Lanz, Alicia; Lee, Dae Hee; Lee, Myung Gyoon; Matsumoto, Toshio; Matsuura, Shuji; Nam, Uk Won; Onishi, Yosuke; Shirahata, Mai; Smidt, Joseph; Tsumura, Kohji; Yamamura, Issei; Zemcov, Michael

    2017-02-01

    We present near-infrared (0.8–1.8 μm) spectra of 105 bright ({m}J < 10) stars observed with the low-resolution spectrometer on the rocket-borne Cosmic Infrared Background Experiment. As our observations are performed above the Earth's atmosphere, our spectra are free from telluric contamination, which makes them a unique resource for near-infrared spectral calibration. Two-Micron All-Sky Survey photometry information is used to identify cross-matched stars after reduction and extraction of the spectra. We identify the spectral types of the observed stars by comparing them with spectral templates from the Infrared Telescope Facility library. All the observed spectra are consistent with late F to M stellar spectral types, and we identify various infrared absorption lines.

  20. A High Spectral Resolution Observation of the Soft X-ray Diffuse Background with Thermal Detectors

    CERN Document Server

    McCammon, D; Apodaca, E; Tiest, W B; Cui, W; Deiker, S W; Galeazzi, M; Juda, M; Lesser, A; Mihara, T; Morgenthaler, J P; Sanders, W T; Zhang, J; Figueroa-Feliciano, E; Kelley, R L; Moseley, S H; Mushotzky, R F; Porter, F S; Stahle, C K; Szymkowiak, A E

    2002-01-01

    A high spectral resolution observation of the diffuse X-ray background in the 60 - 1000 eV energy range has been made using an array of thirty-six 1 mm^2 micro-calorimeters flown on a sounding rocket. Detector energy resolution ranged from 5-12 eV FWHM, and a composite spectrum of ~ 1 steradian of the background centered at l = 90, b = +60 was obtained with a net resolution of ~ 9 eV. The target area includes bright 1/4 keV regions, but avoids Loop I and the North Polar Spur. Lines of C VI, O VII, and O VIII are clearly detected with intensities of 5.4 +/- 2.3, 4.8 +/- 0.8, and 1.6 +/- 0.4 photons cm^-2 s^-1 sr^-1, respectively. The oxygen lines alone account for a majority of the diffuse background observed in the ROSAT R4 band that is not due to resolved extragalactic discrete sources. We also have a positive detection of the Fe-M line complex near 70 eV at an intensity consistent with previous upper limits that indicate substantial gas phase depletion of iron. We include a detailed description of the instr...

  1. Angular Momentum Constraints on GMC formation in M33

    Science.gov (United States)

    Rosolowsky, E.; Engargiola, G.; Plambeck, R.; Blitz, L.

    2001-12-01

    We present the results of the complete CO 12CO(1-> 0) survey of the molecular gas in M33. These observations represent the first survey of all of the GMCs in a spiral galaxy; CO surveys of the Milky Way are too severely blended in some regions to separate the GMCs from one another. These observations show that individual molecular clouds share many properties with those found in the Milky Way although the most massive GMC in M33 has a mass of only 7x 105 Msun and is not associated with an Hii region. Moreover, the specific angular momentum of the GMCs is more than an order of magnitude smaller than expected for basic formation scenarios. The observational campaign consists of two parts: 1) a complete survey of the star forming disk which represents a complete census of GMCs down to the Taurus cloud mass at low spatial resolution and high surface brightness sensitivity and 2) high resolution follow-up observations which spatially resolve the molecular clouds providing information on rotation properties, virial masses, and morphology. From the latter, we estimate the angular momentum imparted through galactic shear by Jeans collapse, the Toomre instability and the Parker instability, all of which impart much more angular momentum to the clouds than is observed. We propose the magnetic fields that thread the molecular clouds and connect to the diffuse interstellar medium brake the spin-up of the progenitor gas, suggesting that the formation of GMCs is a magnetohydrodynamic process.

  2. Autonomous, high-resolution observations of particle flux in the oligotrophic ocean

    Directory of Open Access Journals (Sweden)

    M. L. Estapa

    2013-08-01

    Full Text Available Observational gaps limit our understanding of particle flux attenuation through the upper mesopelagic because available measurements (sediment traps and radiochemical tracers have limited temporal resolution, are labor-intensive, and require ship support. Here, we conceptually evaluate an autonomous, optical proxy-based method for high-resolution observations of particle flux. We present four continuous records of particle flux collected with autonomous profiling floats in the western Sargasso Sea and the subtropical North Pacific, as well as one shorter record of depth-resolved particle flux near the Bermuda Atlantic Time-series Study (BATS and Oceanic Flux Program (OFP sites. These observations illustrate strong variability in particle flux over very short (~1-day timescales, but at longer timescales they reflect patterns of variability previously recorded during sediment trap time series. While particle flux attenuation at BATS/OFP agreed with the canonical power-law model when observations were averaged over a month, flux attenuation was highly variable on timescales of 1–3 days. Particle fluxes at different depths were decoupled from one another and from particle concentrations and chlorophyll fluorescence in the immediately overlying surface water, consistent with horizontal advection of settling particles. We finally present an approach for calibrating this optical proxy in units of carbon flux, discuss in detail the related, inherent physical and optical assumptions, and look forward toward the requirements for the quantitative application of this method in highly time-resolved studies of particle export and flux attenuation.

  3. Autonomous, high-resolution observations of particle flux in the oligotrophic ocean

    Directory of Open Access Journals (Sweden)

    M. L. Estapa

    2013-01-01

    Full Text Available Observational gaps limit our understanding of particle flux attenuation through the upper mesopelagic because available measurements (sediment traps and radiochemical tracers have limited temporal resolution, are labor-intensive, and require ship support. Here, we conceptually evaluate an autonomous, optical proxy-based method for high-resolution observations of particle flux. We present four continuous records of particle flux collected with autonomous, profiling floats in the western Sargasso Sea and the subtropical North Pacific, as well as one shorter record of depth-resolved particle flux near the Bermuda Atlantic Timeseries Study (BATS and Oceanic Flux Program (OFP sites. These observations illustrate strong variability in particle flux over very short (~1 day timescales, but at longer timescales they reflect patterns of variability previously recorded during sediment trap timeseries. While particle flux attenuation at BATS/OFP agreed with the canonical power-law model when observations were averaged over a month, flux attenuation was highly variable on timescales of 1–3 days. Particle fluxes at different depths were decoupled from one another and from particle concentrations and chlorophyll fluorescence in the immediately-overlying surface water, consistent with horizontal advection of settling particles. We finally present an approach for calibrating this optical proxy in units of carbon flux, discuss in detail the related, inherent physical and optical assumptions, and look forward toward the requirements for the quantitative application of this method in highly time-resolved studies of particle export and flux attenuation.

  4. Mean angular diameters, distances and pulsation modes of the classical Cepheids FF Aql and T Vul - CHARA/FLUOR near-infrared interferometric observations

    CERN Document Server

    Gallenne, A; Mérand, A; McAlister, H; Brummelaar, T ten; Foresto, V Coudé du; Sturmann, J; Sturmann, L; Turner, N; Farrington, C; Goldfinger, P J

    2012-01-01

    We report the first angular diameter measurements of two classical Cepheids, FF Aql and T Vul, that we have obtained with the FLUOR instrument installed at the CHARA interferometric array. We obtain average limb-darkened angular diameters of \\theta_LD = 0.878 +/- 0.013 mas and \\theta_LD = 0.629 +/- 0.013 mas, respectively for FF Aql and T Vul. Combining these angular diameters with the HST-FGS trigonometric parallaxes leads to linear radii R = 33.6 +/- 2.2 Rsol and R = 35.6 +/- 4.4 Rsol, respectively. The comparison with empirical and theoretical Period-Radius relations leads to the conclusion that these Cepheids are pulsating in their fundamental mode. The knowledge of the pulsation mode is of prime importance to calibrate the Period-Luminosity relation with a uniform sample of fundamental mode Cepheids.

  5. High mass resolution, high angular acceptance time-of-flight mass spectroscopy for planetary missions under the Planetary Instrument Definition and Development Program (PIDDP)

    Science.gov (United States)

    Young, David T.

    1991-01-01

    This final report covers three years and several phases of work in which instrumentation for the Planetary Instrument Definition and Development Program (PIDDP) were successfully developed. There were two main thrusts to this research: (1) to develop and test methods for electrostatically scanning detector field-of-views, and (2) to improve the mass resolution of plasma mass spectrometers to M/delta M approximately 25, their field-of-view (FOV) to 360 degrees, and their E-range to cover approximately 1 eV to 50 keV. Prototypes of two different approaches to electrostatic scanning were built and tested. The Isochronous time-of-flight (TOF) and the linear electric field 3D TOF devices were examined.

  6. Investigation of the Chromosphere-Corona Interface with the Upgraded Very high angular Resolution ULtraviolet Telescope (VAULT2.0) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a three-year effort to upgrade our existing sub-arcsecond Lyman-alpha telescope payload to improve the observing cadence by a factor of 2, increase the...

  7. Four-dimensional data assimilation with optimized viscosity using High Resolution Doppler Lidar observations

    Science.gov (United States)

    Chai, Tianfeng; Lin, Ching-Long

    2001-11-01

    We present a four-dimensional variational data assimilation (4D-Var) technique with optimized eddy viscosity for the retrieval of the detailed atmospheric boundary-layer structures from High-Resolution Doppler Lidar (HRDL) radial velocity observations. The 4D-Var is based on the calculus of variations and optimal control theory to recover complete and dynamically consistent data set by minimizing the difference between limited observations and corresponding model predictions. To reflect the nature of the atmospheric boundary layer under various stability conditions, eddy viscosity is treated as part of control variables to be optimized in the 4D-Var model. The mathematical formulation for optimizing eddy viscosity is presented. The model is validated by conducting numerical experiments that utilize synthetic observations. We then apply the 4D-Var to the HRDL data measured under convective and stable conditions.

  8. High resolution SZ observations at the IRAM 30-m telescope with NIKA

    CERN Document Server

    Adam, R; Ade, P; Andrée, P; Beelen, A; Belier, B; Benoît, A; Bideaud, A; Billot, N; Boudou, N; Bourrion, O; Calvo, M; Catalano, A; Coiffard, G; Comis, B; D'Addabbo, A; Désert, F -X; Doyle, S; Goupy, J; Kramer, C; Leclercq, S; Macías-Pérez, J F; Martino, J; Mauskopf, P; Mayet, F; Monfardini, A; Pajot, F; Pascale, E; Perotto, L; Pointecouteau, E; Ponthieu, N; Revéret, V; Rodriguez, L; Ruppin, F; Savini, G; Schuster, K; Sievers, A; Tucker, C; Zylka, R

    2014-01-01

    High resolution observations of the thermal Sunyaev-Zel'dovich (tSZ) effect are necessary to allow the use of clusters of galaxies as a probe for large scale structures at high redshifts. With its high resolution and dual-band capability at millimeter wavelengths, the NIKA camera can play a significant role in this context. NIKA is based on newly developed Kinetic Inductance Detectors (KIDs) and operates at the IRAM 30m telescope, Pico Veleta, Spain. In this paper, we give the status of the NIKA camera, focussing on the KID technology. We then present observations of three galaxy clusters: RX J1347.5-1145 as a demonstrator of the NIKA capabilities and the recent observations of CL J1226.9+3332 (z = 0.89) and MACS J0717.5+3745 (z = 0.55). We also discuss prospects for the final NIKA2 camera, which will have a 6.5 arcminute field of view with about 5000 detectors in two bands at 150 and 260 GHz.

  9. Comet Shoemaker-Levy 9/Jupiter collision observed with a high resolution speckle imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Gravel, D. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    During the week of July 16, 1994, comet Shoemaker-Levy 9, broken into 20 plus pieces by tidal forces on its last orbit, smashed into the planet Jupiter, releasing the explosive energy of 500 thousand megatons. A team of observers from LLNL used the LLNL Speckle Imaging Camera mounted on the University of California`s Lick Observatory 3 Meter Telescope to capture continuous sequences of planet images during the comet encounter. Post processing with the bispectral phase reconstruction algorithm improves the resolution by removing much of the blurring due to atmospheric turbulence. High resolution images of the planet surface showing the aftermath of the impact are probably the best that were obtained from any ground-based telescope. We have been looking at the regions of the fragment impacts to try to discern any dynamic behavior of the spots left on Jupiter`s cloud tops. Such information can lead to conclusions about the nature of the comet and of Jupiter`s atmosphere. So far, the Hubble Space Telescope has observed expanding waves from the G impact whose mechanism is enigmatic since they appear to be too slow to be sound waves and too fast to be gravity waves, given the present knowledge of Jupiter`s atmosphere. Some of our data on the G and L impact region complements the Hubble observations but, so far, is inconclusive about spot dynamics.

  10. High resolution radio observations of nuclear and circumnuclear regions of luminous infrared galaxies (LIRGs)

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, A; Perez-Torres, M A [Instituto de Astrofisica de Andalucia (IAA, CSIC), PO Box 3004, 18080-Granada (Spain); Colina, L [Instituto de Estructura de la Materia - IEM, CSIC, C, Serrano 115, 28005 Madrid (Spain); Torrelles, J M [Instituto de Ciencias del Espacio (ICE, CSIC) and IEEC, Gran Capita 2-4, 08034 Barcelona (Spain)], E-mail: antxon@iaa.es, E-mail: torres@iaa.es, E-mail: colina@damir.iem.csic.es, E-mail: torrelle@ieec.fcr.es

    2008-10-15

    High-resolution radio observations of the nuclear region of Luminous and Ultraluminous Infrared Galaxies (ULIRGs) have shown that its radio structure consists of a compact high surface-brightness central radio source immersed in a diffuse low brightness circumnuclear halo. While the central component could be associated with an AGN or compact star-forming regions where radio supernovae are exploding, it is well known that the circumnuclear regions host bursts of star-formation. The studies of radio supernovae can provide essential information about stellar evolution and CSM/ISM properties in regions hidden by dust at optical and IR wavelengths. In this contribution, we show results from radio interferometric observations from NGC 7469, IRAS 18293-3413 and IRAS 17138-1017 where three extremely bright radio supernovae have been found. High-resolution radio observations of these and other LIRGs would allow us to determine the core-collapse supernova rate in them as well as their star-formation rate.

  11. Electron Temperatures in W51 Complex from High Resolution, Low Frequency Radio Observations

    Indian Academy of Sciences (India)

    P. K. Srivastava; A. Pramesh Rao

    2010-03-01

    W51 is a giant radio complex lying along the tangent to the Sagitarius arm at a distance of about 7 kpc from the Sun, with an extension of about 1° in the sky. It is divided into three components A, B, C where W51A and W51B consist of many compact HII regions while W51C is a supernova remnant. We have made continuum radio observations of these HII regions of the W51 complex at 240, 610, 1060 and 1400 MHz using GMRT with lower resolution (20'' × 15'') at the lowest frequency. The observed spectra of the prominent thermal subcomponents of W51 have been fitted to a free-free emission spectrum and their physical properties like electron temperatures and emission measures have been estimated. The electron temperatures from continuum spectra are found to be lower than the temperatures reported from radio recombination line (RRL) studies of these HII regions indicating the need for a filling factor even at this resolution. Also, the observed brightness at 240 MHz is found to be higher than expected from the best fits suggesting the need for a multicomponent model for the region.

  12. Overview of LBTI: a multipurpose facility for high spatial resolution observations

    Science.gov (United States)

    Hinz, P. M.; Defrère, D.; Skemer, A.; Bailey, V.; Stone, J.; Spalding, E.; Vaz, A.; Pinna, E.; Puglisi, A.; Esposito, S.; Montoya, M.; Downey, E.; Leisenring, J.; Durney, O.; Hoffmann, W.; Hill, J.; Millan-Gabet, R.; Mennesson, B.; Danchi, W.; Morzinski, K.; Grenz, P.; Skrutskie, M.; Ertel, S.

    2016-08-01

    The Large Binocular Telescope Interferometer (LBTI) is a high spatial resolution instrument developed for coherent imaging and nulling interferometry using the 14.4 m baseline of the 2×8.4 m LBT. The unique telescope design, comprising of the dual apertures on a common elevation-azimuth mount, enables a broad use of observing modes. The full system is comprised of dual adaptive optics systems, a near-infrared phasing camera, a 1-5 μm camera (called LMIRCam), and an 8-13 μm camera (called NOMIC). The key program for LBTI is the Hunt for Observable Signatures of Terrestrial planetary Systems (HOSTS), a survey using nulling interferometry to constrain the typical brightness from exozodiacal dust around nearby stars. Additional observations focus on the detection and characterization of giant planets in the thermal infrared, high spatial resolution imaging of complex scenes such as Jupiter's moon, Io, planets forming in transition disks, and the structure of active Galactic Nuclei (AGN). Several instrumental upgrades are currently underway to improve and expand the capabilities of LBTI. These include: Improving the performance and limiting magnitude of the parallel adaptive optics systems; quadrupling the field of view of LMIRcam (increasing to 20"x20"); adding an integral field spectrometry mode; and implementing a new algorithm for path length correction that accounts for dispersion due to atmospheric water vapor. We present the current architecture and performance of LBTI, as well as an overview of the upgrades.

  13. Airborne high spectral resolution lidar observation of pollution aerosol during EUCAARI-LONGREX

    Directory of Open Access Journals (Sweden)

    S. Groß

    2012-10-01

    Full Text Available Airborne high spectral resolution lidar observations over Europe during the EUCAARI field experiment in May 2008 are analysed with respect to spatial distribution and optical properties of continental pollution aerosol. Continental aerosol is characterized by its depolarisation and lidar ratio. Mean values of 6%±1% for the particle linear depolarisation ratio, and 56 sr±6 sr for the lidar ratio were found for pollution aerosol. Both, lidar ratio and depolarisation ratio at 532 nm show virtually no variations for all analysed days during the measurement campaign.

  14. Crack tip shielding observed with high-resolution transmission electron microscopy.

    Science.gov (United States)

    Adhika, Damar Rastri; Tanaka, Masaki; Daio, Takeshi; Higashida, Kenji

    2015-10-01

    The dislocation shielding field at a crack tip was experimentally proven at the atomic scale by measuring the local strain in front of the crack tip using high-resolution transmission electron microscopy (HRTEM) and geometric phase analysis (GPA). Single crystalline (110) silicon wafers were employed. Cracks were introduced using a Vickers indenter at room temperature. The crack tip region was observed using HRTEM followed by strain measurements using GPA. The measured strain field at the crack tip was compressive owing to dislocation shielding, which is in good agreement with the strain field calculated from elastic theory.

  15. High resolution Dopplerimetry of correlated angular and quantum state-resolved CO(2) scattering dynamics at the gas-liquid interface.

    Science.gov (United States)

    Perkins, Bradford G; Nesbitt, David J

    2010-11-14

    Full three dimensional (3D) translational distributions for quantum state-resolved scattering dynamics at the gas-liquid interface are presented for experimental and theoretical studies of CO(2) + perfluorinated surfaces. Experimentally, high resolution absorption profiles are measured as a function of incident (θ(inc)) and scattering (θ(scat)) angles for CO(2) that has been scattered from a 300 K perfluorinated polyether surface (PFPE) with an incident energy of E(inc) = 10.6(8) kcal mol(-1). Line shape analysis of the absorption profiles reveals non-equilibrium dynamics that are characterized by trapping-desorption (TD) and impulsive scattering (IS) components, with each channel simply characterized by an effective "temperature" that compares very well with previous results from rotational state analysis [Perkins and Nesbitt, J. Phys. Chem. A, 2008, 112, 9324]. From a theoretical perspective, molecular dynamics (MD) simulations of CO(2) + fluorinated self-assembled monolayer surface (F-SAMs) yield translational probability distributions that are also compared with experimental results. Trajectories are parsed by θ(scat) and J, with the results rigorously corrected by flux-to-density transformation and providing comparisons in near quantitative agreement with experiment. 3D flux and velocity distributions obtained from MD simulations are also presented to illustrate the role of in- and out-of-plane scattering.

  16. High time resolution PFISR and optical observations of naturally enhanced ion acoustic lines

    Directory of Open Access Journals (Sweden)

    R. G. Michell

    2009-04-01

    Full Text Available Observations of naturally enhanced ion acoustic lines (NEIALs taken with the Poker Flat Incoherent Scatter Radar (PFISR using a mode with very high time resolution are presented. The auroral event took place over Poker Flat, Alaska on 8 February 2007 at 09:35 UT (~22:00 MLT, and the radar data are complemented by common-volume high-resolution auroral imaging. The NEIALs occurred during only one of the standard 15-s integration periods. The raw data of this time show very intermittent NEIALs which occur only during a few very short time intervals (≤1 s within the 15-s period. The time sampling of the raw data, ~19 ms on average, allows study of the time development of the NEIALs, though there are indications that even finer time resolution would be of interest. The analysis is based on the assumption that the NEIAL returns are the result of Bragg scattering from ion-acoustic waves that have been enhanced significantly above thermal levels. The spectra of the raw data indicate that although the up- and down-shifted shoulders can both become enhanced at the same time, (within 19 ms, they are most often enhanced individually. The overall power in the up-and down-shifted shoulders is approximately equal throughout the event, with the exception of one time, when very large up-shifted power was observed with no corresponding down-shifted power. This indicates that during the 480 μs pulse, the strongly enhanced ion-acoustic waves were only traveling downward and not upward. The exact time that the NEIALs occurred was when the radar beam was on the boundary of a fast-moving (~10 km/s, bright auroral structure, as seen in the high resolution auroral imaging of the magnetic zenith. When viewed with high time resolution, the occurrence of NEIALs is associated with rapid changes in auroral luminosity within the radar field of view due to fast-moving auroral fine structures.

  17. Observing lysozyme's closing and opening motions by high-resolution single-molecule enzymology.

    Science.gov (United States)

    Akhterov, Maxim V; Choi, Yongki; Olsen, Tivoli J; Sims, Patrick C; Iftikhar, Mariam; Gul, O Tolga; Corso, Brad L; Weiss, Gregory A; Collins, Philip G

    2015-06-19

    Single-molecule techniques can monitor the kinetics of transitions between enzyme open and closed conformations, but such methods usually lack the resolution to observe the underlying transition pathway or intermediate conformational dynamics. We have used a 1 MHz bandwidth carbon nanotube transistor to electronically monitor single molecules of the enzyme T4 lysozyme as it processes substrate. An experimental resolution of 2 μs allowed the direct recording of lysozyme's opening and closing transitions. Unexpectedly, both motions required 37 μs, on average. The distribution of transition durations was also independent of the enzyme's state: either catalytic or nonproductive. The observation of smooth, continuous transitions suggests a concerted mechanism for glycoside hydrolysis with lysozyme's two domains closing upon the polysaccharide substrate in its active site. We distinguish these smooth motions from a nonconcerted mechanism, observed in approximately 10% of lysozyme openings and closings, in which the enzyme pauses for an additional 40-140 μs in an intermediate, partially closed conformation. During intermediate forming events, the number of rate-limiting steps observed increases to four, consistent with four steps required in the stepwise, arrow-pushing mechanism. The formation of such intermediate conformations was again independent of the enzyme's state. Taken together, the results suggest lysozyme operates as a Brownian motor. In this model, the enzyme traces a single pathway for closing and the reverse pathway for enzyme opening, regardless of its instantaneous catalytic productivity. The observed symmetry in enzyme opening and closing thus suggests that substrate translocation occurs while the enzyme is closed.

  18. The Angular Momentum of Baryons and Dark Matter Halos Revisited

    Science.gov (United States)

    Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive-mesh refinement (AMR), we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r = 0.1R(sub vir). In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/R(sub vir) > 0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its virialised dark matter halo host. This generic result holds for halos of all masses at all redshifts, as radiative cooling ensures that a significant fraction of baryons remain trapped at the centre of the halos. Despite this injection of angular momentum enriched gas, we predict an amount for stellar discs which is in fair agreement with observations at z=0. This arises because the total specific angular momentum of the baryons (gas and stars) remains close to that of dark matter halos. Indeed, our simulations indicate that any differential loss of angular momentum amplitude between the two components is minor even though dark matter halos continuously lose between half and two-thirds of their specific angular momentum modulus as they evolve. In light of our results, a substantial revision of the standard theory of disc formation seems to be required. We propose a new scenario where gas efficiently carries the angular momentum generated

  19. Exploiting crowdsourced observations: High-resolution mapping of real-time urban air quality throughout Europe

    Science.gov (United States)

    Schneider, Philipp; Castell, Nuria; Vallejo, Islen; van den Bossche, Joris; Lahoz, William; Bartonova, Alena

    2016-04-01

    With the technology of air quality sensors improving rapidly in recent years and with an increasing number of initiatives for collecting air quality information being established worldwide, there is a rapidly increasing amount of information on air quality. Such datasets can provide unprecedented spatial detail and thus exhibit a significant potential for allowing to create observation-based high-resolution maps of air quality in the urban environment. However, most datasets of observations made within a citizen science or crowdsourcing framework tend to have highly variable characteristics in terms of quantity, accuracy, measured parameters, and representativeness, and many more. It is therefore currently unknown how to best exploit this information for mapping purposes. In order to address this challenge we present a novel approach for combining crowdsourced observations of urban air quality with model information, allowing us to produce near-real-time, high-resolution maps of air quality in the urban environment. The approach is based on data fusion techniques, which allow for combining observations with model data in a mathematically objective way and therefore provide a means of adding value to both the observations and the model. The observations are improved by filling spatio-temporal gaps in the data and the model is improved by constraining it with observations. The model further provides detailed spatial patterns in areas where no observations are available. As such, data fusion of observations from high-density low-cost sensor networks together with air quality models can contribute to significantly improving urban-scale air quality mapping. The system has been implemented to run in an automated fashion in near real-time (once every hour) for several cities in Europe. Evaluation of the methodology is being carried out using the leave-one-out cross validation technique and simulated datasets. We present case studies demonstrating the methodology for

  20. Abnormal white matter tractography of visual pathways detected by high-angular-resolution diffusion imaging (HARDI) corresponds to visual dysfunction in cortical/cerebral visual impairment

    OpenAIRE

    Bauer, Corinna M.; Heidary, Gena; Koo, Bang-Bon; Killiany, Ronald J.; Bex, Peter; Merabet, Lotfi B.

    2014-01-01

    Cortical (cerebral) visual impairment (CVI) is characterized by visual dysfunction associated with damage to the optic radiations and/or visual cortex. Typically it results from pre- or perinatal hypoxic damage to postchiasmal visual structures and pathways. The neuroanatomical basis of this condition remains poorly understood, particularly with regard to how the resulting maldevelopment of visual processing pathways relates to observations in the clinical setting. We report our investigation...

  1. High-resolution observations of flare precursors in the low solar atmosphere

    Science.gov (United States)

    Wang, Haimin; Liu, Chang; Ahn, Kwangsu; Xu, Yan; Jing, Ju; Deng, Na; Huang, Nengyi; Liu, Rui; Kusano, Kanya; Fleishman, Gregory D.; Gary, Dale E.; Cao, Wenda

    2017-03-01

    Solar flares are generally believed to be powered by free magnetic energy stored in the corona1, but the build up of coronal energy alone may be insufficient to trigger the flare to occur2. The flare onset mechanism is a critical but poorly understood problem, insights into which could be gained from small-scale energy releases known as precursors. These precursors are observed as small pre-flare brightenings in various wavelengths3-13 and also from certain small-scale magnetic configurations such as opposite-polarity fluxes14-16, where the magnetic orientation of small bipoles is opposite to that of the ambient main polarities. However, high-resolution observations of flare precursors together with the associated photospheric magnetic field dynamics are lacking. Here we study precursors of a flare using the unprecedented spatiotemporal resolution of the 1.6-m New Solar Telescope, complemented by new microwave data. Two episodes of precursor brightenings are initiated at a small-scale magnetic channel17-20 (a form of opposite-polarity flux) with multiple polarity inversions and enhanced magnetic fluxes and currents, lying near the footpoints of sheared magnetic loops. Microwave spectra corroborate that these precursor emissions originate in the atmosphere. These results provide evidence of low-atmospheric small-scale energy release, possibly linked to the onset of the main flare.

  2. High-resolution radio observations of nuclear and circumnuclear starbursts in Luminous Infrared Galaxies

    CERN Document Server

    Perez-Torres, Miguel A

    2008-01-01

    High-resolution radio observations of nearby starburst galaxies have shown that the distribution of their radio emission consists of a compact (<150 pc), high surface brightness, central radio source immersed in a low surface brightness circumnuclear halo. This radio structure is similar to that detected in bright Seyferts galaxies like NGC 7469 or Mrk 331, which display clear circumnuclear rings. While the compact, centrally located radio emission in these starbursts might be generated by a point-like source (AGN), or by the combined effect of multiple radio supernovae and supernova remnants (e.g., the evolved nuclear starburst in Arp~220), it seems well established that the circumnuclear regions of those objects host an ongoing burst of star-formation (e.g., NGC 7469; Colina et al. 2001, Alberdi et al. 2006). Therefore, high-resolution radio observations of Luminous Infra-Red Galaxies (LIRGs) in our local universe are a powerful tool to probe the dominant dust heating mechanism in their nuclear and circu...

  3. High-resolution Very Large Array observations of 18 MIPSGAL bubbles

    CERN Document Server

    Ingallinera, Adriano; Leto, Paolo; Umana, Grazia; Buemi, Carla; Bufano, Filomena; Agliozzo, Claudia; Riggi, Simone; Flagey, Nicolas; Silva, Kevin; Cerrigone, Luciano; Cavallaro, Francesco

    2016-01-01

    We present radio observations of 18 MIPSGAL bubbles performed at 5 GHz (6 cm) with the Karl G. Jansky Very Large Array in configuration B and BnA. The observations were aimed at understanding what kind of information high-resolution and high-sensitivity radio maps can supply on the circumstellar envelopes of different kinds of evolved stars and what their comparison with infrared images with similar resolution can tell us. We found that the 18 bubbles can be grouped into five categories according to their radio morphology. The three bubbles presenting a central point source in the radio images all correspond to luminous blue variable star candidates. Eleven bubbles show an elliptical shape and the total lack of a central object in the radio, and are likely associated with planetary nebulae. Under this assumption we derive their distance, their ionized mass and their distribution on the Galactic plane. We discuss the possibility that the MIPSGAL bubbles catalogue (428 objects) may contain a large fraction of a...

  4. CHIRON TOOLS: Integrated Target Submission, Scheduling and Observing Systems for a High Resolution Fiber Fed Spectrograph

    CERN Document Server

    Brewer, John M; Fischer, Debra A

    2013-01-01

    The CHIRON spectrometer is a new high-resolution, fiber-fed instrument on the 1.5 meter telescope at Cerro Tololo Inter-America Observatory (CTIO). To optimize use of the instrument and limited human resources, we have designed an integrated set of web applications allowing target submission, observing script planning, nightly script execution and logging, and access to reduced data by multiple users. The unified and easy to use interface has dramatically reduced the time needed to submit and schedule observations and improved the efficiency and accuracy of nightly operations. We present our experience to help astronomers and project managers who need to plan for the scope of effort required to commission a queue-scheduled facility instrument.

  5. High resolution transmission electron microscope observation of zero-strain deformation twinning mechanisms in Ag.

    Science.gov (United States)

    Liu, L; Wang, J; Gong, S K; Mao, S X

    2011-04-29

    We have observed a new deformation-twinning mechanism using the high resolution transmission electron microscope in polycrystalline Ag films, zero-strain twinning via nucleation, and the migration of a Σ3{112} incoherent twin boundary (ITB). This twinning mechanism produces a near zero macroscopic strain because the net Burgers vectors either equal zero or are equivalent to a Shockley partial dislocation. This observation provides new insight into the understanding of deformation twinning and confirms a previous hypothesis: detwinning could be accomplished via the nucleation and migration of Σ3{112} ITBs. The zero-strain twinning mechanism may be unique to low staking fault energy metals with implications for their deformation behavior.

  6. Spatial Scaling of Snow Observations and Microwave Emission Modeling During CLPX and Appropriate Satellite Sensor Resolution

    Science.gov (United States)

    Kim, Edward J.; Tedesco, Marco

    2005-01-01

    Accurate estimates of snow water equivalent and other properties play an important role in weather, natural hazard, and hydrological forecasting and climate modeling over a range of scales in space and time. Remote sensing-derived estimates have traditionally been of the "snapshot" type, but techniques involving models with assimilation are also being explored. In both cases, forward emission models are useful to understand the observed passive microwave signatures and developing retrieval algorithms. However, mismatches between passive microwave sensor resolutions and the scales of processes controlling subpixel heterogeneity can affect the accuracy of the estimates. Improving the spatial resolution of new passive microwave satellite sensors is a major desire in order to (literally) resolve such subpixel heterogeneity, but limited spacecraft and mission resources impose severe constraints and tradeoffs. In order to maximize science return while mitigating risk for a satellite concept, it is essential to understand the scaling behavior of snow in terms of what the sensor sees (brightness temperature) as well as in terms of the actual variability of snow. NASA's Cold Land Processes Experiment-1 (CLPX-1: Colorado, 2002 and 2003) was designed to provide data to measure these scaling behaviors for varying snow conditions in areas with forested, alpine, and meadow/pasture land cover. We will use observations from CLPX-1 ground, airborne, and satellite passive microwave sensors to examine and evaluate the scaling behavior of observed and modeled brightness temperatures and observed and retrieved snow parameters across scales from meters to 10's of kilometers. The conclusions will provide direct examples of the appropriate spatial sampling scales of new sensors for snow remote sensing. The analyses will also illustrate the effects and spatial scales of the underlying phenomena (e.g., land cover) that control subpixel heterogeneity.

  7. Professional AngularJS

    CERN Document Server

    Karpov, Valeri

    2015-01-01

    A comprehensive guide to AngularJS, Google's open-source client-side framework for app development. Most of the existing guides to AngularJS struggle to provide simple and understandable explanations for more advanced concepts. As a result, some developers who understand all the basic concepts of AngularJS struggle when it comes to building more complex real-world applications. Professional AngularJS provides a thorough understanding of AngularJS, covering everything from basic concepts, such as directives and data binding, to more advanced concepts like transclusion, build systems, and auto

  8. Measurement of the angular distribution of electrons from W-->eν decays observed in pp¯ collisions at s=1.8 TeV

    Science.gov (United States)

    Abbott, B.; Abolins, M.; Abramov, V.; Acharya, B. S.; Adams, D. L.; Adams, M.; Alves, G. A.; Amos, N.; Anderson, E. W.; Baarmand, M. M.; Babintsev, V. V.; Babukhadia, L.; Baden, A.; Baldin, B.; Balm, P. W.; Banerjee, S.; Bantly, J.; Barberis, E.; Baringer, P.; Bartlett, J. F.; Bassler, U.; Bean, A.; Begel, M.; Belyaev, A.; Beri, S. B.; Bernardi, G.; Bertram, I.; Besson, A.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Bhattacharjee, M.; Blazey, G.; Blessing, S.; Boehnlein, A.; Bojko, N. I.; Borcherding, F.; Brandt, A.; Breedon, R.; Briskin, G.; Brock, R.; Brooijmans, G.; Bross, A.; Buchholz, D.; Buehler, M.; Buescher, V.; Burtovoi, V. S.; Butler, J. M.; Canelli, F.; Carvalho, W.; Casey, D.; Casilum, Z.; Castilla-Valdez, H.; Chakraborty, D.; Chan, K. M.; Chekulaev, S. V.; Cho, D. K.; Choi, S.; Chopra, S.; Christenson, J. H.; Chung, M.; Claes, D.; Clark, A. R.; Cochran, J.; Coney, L.; Connolly, B.; Cooper, W. E.; Coppage, D.; Cummings, M. A.; Cutts, D.; Dahl, O. I.; Davis, G. A.; Davis, K.; de, K.; del Signore, K.; Demarteau, M.; Demina, R.; Demine, P.; Denisov, D.; Denisov, S. P.; Desai, S.; Diehl, H. T.; Diesburg, M.; di Loreto, G.; Doulas, S.; Draper, P.; Ducros, Y.; Dudko, L. V.; Duensing, S.; Dugad, S. R.; Dyshkant, A.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Engelmann, R.; Eno, S.; Eppley, G.; Ermolov, P.; Eroshin, O. V.; Estrada, J.; Evans, H.; Evdokimov, V. N.; Fahland, T.; Feher, S.; Fein, D.; Ferbel, T.; Fisk, H. E.; Fisyak, Y.; Flattum, E.; Fleuret, F.; Fortner, M.; Frame, K. C.; Fuess, S.; Gallas, E.; Galyaev, A. N.; Gartung, P.; Gavrilov, V.; Genik, R. J.; Genser, K.; Gerber, C. E.; Gershtein, Y.; Gibbard, B.; Gilmartin, R.; Ginther, G.; Gómez, B.; Gómez, G.; Goncharov, P. I.; González Solís, J. L.; Gordon, H.; Goss, L. T.; Gounder, K.; Goussiou, A.; Graf, N.; Graham, G.; Grannis, P. D.; Green, J. A.; Greenlee, H.; Grinstein, S.; Groer, L.; Grudberg, P.; Grünendahl, S.; Gupta, A.; Gurzhiev, S. N.; Gutierrez, G.; Gutierrez, P.; Hadley, N. J.; Haggerty, H.; Hagopian, S.; Hagopian, V.; Hahn, K. S.; Hall, R. E.; Hanlet, P.; Hansen, S.; Hauptman, J. M.; Hays, C.; Hebert, C.; Hedin, D.; Heinson, A. P.; Heintz, U.; Heuring, T.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Hoftun, J. S.; Hou, S.; Huang, Y.; Ito, A. S.; Jerger, S. A.; Jesik, R.; Johns, K.; Johnson, M.; Jonckheere, A.; Jones, M.; Jöstlein, H.; Juste, A.; Kahn, S.; Kajfasz, E.; Karmanov, D.; Karmgard, D.; Kehoe, R.; Kim, S. K.; Klima, B.; Klopfenstein, C.; Knuteson, B.; Ko, W.; Kohli, J. M.; Kostritskiy, A. V.; Kotcher, J.; Kotwal, A. V.; Kozelov, A. V.; Kozlovsky, E. A.; Krane, J.; Krishnaswamy, M. R.; Krzywdzinski, S.; Kubantsev, M.; Kuleshov, S.; Kulik, Y.; Kunori, S.; Kuznetsov, V. E.; Landsberg, G.; Leflat, A.; Lehner, F.; Li, J.; Li, Q. Z.; Lima, J. G.; Lincoln, D.; Linn, S. L.; Linnemann, J.; Lipton, R.; Lucotte, A.; Lueking, L.; Lundstedt, C.; Maciel, A. K.; Madaras, R. J.; Manankov, V.; Mao, H. S.; Marshall, T.; Martin, M. I.; Martin, R. D.; Mauritz, K. M.; May, B.; Mayorov, A. A.; McCarthy, R.; McDonald, J.; McMahon, T.; Melanson, H. L.; Meng, X. C.; Merkin, M.; Merritt, K. W.; Miao, C.; Miettinen, H.; Mihalcea, D.; Mincer, A.; Mishra, C. S.; Mokhov, N.; Mondal, N. K.; Montgomery, H. E.; Moore, R. W.; Mostafa, M.; da Motta, H.; Nagy, E.; Nang, F.; Narain, M.; Narasimham, V. S.; Neal, H. A.; Negret, J. P.; Negroni, S.; Norman, D.; Oesch, L.; Oguri, V.; Olivier, B.; Oshima, N.; Padley, P.; Pan, L. J.; Para, A.; Parashar, N.; Partridge, R.; Parua, N.; Paterno, M.; Patwa, A.; Pawlik, B.; Perkins, J.; Peters, M.; Peters, O.; Piegaia, R.; Piekarz, H.; Pope, B. G.; Popkov, E.; Prosper, H. B.; Protopopescu, S.; Qian, J.; Quintas, P. Z.; Raja, R.; Rajagopalan, S.; Ramberg, E.; Rapidis, P. A.; Reay, N. W.; Reucroft, S.; Rha, J.; Rijssenbeek, M.; Rockwell, T.; Roco, M.; Rubinov, P.; Ruchti, R.; Rutherfoord, J.; Santoro, A.; Sawyer, L.; Schamberger, R. D.; Schellman, H.; Schwartzman, A.; Sculli, J.; Sen, N.; Shabalina, E.; Shankar, H. C.; Shivpuri, R. K.; Shpakov, D.; Shupe, M.; Sidwell, R. A.; Simak, V.; Singh, H.; Singh, J. B.; Sirotenko, V.; Slattery, P.; Smith, E.; Smith, R. P.; Snihur, R.; Snow, G. R.; Snow, J.; Snyder, S.; Solomon, J.; Sorín, V.; Sosebee, M.; Sotnikova, N.; Soustruznik, K.; Souza, M.; Stanton, N. R.; Steinbrück, G.; Stephens, R. W.; Stevenson, M. L.; Stichelbaut, F.; Stoker, D.; Stolin, V.; Stoyanova, D. A.; Strauss, M.; Streets, K.; Strovink, M.; Stutte, L.; Sznajder, A.; Taylor, W.; Tentindo-Repond, S.; Thompson, J.; Toback, D.; Tripathi, S. M.; Trippe, T. G.; Turcot, A. S.; Tuts, P. M.; van Gemmeren, P.; Vaniev, V.; van Kooten, R.; Varelas, N.; Volkov, A. A.; Vorobiev, A. P.; Wahl, H. D.; Wang, H.; Wang, Z.-M.; Warchol, J.; Watts, G.; Wayne, M.; Weerts, H.; White, A.; White, J. T.; Whiteson, D.; Wightman, J. A.; Wijngaarden, D. A.; Willis, S.; Wimpenny, S. J.; Wirjawan, J. V.; Womersley, J.; Wood, D. R.; Yamada, R.; Yamin, P.; Yasuda, T.; Yip, K.; Youssef, S.; Yu, J.; Yu, Z.; Zanabria, M.; Zheng, H.; Zhou, Z.; Zhu, Z. H.; Zielinski, M.; Zieminska, D.; Zieminski, A.; Zutshi, V.; Zverev, E. G.; Zylberstejn, A.

    2001-04-01

    We present the first measurement of the electron angular distribution parameter α2 in W-->eν events produced in proton-antiproton collisions as a function of the W boson transverse momentum. Our analysis is based on data collected using the DØ detector during the 1994-1995 Fermilab Tevatron run. We compare our results with next-to-leading order perturbative QCD, which predicts an angular distribution of (1+/-α1 cos θ*+α2 cos2 θ*), where θ* is the polar angle of the electron in the Collins-Soper frame. In the presence of QCD corrections, the parameters α1 and α2 become functions of pWT, the W boson transverse momentum. This measurement provides a test of next-to-leading order QCD corrections which are a non-negligible contribution to the W boson mass measurement.

  9. NASA LaRC airborne high spectral resolution lidar aerosol measurements during MILAGRO: observations and validation

    Directory of Open Access Journals (Sweden)

    L. I. Kleinman

    2009-07-01

    Full Text Available The NASA Langley Research Center (LaRC airborne High Spectral Resolution Lidar (HSRL measures vertical profiles of aerosol extinction, backscatter, and depolarization at both 532 nm and 1064 nm. In March of 2006 the HSRL participated in the Megacity Initiative: Local and Global Research Observations (MILAGRO campaign along with several other suites of instruments deployed on both aircraft and ground based platforms. This paper presents high spatial and vertical resolution HSRL measurements of aerosol extinction and optical depth from MILAGRO and comparisons of those measurements with similar measurements from other sensors and model predictions. HSRL measurements coincident with airborne in situ aerosol scattering and absorption measurements from two different instrument suites on the C-130 and G-1 aircraft, airborne aerosol optical depth (AOD and extinction measurements from an airborne tracking sunphotometer on the J-31 aircraft, and AOD from a network of ground based Aerosol Robotic Network (AERONET sun photometers are presented as a validation of the HSRL aerosol extinction and optical depth products. Regarding the extinction validation, we find bias differences between HSRL and these instruments to be less than 3% (0.01 km−1 at 532 nm, the wavelength at which the HSRL technique is employed. The rms differences at 532 nm were less than 50% (0.015 km−1. To our knowledge this is the most comprehensive validation of the HSRL measurement of aerosol extinction and optical depth to date. The observed bias differences in ambient aerosol extinction between HSRL and other measurements is within 15–20% at visible wavelengths, found by previous studies to be the differences observed with current state-of-the-art instrumentation (Schmid et al., 2006.

  10. NASA LaRC airborne high spectral resolution lidar aerosol measurements during MILAGRO: observations and validation

    Directory of Open Access Journals (Sweden)

    R. R. Rogers

    2009-04-01

    Full Text Available The NASA Langley Research Center (LaRC airborne High Spectral Resolution Lidar (HSRL measures vertical profiles of aerosol extinction, backscatter, and depolarization at both 532 nm and 1064 nm. In March of 2006 the HSRL participated in the Megacity Initiative: Local and Global Research Observations (MILAGRO campaign along with several other suites of instruments deployed on both aircraft and ground based platforms. This paper presents high spatial and vertical resolution HSRL measurements of aerosol extinction and optical depth from MILAGRO and comparisons of those measurements with similar measurements from other sensors and model predictions. HSRL measurements coincident with airborne in situ aerosol scattering and absorption measurements from two different instrument suites on the C-130 and G-1 aircraft, airborne aerosol optical depth (AOD and extinction measurements from an airborne tracking sunphotometer on the J-31 aircraft, and AOD from a network of ground based Aerosol Robotic Network (AERONET sun photometers are presented as a validation of the HSRL aerosol extinction and optical depth products. Regarding the extinction validation, we find bias differences between HSRL and these instruments to be less than 3% (0.01 km−1 at 532 nm, the wavelength at which the HSRL technique is employed. The rms differences at 532 nm were less than 50% (0.015 km−1. To our knowledge this is the most comprehensive validation of the HSRL measurement of aerosol extinction and optical depth to date. The observed bias differences in ambient aerosol extinction between HSRL and other measurements is within 15–20% at visible wavelengths, found by previous studies to be the differences observed with current state-of-the-art instrumentation (Schmid et al., 2006.

  11. High-resolution sensing for precision agriculture: from Earth-observing satellites to unmanned aerial vehicles

    Science.gov (United States)

    McCabe, Matthew F.; Houborg, Rasmus; Lucieer, Arko

    2016-10-01

    With global population projected to approach 9 billion by 2050, it has been estimated that a 40% increase in cereal production will be required to satisfy the worlds growing nutritional demands. Any such increases in agricultural productivity are likely to occur within a system that has limited room for growth and in a world with a climate that is different from that of today. Fundamental to achieving food and water security, is the capacity to monitor the health and condition of agricultural systems. While space-agency based satellites have provided the backbone for earth observation over the last few decades, many developments in the field of high-resolution earth observation have been advanced by the commercial sector. These advances relate not just to technological developments in the use of unmanned aerial vehicles (UAVs), but also the advent of nano-satellite constellations that offer a radical shift in the way earth observations are now being retrieved. Such technologies present opportunities for improving our description of the water, energy and carbon cycles. Efforts towards developing new observational techniques and interpretative frameworks are required to provide the tools and information needed to improve the management and security of agricultural and related sectors. These developments are one of the surest ways to better manage, protect and preserve national food and water resources. Here we review the capabilities of recently deployed satellite systems and UAVs and examine their potential for application in precision agriculture.

  12. High Resolution Spectroscopic Database for the NASA Earth Observing System Program

    Science.gov (United States)

    Rothman, Laurence

    2004-01-01

    The purpose of this project has been to develop and enhance the HITRAN molecular spectroscopic database and associated software to support the observational programs of the Earth Observing System (EOS). Emphasis has been on the EOS projects: the Atmospheric Infrared Sounder (AIRS), the High-Resolution Dynamics Limb Sounder (HIRDLS), Measurements of Pollution in the Troposphere (MOPITT), the Tropospheric Emission Spectrometer (TES), and the Stratospheric Aerosol and Gas Experiment (SAGE III). The HITRAN program is also involved in the Ozone Monitoring Experiment (OMI). The data requirements of these programs in terms of spectroscopy are varied with respect to constituents being observed, required remote-sensing parameters, and spectral coverage. A general requisite is for additional spectral parameters and improvements to existing molecular bands sufficient for the simulation of the observations leading to retrieval of the atmospheric state. In addition, cross-section data for heavier molecular species must be expanded and made amenable to modeling in remote sensing. The effort in the project also includes developing software and distribution to make access, manipulation, and use of HITRAN functional to the EOS program.

  13. High-Resolution Spectroscopic Database for the NASA Earth Observing System Program

    Science.gov (United States)

    Rothman, Laurence S.

    2004-01-01

    The purpose of this project is to develop and enhance the HITRAN molecular spectroscopic database and associated - software to support the observational programs of the Earth observing System (EOS). In particular, the focus is on the EOS projects: the Atmospheric Infrared Sounder (AIRS), the High-Resolution Dynamics Limb Sounder (HIRDLS), Measurements of Pollution in the Troposphere (MOPITT), the Tropospheric Emission Spectrometer (TES), and the Stratospheric Aerosol and Gas Experiment (SAGE III). The HITRAN program is also involved in the Ozone Monitoring Experiment (OMI). The data requirements of these programs in terms of spectroscopy are varied with respect to constituents being observed, required remote-sensing parameters, and spectral coverage. A general requisite is for additional spectral parameters and improvements to existing molecular bands sufficient for the simulation of the observations leading to retrieval of the atmospheric state. In addition cross-section data for heavier molecular species must be expanded and made amenable to modeling in remote sensing. The effort in the project also includes developing software and distribution to make access, manipulation, and use HITRAN functional to the EOS program.

  14. High-resolution sensing for precision agriculture: from Earth-observing satellites to unmanned aerial vehicles

    KAUST Repository

    McCabe, Matthew

    2016-10-25

    With global population projected to approach 9 billion by 2050, it has been estimated that a 40% increase in cereal production will be required to satisfy the worlds growing nutritional demands. Any such increases in agricultural productivity are likely to occur within a system that has limited room for growth and in a world with a climate that is different from that of today. Fundamental to achieving food and water security, is the capacity to monitor the health and condition of agricultural systems. While space-Agency based satellites have provided the backbone for earth observation over the last few decades, many developments in the field of high-resolution earth observation have been advanced by the commercial sector. These advances relate not just to technological developments in the use of unmanned aerial vehicles (UAVs), but also the advent of nano-satellite constellations that offer a radical shift in the way earth observations are now being retrieved. Such technologies present opportunities for improving our description of the water, energy and carbon cycles. Efforts towards developing new observational techniques and interpretative frameworks are required to provide the tools and information needed to improve the management and security of agricultural and related sectors. These developments are one of the surest ways to better manage, protect and preserve national food and water resources. Here we review the capabilities of recently deployed satellite systems and UAVs and examine their potential for application in precision agriculture.

  15. A demonstration of the conservation of the orbital angular momentum of Earth

    Science.gov (United States)

    Pellizza, Leonardo J.; Mayochi, Mariano G.; Ciocci Brazzano, Ligia; Pedrosa, Susana E.

    2015-12-01

    We describe a simple but quantitative experiment to demonstrate the conservation of angular momentum. We measure the correlation of the apparent radius and angular velocity of the Sun with respect to the stars, due to the conservation of the angular momentum of Earth in its orbit. We also determine the direction of Earth's angular momentum vector and show that it is conserved. The experiment can be performed using a small telescope and a digital camera. It is conceptually simple, allowing students to get direct physical insight from the data. The observations are performed near the resolution limit imposed by the atmosphere, and in the presence of strong competing effects. These effects necessitate a careful experimental setup and allow students to improve their skills in experimentation.

  16. High spatial resolution observations of NGC 7027 with a 10 micron array camera

    Science.gov (United States)

    Arens, J. F.; Lamb, G. M.; Peck, M. C.; Moseley, H.; Hoffmann, W. F.; Tresch-Fienberg, R.; Fazio, G. G.

    1984-01-01

    First observations of a planetary nebula with an infrared charge injection device (CID) array camera are reported. The 10 micron images of NGC 7027 have spatial resolution comparable to that of the highest resolution (less than 2 arcsec) radio aperture-synthesis maps of this source. A much closer correspondence between the mid-infrared and radio appearance of NGC 7027 was found than was known previously, confirming that warm dust is coextensive and well mixed with the gas in the ionized zone. Using maps at three wavelengths, the spatial dependence of the shape of the 8-13 micron spectrum within the nebula is examined. The dip at 9.60 microns is shallowest in regions of enhanced optical extinction (as determined from new images near 4000 and 9000 A obtained with an optical charge coupled device). The 9.60 micron emission is strongest in these same positions. It is shown that the results may be explained not by silicate absorption, but by a combination of emission from two distinct grain populations, one of which is also partly responsible for the variation in extinction across the nebula.

  17. High resolution telescope and spectrograph observations of solar fine structure in the 1600 A region

    Science.gov (United States)

    Cook, J. W.; Brueckner, G. E.; Bartoe, J.-D. F.

    1983-01-01

    High spatial resolution spectroheliograms of the 1600 A region obtained during the HRTS rocket flight of 1978 February 13 are presented. The morphology, fine structure, and temporal behavior of emission bright points (BPs) in active and quiet regions are illustrated. In quiet regions, network elements persist as morphological units, although individual BPs may vary in intensity while usually lasting the flight duration. In cell centers, the BPs are highly variable on a 1 minute time scale. BPs in plages remain more constant in brightness over the observing sequence. BPs cover less than 4 percent of the quiet surface. The lifetime and degree of packing of BPs vary with the local strength of the magnetic field.

  18. Dynamics of Saturn’s 2010 Great White Spot from high-resolution Cassini ISS observations

    Science.gov (United States)

    Hueso, Ricardo; Sánchez-Lavega, A.; del Río-Gaztelurrutia, T.

    2012-10-01

    On December 5th 2010 a storm erupted in Saturn’s North Temperate latitudes which were experiencing early spring season. The storm quickly developed to a planet-wide disturbance of the Great White Spot type. The ISS instrument onboard Cassini acquired its first images of the storm on 23th December 2010 and performed repeated observations with a variety of spatial resolutions over the nearly 10 months period the storm continued active. Here we present an analysis of two of the image sequences with better spatial resolution of the mature storm when it was fully developed and very active. We used an image correlation algorithm to measure the cloud motions obtained from images separated 20 minutes and obtained 16,000 wind tracers in a domain of 60 degrees longitude per 20 degrees in latitude. Intense zonal and meridional motions accompanied the storm and reached values of 120 m/s in particular regions of the active storm. The storm released a chain of anticyclonic and cyclonic vortices at planetocentric latitudes of 36° and 32° respectively. The short time difference between the images results in estimated wind uncertainties of 15 m/s that did not allow to perform a complete analysis of the turbulence and kinetic spectrum of the motions. We identify locations of the updrafts and link those with the morphology in different observing filters. The global behaviour of the storm was examined in images separated by 10 hours confirming the intensity of the winds and the global behaviour of the vortices. Acknowledgments: This work was supported by the Spanish MICIIN project AYA2009-10701 with FEDER funds, by Grupos Gobierno Vasco IT-464-07 and by Universidad País Vasco UPV/EHU through program UFI11/55.

  19. Transverse and longitudinal angular momenta of light

    CERN Document Server

    Bliokh, Konstantin Y

    2015-01-01

    We review basic physics and novel types of optical angular momentum. We start with a theoretical overview of momentum and angular momentum properties of generic optical fields, and discuss methods for their experimental measurements. In particular, we describe the well-known longitudinal (i.e., aligned with the mean momentum) spin and orbital angular momenta in polarized vortex beams. Then, we focus on the transverse (i.e., orthogonal to the mean momentum) spin and orbital angular momenta, which were recently actively discussed in theory and observed in experiments. First, the recently-discovered transverse spin angular momenta appear in various structured fields: evanescent waves, interference fields, and focused beams. We show that there are several kinds of transverse spin angular momentum, which differ strongly in their origins and physical properties. We describe extraordinary features of the transverse optical spins and overview recent experiments. In particular, the helicity-independent transverse spin...

  20. Slipping reconnection in a solar flare observed in high resolution with the GREGOR solar telescope

    CERN Document Server

    Sobotka, M; Denker, C; Balthasar, H; Jurčák, J; Liu, W; Berkefeld, T; Vera, M Collados; Feller, A; Hofmann, A; Kneer, F; Kuckein, C; Lagg, A; Louis, R E; von der Lühe, O; Nicklas, H; Schlichenmaier, R; Schmidt, D; Schmidt, W; Sigwarth, M; Solanki, S K; Soltau, D; Staude, J; Strassmeier, K G; Volkmer, R; Waldmann, T

    2016-01-01

    A small flare ribbon above a sunspot umbra in active region 12205 was observed on November 7, 2014, at 12:00 UT in the blue imaging channel of the 1.5 m GREGOR telescope, using a 1 A Ca II H interference filter. Context observations from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO), the Solar Optical Telescope (SOT) onboard Hinode, and the Interface Region Imaging Spectrograph (IRIS) show that this ribbon is part of a larger one that extends through the neighboring positive polarities and also participates in several other flares within the active region. We reconstructed a time series of 140 seconds of Ca II H images by means of the multiframe blind deconvolution method, which resulted in spatial and temporal resolutions of 0.1 arcsec and 1 s. Light curves and horizontal velocities of small-scale bright knots in the observed flare ribbon were measured. Some knots are stationary, but three move along the ribbon with speeds of 7-11 km/s. Two of them move in the opposite d...

  1. Observations of radio-quiet quasars at 10mas resolution by use of gravitational lensing

    CERN Document Server

    Jackson, Neal; Roberts, Carl; Sluse, Dominique; Stacey, Hannah; Vives-Arias, Hector; Wucknitz, Olaf; Volino, Filomena

    2015-01-01

    We present VLA detections of radio emission in four four-image gravitational lens systems with quasar sources: HS0810+2554, RXJ0911+0511, HE0435$-$1223 and SDSSJ0924+0219, and e-MERLIN observations of two of the systems. The first three are detected at a high level of significance, and SDSS J0924+0219 is detected. HS0810+2554 is resolved, allowing us for the first time to achieve 10-mas resolution of the source frame in the structure of a radio quiet quasar. The others are unresolved or marginally resolved. All four objects are among the faintest radio sources yet detected, with intrinsic flux densities in the range 1-5$\\mu$Jy; such radio objects, if unlensed, will only be observable routinely with the Square Kilometre Array. The observations of HS0810+2554, which is also detected with e-MERLIN, strongly suggest the presence of a mini-AGN, with a radio core and milliarcsecond scale jet. The flux densities of the lensed images in all but HE0435-1223 are consistent with smooth galaxy lens models without the req...

  2. PolarBase: a data base of high resolution spectropolarimetric stellar observations

    CERN Document Server

    Petit, P; Théado, S; Paletou, F; Manset, N; Morin, J; Marsden, S C; Jeffers, S V

    2014-01-01

    PolarBase is an evolving data base that contains all stellar data collected with the ESPaDOnS and NARVAL high-resolution spectropolarimeters, in their reduced form, as soon as they become public. As of early 2014, observations of 2,000 stellar objects throughout the Hertzsprung-Russell diagram are available. Intensity spectra are available for all targets, and the majority of the observations also include simultaneous spectra in circular or linear polarization, with the majority of the polarimetric measurements being performed only in circularly polarized light (Stokes V). Observations are associated with a cross-correlation pseudo-line profile in all available Stokes parameters, greatly increasing the detectability of weak polarized signatures. Stokes V signatures are detected for more than 300 stars of all masses and evolutionary stages, and linear polarization is detected in 35 targets. The detection rate in Stokes V is found to be anti-correlated with the stellar effective temperature. This unique set of ...

  3. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations.

    Science.gov (United States)

    Gao, Wang; Gao, Chengfa; Pan, Shuguo; Wang, Denghui; Deng, Jiadong

    2015-10-30

    The regional constellation of the BeiDou navigation satellite system (BDS) has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK) positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR). We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL) ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2) ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF) strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system.

  4. On Angular Momentum

    Science.gov (United States)

    Schwinger, J.

    1952-01-26

    The commutation relations of an arbitrary angular momentum vector can be reduced to those of the harmonic oscillator. This provides a powerful method for constructing and developing the properties of angular momentum eigenvectors. In this paper many known theorems are derived in this way, and some new results obtained. Among the topics treated are the properties of the rotation matrices; the addition of two, three, and four angular momenta; and the theory of tensor operators.

  5. MATISSE a web-based tool to access, visualize and analyze high resolution minor bodies observation

    Science.gov (United States)

    Zinzi, Angelo; Capria, Maria Teresa; Palomba, Ernesto; Antonelli, Lucio Angelo; Giommi, Paolo

    2016-07-01

    In the recent years planetary exploration missions acquired data from minor bodies (i.e., dwarf planets, asteroid and comets) at a detail level never reached before. Since these objects often present very irregular shapes (as in the case of the comet 67P Churyumov-Gerasimenko target of the ESA Rosetta mission) "classical" bidimensional projections of observations are difficult to understand. With the aim of providing the scientific community a tool to access, visualize and analyze data in a new way, ASI Science Data Center started to develop MATISSE (Multi-purposed Advanced Tool for the Instruments for the Solar System Exploration - http://tools.asdc.asi.it/matisse.jsp) in late 2012. This tool allows 3D web-based visualization of data acquired by planetary exploration missions: the output could either be the straightforward projection of the selected observation over the shape model of the target body or the visualization of a high-order product (average/mosaic, difference, ratio, RGB) computed directly online with MATISSE. Standard outputs of the tool also comprise downloadable files to be used with GIS software (GeoTIFF and ENVI format) and 3D very high-resolution files to be viewed by means of the free software Paraview. During this period the first and most frequent exploitation of the tool has been related to visualization of data acquired by VIRTIS-M instruments onboard Rosetta observing the comet 67P. The success of this task, well represented by the good number of published works that used images made with MATISSE confirmed the need of a different approach to correctly visualize data coming from irregular shaped bodies. In the next future the datasets available to MATISSE are planned to be extended, starting from the addition of VIR-Dawn observations of both Vesta and Ceres and also using standard protocols to access data stored in external repositories, such as NASA ODE and Planetary VO.

  6. Dynamics of the MAP IOP 15 severe Mistral event: Observations and high-resolution numerical simulations

    Science.gov (United States)

    Guénard, V.; Drobinski, P.; Caccia, J. L.; Tedeschi, G.; Currier, P.

    2006-04-01

    This paper investigates the fundamental processes involved in a severe Mistral event that occurred during the Mesoscale Alpine Program (from 6 to 9 November 1999). The Mistral refers to a violent north/north-westerly wind blowing in south-eastern France from the Rhône valley to the French Riviera. The study is based on measurements from radiosoundings launched from Lyon and Nîmes and from two UHF wind profilers located near Marseille and Toulon allowing a good description of the flow in the complex terrain formed by the south-western Alps. Observational results are compared with RAMS non-hydrostatic numerical simulations performed with 27 km, 9 km and 3 km nested grids. The numerical simulations capture the flow complexity both upstream of the Alps and in the coastal area affected by the Mistral. They correctly reproduce horizontal wind speeds and directions, vertical velocities, virtual potential temperature and relative humidity documented by the observational network. The simulations are used to point out the main dynamical processes generating the Mistral. It is found that flow splitting around the Alps and around the isolated peaks bordering the south-eastern part of the Rhône valley (Mont Ventoux 1909 m, Massif du Lubéron 1425 m) induces the low-level jet observed near Marseille that lasts for 36 hours. The high-resolution simulation indicates that the transient low-level jet lasting for only 9 hours observed at Toulon is due to a gravity wave breaking over local topography (the Sainte Baume 1147 m) where hydraulic jumps are involved. A mountain wake with two opposite-sign potential-vorticity banners is generated. The mesoscale wake explains the westward progression of the large-scale Alpine wake.

  7. Technical Note: The effect of sensor resolution on the number of cloud-free observations from space

    Directory of Open Access Journals (Sweden)

    J. M. Krijger

    2007-06-01

    Full Text Available Air quality and surface emission inversions are likely to be focal points for future satellite missions on atmospheric composition. Most important for these applications is sensitivity to the atmospheric composition in the lowest few kilometers of the troposphere. Reduced sensitivity by clouds needs to be minimized. In this study we have quantified the increase in number of useful footprints, i.e. footprints which are sufficient cloud-free, as a function of sensor resolution (footprint area. High resolution (1 km×1 km MODIS TERRA cloud mask observations are aggregated to lower resolutions. Statistics for different thresholds on cloudiness are applied. For each month in 2004 four days of MODIS data are analyzed. Globally the fraction of cloud-free observations drops from 16% at 100 km2 resolution to only 3% at 10 000 km2 if not a single MODIS observation within a footprint is allowed to be cloudy. If up to 5% or 20% of a footprint is allowed to be cloudy, the fraction of cloud-free observations is 9% or 17%, respectively, at 10 000 km2 resolution. The probability of finding cloud-free observations for different sensor resolutions is also quantified as a function of geolocation and season, showing examples over Europe and northern South America (ITCZ.

  8. High temporal resolution Br2, BrCl and BrO observations in coastal Antarctica

    Directory of Open Access Journals (Sweden)

    R. von Glasow

    2013-02-01

    Full Text Available There are few observations of speciated inorganic bromine in polar regions against which to test current theory. Here we report the first high temporal resolution measurements of Br2, BrCl and BrO in coastal Antarctica, made at Halley during spring 2007 using a Chemical Ionisation Mass Spectrometer (CIMS. We find indications for an artefact in daytime BrCl measurements arising from conversion of HOBr, similar to that already identified for observations of Br2 made using a similar CIMS method. Using the MISTRA model, we estimate that the artefact represents a conversion of HOBr to Br2 of the order of several tens of percent, while that for HOBr to BrCl is less but non-negligible. If the artefact is indeed due to HOBr conversion, then nighttime observations were unaffected. It also appears that all daytime BrO observations were artefact-free. Mixing ratios of BrO, Br2 and BrCl ranged from instrumental detection limits to 13 pptv (daytime, 45 pptv (nighttime, and 6 pptv (nighttime, respectively. We see considerable variability in the Br2 and BrCl observations over the measurement period which is strongly linked to the prevailing meteorology, and thus air mass origin. Higher mixing ratios of these species were generally observed when air had passed over the sea-ice zone prior to arrival at Halley, than from over the continent. Variation in the diurnal structure of BrO is linked to previous model work where differences in the photolysis spectra of Br2 and O3 is suggested to lead to a BrO maximum at sunrise and sunset, rather than a noon-time maxima. This suite of Antarctic data provides the first analogue to similar measurements made in the Arctic, and of note is that our maximum measured BrCl (nighttime is less than half of the maximum measured during a similar period (spring-time in the Arctic (also nighttime. This difference in maximum measured BrCl may also be the cause of a difference in the Br2 : BrCl ratio between the Arctic and Antarctic. An

  9. Solar Flare Chromospheric Line Emission: Comparison Between IBIS High-resolution Observations and Radiative Hydrodynamic Simulations

    CERN Document Server

    da Costa, Fatima Rubio; Petrosian, Vahé; Dalda, Alberto Sainz; Liu, Wei

    2014-01-01

    Solar flares involve impulsive energy release, which results in enhanced radiation in a broad spectral and at a wide height range. In particular, line emission from the chromosphere (lower atmosphere) can provide critical diagnostics of plasma heating processes. Thus, a direct comparison between high-resolution spectroscopic observations and advanced numerical modeling results can be extremely valuable, but has not been attempted so far. We present in this paper such a self-consistent investigation of an M3.0 flare observed by the Dunn Solar Telescope's (DST) Interferometric Bi-dimensional Spectrometer (IBIS) on 2011 September 24 that we have modeled with the radiative hydrodynamic code RADYN (Carlsson & Stein 1992, 1997; Abbett & Hawley 1999; Allred et al. 2005). We obtained images and spectra of the flaring region with IBIS in H$\\alpha$ 6563 \\AA\\ and Ca II 8542 \\AA, and with the Reuven Ramaty High Energy Solar Spectroscope Imager (RHESSI) in X-rays. The latter was used to infer the non-thermal elect...

  10. High-resolution observations of gamma-ray line emission from SN 1987A

    Science.gov (United States)

    Sandie, W. G.; Nakano, G. H.; Chase, L. F., Jr.; Fishman, G. J.; Meegan, C. A.; Wilson, R. B.; Paciesas, W. S.; Lasche, G. P.

    1988-11-01

    A balloon-borne gamma-ray spectrometer was flown from Alice springs, Australia, 1987 October 29 - 31, nominally 250 days after the supernova event. High-resolution data, typically 2.5 keV at 1.33 MeV, were obtained for two transits of the supernova. A significant net flux of gamma rays with energy 847 keV was observed from the direction of SN 1987A on each transit. No prominent gamma-ray features were seen at other energies. A preliminary estimate of the line flux is (5.1±1.7)×10-4photons cm-2s-1. The net flux observed in the first supernova transit extends from 838 keV to 850 keV and may be evidence of dynamical broadening of the 847 keV line. The total excess flux from 838 keV to 850 keV corresponds to (1.0±0.28)×10-3photons cm-2s-1. This line may be interpreted as emission from the first excited state of 56Fe due to the radioactive decay of 56Co.

  11. LAMOST OBSERVATIONS IN THE KEPLER FIELD. I. DATABASE OF LOW-RESOLUTION SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Cat, P. De; Ren, A. B.; Yang, X. H. [Royal observatory of Belgium, Ringlaan 3, B-1180 Brussel (Belgium); Fu, J. N. [Department of Astronomy, Beijing Normal University, 19 Avenue Xinjiekouwai, Beijing 100875 (China); Shi, J. R.; Luo, A. L.; Yang, M.; Wang, J. L.; Zhang, H. T.; Shi, H. M.; Zhang, W. [Key Lab for Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Dong, Subo [Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Road 5, Hai Dian District, Beijing, 100871 (China); Catanzaro, G.; Frasca, A. [INAF—Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Corbally, C. J. [Vatican Observatory Research Group, Steward Observatory, Tucson, AZ 85721-0065 (United States); Gray, R. O. [Department of Physics and Astronomy, Appalachian State University, Boone, NC 28608 (United States); Żakowicz, J. Molenda- [Astronomical Institute of the University of Wrocław, ul. Kopernika 11, 51-622 Wrocław (Poland); Uytterhoeven, K. [Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Briquet, M. [Institut d’Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août 19C, B-4000 Liège (Belgium); Bruntt, H., E-mail: Peter.DeCat@oma.be [Stellar Astrophysics Center, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); and others

    2015-09-15

    The nearly continuous light curves with micromagnitude precision provided by the space mission Kepler are revolutionizing our view of pulsating stars. They have revealed a vast sea of low-amplitude pulsation modes that were undetectable from Earth. The long time base of Kepler light curves allows for the accurate determination of the frequencies and amplitudes of pulsation modes needed for in-depth asteroseismic modeling. However, for an asteroseismic study to be successful, the first estimates of stellar parameters need to be known and they cannot be derived from the Kepler photometry itself. The Kepler Input Catalog provides values for the effective temperature, surface gravity, and metallicity, but not always with sufficient accuracy. Moreover, information on the chemical composition and rotation rate is lacking. We are collecting low-resolution spectra for objects in the Kepler field of view with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (lamost, Xinglong observatory, China). All of the requested fields have now been observed at least once. In this paper, we describe those observations and provide a useful database for the whole astronomical community.

  12. SOFIA/EXES Observations of Water Absorption in the Protostar AFGL 2591 at High Spectral Resolution

    CERN Document Server

    Indriolo, Nick; DeWitt, C N; Richter, M J; Boogert, A C A; Harper, G M; Jaffe, D T; Kulas, K R; McKelvey, M E; Ryde, N; Vacca, W

    2015-01-01

    We present high spectral resolution (~3 km/s) observations of the nu_2 ro-vibrational band of H2O in the 6.086--6.135 micron range toward the massive protostar AFGL 2591 using the Echelon-Cross-Echelle Spectrograph (EXES) on the Stratospheric Observatory for Infrared Astronomy (SOFIA). Ten absorption features are detected in total, with seven caused by transitions in the nu_2 band of H2O, two by transitions in the first vibrationally excited nu_2 band of H2O, and one by a transition in the nu_2 band of H2{18}O. Among the detected transitions is the nu_2 1(1,1)--0(0,0) line which probes the lowest lying rotational level of para-H2O. The stronger transitions appear to be optically thick, but reach maximum absorption at a depth of about 25%, suggesting that the background source is only partially covered by the absorbing gas, or that the absorption arises within the 6 micron emitting photosphere. Assuming a covering fraction of 25%, the H2O column density and rotational temperature that best fit the observed abs...

  13. Analysis and modeling of high temporal resolution spectroscopic observations of flares on AD Leo

    CERN Document Server

    Crespo-Chacon, I; Foing, B H; García-Álvarez, D; López-Santiago, J; Montes, D

    2006-01-01

    We report the results of a high temporal resolution spectroscopic monitoring of the flare star AD Leo. During 4 nights, more than 600 spectra were taken in the optical range using the Isaac Newton Telescope (INT) and the Intermediate Dispersion Spectrograph (IDS). We have observed a large number of short and weak flares occurring very frequently (flare activity > 0.71 hours-1). This is in favour of the very important role that flares can play in stellar coronal heating. The detected flares are non white-light flares and, though most of solar flares belong to this kind, very few such events had been previously observed on stars. The behaviour of different chromospheric lines (Balmer series from H_alpha to H_11, Ca II H & K, Na I D_1 & D_2, He I 4026 AA and He I D_3) has been studied in detail for a total of 14 flares. We have also estimated the physical parameters of the flaring plasma by using a procedure which assumes a simplified slab model of flares. All the obtained physical parameters are consist...

  14. High-resolution HI and CO observations of high-latitude intermediate-velocity clouds

    CERN Document Server

    Röhser, T; Bekhti, N Ben; Winkel, B

    2016-01-01

    Intermediate-velocity clouds (IVCs) are HI halo clouds that are likely related to a Galactic fountain process. In-falling IVCs are candidates for the re-accretion of matter onto the Milky Way. We study the evolution of IVCs at the disk-halo interface, focussing on the transition from atomic to molecular IVCs. We compare an atomic IVC to a molecular IVC and characterise their structural differences in order to investigate how molecular IVCs form high above the Galactic plane. With high-resolution HI observations of the Westerbork Synthesis Radio Telescope and 12CO(1-0) and 13CO(1-0) observations with the IRAM 30m telescope, we analyse the small-scale structures within the two clouds. By correlating HI and far-infrared (FIR) dust continuum emission from the Planck satellite, the distribution of molecular hydrogen (H2) is estimated. We conduct a detailed comparison of the HI, FIR, and CO data and study variations of the $X_\\rm{CO}$ conversion factor. The atomic IVC does not disclose detectable CO emission. The a...

  15. GALEX Observations of Diffuse UV Radiation at High Spatial Resolution from the Sandage Nebulosity

    CERN Document Server

    Sujatha, N V; Karnataki, Abhay; Henry, Richard Conn; Bianchi, Luciana

    2008-01-01

    Using the GALEX ultraviolet imagers we have observed a region of nebulosity first identified as starlight scattered by interstellar dust by Sandage (1976). Apart from airglow and zodiacal emission, we have found a diffuse UV background of between 500 and 800 \\phunit in both the \\galex FUV (1350 -- 1750 \\AA) and NUV (1750 -- 2850 \\AA). Of this emission, up to 250 \\phunit is due to \\htwo fluorescent emission in the FUV band; the remainder is consistent with scattering from interstellar dust. We have estimated the optical constants to be $a = 0.3; g = 0.7$ in the FUV and $a = 0.5; g = 0.7$ in the NUV, implying highly forward scattering grains, plus an extragalactic contribution of as much as 150 \\phunit. These are the highest spatial resolution observations of the diffuse UV background to date and show an intrinsic scatter beyond that expected from instrumental noise alone. Further modeling is required to understand the nature of this scatter and its implications for the ISM.

  16. High resolution near-bed observations in winter near Cape Hatteras, North Carolina

    Science.gov (United States)

    Martini, M.; Armstrong, B.; Warner, J.C.

    2009-01-01

    The U.S. Geological Survey (USGS) Coastal and Marine Science Center in Woods Hole, Massachusetts, is leading an effort to understand the regional sediment dynamics along the coastline of North and South Carolina. As part of the Carolinas Coastal Change Processes Project, a geologic framework study in June of 2008 by the Woods Hole Coastal and Marine Science Center's Sea Floor Mapping Group focused on the seaward limit of Diamond Shoals and provided high resolution bathymetric data, surficial sediment characteristics, and subsurface geologic stratigraphy. These data also provided unprecedented guidance to identify deployment locations for tripods and moorings to investigate the processes that control sediment transport at Diamond Shoals. Equipment was deployed at three sites from early January, 2009 through early May, 2009: north and south of the shoals at 15 m depth, and at the tip at 24 m depth. Many strong storm systems were recorded during that time period. Mounted on the tripods were instruments to measure surface waves, pressure, current velocity, bottom turbulence, suspended-sediment profiles, and sea-floor sand-ripple bedforms. Many instruments were designed and programmed to sample in high resolution in time and space, as fast as 8 Hz hourly bursts and as small as 6 cm bin sizes in near bottom profiles. A second tripod at the north site also held a visual camera system and sonar imaging system which document seafloor bedforms. The region is known for its dynamics, and one of the tripods tipped over towards the end of the experiment. A preliminary look at the data suggests the region is characterized by high energy. Raw data from a burst recorded at the south site on Mar. 26th show instantaneous flow speed at 150 cm/s at 0.5 m above the seabed. This paper reports preliminary highlights of the observations, based on raw data, and lessons learned from a deployment of large tripod systems in such a dynamic location. ??2009 MTS.

  17. High spatial resolution 100 micron observations of the M83 bar

    Science.gov (United States)

    Smith, B. J.; Lester, Dan F.; Harvey, P. M.

    1990-01-01

    A program of high spatial resolution far-infrared observations of galaxies using the Kuiper Airborne Observatory (KAO), was conducted to better understand the role of star formation, the general interstellar radiation field, and non-thermal activity in powering the prodigious far-infrared luminosities seen in spiral and interacting galaxies. Here, researchers present observations of the central region of the well-known barred spiral M83 (NGC 5236). The resultant channel 3 scans for M83 and IRC + 10216, after co-addition and smoothing, are shown. These data show that M83 is extended at 100 microns compared to a point source. A simple Gaussian deconvolution of the M83 data with the point source profile from IRC+10216 gives a full width half maximum (FWHM) of about 19 seconds for M83. By comparison with IRC+10216, researchers obtain a flux for the unresolved component in M83 of about 110 Jy. This is about 1/6 the total flux for M83 (Rice et al. 1988) and about 1/2 the PSC flux. The M83 and IRC+10216 profiles in the cross-scan direction (SE-NW) were also compared, and show that M83 is extended in this direction as well, with a width of about 18 seconds. A comparison of the different channel profiles for M83 and IRC+10216 shows that there is an asymmetry in the M83 data, in that the maximum in the profiles shifts from southeast to northwest as channel number increases. This corresponds to the extension in the bar seen in the CO data. Thus the far-infrared emission in the central region of M83 tends to trace the CO bar. The new 100 micron data is also compared with previous H alpha observations from the literature, to determine how well the far-infrared traces the stellar structure, the star formation as measured by H alpha, and the optical colors.

  18. High-resolution regional gravity field recovery from Poisson wavelets using heterogeneous observational techniques

    Science.gov (United States)

    Wu, Yihao; Luo, Zhicai; Chen, Wu; Chen, Yongqi

    2017-02-01

    We adopt Poisson wavelets for regional gravity field recovery using data acquired from various observational techniques; the method combines data of different spatial resolutions and coverage, and various spectral contents and noise levels. For managing the ill-conditioned system, the performances of the zero- and first-order Tikhonov regularization approaches are investigated. Moreover, a direct approach is proposed to properly combine Global Positioning System (GPS)/leveling data with the gravimetric quasi-geoid/geoid, where GPS/leveling data are treated as an additional observation group to form a new functional model. In this manner, the quasi-geoid/geoid that fits the local leveling system can be computed in one step, and no post-processing (e.g., corrector surface or least squares collocation) procedures are needed. As a case study, we model a new reference surface over Hong Kong. The results show solutions with first-order regularization are better than those obtained from zero-order regularization, which indicates the former may be more preferable for regional gravity field modeling. The numerical results also demonstrate the gravimetric quasi-geoid/geoid and GPS/leveling data can be combined properly using this direct approach, where no systematic errors exist between these two data sets. A comparison with 61 independent GPS/leveling points shows the accuracy of the new geoid, HKGEOID-2016, is around 1.1 cm. Further evaluation demonstrates the new geoid has improved significantly compared to the original model, HKGEOID-2000, and the standard deviation for the differences between the observed and computed geoidal heights at all GPS/leveling points is reduced from 2.4 to 0.6 cm. Finally, we conclude HKGEOID-2016 can be substituted for HKGEOID-2000 for engineering purposes and geophysical investigations in Hong Kong.

  19. Global mesospheric tidal winds observed by the high resolution Doppler imager on board the upper atmosphere research satellite

    Energy Technology Data Exchange (ETDEWEB)

    Morton, Y.T.; Lieberman, R.S.; Hays, P.B.; Ortland, D.A.; Marshall, A.R.; Wu, D.; Skinner, W.R.; Burrage, M.D.; Gell, D.A.; Yee, J.H.

    1993-06-18

    This paper presents results of mesospheric and lower thermospheric wind tides. The observations come from the high resolution doppler imager (HRDI) on board the upper atmosphere research satellite. From these observations, the authors report the observation of tidal effects on top of the meridonal winds observed in this region. Previous measurements have been mainly limited to radar measurements from fixed ground stations, which do not give consistent results, and do not provide a global picture of the wave structure.

  20. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations

    Science.gov (United States)

    Gao, Wang; Gao, Chengfa; Pan, Shuguo; Wang, Denghui; Deng, Jiadong

    2015-01-01

    The regional constellation of the BeiDou navigation satellite system (BDS) has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK) positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR). We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL) ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2) ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF) strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system. PMID:26528977

  1. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations

    Directory of Open Access Journals (Sweden)

    Wang Gao

    2015-10-01

    Full Text Available The regional constellation of the BeiDou navigation satellite system (BDS has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR. We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2 ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system.

  2. Beyond Chandra (towards the X-ray Surveyor mission): possible solutions for the implementation of very high angular resolution X-ray telescopes in the new millennium based on fused silica segments

    Science.gov (United States)

    Pareschi, G.; Basso, S.; Civitani, M. M.; Ghigo, M.; Parodi, G.; Pelliciari, C.; Salmaso, B.; Spiga, D.; Vecchi, G.

    2016-07-01

    An important challenge for the X-ray astronomy of the new millennium is represented by the implementation of an Xray telescope able to maintain the exquisite angular resolution of Chandra (with a sub-arcsec HEW, on-axis) but, at the same time, being characterized by a much larger throughput and grasp. A mission with similar characteristics is represented by the X-ray Surveyor Mission. The project has been recently proposed in USA and is being currently studied by NASA. It will host an X-ray telescope with an effective area of more than 2 square meters at 1 keV (i.e. 30 times greater than Chandra) and a 15-arcminutes field-of-view, with 1-arcsecond or better half-power diameter (versus the 4 arcmin diameter of Chandra). While the scientific reasons for implementing a similar mission are clear, being related to compelling problems like e.g. the formation and subsequent growth of black hole seeds at very high redshift or the identification of the first galaxy groups and proto-clusters, the realization of a grazing-angle optics system able to fulfil these specs remain highly challenging. Different technologies are being envisaged, like e.g. the use of adjustable segmented mirrors (with use of piezoelectric or magneto-restrictive film actuators on the back surface) or the direct polishing of a variety of thin substrates or the use of innovative correction methods like e.g. differential deposition, ionfiguring or the correction of the profile via controlled stress films. In this paper we present a possible approach based on the direct polishing (with final ion figuring correction of the profile) of thin SiO2 segmented substrates (typically 2 mm thick), discussing different aspects of the technology under implementation and presenting some preliminary results.

  3. High Resolution HC3N Observations toward the Central Region of Sagittarius B2

    Science.gov (United States)

    Chung, Hyun Soo; Ohishi, Masatoshi; Morimoto, Masaki

    1994-04-01

    We have observed the emission of HC3N J=4-3, 5-4, 10-9 and 12-11 transitions toward the Sgr B2 central region in an area of 150"*150" with resolution of 16"-48". The intensities and central velocities of line profiles show significant variations with positions. In contrast to the intensities of the low J-level transitions which gradually increase from the central source toward the outside region, the HC3N emission of the high J-level transition become stronger toward the central radio continuum source MD5. Systematic change in the radial velocity of each line profile occurs along north-south direction. There are a few peaks in most line profiles, and these indicate that there are multiple velocity components along the line of sight. Distributions of excitation temperature and column density which were estimated from the excitation calculations show the existence of a small(1*2pc), hot(Tex > 50K) core which contains two temperature peaks at about 15" east and north of MD5. The column density of HC3N is (1-3)*10E14 /cm2. Column density at distant position from MD5 is larger than that in the central region. We have deduced that this 'hot-core' has a mass of 10E5 Mo, which is about an order of magnitude larger than those obtained by previous studies.

  4. A high-resolution spectropolarimetric survey of Herbig Ae/Be stars - I. Observations and measurements

    CERN Document Server

    Alecian, E; Catala, C; Grunhut, J H; Landstreet, J D; Bagnulo, S; Böhm, T; Folsom, C P; Marsden, S; Waite, I

    2012-01-01

    This is the first in a series of papers in which we describe and report the analysis of a large survey of Herbig Ae/Be stars in circular spectropolarimetry. Using the ESPaDOnS and Narval high-resolution spectropolarimeters at the Canada-France-Hawaii and Bernard Lyot Telescopes, respectively, we have acquired 132 circularly-polarised spectra of 70 Herbig Ae/Be stars and Herbig candidates. The large majority of these spectra are characterised by a resolving power of about 65,000, and a spectral coverage from about 3700 ang to 1 micron. The peak SNR per CCD pixel ranges from below 100 (for the faintest targets) to over 1000 (for the brightest). The observations were acquired with the primary aim of searching for magnetic fields in these objects. However, our spectra are suitable for a variety of other important measurements, including rotational properties, variability, binarity, chemical abundances, circumstellar environment conditions and structure, etc. In this first paper, we describe the sample selection, ...

  5. The Appearance of Spicules in High Resolution Observations of Ca II H and H-alpha

    CERN Document Server

    Pereira, Tiago M D; Carlsson, Mats

    2016-01-01

    Solar spicules are chromospheric fibrils that appear everywhere on the Sun, yet their origin is not understood. Using high resolution observations of spicules obtained with the Swedish 1-m Solar Telescope we aim to understand how spicules appear in filtergrams and Dopplergrams, how they compare in Ca II H and H-alpha, and what can make them appear and disappear. We find spicules display a rich and detailed spatial structure, and show a distribution of transverse velocities that when aligned with the line of sight can make them appear at different H-alpha wing positions. They become more abundant at positions closer to the line core, reflecting a distribution of Doppler shifts and widths. In H-alpha width maps they stand out as bright features both on disk and off-limb, reflecting their large Doppler motions and possibly higher temperatures than in the typical H-alpha formation region. Spicule lifetimes measured from narrowband images at only a few positions will be an underestimate because Doppler shifts can ...

  6. The Appearance of Spicules in High Resolution Observations of Ca II H and Hα

    Science.gov (United States)

    Pereira, Tiago M. D.; Rouppe van der Voort, Luc; Carlsson, Mats

    2016-06-01

    Solar spicules are chromospheric fibrils that appear everywhere on the Sun, yet their origin is not understood. Using high resolution observations of spicules obtained with the Swedish 1 m Solar Telescope, we aim to understand how spicules appear in filtergrams and Dopplergrams, how they compare in Ca ii H and Hα filtergrams, and what can make them appear and disappear. We find that spicules display a rich and detailed spatial structure, and show a distribution of transverse velocities that, when aligned with the line of sight, can make them appear at different Hα wing positions. They become more abundant at positions closer to the line core, reflecting a distribution of Doppler shifts and widths. In Hα width maps they stand out as bright features both on disk and off limb, reflecting their large Doppler motions and possibly higher temperatures than in the typical Hα formation region. Spicule lifetimes measured from narrowband images at only a few positions will be an underestimate because Doppler shifts can make them disappear prematurely from such images; for such cases, width maps are a more robust tool. In Hα and Ca ii H filtergrams, off-limb spicules essentially have the same properties, appearance, and evolution. We find that the sudden appearance of spicules can be explained by Doppler shifts from their transverse motions, and does not require other convoluted explanations.

  7. Development of a high-spectral-resolution lidar for continuous observation of aerosols in South America

    Science.gov (United States)

    Jin, Yoshitaka; Sugimoto, Nobuo; Nishizawa, Tomoaki; Ristori, Pablo; Papandrea, Sebastian; Otero, Lidia; Quel, Eduardo; Mizuno, Akira

    2016-05-01

    Continuous monitoring of aerosol profiles using lidar is helpful for a quasi-real-time indication of aerosol concentration. For instance, volcanic ash concentration and its height distribution are essential information for plane flights. Depolarization ratio and multi-wavelength measurements are useful for characterizing aerosol types such as volcanic ash, smoke, dust, sea-salt, and air pollution aerosols. High spectral resolution lidar (HSRL) and Raman scattering lidar can contribute to such aerosol characterization significantly since extinction coefficients can be measured independently from backscattering coefficients. In particular, HSRL can measure aerosol extinction during daytime and nighttime with a high sensitivity. We developed an HSRL with the iodine filter method for continuous observation of aerosols at 532nm in the northern region of Argentina in the framework of the South American Environmental Atmospheric Risk Management Network (SAVER.Net)/SATREPS project. The laser wavelength of the HSRL was controlled by a feedback system to tune the laser wavelength to the center of an iodine absorption line. The stability of the laser wavelength with the system satisfied the requirement showing very small systematic errors in the retrieval of extinction and backscatter.

  8. A giant quiescent solar filament observed with high-resolution spectroscopy

    CERN Document Server

    Kuckein, C; Denker, C

    2016-01-01

    A giant, quiet-Sun filament was observed with the high-resolution Echelle spectrograph at the Vacuum Tower Telescope at Observatorio del Teide on 2011 November 15. A mosaic of spectra (10 maps of 100" X 182") was recorded simultaneously in the chromospheric absorption lines H-alpha and Na I D2. Physical parameters of the filament plasma were derived using Cloud Model (CM) inversions and line core fits. The spectra were complemented with full-disk filtergrams (He I 10830 A, H-alpha, and Ca II K) of the Chromspheric Telescope (ChroTel) and full-disk magnetograms of HMI. The filament had extremely large linear dimensions (817"), which corresponds to about 658 Mm along a great circle on the solar surface. A total amount of 175119 H-alpha contrast profiles were inverted using the CM approach. The inferred mean line-of-sight (LOS) velocity, Doppler width, and source function were similar to previous works of smaller quiescent filaments. However, the derived optical thickness was larger. LOS velocity trends inferred...

  9. Spitzer/infrared spectrograph investigation of MIPSGAL 24 {\\mu}m compact bubbles : Low resolution observations

    CERN Document Server

    Nowak, M; Noriega-Crespo, A; Billot, N; Carey, S J; Paladini, R; Van Dyk, S D

    2014-01-01

    We present Spitzer/IRS low resolution observations of 11 compact circumstellar bubbles from the MIPSGAL 24 {\\mu}m Galactic Plane Survey. We find that this set of MIPSGAL bubbles (MBs) is divided into two categories, and that this distinction correlates with the morphologies of the MBs in the mid- IR. The four MBs with central sources in the mid-IR exhibit dust-rich, low excitation spectra, and their 24 {\\mu}m emission is accounted for by the dust continuum. The seven MBs without central sources in the mid-IR have spectra dominated by high excitation gas lines (e.g., [O IV] 26.0 {\\mu}m, [Ne V] 14.3 and 24.3 {\\mu}m, [Ne III] 15.5 {\\mu}m), and the [O IV] line accounts for 50 to almost 100% of the 24 {\\mu}m emission in five of them. In the dust-poor MBs, the [Ne V] and [Ne III] line ratios correspond to high excitation conditions. Based on comparisons with published IRS spectra, we suggest that the dust-poor MBs are highly excited planetary nebulae with peculiar white dwarfs (e.g., [WR], novae) at their centers. ...

  10. Radiofrequency encoded angular-resolved light scattering

    DEFF Research Database (Denmark)

    Buckley, Brandon W.; Akbari, Najva; Diebold, Eric D.

    2015-01-01

    The sensitive, specific, and label-free classification of microscopic cells and organisms is one of the outstanding problems in biology. Today, instruments such as the flow cytometer use a combination of light scatter measurements at two distinct angles to infer the size and internal complexity...... of cells at rates of more than 10,000 per second. However, by examining the entire angular light scattering spectrum it is possible to classify cells with higher resolution and specificity. Current approaches to performing these angular spectrum measurements all have significant throughput limitations...... Encoded Angular-resolved Light Scattering (REALS), this technique multiplexes angular light scattering in the radiofrequency domain, such that a single photodetector captures the entire scattering spectrum from a particle over approximately 100 discrete incident angles on a single shot basis. As a proof...

  11. Clumpy galaxies seen in H-alpha: inflated observed clump properties due to limited spatial resolution and sensitivity

    CERN Document Server

    Tamburello, Valentina; Mayer, Lucio; Cava, Antonio; Dessauges-Zavadsky, Miroslava; Schaerer, Daniel

    2016-01-01

    High-resolution simulations of star-forming massive galactic discs have shown that clumps form with a characteristic baryonic mass in the range $10^7-10^8~M_{\\odot}$, with a small tail exceeding $10^9~M_{\\odot}$ produced by clump-clump mergers. This is in contrast with the observed kpc-size clumps with masses up to $10^{10}~M_{\\odot}$ in high-redshift star-forming galaxies. In this paper we show that the comparison between simulated and observed star-forming clumps is hindered by limited observational spatial resolution and sensitivity. We post-process high-resolution hydrodynamical simulations of clumpy discs using accurate radiative transfer to model the effect of ionizing radiation from young stars and to compute H$\\alpha$ emission maps. By comparing the intrinsic clump size and mass distributions with those inferred from convolving the H$\\alpha$ maps with different gaussian apertures, we mimick the typical resolution used in observations. We found that with 100 pc resolution, mock observations can recover...

  12. CHANDRA HIGH-RESOLUTION OBSERVATIONS OF CID-42, A CANDIDATE RECOILING SUPERMASSIVE BLACK HOLE

    Energy Technology Data Exchange (ETDEWEB)

    Civano, F.; Elvis, M.; Lanzuisi, G.; Aldcroft, T.; Trichas, M.; Fruscione, A. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Bongiorno, A.; Brusa, M. [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching (Germany); Blecha, L.; Loeb, A. [Department of Astronomy, Harvard University, 60 Garden Street, Cambridge, MA 02138 (United States); Comastri, A.; Gilli, R. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, Bologna 40127 (Italy); Salvato, M.; Komossa, S. [Max-Planck-Institute for Plasma Physics, Excellence Cluster, Boltzmannstrass 2, 85748 Garching (Germany); Koekemoer, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Mainieri, V. [ESO, Karl-Schwarzschild-Strasse 2, 85748 Garching (Germany); Piconcelli, E. [INAF-Osservatorio Astronomico di Roma, Via Frascati 33, Monteporzio-Catone 00040 (Italy); Vignali, C. [Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, Bologna 40127 (Italy)

    2012-06-10

    We present Chandra High Resolution Camera observations of CID-42, a candidate recoiling supermassive black hole (SMBH) at z = 0.359 in the COSMOS survey. CID-42 shows two optical compact sources resolved in the HST/ACS image embedded in the same galaxy structure and a velocity offset of {approx}1300 km s{sup -1} between the H{beta} broad and narrow emission line, as presented by Civano et al. Two scenarios have been proposed to explain the properties of CID-42: a gravitational wave (GW) recoiling SMBH and a double Type 1/Type 2 active galactic nucleus (AGN) system, where one of the two is recoiling because of slingshot effect. In both scenarios, one of the optical nuclei hosts an unobscured AGN, while the other one, either an obscured AGN or a star-forming compact region. The X-ray Chandra data allow us to unambiguously resolve the X-ray emission and unveil the nature of the two optical sources in CID-42. We find that only one of the optical nuclei is responsible for the whole X-ray unobscured emission observed and a 3{sigma} upper limit on the flux of the second optical nucleus is measured. The upper limit on the X-ray luminosity plus the analysis of the multiwavelength spectral energy distribution indicate the presence of a star-forming region in the second source rather than an obscured SMBH, thus favoring the GW recoil scenario. However, the presence of a very obscured SMBH cannot be fully ruled out. A new X-ray feature, in a SW direction with respect to the main source, is discovered and discussed.

  13. High spectral resolution observation of extended sources in future interplanetary missions

    Science.gov (United States)

    Hosseini, Sona

    2016-10-01

    The most commonly used technique for high spectral resolution (R) studies are grating spectrometers. They can achieve broad bandpasses but they have small FOV and relatively low étendue so they have to be paired with large aperture telescopes such Keck (10m), Hubble (2.4m) or JWST (6.5m). Fabry-Pérot Interferometers (FPI) and FTS are the other best known types of high étendue, high R spectrometers used in astronomy. But their opto-mechnical tolerances becomes challenging and they use transmitting optics, where transmission drops especially below 130 nm. Spatial Heterodyne Spectrometer (SHS) is a candidate for high étendue, high spectral R spectroscopy in compact low cost, low-mass, low-power architecture using no or small aperture telescope for UV to IR wavelengths. High R spectrometers are usually limited by the telescope aperture size and complicated opto-mechanical tolerances but that's not the case for SHS. SHS provides integrated spectra at high spectral R, over a wide FOV in compact designs in which it offers the ability to make key science measurements for a variety of planetary targets. SHS could be implemented on a dedicated SmallSat or ISS that can sit and stare at its target for long duration of time that cannot be done from the ground or on big missions. SmallSats are lower cost, faster to build, relatively easy to correct and upgrade. For UV observation, currently HST is the only telescope capable of collecting the necessary observations and the next major UV space telescope might be able to fly in 10 years or more. SHS instrument can quickly fill the technology gap for UV space spectrometers.

  14. The spatial resolutions of the apposition compound eye and its neuro-sensory feature detectors: observation versus theory.

    Science.gov (United States)

    Horridge, Adrian

    2005-03-01

    For 100 years three ideas dominated efforts to understand the apposition compound eye. In Müller's theory, the eye viewed the panorama through an array of little windows without overlaps and without gaps, with no details within windows. Spatial resolution then depended on the interommatidial angle (Deltaphi) and the number of ommatidia. In the second proposal, the insect detected the temporal modulation of the light, which was limited by the aperture of the lens and the wavelength, assuming good focus. Modulation is the change of intensity in the receptor, usually caused by motion of a spatial contrast in the stimulus. Thirdly, motion was detected from the successive temporal modulations at adjacent visual axes. Recently, two more principles arose. The light-sensitive elements, called rhabdomeres, project through the nodal point of the lens to the outside world, and the resolution was limited by their grain size, like the pixels in a digital camera. Finally, detection of contrast and colour was limited by the signal/noise ratio (SNR) which was improved by brighter light and more visual pigment. These five physical principles provide satisfying explanations of eye function but they all originated from theory. Actual measurements of resolution depend on the operation of the test. The visual system of the honeybee recognizes a limited variety of simple cues, but there is no evidence that the pattern of ommatidial stimulation is re-assembled, or even seen. The known cues are: the temporal modulation of groups of receptors, the direction and angular velocity of motion, some measure of the spatial disruption of the pattern or the length of edge (related to spatial frequency and contrast), colour, the intensity, the position of the centre and the size of large well-separated areas of black or colour, the angle of orientation of a bar or grating, radial or tangential edges, and bilateral symmetry. Neurons connected to more than two adjacent ommatidia collaborate in the

  15. High-Resolution Transmission Electron Microscopy Observation of Colloidal Nanocrystal Growth Mechanisms using Graphene Liquid Cells

    Energy Technology Data Exchange (ETDEWEB)

    Yuk, Jong Min; Park, Jungwon; Ercius, Peter; Kim, Kwanpyo; Hellebusch, Danny J.; Crommie, Michael F.; Lee, Jeong Yong; Zettl, A.; Alivisatos, A. Paul

    2011-12-12

    We introduce a new type of liquid cell for in-situ electron microscopy based upon entrapment of a liquid film between layers of graphene. We employ this cell to achieve high-resolution imaging of colloidal platinum nanocrystal growth. The ability to directly image and resolve critical steps at atomic resolution provides new insights into nanocrystal coalescence and reshaping during growth.

  16. An advanced high resolution x-ray imager for laser-plasma interaction observation

    Directory of Open Access Journals (Sweden)

    Dennetiere D.

    2013-11-01

    Full Text Available We present here the latest results obtained with our high resolution broadband X-ray microscope. These results, both spatial and spectral, were obtained in several facilities such as Berlin's synchrotron Bessy II and LULI's laser ELFIE 100TW. The results show clearly the opportunity in high resolution microscopy that offer mirror based diagnostics.

  17. Transverse and longitudinal angular momenta of light

    Energy Technology Data Exchange (ETDEWEB)

    Bliokh, Konstantin Y., E-mail: k.bliokh@gmail.com [Center for Emergent Matter Science, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Nonlinear Physics Centre, RSPhysE, The Australian National University, Canberra, ACT 0200 (Australia); Nori, Franco [Center for Emergent Matter Science, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Physics Department, University of Michigan, Ann Arbor, MI 48109-1040 (United States)

    2015-08-26

    We review basic physics and novel types of optical angular momentum. We start with a theoretical overview of momentum and angular momentum properties of generic optical fields, and discuss methods for their experimental measurements. In particular, we describe the well-known longitudinal (i.e., aligned with the mean momentum) spin and orbital angular momenta in polarized vortex beams. Then, we focus on the transverse (i.e., orthogonal to the mean momentum) spin and orbital angular momenta, which were recently actively discussed in theory and observed in experiments. First, the recently-discovered transverse spin  angular momenta appear in various structured fields: evanescent waves, interference fields, and focused beams. We show that there are several kinds of transverse spin angular momentum, which differ strongly in their origins and physical properties. We describe extraordinary features of the transverse optical spins and overview recent experiments. In particular, the helicity-independent transverse spin inherent in edge evanescent waves offers robust spin–direction coupling at optical interfaces (the quantum spin Hall effect of light). Second, we overview the transverse orbital angular momenta of light, which can be both extrinsic and intrinsic. These two types of the transverse orbital angular momentum are produced by spatial shifts of the optical beams (e.g., in the spin Hall effect of light) and their Lorentz boosts, respectively. Our review is underpinned by a unified theory of the angular momentum of light based on the canonical momentum and spin densities, which avoids complications associated with the separation of spin and orbital angular momenta in the Poynting picture. It allows us to construct a comprehensive classification of all known optical angular momenta based on their key parameters and main physical properties.

  18. Quark Orbital Angular Momentum

    Directory of Open Access Journals (Sweden)

    Burkardt Matthias

    2015-01-01

    Full Text Available Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asymmetries in semi-inclusive deep-inelastic scattering.

  19. Monitoring Changes in Water Resources Systems Using High Resolution Satellite Observations: Application to Lake Urmia

    Science.gov (United States)

    Norouzi, H.; AghaKouchak, A.; Madani, K.; Mirchi, A.; Farahmand, A.; Conway, C.

    2013-12-01

    Lake Urmia with its unique ecosystem in northwestern Iran is the second largest saltwater lake in the world. It is home of more than 300 species of birds, reptiles, and mammals with high salinity level of more than 300 g/l. In recent years, a significant water retreat has occurred in this lake. In this study, we tried to monitor the desiccation of the lake over more than four decades using remote sensing observations. Multi-spectral high-resolution LandSat images of the Lake Urmia region from 1972 to 2012 were acquired to derive the lake area. The composite maps of the lake were created, and a Bayesian Maximum Likelihood classification technique was used to classify land and water in the composite maps. The time series of the lake area reveals that it has shrunk by more than 40% in the past ten years. Moreover, water budget related components such as precipitation, soil moisture, and drought indices from remote sensing of the lake basin were utilized to investigate if droughts or climate change are the primary driving forces behind this phenomenon. These analyses show that the retreat of the lake is not related to droughts or global climate change as it has survived several drought events before year 2000. Similar analyses conducted on Lake Van located about 400 km west of Lake Urmia with very similar climate pattern revealed no significant areal change despite the lake's exposure to similar drought events. These results raise serious concern about the destructive role of unbridled development coupled with supply-oriented water management scheme driven by a classic upstream-downstream competition for water in the Lake Urmia region. There is an urgent need to investigate sustainable restoration initiatives for Lake Urmia in order to prevent an environmental disaster comparable to catastrophic death of Aral Sea.

  20. NIOZ high-resolution moored temperature observations: benefits and new challenges.

    Science.gov (United States)

    Cimatoribus, Andrea; Gostiaux, Louis; Cyr, Frederic; van Haren, Hans

    2016-04-01

    The Royal Netherlands Institute for Sea Research has been developing for several years a family of temperature sensors (NIOZ1 to NIOZ5). In the latest iterations of this project, these instruments are precise (10-3 K or better), have a very low noise level (below 10-3 K), are relatively fast (sampling rate of 1Hz) and can measure for extended periods of time (several months). Being also compact and lightweight, several thermistors can be attached on a single line at a fine vertical spacing (20cm or more). When mounted on a cable, the instruments are all synchronised to a single clock, thus providing simultaneous measurements throughout the depth range of the mooring (usually in the order of 100m). Recently, the instruments have also been deployed in a group of 5 lines approximately 5m apart from each other, providing a unique view on the three-dimensional temperature field. After almost 10 years of successful deployments at sea, we try to draw some conclusions from this effort, from the scientific and technical point of view. This observational system provides temperature measurements with vertical spatial resolution comparable to that of microstructure profilers, but in comparison to ship-borne systems it offers some distinctive features: providing instantaneous measurements throughout the mooring, observations of waves and overturning structures are not influenced by the time delay between measurements at different depths; the very low noise level and high precision enables the study of the deep, weakly stratified ocean; by using a heavy ballast at the bottom and a high net buoyancy at the top of the mooring, Eulerian measurements are effectively obtained; continuous, high sampling rate Eulerian measurements enable to assess the intermittent, sporadic nature of turbulence and wave activity in the ocean; the large range of time scales included in the observations (100 - 106 s) allows to study a large portion of the turbulence inertial range, the full internal wave

  1. [Malignant angular cheilitis].

    Science.gov (United States)

    Seoane, J; Vázquez, J; Cazenave, A; de la Cruz Mera, A; Argila, F; Aguado, A

    1996-01-01

    A case of chronic angular cheilitis is reported. Candida albicans was isolated repeatedly and the process developed into epitheliomatous carcinoma. The etiopathogenic role of Candida albicans and possible mechanism of action are discussed.

  2. Angular Cheilitis Pada Anak

    OpenAIRE

    Gema Nazriyanti

    2008-01-01

    Angular cheilitis adalah inflamasi akut atau kronis pada sudut mulut yang ditandai dengan adanya flsur-fisur, retak-retak pada sudut bibir, berwarna kemerahan, mengalami ulserasi disertai rasa terbakar, nyeri dan rasa kering pada sudut mulut. Dapat mengenai orang tua, dewasa dan anak-anak. Banyak pendapat yang mengemukakan tentang etiologi dari angular cheilitis, antara lain defisiensi vitamin B kompleks, denture soremouth, defisiensi besi, kebiasaan bernafas melalui mulut, membasahi bib...

  3. Mirror-concentrator for space telescope with wide field of view and "high" angular resolution for observation of ultrahigh energy cosmic rays and other atmospheric flashes

    Science.gov (United States)

    Sharakin, Sergey A.; Khrenov, Boris A.; Klimov, Pavel A.; Panasyuk, Mikhail I.; Potanin, Sergey A.; Yashin, Ivan V.

    2012-09-01

    Idea of ultrahigh cosmic rays (UHECR) measurement from satellites was suggested by Linsley in 1981 and since has being developed into projects of cosmic rays telescopes for International Space Station (ISS): JEM-EUSO - to be installed on the Japanese experimental module and KLYPVE - on the Russian ISS segment. A series of space-based detectors for measurements of background phenomena in those telescopes were developed in Russia (Universitetsky-Tatiana, Universitetsky-Tatiana-2 , Chibis satellites). The satellite Lomonosov with UHECR detector TUS on its board will be launched in 2013. TUS contains multi-channel photo receiver and Fresnel-type mirror manufactured with use of special multi-layer carbon plastic technology in RSC “Energia". In this paper one and two component optical systems with 360 cm entrance diameter and 400 cm focal distance for wide angle detector KLYPVE are studied. In one component case using generalized Davies-Cotton systems (Fresnel-type mirror with ellipsoidal gross surface) it is possible to obtain 8-10° field of view (FoV) with focal spot size less than pixel size equal to 15 x 15 mm. In two component system (parabolic mirror and a Fresnel lens, mounted close to photo receiver) it is possible to increase FoV up to 10-12° and significantly simplify the primary mirror construction.

  4. Probing Our Heliospheric History I: High-Resolution Observations of Na I and Ca II Along the Solar Historical Trajectory

    CERN Document Server

    Wyman, Katherine

    2013-01-01

    Over the course of its motion through the Galaxy, our solar system has encountered many interstellar environments of varying characteristics. Interstellar medium (ISM) density variations spanning seven orders of magnitude are commonly seen throughout the general Galactic environment, and a sufficiently dense cloud within this range has the potential to dramatically alter the structure of the heliosphere. We present observations of the ISM environments the Sun has most recently encountered based on high-resolution optical spectra toward nearby stars in the direction of the historical solar trajectory. The data were obtained with the highest-resolution spectrographs available, including the Tull Spectrograph on the Harlan J. Smith Telescope at McDonald Observatory and the Ultra-High-Resolution Facility on the Anglo-Australian Telescope at the Anglo-Australian Observatory. Observations were made of interstellar Na I and Ca II doublet absorption toward 43 bright stars within about 500 pc. No absorption is seen ou...

  5. Contribution of High Resolution Microwave and Optical Remote Sensing Observations in Detecting and Monitoring Ocean Coastal Features

    Science.gov (United States)

    Gagliardini, D. A.

    Synthetic Aperture Radar SAR satellite sensors have demonstrated their ability to observe ocean features related to dynamical processes Because of the high resolution of available SAR sensors circulation details and small-scale processes can be detected that are not observable by other sensors more frequently used for ocean research such as the NOAA AVHRR and the ORBVIEW2 SeaWiFS In contrast to these LANDSAT-TM thermal and optical channels can be used to observe sea surface temperatures surface layer ocean color upwelled radiance as well as sun glint reflected radiance patterns of surface roughness at a spatial resolution comparable to that of SAR Several examples of TM images obtained in 1997-2003 over the Argentine coastal ocean region where selected from an extensive data set These images were analyzed and compared with a series of SAR images acquired over the same region by the ERS satellites and in some cases near coincident with the TM data This time period allowed the examination of the seasonal cycles as well as interesting episodic events of different ocean processes including currents fronts upwellings algal blooms eddies internal waves and bathymetry signatures Due in situ observations are scarce over this region some of these processes have been documented for first time helping to improve our understanding of some dynamical and biological aspects Therefore it can be concluded that high resolution optical thermal and microwave data have the ability of providing consistent and complementary high-resolution

  6. Observation of Kondo resonance in rare-earth hexaborides using high resolution photoemission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Kalobaran; Patil, Swapnil; Adhikary, Ganesh [Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India); Balakrishnan, Geetha, E-mail: kbmaiti@tifr.res.in [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom)

    2011-01-01

    We studied the electronic structure of rare earth hexaborides, CeB{sub 6}, PrB{sub 6} and NdB{sub 6} using state-of-the-art high resolution photoemission spectroscopy. CeB{sub 6} is a dense Kondo system. PrB{sub 6} and NdB{sub 6} are antiferromagnetic (Neel temperature {approx}7 K), known to be stable moment systems and do not exhibit Kondo effect. Photoemission spectra exhibit distinct signature of surface and bulk electronic structures of these compounds. The energy position of the surface feature is not influenced by the 4f density of states. High resolution spectra of CeB{sub 6} reveal multiple Kondo resonance features in the bulk spectra due to various photoemission final states. Interestingly, high resolution photoemission spectra of antiferromagnetic PrB{sub 6} also exhibit a sharp feature at the Fermi level that shows temperature dependence similar to the Kondo resonance features.

  7. Vibronic motion with joint angstrom-femtosecond resolution observed through Fano progressions recorded within one molecule.

    Science.gov (United States)

    Lee, Joonhee; Perdue, Shawn M; Rodriguez Perez, Alejandro; Apkarian, Vartkess Ara

    2014-01-28

    Electroluminescence (EL) in scanning tunneling microscopy (STM), which enables spectroscopy with submolecular spatial resolution, is shown to be due to radiative ionization with vibronic shape resonances that carry Fano line profiles. Since Fano progressions retain phase information, the spectra can be transformed to the time domain to reconstruct the vibronic motion. In effect, measurements within a molecule are accessible with joint space-time resolution at the Å-fs limit. We demonstrate this through EL-STM on the Jahn-Teller-active Zn-etioporphyrin radical anion and visualize the orbiting motion of scattered electrons upon sudden reduction and oxidation. We discuss the elements that enable spectroscopy with submolecular spatial resolution through EL-STM and the closely related STM-Raman process.

  8. The surface layer observed by a high-resolution sodar at DOME C, Antarctica

    Directory of Open Access Journals (Sweden)

    Stefania Argentini

    2014-01-01

    Full Text Available One year field experiment has started on December 2011 at the French - Italian station of Concordia at Dome C, East Antarctic Plateau. The objective of the experiment is the study of the surface layer turbulent processes under stable/very stable stratifications, and the mechanisms leading to the formation of the warming events. A sodar was improved to achieve the vertical/time resolution needed to study these processes. The system, named Surface Layer sodar (SL-sodar, may operate both in high vertical resolution (low range and low vertical resolution (high range modes. In situ turbulence and radiation measurements were also provided in the framework of this experiment. A few preliminary results, concerning the standard summer diurnal cycle, a summer warming event, and unusually high frequency boundary layer atmospheric gravity waves are presented.

  9. Creation of a high resolution precipitation data set by merging gridded gauge data and radar observations for Sweden

    Science.gov (United States)

    Berg, Peter; Norin, Lars; Olsson, Jonas

    2016-10-01

    Hydrological forecasting systems require accurate initial conditions, particularly for real time precipitation data, which are problematic to retrieve. This is especially difficult for high temporal and spatial resolutions, e.g. sub-daily and less than 10-20 km. Forecasting fast processes such as flash flood are, however, dependent on such high resolution data. Gridded gauge data produces too smooth fields and underestimates small scale phenomena, such as convection, whereas radar composites contain the small scale information, but suffer from inconsistencies between individual radars and have poor long term statistics. Here, we present a method to merge a radar composite with daily resolution gridded gauge data for Sweden for the time period 2009-2014 to produce a one hourly 4 × 4 km2 data set. The method consists of a main step where monthly accumulations of the radar data are scaled by those retrieved from the gridded data for each month. An optional quantile mapping based bias correction step makes sure that the daily intensity distribution agrees with the gridded observations. Finally, the data are dis-aggregated to an hourly time resolution. This results in a data set which has the same long-term spatial properties as the gridded observations, but with the spatial and temporal details of the radar data. Validation of the method is performed with high resolution gauge data, and shows a high quality of the derived product.

  10. Evaluation on newly developed high resolution of surface solar radiation from MTSAT observations for the Tibetan Plateau

    Science.gov (United States)

    Niu, X.; Yang, K.; Tang, W.; Qin, J.

    2015-12-01

    Neither surface measurement nor existing remote sensing products of the Surface Solar Radiation (SSR) can meet the application requirements of hydrological and land process modeling in the Tibetan Plateau (TP). High resolution (hourly; 0.1⁰) of SSR estimates have been derived recently from the geostationary satellite observations - the Multi-functional Transport Satellite (MTSAT). This SSR estimation is based on updating an existing physical model, the UMD-SRB (University of Maryland Surface Radiation Budget) which is the basis of the well-known GEWEX-SRB model. In the updated framework introduced is the high-resolution Global Land Surface Broadband Albedo Product (GLASS) with spatial continuity. The developed SSR estimates are demonstrated at different temporal resolutions over the TP and are evaluated against ground observations and other satellite products from: (1) China Meteorological Administration (CMA) radiation stations in TP; (2) three TP radiation stations contributed from the Institute of Tibetan Plateau Research; (3) and the universal used satellite products (i.e. ISCCP-FD, GEWEX-SRB) in relatively low spatial resolution (0.5º-2.5º) and temporal resolution (3-hourly, daily, or monthly).

  11. Seismic Study of the Subsurface Structure and Dynamics of the Solar Interior from High Spatial Resolution Observations

    Science.gov (United States)

    Korzennik, Sylvain G.

    1997-01-01

    We have carried out the data reduction and analysis of Mt. Wilson 60' solar tower high spatial resolution observations. The reduction of the 100-day-long summer of 1990 observation campaign in terms of rotational splittings was completed leading to an excess of 600,000 splittings. The analysis of these splittings lead to a new inference of the solar internal rotation rate as a function of depth and latitude.

  12. Observation of Tropical Rain Forest Trees by Airborne High-Resolution Interferometric Radar

    NARCIS (Netherlands)

    Hoekman, D.H.; Varekamp, C.

    2001-01-01

    The Indonesian Radar Experiment (INDREX) Campaign was executed in Indonesia to study the potential of high-resolution interferometric airborne radar in support of sustainable tropical forest management. Severe cloud cover limits the use of aerial photography, which is currently applied on a routine

  13. The Liege-balloon program. [balloon-borne instruments for high-spectral resolution observations of the sun

    Science.gov (United States)

    Zander, R.

    1974-01-01

    The Liege-balloon program is intended to make high-spectral resolution observations of the sun in the near- and intermediate infrared regions not accessible from the ground. A description of the equipment, followed by a summary of the data obtained till now is presented. Except for ozone whose maximum of concentration lies near 25 Km altitude, the residual mass distribution of the other mentioned molecules decreases with altitude. This is a self-explanatory argument for carrying out spectroscopic observations from platforms transcending the densest layers of the earth's atmosphere. The Liege balloon equipment is primarily intended for very high-resolution solar observations from about 27-30 Km altitude, in all spectral regions between 1.5 and 15.0 microns, not accessible from the ground.

  14. Features of the Jovian DAM radiation dynamic spectra as observed by modern receivers with high frequency-temporal resolution

    Science.gov (United States)

    Litvinenko, G.; Konovalenko, A.; Zakharenko, V.; Vinogradov, V.; Shaposhnikov, V.; Zarka, Ph.

    2012-09-01

    One of the promising approaches to investigating features of the Jovian decameter radio emission (DAM) is application of novel experimental techniques with a further detailed analysis of the obtained data using both well-known and modern mathematical methods. Several observational campaigns were performed in November 2009 with the use of the UTR-2 radio telescope (Kharkov, Ukraine) and efficient registration systems with high frequency and temporal resolutions (the antenna effective area is about 105 m2, the frequency resolution is 4 kHz, the temporal resolution is 0.25 ms, and the dynamic range is 70 dB) [1]. The main goal of these campaigns was to experimentally investigate new properties of the Jovian DAM emission which could be detected using the above mentioned equipment. Also an original software package was developed for control the digital receiver and for off-line data analysis at the postprocessing stage.

  15. Real-time observation of Zn electro-deposition with high-resolution microradiology

    CERN Document Server

    Tsai, W L; Hwu, Y; Chen, C H; Chang, L W; Je, J H; Margaritondo, G

    2003-01-01

    We used phase contrast radiography to study the electro-deposition of Zn in real time and with high lateral resolution. Using unmonochromatic synchrotron X-rays and an optics-less imaging setup, we were able to obtain real-time radiographs of the electro-deposition in situ with mu m resolution. A detailed analysis of the microstructure evolution relates the different growth parameters - such as the electric current density, the voltage bias, the pH value and the ion concentration - to very different growth morphology, ranging from film, porous, whisker and dendrite deposition. This link is both global and local. Local variations of the metal ion concentration in the electrolyte were also successfully imaged and the density profile is used to compare with the standard theory to explain the phenomenon of metal ion depletion near the electrode. The potential application of this technique to study growth with micropatterned electrodes and pulsed electric current is evaluated.

  16. A High Resolution Spectroscopic Observation of CAL 83 with XMM-Newton/RGS

    CERN Document Server

    Paerels, F B S; Hartmann, H W; Heise, J; Brinkman, A C; De Vries, C P; Den Herder, J M; Paerels, Frits; Rasmussen, Andrew P.

    2001-01-01

    We present the first high resolution photospheric X-ray spectrum of a Supersoft X-ray Source, the famous CAL~83 in the Large Magellanic Cloud. The spectrum was obtained with the Reflection Grating Spectrometer on XMM-Newton during the Calibration/Performance Verification phase of the observatory. The spectrum covers the range 20-40 A at an approximately constant resolution of 0.05 A, and shows very significant, intricate detail, that is very sensitive to the physical properties of the object. We present the results of an initial investigation of the spectrum, from which we draw the conclusion that the spectral structure is probably dominated by numerous absorption features due to transitions in the L-shells of the mid-$Z$ elements and the M-shell of Fe, in addition to a few strong K-shell features due to CNO.

  17. High-resolution observations of the spatial and velocity distribution of cometary hydrogen

    Science.gov (United States)

    Brown, Michael E.; Spinrad, Hyron

    1992-01-01

    We have obtained high velocity and spatial resolution long-slit H alpha spectra of comets Austin (1989c1) and Levy (1990c). Spectra of both comets clearly show the existence of a low velocity thermalized component of hydrogen gas. The amount of slow hydrogen is estimated for comet Austin. The Levy spectrum shows an unusual high-velocity spatially-confined blob of hydrogen emission of unknown origin.

  18. A New Concept of Synthetic Aperture Instrument for High Resolution Earth Observation from High Orbits

    Science.gov (United States)

    2005-07-13

    ces composantes en adoptant une redécomposition des concepts d’interféromètres de type Fizeau ou Michelson . Concept qui autorise, en outre, de rendre le...considering monolithic concepts. It is necessary, to circumvent this problem, to consider a segmented instrument, turning it into a feasible concept...adopting a re-decomposition of the basic Michelson or Fizeau interferometer schemes. In addition to providing variable resolution power and field of

  19. Optical orbital angular momentum

    Science.gov (United States)

    Barnett, Stephen M.; Babiker, Mohamed; Padgett, Miles J.

    2017-01-01

    We present a brief introduction to the orbital angular momentum of light, the subject of our theme issue and, in particular, to the developments in the 13 years following the founding paper by Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)). The papers by our invited authors serve to bring the field up to date and suggest where developments may take us next. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069775

  20. Optical orbital angular momentum

    Science.gov (United States)

    Barnett, Stephen M.; Babiker, Mohamed; Padgett, Miles J.

    2017-02-01

    We present a brief introduction to the orbital angular momentum of light, the subject of our theme issue and, in particular, to the developments in the 13 years following the founding paper by Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)). The papers by our invited authors serve to bring the field up to date and suggest where developments may take us next. This article is part of the themed issue 'Optical orbital angular momentum'.

  1. Improvement of GPS ambiguity resolution using prior height information. Part Ⅱ: The method of using quasi observation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper deals with the method of using quasi observation. In the paper a simple algorithm is developed for the adjustment computation with quasi observation at first. And then the ability of quasi observation to improve ambiguity search technique is studied in detail. The robustness of the method is also discussed. A method to determine the weight of quasi observation is proposed. The results show that a prior height can be taken as a quasi observation and used together with GPS observations. It can strengthen residual tests, especially in situation where there are fewer satellites in the sky. It also can change structure of incorrect solutions, which will theoretically make less incorrect solutions left in search space. At last the field tests are carried out to show that the proposed method is effective. The success rate of ambiguity resolution in the four field tests is improved significantly.

  2. Creating high-harmonic beams with controlled orbital angular momentum.

    Science.gov (United States)

    Gariepy, Genevieve; Leach, Jonathan; Kim, Kyung Taec; Hammond, T J; Frumker, E; Boyd, Robert W; Corkum, P B

    2014-10-10

    A beam with an angular-dependant phase Φ = ℓϕ about the beam axis carries an orbital angular momentum of ℓℏ per photon. Such beams are exploited to provide superresolution in microscopy. Creating extreme ultraviolet or soft-x-ray beams with controllable orbital angular momentum is a critical step towards extending superresolution to much higher spatial resolution. We show that orbital angular momentum is conserved during high-harmonic generation. Experimentally, we use a fundamental beam with |ℓ| = 1 and interferometrically determine that the harmonics each have orbital angular momentum equal to their harmonic number. Theoretically, we show how any small value of orbital angular momentum can be coupled to any harmonic in a controlled manner. Our results open a route to microscopy on the molecular, or even submolecular, scale.

  3. High resolution modelling and observation of wind-driven surface currents in a semi-enclosed estuary

    Science.gov (United States)

    Nash, S.; Hartnett, M.; McKinstry, A.; Ragnoli, E.; Nagle, D.

    2012-04-01

    offline coupling with the wind forecast models. Modelled surface currents show good correlation with CODAR observed currents and the resolution of the surface wind data is shown to be important for model accuracy.

  4. Ghost Imaging Using Orbital Angular Momentum

    Institute of Scientific and Technical Information of China (English)

    赵生妹; 丁建; 董小亮; 郑宝玉

    2011-01-01

    We present a novel encoding scheme in a ghost-imaging system using orbital angular momentum. In the signal arm, object spatial information is encoded as a phase matrix. For an N-grey-scale object, different phase matrices, varying from 0 to K with increment n/N, are used for different greyscales, and then they are modulated to a signal beam by a spatial light modulator. According to the conservation of the orbital angular momentum in the ghost imaging system, these changes will give different coincidence rates in measurement, and hence the object information can be extracted in the idler arm. By simulations and experiments, the results show that our scheme can improve the resolution of the image effectively. Compared with another encoding method using orbital angular momentum, our scheme has a better performance for both characters and the image object.%We present a novel encoding scheme in a ghost-imaging system using orbital angular momentum.In the signal arm,object spatial information is encoded as a phase matrix.For an N-grey-scale object,different phase matrices,varying from 0 to π with increment π/N,are used for different greyscales,and then they are modulated to a signal beam by a spatial light modulator.According to the conservation of the orbital angular momentum in the ghost imaging system,these changes will give different coincidence rates in measurement,and hence the object information can be extracted in the idler arm.By simulations and experiments,the results show that our scheme can improve the resolution of the image effectively.Compared with another encoding method using orbital angular momentum,our scheme has a better performance for both characters and the image object.

  5. Induced Angular Momentum

    Science.gov (United States)

    Parker, G. W.

    1978-01-01

    Discusses, classically and quantum mechanically, the angular momentum induced in the bound motion of an electron by an external magnetic field. Calculates the current density and its magnetic moment, and then uses two methods to solve the first-order perturbation theory equation for the required eigenfunction. (Author/GA)

  6. "Angular" plasma cell cheilitis.

    Science.gov (United States)

    da Cunha Filho, Roberto Rheingantz; Tochetto, Lucas Baldissera; Tochetto, Bruno Baldissera; de Almeida, Hiram Larangeira; Lorencette, Nádia Aparecida; Netto, José Fillus

    2014-03-17

    Plasma cell cheilitis is an extremely rare disease, characterized by erythematous-violaceous, ulcerated and asymptomatic plaques, which evolve slowly. The histological characteristics include dermal infiltrate composed of mature plasmocytes. We report a case of Plasma cell angular cheilitis in a 58-year-old male, localized in the lateral oral commissure.

  7. "Angular" plasma cell cheilitis

    OpenAIRE

    da Cunha Filho, Roberto Rheingantz; Tochetto, Lucas Baldissera; Tochetto, Bruno Baldissera; de Almeida Jr, Hiram Larangeira; Lorencette, Nadia Aparecida; Netto, Jose Fillus

    2014-01-01

    Plasma cell cheilitis is an extremely rare disease, characterized by erythematous-violaceous, ulcerated and asymptomatic plaques, which evolve slowly. The histological characteristics include dermal infiltrate composed of mature plasmocytes. We report a case of Plasma cell angular cheilitis in a 58-year-old male, localized in the lateral oral commissure.

  8. High Resolution 3D Earth Observation Data Analysis for Safeguards Activities

    OpenAIRE

    d'Angelo, Pablo; Rossi, Cristian; Minet, Christian; Eineder, Michael; Flory, Michael; Niemeyer, Irmgard

    2014-01-01

    This paper provides an overview of the investigations performed at DLR with respect to the application of high resolution SAR and optical data for 3D analysis in the context of Safeguards. The Research Center Jülich and the adjacent open cut mines were used as main test sites, and a comprehensive stack of ascending and descending TerraSAR data was acquired over two years. TerraSAR data acquisition was performed, and various ways to visualize and analyze stacks of radar images w...

  9. Quantification of Deltaic Coastal Zone Change Based on Multi-Temporal High Resolution Earth Observation Techniques

    Directory of Open Access Journals (Sweden)

    Emmanuel Vassilakis

    2014-01-01

    Full Text Available A series of methodologies are described in this paper aiming to quantify the natural hazard due to the coastal changes at a deltaic fan. The coastline of Istiaia (North Evia, Greece has been chosen for this study as several areas of accretion and erosion have been identified during the past few decades. We combined different types of datasets, extracted from high resolution panchromatic aerial photographs and traced the contemporary shoreline by high accuracy surveying with Real Time Kinematics (RTK GPS equipment. The interpretation of all shorelines required geo-statistical analysis in a Geographical Information System. A large number of high resolution morphological sections were constructed normally to the coast, revealing erosional and depositional parts of the beach. Retreating and extension rates were calculated for each section reaching the values of 0.98 m/yr and 1.36 m/yr, respectively. The results proved to be very accurate, allowing us to expand the developed methodology by using more complete time-series of remote sensing datasets along with more frequent RTK-GPS surveying.

  10. LENS MODELS OF HERSCHEL-SELECTED GALAXIES FROM HIGH-RESOLUTION NEAR-IR OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Calanog, J. A.; Cooray, A.; Ma, B.; Casey, C. M. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Fu, Hai [Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 (United States); Wardlow, J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Amber, S. [Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA (United Kingdom); Baker, A. J. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Baes, M. [1 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281, B-9000 Gent (Belgium); Bock, J. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Bourne, N.; Dye, S. [School of Physics and Astronomy, University of Nottingham, NG7 2RD (United Kingdom); Bussmann, R. S. [Department of Astronomy, Space Science Building, Cornell University, Ithaca, NY 14853-6801 (United States); Chapman, S. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Dannerbauer, H. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); De Zotti, G. [INAF-Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Dunne, L.; Eales, S. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); and others

    2014-12-20

    We present Keck-Adaptive Optics and Hubble Space Telescope high resolution near-infrared (IR) imaging for 500 μm bright candidate lensing systems identified by the Herschel Multi-tiered Extragalactic Survey and Herschel Astrophysical Terahertz Large Area Survey. Out of 87 candidates with near-IR imaging, 15 (∼17%) display clear near-IR lensing morphologies. We present near-IR lens models to reconstruct and recover basic rest-frame optical morphological properties of the background galaxies from 12 new systems. Sources with the largest near-IR magnification factors also tend to be the most compact, consistent with the size bias predicted from simulations and previous lensing models for submillimeter galaxies (SMGs). For four new sources that also have high-resolution submillimeter maps, we test for differential lensing between the stellar and dust components and find that the 880 μm magnification factor (μ{sub 880}) is ∼1.5 times higher than the near-IR magnification factor (μ{sub NIR}), on average. We also find that the stellar emission is ∼2 times more extended in size than dust. The rest-frame optical properties of our sample of Herschel-selected lensed SMGs are consistent with those of unlensed SMGs, which suggests that the two populations are similar.

  11. Lens Models of Herschel-Selected Galaxies From High-Resolution Near-IR Observations

    CERN Document Server

    Calanog, J A; Cooray, A; Wardlow, J; Ma, B; Amber, S; Baes, M; Bock, J; Bourne, N; Bussmann, R S; Casey, C M; Chapman, S C; Clements, D L; Conley, A; Dannerbauer, H; DeZotti, G; Dunne, L; Dye, S; Eales, S; Farrah, D; Furlanetto, C; Harris, A I; Ivison, R J; Maddox, S J; Magdis, G; Michalowski, M J; Negrello, M; Nightingale, J; O'Bryan, J M; Oliver, S J; Riechers, D; Scott, D; Serjeant, S; Simpson, J; Smith, M; Timmons, N; Thacker, C; Valiante, E; Vieira, J D

    2014-01-01

    We present Keck-Adaptive Optics and Hubble Space Telescope high resolution near-infrared (IR) imaging for 500 um-bright candidate lensing systems identified by the Herschel Multi-tiered Extra-galactic Survey (HerMES) and Herschel Astrophysical Terahertz Survey (H-ATLAS). Out of 87 candidates with near-IR imaging, 15 (~17%) display clear near-IR lensing morphologies. We present near-IR lens models to reconstruct and recover basic rest-frame optical morphological properties of the background galaxies from 12 new systems. Sources with the largest near-IR magnification factors also tend to be the most compact, consistent with the size bias predicted from simulations and pre- vious lensing models for sub-millimeter galaxies. For four new sources that also have high-resolution sub-mm maps, we test for differential lensing between the stellar and dust components and find that the 880 um magnification factor (u_880) is ~1.5 times higher than the near-IR magnification factor (u_NIR), on average. We also find that the ...

  12. Atomic-Resolution Observations of Semi-Crystalline IntegranularThin Films in Silicon Nitride

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, Alexander; Idrobo, Juan C.; Cinibulk, Michael K.; Kisielowski, Christian; Browning, Nigel D.; Ritchie, Robert O.

    2005-08-01

    The thin intergranular phase in a silicon nitride (Si3N4)ceramic, which has been regarded for decades as having an entirely amorphous morphology, is shown to have a semi-crystalline structure. Using two different but complementary high-resolution electron microscopy methods, the intergranular atomic structure was directly imaged at the atomic level. These high-resolution images show that the atomic arrangement of the dopand element cerium takes very periodic positions not only along the interface between the intergranular phase and the Si3N4 matrix grains, but it arranges in a semi-crystalline structure that spans the entire width of the intergranular phase between two adjacent matrix grains, in principle connecting the two separate matrix grains. The result will have implications on the approach of understanding the materials properties of ceramics, most significantly on the mechanical properties and the associated computational modeling of the atomic structure of the thin intergranular phase in Si3N4 ceramics.

  13. Moderate Resolution Spitzer Infrared Spectrograph (IRS) Observations of M, L, and T Dwarfs

    CERN Document Server

    Mainzer, A K; Saumon, D; Marley, M S; Cushing, M C; Sloan, G C; Kirkpatrick, J D; Leggett, S K; Wilson, J C; Roellig, Thomas L.; Marley, Mark S.; Cushing, Michael C.; Wilson, John C.

    2007-01-01

    We present 10 - 19 um moderate resolution spectra of ten M dwarfs, one L dwarf, and two T dwarf systems obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. The IRS allows us to examine molecular spectroscopic features/lines at moderate spectral resolution in a heretofore untapped wavelength regime. These R~600 spectra allow for a more detailed examination of clouds, non-equilibrium chemistry, as well as the molecular features of H2O, NH3, and other trace molecular species that are the hallmarks of these objects. A cloud-free model best fits our mid-infrared spectrum of the T1 dwarf epsilon Indi Ba, and we find that the NH3 feature in epsilon Indi Bb is best explained by a non-equilibrium abundance due to vertical transport in its atmosphere. We examined a set of objects (mostly M dwarfs) in multiple systems to look for evidence of emission features, which might indicate an atmospheric temperature inversion, as well as trace molecular species; however, we found no evidence of eit...

  14. The internal solar angular velocity: Theory, observations and relationship to solar magnetic fields; Proceedings of the Eighth Summer Symposium, Sunspot, NM, Aug. 11-14, 1986

    Science.gov (United States)

    Durney, Bernard R.; Sofia, Sabatino

    The conference presents papers on observations of solar p-mode rotational splittings, observations of surface velocity fields, the equatorial rotation rate in the solar convective zone, chromospheric activity in open clusters, and solar rotation variations from sunspot group statistics. Other topics include adiabatic nonradial oscillations of a differentially rotating star, a spherical harmonic decomposition technique for analyzing steady photospheric flows, turbulent transport in the radiative zone of a rotating star, and the generation of magnetic fields in the sun. Consideration is also given to magnetic fields and the rotation of the solar convection zone, the hydrostatic adjustment time of the solar subconvective layer, models for a differentially rotating solar-convection zone, and horizontal Reynolds stress and the radial rotation law of the sun.

  15. Physical characteristics of faint meteors by light curve and high-resolution observations, and the implications for parent bodies

    Science.gov (United States)

    Subasinghe, Dilini; Campbell-Brown, Margaret D.; Stokan, Edward

    2016-04-01

    Optical observations of faint meteors (10-7 single body objects) show mostly symmetric light curves, surprisingly, and this indicates that light-curve shape is not an indication of fragility or fragmentation behaviour. Approximately 90 per cent of meteors observed with high-resolution video cameras show some form of fragmentation. Our results also show, unexpectedly, that meteors which show negligible fragmentation are more often on high-inclination orbits (i > 60°) than low-inclination ones. We also find that dynamically asteroidal meteors fragment as often as dynamically cometary meteors, which may suggest mixing in the early Solar system, or contamination between the dynamic groups.

  16. High resolution 12CO(2-1) observations of the molecular gas in Centaurus A

    NARCIS (Netherlands)

    Rydbeck, G.; Wiklind, T.; Cameron, M.; Wild, W.; Eckart, A.; Genzel, R.; Rothermel, H.

    1993-01-01

    Observations of (C-12)O(2-1) emission in the dust lane of Centaurus A show that, except for the center region, the overall distribution and kinematics of the molecular gas is consistent with that of ionized gas. Deconvolution of the observed emission reveals (i) a structure agreeing with what would

  17. High spatial resolution IR observations of young stellar objects - A possible disk surrounding HL Tauri

    Science.gov (United States)

    Grasdalen, G. L.; Strom, S. E.; Strom, K. M.; Capps, R. W.; Thompson, D.; Castelaz, M.

    1984-01-01

    High spatial resolution images of the T Tauri star HL Tau were obtained at 1.6 microns and 2.2 microns. The original images as well as maximum entropy image reconstructions reveal a circumstellar envelope structure, similar at both wavelenghts, and extended along P.A. = 112 deg; the 10 percent width of the structure is 1.9 sec (300 AU at 160 pc). The extended structure is interpreted as light scattered toward earth by dust in a disk surrounding this young stellar object. Polarization measurements made at 2.2 microns support this hypothesis. The total solid particle mass is, at minimum, 5 x 10 to the -7th solar mass.

  18. Observations of movement dynamics of flying insects using high resolution lidar

    DEFF Research Database (Denmark)

    Kirkeby, Carsten Thure; Wellenreuther, Maren; Brydegaard, Mikkel

    2016-01-01

    could distinguish three insect clusters based on morphology and found that two contained insects predominantly recorded above the field in the evening, whereas the third was formed by insects near the forest at around 21:30. Together our results demonstrate the capability of lidar for distinguishing......Insects are fundamental to ecosystem functioning and biodiversity, yet the study of insect movement, dispersal and activity patterns remains a challenge. Here we present results from a novel high resolution laser-radar (lidar) system for quantifying flying insect abundance recorded during one...... summer night in Sweden. We compare lidar recordings with data from a light trap deployed alongside the lidar. A total of 22808 insect were recorded, and the relative temporal quantities measured matched the quantities recorded with the light trap within a radius of 5 m. Lidar records showed that small...

  19. LAMOST observations in the Kepler field. Database of low-resolution spectra

    CERN Document Server

    De Cat, P; Ren, A B; Yang, X H; Shi, J R; Luo, A L; Yang, M; Wang, J L; Zhang, H T; Shi, H M; Zhang, W; Dong, Subo; Catanzaro, G; Corbally, C J; Frasca, A; Gray, R O; Molenda-Zakowicz, J; Uytterhoeven, K; Briquet, M; Bruntt, H; Frandsen, S; Kiss, L; Kurtz, D W; Marconi, M; Niemczura, E; Oestensen, R H; Ripepi, V; Smalley, B; Southworth, J; Szabo, R; Telting, J H; Karoff, C; Aguirre, V Silva; Wu, Y; Hou, Y H; Jin, G; Zhou, X L

    2015-01-01

    The nearly continuous light curves with micromagnitude precision provided by the space mission Kepler are revolutionising our view of pulsating stars. They have revealed a vast sea of low-amplitude pulsation modes that were undetectable from Earth. The long time base of Kepler light curves allows an accurate determination of frequencies and amplitudes of pulsation modes needed for in-depth asteroseismic modeling. However, for an asteroseismic study to be successful, the first estimates of stellar parameters need to be known and they can not be derived from the Kepler photometry itself. The Kepler Input Catalog (KIC) provides values for the effective temperature, the surface gravity and the metallicity, but not always with a sufficient accuracy. Moreover, information on the chemical composition and rotation rate is lacking. We are collecting low-resolution spectra for objects in the Kepler field of view with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, Xinglong observatory, China). Al...

  20. Angular spectrum detection instrument for label-free photonic crystal sensors.

    Science.gov (United States)

    Liu, Longju; Xu, Zhen; Dong, Liang; Lu, Meng

    2014-05-01

    An angular spectrum analysis system was demonstrated to monitor the optical resonant mode of a photonic crystal (PC) sensor comprised of a one-dimensional grating structure. Exposed to solutions with different refractive indices or adsorbed with biomaterials, the PC sensor exhibited changes of the optical resonant modes. The developed detection system utilized a focused laser beam to detect shifts of the resonant angle, and thereby allowed a kinetic analysis of chemical absorption. Such a detection apparatus offers an adjustable angular resolution and a tunable detection range for a wide variety of refractometric sensing applications. A limit of detection of 6.57×10(-5) refractive index unit has been observed. The instrument also offers an imaging capability of rapidly characterizing low-contrast samples deposited on the PC surface with a spatial resolution of 10 μm.

  1. Combining angular response classification and backscatter imagery segmentation for benthic biological habitat mapping

    Science.gov (United States)

    Che Hasan, Rozaimi; Ierodiaconou, Daniel; Laurenson, Laurie

    2012-01-01

    Backscatter information from multibeam echosounders (MBES) have been shown to contain useful information for the characterisation of benthic habitats. Compared to backscatter imagery, angular response of backscatter has shown advantages for feature discrimination. However its low spatial resolution inhibits the generation of fine scale habitat maps. In this study, angular backscatter response was combined with image segmentation of backscatter imagery to characterise benthic biological habitats in Discovery Bay Marine National Park, Victoria, Australia. Angular response of backscatter data from a Reson Seabat 8101 MBES (240 kHz) was integrated with georeferenced underwater video observations for constructing training data. To produce benthic habitat maps, decision tree supervised classification results were combined with mean shift image segmentation for class assignment. The results from mean angular response characteristics show effects of incidence angle at the outer angle for invertebrates (INV) and mixed red and invertebrates (MRI) classes, whilst mixed brown algae (MB) and mixed brown algae and invertebrates (MBI) showed similar responses independent from incidence angle. Automatic segmentation processing produce over segmented results but showed good discrimination between heterogeneous regions. Accuracy assessment from habitat maps produced overall accuracies of 79.6% (Kappa coefficient = 0.66) and 80.2% (Kappa coefficient = 0.67) for biota and substratum classifications respectively. MRI and MBI produced the lowest average accuracy while INV the highest. The ability to combine angular response and backscatter imagery provides an alternative approach for investigating biological information from acoustic backscatter data.

  2. Complex mean circulation over the inner shelf south of Martha's Vineyard revealed by observations and a high-resolution model

    Science.gov (United States)

    Ganju, Neil K.; Lentz, Steven J.; Kirincich, Anthony R.; Farrar, J. Thomas

    2011-01-01

    Inner-shelf circulation is governed by the interaction between tides, baroclinic forcing, winds, waves, and frictional losses; the mean circulation ultimately governs exchange between the coast and ocean. In some cases, oscillatory tidal currents interact with bathymetric features to generate a tidally rectified flow. Recent observational and modeling efforts in an overlapping domain centered on the Martha's Vineyard Coastal Observatory (MVCO) provided an opportunity to investigate the spatial and temporal complexity of circulation on the inner shelf. ADCP and surface radar observations revealed a mean circulation pattern that was highly variable in the alongshore and cross-shore directions. Nested modeling incrementally improved representation of the mean circulation as grid resolution increased and indicated tidal rectification as the generation mechanism of a counter-clockwise gyre near the MVCO. The loss of model skill with decreasing resolution is attributed to insufficient representation of the bathymetric gradients (Δh/h), which is important for representing nonlinear interactions between currents and bathymetry. The modeled momentum balance was characterized by large spatial variability of the pressure gradient and horizontal advection terms over short distances, suggesting that observed inner-shelf momentum balances may be confounded. Given the available observational and modeling data, this work defines the spatially variable mean circulation and its formation mechanism—tidal rectification—and illustrates the importance of model resolution for resolving circulation and constituent exchange near the coast. The results of this study have implications for future observational and modeling studies near the MVCO and other inner-shelf locations with alongshore bathymetric variability.

  3. Observation of off-Hugoniot shocked states with ultrafast time resolution

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, M; Crowhurst, J; Bastea, S; Zaug, J

    2010-02-23

    We apply ultrafast single shot interferometry to determine the pressure and density of argon shocked from up to 7.8 GPa static initial pressure in a diamond anvil cell. This method enables the observation of thermodynamic states distinct from those observed in either single shock or isothermal compression experiments, and the observation of ultrafast dynamics in shocked materials. We also present a straightforward method for interpreting ultrafast shock wave data which determines the index of refraction at the shock front, and the particle and shock velocities for shock waves in transparent materials. Based on these methods, we observe shocked thermodynamic states between the room temperature isotherm of argon and the shock adiabat of cryogenic argon at final shock pressures up to 28 GPa.

  4. Smoke Dispersion Modeling Over Complex Terrain Using High-Resolution Meteorological Data and Satellite Observations: The FireHub Platform

    Science.gov (United States)

    Solomos, S.; Amiridis, V.; Zanis, P.; Gerasopoulos, E.; Sofiou, F. I.; Herekakis, T.; Brioude, J.; Stohl, A.; Kahn, R. A.; Kontoes, C.

    2015-01-01

    A total number of 20,212 fire hot spots were recorded by the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument over Greece during the period 2002e2013. The Fire Radiative Power (FRP) of these events ranged from 10 up to 6000 MW at 1 km resolution, and many of these fire episodes resulted in long-range transport of smoke over distances up to several hundred kilometers. Three different smoke episodes over Greece are analyzed here using real time hot-spot observations from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) satellite instrument as well as from MODIS hot-spots. Simulations of smoke dispersion are performed with the FLEXPART-WRF model and particulate matter emissions are calculated directly from the observed FRP. The modeled smoke plumes are compared with smoke stereo-heights from the Multiangle Imaging Spectroradiometer (MISR) instrument and the sensitivities to atmospheric and modeling parameters are examined. Driving the simulations with high resolution meteorology (4 4 km) and using geostationary satellite data to identify the hot spots allows the description of local scale features that govern smoke dispersion. The long-range transport of smoke is found to be favored over the complex coastline environment of Greece due to the abrupt changes between land and marine planetary boundary layers (PBL) and the decoupling of smoke layers from the surface.

  5. Smoke dispersion modeling over complex terrain using high resolution meteorological data and satellite observations - The FireHub platform

    Science.gov (United States)

    Solomos, S.; Amiridis, V.; Zanis, P.; Gerasopoulos, E.; Sofiou, F. I.; Herekakis, T.; Brioude, J.; Stohl, A.; Kahn, R. A.; Kontoes, C.

    2015-10-01

    A total number of 20,212 fire hot spots were recorded by the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument over Greece during the period 2002-2013. The Fire Radiative Power (FRP) of these events ranged from 10 up to 6000 MW at 1 km resolution, and many of these fire episodes resulted in long-range transport of smoke over distances up to several hundred kilometers. Three different smoke episodes over Greece are analyzed here using real time hot-spot observations from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) satellite instrument as well as from MODIS hot-spots. Simulations of smoke dispersion are performed with the FLEXPART-WRF model and particulate matter emissions are calculated directly from the observed FRP. The modeled smoke plumes are compared with smoke stereo-heights from the Multiangle Imaging Spectroradiometer (MISR) instrument and the sensitivities to atmospheric and modeling parameters are examined. Driving the simulations with high resolution meteorology (4 × 4 km) and using geostationary satellite data to identify the hot spots allows the description of local scale features that govern smoke dispersion. The long-range transport of smoke is found to be favored over the complex coastline environment of Greece due to the abrupt changes between land and marine planetary boundary layers (PBL) and the decoupling of smoke layers from the surface.

  6. ALMA high spatial resolution observations of the dense molecular region of NGC 6302

    Science.gov (United States)

    Santander-García, M.; Bujarrabal, V.; Alcolea, J.; Castro-Carrizo, A.; Sánchez Contreras, C.; Quintana-Lacaci, G.; Corradi, R. L. M.; Neri, R.

    2017-01-01

    Context. The mechanism behind the shaping of bipolar planetary nebulae is still poorly understood. It is becoming increasingly clear that the main agents must operate at their innermost regions, where a significant equatorial density enhancement should be present and related to the collimation of light and jet launching from the central star preferentially towards the polar directions. Most of the material in this equatorial condensation must be lost during the asymptotic giant branch as stellar wind and later released from the surface of dust grains to the gas phase in molecular form. Accurately tracing the molecule-rich regions of these objects can give valuable insight into the ejection mechanisms themselves. Aims: We investigate the physical conditions, structure and velocity field of the dense molecular region of the planetary nebula NGC 6302 by means of ALMA band 7 interferometric maps. Methods: The high spatial resolution of the 12CO and 13CO J = 3-2 ALMA data allows for an analysis of the geometry of the ejecta in unprecedented detail. We built a spatio-kinematical model of the molecular region with the software SHAPE and performed detailed non-LTE calculations of excitation and radiative transfer with the shapemol plug-in. Results: We find that the molecular region consists of a massive ring out of which a system of fragments of lobe walls emerge and enclose the base of the lobes visible in the optical. The general properties of this region are in agreement with previous works, although the much greater spatial resolution of the data allows for a very detailed description. We confirm that the mass of the molecular region is 0.1 M⊙. Additionally, we report a previously undetected component at the nebular equator, an inner, younger ring inclined 60° with respect to the main ring, showing a characteristic radius of 7.5 × 1016 cm, a mass of 2.7 × 10-3M⊙, and a counterpart in optical images of the nebula. This inner ring has the same kinematical age as

  7. Seismic diagnostics for transport of angular momentum in stars 2. Interpreting observed rotational splittings of slowly-rotating red giant stars

    CERN Document Server

    Goupil, M J; Marques, J P; Ouazzani, R M; Belkacem, K; Lebreton, Y; Samadi, R

    2012-01-01

    Asteroseismology with the space-borne missions CoRoT and Kepler provides a powerful mean of testing the modeling of transport processes in stars. Rotational splittings are currently measured for a large number of red giant stars and can provide stringent constraints on the rotation profiles. The aim of this paper is to obtain a theoretical framework for understanding the properties of the observed rotational splittings of red giant stars with slowly rotating cores. This allows us to establish appropriate seismic diagnostics for rotation of these evolved stars. Rotational splittings for stochastically excited dipolar modes are computed adopting a first-order perturbative approach for two $1.3 M_\\odot$ benchmark models assuming slowly rotating cores. For red giant stars with slowly rotating cores, we show that the variation of the rotational splittings of $\\ell=1$ modes with frequency depends only on the large frequency separation, the g-mode period spacing, and the ratio of the average envelope to core rotatio...

  8. Tracing the Angular Dependence of the CGM

    Science.gov (United States)

    Nattinger, Michael; Christensen, Charlotte

    2017-01-01

    The circumgalactic media (CGM) is enriched with metals through a process called the baryon cycle, which may play a significant role in the regulation of star formation. While the relationship between the CGM’s baryonic makeup and impact parameter is well documented, the relationship between the baryonic distribution of the CGM and the azimuthal angle out of the plane of the galaxy remains an open question. We investigated the angular distribution of baryons in the CGM by creating mock-absorption line spectra for a high-resolution simulation of a Milky Way-like galaxy at redshift zero. By comparison with data from the Cosmic Origins Spectrograph-Halos survey, we determined that our equivalent widths of HI, MgII, CIII, SiII, and SiIII are consistent with observations. Using our data, we found that low ionization state material is more prevalent at low azimuthal angles and that high ionization state material is more prevalent at high angles within the virial radius. We attributed this increased ionization to higher temperatures at high angles. We also found that the highest metallicity levels appear at high and low azimuthal angles, with lower metallicities at middle angles. This evidence supports the recycled accretion model of CGM baryon flow.

  9. Angular cheilitis after tonsillectomy.

    Science.gov (United States)

    England, R J; Lau, M; Ell, S R

    1999-08-01

    The operation of tonsillectomy requires the oral cavity to be held open mechanically in an unconscious patient, and intra-oral instrumentation to occur. Angular cheilitis may arise as a result of this after operation. This can cause morbidity and delay the re-establishment of a normal diet. The aim of this study was to identify what factors increase the likelihood of developing this problem postoperatively. Sixty patients were randomly selected in a prospective manner. Preoperative, intraoperative and postoperative variables were recorded. The frequency of development of postoperative angular cheilitis was recorded. The prevalence of the condition was related to the prerecorded variables. Parametric analysis showed that the chance of developing angular cheilitis was directly related to the use of diathermy haemostasis (P = 0.05). Logistic regression analysis showed that the odds ratio of developing this complication if diathermy was used is 3.5 (95% confidence intervals 0.99, 12.4) and operation difficulty may also be a relevant variable. No other recorded variables were found to be significant.

  10. The study of brain activity during the observation of commercial advertising by using high resolution EEG techniques.

    Science.gov (United States)

    Vecchiato, Giovanni; Astolfi, Laura; De Vico Fallani, Fabrizio; Salinari, Serenella; Cincotti, Febo; Aloise, Fabio; Mattia, Donatella; Marciani, Maria Grazia; Bianchi, Luigi; Soranzo, Ramon; Babiloni, Fabio

    2009-01-01

    In this paper we illustrate the capability of tracking brain activity during the observation of commercial TV spots by using advanced high resolution EEG statistical techniques in time and frequency domains. In particular, we analyzed the statistically significant cortical spectral power activity in different frequency bands during the observation of a commercial video clip related to the use of a beer in a group of 13 normal subjects. In addition, a TV speech of the prime minister of Italy was analyzed in two groups of swing and "supporter" voters. Results suggested that the cortical activity during the observation of commercial spots could vary consistently across the spot. This fact suggest the possibility to remove the part of the spot that are not particularly attractive by using those cerebral indexes. The cortical activity during the observation of the political speech indicated a major cortical activity in the supporters group when compared to the swing voters. In this case, it is possible to conclude that the communication proposed has failed to raise attention or interest on swing voters. In conclusions, high resolution EEG have been proved able to generate useful insights about the particular fruition of TV messages, related to both commercial as well as political fields.

  11. The nature of extragalactic radio-jets from high-resolution radio-interferometric observations

    CERN Document Server

    Perucho, Manel

    2015-01-01

    Extragalactic jets are a common feature of radio-loud active galaxies. The nature of the observed jets in relation to the bulk flow is still unclear. In particular it is not clear whether the observations of parsec-scale jets using the very long baseline interferometric technique (VLBI) reveal wave-like structures that develop and propagate along the jet, or trace the jet flow itself. In this contribution I review the evidence collected during the last years showing that the ridge-lines of helical radio-jets do not correspond to observational artifacts. This conclusion was reached by studying a number of VLBI observations of the radio jet in the quasar S5~0836+710 at different frequencies and epochs. The ridge-line of the emission in the jet coincides at all frequencies within the errors. Moreover, small differences between the ridge-lines as observed at different epochs reveal wave-like motion transversal to the jet propagation axis. I also discuss similar results, albeit with different interpretations, obta...

  12. Quantum Heuristics of Angular Momentum

    Science.gov (United States)

    Levy-Leblond, Jean-Marc

    1976-01-01

    Discusses the quantization of angular momentum components, Heisenberg-type inequalities for their spectral dispersions, and the quantization of the angular momentum modulus, without using operators or commutation relations. (MLH)

  13. Active region fine structure observed at 0.08 arcsec resolution

    CERN Document Server

    Schlichenmaier, R; Hoch, S; Soltau, D; Berkefeld, T; Schmidt, D; Schmidt, W; Denker, C; Balthasar, H; Hofmann, A; Strassmeier, K G; Staude, J; Feller, A; Lagg, A; Solanki, S K; Collados, M; Sigwarth, M; Volkmer, R; Waldmann, T; Kneer, F; Nicklas, H; Sobotka, M

    2016-01-01

    The various mechanisms of magneto-convective energy transport determines the structure of sunspots and active regions. We characterise the appearance of light bridges and other fine structure details and elaborate on their magneto-convective nature. We present speckle-reconstructed images taken with the broad band imager at the 1.5 m GREGOR telescope in the 486nm and 589nm bands. We estimate the spatial resolution from the noise characteristics of the image bursts and obtain 0.08" at 589nm. We describe structure details in individual best images as well as the temporal evolution of selected features. We find branched dark lanes extending along thin (~1") light bridges in sunspots at various heliocentric angles. In thick (~2") light bridges the branches are disconnected from the central lane and have a `Y' shape with a bright grain toward the umbra. The images reveal that light bridges exist on varying intensity levels and that their small-scale features evolve on time scales of minutes. Faint light bridges sh...

  14. Ozone Profile Retrieval from Satellite Observation Using High Spectral Resolution Infrared Sounding Instrument

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper presents a preliminary result on the retrieval of atmospheric ozone profiles using an im proved regression technique and utilizing the data from the Atmospheric InfraRed Sounder (AIRS), a hyper-spectral instrument expected to be flown on the EOS-AQUA platform in 2002. Simulated AIRS spectra were used to study the sensitivity of AIRS radiance on the tropospheric and stratospheric ozone changes, and to study the impact of various channel combinations on the ozone profile retrieval. Sensitivity study results indicate that the AIRS high resolution spectral channels between the wavenumber 650- 800 cm-1 provide very useful information to accurately retrieve tropospheric and stratospheric ozone pro files. Eigenvector decomposition of AIRS spectra indicate that no more than 100 eigenvectors are needed to retrieve very accurate ozone profiles. The accuracy of the retrieved atmospheric ozone profile from the pres ent technique and utilizing the AIRS data was compared with the accuracy obtained from current Advanced TIROS Operational Vertical Sounder (ATOVS) data aboard National Oceanic and Atmospheric Admini stration (NOAA) satellites. As expected, a comparison of retrieval results confirms that the ozone profile re trieved with the AIRS data is superior to that of ATOVS.

  15. Chromospheric activity on late-type star DM UMa using high-resolution spectroscopic observations

    CERN Document Server

    Zhang, LiYun; Han, Xianming L; Chang, Liang; Wang, Daimei

    2016-01-01

    We present new 14 high-resolution echelle spectra to discuss the level of chromospheric activity of DM UMa in {He I} D3, {Na I} D1, D2, Halpha, and {Ca II} infrared triplet lines (IRT). It is the first time to discover the emissions above the continuum in the {He I} D3 lines on 2015 February 9 and 10. The emission on February 9 is the strongest one ever detected for DM UMa. We analysed these chromospheric active indicators by employing the spectral subtraction technique. The subtracted spectra reveal weak emissions in the {Na I} D1, D2 lines, strong emission in the Halpha line, and clear excess emissions in the {Ca II} IRT lines. Our values for the EW8542/EW8498 ratio are on the low side, in the range of 1.0-1.7. There are also clear phase variations of the level of chromospheric activity in equivalent width (EW) light curves in these chromospheric active lines (especially the Halpha line). These phenomena might be explained by flare events or rotational modulations of the level of chromospheric activity.

  16. NGC 4102: High Resolution Infrared Observations of a Nuclear Starburst Ring

    CERN Document Server

    Beck, Sara C; Turner, Jean L

    2010-01-01

    The composite galaxy NGC 4102 hosts a LINER nucleus and a starburst. We mapped NGC 4102 in the 12.8 micron line of [NeII], using the echelon spectrometer TEXES on the NASA IRTF, to obtain a data cube with 1.5" spatial and 25 km/s spectral, resolution. Combining near-infrared, radio, and the [NeII] data shows that the extinction to the starburst is substantial, more than 2 magnitudes at K band, and that the neon abundance is less than half solar. We find that the star formation in the nuclear region is confined to a rotating ring or disk of 4.3" (~300 pc) diameter, inside the Inner Lindblad Resonance. This region is an intense concentration of mass, with a dynamical mass of ~3 x 10^9 solar masses, and of star formation. The young stars in the ring produce the [NeII] flux reported by Spitzer for the entire galaxy. The mysterious blue component of line emission detected in the near-infrared is also seen in [NeII]; it is not a normal AGN outflow.

  17. Observations of movement dynamics of flying insects using high resolution lidar.

    Science.gov (United States)

    Kirkeby, Carsten; Wellenreuther, Maren; Brydegaard, Mikkel

    2016-07-04

    Insects are fundamental to ecosystem functioning and biodiversity, yet the study of insect movement, dispersal and activity patterns remains a challenge. Here we present results from a novel high resolution laser-radar (lidar) system for quantifying flying insect abundance recorded during one summer night in Sweden. We compare lidar recordings with data from a light trap deployed alongside the lidar. A total of 22808 insect were recorded, and the relative temporal quantities measured matched the quantities recorded with the light trap within a radius of 5 m. Lidar records showed that small insects (wing size 2.5 mm(2) in cross-section) were most abundant near the lidar beam before 22:00 and then moved towards the light trap between 22:00 and 23:30. We could distinguish three insect clusters based on morphology and found that two contained insects predominantly recorded above the field in the evening, whereas the third was formed by insects near the forest at around 21:30. Together our results demonstrate the capability of lidar for distinguishing different types of insect during flight and quantifying their movements.

  18. Observations of movement dynamics of flying insects using high resolution lidar

    Science.gov (United States)

    Kirkeby, Carsten; Wellenreuther, Maren; Brydegaard, Mikkel

    2016-07-01

    Insects are fundamental to ecosystem functioning and biodiversity, yet the study of insect movement, dispersal and activity patterns remains a challenge. Here we present results from a novel high resolution laser-radar (lidar) system for quantifying flying insect abundance recorded during one summer night in Sweden. We compare lidar recordings with data from a light trap deployed alongside the lidar. A total of 22808 insect were recorded, and the relative temporal quantities measured matched the quantities recorded with the light trap within a radius of 5 m. Lidar records showed that small insects (wing size insects (wing size >2.5 mm2 in cross-section) were most abundant near the lidar beam before 22:00 and then moved towards the light trap between 22:00 and 23:30. We could distinguish three insect clusters based on morphology and found that two contained insects predominantly recorded above the field in the evening, whereas the third was formed by insects near the forest at around 21:30. Together our results demonstrate the capability of lidar for distinguishing different types of insect during flight and quantifying their movements.

  19. SPAM: A data reduction recipe for high-resolution, low-frequency radio-interferometric observations

    CERN Document Server

    Intema, H T

    2014-01-01

    High-resolution astronomical imaging at sub-GHz radio frequencies has been available for more than 15 years, with the VLA at 74 and 330 MHz, and the GMRT at 150, 240, 330 and 610 MHz. Recent developments include wide-bandwidth upgrades for VLA and GMRT, and commissioning of the aperture-array-based, multi-beam telescope LOFAR. A common feature of these telescopes is the necessity to deconvolve the very many detectable sources within their wide fields-of-view and beyond. This is complicated by gain variations in the radio signal path that depend on viewing direction. One such example is phase errors due to the ionosphere. Here I discuss the inner workings of SPAM, a set of AIPS-based data reduction scripts in Python that includes direction-dependent calibration and imaging. Since its first version in 2008, SPAM has been applied to many GMRT data sets at various frequencies. Many valuable lessons were learned, and translated into various SPAM software modifications. Nowadays, semi-automated SPAM data reduction ...

  20. ALMA high spatial resolution observations of the dense molecular region of NGC 6302

    CERN Document Server

    Santander-García, M; Alcolea, J; Castro-Carrizo, A; Sánchez-Contreras, C; Quintana-Lacaci, G; Corradi, R L M; Neri, R

    2016-01-01

    The mechanism behind the shaping of bipolar planetary nebulae is still poorly understood. Accurately tracing the molecule-rich equatorial regions of post-AGB stars can give valuable insight into the ejection mechanisms at work. We investigate the physical conditions, structure and velocity field of the dense molecular region of the planetary nebula NGC 6302 by means of ALMA band 7 interferometric maps. The high spatial resolution of the $^{12}$CO and $^{13}$CO J=3-2 ALMA data allows for an analysis of the geometry of the ejecta in unprecedented detail. We built a spatio-kinematical model of the molecular region with the software SHAPE and performed detailed non-LTE calculations of excitation and radiative transfer with the SHAPEMOL plug-in. We find that the molecular region consists of a massive ring out of which a system of fragments of lobe walls emerge and enclose the base of the lobes visible in the optical. The general properties of this region are in agreement with previous works, although the much grea...

  1. 应用于四旋翼无人机角速度估计的几何滑模观测器设计%Geometric sliding mode observer design with application to angular velocity estimation of quadrotor UAV

    Institute of Scientific and Technical Information of China (English)

    安宏雷; 李杰; 王剑; 王建文; 马宏绪

    2013-01-01

    Traditional quaternion-based sliding mode observer for angular velocity estimating has to introduce the process of mandatory rescaling which affects the tracking performance of the observer algorithm.In this work,a sliding mode observer design framework is proposed, based on the Lie group method of numerical integration on manifolds for angular velocity estimation of quadrotor attitude.The algorithm constructs sliding mode feedback in the space of equivalent Lie algebra of homogeneous manifolds on the basis of equivariant mapping ideological.It avoids the complexity of constructing sliding mode feedback in homogeneous space directly,and eliminates the process of mandatory rescaling which is required by the traditional methods in each integration step.The simulation results show that the algorithm of geometric sliding mode observer is effective.%对四旋翼无人机的角速度进行估计时,传统的基于单位四元数的滑模观测器需要引入强制比例重调,因而影响了跟踪精度。提出一种基于数值积分的李群方法的滑模观测器设计框架。该算法基于等变映射思想,在齐性流形空间的等价李代数空间中设计滑模反馈,从而避免了直接在流形空间中设计反馈的复杂性,并消除了传统方法在每个积分步骤中强制加入的比例重调,提高了观测器的跟踪性能。仿真结果表明,几何滑模观测器算法可以有效地对四旋翼无人机的角速度进行估计。

  2. Far-infrared observations of W51 with high spatial resolution

    Science.gov (United States)

    Harvey, P. M.; Hoffmann, W. F.; Campbell, M. F.

    1975-01-01

    Observations of the core of W51 have been made from the NASA C-141 Airborne Infrared Observatory at 55 microns with 17-, 35-, and 85-arc sec apertures and at 100 microns with a 35-arc sec aperture. These observations suggest the presence of a small less than about 20 arc sec source at 55 microns surrounded by a much broader diffuse background. In the center of the source the optical depth at 55 and 100 microns is on the order of 0.1-0.2.

  3. High spatial resolution multi-color observations of Neptune during occultation by the moon

    Science.gov (United States)

    Veverka, J.

    1976-01-01

    Preparations for the observation of Mars occultation using the 36 inch telescope on a C-141 airborne observatory were described, including technical improvements made to existing equipment. The abstracts of the following four publications supported by the grant were presented: (1) atmosphere composition from refractivity measurements made during occultations, (2) how big is lapetus?, (3) the diameter of Titan, (4) design and operating characteristics of voltage to frequency converters suited for occultation work. The planned observation of the April 8, 1976 occultation of the epsilon Gem star from the C-141 airborne observatory was described.

  4. High spatial resolution infrared imaging of L1551-IRS 5 - Direct observations of its circumstellar envelope

    Science.gov (United States)

    Moneti, Andrea; Forrest, William J.; Pipher, Judith L.; Woodward, Charles E.

    1988-01-01

    Images of L1551-IRS 5 were obtained at 1.65, 2.2, and 3.8 microns using the University of Rochester's Infrared Array Camera. It is found that IRS 5 is spatially resolved, and that it is elongated: the observed FWHM size of IRS 5 is 4.1 x 2.8 arcsec-squared at 2.2 microns. These observations are interpreted in terms of a flattened circumstellar envelope that is viewed from about 18 deg above its equatorial plane, a configuration that has been treated theoretically by Lefevre et al. In this model the central star is not seen directly, but only light scattered toward the observer from the visible polar region, where the envelope is thinnest, is observed. It is deduced that the envelope has a diameter of 1000 AU, a molecular hydrogen density of greater than or approximately equal to 4 x 10 to the 6th/cu cm, and a mass of greater than or approximately equal to 0.02 M solar mass, which results in an extinction of Av greater than about 33 mag to the central source.

  5. Use of Kendall's coefficient of concordance to assess agreement among observers of very high resolution imagery

    Science.gov (United States)

    Ground-based vegetation monitoring methods are expensive, time-consuming, and limited in sample-size. Aerial imagery is appealing to managers because of the reduced time and expense and the increase in sample size. One challenge of aerial imagery is detecting differences among observers of the sam...

  6. High-Resolution Modeling Disturbance-Induced Forest Carbon Dynamics with Lidar and Landsat Observations

    Science.gov (United States)

    Zhao, M.; Huang, C.; Hurtt, G. C.; Dubayah, R.; Fisk, J.; Sahajpal, R.; Flanagan, S.; Swatantran, A.; Huang, W.; Tang, H.; ONeil-Dunne, J.; Johnson, K. D.

    2015-12-01

    Forest stands are dynamic in a status from severely, partially disturbed, or undisturbed to different stages of recovery towards maturity and equilibrium. Forest ecosystem models generally use potential biomass (an assumption of equilibrium status) as initial biomass, which is unrealistic and could result in unreliable estimates of disturbance-induced carbon changes. To accurately estimate spatiotemporal changes of forest carbon stock and fluxes, it requires accurate information on initial biomass, the extent and severity of disturbance, and following land use. We demonstrate a prototype system to achieve this goal by integrating 1-m small footprint Lidar acquired in year 2004, 30-m Landsat disturbances from 1984 to 2011, and an individual-based structure height Ecosystem Demography (ED) model. Lidar provides critical information on forest canopy height, improving the accuracy of initial forest biomass estimates; impervious surfaces data and yearly disturbance data from Landsat provide information on wall-to-wall yearly natural and anthropogenic disturbances and their severity (on average 0.32% for the natural and 0.19% for the anthropogenic for below test area); ED model plays a central role by linking both Lidar canopy height and Landsat disturbances with ecosystem processes. We tested the system at 90-m spatial resolution in Charles County, Maryland, by running ED model for six experiments, the combinations of three initial biomass (potential, moderate and low initial biomass constrained by Lidar canopy height) with two disturbance scenarios (with and without anthropogenic disturbances). Our experiments show that estimated changes of carbon stock and flux are sensitive to initial biomass status and human-induced land cover change. Our prototype system can assess regional carbon dynamics at local scale under changing climate and disturbance regimes, and provide useful information for forest management and land use policies.

  7. Orbital angular momentum in the nucleons

    CERN Document Server

    Lorcé, Cédric

    2014-01-01

    In the last decade, it has been realized that the orbital angular momentum of partons inside the nucleon plays a major role. It contributes significantly to nucleon properties and is at the origin of many asymmetries observed in spin physics. It is therefore of paramount importance to determine this quantity if we want to understand the nucleon internal structure and experimental observables. This triggered numerous discussions and controversies about the proper definition of orbital angular momentum and its extraction from experimental data. We summarize the present situation and discuss recent developments in this field.

  8. High resolution spectroscopy of methyltrioxorhenium: towards the observation of parity violation in chiral molecules

    CERN Document Server

    Stoeffler, Clara; Shelkovnikov, Alexander; Daussy, Christophe; Amy-Klein, Anne; Chardonnet, Christian; Guy, Laure; Crassous, Jeanne; Huet, Thérèse; Soulard, Pascale; Asselin, Pierre

    2010-01-01

    Originating from the weak interaction, parity violation in chiral molecules has been considered as a possible origin of the biohomochirality. It was predicted in 1974 but has never been observed so far. Parity violation should lead to a very tiny frequency difference in the rovibrational spectra of the enantiomers of a chiral molecule. We have proposed to observe this predicted frequency difference using the two photon Ramsey fringes technique on a supersonic beam. Promising candidates for this experiment are chiral oxorhenium complexes, which present a large effect, can be synthesized in large quantity and enantiopure form, and can be seeded in a molecular beam. As a first step towards our objective, a detailed spectroscopic study of methyltrioxorhenium (MTO) has been undertaken. It is an ideal test molecule as the achiral parent molecule of chiral candidates for the parity violation experiment. For the 187Re MTO isotopologue, a combined analysis of Fourier transform microwave and infrared spectra as well as...

  9. Observational and Theoretical Foundation for the Dynamics in a High-resolution Sea Ice Model

    Science.gov (United States)

    2016-06-07

    The thickness distribution of the ice cover has a significant impact on heat and energy exchange between the atmosphere, ice , and ocean . 2) I am...the ice mechanics at a regional scale, from observations made during the Sea Ice Mechanics Initiative (SIMI) and the Surface Heat Budget of the Arctic ...floes was stronger than the correlation between sites on the same floe. This result also validates our approach to measuring stress in the ice cover

  10. Fast-response high-resolution temperature sonde aimed at contamination-free profile observations

    Directory of Open Access Journals (Sweden)

    K. Shimizu

    2010-08-01

    Full Text Available An innovative temperature sonde, equipped with an ultra thin tungsten wire, has been developed to meet the scientific requirements suitable for climate change research. The response time, shorter than 40 ms achieved at the altitude of 30 km, enables the temperature observations with the radiation correction of less than 0.4 K in the whole observation range. Test flights during the development stage reveal significant artificial perturbations in the observed temperature profiles. They are identified as the thermal contamination arising primarily from radiosonde package box with some additional effect from the launching balloon. The modification of the sensor mount successfully removed the contribution from the former effect. On the other hand, some filtering procedure need to be applied to remove the latter, although the use of a long suspension line will be effective to reduce the noise. There remain unavoidable small fluctuations (less than 0.4 K that are brought about by the solid angle modulation of the illumination against the sensor body in the daytime. While conventional radiation correction may unintentionally have taken a part of such contaminations into account, they may not be properly corrected in existing radiosonde data, as the origin of errors has not been identified. Our tungsten sonde that scarcely relies on the ambiguous correction procedures is ideal for serving as an international reference.

  11. High-resolution observations of SN 2001gd in NGC 5033

    CERN Document Server

    Pérez-Torres, M A; Marcaide, J M; Guerrero, M A; Lundqvist, P; Shapiro, I I; Ros, E; Lara, L; Guirado, J C; Weiler, K W; Stockdale, C J; Perez-Torres, Miguel A.

    2005-01-01

    We report on 8.4 GHz VLBI observations of SN2001gd in the spiral galaxy NGC5033 made on 26 June 2002 and 8 April 2003. Our data nominally suggests a relatively strong deceleration for the expansion of SN2001gd, but we cannot dismiss the possibility of a free supernova expansion. From our VLBI observations on 8 April 2003, we inferred a minimum total energy in relativistic particles and magnetic fields in the supernova shell of E_min =(0.3-14) 10^{47} ergs, and a corresponding equipartition average magnetic field of B_min = (50--350) mG. We also present multiwavelength VLA measurements of SN2001gd, which are well fit by an optically thin, synchrotron spectrum, partially absorbed by thermal plasma. We obtain a supernova flux density of (1.02 +/- 0.05) mJy at the observing frequency of 8.4 GHz for the second epoch, which results in an isotropic radio luminosity of (6.0 +/- 0.3) * 10^{36} ergs between 1.4 and 43.3 GHz, at an adopted distance of 13.1 Mpc. Finally, we report on an XMM-Newton X-ray detection of SN20...

  12. Inflows and Outflows in the Dwarf Starburst Galaxy NGC 5253: High-Resolution HI Observations

    CERN Document Server

    Kobulnicky, Henry A

    2007-01-01

    VLA and Parkes 64 m radiotelescope 21-cm observations of the starburst dwarf galaxy NGC 5253 reveal a multi-component non-axisymmetric HI distribution. The component associated with the stellar body shows evidence for a small amount of rotational support aligned with the major axis, in agreement with optically measured kinematics and consistent with the small galaxian mass. Approximately 20-30% of the HI emission is associated with a second component, an HI "plume" extending along the optical minor axis to the southeast. We consider outflow, inflow, and tidal origins for this feature. Outflow appears improbable, inflow is a possibility, and tidal debris is most consistent with the observations. These observations also reveal a filamentary third component that includes an 800 pc diameter HI shell or bubble to the west of the nucleus, coinciding with an Halpha shell. The mass of HI in the shell may be as large as ~4x10^6 Msun. This large mass, coupled with the lack of expansion signatures in the neutral and ion...

  13. Marine boundary layer cloud property retrievals from high-resolution ASTER observations: case studies and comparison with Terra MODIS

    Science.gov (United States)

    Werner, Frank; Wind, Galina; Zhang, Zhibo; Platnick, Steven; Di Girolamo, Larry; Zhao, Guangyu; Amarasinghe, Nandana; Meyer, Kerry

    2016-12-01

    A research-level retrieval algorithm for cloud optical and microphysical properties is developed for the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard the Terra satellite. It is based on the operational MODIS algorithm. This paper documents the technical details of this algorithm and evaluates the retrievals for selected marine boundary layer cloud scenes through comparisons with the operational MODIS Data Collection 6 (C6) cloud product. The newly developed, ASTER-specific cloud masking algorithm is evaluated through comparison with an independent algorithm reported in [Zhao and Di Girolamo(2006)]. To validate and evaluate the cloud optical thickness (τ) and cloud effective radius (reff) from ASTER, the high-spatial-resolution ASTER observations are first aggregated to the same 1000 m resolution as MODIS. Subsequently, τaA and reff, aA retrieved from the aggregated ASTER radiances are compared with the collocated MODIS retrievals. For overcast pixels, the two data sets agree very well with Pearson's product-moment correlation coefficients of R > 0.970. However, for partially cloudy pixels there are significant differences between reff, aA and the MODIS results which can exceed 10 µm. Moreover, it is shown that the numerous delicate cloud structures in the example marine boundary layer scenes, resolved by the high-resolution ASTER retrievals, are smoothed by the MODIS observations. The overall good agreement between the research-level ASTER results and the operational MODIS C6 products proves the feasibility of MODIS-like retrievals from ASTER reflectance measurements and provides the basis for future studies concerning the scale dependency of satellite observations and three-dimensional radiative effects.

  14. Oxygen lines in solar granulation. I. Testing 3D models against new observations with high spatial and spectral resolution

    CERN Document Server

    Pereira, Tiago M D; Asplund, Martin

    2009-01-01

    Aims: we seek to provide additional tests of the line formation of theoretical 3D solar photosphere models. In particular, we set out to test the spatially-resolved line formation at several viewing angles, from the solar disk-centre to the limb and focusing on atomic oxygen lines. The purpose of these tests is to provide additional information on whether the 3D model is suitable to derive the solar oxygen abundance. We also aim to empirically constrain the NLTE recipes for neutral hydrogen collisions, using the spatially-resolved observations of the OI 777 nm lines. Methods: using the Swedish 1-m Solar Telescope we obtained high-spatial-resolution observations of five atomic oxygen lines (along with lines for other species) for five positions on the solar disk. These observations have a high spatial and spectral resolution, and a continuum intensity contrast up to 9% at 615 nm. The theoretical line profiles were computed using the 3D model, with a full 3D NLTE treatment for oxygen and LTE for the other lines...

  15. A downscaling approach for SMOS land observations: evaluation of high-resolution soil moisture maps over the Iberian Peninsula

    OpenAIRE

    Piles Guillem, Maria; Sanchez, Nilda; Vall-Llossera Ferran, Mercedes Magdalena; Camps Carmona, Adriano José; Martinez Fernandez, Jose; Martinez, Justino; González Gambau, Veronica

    2014-01-01

    The ESA's Soil Moisture and Ocean Salinity (SMOS) mission is the first satellite devoted to measure the Earth's surface soil moisture. It has a spatial resolution of similar to 40 km and a 3-day revisit. In this paper, a downscaling algorithm is presented as a new ability to obtain multiresolution soil moisture estimates from SMOS using visible-to-infrared remotely sensed observations. This algorithm is applied to combine 2 years of SMOS and MODIS Terra/Aqua data over the Iberian Peninsula in...

  16. The SKA as a Doorway to Angular Momentum

    CERN Document Server

    Obreschkow, D; Popping, A; Power, C; Quinn, P; Staveley-Smith, L

    2015-01-01

    Angular momentum is one of the most fundamental physical quantities governing galactic evolution. Differences in the colours, morphologies, star formation rates and gas fractions amongst galaxies of equal stellar/baryon mass M are potentially widely explained by variations in their specific stellar/baryon angular momentum j. The enormous potential of angular momentum science is only just being realised, thanks to the emergence of the first simulations of galaxies with converged spins, paralleled by a dramatic increase in kinematic observations. Such observations are still challenged by the fact that most of the stellar/baryon angular momentum resides at large radii. In fact, the radius that maximally contributes to the angular momentum of an exponential disk (3Re-4Re) is twice as large as the radius that maximally contributes to the disk mass; thus converged measurements of angular momentum require either extremely deep IFS data or, alternatively, kinematic measurements of neutral atomic hydrogen (HI), which ...

  17. Monitoring Global Croplands with Coarse Resolution Earth Observations: The Global Agriculture Monitoring (GLAM Project

    Directory of Open Access Journals (Sweden)

    Inbal Becker-Reshef

    2010-06-01

    Full Text Available In recent years there has been a dramatic increase in the demand for timely, comprehensive global agricultural intelligence. Timely information on global crop production is indispensable for combating the growing stress on the world’s crop production and for securing both short-term and long-term stable and reliable supply of food. Global agriculture monitoring systems are critical to providing this kind of intelligence and global earth observations are an essential component of an effective global agricultural monitoring system as they offer timely, objective, global information on croplands distribution, crop development and conditions as the growing season progresses. The Global Agriculture Monitoring Project (GLAM, a joint NASA, USDA, UMD and SDSU initiative, has built a global agricultural monitoring system that provides the USDA Foreign Agricultural Service (FAS with timely, easily accessible, scientifically-validated remotely-sensed data and derived products as well as data analysis tools, for crop-condition monitoring and production assessment. This system is an integral component of the USDA’s FAS Decision Support System (DSS for agriculture. It has significantly improved the FAS crop analysts’ ability to monitor crop conditions, and to quantitatively forecast crop yields through the provision of timely, high-quality global earth observations data in a format customized for FAS alongside a suite of data analysis tools. FAS crop analysts use these satellite data in a ‘convergence of evidence’ approach with meteorological data, field reports, crop models, attaché reports and local reports. The USDA FAS is currently the only operational provider of timely, objective crop production forecasts at the global scale. These forecasts are routinely used by the other US Federal government agencies as well as by commodity trading companies, farmers, relief agencies and foreign governments. This paper discusses the operational components

  18. Direct observation of domain walls in NiFe films using high-resolution Lorentz microscopy

    Science.gov (United States)

    Wong, Bunsen Y.; Laughlin, David E.

    1996-04-01

    A novel approach to observe the interaction between magnetic domain wall and nanoscale microstructural features is demonstrated. The method is based on Focault mode Lorentz microscopy and utilizes a Gatan energy image filter to provide additional magnification. A postexperimental image processing technique was applied to separate lattice diffraction from that induced by magnetic domains. The effect of NiFe thickness on the width of a 180° Néel wall has been studied. It was found that the thickness dependence has a similar profile to the theoretically predicted trend but the actual wall thickness is smaller than the calculated values.

  19. Merging Radar Quantitative Precipitation Estimates (QPEs) from the High-resolution NEXRAD Reanalysis over CONUS with Rain-gauge Observations

    Science.gov (United States)

    Prat, O. P.; Nelson, B. R.; Stevens, S. E.; Nickl, E.; Seo, D. J.; Kim, B.; Zhang, J.; Qi, Y.

    2015-12-01

    The processing of radar-only precipitation via the reanalysis from the National Mosaic and Multi-Sensor Quantitative (NMQ/Q2) based on the WSR-88D Next-generation Radar (Nexrad) network over the Continental United States (CONUS) is completed for the period covering from 2002 to 2011. While this constitutes a unique opportunity to study precipitation processes at higher resolution than conventionally possible (1-km, 5-min), the long-term radar-only product needs to be merged with in-situ information in order to be suitable for hydrological, meteorological and climatological applications. The radar-gauge merging is performed by using rain gauge information at daily (Global Historical Climatology Network-Daily: GHCN-D), hourly (Hydrometeorological Automated Data System: HADS), and 5-min (Automated Surface Observing Systems: ASOS; Climate Reference Network: CRN) resolution. The challenges related to incorporating differing resolution and quality networks to generate long-term large-scale gridded estimates of precipitation are enormous. In that perspective, we are implementing techniques for merging the rain gauge datasets and the radar-only estimates such as Inverse Distance Weighting (IDW), Simple Kriging (SK), Ordinary Kriging (OK), and Conditional Bias-Penalized Kriging (CBPK). An evaluation of the different radar-gauge merging techniques is presented and we provide an estimate of uncertainty for the gridded estimates. In addition, comparisons with a suite of lower resolution QPEs derived from ground based radar measurements (Stage IV) are provided in order to give a detailed picture of the improvements and remaining challenges.

  20. Mountains on Io: High-resolution Galileo observations, initial interpretations, and formation models

    Science.gov (United States)

    Turtle, E.P.; Jaeger, W.L.; Keszthelyi, L.P.; McEwen, A.S.; Milazzo, M.; Moore, J.; Phillips, C.B.; Radebaugh, J.; Simonelli, D.; Chuang, F.; Schuster, P.; Alexander, D.D.A.; Capraro, K.; Chang, S.-H.; Chen, A.C.; Clark, J.; Conner, D.L.; Culver, A.; Handley, T.H.; Jensen, D.N.; Knight, D.D.; LaVoie, S.K.; McAuley, M.; Mego, V.; Montoya, O.; Mortensen, H.B.; Noland, S.J.; Patel, R.R.; Pauro, T.M.; Stanley, C.L.; Steinwand, D.J.; Thaller, T.F.; Woncik, P.J.; Yagi, G.M.; Yoshimizu, J.R.; Alvarez Del Castillo, E.M.; Beyer, R.; Branston, D.; Fishburn, M.B.; Muller, Birgit; Ragan, R.; Samarasinha, N.; Anger, C.D.; Cunningham, C.; Little, B.; Arriola, S.; Carr, M.H.; Asphaug, E.; Morrison, D.; Rages, K.; Banfield, D.; Bell, M.; Burns, J.A.; Carcich, B.; Clark, B.; Currier, N.; Dauber, I.; Gierasch, P.J.; Helfenstein, P.; Mann, M.; Othman, O.; Rossier, L.; Solomon, N.; Sullivan, R.; Thomas, P.C.; Veverka, J.; Becker, T.; Edwards, K.; Gaddis, L.; Kirk, R.; Lee, E.; Rosanova, T.; Sucharski, R.M.; Beebe, R.F.; Simon, A.; Belton, M.J.S.; Bender, K.; Fagents, S.; Figueredo, P.; Greeley, R.; Homan, K.; Kadel, S.; Kerr, J.; Klemaszewski, J.; Lo, E.; Schwarz, W.; Williams, D.; Williams, K.; Bierhaus, B.; Brooks, S.; Chapman, C.R.; Merline, B.; Keller, J.; Tamblyn, P.; Bouchez, A.; Dyundian, U.; Ingersoll, A.P.; Showman, A.; Spitale, J.; Stewart, S.; Vasavada, A.; Breneman, H.H.; Cunningham, W.F.; Johnson, T.V.; Jones, T.J.; Kaufman, J.M.; Klaasen, K.P.; Levanas, G.; Magee, K.P.; Meredith, M.K.; Orton, G.S.; Senske, D.A.; West, A.; Winther, D.; Collins, G.; Fripp, W.J.; Head, J. W.; Pappalardo, R.; Pratt, S.; Prockter, L.; Spaun, N.; Colvin, T.; Davies, M.; DeJong, E.M.; Hall, J.; Suzuki, S.; Gorjian, Z.; Denk, T.; Giese, B.; Koehler, U.; Neukum, G.; Oberst, J.; Roatsch, T.; Tost, W.; Wagner, R.; Dieter, N.; Durda, D.; Geissler, P.; Greenberg, R.J.; Hoppa, G.; Plassman, J.; Tufts, R.; Fanale, F.P.; Granahan, J.C.

    2001-01-01

    During three close flybys in late 1999 and early 2000 the Galileo spacecraft ac-quired new observations of the mountains that tower above Io's surface. These images have revealed surprising variety in the mountains' morphologies. They range from jagged peaks several kilometers high to lower, rounded structures. Some are very smooth, others are covered by numerous parallel ridges. Many mountains have margins that are collapsing outward in large landslides or series of slump blocks, but a few have steep, scalloped scarps. From these observations we can gain insight into the structure and material properties of Io's crust as well as into the erosional processes acting on Io. We have also investigated formation mechanisms proposed for these structures using finite-element analysis. Mountain formation might be initiated by global compression due to the high rate of global subsidence associated with Io's high resurfacing rate; however, our models demonstrate that this hypothesis lacks a mechanism for isolating the mountains. The large fraction (???40%) of mountains that are associated with paterae suggests that in some cases these features are tectonically related. Therefore we have also simulated the stresses induced in Io's crust by a combination of a thermal upwelling in the mantle with global lithospheric compression and have shown that this can focus compressional stresses. If this mechanism is responsible for some of Io's mountains, it could also explain the common association of mountains with paterae. Copyright 2001 by the American Geophysical Union.

  1. High-resolution Observations of a Flux Rope with the Interface Region Imaging Spectrograph

    CERN Document Server

    Li, Ting

    2015-01-01

    We report the observations of a flux rope at transition region temperatures with the \\emph{Interface Region Imaging Spectrograph} (IRIS) on 30 August 2014. Initially, magnetic flux cancellation constantly took place and a filament was activated. Then the bright material from the filament moved southward and tracked out several fine structures. These fine structures were twisted and tangled with each other, and appeared as a small flux rope at 1330 {\\AA}, with a total twist of about 4$\\pi$. Afterwards, the flux rope underwent a counter-clockwise (viewed top-down) unwinding motion around its axis. Spectral observations of C {\\sc ii} 1335.71 {\\AA} at the southern leg of the flux rope showed that Doppler redshifts of 6$-$24 km s$^{-1}$ appeared at the western side of the axis, which is consistent with the counter-clockwise rotation motion. We suggest that the magnetic flux cancellation initiates reconnection and some activation of the flux rope. The stored twist and magnetic helicity of the flux rope are transpor...

  2. Aircraft-based observations and high-resolution simulations of an Icelandic dust storm

    Directory of Open Access Journals (Sweden)

    A.-M. Blechschmidt

    2012-11-01

    Full Text Available The first aircraft-based observations of an Icelandic dust storm are presented. The measurements were carried out over the ocean near Iceland's south coast in February 2007. This dust event occurred in conjunction with an easterly barrier jet of more than 30 m s−1. The aircraft measurements show high particle mass mixing ratios in an area of low wind speeds in the wake of Iceland near the coast, decreasing abruptly towards the jet. Simulations from the Weather Research and Forecasting Model coupled with Chemistry (WRF/Chem indicate that the measured high mass mixing ratios and observed low visibility inside the wake are due to dust transported from Icelandic sand fields towards the ocean. This is confirmed by meteorological station data. Glacial outwash terrains located near the Mýrdalsjökull glacier are among simulated dust sources. Sea salt aerosols produced by the impact of strong winds on the ocean surface started to dominate as the aircraft flew away from Iceland into the jet. The present results support recent studies which suggest that Icelandic deserts should be considered as important dust sources in global and regional climate models.

  3. Rapid ambiguity resolution over medium-to-long baselines based on GPS/BDS multi-frequency observables

    Science.gov (United States)

    Gong, Xiaopeng; Lou, Yidong; Liu, Wanke; Zheng, Fu; Gu, Shengfeng; Wang, Hua

    2017-02-01

    Medium-long baseline RTK positioning generally needs a long initial time to find an accurate position due to non-negligible atmospheric delay residual. In order to shorten the initial or re-convergence time, a rapid phase ambiguity resolution method is employed based on GPS/BDS multi-frequency observables in this paper. This method is realized by two steps. First, double-differenced un-combined observables (i.e., L1/L2 and B1/B2/B3 observables) are used to obtain a float solution with atmospheric delay estimated as random walk parameter by using Kalman filter. This model enables an easy and consistent implementation for different systems and different frequency observables and can readily be extended to use more satellite navigation systems (e.g., Galileo, QZSS). Additional prior constraints for atmospheric information can be quickly added as well, because atmospheric delay is parameterized. Second, in order to fix ambiguity rapidly and reliably, ambiguities are divided into three types (extra-wide-lane (EWL), wide-lane (WL) and narrow-lane (NL)) according to their wavelengths and are to be fixed sequentially by using the LAMBDA method. Several baselines ranging from 61 km to 232 km collected by Trimble and Panda receivers are used to validate the method. The results illustrate that it only takes approximately 1, 2 and 6 epochs (30 s intervals) to fix EWL, WL and NL ambiguities, respectively. More epochs' observables are needed to fix WL and NL ambiguity around local time 14:00 than other time mainly due to more active ionosphere activity. As for the re-convergence time, the simulated results show that 90% of epochs can be fixed within 2 epochs by using prior atmospheric delay information obtained from previously 5 min. Finally, as for positioning accuracy, meter, decimeter and centimeter level positioning results are obtained according to different ambiguity resolution performances, i.e., EWL, WL and NL fixed solutions.

  4. AngularJS directives

    CERN Document Server

    Vanston, Alex

    2013-01-01

    This book uses a practical, step-by-step approach, starting with how to build directives from the ground up before moving on to creating web applications comprised of multiple modules all working together to provide the best user experience possible.This book is intended for intermediate JavaScript developers who are looking to enhance their understanding of single-page web application development with a focus on AngularJS and the JavaScript MVC frameworks.It is expected that readers will understand basic JavaScript patterns and idioms and can recognize JSON formatted data.

  5. Multifrequency observations of a solar microwave burst with two-dimensional spatial resolution

    Science.gov (United States)

    Gary, Dale E.; Hurford, G. J.

    1990-01-01

    Frequency-agile interferometry observations using three baselines and the technique of frequency synthesis were used to obtain two-dimensional positions of multiple microwave sources at several frequency ranges in a solar flare. Source size and brightness temperature spectra were obtained near the peak of the burst. The size spectrum shows that the source size decreases rapidly with increasing frequency, but the brightness temperature spectrum can be well-fitted by gyrosynchrotron emission from a nonthermal distribution of electrons with power-law index of 4.8. The spatial structure of the burst showed several characteristics in common with primary/secondary bursts discussed by Nakajima et al. (1985). A source of coherent plasma emission at low frequencies is found near the secondary gyrosynchrotron source, associated with the leader spots of the active region.

  6. Recognition processes at a functionalized lipid surface observed with molecular resolution

    DEFF Research Database (Denmark)

    Vaknin, D.; Als-Nielsen, J.; Piepenstock, M.;

    1991-01-01

    chosen as a model system to investigate the structural characteristics of a recognition process on a molecular length scale. Changes in the neutron reflection from the surfaces of NaCl aqueous (H2O or D2O) protein solutions (10(-8) M SA) were used to monitor the interaction of the protein...... with a monolayer of a biotinylated lipid in situ. Refinement of the reflectivity data and independent fluorescence microscopic observation of the interface using FITC-labeled SA showed that the protein forms macroscopically homogeneous (and presumably crystalline) domains covering a large portion of the surface...... with each protein molecule. Quantitative binding was found to occur at biotin surface concentrations as low as 1 molecule/1,250 angstrom 2 (compared with approximately 1 molecule/40 angstrom 2 for dense packing). This study demonstrates the application of a promising new tool for the systematic...

  7. Ellerman bombs at high resolution III. Simultaneous observations with IRIS and SST

    CERN Document Server

    Vissers, Gregal J M; Rutten, Robert J; Carlsson, Mats; De Pontieu, Bart

    2015-01-01

    Ellerman bombs are transient brightenings of the extended wings of the solar Balmer lines in emerging active regions. We describe their properties in the ultraviolet lines sampled by the Interface Region Imaging Spectrograph (IRIS), using simultaneous imaging spectroscopy in H$\\alpha$ with the Swedish 1-m Solar Telescope (SST) and ultraviolet images from the Solar Dynamics Observatory for Ellerman bomb detection and identification. We select multiple co-observed Ellerman bombs for detailed analysis. The IRIS spectra strengthen the view that Ellerman bombs mark reconnection between bipolar kilogauss fluxtubes with the reconnection and the resulting bi-directional jet located within the solar photosphere and shielded by overlying chromospheric fibrils in the cores of strong lines. The spectra suggest that the reconnecting photospheric gas underneath is heated sufficiently to momentarily reach stages of ionization normally assigned to the transition region and the corona. We also analyze similar outburst phenome...

  8. Observations of PAN and its confinement in the Asian Monsoon Anticyclone in high spatial resolution

    Science.gov (United States)

    Ungermann, Joern; Ploeger, Felix; Spang, Reinhold; Riese, Martin

    2016-04-01

    This talk presents a set of observations by the CRyogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) infrared limb sounder on the SPAS platform in low-earth orbit. The spatially highly resolved trace gas measurements of six days in August 1997 allow a close look on the confinement of air masses within the Asian Summer Monsoon (ASM) anticyclone. Peroxyacetyl nitrate (PAN) is a secondary pollutant without sources in the stratosphere and acts as a tropospheric tracer. In combination with ozone as a stratospheric tracer, an eddy-shedding event of the ASM could be observed. The measured PAN volume mixing ratios (VMR) correlate well with potential vorticity (PV) derived from ECMWF ERA-Interim model data. Computing the gradient of PAN over PV on isentropes reveals that PAN VMR exhibit the strongest decrease at each isentrope for an increasing value of PV, which may be used to identify the extent of the ASM on that isentrope. CRISTA measurements also provide the temperature of measured air parcels and thus allow to derive the location of the thermal tropopause. We find that the thermal tropopause coincides with the border of the positive PAN anomaly both horizontally and vertically within the ASM anticyclone. In contrast, the shed eddy exhibits enhanced PAN VMRs for 1 to 2 km above the thermal tropopause. The amount of mixing may also be characterised by projecting the derived air parcels into tracer-tracer space using PAN and ozone as tropospheric and stratospheric tracer, respectively. This reveals that the anticyclone contains few mixed parcels in contrast to the region between the anticyclone and the shed eddy. This implies that while the anticyclone confines polluted air masses well, eddy shedding provides a very rapid horizontal transport pathway of Asian pollution into the extratropical lowermost stratosphere with a time scale of only a few days.

  9. Advancing Access to New Technology for Sustained High Resolution Observations of Plankton: From Bloom Dynamics to Climate Change

    Science.gov (United States)

    Sosik, H. M.; Olson, R. J.

    2012-12-01

    The combination of ocean observatory infrastructure and automated submersible flow cytometry can provide unprecedented capability for sustained high resolution time series of plankton, including taxa that are harmful or early indicators of ecosystem response to environmental change. Over the past decade, we have developed the FlowCytobot series of instruments that exemplify this capability. FlowCytobot and Imaging FlowCytobot use a combination of laser-based scattering and fluorescence measurements and video imaging of individual particles to enumerate and characterize cells ranging from picocyanobacteria to large chaining-forming diatoms. The process of developing these complex instruments was streamlined by access to the Martha's Vineyard Coastal Observatory (MVCO), a cabled facility on the New England Shelf, where real time two-way communications and access to shore power expedited cycles of instrument evaluation and design refinement. Repeated deployments at MVCO, typically 6 months in duration, have produced multi-year high resolution (hourly to daily) time series that are providing new insights into dynamics of community structure such as blooms, seasonality, and possibly even trends linked to regional climate change. The high temporal resolution observations of single cell properties make it possible not only to characterize taxonomic composition and size structure, but also to quantify taxon-specific growth rates. To meet the challenge of broadening access to this enabling technology, we have taken a two-step approach. First, we are partnering with a few scientific collaborators interested in using the instruments in different environments and to address different applications, notably the detection and characterization of harmful algal bloom events. Collaboration at this stage ensured that these first users outside the developers' lab had access to technical know-how required for successful outcomes; it also provided additional feedback that could be

  10. Potential for added value in precipitation simulated by high-resolution nested Regional Climate Models and observations

    Energy Technology Data Exchange (ETDEWEB)

    Di Luca, Alejandro; Laprise, Rene [Universite du Quebec a Montreal (UQAM), Centre ESCER (Etude et Simulation du Climat a l' Echelle Regionale), Departement des Sciences de la Terre et de l' Atmosphere, PK-6530, Succ. Centre-ville, B.P. 8888, Montreal, QC (Canada); De Elia, Ramon [Universite du Quebec a Montreal, Ouranos Consortium, Centre ESCER (Etude et Simulation du Climat a l' Echelle Regionale), Montreal (Canada)

    2012-03-15

    Regional Climate Models (RCMs) constitute the most often used method to perform affordable high-resolution regional climate simulations. The key issue in the evaluation of nested regional models is to determine whether RCM simulations improve the representation of climatic statistics compared to the driving data, that is, whether RCMs add value. In this study we examine a necessary condition that some climate statistics derived from the precipitation field must satisfy in order that the RCM technique can generate some added value: we focus on whether the climate statistics of interest contain some fine spatial-scale variability that would be absent on a coarser grid. The presence and magnitude of fine-scale precipitation variance required to adequately describe a given climate statistics will then be used to quantify the potential added value (PAV) of RCMs. Our results show that the PAV of RCMs is much higher for short temporal scales (e.g., 3-hourly data) than for long temporal scales (16-day average data) due to the filtering resulting from the time-averaging process. PAV is higher in warm season compared to cold season due to the higher proportion of precipitation falling from small-scale weather systems in the warm season. In regions of complex topography, the orographic forcing induces an extra component of PAV, no matter the season or the temporal scale considered. The PAV is also estimated using high-resolution datasets based on observations allowing the evaluation of the sensitivity of changing resolution in the real climate system. The results show that RCMs tend to reproduce relatively well the PAV compared to observations although showing an overestimation of the PAV in warm season and mountainous regions. (orig.)

  11. ANGULAR MOMENTUM ACQUISITION IN GALAXY HALOS

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Kyle R. [Department of Natural and Mathematical Sciences, California Baptist University, 8432 Magnolia Ave., Riverside, CA 92504 (United States); Brooks, Alyson M. [Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter St., Madison, WI 53706 (United States); Bullock, James S. [Center for Cosmology, Department of Physics and Astronomy, University of California at Irvine, Irvine, CA 92697 (United States); Maller, Ariyeh H. [Department of Physics, New York City College of Technology, 300 Jay St., Brooklyn, NY 11201 (United States); Diemand, Juerg [Institute for Theoretical Physics, University of Zurich, 8057, Zurich (Switzerland); Wadsley, James [Department of Physics and Astronomy, McMaster University, Main Street West, Hamilton L85 4M1 (Canada); Moustakas, Leonidas A. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2013-05-20

    We use high-resolution cosmological hydrodynamic simulations to study the angular momentum acquisition of gaseous halos around Milky-Way-sized galaxies. We find that cold mode accreted gas enters a galaxy halo with {approx}70% more specific angular momentum than dark matter averaged over cosmic time (though with a very large dispersion). In fact, we find that all matter has a higher spin parameter when measured at accretion than when averaged over the entire halo lifetime, and is well characterized by {lambda} {approx} 0.1, at accretion. Combined with the fact that cold flow gas spends a relatively short time (1-2 dynamical times) in the halo before sinking to the center, this naturally explains why cold flow halo gas has a specific angular momentum much higher than that of the halo and often forms ''cold flow disks.'' We demonstrate that the higher angular momentum of cold flow gas is related to the fact that it tends to be accreted along filaments.

  12. Understanding and improving mitigation strategies for reducing catchment scale nutrient loads using high resolution observations and uncertainty analysis approaches

    Science.gov (United States)

    Collins, A.; Lloyd, C.; Freer, J. E.; Johnes, P.; Stirling, M.

    2012-12-01

    One of the biggest challenges in catchment water quality management is tackling the problem of reducing water pollution from agriculture whilst ensuring food security nationally. Improvements to catchment management plans are needed if we are to enhance biodiversity and maintain good ecological status in freshwater ecosystems, while producing enough food to support a growing global population. In order to plan for a more sustainable and secure future, research needs to quantify the uncertainties and understand the complexities in the source-mobilisation-delivery-impact continuum of pollution and nutrients at all scales. In the UK the Demonstration Test Catchment (DTC) project has been set up to improve water quality specifically from diffuse pollution from agriculture by enhanced high resolution monitoring and targeted mitigation experiments. The DTC project aims to detect shifts in the baseline trend of the most ecologically-significant pollutants resulting from targeted on-farm measures at field to farm scales and assessing their effects on ecosystem function. The DTC programme involves three catchments across the UK that are indicative of three different typologies and land uses. This paper will focus on the Hampshire Avon DTC, where a total of 12 parameters are monitored by bank-side stations at two sampling sites, including flow, turbidity, phosphate and nitrate concentrations at 30 min resolution. This monitoring is supported by daily resolution sampling at 5 other sites and storm sampling at all locations. Part of the DTC project aims to understand how observations of water quality within river systems at different temporal resolutions and types of monitoring strategies enable us to understand and detect changes over and above the natural variability. Baseline monitoring is currently underway and early results show that high-resolution data is essential at this sub-catchment scale to understand important process dynamics. This is critical if we are to design

  13. The New Worlds Observer: a mission for high-resolution spectroscopy of extra-solar terrestrial planets

    Science.gov (United States)

    Simmons, Willard L.; Cash, Webster C.; Seager, Sara; Wilkinson, Erik; Kasdin, N. Jeremy; Vanderbei, Robert J.; Chow, Naomi; Gralla, Erica; Kleingeld, Johanna

    2004-10-01

    The New Worlds Observer (NWO) is a proposed space mission to provide high resolution spectroscopy from the far UV to the near IR of extra-solar terrestrial sized planets. The design of NWO is based on the concept of a large, space-based, pinhole camera made up of two spacecraft flying in formation. The first spacecraft is a large, thin occulting shield (perhaps hundreds of meters in diameter) with a shaped "pinhole" aperture about 10m in diameter. The second spacecraft is a conventional-quality space telescope (possibly with a 10m primary mirror) which "flies" through the pinhole image of the planetary system to observe the extra-solar planets free from stellar background. In this paper we describe the design of the two spacecraft system. In particular, the shaped-pinhole design utilizes the shaped-pupil coronagraph pioneered for the Terrestrial Planet Finder. In this paper we describe some of the NWO's technology challenges and science opportunities. Additionally, we describe an extension of the design to provide 100km resolution images of extra-solar planets.

  14. High time resolution observation and statistical analysis of atmospheric light extinction properties and the chemical speciation of fine particulates

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In recent years,the visibility deterioration caused by regional fine particulate pollution becomes one of the crucial air pollution problems in the urban areas of our country.The rapid variation of visibility and fine particulates make it difficult to estimate the relationship between them precisely and accurately unless high time resolution observation data can be accessed.This study aims to fill this gap in the field of atmospheric science by establishing a formula using multiple linear regressions.Excellent fitting goodness (R2=0.913,n=3167) was obtained using 10 min average of high-resolution real-time light scattering coefficients,light absorption coefficients,main chemical speciation concentration in PM1 and some meteorological parameters from 17 Jan to 16 Feb,2009.It shows that the average light extinction coefficient during the observation in the winter of Shenzhen was measured to be 290 ± 183 Mm?1,consisting of 72% of light scattering and 21% of absorption.In terms of the percentage contribution of PM1 chemical species to the total light extinction,the organic matter was estimated to be most with an average of 45%,followed by ammonium sulfate with an average of 24%.The contributions of black carbon and ammonium nitrate were 17% and 12%,respectively.Besides,the diurnal variation of light extinction was investigated as well in this study.

  15. Observation of immuno-labeled cells at high resolution using soft X-ray microscope at Ritsumeikan University SR Center

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, A [Nagahama Institute of Bio-Science and Technology, 1266, Tamura-cho, Nagahama, Shiga, 526-0829 (Japan); Takemoto, K; Kihara, H [Department of Physics, Kansai Medical University, 18-89 Uyamahigashi, Hirakata, Osaka, 573-1136 (Japan); Fukui, T; Yoshimura, Y; Namba, H [Department of Physical Science, Ritsumeikan University, 1-1-1, Noji-Higashi, Kusatsu, Shiga, 525-8577 (Japan); Okuno, K, E-mail: takemoto@makino.kmu.ac.j [SR Center, Ritsumeikan University, 1-1-1, Noji-Higashi Kusatsu, Shiga, 525-8577 (Japan)

    2009-09-01

    Mouse fibroblast cell line NIH3T3 cells were labeled with the heavy metal (silver and gold) and observed intracellular structure under an X-ray microscope. Microtubules, Golgi apparatus and early endosomes of NIH3T3 cells were stained with immuno-gold nanoparticles, and immuno-staining was intensified by silver or gold enhancement procedure. Using a transmission soft X-ray microscope beamline (BL12) at Ritsumeikan University SR center, we observed immuno-stained NIH3T3 cells with several wavelengths just below and above oxygen edge ({lambda} = 2.32 nm). Using this method, cytoskeleton (microtubules) and organelles (Golgi apparatus and early endosomes) were successfully imaged with high resolution. Thus, immuno-gold silver and gold enhancement technique is useful for specific labeling of intracellular structure under an X-ray microscope.

  16. Observation of immuno-labeled cells at high resolution using soft X-ray microscope at Ritsumeikan University SR Center

    Science.gov (United States)

    Yamamoto, A.; Takemoto, K.; Fukui, T.; Yoshimura, Y.; Okuno, K.; Namba, H.; Kihara, H.

    2009-09-01

    Mouse fibroblast cell line NIH3T3 cells were labeled with the heavy metal (silver and gold) and observed intracellular structure under an X-ray microscope. Microtubules, Golgi apparatus and early endosomes of NIH3T3 cells were stained with immuno-gold nanoparticles, and immuno-staining was intensified by silver or gold enhancement procedure. Using a transmission soft X-ray microscope beamline (BL12) at Ritsumeikan University SR center, we observed immuno-stained NIH3T3 cells with several wavelengths just below and above oxygen edge (λ = 2.32 nm). Using this method, cytoskeleton (microtubules) and organelles (Golgi apparatus and early endosomes) were successfully imaged with high resolution. Thus, immuno-gold silver and gold enhancement technique is useful for specific labeling of intracellular structure under an X-ray microscope.

  17. Herschel observations of EXtra-Ordinary Sources: The Terahertz spectrum of Orion KL seen at high spectral resolution

    CERN Document Server

    Crockett, N R; Wang, S; Lis, D C; Bell, T A; Blake, G A; Boogert, A; Bumble, B; Cabrit, S; Caux, E; Ceccarelli, C; Cernicharo, J; Comito, C; Daniel, F; Dubernet, M -L; Emprechtinger, M; Encrenaz, P; Falgarone, E; Gerin, M; Giesen, T F; Goicoechea, J R; Goldsmith, P F; Gupta, H; Gusten, R; Hartogh, P; Helmich, F; Herbst, E; Honingh, N; Joblin, C; Johnstone, D; Karpov, A; Kawamura, J H; Kooi, J; Krieg, J -M; Langer, W D; Latter, W D; Lord, S D; Maret, S; Martin, P G; Melnick, G J; Menten, K M; Morris, P; Muller, H S P; Murphy, J A; Neufeld, D A; Ossenkopf, V; Pearson, J C; Perault, M; Phillips, T G; Plume, R; Qin, S -L; Roelfsema, P; Schieder, R; Schilke, P; Schlemmer, S; Stutzki, J; van der Tak, F F S; Tielens, A; Trappe, N; Vastel, C; Yorke, H W; Yu, S; Zmuidzinas, J

    2010-01-01

    We present the first high spectral resolution observations of Orion KL in the frequency ranges 1573.4 - 1702.8 GHz (band 6b) and 1788.4 - 1906.8 GHz (band 7b) obtained using the HIFI instrument on board the Herschel Space Observatory. We characterize the main emission lines found in the spectrum, which primarily arise from a range of components associated with Orion KL including the hot core, but also see widespread emission from components associated with molecular outflows traced by H2O, SO2, and OH. We find that the density of observed emission lines is significantly diminished in these bands compared to lower frequency Herschel/HIFI bands.

  18. CHIRON TOOLS: Integrated Target Submission, Scheduling and Observing Systems for a High-Resolution Fiber-Fed Spectrograph

    Science.gov (United States)

    Brewer, John M.; Giguere, Matthew; Fischer, Debra A.

    2014-01-01

    The CHIRON spectrometer is a new high-resolution, fiber-fed instrument on the 1.5 m telescope at Cerro Tololo Inter-America Observatory (CTIO). To optimize use of the instrument and limited human resources, we have designed an integrated set of Web applications allowing target submission, observing script planning, nightly script execution and logging, and access to reduced data by multiple users. The unified and easy-to-use interface has dramatically reduced the time needed to submit and schedule observations and improved the efficiency and accuracy of nightly operations. We present our experience to help astronomers and project managers who need to plan for the scope of effort required to commission a queue-scheduled facility instrument.

  19. High Resolution X-ray Imaging Observations of two low luminosity Seyfert Galaxies

    CERN Document Server

    Singh, K P

    1999-01-01

    An extended component of X-ray emission has been detected in Seyfert galaxies - NGC 1365 and NGC 4051, using the ROSAT HRI. Its size is about 2 kpc and it contains 56% +- 8% of the total observed flux in NGC 1365, and 21% +- 6% in NGC 4051. Extended emission in NGC 1365 is aligned with the inner disk structure, has wings along the east and west direction aligned with the inner spiral arms, and has an elongated edge-brightened structure (``chimney'') breaking out of the disk in the north-west direction. In NGC 4051 it is co-spatial with the disk of the galaxy, and shows an elongation coincident with a ``banana''-like feature in the north-east seen in the 6 cm radio band. Starburst activity driving strong winds through the disk of NGC 1365 can account for most of the extended soft X-ray emission in it. Both nuclear activity and starburst induced activity maybe needed to explain extended X-ray emission in NGC 4051. The nuclear component of NGC 4051 shows soft X-ray variability with X-ray intensity changing by a ...

  20. Coastal High-resolution Observations and Remote Sensing of Ecosystems (C-HORSE)

    Science.gov (United States)

    Guild, Liane

    2016-01-01

    Coastal benthic marine ecosystems, such as coral reefs, seagrass beds, and kelp forests are highly productive as well as ecologically and commercially important resources. These systems are vulnerable to degraded water quality due to coastal development, terrestrial run-off, and harmful algal blooms. Measurements of these features are important for understanding linkages with land-based sources of pollution and impacts to coastal ecosystems. Challenges for accurate remote sensing of coastal benthic (shallow water) ecosystems and water quality are complicated by atmospheric scattering/absorption (approximately 80+% of the signal), sun glint from the sea surface, and water column scattering (e.g., turbidity). Further, sensor challenges related to signal to noise (SNR) over optically dark targets as well as insufficient radiometric calibration thwart the value of coastal remotely-sensed data. Atmospheric correction of satellite and airborne remotely-sensed radiance data is crucial for deriving accurate water-leaving radiance in coastal waters. C-HORSE seeks to optimize coastal remote sensing measurements by using a novel airborne instrument suite that will bridge calibration, validation, and research capabilities of bio-optical measurements from the sea to the high altitude remote sensing platform. The primary goal of C-HORSE is to facilitate enhanced optical observations of coastal ecosystems using state of the art portable microradiometers with 19 targeted spectral channels and flight planning to optimize measurements further supporting current and future remote sensing missions.

  1. VLBI observations of two single dMe stars spatial resolution and astrometry

    CERN Document Server

    Pestalozzi, M R; Conway, J E; Güdel, M

    2000-01-01

    We report on 3.6 cm VLA and VLBA observations of YZ CMi and AD Leo, two nearby dMe stars. We resolve YZ CMi and can fit a circular symmetrical gaussian component of FWHP of 0.98 +/-0.2 mas, corresponding to an extent of the corona above the photosphere of 1.77 x 10^{10} +/-8.8 x 10^{9} cm or 0.7 +/-0.3 Rstar (Rstar refers to the photospheric radius). We obtain an estimate of the brightness temperature of 7.3 x 10^{7} K, which is consistent with that expected from gyrosynchrotron emission. For AD Leo the emitting region is unresolved. We therefore set a conservative upper limit to its diameter of 1.8 times the photosphere diameter, which leads to an extent of the corona above the photosphere of <2.8 x 10^{10} cm or <0.8 Rstar. We compare the radio emitting dMe stars with measured sizes with the Sun and conclude that these active stars have much more extended coronal radio emission than the Sun. The VLBA position of YZ CMi has been found to differ by 32 mas from the positions calculated from the Hipparcos...

  2. High Spectral and Spatial Resolution Observations of Shocked Molecular Hydrogen at the Galactic Center

    CERN Document Server

    Yusef-Zadeh, F; Burton, M; Wardle, M; Ashley, M C B

    2001-01-01

    The presence of OH (1720 MHz) masers, and the absence of counterparts at 1665/1667 MHz has proved to be a clear diagnostic of shocked molecular gas associated with Galactic supernova remnants. This suggests that shocked molecular gas should be associated with the OH (1720 MHz) masers that have been detected in the circumnuclear disk (CND) and Sgr A East at the Galactic center. In order to test this hypothesis, we observed the H$_2$ 1--0 S(1) and Br $\\gamma$ lines using NICMOS on the HST and UNSWIRF on the AAT, near the regions where OH (1720 MHz) masers are detected in the CND and Sgr A East. We present the distribution of H$_2$ in the North and South lobes of the CND and in Sgr A East. H$_2$ emission accompanies almost all of the maser spots detected at the Galactic center. In particular, we find a striking filamentary structure near the Northwest of the CND and evidence that shocked molecular gas is associated with the 70 \\kms molecular cloud at the Galactic center. We argue that the emission from the CND c...

  3. Observation of lens aberrations for high resolution electron microscopy II: Simple expressions for optimal estimates

    Energy Technology Data Exchange (ETDEWEB)

    Saxton, W. Owen, E-mail: wos1@cam.ac.uk

    2015-04-15

    This paper lists simple closed-form expressions estimating aberration coefficients (defocus, astigmatism, three-fold astigmatism, coma / misalignment, spherical aberration) on the basis of image shift or diffractogram shape measurements as a function of injected beam tilt. Simple estimators are given for a large number of injected tilt configurations, optimal in the sense of least-squares fitting of all the measurements, and so better than most reported previously. Standard errors are given for most, allowing different approaches to be compared. Special attention is given to the measurement of the spherical aberration, for which several simple procedures are given, and the effect of foreknowledge of this on other aberration estimates is noted. Details and optimal expressions are also given for a new and simple method of analysis, requiring measurements of the diffractogram mirror axis direction only, which are simpler to make than the focus and astigmatism measurements otherwise required. - Highlights: • Optimal estimators for CTEM lens aberrations are more accurate and/or use fewer observations. • Estimators have been found for defocus, astigmatism, three-fold astigmatism, coma and spherical aberration. • Estimators have been found relying on diffractogram shape, image shift and diffractogram orientation only, for a variety of beam tilts. • The standard error for each estimator has been found.

  4. A new active array MST radar system with enhanced capabilities for high resolution atmospheric observations

    Science.gov (United States)

    Durga rao, Meka; Jayaraman, Achuthan; Patra, Amit; Venkat Ratnam, Madineni; Narayana Rao, T.; Kamaraj, Pandian; Jayaraj, Katta; Kmv, Prasad; Kamal Kumar, J.; Raghavendra, J.; Prasad, T. Rajendra; Thriveni, A.; Yasodha, Polisetti

    2016-07-01

    A new version of the 53-MHz MST Radar, using the 1024 solid state Transmit-Receive Modules (TRM), necessary feeder network, multi-channel receiver and a modified radar controller has been established using the existing antenna array of 1024 crossed Yagis. The new system has been configured for steering the beam on a pulse-to-pulse basis in all 360o azimuth and 20o zenith angle, providing enhanced capability to study the Mesosphere-Stratosphere-Troposphere and Ionosphere. The multi channel receiver system has been designed for Spaced Antenna (SA) and Interferometry/ Iamging applications. The new system has also been configured for radiating in circular polarization for its application in the Ionosphere Incoherent Scatter mode. The new active array MST radar at Very-High-Frequency (53-MHz) located at Gadanki (13.45°N, 79.18°E), a tropical station in India, will be used to enhance the observations of winds, turbulence during the passage of convective events over the radar site as deep convection occurs very often at tropical latitudes. The new configuration with enhanced average power, beam agility with multi-channel experiments will be a potential source for studying middle atmosphere and ionosphere. In this paper, we present the system configuration, new capabilities and the first results obtained using the new version of the MST Radar.

  5. Sustaining persistent lava lakes: Observations from high-resolution gas measurements at Villarrica volcano, Chile

    Science.gov (United States)

    Moussallam, Yves; Bani, Philipson; Curtis, Aaron; Barnie, Talfan; Moussallam, Manuel; Peters, Nial; Schipper, C. Ian; Aiuppa, Alessandro; Giudice, Gaetano; Amigo, Álvaro; Velasquez, Gabriela; Cardona, Carlos

    2016-11-01

    Active lava lakes - as the exposed upper part of magmatic columns - are prime locations to investigate the conduit flow processes operating at active, degassing volcanoes. Persistent lava lakes require a constant influx of heat to sustain a molten state at the Earth's surface. Several mechanisms have been proposed to explain how such heat transfer can operate efficiently. These models make contrasting predictions with respect to the flow dynamics in volcanic conduits and should result in dissimilar volatile emissions at the surface. Here we look at high-frequency SO2 fluxes, plume composition, thermal emissions and aerial video footage from the Villarrica lava lake in order to determine the mechanism sustaining its activity. We found that while fluctuations are apparent in all datasets, none shows a stable periodic behaviour. These observations suggest a continuous influx of volatiles and magma to the Villarrica lava lake. We suggest that ascending volatile-rich and descending degassed magmas are efficiently mixed within the volcanic conduit, resulting in no clear periodic oscillations in the plume composition and flux. We compare our findings to those of other lava lakes where equivalent gas emission time-series have been acquired, and suggest that gas flux, magma viscosity and conduit geometry are key parameters determining which flow mechanism operates in a given volcanic conduit. The range of conduit flow regimes inferred from the few studied lava lakes gives a glimpse of the potentially wide spectrum of conduit flow dynamics operating at active volcanoes.

  6. High spatial resolution mid-infrared observations of the low-mass young star TW Hya

    CERN Document Server

    Ratzka, T; Henning, T; Bouwman, J; Dullemond, C P; Jaffe, W

    2007-01-01

    We want to improve knowledge of the structure of the inner few AU of the circumstellar disk around the nearby T Tauri star TW Hya. Earlier studies have suggested the existence of a large inner hole, possibly caused by interactions with a growing protoplanet. We used interferometric observations in the N-band obtained with the MIDI instrument on the Very Large Telescope Interferometer, together with 10 micron spectra recorded by the infrared satellite Spitzer. The fact that we were able to determine N-band correlated fluxes and visibilities for this comparatively faint source shows that MIR interferometry can be applied to a large number of low-mass young stellar objects. The MIR spectra obtained with Spitzer reveal emission lines from HI (6-5), HI (7-6), and [Ne II] and show that over 90% of the dust we see in this wavelength regime is amorphous. According to the correlated flux measured with MIDI, most of the crystalline material is in the inner, unresolved part of the disk, about 1 AU in radius. The visibil...

  7. The Kepler Follow-up Observation Program. I. A Catalog of Companions to Kepler Stars from High-Resolution Imaging

    Science.gov (United States)

    Furlan, E.; Ciardi, D. R.; Everett, M. E.; Saylors, M.; Teske, J. K.; Horch, E. P.; Howell, S. B.; van Belle, G. T.; Hirsch, L. A.; Gautier, T. N., III; Adams, E. R.; Barrado, D.; Cartier, K. M. S.; Dressing, C. D.; Dupree, A. K.; Gilliland, R. L.; Lillo-Box, J.; Lucas, P. W.; Wang, J.

    2017-02-01

    We present results from high-resolution, optical to near-IR imaging of host stars of Kepler Objects of Interest (KOIs), identified in the original Kepler field. Part of the data were obtained under the Kepler imaging follow-up observation program over six years (2009–2015). Almost 90% of stars that are hosts to planet candidates or confirmed planets were observed. We combine measurements of companions to KOI host stars from different bands to create a comprehensive catalog of projected separations, position angles, and magnitude differences for all detected companion stars (some of which may not be bound). Our compilation includes 2297 companions around 1903 primary stars. From high-resolution imaging, we find that ∼10% (∼30%) of the observed stars have at least one companion detected within 1″ (4″). The true fraction of systems with close (≲4″) companions is larger than the observed one due to the limited sensitivities of the imaging data. We derive correction factors for planet radii caused by the dilution of the transit depth: assuming that planets orbit the primary stars or the brightest companion stars, the average correction factors are 1.06 and 3.09, respectively. The true effect of transit dilution lies in between these two cases and varies with each system. Applying these factors to planet radii decreases the number of KOI planets with radii smaller than 2 {R}\\oplus by ∼2%–23% and thus affects planet occurrence rates. This effect will also be important for the yield of small planets from future transit missions such as TESS.

  8. Observations of PAN and its confinement in the Asian summer monsoon anticyclone in high spatial resolution

    Science.gov (United States)

    Ungermann, Jörn; Ern, Mandfred; Kaufmann, Martin; Müller, Rolf; Spang, Reinhold; Ploeger, Felix; Vogel, Bärbel; Riese, Martin

    2016-07-01

    This paper presents an analysis of trace gases in the Asian summer monsoon (ASM) region on the basis of observations by the CRISTA infrared limb sounder taken in low-earth orbit in August 1997. The spatially highly resolved measurements of peroxyacetyl nitrate (PAN) and O3 allow a detailed analysis of an eddy-shedding event of the ASM anticyclone. We identify enhanced PAN volume mixing ratios (VMRs) within the main anticyclone and within the eddy, which are suitable as a tracer for polluted air originating in India and China. Plotting the retrieved PAN VMRs against potential vorticity (PV) and potential temperature reveals that the PV value at which the PAN VMRs exhibit the strongest decrease with respect to PV increases with potential temperature. These PV values might be used to identify the extent of the ASM. Using temperature values also derived from CRISTA measurements, we also computed the location of the thermal tropopause according to the WMO criterion and find that it confines the PAN anomaly vertically within the main ASM anticyclone. In contrast, the shed eddy exhibits enhanced PAN VMRs for 1 to 2 km above the thermal tropopause. Using the relationship between PAN as a tropospheric tracer and O3 as a stratospheric tracer to identify mixed air parcels, we further found the anticyclone to contain few such air parcels, whereas the region between the anticyclone and the eddy as well as the eddy itself contains many mixed air parcels. In combination, this implies that while the anticyclone confines polluted air masses well, eddy shedding provides a very rapid horizontal transport pathway of Asian pollution into the extratropical lowermost stratosphere with a timescale of only a few days.

  9. High resolution observations of sporadic-E layers within the polar cap ionosphere using a new incoherent scatter radar experiment

    Directory of Open Access Journals (Sweden)

    B. Damtie

    Full Text Available High resolution observations of sporadic-E layers using a new experiment with the EISCAT (European Incoherent SCATter Svalbard radar (ESR are presented. The observations were made by means of a new type of hardware, which was connected in parallel with the standard receiver. The radar beam was aligned with the geomagnetic field. The experiment applies a new modulation principle. Two phase codes, one with 22 bits and the other with 5 bits, were transmitted at separate frequencies. Each bit was further modulated by a 5-bit Barker code. The basic bit length of both transmissions was 6 µs. Instead of storing the lagged products of the ionospheric echoes in the traditional way, samples of both the transmitted pulses and the ionospheric echoes were taken at intervals of 1 µs and stored on hard disk. The lagged products were calculated later in an off-line analysis. In the analysis a sidelobe-free Barker decoding technique was used. The experiment produces range ambiguities, which were removed by mathematical inversion. Sporadic-E layers were observed at 105–115 km altitudes, and they are displayed with a 150-m range resolution and a 10-s time resolution. The layers show sometimes complex shapes, including triple peaked structures. The thickness of these sublayers is of the order of 1–2 km and they may be separated by 5 km in range. While drifting downwards, the sublayers merge together to form a single layer. The plasma inside a layer is found to have a longer correlation length than that of the surrounding plasma. This may be an indication of heavy ions inside the layer. The field-aligned ion velocity is also calculated. It reveals shears in the meridional wind, which suggests that shears probably also exist in the zonal wind. Hence the wind shear mechanism is a possible generation mechanism of the layer. However, observations from the coherent SuperDARN radar indicate the presence of an ionospheric electric field pointing in the sector between

  10. On the vector model of angular momentum

    Science.gov (United States)

    Saari, Peeter

    2016-09-01

    Instead of (or in addition to) the common vector diagram with cones, we propose to visualize the peculiarities of quantum mechanical angular momentum by a completely quantized 3D model. It spotlights the discrete eigenvalues and noncommutativity of components of angular momentum and corresponds to outcomes of measurements—real or computer-simulated. The latter can be easily realized by an interactive worksheet of a suitable program package of algebraic calculations. The proposed complementary method of visualization helps undergraduate students to better understand the counterintuitive properties of this quantum mechanical observable.

  11. Angular momentum and the electromagnetic top

    Indian Academy of Sciences (India)

    GIANFRANCO SPAVIERI; GEORGE T GILLIES

    2016-08-01

    The electric charge–magnetic dipole interaction is considered. If $\\Gamma_{\\rm em}$ is the electromagnetic and $\\Gamma_{\\rm mech}$ the mechanical angular momentum, the conservation law for the total angular momentum $\\Gamma_{\\rm tot}$ holds: $\\Gamma_{\\rm tot}$ =$\\Gamma_{\\rm em}$ + $\\Gamma_{\\rm mech}$ = ${\\rm const.}$, but when the dipole moment varies with time, $\\Gamma_{\\rm mech}$ is not conserved. We show that the non-conserved $\\Gamma_{\\rm mech}$ of such a macroscopic isolated system might be experimentally observable. With advanced technology, the strength of the interaction hints to the possibility of novel applications for gyroscopes, such as the electromagnetic top.

  12. Ultrafast angular momentum transfer in multisublattice ferrimagnets.

    Science.gov (United States)

    Bergeard, N; López-Flores, V; Halté, V; Hehn, M; Stamm, C; Pontius, N; Beaurepaire, E; Boeglin, C

    2014-03-11

    Femtosecond laser pulses can be used to induce ultrafast changes of the magnetization in magnetic materials. However, one of the unsolved questions is that of conservation of the total angular momentum during the ultrafast demagnetization. Here we report the ultrafast transfer of angular momentum during the first hundred femtoseconds in ferrimagnetic Co0.8Gd0.2 and Co0.74Tb0.26 films. Using time-resolved X-ray magnetic circular dichroism allowed for time-resolved determination of spin and orbital momenta for each element. We report an ultrafast quenching of the magnetocrystalline anisotropy and show that at early times the demagnetization in ferrimagnetic alloys is driven by the local transfer of angular momenta between the two exchange-coupled sublattices while the total angular momentum stays constant. In Co0.74Tb0.26 we have observed a transfer of the total angular momentum to an external bath, which is delayed by ~150 fs.

  13. Orbital angular momentum microlaser

    Science.gov (United States)

    Miao, Pei; Zhang, Zhifeng; Sun, Jingbo; Walasik, Wiktor; Longhi, Stefano; Litchinitser, Natalia M.; Feng, Liang

    2016-07-01

    Structured light provides an additional degree of freedom for modern optics and practical applications. The effective generation of orbital angular momentum (OAM) lasing, especially at a micro- and nanoscale, could address the growing demand for information capacity. By exploiting the emerging non-Hermitian photonics design at an exceptional point, we demonstrate a microring laser producing a single-mode OAM vortex lasing with the ability to precisely define the topological charge of the OAM mode. The polarization associated with OAM lasing can be further manipulated on demand, creating a radially polarized vortex emission. Our OAM microlaser could find applications in the next generation of integrated optoelectronic devices for optical communications in both quantum and classical regimes.

  14. Source geometry from exceptionally high resolution long period event observations at Mt Etna during the 2008 eruption

    CERN Document Server

    De Barros, Louis; Lokmer, Ivan; Saccorotti, Gilberto; Zucarello, Luciano; O'Brien, Gareth; Métaxian, Jean-Philippe; Patanè, Domenico; 10.1029/2009GL041273

    2010-01-01

    During the second half of June, 2008, 50 broadband seismic stations were deployed on Mt Etna volcano in close proximity to the summit, allowing us to observe seismic activity with exceptionally high resolution. 129 long period events (LP) with dominant frequencies ranging between 0.3 and 1.2 Hz, were extracted from this dataset. These events form two families of similar waveforms with different temporal distributions. Event locations are performed by cross-correlating signals for all pairs of stations in a two-step scheme. In the first step, the absolute location of the centre of the clusters was found. In the second step, all events are located using this position. The hypocentres are found at shallow depths (20 to 700 m deep) below the summit craters. The very high location resolution allows us to detect the temporal migration of the events along a dike-like structure and 2 pipe shaped bodies, yielding an unprecedented view of some elements of the shallow plumbing system at Mount Etna. These events do not s...

  15. Microfabric and anisotropy of elastic waves in sandstone - An observation using high-resolution X-ray microtomography

    Science.gov (United States)

    Kahl, Wolf-Achim; Hinkes, Robert; Feeser, Volker; Holzheid, Astrid

    2013-04-01

    Petrophysical experiments, using acoustic velocities to characterise anisotropies of mechanical behaviour of rocks are of essential relevance to understand the geomechanical behaviour of sandstone reservoirs under changing stress fields. Here, we present high-resolution X-ray microtomography (μ-CT) as a supplementary research tool to interpret anisotropic ultrasound velocities in sandstones with variation of isotopic stress. Specimens of two Lower Cretaceous sandstones (localities Bentheim and Obernkirchen, both Germany) have been used in petrophysical laboratory experiments under dry conditions to study ultrasonic sound velocities (frequency of signal input 1 MHz). Subsequently, oriented micro-plugs drilled from the sandstone samples were investigated using high-resolution X-ray microtomography. By means of image processing of the reconstructed scan images, geometric attributes such as mean structural thickness, orientation and tortuosity were evaluated from the μ-CT data for both pore space and grain skeleton. Our observations clearly indicate the different roles of pore space and grain skeleton in regard to the propagation of ultrasonic waves: because the pores do not transmit the waves, it was sufficient to investigate the average thickness of this fabric element. In contrast, as the ultrasonic waves traverse the rock via the adjacent grains, it was necessary to survey the actual travel lengths of seismic waves in the sandstone grain skeleton.

  16. High resolution observations of the near-surface wind field over an isolated mountain and in a steep river canyon

    Directory of Open Access Journals (Sweden)

    B. W. Butler

    2014-06-01

    Full Text Available A number of numerical wind flow models have been developed for simulating wind flow at relatively fine spatial resolutions (e.g., ∼100 m; however, there are very limited observational data available for evaluating these high resolution models. This study presents high-resolution surface wind datasets collected from an isolated mountain and a steep river canyon. The wind data are presented in terms of four flow regimes: upslope, afternoon, downslope, and a synoptically-driven regime. There were notable differences in the data collected from the two terrain types. For example, wind speeds collected on the isolated mountain increased with distance upslope during upslope flow, but generally decreased with distance upslope at the river canyon site during upslope flow. Wind speed did not have a simple, consistent trend with position on the slope during the downslope regime on the isolated mountain, but generally increased with distance upslope at the river canyon site. The highest measured speeds occurred during the passage of frontal systems on the isolated mountain. Mountaintop winds were often twice as high as wind speeds measured on the surrounding plain. The highest speeds measured in the river canyon occurred during late morning hours and were from easterly downcanyon flows, presumably associated with surface pressure gradients induced by formation of a regional thermal trough to the west and high pressure to the east. Under periods of weak synoptic forcing, surface winds tended to be decoupled from large-scale flows, and under periods of strong synoptic forcing, variability in surface winds was sufficiently large due to terrain-induced mechanical effects (speed-up over ridges and decreased speeds on leeward sides of terrain obstacles that a large-scale mean flow would not be representative of surface winds at most locations on or within the terrain feature. These findings suggest that traditional operational weather model (i.e., with

  17. Mapping High-Resolution Soil Moisture over Heterogeneous Cropland Using Multi-Resource Remote Sensing and Ground Observations

    Directory of Open Access Journals (Sweden)

    Lei Fan

    2015-10-01

    Full Text Available High spatial resolution soil moisture (SM data are crucial in agricultural applications, river-basin management, and understanding hydrological processes. Merging multi-resource observations is one of the ways to improve the accuracy of high spatial resolution SM data in the heterogeneous cropland. In this paper, the Bayesian Maximum Entropy (BME methodology is implemented to merge the following four types of observed data to obtain the spatial distribution of SM at 100 m scale: soil moisture observed by wireless sensor network (WSN, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER-derived soil evaporative efficiency (SEE, irrigation statistics, and Polarimetric L-band Multi-beam Radiometer (PLMR-derived SM products (~700 m. From the poor BME predictions obtained by merging only WSN and SEE data, we observed that the SM heterogeneity caused by irrigation and the attenuating sensitivity of the SEE data to SM caused by the canopies result in BME prediction errors. By adding irrigation statistics to the merged datasets, the overall RMSD of the BME predictions during the low-vegetated periods can be successively reduced from 0.052 m3·m−3 to 0.033 m3·m−3. The coefficient of determination (R2 and slope between the predicted and in situ measured SM data increased from 0.32 to 0.64 and from 0.38 to 0.82, respectively, but large estimation errors occurred during the moderately vegetated periods (RMSD = 0.041 m3·m−3, R = 0.43 and the slope = 0.41. Further adding the downscaled SM information from PLMR SM products to the merged datasets, the predictions were satisfactorily accurate with an RMSD of 0.034 m3·m−3, R2 of 0.4 and a slope of 0.69 during moderately vegetated periods. Overall, the results demonstrated that merging multi-resource observations into SM estimations can yield improved accuracy in heterogeneous cropland.

  18. Mini-MegaTORTORA wide-field monitoring system with sub-second temporal resolution: observation of transient events

    Science.gov (United States)

    Karpov, S.; Beskin, G.; Biryukov, A.; Bondar, S.; Ivanov, E.; Katkova, E.; Perkov, A.; Sasyuk, V.

    2016-06-01

    Here we present a summary of first years of operation and first results of a novel 9-channel wide-field optical monitoring system with sub-second temporal resolution, Mini-MegaTORTORA (MMT-9), which is in operation now at Special Astrophysical Observatory on Russian Caucasus. The system is able to observe the sky simultaneously in either wide (~900 square degrees) or narrow (~100 square degrees) fields of view, either in clear light or with any combination of color (Johnson-Cousins B, V or R) and polarimetric filters installed, with exposure times ranging from 0.1 s to hundreds of seconds. The real-time system data analysis pipeline performs automatic detection of rapid transient events, both near-Earth and extragalactic. The objects routinely detected by MMT include faint meteors and artificial satellites. The pipeline for a longer time scales variability analysis is still in development.

  19. Relationship Between Solar Coronal X-Ray Brightness and Active Region Magnetic Fields: A Study Using High Resolution Observations

    CERN Document Server

    Hazra, Soumitra; Ravindra, B

    2014-01-01

    By utilizing high resolution observations of nearly co-temporal and co-spatial SOT spectropolarimeter and XRT coronal X-ray data onboard Hinode, we revisit the contentious issue of the relationship between global magnetic quantities and coronal X-ray intensity. Co-aligned vector magnetogram and X-ray data are used for this study. We find that there is no pixel-to-pixel correlation between the observed loop brightness and magnetic quantities. However, the X-ray brightness is well correlated with the integrated magnetic quantities such as total unsigned magnetic flux, total unsigned vertical current, area integrated square of the vertical magnetic field and horizontal magnetic fields. Comparing all these quantities we find that the total magnetic flux correlates well with the observed integrated X-ray brightness, though there is some differences in the strength of the correlation when we use the X-ray data from different filters. While we get a good correlation between X-ray brightness and total unsigned vertic...

  20. WESTERBORK OBSERVATIONS OF HIGH-VELOCITY CLOUDS - THE DATA

    NARCIS (Netherlands)

    WAKKER, BP

    1991-01-01

    The results of Westerbork * observations of small-scale structure in high-velocity clouds (HVCs) at 1' angular and 1 km s-1 velocity resolution are presented in the form of a table of observational parameters, maps of hydrogen column density, velocity-right ascension cuts, and histograms of the line

  1. Ambient Observations of Organic Nitrogen Compounds in Submicrometer Aerosols in New York Using High Resolution Aerosol Mass Spectrometry

    Science.gov (United States)

    Zhou, S.; Ge, X.; Xu, J.; Sun, Y.; Zhang, Q.

    2015-12-01

    Organic nitrogen (ON) compounds, which include amines, nitriles, organic nitrates, amides, and N-containing aromatic heterocycles, are an important class of compounds ubiquitously detected in atmospheric particles and fog and cloud droplets. Previous studies indicate that these compounds can make up a significant fraction (20-80%) of the total nitrogen (N) content in atmospheric condensed phases and play important roles in new particle formation and growth and affecting the optical and hygroscopicity of aerosols. In this study, we report the observation of ON compounds in submicrometer particles (PM1) at two locations in New York based on measurements using Aerodyne high-resolution time-of-flight mass spectrometer (HR-ToF-AMS). One study was conducted as part of the US Department of Energy funded Aerosol Lifecyle - Intensive Operation Period (ALC-IOP) campaign at Brookhaven National Lab (BNL, 40.871˚N, 72.89˚W) in summer, 2011 and the other was conducted at the Queen's College (QC) in New York City (NYC) in summer, 2009. We observed a notable amount of N-containing organic fragment ions, CxHyNp+ and CxHyOzNp+, in the AMS spectra of organic aerosols at both locations and found that they were mainly associated with amino functional groups. Compared with results from lab experiments, the C3H8N+ at m/z = 58 was primarily attributed to trimethylamine. In addition, a significant amount of organonitrates was observed at BNL. Positive matrix factorization (PMF) analysis of the high resolution mass spectra (HRMS) of organic aerosols identified a unique nitrogen-enriched OA (NOA) factor with elevated nitrogen-to-carbon (N/C) at both BNL and QC. Analysis of the size distributions, volatility profiles, and correlations with external tracer indicates that acid-base reactions of amino compounds with sulfate and acidic gas were mainly responsible for the formation of amine salts. Photochemical production was also observed to play a role in the formation of NOA. Bivariate polar

  2. First observations of the second solar spectrum with spatial resolution at the Lunette Jean Rösch

    Science.gov (United States)

    Malherbe, J.-M.; Moity, J.; Arnaud, J.; Roudier, Th.

    2007-02-01

    Context: A new polarimeter has been installed at the focus of the 50 cm refractor of the Lunette Jean Rösch (LJR), previously known as Turret Dome, Pic du Midi, France, for spectroscopic observations of weak solar magnetic fields. Fields can be derived through the Hanle effect from the depolarization of the second solar spectrum (i.e. the linearly polarized spectrum at the limb). Aims: We present the first observations with spatial resolution based on the new device performed with the large 8 m Echelle spectrograph, or recorded in imagery mode through narrow band filters. The observations started in April 2004, especially in the blue part of the spectrum where our instrumentation has a particularly good efficiency. The capabilities and the characteristics of the new instrument are briefly described. We observed several lines of the second solar spectrum with the slit of the spectrograph orthogonal to the limb to study the polarization as a function of limb distance (which is related to altitude in the atmosphere), and several spectral windows in imagery to determine the average continuum polarization. Methods: The polarimeter uses Nematic Liquid Crystal (NLC) technology at the primary focus of the refractor, in spectroscopic or imagery mode. Results: A continuous polarization profile through the limb is presented for the photospheric SrI 460.7 nm line, the low chromospheric BaII 455.4 nm line, and the CaI 422.7 nm line within a distance of 120´´, together with measurements of the mean continuum polarization obtained in imagery mode. Preliminary results of the polarization of the SrI 460.7 nm line are also shown at 40´´ from the limb, as a function of the brightness of structures visible in the continuum (granulation). They reveal a tendency for the polarization to be weaker in dark features (intergranules) than in bright ones (granules), suggesting a stronger magnetic field in intergranular lanes. As example the enigmatic and weak polarization signal in the

  3. The impact of orbital sampling, monthly averaging and vertical resolution on climate chemistry model evaluation with satellite observations

    Directory of Open Access Journals (Sweden)

    A. M. Aghedo

    2011-07-01

    troposphere, respectively. Up to 8 % bias was calculated in the upper troposphere water vapour due to monthly-mean operators, which may impact the detection of water vapour feedback in response to global warming. Our results reveal the importance of using the averaging kernel and the a priori profiles to account for the limited vertical resolution and clouds of a nadir observation during model application. Neglecting the observation operators resulted in large biases, which are more than 60 % for ozone, ±30 % for carbon monoxide, and range between −1.5 K and 5 K for atmospheric temperature, and between −60 % and 100 % for water vapour.

  4. The impact of orbital sampling, monthly averaging and vertical resolution on climate chemistry model evaluation with satellite observations

    Directory of Open Access Journals (Sweden)

    A. M. Aghedo

    2011-03-01

    troposphere water vapour due to monthly-mean operators, which may impact the detection of water vapour feedback in response to global warming. Our results reveal the importance of using the averaging kernel and the a priori profiles to account for the limited vertical resolution of a nadir observation during model application. Neglecting the observation operators resulted in large biases, which are more than 60% for ozone, ±30% for carbon monoxide, and range between −1.5 K and 5 K for atmospheric temperature, and between −60% and 100% for water vapour.

  5. LAMOST Observations in the Kepler Field. Analysis of the Stellar Parameters Measured with LASP Based on Low-resolution Spectra

    Science.gov (United States)

    Ren, Anbing; Fu, Jianning; De Cat, Peter; Wu, Yue; Yang, Xiaohu; Shi, Jianrong; Luo, Ali; Zhang, Haotong; Dong, Subo; Zhang, Ruyuan; Zhang, Yong; Hou, Yonghui; Wang, Yuefei; Cao, Zihuang; Du, Bing

    2016-08-01

    All 14 subfields of the Kepler field were observed at least once with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (lamost, Xinglong Observatory, China) during the 2012-2014 observation seasons. There are 88,628 reduced spectra with a signal-to-noise ratio in the g band (S/N g ) ≥ 6 after the first round (2012-2014) of observations of the lamost- Kepler project (LK-project). By adopting the upgraded version of the lamost Stellar Parameter pipeline (lasp), we have determined the atmospheric parameters ({T}{eff}, {log}g, and [Fe/H]) and heliocentric radial velocity v rad for 51,406 stars with 61,226 spectra. Compared with the atmospheric parameters derived from both high-resolution spectroscopy and asteroseismology for common stars in Huber et al., an external calibration of lasp atmospheric parameters was made, leading to the determination of the external errors for giants and dwarfs. Multiple spectroscopic observations of the same objects in the LK-project were used to estimate the internal uncertainties of the atmospheric parameters as a function of S/N g with the unbiased estimation method. The lasp atmospheric parameters were calibrated based on both the external and internal uncertainties for the giants and dwarfs. A general statistical analysis of the stellar parameters leads to the discovery of 106 candidate metal-poor stars, 9 candidate very metal-poor stars, and 18 candidate high-velocity stars. Fitting formulae were obtained segmentally for both the calibrated atmospheric parameters of the LK-project and the Kepler Input Catalog (KIC) parameters with common stars. The calibrated atmospheric parameters and radial velocities of the LK-project will be useful for studying stars in the Kepler field. ) located at the Xinglong Observatory, China.

  6. Angular integrals in d dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, Gabor

    2011-01-15

    We discuss the evaluation of certain d dimensional angular integrals which arise in perturbative field theory calculations. We find that the angular integral with n denominators can be computed in terms of a certain special function, the so-called H-function of several variables. We also present several illustrative examples of the general result and briefly consider some applications. (orig.)

  7. Intrinsic Angular Momentum of Light.

    Science.gov (United States)

    Santarelli, Vincent

    1979-01-01

    Derives a familiar torque-angular momentum theorem for the electromagnetic field, and includes the intrinsic torques exerted by the fields on the polarized medium. This inclusion leads to the expressions for the intrinsic angular momentum carried by the radiation traveling through a charge-free medium. (Author/MA)

  8. Observation of antisite domain boundaries in Cu2ZnSnS4 by atomic-resolution transmission electron microscopy

    Science.gov (United States)

    Kattan, N. A.; Griffiths, I. J.; Cherns, D.; Fermín, D. J.

    2016-07-01

    Atomic resolution transmission electron microscopy has been used to examine antisite defects in Cu2ZnSnS4 (CZTS) kesterite crystals grown by a hot injection method. High angle annular dark field (HAADF) imaging at sub-0.1 nm resolution, and lower magnification dark field imaging using reflections sensitive to cation ordering, are used to reveal antisite domain boundaries (ADBs). These boundaries, typically 5-20 nm apart, and extending distances of 100 nm or more into the crystals, lie on a variety of planes and have displacements of the type ½[110] or ¼[201], which translate Sn, Cu and Zn cations into antisite positions. It is shown that some ADBs describe a change in the local stoichiometry by removing planes of S and either Cu or Zn atoms, implying that these boundaries can be electrically charged. The observations also showed a marked increase in cation disorder in regions within 1-2 nm of the grain surfaces suggesting that growth of the ordered crystal takes place at the interface with a disordered shell. It is estimated that the ADBs contribute on average ~0.1 antisite defect pairs per unit cell. Although this is up to an order of magnitude less than the highest antisite defect densities reported, the presence of high densities of ADBs that may be charged suggests these defects may have a significant influence on the efficiency of CZTS solar cells.Atomic resolution transmission electron microscopy has been used to examine antisite defects in Cu2ZnSnS4 (CZTS) kesterite crystals grown by a hot injection method. High angle annular dark field (HAADF) imaging at sub-0.1 nm resolution, and lower magnification dark field imaging using reflections sensitive to cation ordering, are used to reveal antisite domain boundaries (ADBs). These boundaries, typically 5-20 nm apart, and extending distances of 100 nm or more into the crystals, lie on a variety of planes and have displacements of the type ½[110] or ¼[201], which translate Sn, Cu and Zn cations into antisite

  9. High-resolution CO observation of the carbon star CIT 6 revealing the spiral structure and a nascent bipolar outflow

    CERN Document Server

    Kim, Hyosun; Hirano, Naomi; Zhao-Geisler, Ronny; Trejo, Alfonso; Yen, Hsi-Wei; Taam, Ronald E; Kemper, Francisca; Kim, Jongsoo; Byun, Do-Young; Liu, Tie

    2015-01-01

    CIT 6 is a carbon star in the transitional phase from the asymptotic giant branch (AGB) to the protoplanetary nebulae (pPN). Observational evidences of two point sources in the optical, circumstellar arc segments in an HC$_3$N line emission, and a bipolar nebula in near-infrared provide strong support for the presence of a binary companion. Hence, CIT 6 is very attractive for studying the role of companions in the AGB-pPN transition. We have carried out high resolution $^{12}$CO $J=2-1$ and $^{13}$CO $J=2-1$ observations of CIT 6 with the Submillimeter Array combined with the Submillimeter Telescope (single-dish) data. The $^{12}$CO channel maps reveal a spiral-shell pattern connecting the HC$_3$N segments in a continuous form, and an asymmetric outflow corresponding to the near-infrared bipolar nebula. Rotation of the $^{12}$CO channel peak position may be related to the inner spiral winding and/or the bipolar outflow. An eccentric orbit binary is suggested for the presences of an anisotropic mass loss to th...

  10. High-spectral resolution observations of the 3.29 micron emission feature: Comparison to QCC and PAHs

    Science.gov (United States)

    Tokunaga, Alan T.; Sellgren, Kris; Sakata, Akira; Wada, S.; Onaka, Takashi; Nakada, Y.; Nagata, T.

    1989-01-01

    Two of the most promising explanations for the origin of the interstellar emission features observed at 3.29, 3.4, 6.2, 7.7, 8.6, and 11.3 microns are: quenched carbonaceous composite (QCC) and polycyclic aromatic hydrocarbons (PAHs). High resolution spectra are given of the 3.29 micron emission feature which were taken with the Cooled Grating Array Spectrometer at the NASA Infrared Telescope Facility and previously published. These spectra show that the peak wavelength of the 3.29 micron feature is located at 3.295 + or - 0.005 micron and that it is coincident with the peak absorbance of QCC. The peak wavelength of the 3.29 micron feature appears to be the same in all of the sources observed thus far. However, the width of the feature in HD 44179 and Elias 1 is only 0.023 micron, which is smaller than the 0.043 micron width in NGC 7027, IRAS 21282+5050, the Orion nebula, and BD+30 deg 3639. Spectra of NGC 7027, QCC, and PAHs is shown. QCC matches the 3.29 micron interstellar emission feature very closely in the wavelength of the peak, and it produces a single feature. On the other hand, PAHs rarely match the peak of the interstellar emission feature, and characteristically produce multiple features.

  11. Tracking Jupiter's Quasi-Quadrennial Oscillation and Mid-Latitude Zonal Waves with High Spectral Resolution Mid-Infrared Observations

    Science.gov (United States)

    Greathouse, Thomas K.; Orton, Glenn S.; Cosentino, Rick; Morales-Juberias, Raul; Fletcher, Leigh N.; Giles, Rohini Sara; Melin, Henrik; Encrenaz, Therese A.; Fouchet, Thierry; DeWitt, Curtis N.

    2016-10-01

    We report on early results of a long term observational study to track the temporal and 3-dimensional evolution of the Quasi-Quadrennial Oscillation (QQO) and the propagation and evolution of mid-latitude zonal waves in Jupiter's stratosphere. These wave-driven phenomena affect variations in Jupiter's vertical and horizontal temperature field, which can be inferred by measuring methane emission in the thermal infrared near 1245 cm-1. Using TEXES, the Texas Echelon cross-dispersed Echelle Spectrograph, mounted on the NASA Infrared Telescope Facility (IRTF) we observed high-spectral resolution (R=75,000) scan maps of Jupiter's equator to mid-latitudes from January 2012 through to the present. We will present the zonally averaged inferred thermal structure within ±30° latitude of the equator and between 10 and 0.01 mbar, showing the QQO's downward progression along with inferred 3-dimensional thermal maps (latitude, longitude, pressure) displaying a multitude of independent waves and eddies at various latitudes and pressures. These results reveal a vast array of wave activity on Jupiter and will serve to: 1) significantly improve the determination of the period and vertical descent velocity of Jupiter's QQO; 2) measure the zonal wavenumbers, vertical wavelengths, zonal group velocities and lifetimes of transient mid-latitude waves; and 3) record the thermal state of Jupiter's stratosphere in detail prior to, during, and after Juno's prime mission.

  12. High-resolution VLBA Observations of Three 7 mm SiO Masers toward VX Sgr at Five Epochs

    Science.gov (United States)

    Su, J. B.; Shen, Z.-Q.; Chen, X.; Yi, Jiyune; Jiang, D. R.; Yun, Y. J.

    2012-07-01

    VX Sgr is a red supergiant at an adopted distance of 1.6 kpc with intense 43 GHz SiO maser emission. In this paper, we present the high-resolution very long baseline interferometry (VLBI) observations of SiO masers toward VX Sgr at five epochs. We used the Very Long Baseline Array to map the J = 1→0 (v = 1, 2) 28SiO masers and confirmed a ring-like structure. In the first two epochs, the v = 1 masers form a ring, but v = 2 maser spots residing only in the southern and northern regions do not form a complete ring. In the third epoch, the two masers are distributed in a ring structure and the v = 2 masers are a bit closer to the central star. In the last two epochs, many new maser spots appear and overlap each other. These overlapping maser spots can be related to the shock waves and reflect the collisional pumping. We compare the observations with the pumping models and speculate that the real pumping mechanism may be complex in VX Sgr and vary with time. The J = 1→0 (v = 0) 29SiO line emission is also detected, but is too weak to produce any VLBI map.

  13. High-Resolution NDVI from Planet's Constellation of Earth Observing Nano-Satellites: A New Data Source for Precision Agriculture

    KAUST Repository

    Houborg, Rasmus

    2016-09-19

    Planet Labs ("Planet") operate the largest fleet of active nano-satellites in orbit, offering an unprecedented monitoring capacity of daily and global RGB image capture at 3-5 m resolution. However, limitations in spectral resolution and lack of accurate radiometric sensor calibration impact the utility of this rich information source. In this study, Planet\\'s RGB imagery was translated into a Normalized Difference Vegetation Index (NDVI): a common metric for vegetation growth and condition. Our framework employs a data mining approach to build a set of rule-based regression models that relate RGB data to atmospherically corrected Landsat-8 NDVI. The approach was evaluated over a desert agricultural landscape in Saudi Arabia where the use of near-coincident (within five days) Planet and Landsat-8 acquisitions in the training of the regression models resulted in NDVI predictabilities with an r2 of approximately 0.97 and a Mean Absolute Deviation (MAD) on the order of 0.014 (~9%). The MAD increased to 0.021 (~14%) when the Landsat NDVI training image was further away (i.e., 11-16 days) from the corrected Planet image. In these cases, the use of MODIS observations to inform on the change in NDVI occurring between overpasses was shown to significantly improve prediction accuracies. MAD levels ranged from 0.002 to 0.011 (3.9% to 9.1%) for the best performing 80% of the data. The technique is generic and extendable to any region of interest, increasing the utility of Planet\\'s dense time-series of RGB imagery.

  14. Angular momentum of sound pulses.

    Science.gov (United States)

    Lekner, John

    2006-07-05

    Three-dimensionally localized acoustic pulses in an isotropic fluid medium necessarily have transverse components of momentum density. Those with an azimuthal component of momentum density can carry angular momentum. The component of total pulse angular momentum along the direction of the total momentum is an invariant (constant in time and independent of choice of origin). The pulse energy, momentum and angular momentum are evaluated analytically for a family of localized solutions of the wave equation. In the limit where the pulses have many oscillations within their spatial extent ([Formula: see text], where k is the wavenumber and a determines the size of a pulse), the energy, momentum and angular momentum are consistent with a multiphonon representation of the pulse, each phonon having energy [Formula: see text], momentum [Formula: see text] and angular momentum [Formula: see text] (with integer m).

  15. Fundamental parameters of 16 late-type stars derived from their angular diameter measured with VLTI/AMBER

    CERN Document Server

    Cruzalèbes, P; Rabbia, Y; Sacuto, S; Chiavassa, A; Pasquato, E; Plez, B; Eriksson, K; Spang, A; Chesneau, O

    2013-01-01

    Thanks to their large angular dimension and brightness, red giants and supergiants are privileged targets for optical long-baseline interferometers. Sixteen red giants and supergiants have been observed with the VLTI/AMBER facility over a two-years period, at medium spectral resolution (R=1500) in the K band. The limb-darkened angular diameters are derived from fits of stellar atmospheric models on the visibility and the triple product data. The angular diameters do not show any significant temporal variation, except for one target: TX Psc, which shows a variation of 4% using visibility data. For the eight targets previously measured by Long-Baseline Interferometry (LBI) in the same spectral range, the difference between our diameters and the literature values is less than 5%, except for TX Psc, which shows a difference of 11%. For the 8 other targets, the present angular diameters are the first measured from LBI. Angular diameters are then used to determine several fundamental stellar parameters, and to loca...

  16. 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.

  17. A Study of the Angular Distribution of the Secondary Particles of bar pAg/Br Reactions at 1.4 GeV/c Incident Momentum Observed in Photographic Emulsion

    Science.gov (United States)

    Breivik, F. O.; Jacobsen, T.; Sørensen, S. O.

    1983-09-01

    Some features of bar pAg/Br reactions at 1.4 GeV/c incident momentum are studied by means of the emulsion technique. The distributions of the number of charged particles/event are present. The angular distributions indicate some anisotropic process in the nuclear matter, possibly shock-waves, and some back-to-back emission.

  18. Quantitative Assessment of a Novel Super-Resolution Restoration Technique Using HiRISE with Navcam Images: how much Resolution Enhancement is Possible from Repeat-Pass Observations

    Science.gov (United States)

    Tao, Y.; Muller, J.-P.

    2016-06-01

    Higher spatial resolution imaging data is always desirable to the international community of planetary scientists interested in improving understanding of surface formation processes. We have previously developed a novel Super-resolution restoration (SRR) technique (Tao & Muller, 2016) using Gotcha sub-pixel matching, orthorectification, and segmented 4th order PDE-TV, called GPT SRR, which is able to restore 5 cm-12.5 cm near rover scale images (equivalent to Navcam projected FoV at a range of ≥ 5 m) from multiple 25 cm resolution NASA MRO HiRISE images. The SRR technique has been successfully applied to the rover traverses for the MER and MSL missions within the EU FP-7 PRoViDE project. These SRR results have revealed new surface information including the imaging of individual rocks (diameter ≥ 25 cm) by comparison of the original HiRISE image and rover Navcam orthorectified image mosaics. In this work, we seek evidence from processing a very large number of stereo reconstruction results from all Navcam stereo images within PRoViDE, registration and comparison with the corresponding SRR image, in order to derive a quantitative assessment on key features including rocks (diameter < 150 cm) and rover track wheel spacing. We summarise statistics from SRR-Navcam measurements and demonstrate that our unique SRR datasets will greatly support the geological and morphological analysis and monitoring of Martian surface and can also be applied to landing site selection, in order to avoid unsuitable terrain, for any future lander/rover as well as help to define future rover paths.

  19. Detection of a spinning object using light's orbital angular momentum.

    Science.gov (United States)

    Lavery, Martin P J; Speirits, Fiona C; Barnett, Stephen M; Padgett, Miles J

    2013-08-01

    The linear Doppler shift is widely used to infer the velocity of approaching objects, but this shift does not detect rotation. By analyzing the orbital angular momentum of the light scattered from a spinning object, we observed a frequency shift proportional to product of the rotation frequency of the object and the orbital angular momentum of the light. This rotational frequency shift was still present when the angular momentum vector was parallel to the observation direction. The multiplicative enhancement of the frequency shift may have applications for the remote detection of rotating bodies in both terrestrial and astronomical settings.

  20. Probing seismic solar analogues through observations with the NASA Kepler space telescope and HERMES high-resolution spectrograph

    CERN Document Server

    Beck, P G; García, R A; Nascimento,, J do; Duarte, T S S; Mathis, S; Regulo, C; Ballot, J; Egeland, R; Castro, M; Pérez-Herńandez, F; Creevey, O; Tkachenko, A; van Reeth, T; Bigot, L; Corsaro, E; Metcalfe, T; Mathur, S; Palle, P L; Prieto, C Allende; Montes, D; Johnston, C; Andersen, M F; van Winckel, H

    2016-01-01

    Stars similar to the Sun, known as solar analogues, provide an excellent opportunity to study the preceding and following evolutionary phases of our host star. The unprecedented quality of photometric data collected by the \\Kepler NASA mission allows us to characterise solar-like stars through asteroseismology and study diagnostics of stellar evolution, such as variation of magnetic activity, rotation and the surface lithium abundance. In this project, presented in a series of papers by Salabert et al. (2016a,b) and Beck et al (2016a,b), we investigate the link between stellar activity, rotation, lithium abundance and oscillations in a group of 18 solar-analogue stars through space photometry, obtained with the NASA Kepler space telescope and from currently 50+ hours of ground-based, high-resolution spectroscopy with the Hermes instrument. In these proceedings, we first discuss the selection of the stars in the sample, observations and calibrations and then summarise the main results of the project. By invest...

  1. AngularJS testing cookbook

    CERN Document Server

    Bailey, Simon

    2015-01-01

    This book is intended for developers who have an understanding of the basic principles behind both AngularJS and test-driven development. You, as a developer, are interested in eliminating the fear related to either introducing tests to an existing codebase or starting out testing on a fresh AngularJS application. If you're a team leader or part of a QA team with the responsibility of ensuring full test coverage of an application, then this book is ideal for you to comprehend the full testing scope required by your developers. Whether you're new to or are well versed with AngularJS, this book

  2. HIGH-RESOLUTION CO OBSERVATION OF THE CARBON STAR CIT 6 REVEALING THE SPIRAL STRUCTURE AND A NASCENT BIPOLAR OUTFLOW

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyosun; Liu, Sheng-Yuan; Hirano, Naomi; Zhao-Geisler, Ronny; Trejo, Alfonso; Yen, Hsi-Wei; Taam, Ronald E.; Kemper, Francisca [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Kim, Jongsoo; Byun, Do-Young; Liu, Tie, E-mail: hkim@asiaa.sinica.edu.tw [Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of)

    2015-11-20

    CIT 6 is a carbon star in the transitional phase from the asymptotic giant branch (AGB) to the protoplanetary nebulae (pPNs). Observational evidences of two point sources in the optical, circumstellar arc segments in an HC{sub 3}N line emission, and a bipolar nebula in near-infrared provide strong support for the presence of a binary companion. Hence, CIT 6 is very attractive for studying the role of companions in the AGB–pPN transition. We have carried out high-resolution {sup 12}CO J = 2–1 and {sup 13}CO J = 2–1 observations of CIT 6 with the Submillimeter Array combined with the Submillimeter Telescope (single-dish) data. The {sup 12}CO channel maps reveal a spiral-shell pattern connecting the HC{sub 3}N segments in a continuous form and an asymmetric outflow corresponding to the near-infrared bipolar nebula. Rotation of the {sup 12}CO channel peak position may be related to the inner spiral winding and/or the bipolar outflow. An eccentric orbit binary is suggested for the presence of an anisotropic mass loss to the west and a double spiral pattern. The lack of interarm emission to the west may indicate a feature corresponding to the periastron passage of a highly eccentric orbit of the binary. Spatially averaged radial and spectral profiles of {sup 12}CO J = 2–1 and {sup 13}CO J = 2–1 are compared with simple spherical radiative transfer models, suggesting a change of {sup 12}CO/{sup 13}CO abundance ratio from ∼30 to ∼50 inward in the CSE of CIT 6. The millimeter continuum emission is decomposed into extended dust thermal emission (spectral index ∼ −2.4) and compact emission from radio photosphere (spectral index ∼ −2.0)

  3. Direct Observation of the Outermost Surfaces of Mesoporous Silica Thin Films by High Resolution Ultralow Voltage Scanning Electron Microscopy.

    Science.gov (United States)

    Kobayashi, Maho; Susuki, Kyoka; Otsuji, Haruo; Sakuda, Yusuke; Asahina, Shunsuke; Kikuchi, Naoki; Kanazawa, Toshiyuki; Kuroda, Yoshiyuki; Wada, Hiroaki; Shimojima, Atsushi; Kuroda, Kazuyuki

    2017-02-20

    The properties of the outermost surfaces of mesoporous silica thin films are critical in determining their functions. Obtaining information on the presence or absence of silica layers on the film surfaces and on the degree of mesopore opening is essential for applications of surface mesopores. In this study, the outermost surfaces of mesoporous silica thin films with 3-dimensional orthorhombic and 2-dimensional hexagonal structures were observed using ultralow voltage high resolution scanning electron microscopy (HR-SEM) with decelerating optics. SEM images of the surfaces before and after etching with NH4F were taken at various landing voltages. Comparing the images taken under different conditions indicated that the outermost surfaces of the nonetched mesoporous silica thin films are coated with a thin layer of silica. The images taken at an ultralow landing voltage (i.e., 80 V) showed that the presence or absence of surface silica layers depends on whether the film was etched with an aqueous solution of NH4F. The mesostructures of both the etched and nonetched films were visible in images taken at a conventional landing voltage (2 kV); hence, the ultralow landing voltage was more suitable for analyzing the outermost surfaces. The SEM observations provided detailed information about the surfaces of mesoporous silica thin films, such as the degree of pore opening and their homogeneities. AFM images of nonetched 2-dimensional hexagonal mesoporous silica thin films show that the shape of the silica layer on the surface of the films reflects the curvature of the top surface of the cylindrical mesochannels. SEM images taken at various landing voltages are discussed, with respect to the electron penetration range at each voltage. This study increases our understanding of the surfaces of mesoporous silica thin films, which may lead to potential applications utilizing the periodically arranged mesopores on these surfaces.

  4. The Jets of TeV Blazars at Higher Resolution: 43 GHz and Polarimetric VLBA Observations from 2005 to 2009

    Science.gov (United States)

    Piner, B. Glenn; Pant, Niraj; Edwards, Philip G.

    2010-11-01

    We present 23 new VLBA images of the six established TeV blazars Markarian 421, Markarian 501, H 1426+428, 1ES 1959+650, PKS 2155-304, and 1ES 2344+514, obtained from 2005 to 2009. Most images were obtained at 43 GHz (7 mm), and they reveal the parsec-scale structures of three of these sources (1ES 1959+650, PKS 2155-304, and 1ES 2344+514) at factors of 2-3 higher resolution than has previously been attained. These images reveal new morphological details, including a high degree of jet bending in the inner milliarcsecond in PKS 2155-304. This establishes strong apparent jet bending on VLBI scales as a common property of TeV blazars, implying viewing angles close to the line of sight. Most of the remaining images map the linear polarization structures at a lower frequency of 22 GHz (1 cm). We discuss the transverse structures of the jets as revealed by the high-frequency and polarimetric imaging. The transverse structures include significant limb brightening in Mrk 421, and "spine-sheath" structures in the electric vector position angle and fractional polarization distributions in Mrk 421, Mrk 501, and 1ES 1959+650. We use new measured component positions to update measured apparent jet speeds, in many cases significantly reducing the statistical error over previously published results. With the increased resolution at 43 GHz, we detect new components within 0.1-0.2 mas of the core in most of these sources. No motion is apparent in these new components over the time span of our observations, and we place upper limits on the apparent speeds of the components near the core of <2c. From those limits, we conclude that Γ2 < (Γ1)1/2 at ~105 Schwarzschild radii, where Γ1 and Γ2 are the bulk Lorentz factors in the TeV emitting and 43 GHz emitting regions, respectively, assuming that their velocity vectors are aligned.

  5. Radio & Optical Interferometry: Basic Observing Techniques and Data Analysis

    CERN Document Server

    Monnier, John D

    2012-01-01

    Astronomers usually need the highest angular resolution possible, but the blurring effect of diffraction imposes a fundamental limit on the image quality from any single telescope. Interferometry allows light collected at widely-separated telescopes to be combined in order to synthesize an aperture much larger than an individual telescope thereby improving angular resolution by orders of magnitude. Radio and millimeter wave astronomers depend on interferometry to achieve image quality on par with conventional visible and infrared telescopes. Interferometers at visible and infrared wavelengths extend angular resolution below the milli-arcsecond level to open up unique research areas in imaging stellar surfaces and circumstellar environments. In this chapter the basic principles of interferometry are reviewed with an emphasis on the common features for radio and optical observing. While many techniques are common to interferometers of all wavelengths, crucial differences are identified that will help new practi...

  6. Coherent Control of Photoelectron Wavepacket Angular Interferograms

    OpenAIRE

    Hockett, Paul; Wollenhaupt, Matthias; Baumert, Thomas

    2015-01-01

    Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the cohere...

  7. Improved SOT (Hinode mission) high resolution solar imaging observations: 2—Photometric properties of sunspot umbral dots

    Science.gov (United States)

    Goodarzi, H.; Koutchmy, S.; Adjabshirizadeh, A.

    2016-11-01

    The origin and evolution of solar sunspots in deep photospheric layers are not yet well understood. The case of a quasi-symmetric single mature sunspot near the solar centre is selected for analysis. We use the best available observations of the partial Sun free of turbulent Earth atmospheric effects from the Solar Optical Telescope (SOT) onboard the Hinode spacecraft, after greatly improving the resolution with an optimum Max-likelihood deconvolution with the Point Spread Function (PSF) deduced in a preceding paper. For several different images both the smearing due to the instrumental diffraction effects (PSF core) and the large angle stray light are removed. The selected iterative processing depends on both the signal/noise ratio and on the desired contrast of the ultimate details under examination. The photometric properties of bright umbral dots (BUDs) are deduced from corrected frames. Calibrated isophote maps are provided to show the intensity variations around each UD across the background umbra and the surrounding photospheric field, including the penumbra. We deduce the typical photometrical properties of bright UDs that populate the whole umbral surface down to sub-pixel scales of 0.05448''. The analysis demonstrates the basic heterogeneous nature of the umbra, similar to a network of minute bright and dark round or elongated cells with a spacing of order of 0.35''. For the first time a complete and detailed map of the color index and temperature deduced from the analysis of deeply corrected continuum images is provided, showing that tiny bright UDs can reach photospheric temperatures and even higher for the peripheral BUDs. In the umbra, there are some very dark small regions with temperatures as low as 3100 K. Close links seemingly exist with bright UDs. Central BUDs and peripheral BUDs are found to have similar properties but significantly different contrast values. Photometric analysis shows a large dispersion that reflects the broad range of

  8. Evaluation of applicability of high-resolution multiangle imaging photo-polarimetric observations for aerosol atmospheric correction

    Science.gov (United States)

    Kalashnikova, Olga; Garay, Michael; Xu, Feng; Diner, David; Seidel, Felix

    2016-07-01

    Multiangle spectro-polarimetric measurements have been advocated as an additional tool for better understanding and quantifying the aerosol properties needed for atmospheric correction for ocean color retrievals. The central concern of this work is the assessment of the effects of absorbing aerosol properties on remote sensing reflectance measurement uncertainty caused by neglecting UV-enhanced absorption of carbonaceous particles and by not accounting for dust nonsphericity. In addition, we evaluate the polarimetric sensitivity of absorbing aerosol properties in light of measurement uncertainties achievable for the next generation of multi-angle polarimetric imaging instruments, and demonstrate advantages and disadvantages of wavelength selection in the UV/VNIR range. In this work a vector Markov Chain radiative transfer code including bio-optical models was used to quantitatively evaluate in water leaving radiances between atmospheres containing realistic UV-enhanced and non-spherical aerosols and the SEADAS carbonaceous and dust-like aerosol models. The phase matrices for the spherical smoke particles were calculated using a standard Mie code, while those for non-spherical dust particles were calculated using the numerical approach developed for modeling dust for the AERONET network of ground-based sunphotometers. As a next step, we have developed a retrieval code that employs a coupled Markov Chain (MC) and adding/doubling radiative transfer method for joint retrieval of aerosol properties and water leaving radiance from Airborne Multiangle SpectroPolarimetric Imager-1 (AirMSPI-1) polarimetric observations. The AirMSPI-1 instrument has been flying aboard the NASA ER-2 high altitude aircraft since October 2010. AirMSPI typically acquires observations of a target area at 9 view angles between ±67° at 10 m resolution. AirMSPI spectral channels are centered at 355, 380, 445, 470, 555, 660, and 865 nm, with 470, 660, and 865 reporting linear polarization. We

  9. High-resolution Imaging of Transiting Extrasolar Planetary systems (HITEP). I. Lucky imaging observations of 101 systems in the southern hemisphere

    CERN Document Server

    Evans, D F; Maxted, P F L; Skottfelt, J; Hundertmark, M; Jørgensen, U G; Dominik, M; Alsubai, K A; Andersen, M I; Bozza, V; Bramich, D M; Burgdorf, M J; Ciceri, S; D'Ago, G; Jaimes, R Figuera; Gu, S H; Haugbølle, T; Hinse, T C; Juncher, D; Kains, N; Kerins, E; Korhonen, H; Kuffmeier, M; Peixinho, N; Popovas, A; Rabus, M; Rahvar, S; Schmidt, R W; Snodgrass, C; Starkey, D; Surdej, J; Tronsgaard, R; von Essen, C; Wang, Yi-Bo; Wertz, O

    2016-01-01

    (abridged) Context. Wide binaries are a potential pathway for the formation of hot Jupiters. The binary fraction among host stars is an important discriminator between competing formation theories, but has not been well characterised. Additionally, contaminating light from unresolved stars can significantly affect the accuracy of photometric and spectroscopic measurements in studies of transiting exoplanets. Aims. We observed 101 transiting exoplanet host systems in the Southern hemisphere in order to create a homogeneous catalogue of both bound companion stars and contaminating background stars. We investigate the binary fraction among the host stars in order to test theories for the formation of hot Jupiters, in an area of the sky where transiting exoplanetary systems have not been systematically searched for stellar companions. Methods. Lucky imaging observations from the Two Colour Instrument on the Danish 1.54m telescope at La Silla were used to search for previously unresolved stars at small angular sep...

  10. Probing Seismic Solar Analogues Through Observations With The NASA Kepler Space Telescope and Hermes High-Resolution Spectrograph

    Science.gov (United States)

    Beck, P. G.; Salabert, D.; Garcia, R. A.; do Nascimento, J., Jr.; Duarte, T. S. S.; Mathis, S.; Regulo, C.; Ballot, J.; Egeland, R.; Castro, M.; Pérez-Herńandez, F.,; Creevey, O.; Tkachenko, A.; van Reeth, T.; Bigot, L.; Corsaro, E.; Metcalfe, T.; Mathur, S.; Palle, P. L.; Allende Prieto, C.; Montes, D.; Johnston, C.; Andersen, M. F.; van Winckel, H.

    2016-11-01

    Stars similar to the Sun, known as solar analogues, provide an excellent opportunity to study the preceding and following evolutionary phases of our host star. The unprecedented quality of photometric data collected by the Kepler NASA mission allows us to characterise solar-like stars through asteroseismology and study diagnostics of stellar evolution, such as variation of magnetic activity, rotation and the surface lithium abundance. In this project, presented in a series of papers by Salabert et al (2016ab) and Beck et al. (2016ab), we investigate the link between stellar activity, rotation, lithium abundance and oscillations in a group of 18 solar-analogue stars through space photometry, obtained with the NASA Kepler space telescope and from currently 50+ hours of ground-based, high-resolution spectroscopy with the Hermes instrument. In these proceedings, we first discuss the selection of the stars in the sample, observations and calibrations and then summarise the main results of the project. By investigating the chromospheric and photospheric activity of the solar analogues in this sample, it was shown that for a large fraction of these stars the measured activity levels are compatible to levels of the 11-year solar activity cycle 23. A clear correlation between the lithium abundance and surface rotation was found for rotation periods shorter than the solar value. Comparing the lithium abundance measured in the solar analogues to evolutionary models with the Toulouse-Geneva Evolutionary Code (TGEC), we found that the solar models calibrated to the Sun also correctly describe the set of solar/stellar analogs showing that they share the same internal mixing physics. Finally, the star KIC3241581 and KIC10644353 are discussed in more detail.

  11. High spatio-temporal resolution observations of crater lake temperatures at Kawah Ijen volcano, East Java, Indonesia

    Science.gov (United States)

    Lewicki, Jennifer L.; Caudron, Corentin; van Hinsberg, Vincent J.; Hilley, George E.

    2016-08-01

    The crater lake of Kawah Ijen volcano, East Java, Indonesia, has displayed large and rapid changes in temperature at point locations during periods of unrest, but measurement techniques employed to date have not resolved how the lake's thermal regime has evolved over both space and time. We applied a novel approach for mapping and monitoring variations in crater lake apparent surface ("skin") temperatures at high spatial (˜32 cm) and temporal (every 2 min) resolution at Kawah Ijen on 18 September 2014. We used a ground-based FLIR T650sc camera with digital and thermal infrared (TIR) sensors from the crater rim to collect (1) a set of visible imagery around the crater during the daytime and (2) a time series of co-located visible and TIR imagery at one location from pre-dawn to daytime. We processed daytime visible imagery with the Structure-from-Motion photogrammetric method to create a digital elevation model onto which the time series of TIR imagery was orthorectified and georeferenced. Lake apparent skin temperatures typically ranged from ˜21 to 33 °C. At two locations, apparent skin temperatures were ˜4 and 7 °C less than in situ lake temperature measurements at 1.5 and 5-m depth, respectively. These differences, as well as the large spatio-temporal variations observed in skin temperatures, were likely largely associated with atmospheric effects such as the evaporative cooling of the lake surface and infrared absorption by water vapor and SO2. Calculations based on orthorectified TIR imagery thus yielded underestimates of volcanic heat fluxes into the lake, whereas volcanic heat fluxes estimated based on in situ temperature measurements (68 to 111 MW) were likely more representative of Kawah Ijen in a quiescent state. The ground-based imaging technique should provide a valuable tool to continuously monitor crater lake temperatures and contribute insight into the spatio-temporal evolution of these temperatures associated with volcanic activity.

  12. Searching for fast optical transients by means of a wide-field monitoring observations with high temporal resolution

    Science.gov (United States)

    Beskin, G.; Karpov, S.; Plokhotnichenko, V.; Bondar, S.; Ivanov, E.; Perkov, A.; Greco, G.; Guarnieri, A.; Bartolini, C.

    We discuss the strategy of search for fast optical transients accompanying gamma-ray bursts by means of continuous monitoring of wide sky fields with high temporal resolution. We describe the design, performance and results of our cameras, FAVOR and TORTORA. Also we discuss the perspectives of this strategy and possible design of next-generation equipment for wide-field monitoring which will be able to detect optical transients and to study their color and polarization properties with high time resolution.

  13. Optical imaging and high spatial resolution 21 cm H I observations of the peculiar galaxy NGC 2782 (Arp 215)

    Science.gov (United States)

    Smith, Beverly J.

    1994-01-01

    We have used the Very Large Array (VLA) B and C Arrays to make 21 cm H I observations of the peculiar galaxy NGC 2782 (Arp 215). These observations are complementary to previously published D Array VLA data, which revealed the presence of a long (5 min to 54 kpc) H I plume near the western side of this galaxy. We have also obtained BVRI H alpha images of the main body of this galaxy using the McDonald Observatory 30 inch telescope. The optical images of this galaxy show a strong stellar tail extending to the east, opposite the H I plume. Within the disk of NGC 2782, unsharp masking of the optical images at all 4 broadband wavelengths reveals three bright 'ripples', separated by approximately 15 sec. The light profiles across these ripples are symmetric, without a sharp outer edge. H alpha is strong at the starburst nucleus and along the northern and western sections of the inner ripple. The new higher resolution H I data show that the atomic gas is very clumpy. We have identified ten H I clumps in the long western plume, with H I masses of approximately 10(exp 8) solar mass, similar to those of dwarf galaxies, and column densities of approximately 10(exp 21) cm(exp -2) over surface areas of approximately 10 kpc(exp 2). No CO (1-0) emission has been detected from this plume, suggesting that it is material stripped from the outer edge of a disk galaxy. The H alpha peaks, in contrast, are generally not coincident with H I peaks. No H I is seen at the tip of the eastern extension. The H I distribution near this structure is ring-like rather than tail-like as in the optical data. We have detected redshifted H I absorption toward the central continuum source, indicating gas infall into the nuclear region. Using a restricted 3-body dynamical model, we have successfully reproduced the basic properties of NGC 2782 with an off-center collision between two galaxies, where a lower mass disk companion (M(sub 2)/M(sub 1) approximately 0.25) collides almost head-on with a larger

  14. THE 2014 MARCH 29 X-FLARE: SUBARCSECOND RESOLUTION OBSERVATIONS OF Fe XXI λ1354.1

    Energy Technology Data Exchange (ETDEWEB)

    Young, Peter R. [College of Science, George Mason University, Fairfax, VA 22030 (United States); Tian, Hui [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Jaeggli, Sarah [Department of Physics, Montana State University, P.O. Box 173840, Bozeman, MT 59717 (United States)

    2015-02-01

    The Interface Region Imaging Spectrometer (IRIS) is the first solar instrument to observe ∼10 MK plasma at subarcsecond spatial resolution through imaging spectroscopy of the Fe XXI λ1354.1 forbidden line. IRIS observations of the X1 class flare that occurred on 2014 March 29 at 17:48 UT reveal Fe XXI emission from both the flare ribbons and the post-flare loop arcade. Fe XXI appears at all of the chromospheric ribbon sites, although typically with a delay of one raster (75 s) and sometimes offset by up to 1''. 100-200 km s{sup –1} blue-shifts are found at the brightest ribbons, suggesting hot plasma upflow into the corona. The Fe XXI ribbon emission is compact with a spatial extent of <2'', and can extend beyond the chromospheric ribbon locations. Examples are found of both decreasing and increasing blue-shift in the direction away from the ribbon locations, and blue-shifts were present for at least six minutes after the flare peak. The post-flare loop arcade, seen in Atmospheric Imaging Assembly 131 Å filtergram images that are dominated by Fe XXI, exhibited bright loop-tops with an asymmetric intensity distribution. The sizes of the loop-tops are resolved by IRIS at ≥1'', and line widths in the loop-tops are not broader than in the loop-legs suggesting the loop-tops are not sites of enhanced turbulence. Line-of-sight speeds in the loop arcade are typically <10 km s{sup –1}, and mean non-thermal motions fall from 43 km s{sup –1} at the flare peak to 26 km s{sup –1} six minutes later. If the average velocity in the loop arcade is assumed to be at rest, then it implies a new reference wavelength for the Fe XXI line of 1354.106 ± 0.023 Å.

  15. Simulation of Space-borne Radar Observation from High Resolution Cloud Model - for GPM Dual frequency Precipitation Radar -

    Science.gov (United States)

    Kim, H.; Meneghini, R.; Jones, J.; Liao, L.

    2011-12-01

    A comprehensive space-borne radar simulator has been developed to support active microwave sensor satellite missions. The two major objectives of this study are: 1) to develop a radar simulator optimized for the Dual-frequency Precipitation Radar (KuPR and KaPR) on the Global Precipitation Measurement Mission satellite (GPM-DPR) and 2) to generate the synthetic test datasets for DPR algorithm development. This simulator consists of two modules: a DPR scanning configuration module and a forward module that generates atmospheric and surface radar observations. To generate realistic DPR test data, the scanning configuration module specifies the technical characteristics of DPR sensor and emulates the scanning geometry of the DPR with a inner swath of about 120 km, which contains matched-beam data from both frequencies, and an outer swath from 120 to 245 km over which only Ku-band data will be acquired. The second module is a forward model used to compute radar observables (reflectivity, attenuation and polarimetric variables) from input model variables including temperature, pressure and water content (rain water, cloud water, cloud ice, snow, graupel and water vapor) over the radar resolution volume. Presently, the input data to the simulator come from the Goddard Cumulus Ensemble (GCE) and Weather Research and Forecast (WRF) models where a constant mass density is assumed for each species with a particle size distribution given by an exponential distribution with fixed intercept parameter (N0) and a slope parameter (Λ) determined from the equivalent water content. Although the model data do not presently contain mixed phase hydrometeors, the Yokoyama-Tanaka melting model is used along with the Bruggeman effective dielectric constant to replace rain and snow particles, where both are present, with mixed phase particles while preserving the snow/water fraction. For testing one of the DPR retrieval algorithms, the Surface Reference Technique (SRT), the simulator uses

  16. Mass and Angular Momentum in General Relativity

    CERN Document Server

    Jaramillo, J L

    2010-01-01

    We present an introduction to mass and angular momentum in General Relativity. After briefly reviewing energy-momentum for matter fields, first in the flat Minkowski case (Special Relativity) and then in curved spacetimes with or without symmetries, we focus on the discussion of energy-momentum for the gravitational field. We illustrate the difficulties rooted in the Equivalence Principle for defining a local energy-momentum density for the gravitational field. This leads to the understanding of gravitational energy-momentum and angular momentum as non-local observables that make sense, at best, for extended domains of spacetime. After introducing Komar quantities associated with spacetime symmetries, it is shown how total energy-momentum can be unambiguously defined for isolated systems, providing fundamental tests for the internal consistency of General Relativity as well as setting the conceptual basis for the understanding of energy loss by gravitational radiation. Finally, several attempts to formulate q...

  17. Angular momentum in cluster Spherical Collapse Model

    CERN Document Server

    Cupani, Guido; Mardirossian, Fabio

    2011-01-01

    Our new formulation of the Spherical Collapse Model (SCM-L) takes into account the presence of angular momentum associated with the motion of galaxy groups infalling towards the centre of galaxy clusters. The angular momentum is responsible for an additional term in the dynamical equation which is useful to describe the evolution of the clusters in the non-equilibrium region which is investigated in the present paper. Our SCM-L can be used to predict the profiles of several strategic dynamical quantities as the radial and tangential velocities of member galaxies, and the total cluster mass. A good understanding of the non-equilibrium region is important since it is the natural scenario where to study the infall in galaxy clusters and the accretion phenomena present in these objects. Our results corroborate previous estimates and are in very good agreement with the analysis of recent observations and of simulated clusters.

  18. CMB Anisotropies Total Angular Momentum Method

    CERN Document Server

    Hu, W; Hu, Wayne; White, Martin

    1997-01-01

    A total angular momentum representation simplifies the radiation transport problem for temperature and polarization anisotropy in the CMB. Scattering terms couple only the quadrupole moments of the distributions and each moment corresponds directly to the observable angular pattern on the sky. We develop and employ these techniques to study the general properties of anisotropy generation from scalar, vector and tensor perturbations to the metric and the matter, both in the cosmological fluids and from any seed perturbations (e.g.~defects) that may be present. The simpler, more transparent form and derivation of the Boltzmann equations brings out the geometric and model-independent aspects of temperature and polarization anisotropy formation. Large angle scalar polarization provides a robust means to distinguish between isocurvature and adiabatic models for structure formation in principle. Vector modes have the unique property that the CMB polarization is dominated by magnetic type parity at small angles and ...

  19. Quantum Entanglement of Very High Angular Momenta

    CERN Document Server

    Fickler, Robert; Plick, William N; Krenn, Mario; Schaeff, Christoph; Ramelow, Sven; Zeilinger, Anton

    2012-01-01

    Single photons with helical phase structure may carry a quantized amount of orbital angular momentum (OAM) and are of great interest in quantum information science and fundamental tests of quantum theory. Since there is no theoretical upper limit on how many quanta of OAM a single photon can carry, those systems offer the possibility to create superpositions for one particle and entanglement between two particles with an arbitrary high difference in the quantum number. By transferring polarization entanglement to the OAM degree-of-freedom with an interferometric scheme, we created and observed entanglement up to $600\\bar{h}$ difference in the orbital angular momentum. To our knowledge, we have thus demonstrated entanglement of the highest quantum number in any experiment so far. The only restrictive factor towards even higher numbers arises due to current technical limitations. Furthermore, we show experimentally that the entanglement of very high OAM can be used to improve applications, like the sensitivity ...

  20. Intelligent Cognitive Radio Models for Enhancing Future Radio Astronomy Observations

    Directory of Open Access Journals (Sweden)

    Ayodele Abiola Periola

    2016-01-01

    Full Text Available Radio astronomy organisations desire to optimise the terrestrial radio astronomy observations by mitigating against interference and enhancing angular resolution. Ground telescopes (GTs experience interference from intersatellite links (ISLs. Astronomy source radio signals received by GTs are analysed at the high performance computing (HPC infrastructure. Furthermore, observation limitation conditions prevent GTs from conducting radio astronomy observations all the time, thereby causing low HPC utilisation. This paper proposes mechanisms that protect GTs from ISL interference without permanent prevention of ISL data transmission and enhance angular resolution. The ISL transmits data by taking advantage of similarities in the sequence of observed astronomy sources to increase ISL connection duration. In addition, the paper proposes a mechanism that enhances angular resolution by using reconfigurable earth stations. Furthermore, the paper presents the opportunistic computing scheme (OCS to enhance HPC utilisation. OCS enables the underutilised HPC to be used to train learning algorithms of a cognitive base station. The performances of the three mechanisms are evaluated. Simulations show that the proposed mechanisms protect GTs from ISL interference, enhance angular resolution, and improve HPC utilisation.

  1. Evaluating the potential use of a high-resolution X-band polarimetric radar observations in Urban Hydrology

    Science.gov (United States)

    Anagnostou, Marios N.; Kalogiros, John; Marzano, Frank S.; Anagnostou, Emmanouil N.; Baldini, Luca; Nikolopoulos, EfThymios; Montopoli, Mario; Picciotti, Errico

    2014-05-01

    operational, low-frequency (C-band or S-ban) and high-power weather radars. The above hypothesis is examined using data collected during the HyMEX 2012 Special Observation Period (Nov-Feb) the urban and sub-urban complex terrain area in the Central Italy (CI). The area is densely populated and it includes the high-density populated urban and industrial area of Rome. The orography of CI is quite complex, going from sea level to nearly 3000 m in less than 150 km. The CI area involves many rivers, including two major basins: the Aniene-Tiber basin (1000 km long) and the Aterno-Pescara basin (300 km long), respectively on the west and on the east side of the Apennines ridge. Data include observations from i) the National Observatory of Athens' X-band polarimetric weather radar (XPOL), ii) two X-band miniradars (WR25X located in CNR, WR10X located in Rome Sapienza), iii) a dense network of raingauges and disdrometers (i.e. Parsivel type and 2D-video type). In addition, the experimental area is also covered from the nearby the National Research Council (CNR)'s C-band dual-polarization weather radar (Polar55C), which were involved also in the analysis. A number of storm events are selected and compared with the nearby C-band radar to investigate the potential of using high-resolution and microphysically-derived rainfall based on X-band polarimetric radar observations. Events have been discriminated on the basis of rainfall intensity and hydrological response. Results reveal that in contrast with the other two rainfall sources (in situ and C-band radar), X-band radar rainfall estimates offer an improved representation of the local precipitation variability, which turns to have a significant impact in simulating the peak flows associated with these events.

  2. Global significance of a sub-Moho boundary layer (SMBL) deduced from high-resolution seismic observations

    Science.gov (United States)

    Fuchs, K.; Tittgemeyer, M.; Ryberg, T.; Wenzel, F.; Mooney, W.

    2002-01-01

    We infer the fine structure of a sub-Moho boundary layer (SMBL) at the top of the lithospheric mantle from high-resolution seismic observations of Peaceful Nuclear Explosions (PNE) on superlong-range profiles in Russia. Densely recorded seismograms permit recognition of previously unknown features of teleseismic propagation of the well known Pn and Sn phases, such as a band of incoherent, scattered, high-frequency seismic energy, developing consistently from station to station, apparent velocities of sub-Moho material, and high-frequency energy to distances of more than 3000 km with a coda band, incoherent at 10 km spacing and yet consistently observed to the end of the profiles. Estimates of the other key elements of the SMBL were obtained by finite difference calculations of wave propagation in elastic 2D models from a systematic grid search through parameter space. The SMBL consists of randomly distributed, mild velocity fluctuations of 2% or schlieren of high aspect ratios (???40) with long horizontal extent (???20 km) and therefore as thin as 0.5 km only; SMBL thickness is 60-100 km. It is suggested that the SMBL is of global significance as the physical base of the platewide observed high-frequency phases Pn and Sn. It is shown that wave propagation in the SMBL waveguide is insensitive to the background velocity distribution on which its schlieren are superimposed. This explains why the Pn and Sn phases traverse geological provinces of various age, heat flow, crustal thickness, and tectonic regimes. Their propagation appears to be independent of age. temperature, pressure, and stress. Dynamic stretching of mantle material during subduction or flow, possibly combined with chemical differentiation have to be considered as scale-forming processes in the upper mantle. However, it is difficult to distinguish with the present sets of Pn/Sn array data whether (and also where) the boundary layer is a frozen-in feature of paleo-processes or whether it is a response to

  3. Development of emulsion track expansion techniques for optical-microscopy-observation of low-velocity ion tracks with ranges beyond optical resolution limit

    Energy Technology Data Exchange (ETDEWEB)

    Naka, T. [F-lab., Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Natsume, M. [F-lab., Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)], E-mail: natsume@flab.phys.nagoya-u.ac.jp; Niwa, K.; Hoshino, K.; Nakamura, M.; Nakano, T.; Sato, O. [F-lab., Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)

    2007-11-01

    We succeeded to observe tracks of low-velocity Kr ions, having originally ranges below optical resolution, in a fine grain nuclear emulsion with an optical microscope after expanding the emulsion along the incident direction. This opens up the possibility of tracking low-velocity nuclear recoils from massive dark matter particles using optical microscope scanning systems.

  4. Tropical cyclones in a T159 resolution global climate model: comparison with observations and re-analyses

    Science.gov (United States)

    Bengtsson, L.; Hodges, K. I.; Esch, M.

    2007-08-01

    Tropical cyclones have been investigated in a T159 version of the MPI ECHAM5 climate model using a novel technique to diagnose the evolution of the three-dimensional vorticity structure of tropical cyclones, including their full life cycle from weak initial vortices to their possible extra-tropical transition. Results have been compared with re-analyses [the European Centre for Medium-Range Weather Forecasts (ECMWF) 40-yr Re-analysis (ERA40) and Japanese 25 yr re-analysis (JRA25)] and observed tropical storms during the period 1978-1999 for the Northern Hemisphere. There is no indication of any trend in the number or intensity of tropical storms during this period in ECHAM5 or in re-analyses but there are distinct inter-annual variations. The storms simulated by ECHAM5 are realistic both in space and time, but the model and even more so the re-analyses, underestimate the intensities of the most intense storms (in terms of their maximum wind speeds). There is an indication of a response to El Niño-Southern Oscillation (ENSO) with a smaller number of Atlantic storms during El Niño in agreement with previous studies. The global divergence circulation responds to El Niño by setting up a large-scale convergence flow, with the centre over the central Pacific with enhanced subsidence over the tropical Atlantic. At the same time there is an increase in the vertical wind shear in the region of the tropical Atlantic where tropical storms normally develop. There is a good correspondence between the model and ERA40 except that the divergence circulation is somewhat stronger in the model. The model underestimates storms in the Atlantic but tends to overestimate them in the Western Pacific and in the North Indian Ocean. It is suggested that the overestimation of storms in the Pacific by the model is related to an overly strong response to the tropical Pacific sea surface temperature (SST) anomalies. The overestimation in the North Indian Ocean is likely to be due to an over

  5. High spatio-temporal resolution observations of crater-lake temperatures at Kawah Ijen volcano, East Java, Indonesia

    Science.gov (United States)

    Lewicki, Jennifer L.; Corentin Caudron,; Vincent van Hinsberg,; George Hilley,

    2016-01-01

    The crater lake of Kawah Ijen volcano, East Java, Indonesia, has displayed large and rapid changes in temperature at point locations during periods of unrest, but measurement techniques employed to-date have not resolved how the lake’s thermal regime has evolved over both space and time. We applied a novel approach for mapping and monitoring variations in crater-lake apparent surface (“skin”) temperatures at high spatial (~32 cm) and temporal (every two minutes) resolution at Kawah Ijen on 18 September 2014. We used a ground-based FLIR T650sc camera with digital and thermal infrared (TIR) sensors from the crater rim to collect (1) a set of visible imagery around the crater during the daytime and (2) a time series of co-located visible and TIR imagery at one location from pre-dawn to daytime. We processed daytime visible imagery with the Structure-from-Motion photogrammetric method to create a digital elevation model onto which the time series of TIR imagery was orthorectified and georeferenced. Lake apparent skin temperatures typically ranged from ~21 to 33oC. At two locations, apparent skin temperatures were ~ 4 and 7 oC less than in-situ lake temperature measurements at 1.5 and 5 m depth, respectively. These differences, as well as the large spatio-temporal variations observed in skin temperatures, were likely largely associated with atmospheric effects such as evaporative cooling of the lake surface and infrared absorption by water vapor and SO2. Calculations based on orthorectified TIR imagery thus yielded underestimates of volcanic heat fluxes into the lake, whereas volcanic heat fluxes estimated based on in-situ temperature measurements (68 to 111 MW) were likely more representative of Kawah Ijen in a quiescent state. The ground-based imaging technique should provide a valuable tool to continuously monitor crater-lake temperatures and contribute insight into the spatio-temporal evolution of these temperatures associated with volcanic activity.

  6. Spitzer/infrared spectrograph investigation of mipsgal 24 μm compact bubbles: low-resolution observations

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, M. [Département de Physique, École Normale Supérieure de Cachan, 61 Avenue du Président Wilson, F-94235 Cachan (France); Flagey, N. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Noriega-Crespo, A.; Carey, S. J.; Van Dyk, S. D. [Spitzer Science Center, California Institute of Technology, 1200 East California Boulevard, MC 314-6, Pasadena, CA 91125 (United States); Billot, N. [Instituto de Radio Astronomía Milimétrica, Avenida Divina Pastora, 7, Local 20, E-18012 Granada (Spain); Paladini, R., E-mail: mathias.nowak@ens-cachan.fr [NASA Herschel Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2014-12-01

    We present Spitzer/InfraRed Spectrograph (IRS) low-resolution observations of 11 compact circumstellar bubbles from the MIPSGAL 24 μm Galactic plane survey. We find that this set of MIPSGAL bubbles (MBs) is divided into two categories and that this distinction correlates with the morphologies of the MBs in the mid-infrared (IR). The four MBs with central sources in the mid-IR exhibit dust-rich, low-excitation spectra, and their 24 μm emission is accounted for by the dust continuum. The seven MBs without central sources in the mid-IR have spectra dominated by high-excitation gas lines (e.g., [O IV] 26.0 μm, [Ne V] 14.3 and 24.3 μm, and [Ne III] 15.5 μm), and the [O IV] line accounts for 50% to almost 100% of the 24 μm emission in five of them. In the dust-poor MBs, the [Ne V] and [Ne III] line ratios correspond to high-excitation conditions. Based on comparisons with published IRS spectra, we suggest that the dust-poor MBs are highly excited planetary nebulae (PNs) with peculiar white dwarfs (e.g., Wolf-Rayet [WR] and novae) at their centers. The central stars of the four dust-rich MBs are all massive star candidates. Dust temperatures range from 40 to 100 K in the outer shells. We constrain the extinction along the lines of sight from the IRS spectra. We then derive distance, dust masses, and dust production rate estimates for these objects. These estimates are all consistent with the nature of the central stars. We summarize the identifications of MBs made to date and discuss the correlation between their mid-IR morphologies and natures. Candidate Be/B[e]/luminous blue variable and WR stars are mainly 'rings' with mid-IR central sources, whereas PNs are mostly 'disks' without mid-IR central sources. Therefore we expect that most of the 300 remaining unidentified MBs will be classified as PNs.

  7. NUTRITIONAL STATUS ASSOCIATION WITH ANGULAR CHEILITIS IN PRIMARY STUDENT AGE

    OpenAIRE

    Sumintarti, Sumintarti

    2013-01-01

    ABSTRACT Student in primary level school is in fast and active growth. In this growth stage, they have to supplied by high enough nutrition in exact quality and quantity otherwise they will suffer with some oral disease such as angular cheilitis. This study aimed to measured any association of nutritional status and angular cheilitis occurrence in primary student of Lae-Lae II and Pampang elementary state schools. We used observational analytic with purposive sampling method. All student...

  8. Instant AngularJS starter

    CERN Document Server

    Menard, Dan

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. This book is written in an easytoread style, with a strong emphasis on realworld, practical examples. Stepbystep explanations are provided for performing important tasks.This book is for web developers familiar with JavascriptIt doesn't cover the history of AngularJS, and it's not a pitch to convince you that AngularJS is the best framework on the entire web. It's a guide to help you learn everything you need to know about AngularJS in as few pa

  9. Angular momentum in human walking.

    Science.gov (United States)

    Herr, Hugh; Popovic, Marko

    2008-02-01

    Angular momentum is a conserved physical quantity for isolated systems where no external moments act about a body's center of mass (CM). However, in the case of legged locomotion, where the body interacts with the environment (ground reaction forces), there is no a priori reason for this relationship to hold. A key hypothesis in this paper is that angular momentum is highly regulated throughout the walking cycle about all three spatial directions [|Lt| approximately 0], and therefore horizontal ground reaction forces and the center of pressure trajectory can be explained predominantly through an analysis that assumes zero net moment about the body's CM. Using a 16-segment human model and gait data for 10 study participants, we found that calculated zero-moment forces closely match experimental values (Rx2=0.91; Ry2=0.90). Additionally, the centroidal moment pivot (point where a line parallel to the ground reaction force, passing through the CM, intersects the ground) never leaves the ground support base, highlighting how closely the body regulates angular momentum. Principal component analysis was used to examine segmental contributions to whole-body angular momentum. We found that whole-body angular momentum is small, despite substantial segmental momenta, indicating large segment-to-segment cancellations ( approximately 95% medio-lateral, approximately 70% anterior-posterior and approximately 80% vertical). Specifically, we show that adjacent leg-segment momenta are balanced in the medio-lateral direction (left foot momentum cancels right foot momentum, etc.). Further, pelvis and abdomen momenta are balanced by leg, chest and head momenta in the anterior-posterior direction, and leg momentum is balanced by upper-body momentum in the vertical direction. Finally, we discuss the determinants of gait in the context of these segment-to-segment cancellations of angular momentum.

  10. The Cosmology Large Angular Scale Surveyor (CLASS)

    Science.gov (United States)

    Harrington, Kathleen; Marriange, Tobias; Aamir, Ali; Appel, John W.; Bennett, Charles L.; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T.; Colazo, Felipe; Denis, Kevin; Moseley, Samuel H.; Rostem, Karwan; Wollack, Edward

    2016-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from in ation and the optical depth to reionization through a measurement of the polarized cosmic microwave background (CMB) on the largest angular scales. The frequencies of the four CLASS telescopes, one at 38 GHz, two at 93 GHz, and one dichroic system at 145/217 GHz, are chosen to avoid spectral regions of high atmospheric emission and span the minimum of the polarized Galactic foregrounds: synchrotron emission at lower frequencies and dust emission at higher frequencies. Low-noise transition edge sensor detectors and a rapid front-end polarization modulator provide a unique combination of high sensitivity, stability, and control of systematics. The CLASS site, at 5200 m in the Chilean Atacama desert, allows for daily mapping of up to 70% of the sky and enables the characterization of CMB polarization at the largest angular scales. Using this combination of a broad frequency range, large sky coverage, control over systematics, and high sensitivity, CLASS will observe the reionization and recombination peaks of the CMB E- and B-mode power spectra. CLASS will make a cosmic variance limited measurement of the optical depth to reionization and will measure or place upper limits on the tensor-to-scalar ratio, r, down to a level of 0.01 (95% C.L.).

  11. Angular cheilitis: a clinical and microbial study.

    Science.gov (United States)

    Ohman, S C; Dahlén, G; Möller, A; Ohman, A

    1986-04-01

    The purpose of this prospective study was to re-examine the relative importance of various factors in the pathogenesis of angular cheilitis. Sixty-four patients with cheilitis were examined clinically and microbiologically. In addition, a subsample of 23 patients was examined for serum iron and transferrin. The clinical appearance of the lip lesions fell into 4 categories. A ground rhagad at the corner of the mouth involving adjacent skin, was the most frequent type among dentate patients, whereas among denture wearers a deep lesion following the labial marginal sulcus was frequently observed. Dentate patients and denture wearers with cheilitis often had atopic constitution or cutaneous diseases. Pathogenic microorganisms were cultured from the lesions in all 64 patients; Staphylococcus aureus in 40 patients and Candida albicans in 45. The results of this study indicate a correlation between angular cheilitis and pathogenic microorganisms. Furthermore, among dentate patients, a correlation exists between cutaneous discomfort and angular cheilitis. Other etiological factors suggested for this disorder were found to be of subordinate importance.

  12. Non-Colinearity of Angular Velocity and Angular Momentum

    Science.gov (United States)

    Burr, A. F.

    1974-01-01

    Discusses the principles, construction, and operation of an apparatus which serves to demonstrate the non-colinearity of the angular velocity and momentum vectors as well as the inertial tensors. Applications of the apparatus to teaching of advanced undergraduate mechanics courses are recommended. (CC)

  13. Cygnus A: A Long Wavelength Resolution of the Hot Spots

    CERN Document Server

    Lazio, T J W; Kassim, N E; Perley, R A; Erickson, W C; Carilli, C L; Crane, P C

    2006-01-01

    This paper presents observations of Cygnus A at 74 and 327 MHz at angular resolutions of approximately 10" and 3", respectively. These observations are among the highest angular resolutions obtained below 1000 MHz for this object. While the angular resolution at 74 MHz is not sufficient to separate clearly the hot spots from the lobes, guided by 151 and 327 MHz images, we have estimated the 74 MHz emission from the hot spots. We confirm that the emission from both the western and eastern hot spots flattens at low frequencies and that there is a spectral asymmetry between the two. For the eastern hot spot, a low-energy cutoff in the electron energy spectrum appears to explain the flattening, which implies a cutoff Lorentz factor \\gamma_min ~ 300, though we cannot exclude the possibility that there might be a moderate level of free-free absorption. For the western hot spot, the current observations are not sufficient to distinguish between a free-free absorped power-law spectrum and a synchrotron self-absorbed ...

  14. High spectral and spatial resolution observations of the 12.28 micron emission from H2 in the Orion Molecular Cloud

    Science.gov (United States)

    Beck, S. C.; Tokunaga, A. T.; Bloemhof, E. E.; Serabyn, E.; Townes, C. H.; Lacy, J. H.; Smith, H. A.

    1982-01-01

    The pure rotational S(2) line of H2 at 12.28 microns was sought in 44 positions in the Orion Molecular Cloud with 6-arcsec beams and 35 km/s spectral resolution; and it was detected in 27 positions. The lines are approximately symmetric and have full widths at half-maximum ranging from 100 km/s down to the resolution limit. The distribution of intensities and line shapes is largely consistent with that observed in the 2-micron hydrogen transitions; however, unexpectedly complex line profiles and point-to-point variations in line shapes appear, particularly in the region near IRc9.

  15. MISTiC Winds, a Micro-Satellite Constellation Approach to High Resolution Observations of the Atmosphere using Infrared Sounding and 3D Winds Measurements

    Science.gov (United States)

    Maschhoff, K. R.; Polizotti, J. J.; Susskind, J.; Aumann, H. H.

    2015-12-01

    MISTiCTM Winds is an approach to improve short-term weather forecasting based on a miniature high resolution, wide field, thermal emission spectrometry instrument that will provide global tropospheric vertical profiles of atmospheric temperature and humidity at high (3-4 km) horizontal and vertical ( 1 km) spatial resolution. MISTiC's extraordinarily small size, payload mass of less than 15 kg, and minimal cooling requirements can be accommodated aboard a 27U-class CubeSat or an ESPA-Class micro-satellite. Low fabrication and launch costs enable a LEO sun-synchronous sounding constellation that would collectively provide frequent IR vertical profiles and vertically resolved atmospheric motion vector wind observations in the troposphere. These observations are highly complementary to present and emerging environmental observing systems, and would provide a combination of high vertical and horizontal resolution not provided by any other environmental observing system currently in operation. The spectral measurements that would be provided by MISTiC Winds are similar to those of NASA's Atmospheric Infrared Sounder that was built by BAE Systems and operates aboard the AQUA satellite. These new observations, when assimilated into high resolution numerical weather models, would revolutionize short-term and severe weather forecasting, save lives, and support key economic decisions in the energy, air transport, and agriculture arenas-at much lower cost than providing these observations from geostationary orbit. In addition, this observation capability would be a critical tool for the study of transport processes for water vapor, clouds, pollution, and aerosols. Key technical risks are being reduced through laboratory and airborne testing under NASA's Instrument Incubator Program.

  16. Mistic winds, a microsatellite constellation approach to high-resolution observations of the atmosphere using infrared sounding and 3d winds measurements

    Science.gov (United States)

    Maschhoff, K. R.; Polizotti, J. J.; Aumann, H. H.; Susskind, J.

    2016-10-01

    MISTiC Winds is an approach to improve short-term weather forecasting based on a miniature high resolution, wide field, thermal emission spectrometry instrument that will provide global tropospheric vertical profiles of atmospheric temperature and humidity at high (3-4 km) horizontal and vertical ( 1 km) spatial resolution. MISTiC's extraordinarily small size, payload mass of less than 15 kg, and minimal cooling requirements can be accommodated aboard a 27U-class CubeSat or an ESPA-Class micro-satellite. Low fabrication and launch costs enable a LEO sunsynchronous sounding constellation that would collectively provide frequent IR vertical profiles and vertically resolved atmospheric motion vector wind observations in the troposphere. These observations are highly complementary to present and emerging environmental observing systems, and would provide a combination of high vertical and horizontal resolution not provided by any other environmental observing system currently in operation. The spectral measurements that would be provided by MISTiC Winds are similar to those of NASA's AIRS that was built by BAE Systems and operates aboard the AQUA satellite. These new observations, when assimilated into high resolution numerical weather models, would revolutionize short-term and severe weather forecasting, save lives, and support key economic decisions in the energy, air transport, an