WorldWideScience

Sample records for far-infrared spectral energy

  1. What shapes the far-infrared spectral energy distributions of galaxies?

    CERN Document Server

    Safarzadeh, Mohammadtaher; Ferguson, Henry C; Somerville, Rachel S

    2015-01-01

    To explore the connection between the global physical properties of galaxies and their far-infrared (FIR) spectral energy distributions (SEDs), we study the variation in the FIR SEDs of a set of hydrodynamically simulated galaxies that are generated by performing dust radiative transfer in post-processing. Our sample includes both isolated and merging systems at various stages of the merging process and covers infrared (IR) luminosities and dust masses that are representative of both low- and high-redshift galaxies. We study the FIR SEDs using principle component analysis (PCA) and find that 97\\% of the variance in the sample can be explained by two principle components (PCs). The first PC characterizes the wavelength of the peak of the FIR SED, and the second encodes the breadth of the SED. We find that the coefficients of both PCs can be predicted well using a double power law in terms of the IR luminosity and dust mass, which suggests that these two physical properties are the primary determinants of galax...

  2. Mid-to-Far Infrared Spectral Energy Distribution of Galaxies in the Spitzer First Look Survey Field

    Institute of Scientific and Technical Information of China (English)

    Xiao-Qing Wen; Hong Wu; Chen Cao; Xiao-Yang Xia

    2007-01-01

    We made model fitting to the mid-to-far infrared spectral energy distributions (SEDs) for different categories of galaxies in the main extragalactic field of the Spitzer First Look Survey with the aid of spectroscopic information from the Sloan Digital Sky Survey.We find that the mid-to-far infrared SEDs of HII galaxies, mixture type galaxies and LINERs can be well fitted by the one-parameter (α) dust model of Dale et al. plus the 13 Gyr dust-free elliptical galaxy model. The statistics of α values indicates that all these galaxies tend to be quiescent, although the HII galaxies are relatively more active than the LINERs. The midinfrared SEDs of absorption galaxies are well fitted simply by the 13 Gyr dust-free elliptical galaxy template, and the near-to-mid infrared SEDs of QSOs can be represented by AGN NGC 5506.

  3. Far-Infrared double-Fourier interferometers and their spectral sensitivity

    CERN Document Server

    Rizzo, Maxime J; Rinehart, Stephen A; Dhabal, Arnab; Fixsen, Dale J; Juanola-Parramon, Roser; Benford, Dominic J; Leisawitz, David T; Silverberg, Robert F; Veach, Todd J

    2015-01-01

    Double-Fourier interferometry is the most viable path to sub-arcsecond spatial resolution for future astronomical instruments that will observe the universe at far-infrared wavelengths. The double transform spatio-spectral interferometry couples pupil plane beam combination with detector arrays to enable imaging spectroscopy of wide fields, that will be key to accomplishing top-level science goals. The wide field of view and the necessity for these instruments to fly above the opaque atmosphere create unique characteristics and requirements compared to instruments on ground-based telescopes. In this paper, we discuss some characteristics of single-baseline spatio-spectral interferometers. We investigate the impact of intensity and optical path difference noise on the interferogram and the spectral signal-to-noise ratio. We apply our findings to the special case of the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII), a balloon payload that will be a first application of this technique ...

  4. Quasi-optical analysis of a far-infrared spatio-spectral space interferometer concept

    Science.gov (United States)

    Bracken, C.; O'Sullivan, C.; Murphy, J. A.; Donohoe, A.; Savini, G.; Lightfoot, J.; Juanola-Parramon, R.

    2016-07-01

    FISICA (Far-Infrared Space Interferometer Critical Assessment) was a three year study of a far-infrared spatio-spectral double-Fourier interferometer concept. One of the aims of the FISICA study was to set-out a baseline optical design for such a system, and to use a model of the system to simulate realistic telescope beams for use with an end-to-end instrument simulator. This paper describes a two-telescope (and hub) baseline optical design that fulfils the requirements of the FISICA science case, while minimising the optical mass of the system. A number of different modelling techniques were required for the analysis: fast approximate simulation tools such as ray tracing and Gaussian beam methods were employed for initial analysis, with GRASP physical optics used for higher accuracy in the final analysis. Results are shown for the predicted far-field patterns of the telescope primary mirrors under illumination by smooth walled rectangular feed horns. Far-field patterns for both on-axis and off-axis detectors are presented and discussed.

  5. Detection of small surface vessels in near, medium, and far infrared spectral bands

    Science.gov (United States)

    Dulski, R.; Milewski, S.; Kastek, M.; Trzaskawka, P.; Szustakowski, M.; Ciurapinski, W.; Zyczkowski, M.

    2011-11-01

    Protection of naval bases and harbors requires close co-operation between security and access control systems covering land areas and those monitoring sea approach routes. The typical location of naval bases and harbors - usually next to a large city - makes it difficult to detect and identify a threat in the dense regular traffic of various sea vessels (i.e. merchant ships, fishing boats, tourist ships). Due to the properties of vessel control systems, such as AIS (Automatic Identification System), and the effectiveness of radar and optoelectronic systems against different targets it seems that fast motor boats called RIB (Rigid Inflatable Boat) could be the most serious threat to ships and harbor infrastructure. In the paper the process and conditions for the detection and identification of high-speed boats in the areas of ports and naval bases in the near, medium and far infrared is presented. Based on the results of measurements and recorded thermal images the actual temperature contrast delta T (RIB / sea) will be determined, which will further allow to specify the theoretical ranges of detection and identification of the RIB-type targets for an operating security system. The data will also help to determine the possible advantages of image fusion where the component images are taken in different spectral ranges. This will increase the probability of identifying the object by the multi-sensor security system equipped additionally with the appropriate algorithms for detecting, tracking and performing the fusion of images from the visible and infrared cameras.

  6. Energy levels and far-infrared spectra of oval-shaped nanorings

    Energy Technology Data Exchange (ETDEWEB)

    Gutiérrez, W.; García, L. F.; Mikhailov, I. D. [Escuela de Física, Universidad Industrial de Santander, A. A. 678, Bucaramanga (Colombia)

    2014-05-15

    The evolution of the Aharonov-Bohm oscillation of low-lying states and far infrared spectrum associated to variation of the path curvature for electron motion along nanorings with centerlines in a form of a set of Cassini ovals, whose shape is changed continuously from a single elongated loop to two separated loops is theoretically investigated.

  7. Spectral optical constants of ethanol and isopropanol from ultraviolet to far infrared

    Science.gov (United States)

    Sani, Elisa; Dell'Oro, Aldo

    2016-10-01

    Ethanol and isopropanol are fluids of common use in different branches of materials science. In particular, in the ever growing field of nanoscience, they are dispersing media for nanoparticle suspensions. The knowledge of optical constants of these fluids is required for the characterization of optical properties of nanoparticles, besides providing insights into fundamental properties of fluids themselves. In this work, we calculated the real refractive index n of ethanol and isopropanol applying the Kramers-Kronig theory to the experimentally obtained k spectrum over an extremely wide spectral range, from 181 to ∼ 54000 cm-1.

  8. Energy levels and far-infrared optical absorption of impurity doped semiconductor nanorings: Intense laser and electric fields effects

    Science.gov (United States)

    Barseghyan, M. G.

    2016-11-01

    The effects of electron-impurity interaction on energy levels and far-infrared absorption in semiconductor nanoring under the action of intense laser and lateral electric fields have been investigated. Numerical calculations are performed using exact diagonalization technique. It is found that the electron-impurity interaction and external fields change the energy spectrum dramatically, and also have significant influence on the absorption spectrum. Strong dependence on laser field intensity and electric field of lowest energy levels, also supported by the Coulomb interaction with impurity, is clearly revealed.

  9. Beamed radio and far infrared emission in quasars and radio galaxies

    NARCIS (Netherlands)

    Hoekstra, H; Barthel, PD; Hes, R

    1997-01-01

    Simple orientation model predictions for the radio to far infrared spectral energy distributions of radio-loud AGN are confronted with observations at various radio frequencies. This model is subsequently used to investigate 60 mu m far-infrared data. The results are supportive of the unified scheme

  10. Beamed radio and far infrared emission in quasars and radio galaxies

    NARCIS (Netherlands)

    Hoekstra, H; Barthel, PD; Hes, R

    Simple orientation model predictions for the radio to far infrared spectral energy distributions of radio-loud AGN are confronted with observations at various radio frequencies. This model is subsequently used to investigate 60 mu m far-infrared data. The results are supportive of the unified scheme

  11. A Low-Energy-Spread Rf Accelerator for a Far-Infrared Free-Electron Laser

    NARCIS (Netherlands)

    van der Geer, C. A. J.; Bakker, R. J.; van der Meer, A. F. G.; van Amersfoort, P. W.; Gillespie, W. A.; Saxon, G.; Poole, M. W.

    1993-01-01

    A high electron current and a small energy spread are essential for the operation of a free electron laser (FEL). In this paper we discuss the design and performance of the accelerator for FELIX, the free electron laser for infrared experiments. The system consists of a thermionic gun, a prebuncher,

  12. A low-energy-spread rf accelerator for a far-infrared free electron laser

    Science.gov (United States)

    van der Geer, C. A. J.; Bakker, R. J.; van der Meer, A. F. G.; van Amersfoort, P. W.; Gillespie, W. A.; Saxon, G.; Poole, M. W.

    1993-10-01

    A high electron current and a small energy spread are essential for the operation of a free electron laser (FEL). In this paper we discuss the design and performance of the accelerator for FELIX, the free electron laser for infrared experiments. The system consists of a thermionic gun, a prebuncher, a buncher and two standard commercial linac sections. The gun is operated with a pulse duration of 280 ps and a bunch charge of 200 pC. After compression to 35 ps by the prebuncher, the bunches are accelerated to 4 MeV in the buncher and simultaneously compressed to 6 ps. The principle of the method is that the order of the electrons is conserved in the buncher, so that the resulting more or less linear energy-phase relationship along each bunch can be compensated effectively against space charge forces and the accelerating field gradient in the linacs, via an appropriate choice of the phase of the rf wave. Behind the linacs an rms energy spread of 0.30% has been measured.

  13. Properties of dust in the Galactic center region probed by AKARI far-infrared spectral mapping - detection of a dust feature

    CERN Document Server

    Kaneda, H; Onaka, T; Kawada, M; Murakami, N; Nakagawa, T; Okada, Y; Takahashi, H

    2012-01-01

    We investigate the properties of interstellar dust in the Galactic center region toward the Arches and Quintuplet clusters. With the Fourier Transform Spectrometer of the AKARI/Far-Infrared Surveyor, we performed the far-infrared (60 - 140 cm^-1) spectral mapping of an area of about 10' x 10' which includes the two clusters to obtain a low-resolution (R = 1.2 cm^-1) spectrum at every spatial bin of 30" x 30". We derive the spatial variations of dust continuum emission at different wavenumbers, which are compared with those of the [O III] 88 micron (113 cm^-1) emission and the OH 119 micron (84 cm^-1) absorption. The spectral fitting shows that two dust modified blackbody components with temperatures of ~20 K and ~50 K can reproduce most of the continuum spectra. For some spectra, however, we find that there exists a significant excess on top of a modified blackbody continuum around 80 - 90 cm^-1 (110 - 130 microns). The warmer dust component is spatially correlated well with the [O III] emission and hence lik...

  14. Far-Infrared Spectroscopy of Weakly Bound Hydrated Cluster Molecules

    DEFF Research Database (Denmark)

    Andersen, Jonas

    -sized molecular clusters with water by means of far-infrared and terahertz neon matrix isolation spectroscopy. The embedding of non-covalent cluster molecules in solid cryogenic neon matrices at 2.8 K ensures a high sensitivity for direct spectroscopic observations of the large-amplitude intermolecular...... vibrational bands of the cluster molecules in the challenging far-infrared and terahertz spectral regions.A key parameter in the validation of the performance of theoretical predictions for weak non-covalent intermolecular interactions is the dissociation energy D0 that depends heavily on the class of large...

  15. Far-infrared polarimetry

    Science.gov (United States)

    Hildebrand, Roger H.; Dotson, Jesse L.; Dowell, C. Darren; Platt, S. R.; Schleuning, David; Davidson, J. A.; Novak, Giles

    1995-01-01

    Airborne observations with the The University of Chicago polarimeter, Stokes (Platt et al. 1991), have produced maps of far infrared polarization over large areas in molecular clouds. Subsequent papers will discuss the implications of the results concerning the magnetic fields of individual objects. Our purpose here is to show a broad sample of the results and to point out certain general characteristics of the polarized emission.

  16. The far-infrared energy distributions of Seyfert and starburst galaxies in the Local Universe ISO photometry of the 12 micron active galaxy sample

    CERN Document Server

    Spinoglio, L; Malkan, M A; Spinoglio, Luigi; Andreani, Paola; Malkan, Matthew A.

    2002-01-01

    New far-infrared photometry with ISOPHOT, onboard the Infrared Space Observatory, is presented for 58 galaxies with homogeneous published data for another 32 galaxies all belonging to the 12 micron galaxy sample. In total 29 Seyfert 1's, 35 Seyfert 2's and 12 starburst galaxies, about half of the 12 micron active galaxy sample, plus 14 normal galaxies for comparison. The ISO and the IRAS data are used to define color-color diagrams and spectral energy distributions (SED). Thermal dust emission at two temperatures (one cold at 15-30K and one warm at 50-70K) can fit the 60-200 micron SED, with a dust emissivity law proportional to the inverse square of the wavelength. Seyfert 1's and Seyfert 2's are indistinguishable longward of 100 micron, while, as already seen by IRAS, the former have flatter SEDs shortward of 60 micron. A mild anti-correlation is found between the [200 - 100] color and the "60 micron excess". We infer that this is due to the fact that galaxies with a strong starburst component, and thus a s...

  17. Simultaneous retrieval of water vapour, temperature and cirrus clouds properties from measurements of far infrared spectral radiance over the Antarctic Plateau

    Science.gov (United States)

    Di Natale, Gianluca; Palchetti, Luca; Bianchini, Giovanni; Del Guasta, Massimo

    2017-03-01

    The possibility separating the contributions of the atmospheric state and ice clouds by using spectral infrared measurements is a fundamental step to quantifying the cloud effect in climate models. A simultaneous retrieval of cloud and atmospheric parameters from infrared wideband spectra will allow the disentanglement of the spectral interference between these variables. In this paper, we describe the development of a code for the simultaneous retrieval of atmospheric state and ice cloud parameters, and its application to the analysis of the spectral measurements acquired by the Radiation Explorer in the Far Infrared - Prototype for Applications and Development (REFIR-PAD) spectroradiometer, which has been in operation at Concordia Station on the Antarctic Plateau since 2012. The code performs the retrieval with a computational time that is comparable with the instrument acquisition time. Water vapour and temperature profiles and the cloud optical and microphysical properties, such as the generalised effective diameter and the ice water path, are retrieved by exploiting the 230-980 cm-1 spectral band. To simulate atmospheric radiative transfer, the Line-By-Line Radiative Transfer Model (LBLRTM) has been integrated with a specifically developed subroutine based on the δ-Eddington two-stream approximation, whereas the single-scattering properties of cirrus clouds have been derived from a database for hexagonal column habits. In order to detect ice clouds, a backscattering and depolarisation lidar, co-located with REFIR-PAD has been used, allowing us to infer the position and the cloud thickness to be used in the retrieval. A climatology of the vertical profiles of water vapour and temperature has been performed by using the daily radiosounding available at the station at 12:00 UTC. The climatology has been used to build an a priori profile correlation to constrain the fitting procedure. An optimal estimation method with the Levenberg-Marquardt approach has been

  18. FIRI-A far-infrared interferometer

    NARCIS (Netherlands)

    Helmich, Frank P.; Ivison, R. J.

    2009-01-01

    Half of the energy ever emitted by stars and accreting objects comes to us in the far-infrared (FIR) waveband and has yet to be properly explored. We propose a powerful Far-InfraRed Interferometer mission, FIRI, to carry out high-resolution imaging spectroscopy in the FIR. This key observational cap

  19. $\\alpha$ Centauri A in the far infrared

    CERN Document Server

    Liseau, R; Olofsson, G; Bryden, G; Marshall, J P; Ardila, D; Aran, A Bayo; Danchi, W C; del Burgo, C; Eiroa, C; Ertel, S; Fridlund, M C W; Krivov, A V; Pilbratt, G L; Roberge, A; Thébault, P; Wiegert, J; White, G J

    2012-01-01

    Chromospheres and coronae are common phenomena on solar-type stars. Understanding the energy transfer to these heated atmospheric layers requires direct access to the relevant empirical data. Study of these structures has, by and large, been limited to the Sun thus far. The region of the temperature reversal can be directly observed only in the far infrared and submm. We aim at the determination of the characteristics of the atmosphere in the region of the temperature minimum of the solar sister star alpha Cen A. For the nearby binary system alpha Centauri, stellar parameters are known with high accuracy from measurements. For the basic model parameters Teff, log g and [Fe/H], we interpolate in the grid of GAIA/PHOENIX stellar model atmospheres and compute the corresponding model for the G2 V star alpha Cen A. Comparison with photometric measurements shows excellent agreement between observed photospheric data in the optical and infrared. For longer wavelengths, the modelled spectral energy distribution is co...

  20. Multi-layer Far-Infrared Component Technology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I SBIR will demonstrate the feasibility of a process to create multi-layer thin-film optics for the far-infrared/sub-millimeter wave spectral region. The...

  1. Long-slit optical spectroscopy of powerful far-infrared galaxies - The nature of the nuclear energy source

    Science.gov (United States)

    Armus, Lee; Heckman, Timothy M.; Miley, George K.

    1989-01-01

    Optical spectroscopic data are presented for a sample of 47 powerful far-IR galaxies chosen for IR spectral shape, and for six other IR-bright galaxies. The stellar absorption lines expected from a population of old stars are generally very weak in the nuclei of the galaxies. Very weak Mg I absorption is found in regions well off the nucleus, implying that the visible spectrum is dominated by young stars and not by an AGN. At least one, and probably five, of the galaxies have detectable WR emission features, providing additional evidence for a young stellar population. About 20 percent of the galaxies have strong Balmer absorption lines, indicating the presence of a substantial intermediate-age stellar population. The equivalent width of the H-alpha emission line can be modeled as arising from a mixture of a large young population and an intermediate-age population of stars.

  2. Long-slit optical spectroscopy of powerful far-infrared galaxies - The nature of the nuclear energy source

    Science.gov (United States)

    Armus, Lee; Heckman, Timothy M.; Miley, George K.

    1989-01-01

    Optical spectroscopic data are presented for a sample of 47 powerful far-IR galaxies chosen for IR spectral shape, and for six other IR-bright galaxies. The stellar absorption lines expected from a population of old stars are generally very weak in the nuclei of the galaxies. Very weak Mg I absorption is found in regions well off the nucleus, implying that the visible spectrum is dominated by young stars and not by an AGN. At least one, and probably five, of the galaxies have detectable WR emission features, providing additional evidence for a young stellar population. About 20 percent of the galaxies have strong Balmer absorption lines, indicating the presence of a substantial intermediate-age stellar population. The equivalent width of the H-alpha emission line can be modeled as arising from a mixture of a large young population and an intermediate-age population of stars.

  3. The Galactic Centre in the Far Infrared

    CERN Document Server

    Etxaluze, M; Tolls, V; Stark, A A; Gonzalez-Alfonso, E

    2011-01-01

    We analyse the far infrared dust emission from the Galactic Centre region, including the Circumnuclear Disk (CND) and other structures, using Herschel PACS and SPIRE photometric observations. These Herschel data are complemented by unpublished observations by the Infrared Space Observatory Long Wavelength Spectrometer (ISO LWS), which used parallel mode scans to obtain photometric images of the region with a larger beam than Herschel but with a complementary wavelength coverage and more frequent sampling with ten detectors observing at ten different wavelengths in the range from 46 to 180 \\mum, where the emission peaks. We also include data from the MSX at 21.3 \\mum for completeness. We model the combined ISO LWS continuum plus Herschel PACS and SPIRE photometric data toward the central 2 pc in Sgr A*, a region that includes the CND. We find that the FIR spectral energy distribution is best represented by a continuum that is the sum of three greybody curves from dust at temperatures of 90, 44.5, and 23 K. We ...

  4. The far-infrared behaviour of Herbig Ae/Be discs: Herschel PACS photometry

    CERN Document Server

    Pascual, N; Meeus, G; Marshall, J P; Mendigutía, I; Sandell, G

    2016-01-01

    Herbig Ae/Be objects are pre-main sequence stars surrounded by gas- and dust-rich circumstellar discs. These objects are in the throes of star and planet formation, and their characterisation informs us of the processes and outcomes of planet formation processes around intermediate mass stars. Here we analyse the spectral energy distributions of disc host stars observed by the Herschel Open Time Key Programme `Gas in Protoplanetary Systems'. We present Herschel/PACS far-infrared imaging observations of 22 Herbig Ae/Bes and 5 debris discs, combined with ancillary photometry spanning ultraviolet to sub-millimetre wavelengths. From these measurements we determine the diagnostics of disc evolution, along with the total excess, in three regimes spanning near-, mid-, and far-infrared wavelengths. Using appropriate statistical tests, these diagnostics are examined for correlations. We find that the far-infrared flux, where the disc becomes optically thin, is correlated with the millimetre flux, which provides a meas...

  5. Herschel Far-Infrared Spectral-mapping of Orion BN/KL Outflows: Spatial distribution of excited CO, H2O, OH, O and C+ in shocked gas

    CERN Document Server

    Goicoechea, Javier R; Cernicharo, Jose; Neufeld, David A; Vavrek, Roland; Bergin, Edwin A; Cuadrado, Sara; Encrenaz, Pierre; Etxaluze, Mireya; Melnick, Gary J; Polehampton, Edward

    2014-01-01

    We present ~2'x2' spectral-maps of Orion BN/KL outflows taken with Herschel at ~12'' resolution. For the first time in the far-IR domain, we spatially resolve the emission associated with the bright H2 shocked regions "Peak 1" and "Peak 2" from that of the Hot Core and ambient cloud. We analyze the ~54-310um spectra taken with the PACS and SPIRE spectrometers. More than 100 lines are detected, most of them rotationally excited lines of 12CO (up to J=48-47), H2O, OH, 13CO, and HCN. Peaks 1/2 are characterized by a very high L(CO)/L(FIR)~5x10^{-3} ratio and a plethora of far-IR H2O emission lines. The high-J CO and OH lines are a factor ~2 brighter toward Peak 1 whereas several excited H2O lines are ~50% brighter toward Peak 2. A simplified non-LTE model allowed us to constrain the dominant gas temperature components. Most of the CO column density arises from Tk~200-500 K gas that we associate with low-velocity shocks that fail to sputter grain ice mantles and show a maximum gas-phase H2O/CO~10^{-2} abundance r...

  6. The Far Infrared and Submillimeter Diffuse Extragalactic Background

    CERN Document Server

    Hauser, M G

    2001-01-01

    The cosmic infrared background (CIB) radiation was a long-sought fossil of energetic processes associated with structure formation and chemical evolution since the Big Bang. The COBE Diffuse Infrared Background Experiment (DIRBE) and Far Infrared Absolute Spectrophotometer (FIRAS) were specifically designed to search for this background from 1.25 microns to millimeter wavelengths. These two instruments provided high quality, absolutely calibrated all-sky maps which have enabled the first detections of the CIB, initially at far infrared and submillimeter wavelengths, and more recently in the near infrared as well. The aim of this paper is to review the status of determinations of the CIB based upon COBE measurements. The results show that the energy in the CIB from far infrared to millimeter wavelengths is comparable to that in the integrated light of galaxies from UV to near infrared wavelengths: the universe had a luminous but dusty past. On the assumption that nucleosynthesis in stars is the energy source f...

  7. Mesoporous Silicon Far Infrared Filters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I proposal describes a novel method to make optical filters based on mesoporous silicon multilayers, for use at cold temperatures in the far infrared...

  8. Far infrared absorption by acoustic phonons in titanium dioxide nanopowders

    OpenAIRE

    Murray, Daniel B.; Netting, Caleb H.; Saviot, Lucien; Pighini, Catherine; Millot, Nadine; Aymes, Daniel; Liu, Hsiang-Lin

    2006-01-01

    We report spectral features of far infrared electromagnetic radiation absorption in anatase TiO2 nanopowders which we attribute to absorption by acoustic phonon modes of nanoparticles. The frequency of peak excess absorption above the background level corresponds to the predicted frequency of the dipolar acoustic phonon from continuum elastic theory. The intensity of the absorption cannot be accounted for in a continuum elastic dielectric description of the nanoparticle material. Quantum mech...

  9. Brown dwarf disks with Herschel: Linking far-infrared and (sub)-mm fluxes

    CERN Document Server

    Daemgen, Sebastian; Scholz, Alexander; Testi, Leonardo; Jayawardhana, Ray; Greaves, Jane; Eastwood, Daniel

    2016-01-01

    Brown dwarf disks are excellent laboratories to test our understanding of disk physics in an extreme parameter regime. In this paper we investigate a sample of 29 well-characterized brown dwarfs and very low mass stars, for which Herschel far-infrared fluxes as well as (sub)-mm fluxes are available. We have measured new Herschel PACS fluxes for 11 objects and complement these with (sub)-mm data and Herschel fluxes from the literature. We analyze their spectral energy distributions in comparison with results from radiative transfer modeling. Fluxes in the far-infrared are strongly affected by the shape and temperature of the disk (and hence stellar luminosity), whereas the (sub)-mm fluxes mostly depend on disk mass. Nevertheless, there is a clear correlation between far-infrared and (sub)-mm fluxes. We argue that the link results from the combination of the stellar mass-luminosity relation and a scaling between disk mass and stellar mass. We find strong evidence of dust settling to the disk midplane. The spect...

  10. Development of Kinetic Inductance Detectors for Far-Infrared Spectroscopy

    Science.gov (United States)

    Barlis, Alyssa; Aguirre, James E.; Stevenson, Thomas

    2016-01-01

    An instrument with high sensitivity and spectral resolution at far-infrared wavelengths could contribute significantly to several currently unanswered questions in astrophysics. Here, we describe a detector system suitable for a spectroscopic experiment at far-infrared wavelengths using kinetic inductance detectors (KIDs). KIDs have the potential to achieve high sensitivity and low noise levels. Specifically, the approach we take uses lumped-element KIDs, which consist of separate capacitive and inductive elements combined to form a microresonator. The inductive element serves as a direct radiation absorber. We describe the design considerations, fabrication process, and readout scheme for a prototype LEKID array of 1600 pixels, along with results from a prototype detector array.

  11. Electromagnetic modelling of a space-borne far-infrared interferometer

    Science.gov (United States)

    Donohoe, Anthony; O'Sullivan, Créidhe; Murphy, J. Anthony; Bracken, Colm; Savini, Giorgio; Pascale, Enzo; Ade, Peter; Sudiwala, Rashmi; Hornsby, Amber

    2016-02-01

    In this paper I will describe work done as part of an EU-funded project `Far-infrared space interferometer critical assessment' (FISICA). The aim of the project is to investigate science objectives and technology development required for the next generation THz space interferometer. The THz/FIR is precisely the spectral region where most of the energy from stars, exo-planetary systems and galaxy clusters deep in space is emitted. The atmosphere is almost completely opaque in the wave-band of interest so any observation that requires high quality data must be performed with a space-born instrument. A space-borne far infrared interferometer will be able to answer a variety of crucial astrophysical questions such as how do planets and stars form, what is the energy engine of most galaxies and how common are the molecule building blocks of life. The FISICA team have proposed a novel instrument based on a double Fourier interferometer that is designed to resolve the light from an extended scene, spectrally and spatially. A laboratory prototype spectral-spatial interferometer has been constructed to demonstrate the feasibility of the double-Fourier technique at far infrared wavelengths (0.15 - 1 THz). This demonstrator is being used to investigate and validate important design features and data-processing methods for future instruments. Using electromagnetic modelling techniques several issues related to its operation at long baselines and wavelengths, such as diffraction, have been investigated. These are critical to the design of the concept instrument and the laboratory testbed.

  12. Far-infrared spectroscopy of interstellar dust

    NARCIS (Netherlands)

    Tielens, AGGM; Wilson, A

    2005-01-01

    The composition of interstellar dust is best studied using mid-infrared spectroscopy. Nevertheless, the far-infrared can make some unique contributions to this field. This includes studies on the Mg/Fe ratio and the temperature of crystalline silicates, the presence of carbonates, and the precense o

  13. The Galactic Center in the Far-infrared

    Science.gov (United States)

    Etxaluze, M.; Smith, Howard A.; Tolls, V.; Stark, A. A.; González-Alfonso, E.

    2011-10-01

    We analyze the far-infrared dust emission from the Galactic center region, including the circumnuclear disk (CND) and other structures, using Herschel PACS and SPIRE photometric observations. These Herschel data are complemented by unpublished observations by the Infrared Space Observatory Long Wavelength Spectrometer (ISO-LWS), which used parallel mode scans to obtain photometric images of the region with a larger beam than Herschel but with a complementary wavelength coverage and more frequent sampling with 10 detectors observing at 10 different wavelengths in the range from 46 μm to 180 μm, where the emission peaks. We also include data from the Midcourse Space Experiment at 21.3 μm for completeness. We model the combined ISO-LWS continuum plus Herschel PACS and SPIRE photometric data toward the central 2 pc in Sagittarius A* (Sgr A*), a region that includes the CND. We find that the far-infrared spectral energy distribution is best represented by a continuum that is the sum of three gray body curves from dust at temperatures of 90, 44.5, and 23 K. We obtain temperature and molecular hydrogen column density maps of the region. We estimate the mass of the inner part of the CND to be ~5.0 × 104 M sun, with luminosities: L cavity ~ 2.2 × 106 L sun and L CND ~ 1.5 × 106 L sun in the central 2 pc radius around Sgr A*. We find from the Herschel and ISO data that the cold component of the dust dominates the total dust mass, with a contribution of ~3.2 × 104 M sun; this important cold material had escaped the notice of earlier studies that relied on shorter wavelength observations. The hotter component disagrees with some earlier estimates, but is consistent with measured gas temperatures and with models that imply shock heating or turbulent effects are at work. We find that the dust grain sizes apparently change widely across the region, perhaps in response to the temperature variations, and we map that distribution.

  14. Observability of localized magnetoplasmons in quantum dots: Scrutinizing the eligibility of far-infrared, Raman, and electron-energy-loss spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Kushwaha, Manvir S. [Department of Physics and Astronomy, Rice University, P.O. Box 1892, Houston, Texas 77251 (United States)

    2016-03-15

    We investigate a one-component, quasi-zero dimensional, quantum plasma exposed to a parabolic potential and an applied magnetic field in the symmetric gauge. If the size of such a system as can be realized in the semiconducting quantum dots is on the order of the de-Broglie wavelength, the electronic and optical properties become highly tunable. Then the quantum size effects challenge the observation of many-particle phenomena such as the magneto-optical absorption, Raman intensity, and electron energy-loss spectrum. An exact analytical solution of the problem leads us to infer that these many-particle phenomena are, in fact, dictated by the generalized Kohn’s theorem (GKT) in the long-wavelength limit. Maneuvering the confinement and/or the magnetic field furnishes the resonance energies capable of being explored with the FIR, Raman, and/or electron-energy-loss spectroscopy. This implies that either of these probes is competent in observing the localized magnetoplasmons in the system. As an application of the rigorous analytical diagnosis of the system, we have presented various pertinent single-particle, such as Fock-Darwin spectrum, Fermi energy, zigzag excitation spectrum, and magneto-optical transitions, and the many-particle phenomena, such as magneto-optical absorption, Raman intensity, and electron energy-loss probability. In the latter, the energy position of the resonance peaks is observed to be independent of the electron-electron interactions and hence of the number of electrons in the quantum dot in compliance with the GKT. It is found that both confinement potential and magnetic field play a decisive role in influencing the aforementioned many-particle phenomena. Specifically, increasing (decreasing) the strength of the confining potential is found to be analogous to shrinking (expanding) the size of the quantum dots and results into a blue (red) shift in the respective spectra. Intensifying the magnetic field has two-fold effects in the resonance

  15. Far infrared study of polymorphism of trimethylchlorosilane

    Science.gov (United States)

    Godlewska, M.; Kocot, A.; Mayer, J.; Ściesińska, E.; Ściesiński, J.

    1984-03-01

    The far infrared spectra in the range of 16 - 500 cm -1 for (CH 3) 3SiCl were measured in the temperature range of 90 - 300 K by the use of Fourier transform technique. Two solid phases were found, the high-temperature phase being easily supercooled down to liquid nitrogen temperature. On the basis of the characteristic features of the spectra suggestions concerning the structure of the low-temperature phase are given.

  16. The Berkeley tunable far infrared laser spectrometers

    Science.gov (United States)

    Blake, G. A.; Laughlin, K. B.; Cohen, R. C.; Busarow, K. L.; Gwo, D.-H.

    1991-01-01

    A detailed description is presented for a tunable far infrared laser spectrometer based on frequency mixing of an optically pumped molecular gas laser with tunable microwave radiation in a Schottky point contact diode. The system has been operated on over 30 laser lines in the range 10-100/cm and exhibits a maximum absorption sensitivity near one part in a million. Each laser line can be tuned by + or - 110 GHz with first-order sidebands.

  17. 6 MeV storage ring dedicated to hard X-ray imaging and far-infrared spectroscopy

    Indian Academy of Sciences (India)

    M M Haque; A Moon; T Hirai; H Yamada

    2011-02-01

    The tabletop storage ring, 6 MeV MIRRORCLE, is dedicated to hard X-ray imaging as well as far-infrared (FIR) spectroscopy. In spite of low electron energy, the 6 MeV MIRRORCLE generates hard X-rays ranging from 10 keV up to its electron energy and milliwatt order submillimetre range FIR rays. Bremsstrahlung is the mechanism for the hard X-ray generation. Images produced with 11 × geometrical magnification display a sharply enhanced edge effect when generated using a 25 mm rod electron target. Bright far-infrared is generated in the same way using a conventional synchrotron light source, but with MIRRORCLE the spectral flux is found to be ∼ 1000 times greater than that of a standard thermal source. Partially coherent enhancement is observed in the case of FIR output.

  18. Reststrahlen Band Optics for the Advancement of Far-Infrared Optical Architecture

    Science.gov (United States)

    Streyer, William Henderson

    . Computational models of the emission indicated the samples had significantly higher power efficiency than a blackbody at the same temperature in the same wavelength band. Chapter 5 presents selective thermal emission in the far-infrared from samples of patterned gallium phosphide. The selective absorption of the samples occurs in the material's Reststrahlen band and can be attributed to surface phonon polariton modes. The surfaces of the samples were grated via wet etching to provide the additional momentum necessary for free space photons to couple into and out of the surface phonon polariton modes. Upon heating the samples, selective thermal emission of the surface phonon polariton modes was observed. Chapter 6 investigates a potential means of linking lattice vibrations to free space photons. Lightly doped films of gallium arsenide were grown by molecular beam epitaxy and wet etched with 1D gratings. The light doping served to modify the material's intrinsic permittivity and extend the region of its Reststrahlen band. Though the extension of the region with negative real permittivity was small, it extended beyond the longitudinal optical phonon energy of the material, which stands as the high energy boundary of the unmodified material's Reststrahlen band. Hybrid surface polariton modes were observed at energies near the longitudinal optical phonon energy where they are not supported on the surface of the intrinsic material -- offering a potential bridge between bulk optical phonon populations and free space photons. Chapter 7 presents preliminary results exploring the prospect of exploiting an absorption resonance known as the Berreman mode as a mechanism to link optical phonons to free space photons. The Berreman mode is a strong absorption resonance that occurs near the longitudinal optical phonon energy at moderate angles of incidence in polar semiconductors. Preliminary results demonstrate selective thermal emission consistent with the expected spectral position of the

  19. Far infrared studies of solid cyclohexane

    Science.gov (United States)

    Sciesinska, E.; Sciesinski, J.; Wasiutynski, T.; Godlewska, M.; Wurflinger, A.

    1992-03-01

    Far infrared spectra of cyclohexane C 6H 12 in the frequency range of 100 - 650 cm -1 and C 6D 12 in the range of 50 - 650 cm -1 for phases I and II were measured at various temperatures. In the spectra some Raman active internal modes are observed. Four crystal multiplet components of the ν 16(e u) mode for phase II are resolved and assigned using the oriented gas model. Temperature dependence of the ν 32(e u) and ν 16(a 2u) vibrational excitons for phase II is discussed.

  20. Kinetic inductance detectors for far-infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barlis, A., E-mail: abarlis@physics.upenn.edu [University of Pennsylvania Department of Physics and Astronomy, Philadelphia, Pennsylvania (United States); Aguirre, J. [University of Pennsylvania Department of Physics and Astronomy, Philadelphia, Pennsylvania (United States); Stevenson, T. [NASA Goddard Space Flight Center, Greenbelt, Maryland (United States)

    2016-07-11

    The star formation mechanisms at work in the early universe remain one of the major unsolved problems of modern astrophysics. Many of the luminous galaxies present during the period of peak star formation (at redshift of about 2.5) were heavily enshrouded in dust, which makes observing their properties difficult at optical wavelengths. However, many spectral lines exist at far-infrared wavelengths that serve as tracers of star formation. Here, we describe a detector system suitable for a balloon-borne spectroscopic intensity mapping experiment at far-infrared wavelengths. The system uses lumped-element kinetic inductance detectors (KIDs), which have the potential to achieve high sensitivity and low noise levels. KIDs consist of separate capacitive and inductive elements, and use the inductive element as the radiation absorber. We describe the design considerations, fabrication process, and readout scheme for a prototype LEKID array of 1600 pixels. - Highlights: • We describe a concept for a balloon-borne telescope for far-IR wavelengths. • Telescope would use high-sensitivity kinetic inductance detectors. • Design considerations and fabrication process for prototype detectors.

  1. Constraining the Lyα escape fraction with far-infrared observations of Lyα emitters

    Energy Technology Data Exchange (ETDEWEB)

    Wardlow, Julie L.; Calanog, J.; Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Malhotra, S.; Zheng, Z.; Rhoads, J. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Finkelstein, S. [The University of Texas at Austin, Austin, TX 78712 (United States); Bock, J.; Bridge, C. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Ciardullo, R.; Gronwall, C. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Gawiser, E. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Heinis, S. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Ibar, E. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Ivison, R. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Marsden, G. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Oliver, S. J. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Riechers, D., E-mail: jwardlow@dark-cosmology.dk [Department of Astronomy, Space Science Building, Cornell University, Ithaca, NY 14853-6801 (United States); and others

    2014-05-20

    We study the far-infrared properties of 498 Lyα emitters (LAEs) at z = 2.8, 3.1, and 4.5 in the Extended Chandra Deep Field-South, using 250, 350, and 500 μm data from the Herschel Multi-tiered Extragalactic Survey and 870 μm data from the LABOCA ECDFS Submillimeter Survey. None of the 126, 280, or 92 LAEs at z = 2.8, 3.1, and 4.5, respectively, are individually detected in the far-infrared data. We use stacking to probe the average emission to deeper flux limits, reaching 1σ depths of ∼0.1 to 0.4 mJy. The LAEs are also undetected at ≥3σ in the stacks, although a 2.5σ signal is observed at 870 μm for the z = 2.8 sources. We consider a wide range of far-infrared spectral energy distributions (SEDs), including an M82 and an Sd galaxy template, to determine upper limits on the far-infrared luminosities and far-infrared-derived star formation rates of the LAEs. These star formation rates are then combined with those inferred from the Lyα and UV emission to determine lower limits on the LAEs' Lyα escape fraction (f {sub esc}(Lyα)). For the Sd SED template, the inferred LAEs f {sub esc}(Lyα) are ≳ 30% (1σ) at z = 2.8, 3.1, and 4.5, which are all significantly higher than the global f {sub esc}(Lyα) at these redshifts. Thus, if the LAEs f {sub esc}(Lyα) follows the global evolution, then they have warmer far-infrared SEDs than the Sd galaxy template. The average and M82 SEDs produce lower limits on the LAE f {sub esc}(Lyα) of ∼10%-20% (1σ), all of which are slightly higher than the global evolution of f {sub esc}(Lyα), but consistent with it at the 2σ-3σ level.

  2. High resolution spectroscopy in the microwave and far infrared

    Science.gov (United States)

    Pickett, Herbert M.

    1990-01-01

    High resolution rotational spectroscopy has long been central to remote sensing techniques in atmospheric sciences and astronomy. As such, laboratory measurements must supply the required data to make direct interpretation of data for instruments which sense atmospheres using rotational spectra. Spectral measurements in the microwave and far infrared regions are also very powerful tools when combined with infrared measurements for characterizing the rotational structure of vibrational spectra. In the past decade new techniques were developed which have pushed high resolution spectroscopy into the wavelength region between 25 micrometers and 2 mm. Techniques to be described include: (1) harmonic generation of microwave sources, (2) infrared laser difference frequency generation, (3) laser sideband generation, and (4) ultrahigh resolution interferometers.

  3. Early results from the Far Infrared Absolute Spectrophotometer (FIRAS)

    Science.gov (United States)

    Mather, J. C.; Cheng, E. S.; Shafer, R. A.; Eplee, R. E.; Isaacman, R. B.; Fixsen, D. J.; Read, S. M.; Meyer, S. S.; Weiss, R.; Wright, E. L.

    1991-01-01

    The Far Infrared Absolute Spectrophotometer (FIRAS) on the Cosmic Background Explorer (COBE) mapped 98 percent of the sky, 60 percent of it twice, before the liquid helium coolant was exhausted. The FIRAS covers the frequency region from 1 to 100/cm with a 7 deg angular resolution. The spectral resolution is 0.2/cm for frequencies less than 20/cm and 0.8/cm for higher frequencies. Preliminary results include: a limit on the deviations from a Planck curve of 1 percent of the peak brightness from 1 to 20/cm, a temperature of 2.735 +/- 0.06 K, a limit on the Comptonization parameter y of 0.001, on the chemical potential parameter mu of 0.01, a strong limit on the existence of a hot smooth intergalactic medium, and a confirmation that the dipole anisotropy spectrum is that of a Doppler shifted blackbody.

  4. Kinetic inductance detectors for far-infrared spectroscopy

    Science.gov (United States)

    Barlis, Alyssa; Aguirre, James; Stevenson, Thomas

    2016-07-01

    The star formation mechanisms at work in the early universe remain one of the major unsolved problems of modern astrophysics. Many of the luminous galaxies present during the period of peak star formation (between redshifts 1 and 3) were heavily enshrouded in dust, which makes observing their properties difficult at optical wavelengths. However, many spectral lines exist at far-infrared wavelengths that serve as tracers of star formation during that period, in particular fine structure lines of nitrogen, carbon, and oxygen, as well as the carbon monoxide molecule. Using an observation technique known as intensity mapping, it would be possible to observe the total line intensity for a given redshift range even without detecting individual sources. Here, we describe a detector system suitable for a balloonborne spectroscopic intensity mapping experiment at far-infrared wavelengths. The experiment requires an "integralfield" type spectrograph, with modest spectral resolution (R 100) for each of a number of spatial pixels spanning several octaves in wavelength. The detector system uses lumped-element kinetic inductance detectors (LEKIDs), which have the potential to achieve the high sensitivity, low noise, and high multiplexing factor required for this experiment. We detail the design requirements and considerations, and the fabrication process for a prototype LEKID array of 1600 pixels. The pixel design is driven by the need for high responsivity, which requires a small physical volume for the LEKID inductor. In order to minimize two-level system noise, the resonators include large-area interdigitated capacitors. High quality factor resonances are required for a large frequency multiplexing factor. Detectors were fabricated using both trilayer TiN/Ti/TiN recipes and thin-film Al, and are operated at base temperatures near 250 mK.

  5. Low cost, high performance far infrared microbolometer

    Science.gov (United States)

    Roer, Audun; Lapadatu, Adriana; Elfving, Anders; Kittilsland, Gjermund; Hohler, Erling

    2010-04-01

    Far infrared (FIR) is becoming more widely accepted within the automotive industry as a powerful sensor to detect Vulnerable Road Users like pedestrians and bicyclist as well as animals. The main focus of FIR system development lies in reducing the cost of their components, and this will involve optimizing all aspects of the system. Decreased pixel size, improved 3D process integration technologies and improved manufacturing yields will produce the necessary cost reduction on the sensor to enable high market penetration. The improved 3D process integration allows a higher fill factor and improved transmission/absorption properties. Together with the high Thermal Coefficient of Resistance (TCR) and low 1/f noise properties provided by monocrystalline silicon germanium SiGe thermistor material, they lead to bolometer performances beyond those of existing devices. The thermistor material is deposited and optimized on an IR wafer separated from the read-out integrated circuit (ROIC) wafer. The IR wafer is transferred to the ROIC using CMOS compatible processes and materials, utilizing a low temperature wafer bonding process. Long term vacuum sealing obtained by wafer scale packaging enables further cost reductions and improved quality. The approach allows independent optimization of ROIC and thermistor material processing and is compatible with existing MEMS-foundries, allowing fast time to market.

  6. Two instruments for far-infrared astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Bonomo, J.L.

    1983-05-01

    Two instruments for far-infrared astrophysics are described. The first is a broad-band photometer used on White Mountain for astronomical observations from 10 to 30 cm/sup -1/ (300 GHz to 1 THz; lambda, 1 mm to 330 ..mu..). The optical system of the telescope includes a light-weight, high-speed, chopping secondary. The L /sup 4/He-cooled photometer uses low-pass filters and a L/sup 3/He-cooled, composite bolometer. The system performance is evaluated, and the site is compared to other possible platforms. The second project is a balloon-borne spectroradiometer to measure the cosmic background radiation from 3 to 10 cm/sup -1/ (100 GHz to 300 GHz; lambda, 3 mm to 1 mm). The apparatus has five band-pass filters with excellent rejection at higher frequencies, a low-noise chopper, and an internal calibrator. We describe the design and use of calibrators for such an experiment and develop a model of calibration procedures. The calibrations of several reported measurements are analyzed with this model, and flaws are found in one procedure. Finally, the system performance is used to estimate the accuracy this experiment can achieve.

  7. The research of far infrared flame retardant polyester staple fiber

    Science.gov (United States)

    Li, Qingshan; Zhang, Kaijun; Luo, Jinqong; Li, Ji’an; Jiang, Jian; Liang, Qianqian; Jin, Yongxia; Liu, Bing

    2017-01-01

    Far infrared flame retardant slices was prepared, fiber with far infrared flame retardant composite function was also prepared by the method of melt spinning. Scanning electron microscopy (SEM) was used to observe the fibrous microscopic structure. In the SEM images, functional ultrafine powder particle size and distribution in the fiber were visible. The results show that the functional ultrafine powder is evenly distributed on the fibrous surface, which is closely combined with fiber, and the far infrared emissivity is F, which is more than (8 to 14 microns) 0.88. Far infrared flame retardant polyester fiber has not only good flame retardant, but also environmental health effect: releasing negative ions and launch far-infrared, which shows wide application prospect. The fiber was processed into far-infrared flame retardant electric blanket, whose functional indicators and flame retardant properties are not reduced.

  8. Far-infrared spectroscopic study of CeO{sub 2} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Popović, Z. V., E-mail: zoran.popovic@ipb.ac.rs; Grujić-Brojčin, M.; Paunović, N. [University of Belgrade, Center for Solid State Physics and New Materials, Institute of Physics (Serbia); Radonjić, M. M. [University of Belgrade, Scientific Computing Laboratory, Institute of Physics Belgrade (Serbia); Araújo, V. D.; Bernardi, M. I. B. [Universidade de São Paulo-USP, Instituto de Fisica (Brazil); Lima, M. M. de; Cantarero, A. [Universidad de Valencia, Instituto de Ciencia de Los Materiales (Spain)

    2015-01-15

    We present the far-infrared reflectivity spectra of 5 nm-sized pure and copper-doped Ce{sub 1−x}Cu{sub x}O{sub 2−y} (x = 0; 0.01 and 0.10) nanocrystals measured at room temperature in the 50–650 cm{sup −1} spectral range. Reflectivity spectra were analyzed using the factorized form of the dielectric function, which includes the phonon and the free carriers contribution. Four oscillators with TO energies of approximately 135, 280, 370, and 490 cm{sup −1} were included in the fitting procedure. These oscillators represent local maxima of the CeO{sub 2} phonon density of states, which is also calculated using the density functional theory. The lowest energy oscillator represents TA(L)/TA(X) phonon states, which become infrared-active E{sub u} modes at the L and X points of the Brillouin zone (BZ). The second oscillator originates from TO(Γ) phonon states. The oscillator at ∼400 cm{sup −1} originates from Raman mode phonon states, which at the L point of BZ also becomes infrared-active E{sub u} mode. The last oscillator describes phonons with dominantly LO(Γ) infrared mode character. The appearance of phonon density of states related oscillators, instead of single F{sub 2u}infrared-active mode in the far-infrared reflectivity spectra, is a consequence of the nanosized dimension of the CeO{sub 2} particles. The best fit spectra are obtained using the generalized Bruggeman model for inhomogeneous media, which takes into account the nanocrystal volume fraction and the pore shape.

  9. Doping of germanium and silicon crystals with non-hydrogenic acceptors for far infrared lasers

    Science.gov (United States)

    Haller, Eugene E.; Brundermann, Erik

    2000-01-01

    A method for doping semiconductors used for far infrared lasers with non-hydrogenic acceptors having binding energies larger than the energy of the laser photons. Doping of germanium or silicon crystals with beryllium, zinc or copper. A far infrared laser comprising germanium crystals doped with double or triple acceptor dopants permitting the doped laser to be tuned continuously from 1 to 4 terahertz and to operate in continuous mode. A method for operating semiconductor hole population inversion lasers with a closed cycle refrigerator.

  10. Airborne observations of far-infrared upwelling radiance in the Arctic

    Science.gov (United States)

    Libois, Quentin; Ivanescu, Liviu; Blanchet, Jean-Pierre; Schulz, Hannes; Bozem, Heiko; Leaitch, W. Richard; Burkart, Julia; Abbatt, Jonathan P. D.; Herber, Andreas B.; Aliabadi, Amir A.; Girard, Éric

    2016-12-01

    The first airborne measurements of the Far-InfraRed Radiometer (FIRR) were performed in April 2015 during the panarctic NETCARE campaign. Vertical profiles of spectral upwelling radiance in the range 8-50 µm were measured in clear and cloudy conditions from the surface up to 6 km. The clear sky profiles highlight the strong dependence of radiative fluxes to the temperature inversion typical of the Arctic. Measurements acquired for total column water vapour from 1.5 to 10.5 mm also underline the sensitivity of the far-infrared greenhouse effect to specific humidity. The cloudy cases show that optically thin ice clouds increase the cooling rate of the atmosphere, making them important pieces of the Arctic energy balance. One such cloud exhibited a very complex spatial structure, characterized by large horizontal heterogeneities at the kilometre scale. This emphasizes the difficulty of obtaining representative cloud observations with airborne measurements but also points out how challenging it is to model polar clouds radiative effects. These radiance measurements were successfully compared to simulations, suggesting that state-of-the-art radiative transfer models are suited to study the cold and dry Arctic atmosphere. Although FIRR in situ performances compare well to its laboratory performances, complementary simulations show that upgrading the FIRR radiometric resolution would greatly increase its sensitivity to atmospheric and cloud properties. Improved instrument temperature stability in flight and expected technological progress should help meet this objective. The campaign overall highlights the potential for airborne far-infrared radiometry and constitutes a relevant reference for future similar studies dedicated to the Arctic and for the development of spaceborne instruments.

  11. THE SPITZER ARCHIVAL FAR-INFRARED EXTRAGALACTIC SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Hanish, D. J.; Capak, P.; Teplitz, H. I.; Desai, V.; Armus, L.; Brinkworth, C.; Brooke, T.; Colbert, J.; Fadda, D.; Noriega-Crespo, A.; Paladini, R. [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 E California Blvd., Pasadena, CA 91125 (United States); Edwards, L. [Astronomy Department, 260 Whitney Avenue, Yale University, New Haven, CT 06511 (United States); Frayer, D. [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States); Huynh, M. [International Centre for Radio Astronomy Research, M468, University of Western Australia, Crawley, WA 6009 (Australia); Lacy, M. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Murphy, E. [The Observatories of the Carnegie Institution for Science, CA 91101 (United States); Scarlata, C. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Shenoy, S., E-mail: danish@alumni.caltech.edu [Space Science Division, NASA Ames Research Center, M/S 245-6, Moffett Field, CA 94035 (United States)

    2015-03-15

    We present the Spitzer Archival Far-InfraRed Extragalactic Survey (SAFIRES). This program produces refined mosaics and source lists for all far-infrared (FIR) extragalactic data taken during the more than six years of the cryogenic operation of the Spitzer Space Telescope. The SAFIRES products consist of FIR data in two wavelength bands (70 and 160 μm) across approximately 180 square degrees of sky, with source lists containing far-infrared fluxes for almost 40,000 extragalactic point sources. Thus, SAFIRES provides a large, robust archival far-infrared data set suitable for many scientific goals.

  12. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: III. Galactic far-infrared radiation

    Science.gov (United States)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2015-07-01

    Using the three-component spectral model describing the FIRAS average continuum spectra, the exact analytical expressions for thermodynamic and radiative functions of Galactic far-infrared radiation are obtained. The COBE FIRAS instrument data in the 0.15-2.88 THz frequency interval at the mean temperatures of T1 = 17.72 K, T2 = 14 K and T3 = 6.73 K are used for calculating the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, total emissivity, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume and pressure for the warm, intermediate-temperature and very cold components of the Galactic continuum spectra. The generalized Stefan-Boltzmann law for warm, intermediate-temperature and very cold components is constructed. The temperature dependence of each component is determined by the formula IS-B(T) = σ‧T6. This result is important when we construct the cosmological models of radiative transfer that can be applied inside the Galaxy. Within the framework of the three-component spectral model, the total number of photons in our Galaxy and the total radiation power (total luminosity) emitted from a surface of the Galaxy are calculated. Their values are NGtotal = 1.3780 × 1068 and IGtotal(T) = 1.0482 × 1036 W. Other radiative and thermodynamic properties of the Galactic far-infrared radiation (photon gas) of the Galaxy are calculated. The expressions for astrophysical parameters, such as the entropy density/Boltzmann constant and number density of the Galactic far-infrared photons are obtained. We assume that the obtained analytical expressions for thermodynamic and radiative functions may be useful for describing the continuum spectra of the far-infrared radiation for other galaxies.

  13. HERSCHEL FAR-INFRARED SPECTRAL-MAPPING OF ORION BN/KL OUTFLOWS: SPATIAL DISTRIBUTION OF EXCITED CO, H{sub 2}O, OH, O, AND C{sup +} IN SHOCKED GAS

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, Javier R.; Cernicharo, José; Cuadrado, Sara; Etxaluze, Mireya [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid (Spain); Chavarría, Luis [Centro de Astrobiología, CSIC-INTA, Ctra. de Torrejón a Ajalvir km 4, E-28850 Madrid (Spain); Neufeld, David A. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Vavrek, Roland [Herschel Science Center, ESA/ESAC, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid (Spain); Bergin, Edwin A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Encrenaz, Pierre [LERMA, UMR 8112 du CNRS, Observatoire de Paris, École Normale Supérieure, F-75014 Paris (France); Melnick, Gary J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 66, Cambridge, MA 02138 (United States); Polehampton, Edward, E-mail: jr.goicoechea@icmm.csic.es [RAL Space, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom)

    2015-01-20

    We present ∼2' × 2' spectral-maps of Orion Becklin-Neugebauer/Kleinmann-Low (BN/KL) outflows taken with Herschel at ∼12'' resolution. For the first time in the far-IR domain, we spatially resolve the emission associated with the bright H{sub 2} shocked regions ''Peak 1'' and ''Peak 2'' from that of the hot core and ambient cloud. We analyze the ∼54-310 μm spectra taken with the PACS and SPIRE spectrometers. More than 100 lines are detected, most of them rotationally excited lines of {sup 12}CO (up to J = 48-47), H{sub 2}O, OH, {sup 13}CO, and HCN. Peaks 1/2 are characterized by a very high L(CO)/L {sub FIR} ≈ 5 × 10{sup –3} ratio and a plethora of far-IR H{sub 2}O emission lines. The high-J CO and OH lines are a factor of ≈2 brighter toward Peak 1 whereas several excited H{sub 2}O lines are ≲50% brighter toward Peak 2. Most of the CO column density arises from T {sub k} ∼ 200-500 K gas that we associate with low-velocity shocks that fail to sputter grain ice mantles and show a maximum gas-phase H{sub 2}O/CO ≲ 10{sup –2} abundance ratio. In addition, the very excited CO (J > 35) and H{sub 2}O lines reveal a hotter gas component (T {sub k} ∼ 2500 K) from faster (v {sub S} > 25 km s{sup –1}) shocks that are able to sputter the frozen-out H{sub 2}O and lead to high H{sub 2}O/CO ≳ 1 abundance ratios. The H{sub 2}O and OH luminosities cannot be reproduced by shock models that assume high (undepleted) abundances of atomic oxygen in the preshock gas and/or neglect the presence of UV radiation in the postshock gas. Although massive outflows are a common feature in other massive star-forming cores, Orion BN/KL seems more peculiar because of its higher molecular luminosities and strong outflows caused by a recent explosive event.

  14. Far infrared spectrophotometry of Jupiter and Saturn

    Science.gov (United States)

    Erickson, E. F.; Goorvitch, D.; Simpson, J. P.; Strecker, D. W.

    1978-01-01

    Infrared spectral measurements of Mars, Jupiter, and Saturn were obtained from 100 to 470 kaysers and, by taking Mars as a calibration source, brightness temperatures of Jupiter and Saturn were determined with approximately 5 kayser resolution. Internal luminosities were determined from the data and are reported to be approximately 8 times 10 to the minus tenth power of the sun's luminosity for Jupiter and approximately 3.6 times 10 to the minus tenth power of the sun's luminosity for Saturn. Comparison of data with spectra predicted by models suggests the need for an opacity source in addition to gaseous hydrogen and ammonia to help explain Jupiter's observed spectrum in the vicinity of 250 kaysers.

  15. Far-infrared emission spectra of selected gas-phase PAHs: Spectroscopic fingerprints

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, K.; Guo, B.; Colarusso, P.; Bernath, P.F. [Univ. of Waterloo, Ontario (Canada)

    1996-10-25

    The emission spectra of the gaseous polycyclic aromatic hydrocarbons (PAHs) naphthalene, chrysene, and pyrene were recorded in the far-infrared (far-IR) region. The vibrational bands that lie in the far IR are unique for each PAH molecule and allow discrimination among the three PAH molecules. The far-IR PAH spectra, therefore, may prove useful in the assignment of unidentified spectral features from astronomical objects. 23 refs., 1 fig., 1 tab.

  16. Far-infrared surface emissivity and climate.

    Science.gov (United States)

    Feldman, Daniel R; Collins, William D; Pincus, Robert; Huang, Xianglei; Chen, Xiuhong

    2014-11-18

    Presently, there are no global measurement constraints on the surface emissivity at wavelengths longer than 15 μm, even though this surface property in this far-IR region has a direct impact on the outgoing longwave radiation (OLR) and infrared cooling rates where the column precipitable water vapor (PWV) is less than 1 mm. Such dry conditions are common for high-altitude and high-latitude locations, with the potential for modeled climate to be impacted by uncertain surface characteristics. This paper explores the sensitivity of instantaneous OLR and cooling rates to changes in far-IR surface emissivity and how this unconstrained property impacts climate model projections. At high latitudes and altitudes, a 0.05 change in emissivity due to mineralogy and snow grain size can cause a 1.8-2.0 W m(-2) difference in the instantaneous clear-sky OLR. A variety of radiative transfer techniques have been used to model the far-IR spectral emissivities of surface types defined by the International Geosphere-Biosphere Program. Incorporating these far-IR surface emissivities into the Representative Concentration Pathway (RCP) 8.5 scenario of the Community Earth System Model leads to discernible changes in the spatial patterns of surface temperature, OLR, and frozen surface extent. The model results differ at high latitudes by as much as 2°K, 10 W m(-2), and 15%, respectively, after only 25 y of integration. Additionally, the calculated difference in far-IR emissivity between ocean and sea ice of between 0.1 and 0.2, suggests the potential for a far-IR positive feedback for polar climate change.

  17. PACS photometry of the Herschel Reference Survey - far-infrared/submillimetre colours as tracers of dust properties in nearby galaxies

    Science.gov (United States)

    Cortese, L.; Fritz, J.; Bianchi, S.; Boselli, A.; Ciesla, L.; Bendo, G. J.; Boquien, M.; Roussel, H.; Baes, M.; Buat, V.; Clemens, M.; Cooray, A.; Cormier, D.; Davies, J. I.; De Looze, I.; Eales, S. A.; Fuller, C.; Hunt, L. K.; Madden, S.; Munoz-Mateos, J.; Pappalardo, C.; Pierini, D.; Rémy-Ruyer, A.; Sauvage, M.; di Serego Alighieri, S.; Smith, M. W. L.; Spinoglio, L.; Vaccari, M.; Vlahakis, C.

    2014-05-01

    We present Herschel/PACS 100 and 160 μm integrated photometry for the 323 galaxies in the Herschel Reference Survey (HRS), a K-band, volume-limited sample of galaxies in the local Universe. Once combined with the Herschel/SPIRE observations already available, these data make the HRS the largest representative sample of nearby galaxies with homogeneous coverage across the 100-500 μm wavelength range. In this paper, we take advantage of this unique data set to investigate the properties and shape of the far-infrared/submillimetre spectral energy distribution in nearby galaxies. We show that, in the stellar mass range covered by the HRS (8 ≲ log (M*/M⊙) ≲ 12), the far-infrared/submillimetre colours are inconsistent with a single modified blackbody having the same dust emissivity index β for all galaxies. In particular, either β decreases or multiple temperature components are needed, when moving from metal-rich/gas-poor to metal-poor/gas-rich galaxies. We thus investigate how the dust temperature and mass obtained from a single modified blackbody depend on the assumptions made on β. We show that, while the correlations between dust temperature, galaxy structure and star formation rate are strongly model dependent, the dust mass scaling relations are much more reliable, and variations of β only change the strength of the observed trends.

  18. Infrared-faint radio sources remain undetected at far-infrared wavelengths. Deep photometric observations using the Herschel Space Observatory

    CERN Document Server

    Herzog, Andreas; Middelberg, Enno; Spitler, Lee R; Leipski, Christian; Parker, Quentin A

    2015-01-01

    Showing 1.4 GHz flux densities in the range of a few to a few tens of mJy, infrared-faint radio sources (IFRS) are a type of galaxy characterised by faint or absent near-infrared counterparts and consequently extreme radio-to-infrared flux density ratios up to several thousand. Recent studies showed that IFRS are radio-loud active galactic nuclei (AGNs) at redshifts >=2. This work explores the far-infrared emission of IFRS, providing crucial information on the star forming and AGN activity of IFRS and on the potential link between IFRS and high-redshift radio galaxies (HzRGs). A sample of six IFRS was observed with the Herschel Space Observatory between 100 um and 500 um. Using these results, we constrained the nature of IFRS by modelling their broad-band spectral energy distribution (SED). Furthermore, we set an upper limit on their infrared SED and decomposed their emission into contributions from an AGN and from star forming activity. All six observed IFRS were undetected in all five Herschel far-infrared ...

  19. A Far-Infrared FEL for the Radiation Source ELBE

    CERN Document Server

    Seidel, W; Lehnert, U; Michel, P; Schlenk, R; Willkommen, U; Wohlfarth, D; Wünsch, R

    2005-01-01

    After successfully commissioning the mid-infrared FEL (U27) and adjoining a second accelerator unit (up to 35 MeV) at ELBE we have modified our plan how to produce radiation in the far infrared.To ensure the continuous variation of the wavelength up to 150 microns we want to complement the U27 undulator by a permanent magnet undulator with a period of 100 mm (U100). The minimum gap of 24 mm and the hybrid construction consisting of Sm/Co magnets and soft iron poles ensures sufficient radiation resistance and allows rms undulator parameters up to 2.7. The large field variation allows us to cover the whole wavelength range by only two different electron energies (e.g. 20 and 35 MeV). To reduce the transverse beam size we use a partial waveguide which is 10 mm high and wide enough to allow free propagation in horizontal direction. It spans from the last quadrupole in front of the undulator up to the downstream mirror and is somewhat longer than 8 m. To minimize the coupling losses between free propagation and th...

  20. The $AKARI$ Far-Infrared All-Sky Survey Maps

    CERN Document Server

    Doi, Yasuo; Ootsubo, Takafumi; Arimatsu, Ko; Tanaka, Masahiro; Kitamura, Yoshimi; Kawada, Mitsunobu; Matsuura, Shuji; Nakagawa, Takao; Morishima, Takahiro; Hattori, Makoto; Komugi, Shinya; White, Glenn J; Ikeda, Norio; Kato, Daisuke; Chinone, Yuji; Etxaluze, Mireya; Figueredo, Elysandra

    2015-01-01

    We present a far-infrared all-sky atlas from a sensitive all-sky survey using the Japanese $AKARI$ satellite. The survey covers $> 99$% of the sky in four photometric bands centred at 65 $\\mu$m, 90 $\\mu$m, 140 $\\mu$m, and 160 $\\mu$m with spatial resolutions ranging from 1 to 1.5 arcmin. These data provide crucial information for the investigation and characterisation of the properties of dusty material in the Interstellar Medium (ISM), since significant portion of its energy is emitted between $\\sim$50 and 200 $\\mu$m. The large-scale distribution of interstellar clouds, their thermal dust temperatures and column densities, can be investigated with the improved spatial resolution compared to earlier all-sky survey observations. In addition to the point source distribution, the large-scale distribution of ISM cirrus emission, and its filamentary structure, are well traced. We have made the first public release of the full-sky data to provide a legacy data set for use by the astronomical community.

  1. The AKARI far-infrared all-sky survey maps

    Science.gov (United States)

    Doi, Yasuo; Takita, Satoshi; Ootsubo, Takafumi; Arimatsu, Ko; Tanaka, Masahiro; Kitamura, Yoshimi; Kawada, Mitsunobu; Matsuura, Shuji; Nakagawa, Takao; Morishima, Takahiro; Hattori, Makoto; Komugi, Shinya; White, Glenn J.; Ikeda, Norio; Kato, Daisuke; Chinone, Yuji; Etxaluze, Mireya; Cypriano, Elysandra F.

    2015-06-01

    We present a far-infrared all-sky atlas from a sensitive all-sky survey using the Japanese AKARI satellite. The survey covers > 99% of the sky in four photometric bands centred at 65 μm, 90 μm, 140 μm, and 160 μm, with spatial resolutions ranging from 1' to 1{^''.}5. These data provide crucial information on the investigation and characterisation of the properties of dusty material in the interstellar medium (ISM), since a significant portion of its energy is emitted between ˜ 50 and 200 μm. The large-scale distribution of interstellar clouds, their thermal dust temperatures, and their column densities can be investigated with the improved spatial resolution compared to earlier all-sky survey observations. In addition to the point source distribution, the large-scale distribution of ISM cirrus emission, and its filamentary structure, are well traced. We have made the first public release of the full-sky data to provide a legacy data set for use in the astronomical community.

  2. AKARI Far-Infrared All-Sky Survey Maps

    CERN Document Server

    Doi, Yasuo; Kawada, Mitsunobu; Takita, Satoshi; Arimatsu, Ko; Ikeda, Norio; Kato, Daisuke; Kitamura, Yoshimi; Nakagawa, Takao; Ootsubo, Takafumi; Morishima, Takahiro; Hattori, Makoto; Tanaka, Masahiro; White, Glenn J; Etxaluze, Mireya; Shibai, Hiroshi

    2012-01-01

    Far-infrared observations provide crucial data for the investigation and characterisation of the properties of dusty material in the Interstellar Medium (ISM), since most of its energy is emitted between ~100 and 200 um. We present the first all-sky image from a sensitive all-sky survey using the Japanese AKARI satellite, in the wavelength range 50 -- 180 um. Covering >99% of the sky in four photometric bands with four filters centred at 65 um, 90 um, 140 um, and 160 um wavelengths, this achieved spatial resolutions from 1 to 2 arcmin and a detection limit of <10 MJy sr-1, with absolute and relative photometric accuracies of <20%. All-sky images of the Galactic dust continuum emission enable astronomers to map the large-scale distribution of the diffuse ISM cirrus, to study its thermal dust temperature, emissivity and column density, and to measure the interaction of the Galactic radiation field and embedded objects with the surrounding ISM. In addition to the point source population of stars, protostar...

  3. Far-Infrared Spectroscopy of Anti-Vinyl Alcohol

    Science.gov (United States)

    Raston, Paul; Bunn, Hayley

    2016-06-01

    Vinyl alcohol can exist in two rotameric forms, known as syn- and anti- vinyl alcohol, where syn is the most stable. Both rotamers have been observed in the interstellar medium towards Sagittarius B2(N) making them of particular astrophysical importance. Vinyl alcohol has been subject to various spectroscopic investigations, however, the anti rotamer has only been obsvered in the microwave region. We report the high resolution (0.001 wn) FTIR spectrum of anti-vinyl alcohol collected at the infrared beamline facility of the Australian Synchrotron. Vinyl alcohol was produced via the pyrolysis of 2-chloroethanol at 900°C, and its far infrared spectrum reveals the presence of the strong νb{15} fundamental and hot band of anti-vinyl alcohol. Rotational and centrifugal distortion constants of this higher energy rotamer have since been determined for the νb{15} and 2νb{15} states, and the ground state constants have been refined. B. E. Turner, A. J. Apponi, ApJ 561, 207 (2001) M. Rodler, J. Mol. Spec. 114, 23 (1985) D-L Joo, et al., J. Mol. Spec. 197, 68 (1999)

  4. FIRI - a Far-Infrared Interferometer

    CERN Document Server

    Helmich, Frank

    2007-01-01

    Half of the energy ever emitted by stars and accreting objects comes to us in the FIR waveband and has yet to be properly explored. We propose a powerful Far-InfraRed Interferometer mission, FIRI, to carry out high-resolution imaging spectroscopy in the FIR. This key observational capability is essential to reveal how gas and dust evolve into stars and planets, how the first luminous objects in the Universe ignited, how galaxies formed, and when super-massive black holes grew. FIRI will disentangle the cosmic histories of star formation and accretion onto black holes and will trace the assembly and evolution of quiescent galaxies like our Milky Way. Perhaps most importantly, FIRI will observe all stages of planetary system formation and recognise Earth-like planets that may harbour life, via its ability to image the dust structures in planetary systems. It will thus address directly questions fundamental to our understanding of how the Universe has developed and evolved - the very questions posed by ESA's Cos...

  5. Unidirectionality of an optically pumped far infrared ring laser

    Science.gov (United States)

    Matsushima, Kyoji; Higashida, Noriyoshi; Sokabe, Noburu; Ariyasu, Tomio

    1995-02-01

    An experimental and theoretical investigation has been made on the unidirectional operation of an optically pumped far infrared ring laser. A ring laser operating on the 119 μm line of CH 3OH experiences reversal of output direction in either case of (a) the pump frequency being tuned across the line center of the infrared pump transition or (b) the fir cavity being tuned across the far infrared line center. A model based on two-mode laser theory predicts the output directionality of the optically pumped fir ring laser.

  6. Far-infrared quantum cascade lasers operating in AlAs phonon Reststrahlen band

    CERN Document Server

    Ohtani, K; Süess, M J; Faist, J; Andrews, A M; Zederbauer, T; Detz, H; Schrenk, W; Strasser, G

    2016-01-01

    We report on the operation of a double metal waveguide far-infrared quantum cascade laser emitting at 28 $\\mu$m, corresponding to the AlAs-like phonon Reststrahlen band. To avoid absorption by AlAs-like optical phonons, the Al-free group-V alloy GaAs$_{0.51}$Sb$_{0.49}$ is used as a barrier layer in the bound-to-continuum based active region. Lasing occurs at a wavelength of 28.3 $\\mu$m, which is the longest wavelength among the quantum cascade lasers operating from mid-infrared to far-infrared. The threshold current density at 50 K is 5.5 kA/cm$^{2}$ and maximum operation temperature is 175 K. We also discuss the feasibility that operation wavelength cover the whole spectral range bridging between mid-infrared and terahertz by choosing suited group III-V materials.

  7. The nuclear and integrated far-infrared emission of nearby Seyfert galaxies

    CERN Document Server

    García-González, J; Hernán-Caballero, A; Pereira-Santaella, M; Ramos-Almeida, C; Pulido, J A Acosta; Díaz-Santos, T; Esquej, P; González-Martín, O; Ichikawa, K; López-Rodríguez, E; Povic, M; Roche, P F; Sánchez-Portal, M

    2016-01-01

    We present far-infrared (FIR) $70-500\\,\\mu$m imaging observations obtained with Herschel/PACS and SPIRE of 33 nearby (median distance of 30 Mpc) Seyfert galaxies from the Revised Shapley-Ames (RSA) catalogue. We obtain the FIR nuclear ($r=1\\,$kpc and $r=2\\,$kpc) and integrated spectral energy distributions (SEDs). We estimate the unresolved nuclear emission at 70 $\\mu$m and we fit the nuclear and integrated FIR SEDs with a grey body model. We find that the integrated FIR emission of the RSA Seyferts in our sample is dominated by emission from the host galaxy, with dust properties similar to those of normal galaxies (non AGN). We use four criteria to select galaxies whose nuclear $70\\,\\mu$m emission has a significant AGN contribution: (1) elevated 70/160 $\\mu$m flux ratios, (2)spatially resolved, high dust temperature gradient, (3) $70\\,\\mu$m excess emission with respect to the fit of the FIR SEDs with a grey body, and (4) excess of nuclear SFR obtained from $70\\,\\mu$m over SFR from mid-infrared indicators. 16...

  8. The far-infrared emission of the radio-loud quasar 3C318

    CERN Document Server

    Podigachoski, P; Peletier, R F; Steendam, S

    2016-01-01

    3C318, a radio-loud quasar at z=1.574, is a subgalactic-sized radio source, and a good test-bed for the interplay between black hole and galaxy growth in the high-z Universe. Based on its IRAS, ISO, and SCUBA detections, it has long been considered as one of the most intrinsically luminous (L$_{\\mathrm{IR}}$ > 10$^{13}$ L$_{\\odot}$) infrared sources in the Universe. Recent far-infrared data from the Herschel Space Observatory reveal that most of the flux associated with 3C318 measured with earlier instruments in fact comes from a bright nearby source. Optical imaging and spectroscopy show that this infrared-bright source is a strongly star-forming pair of interacting galaxies at z=0.35. Adding existing Spitzer and SDSS photometry, we perform a spectral energy distribution analysis of the pair, and find that it has a combined infrared luminosity of L$_{\\mathrm{IR}}$ = 1.5 $\\times$ 10$^{12}$ L$_{\\odot}$, comparable to other intermediate-redshift ultra-luminous infrared galaxies studied with Herschel. Isolating ...

  9. Vibrational excitations of proteins and their hydration water in the far-infrared range

    Energy Technology Data Exchange (ETDEWEB)

    Paciaroni, A., E-mail: alessandro.paciaroni@fisica.unipg.it [Dipartimento di Fisica, Universita’ degli Studi di Perugia, Via Pascoli, I-06123 Perugia (Italy); Conti Nibali, V. [Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, 44780 Bochum (Germany); Orecchini, A. [Dipartimento di Fisica, Universita’ degli Studi di Perugia, Via Pascoli, I-06123 Perugia (Italy); Institut Laue Langevin, 6 rue J. Horowitz, F-38042 Grenoble (France); Petrillo, C. [Dipartimento di Fisica, Universita’ degli Studi di Perugia, Via Pascoli, I-06123 Perugia (Italy); Haertlein, M.; Moulin, M. [Institut Laue Langevin, 6 rue J. Horowitz, F-38042 Grenoble (France); Tarek, M. [UMR Structure et Réactivité des Systèmes Moléculaires Complexes, Nancy-University, CNRS (France); D’Angelo, G. [Dipartimento di Fisica, Universita’ degli Studi di Messina, Viale F. Stagno d’Alcontres 31, I-98166 Messina (Italy); Sacchetti, F. [Dipartimento di Fisica, Universita’ degli Studi di Perugia, Via Pascoli, I-06123 Perugia (Italy)

    2013-10-16

    Highlights: • We characterize the vibrations of proteins and hydration water in far-infrared range. • Isotopic contrast is used to highlight protein or water component. • MD simulations help understanding vibrational bands. • The inelastic behavior of proteins is quite independent on the solvent. • Protein hydration water vibrational behavior is similar to amorphous ice. - Abstract: Incoherent neutron scattering has been used to single out the vibrational contribution from maltose binding protein (MBP) and its hydration water in the energy range 1 meV–80 meV. The vibrational density of states from both protein and hydration water have been investigated by measuring respectively dry and D{sub 2}O-hydrated isotopically natural MBP and dry and H{sub 2}O-hydrated perdeuterated MBP. Molecular dynamics simulations done on the same system allow us to attribute the protein inelastic features. The inelastic behavior of the biomolecule seems to be largely independent on the presence of solvent. Conversely, protein hydration water exhibits remarkable differences with respect to hexagonal ice in the whole spectral range, with clear similarities to amorphous phases of ice.

  10. The spatial distribution of the far-infrared emission in NGC 253

    CERN Document Server

    Melo, V P; Acosta-Pulido, J A; Muñoz-Tunón, C; Rodríguez-Espinosa, J M

    2002-01-01

    We study the far-infrared emission properties of the nearby starburst galaxy NGC 253 based on IRAS maps and an ISOPHOT map at 180 microns. Based on the analysis of the light profiles, we have been able to identify three main structural components: an unresolved nuclear component, an exponential disk, and a kiloparsec scale bar.In addition, we also found a ring structure at the end of the bar that is particularly conspicuous at 12 microns. The Spectral Energy Distribution (SED) of each morphological component has been modeled as thermal dust emission at different temperatures. The unresolved nuclear component is dominated by cold dust emission (T ~ 50 K), whereas the disk emission is dominated by very cold dust (T ~ 16 K) plus a contribution from cold dust (T ~ 55 K). The bar emission corresponds mainly to cold dust (T ~ 23 K) plus a warm component (T ~ 148 K). We detect an extension of the disk emission due to very cold dust, which contributes a large fraction (94%) of the total dust mass of the galaxy. The e...

  11. The RMS Survey: Far-Infrared Photometry of Young Massive Stars

    CERN Document Server

    Mottram, J C; Lumsden, S L; Oudmaijer, R D; Urquhart, J S; Meade, M R; Moore, T J T; Stead, J J

    2009-01-01

    Context: The Red MSX Source (RMS) survey is a multi-wavelength campaign of follow-up observations of a colour-selected sample of candidate massive young stellar objects (MYSOs) in the galactic plane. This survey is returning the largest well-selected sample of MYSOs to date, while identifying other dust contaminant sources with similar mid-infrared colours including a large number of new ultra-compact (UC)HII regions. Aims:To measure the far-infrared (IR) flux, which lies near the peak of the spectral energy distribution (SED) of MYSOs and UCHII regions, so that, together with distance information, the luminosity of these sources can be obtained. Methods:Less than 50% of RMS sources are associated with IRAS point sources with detections at 60 micron and 100 micron, though the vast majority are visible in Spitzer MIPSGAL or IRAS Galaxy Atlas (IGA) images. However, standard aperture photometry is not appropriate for these data due to crowding of sources and strong spatially variable far-IR background emission i...

  12. A study of Sn addition on bonding arrangement of Se-Te alloys using far infrared transmission spectroscopy

    Science.gov (United States)

    Kumar, Rajneesh; Sharma, Parikshit; Katyal, S. C.; Sharma, Pankaj; Rangra, V. S.

    2011-07-01

    Far infrared transmission spectra of Se92Te8-xSnx (x = 0, 1, 2, 3, 4, 5) glassy alloys are obtained in the spectral range 50-600 cm-1 at room temperature. The results are interpreted in terms of the vibrations of the isolated molecular units in such a way so as to preserve fourfold and twofold coordination for Sn and chalcogen atoms (Se,Te), respectively. With the addition of Sn, Far-IR spectra shift toward high frequency side and some new bands start appearing. Sn atoms appear to substitute for the selenium atoms in the outrigger sites due to large bond formation probability. Theoretical calculations of bond energy, relative probability of bond formation, force constant, and wave number were also made to justify the result.

  13. A study of Sn addition on bonding arrangement of Se-Te alloys using far infrared transmission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rajneesh; Rangra, V. S. [Department of Physics, Himachal Pradesh University, Summer-Hill, Shimla, H.P. - 171005 (India); Sharma, Parikshit [Department of Physics, Sri Sai University, Palampur, HP (India); Katyal, S. C. [Department of Physics, Jaypee Institute of Information Technology, Noida, U.P. (India); Sharma, Pankaj [Department of Physics, Jaypee University of Information Technology, Waknghat, Solan, H.P. 173215 (India)

    2011-07-01

    Far infrared transmission spectra of Se{sub 92}Te{sub 8-x}Sn{sub x} (x = 0, 1, 2, 3, 4, 5) glassy alloys are obtained in the spectral range 50-600 cm{sup -1} at room temperature. The results are interpreted in terms of the vibrations of the isolated molecular units in such a way so as to preserve fourfold and twofold coordination for Sn and chalcogen atoms (Se,Te), respectively. With the addition of Sn, Far-IR spectra shift toward high frequency side and some new bands start appearing. Sn atoms appear to substitute for the selenium atoms in the outrigger sites due to large bond formation probability. Theoretical calculations of bond energy, relative probability of bond formation, force constant, and wave number were also made to justify the result.

  14. Far infrared polarimeter with very low instrumental polarization

    CERN Document Server

    Battistelli, E S; Lamagna, L; Maoli, R; Melchiorri, F; Palladino, E; Savini, G; Mauskopf, P D; Orlando, A E

    2002-01-01

    After a short analysis of the main problems involved in the construction of a Far Infrared polarimeter with very low instrumental noise, we describe the instrument that will be employed at MITO telescope to search for calibration sources and investigate polarization near the CMB anisotropy peaks in the next campaign (Winter 2002-03).

  15. OPTICAL DIFFERENCE FREQUENCY GENERATION OF FAR INFRARED RADIATION

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J.R.

    1977-07-01

    Three investigations of difference frequency generation (DFG) of far-infrared radiation by optical mixing are described: a theory of DFG by monochromatic, focused Gaussian pump laser beams, a theory of DFG by a picosecond pump laser pulse, and an experiment using ruby-pumped dye lasers. First, the theory of far-infrared generation by optical mixing of monochromatic, focused Gaussian beams in a uniaxial crystal is developed, taking into account the effects of diffraction, absorption, double refraction, and multiple reflections and total reflection at the boundary surfaces. (Reflection and transmission coefficients of a uniaxial crystal slab are derived by a new matrix technique.) Results of numerical calculations are presented. Focusing the pump beams appreciably enhances the far-infrared output despite the strong far-infrared diffraction. In a 1-cm long crystal, the optimum focal spot size is approximately equal to or smaller than the far-infrared wavelength for output frequencies less than 100 cm{sup -1}. Double refraction of the pump beams is relatively unimportant. Both far-infrared absorption and boundary reflections have major effects on the far-infrared output and its angular distribution. The former is often the factor which limits the output power. We show that a simple model treating the nonlinear polarization as a constant lie-radius Gaussian distribution of radiating dipoles adequately describes the effect of pump-beam focusing. We also compare the results of our calculations with those for second-harmonic generation. Second, a theoretical calculation of far-infrared power spectra generated by picosecond pulses in a nonlinear crystal is developed. The results are illustrated with two practical examples: LiNbO{sub 3} slabs oriented for rectification of the optical e-ray and for beating of the optical o-ray with the optical e-ray. The former is phase matched at 0 cm{sup -1}; the latter, at both the forward-(FCPM) and backward-collinear phase

  16. A Far-infrared Undulator for Coherent Synchrotron Radiation and Free Electron Laser at Tohoku University

    Science.gov (United States)

    Hama, Hiroyuki; Hinode, Fujio; Kawai, Masayuki; Nanbu, Kenichi; Miyahara, Fusashi; Yasuda, Mafuyu

    2010-06-01

    In order to develop an intense far-infrared radiation source, a high quality electron beam has been studied at Tohoku University, Sendai. The bunch length of the beam expected is very much shorter than terahertz (THz) wavelength, so that coherent spontaneous emission of synchrotron radiation will be a promising high brilliant far-infrared source. An undulator consisting of permanent magnets has been designed in which optional free electron laser (FEL) will be operated in free space mode. Consequently the minimum gap of the undulator is decided to be 54 mm for 0.36 mm radiation to avoid diffraction loss, and then the period length of 10 cm is employed. The undulator may cover a wavelength range from 0.18 to 0.36 mm with the beam energy of 17 MeV. Property of coherent THz radiation from the undulator and possibility of novel pre-bunched THz FEL is discussed.

  17. On the nitrogen-induced far-infrared absorption spectra

    Science.gov (United States)

    Dore, P.; Filabozzi, A.

    1987-01-01

    The rototranslational absorption spectrum of gaseous N2 is analyzed, considering quadrupolar and hexadecapolar induction mechanisms. The available experimental data are accounted for by using a line-shape analysis in which empirical profiles describe the single-line translational profiles. Thus, a simple procedure is derived that allows the prediction of the N2 spectrum at any temperature. On the basis of the results obtained for the pure gas, a procedure to compute the far-infrared spectrum of the N2-Ar gaseous mixture is also proposed. The good agreement between computed and experimental N2-Ar data indicates that it is possible to predict the far-infrared absorption induced by N2 on the isotropic polarizability of any interacting partner.

  18. Stacked Metal Silicide/Silicon Far-Infrared Detectors

    Science.gov (United States)

    Maserjian, Joseph

    1988-01-01

    Selective doping of silicon in proposed metal silicide/silicon Schottky-barrier infrared photodetector increases maximum detectable wavelength. Stacking layers to form multiple Schottky barriers increases quantum efficiency of detector. Detectors of new type enhance capabilities of far-infrared imaging arrays. Grows by molecular-beam epitaxy on silicon waferscontaining very-large-scale integrated circuits. Imaging arrays of detectors made in monolithic units with image-preprocessing circuitry.

  19. Portable He-3 detector cryostat for the far infrared

    Science.gov (United States)

    Radostitz, J. V.; Nolt, I. G.; Kittel, P.; Donnelly, R. J.

    1978-01-01

    The design of a portable He-3 cryostat for far infrared detection applications is described, with a cutaway drawing of the cryostat, including bolometer and cooled optics, provided. Consideration is given to the selection and testing of various bolometer materials, including Ge:Ga and Ge:InSb; the resistance-temperature coefficients of the materials examined are presented. The absolute flux calibration of the detector system using a new temperature-modulated cold source method is described.

  20. Far Infrared Optical Spectroscopy of Alkali Halide-Polymer Composites

    Science.gov (United States)

    McWhirter, J. T.; Broderick, S. D.; Rodriguez, G. A.

    1998-03-01

    Composite samples of small (dimension polytetrafluoroethylene) have been prepared. The far infrared optical spectra of these samples are presented, spanning a temperature range of 300 to thermal expansion, using published values for the mode Gruneisen parameter and the temperature dependence of the lattice thermal coefficient. In contrast, the linewidth (phonon lifetime) of the composite samples is roughly twice as large as that observed for thin film and bulk crystals, and has a much stronger temperature dependence as well.

  1. Radio Through X-ray Spectral Energy Distributions of 38 Broad Absorption Line Quasars

    CERN Document Server

    Gallagher, S C; Brandt, W N; Egami, E; Hines, D C; Priddey, R S

    2007-01-01

    We have compiled the largest sample of multiwavelength spectral energy distributions (SEDs) of Broad Absorption Line (BAL) quasars to date, from the radio to the X-ray. We present new Spitzer MIPS (24, 70, and 160 micron) observations of 38 BAL quasars in addition to data from the literature and public archives. In general, the mid-infrared properties of BAL quasars are consistent with those of non-BAL quasars of comparable luminosity. In particular, the optical-to-mid-infrared luminosity ratios of the two populations are indistinguishable. We also measure or place upper limits on the contribution of star formation to the far-infrared power. Of 22 (57%) upper limits, seven quasars have sufficiently sensitive constraints to conclude that star formation likely contributes little (<20%) to their far-infrared power. The 17 BAL quasars (45%) with detected excess far-infrared emission likely host hyperluminous starbursts with L_fir,SF=10^{13-14} L_sun. Mid-infrared through X-ray composite BAL quasar SEDs are pre...

  2. Far infrared and low frequency gas phase Raman spectra and conformational stability of the 1-halopropanes

    Science.gov (United States)

    Durig, J. R.; Godbey, S. E.; Sullivan, J. F.

    1984-06-01

    The far infrared (375-50 cm-1) and low frequency Raman (400-70 cm-1) spectra of the gaseous 1-halopropanes CH3CH2CH2F, CH3CH2CH2Cl, and CH3CH2CH2Br have been recorded and both the methyl and asymmetric torsional modes have been observed and assigned for both the gauche and trans conformers for all of these molecules. The asymmetric torsions for each molecule have several observed excited states which fall on the low frequency side of the fundamental. The asymmetric torsional potential functions have been calculated and, from these potential functions, the enthalpy differences between the high energy trans and low energy gauche conformers have been determined to be 122±10 cm-1 for the fluoride, 127±10 cm-1 for the chloride, and 37±10 cm-1 for the bromide. The trans and gauche methyl torsions have also been observed and assigned for the three 1-halopropanes. The resulting barriers in cm-1 are: 936±4 (trans), 986±9 (gauche) for 1-fluoropropane; 929±2 (trans), 1080±3 (gauche) for 1-chloropropane; and 841 (trans), 1016±8 (gauche) for 1-bromopropane. A complete vibrational assignment has also been made for the 1-fluoropropane molecule and, from the spectral data for the solid, it appears that there are two or more molecules per primitive cell. Attempts to obtain experimental values for the enthalpy differences in the gas phase were made and these results, as well as the determined potential functions, are discussed in relation to previous studies.

  3. Dust models post-Planck: constraining the far-infrared opacity of dust in the diffuse interstellar medium

    Science.gov (United States)

    Fanciullo, L.; Guillet, V.; Aniano, G.; Jones, A. P.; Ysard, N.; Miville-Deschênes, M.-A.; Boulanger, F.; Köhler, M.

    2015-08-01

    Aims: We compare the performance of several dust models in reproducing the dust spectral energy distribution (SED) per unit extinction in the diffuse interstellar medium (ISM). We use our results to constrain the variability of the optical properties of big grains in the diffuse ISM, as published by the Planck collaboration. Methods: We use two different techniques to compare the predictions of dust models to data from the Planck HFI, IRAS, and SDSS surveys. First, we fit the far-infrared emission spectrum to recover the dust extinction and the intensity of the interstellar radiation field (ISRF). Second, we infer the ISRF intensity from the total power emitted by dust per unit extinction, and then predict the emission spectrum. In both cases, we test the ability of the models to reproduce dust emission and extinction at the same time. Results: We identify two issues. Not all models can reproduce the average dust emission per unit extinction: there are differences of up to a factor ~2 between models, and the best accord between model and observation is obtained with the more emissive grains derived from recent laboratory data on silicates and amorphous carbons. All models fail to reproduce the variations in the emission per unit extinction if the only variable parameter is the ISRF intensity: this confirms that the optical properties of dust are indeed variable in the diffuse ISM. Conclusions: Diffuse ISM observations are consistent with a scenario where both ISRF intensity and dust optical properties vary. The ratio of the far-infrared opacity to the V band extinction cross-section presents variations of the order of ~20% (40-50% in extreme cases), while ISRF intensity varies by ~30% (~60% in extreme cases). This must be accounted for in future modelling. Appendices are available in electronic form at http://www.aanda.org

  4. Invited article: An integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument.

    Science.gov (United States)

    Kühne, P; Herzinger, C M; Schubert, M; Woollam, J A; Hofmann, T

    2014-07-01

    We report on the development of the first integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument, covering an ultra wide spectral range from 3 cm(-1) to 7000 cm(-1) (0.1-210 THz or 0.4-870 meV). The instrument comprises four sub-systems, where the magneto-cryostat-transfer sub-system enables the usage of the magneto-cryostat sub-system with the mid-infrared ellipsometer sub-system, and the far-infrared/terahertz ellipsometer sub-system. Both ellipsometer sub-systems can be used as variable angle-of-incidence spectroscopic ellipsometers in reflection or transmission mode, and are equipped with multiple light sources and detectors. The ellipsometer sub-systems are operated in polarizer-sample-rotating-analyzer configuration granting access to the upper left 3 × 3 block of the normalized 4 × 4 Mueller matrix. The closed cycle magneto-cryostat sub-system provides sample temperatures between room temperature and 1.4 K and magnetic fields up to 8 T, enabling the detection of transverse and longitudinal magnetic field-induced birefringence. We discuss theoretical background and practical realization of the integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument, as well as acquisition of optical Hall effect data and the corresponding model analysis procedures. Exemplarily, epitaxial graphene grown on 6H-SiC, a tellurium doped bulk GaAs sample and an AlGaN/GaN high electron mobility transistor structure are investigated. The selected experimental datasets display the full spectral, magnetic field and temperature range of the instrument and demonstrate data analysis strategies. Effects from free charge carriers in two dimensional confinement and in a volume material, as well as quantum mechanical effects (inter-Landau-level transitions) are observed and discussed exemplarily.

  5. The Herschel Orion Protostar Survey: Constraining Protostellar Models with Near- to Far-Infrared Observations

    Science.gov (United States)

    Furlan, Elise; Ali, Babar; Fischer, Will; Tobin, John; Stutz, Amy; Megeath, Tom; Allen, Lori; HOPS Team

    2013-07-01

    During the protostellar stage of star formation, a young star is surrounded by a large infalling envelope of dust and gas; the material falls onto a circumstellar disk and is eventually accreted by the central star. The dust in the disk and envelope emits prominently at mid- to far-infrared wavelengths; at 10 micron, absorption by small silicate grains typically causes a broad absorption feature. By modeling the near- to far-IR spectral energy distributions (SEDs) of protostars, properties of their disks and envelopes can be derived. As part of the Herschel Orion Protostar Survey (HOPS; PI: S. T. Megeath), we have observed a large sample of protostars in the Orion star-forming complex at 70 and 160 micron with the PACS instrument on the Herschel Space Observatory. For most objects, we also have photometry in the near-IR (2MASS), mid-IR (Spitzer/ IRAC and MIPS), at 100 micron (PACS data from the Gould Belt Survey), sub-mm (APEX/SABOCA and LABOCA), and mid-infrared spectra (Spitzer/IRS). For the interpretation of the SEDs, we have constructed a large grid of protostellar models using a Monte Carlo radiative transfer code. Here we present our SED fitting techniques to determine the best-fit model for each object. We show the importance of including IRS spectra with appropriate weights, in addition to the constraints provided by the PACS measurements, which probe the peak of the SED. The 10 micron silicate absorption feature and the mid- to far-IR SED slope provide key constraints for the inclination angle of the object and its envelope density, with a deep absorption feature and steep SED slope for the most embedded and highly inclined objects. We show a few examples that illustrate our SED fitting method and present some preliminary results from our fits.

  6. A Broadband Micro-machined Far-Infrared Absorber

    CERN Document Server

    Wollack, Edward J; Jhabvala, Christine A; Miller, Kevin H; Quijada, Manuel A

    2016-01-01

    The experimental investigation of a broadband far-infrared meta-material absorber is described. The observed absorptance is $>\\,0.95$ from ${\\rm 1-20\\,THz}$ (${\\rm 300-15\\,\\mu m}$) over a temperature range spanning ${\\rm 5-300\\,K}$. The meta-material, realized from an array of tapers ${\\rm \\approx 100\\,\\mu m}$ in length, is largely insensitive to the detailed geometry of these elements and is cryogenically compatible with silicon-based micro-machined technologies. The electromagnetic response is in general agreement with a physically motivated transmission line model.

  7. THE FAR-INFRARED ROTATIONAL SPECTRUM OF ETHYLENE OXIDE

    Energy Technology Data Exchange (ETDEWEB)

    Medcraft, Chris; Thompson, Christopher D.; McNaughton, Don [School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800 (Australia); Robertson, Evan G. [Department of Chemistry, La Trobe Institute of Molecular Sciences, La Trobe University, Bundoora, Victoria 3086 (Australia); Appadoo, Dominique R. T., E-mail: donald.mcnaughton@monash.edu [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia)

    2012-07-01

    High-resolution FTIR spectra of ethylene oxide have been measured in the far-infrared region using synchrotron radiation. A total of 1182 lines between 15 and 73 cm{sup -1} were assigned, with J{sub max} = 64, expanding upon previous studies that had recorded spectra up to 12 cm{sup -1}, J{sub max} = 49. All available data were co-fitted to provide greatly imp- roved rotational constants for the ground vibrational state that are capable of predicting transitions up to 73 cm{sup -1}.

  8. Far-Infrared Absorption of PbSe Nanorods

    KAUST Repository

    Hyun, Byung-Ryool

    2011-07-13

    Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical electrostatic model, which is based on the dielectric function of bulk PbSe but without any free-carrier contribution. Good agreement between the measured and calculated spectra indicates that resonances in the local field factors underlie the measured spectra. © 2011 American Chemical Society.

  9. A broadband micro-machined far-infrared absorber

    Science.gov (United States)

    Wollack, E. J.; Datesman, A. M.; Jhabvala, C. A.; Miller, K. H.; Quijada, M. A.

    2016-05-01

    The experimental investigation of a broadband far-infrared meta-material absorber is described. The observed absorptance is >0.95 from 1 to 20 THz (300-15 μm) over a temperature range spanning 5-300 K. The meta-material, realized from an array of tapers ≈100 μm in length, is largely insensitive to the detailed geometry of these elements and is cryogenically compatible with silicon-based micro-machined technologies. The electromagnetic response is in general agreement with a physically motivated transmission line model.

  10. Calibration of the AKARI Far-Infrared Imaging Fourier Transform Spectrometer

    CERN Document Server

    Murakami, Noriko; Takahashi, Hidenori; Okada, Yoko; Yasuda, Akiko; Ootsubo, Takafumi; Kaneda, Hidehiro; Matsuo, Hiroshi; Baluteau, Jean-Paul; Davis-Imhof, Peter; Gom, Brad G; Naylor, David A; Zavagno, Annie; Yamamura, Issei; Matsuura, Shuji; Shirahata, Mai; Doi, Yasuo; Nakagawa, Takao; Shibai, Hiroshi

    2010-01-01

    The Far-Infrared Surveyor (FIS) onboard the AKARI satellite has a spectroscopic capability provided by a Fourier transform spectrometer (FIS-FTS). FIS-FTS is the first space-borne imaging FTS dedicated to far-infrared astronomical observations. We describe the calibration process of the FIS-FTS and discuss its accuracy and reliability. The calibration is based on the observational data of bright astronomical sources as well as two instrumental sources. We have compared the FIS-FTS spectra with the spectra obtained from the Long Wavelength Spectrometer (LWS) of the Infrared Space Observatory (ISO) having a similar spectral coverage. The present calibration method accurately reproduces the spectra of several solar system objects having a reliable spectral model. Under this condition the relative uncertainty of the calibration of the continuum is estimated to be $\\pm$ 15% for SW, $\\pm$ 10% for 70-85 cm^(-1) of LW, and $\\pm$ 20% for 60-70 cm^(-1) of LW; and the absolute uncertainty is estimated to be +35/-55% for...

  11. The far-infrared - radio correlation in dwarf galaxies

    CERN Document Server

    Schleicher, Dominik R G

    2016-01-01

    The far-infrared - radio correlation connects star formation and magnetic fields in galaxies, and has been confirmed over a large range of far-infrared luminosities. Recent investigations indicate that it may even hold in the regime of local dwarf galaxies, and we explore here the expected behavior in the regime of star formation surface densities below 0.1 M_sun kpc^{-2} yr^{-1}. We derive two conditions that can be particularly relevant for inducing a change in the expected correlation: a critical star formation surface density to maintain the correlation between star formation rate and the magnetic field, and a critical star formation surface density below which cosmic ray diffusion losses dominate over their injection via supernova explosions. For rotation periods shorter than 1.5x10^7 (H/kpc)^2 yrs, with H the scale height of the disk, the first correlation will break down before diffusion losses are relevant, as higher star formation rates are required to maintain the correlation between star formation ...

  12. Far-infrared Spectroscopic Characterization of Anti-vinyl Alcohol

    Science.gov (United States)

    Bunn, Hayley; Soliday, Rebekah M.; Sumner, Isaiah; Raston, Paul L.

    2017-09-01

    We report a detailed analysis of the high-resolution far-infrared spectrum of anti-vinyl alcohol, which has been previously identified toward Sagittarius B2(N). The ν 15 OH torsional fundamental investigated here is more than 200 cm‑1 removed from the next nearest vibration, making it practically unperturbed and ideal to help refine the ground state rotational constants that were previously determined from 25 microwave lines. We assigned 1335 lines within the ν 15 fundamental centered at 261.5512 cm‑1, with J and K a ranges of 1–59 and 0–16, respectively. The microwave and far-infrared line positions were fit with Watson-type A- and S-reduced Hamiltonians, with the inclusion of quartic and select sextic distortion terms. This resulted in a significant refinement of the ground state constants, in addition to the determination of the {ν }15=1 state constants for the first time. The spectroscopic parameters are in good agreement with the results from anharmonic coupled-cluster calculations, and should be useful in searches for rotationally and/or vibrationally warm anti-vinyl alcohol in interstellar molecular clouds.

  13. Far-infrared spectra of the tryptamine A conformer by IR-UV ion gain spectroscopy

    NARCIS (Netherlands)

    Schmitt, M.; Spiering, F.; Zhaunerchyk, V.; Jongma, R.T.; Jaeqx, S.; Rijs, A.M.; van der Zande, W.J.

    2016-01-01

    We present far infrared spectra of the conformer A of tryptamine in the 200 to 500 cm-1 wavenumber range along with resonant photoionization spectra of the far-infrared excited conformer A of tryptamine. We show that single-far-infrared photon excited tryptamine has highly structured resonance enhan

  14. Bayesian method for the analysis of the dust emission in the Far-Infrared and Submillimeter

    CERN Document Server

    Veneziani, M; Noriega-Crespo, A; Carey, S; Paladini, R; Paradis, D

    2013-01-01

    We present a method, based on Bayesian statistics, to fit the dust emission parameters in the far-infrared and submillimeter wavelengths. The method estimates the dust temperature and spectral emissivity index, plus their relationship, taking into account properly the statistical and systematic uncertainties. We test it on three sets of simulated sources detectable by the Herschel Space Observatory in the PACS and SPIRE spectral bands (70-500 micron), spanning over a wide range of dust temperatures. The simulated observations are a one-component Interstellar Medium, and two two-component sources, both warm (HII regions) and cold (cold clumps). We first define a procedure to identify the better model, then we recover the parameters of the model and measure their physical correlations by means of a Monte Carlo Markov Chain algorithm adopting multi-variate Gaussian priors. In this process we assess the reliability of the model recovery, and of parameters estimation. We conclude that the model and parameters are ...

  15. Observing Star and Planet Formation in the Submillimeter and Far Infrared

    Science.gov (United States)

    Yorke, Harold W.

    2004-01-01

    Stars from in the densest parts of cold interstellar clouds which-due to presence of obscuring dust-cannot be observed with optical telescopes. Recent rapid progress in understanding how stars and planets are formed has gone hand in hand with our ability to observe extremely young systems in the infrared and (submillimeter) spectral regimes. The detections and silhouetted imaging of disks around young objects in the visible and NIR have demonstrated the common occurrence of circumstellar disks and their associated jets and outflows in star forming regions. However, in order to obtain quantitative information pertaining to even earlier evolutionary phases, studies at longer wavelengths are necessary. From spectro-photometric imaging at all wavelengths we learn about the temperature and density structure of the young stellar environment. From narrow band imaging in the far infrared and submillimeter spectral regimes we can learn much about the velocity structure and the chemical makeup (pre-biotic material) of the planet-forming regions.

  16. Serendipity observations of far infrared cirrus emission in the Spitzer Infrared Nearby Galaxies Survey: Analysis of far-infrared correlations

    CERN Document Server

    Bot, Caroline; Boulanger, Francois; Lagache, Guilaine; Miville-Deschenes, Marc-Antoine; Draine, Bruce; Martin, Peter

    2009-01-01

    We present an analysis of far-infrared dust emission from diffuse cirrus clouds. This study is based on serendipitous observations at 160 microns at high galactic latitude with the Multiband Imaging Photometer (MIPS) onboard the Spitzer Space Telescope by the Spitzer Infrared Nearby Galaxies Survey (SINGS). These observations are complemented with IRIS data at 100 and 60 microns and constitute one of the most sensitive and unbiased samples of far infrared observations at small scale of diffuse interstellar clouds. Outside regions dominated by the cosmic infrared background fluctuations, we observe a substantial scatter in the 160/100 colors from cirrus emission. We compared the 160/100 color variations to 60/100 colors in the same fields and find a trend of decreasing 60/100 with increasing 160/100. This trend can not be accounted for by current dust models by changing solely the interstellar radiation field. It requires a significant change of dust properties such as grain size distribution or emissivity or ...

  17. Topological structure effect on far-infrared spectra in a GaAs/InAs nanoring

    Institute of Scientific and Technical Information of China (English)

    Gu Li-Ying; Li Yan-Fang; Chu Wei-Dong; Wei Ying-Hui

    2012-01-01

    On the basis of the growth mechanism of a GaAs/InAe nanoring,we propose a fine model which reflects the confinement details of real nanoring.Through calculations of the two-electron energy and far-infrared (FIR) spectra,we find that the ring topological structure and electron-electron interaction have great influence on the FIR spectra.The two unknown transition peaks in the experiment are determined theoretically.The theoretical results are in good agreement with the experiments.

  18. A test setup for the characterization of far-infrared filters under cryogenic conditions

    Science.gov (United States)

    Birkmann, Stephan M.; Grözinger, Ulrich; Stegmaier, Jutta; Krause, Oliver; Pitz, Eckhard; Lemke, Dietrich

    2006-06-01

    The characterization and calibration of far-infrared (FIR) detectors is a delicate task that requires good knowledge of the incident flux and its spectral composition. In many test setups the FIR flux to the detectors is provided by means of an external or internal black body and a set of cold attenuation, band pass, and blocking filters. For scientific instruments (e.g. PACS aboard ESA's Herschel satellite) band pass and blocking filters are used to achieve the desired spectral throughput either as order sorting filters in spectrometers or for selecting a wavelength range in imaging cameras. In all cases a detailed knowledge of the spectral transmittance of the used filters is mandatory for an accurate calibration of the system. We have build a test platform that allows to measure the transmission of cold (T ~ 4K) filters in the far-infrared. The setup uses a dual grating monochromator with excellent spectral purity and a resolution up to 800, which is operated under a dry nitrogen atmosphere to eliminate water vapor absorption bands. An Si-bolometer is used as detector and is read out by a cryogenic low noise trans-impedance amplifier circuit with common mode rejection and a warm electronics using a lock-in amplifier and a 22 bit analog-to-digital converter. A cryogenic filter slider in the setup allows for differential measurements between filters and the use of cold order sorting filters. We present initial results for FIR cut-on and attenuation filters, demonstrating that our setup is suited to measure transmissions as low as 10 -4 over the covered wavelength range.

  19. Development of low-noise kinetic inductance detectors for far-infrared astrophysics

    Science.gov (United States)

    Barlis, Alyssa; Hailey-Dunsheath, Steven; Bradford, Charles M.; McKenney, Christopher; Le Duc, Henry G.; Aguirre, James

    2017-01-01

    The star formation mechanisms at work in the early universe remain one of the major unsolved problems of modern astrophysics. Many spectral lines at far-infrared wavelengths (10 μm working to develop a detector system for a far-infrared balloon-borne spectroscopic experiment using kinetic inductance detectors (KIDs), which have the potential to achieve high sensitivity, low noise levels, high multiplexing factor, and may enable future space missions. We describe the design, fabrication, and noise performance measurements of prototype detector devices targeting an optical noise equivalent power below 1 ×10-17 WHz - 1 / 2 with readout frequencies below 250 MHz. The devices consist of arrays of 45 lumped-element KID pixels patterned out of thin-film aluminum on silicon wafers. They are optically coupled to incident radiation with a set of feedhorns. We use an FPGA-based readout system to read out the response of all the pixels in the array simultaneously. This work was supported by a NASA Space Technology Research Fellowship.

  20. Radio Wavelength Constraints on the Sources of the Far Infrared Background

    CERN Document Server

    Haarsma, D B

    1998-01-01

    The cosmic far infrared background detected recently by the COBE-DIRBE team is presumably due, in large part, to the far infrared (FIR) emission from all galaxies. We take the well-established correlation between FIR and radio luminosity for individual galaxies and apply it to the FIR background. We find that these sources make up about half of the extragalactic radio background, the other half being due to AGN. This is in agreement with other radio observations, which leads us to conclude that the FIR-radio correlation holds well for the very faint sources making up the FIR background, and that the FIR background is indeed due to star-formation activity (not AGN or other possible sources). If these star-forming galaxies have a radio spectral index between 0.4 and 0.8, and make up 40 to 60% of the extragalactic radio background, we find that they have redshifts between roughly 1 and 2, in agreement with recent estimates by Madau et al. of the redshift of peak star-formation activity. We compare the observed e...

  1. The Far-Infrared Properties of the Most Isolated Galaxies

    Science.gov (United States)

    Lisenfeld, U.; Verdes-Montenegro, L.; Sulentic, J.; Leon, S.; Espada, D.; Bergond, G.; García, E.; Sabater, J.; Santander-Vela, J. D.; Verley, S.

    2007-05-01

    A long-standing question in galaxy evolution involves the role of nature (self-regulation) vs. nurture (environment) on the observed properties (and evolution) of galaxies. A collaboration centreed at the Instituto de Astrofisica de Andalucia (Granada, Spain) is trying to address this question by producing a observational database for a sample of 1050 isolated galaxies from the catalogue of Karachentseva (1973) with the overarching goal being the generation of a "zero-point" sample against which effects of environment on galaxies can be assessed. The AMIGA (Analysis of the Interstellar Medium of Isolated Galaxies) database (see www.iaa.es/AMIGA.html) will include optical, IR and radio line and continuum measures. The galaxies in the sample represent the most isolated galaxies in the local universe. In the present contribution, we will present the project, as well as the results of an analysis of the far-infrared (FIR) and molecular gas properties of this sample.

  2. Far-infrared emissivity measurements of reflective surfaces

    Science.gov (United States)

    Xu, J.; Lange, A. E.; Bock, J. J.

    1996-01-01

    An instrument developed to measure the emissivity of reflective surfaces by comparing the thermal emission of a test sample to that of a reference surface is reported. The instrument can accurately measure the emissivity of mirrors made from lightweight thermally insulating materials such as glass and metallized carbon fiber reinforced plastics. Far infrared measurements at a wavelength of 165 micrometers are reported. The instrument has an absolute accuracy of Delta epsilon = 9 x 10(exp -4) and can reproducibly measure an emissivity of as small as 2 x 10(exp -4) between flat reflective surfaces. The instrument was used to measure mirror samples for balloon-borne and spaceborne experiments. An emissivity of (6.05 +/- 1.24) x 10(exp -3) was measured for gold evaporated on glass, and (6.75 +/- 1.17) x 10(exp -3) for aluminum evaporated on glass.

  3. Far Infrared Optical Properties of Bulk Wurtzite Zinc Oxide Semiconductor

    Institute of Scientific and Technical Information of China (English)

    Pohkok Ooi; Saicheong Lee; Shashiong Ng; Zainuriah Hassan; Haslan Abu Hassan

    2011-01-01

    Polarized far infrared (FIR) reflectance technique was applied to study the optical properties of a bulk wurtzite zinc oxide (ZnO) single crystal. Room temperature polarized FIR reflectance spectra were taken at various angles of incidence, from 20° to 70°. The theoretical polarized FIR reflectance spectra were simulated based on the anisotropic dielectric function model. Good agreement was achieved between the experimental and the theoretical FIR reflectance spectra. Through this work, a complete set of reststrahlen parameters of a bulk wurtzite ZnO at the Brillouin zone centre was obtained. Additionally, other FIR optical properties such as the real and the imaginary parts of the complex dielectric function, real and imaginary parts of the refractive index, the absorption coefficient and the reciprocal of the absorption coefficient were also obtained by using numerical calculation.

  4. Active Control of Nitride Plasmonic Dispersion in the Far Infrared.

    Energy Technology Data Exchange (ETDEWEB)

    Shaner, Eric A.; Dyer, Gregory Conrad; Seng, William Francis; Bethke, Donald Thomas; Grine, Albert Dario,; Baca, Albert G.; Allerman, Andrew A.

    2014-11-01

    We investigate plasmonic structures in nitride-based materials for far-infrared (IR) applications. The two dimensional electron gas (2DEG) in the GaN/AlGaN material system, much like metal- dielectric structures, is a patternable plasmonic medium. However, it also permits for direct tunability via an applied voltage. While there have been proof-of-principle demonstrations of plasma excitations in nitride 2DEGs, exploration of the potential of this material system has thus far been limited. We recently demonstrated coherent phenomena such as the formation of plasmonic crystals, strong coupling of tunable crystal defects to a plasmonic crystal, and electromagnetically induced transparency in GaAs/AlGaAs 2DEGs at sub-THz frequencies. In this project, we explore whether these effects can be realized in nitride 2DEG materials above 1 THz and at temperatures exceeding 77 K.

  5. SEDeblend: A new method for deblending spectral energy distributions in confused imaging

    CERN Document Server

    MacKenzie, Todd; Swinbank, Mark

    2015-01-01

    For high-redshift submillimetre or millimetre sources detected with single dish telescopes, interferometric follow-up has shown that many are multiple submm galaxies blended together. Confusion-limited Herschel observations of such targets are also available, and these sample the peak of their spectral energy distribution in the far-infrared. Many methods for analysing these data have been adopted, but most follow the traditional approach of extracting fluxes before model spectral energy distributions are fit, which has the potential to erase important information on degeneracies among fitting parameters and glosses over the intricacies of confusion noise. Here, we adapt the forward-modelling method that we originally developed to disentangle a high-redshift strongly-lensed galaxy group, in order to tackle this problem in a more statistically rigorous way, by combining source deblending and SED fitting into the same procedure. We call this method "SEDeblend." As an application, we derive constraints on far-in...

  6. Cleanability evaluation of ceramic glazes with nanometer far-infrared materials using contact angle measurement.

    Science.gov (United States)

    Wang, Lijuan; Liang, Jinsheng; Di, Xingfu; Tang, Qingguo

    2014-05-01

    The cleanability of easy-to-clean ceramic glazes doped with nanometer far-infrared materials was compared with that of some high-quality household ceramic glazes from the market. The cleanability was evaluated by the contact angle measurement using a sessile drop method with a Dataphysics OCA-30 contact angle analyzer. The results showed that the difference of contact angles of water on the glazes before soiling and after cleaning could be used as a parameter for evaluating the cleanability of the glazes. The relationship between cleanability and surface properties, such as surface free energy and surface topography, was investigated. The surface free energy of the samples and their components were calculated using van Oss acid-base approach. By measuring advancing and receding contact angles, the contact angle hysteresis of the ceramic glazes due to the surface topography was investigated. It was shown that the cleanability of ceramic glazes containing nanometer far-infrared materials (NFIM) is better than that of household ceramic glazes from market, due to a higher ratio of electron-acceptor parameter to electron-donor parameter, which led to the effect of water hydration as well as better hydrophilic property and increased smoothness. The contact angle measurement not only accurately evaluates the cleanability of the ceramic glazes, but also has a contribution to the study of cleanability theory. Moreover, this method is simple, convenient and less sample-consumption.

  7. Heavy ozone distribution in the stratosphere from far-infrared observations

    Science.gov (United States)

    Abbas, M. M.; Guo, J.; Carli, B.; Mencaraglia, F.; Carlotti, M.; Nolt, I. G.

    1987-01-01

    The distribution of isotopically heavy ozone in the stratosphere has been obtained from analysis of balloon-based high-resolution thermal emission spectra in the far infrared. The mixing ratio profiles of (O-16)(O-16)(O-18) and (O-16)(O-18)(O-16), retrieved from inversion of several limb sequences of a number of spectral lines in the 39-76/cm region, indicate enhancements over the expected values in the 25- to 37-km altitude range. The ratio of total heavy isotopic ozone (10-50)3 to normal (O-48)3 shows enhancements of about 45 percent at 37 km, decreasing to a minimum of about 13 percent at 29 km, and increasing to about 18 percent at 25 km. The results from this work are compared with Mauersberger's (1987) in situ mass spectrometer measurements.

  8. Far-infrared polarimetry from the Stratospheric Observatory for Infrared Astronomy

    CERN Document Server

    Vaillancourt, J E; Crutcher, R M; Dotson, J L; Dowell, C D; Harper, D A; Hildebrand, R H; Jones, T J; Lazarian, A; Novak, G; Werner, M W

    2007-01-01

    Multi-wavelength imaging polarimetry at far-infrared wavelengths has proven to be an excellent tool for studying the physical properties of dust, molecular clouds, and magnetic fields in the interstellar medium. Although these wavelengths are only observable from airborne or space-based platforms, no first-generation instrument for the Stratospheric Observatory for Infrared Astronomy (SOFIA) is presently designed with polarimetric capabilities. We study several options for upgrading the High-resolution Airborne Wideband Camera (HAWC) to a sensitive FIR polarimeter. HAWC is a 12 x 32 pixel bolometer camera designed to cover the 53 - 215 micron spectral range in 4 colors, all at diffraction-limited resolution (5 - 21 arcsec). Upgrade options include: (1) an external set of optics which modulates the polarization state of the incoming radiation before entering the cryostat window; (2) internal polarizing optics; and (3) a replacement of the current detector array with two state-of-the-art superconducting bolomet...

  9. The Far-Infrared Spectrum of Arp 220

    Science.gov (United States)

    Gonzalez-Alfonso, Eduardo; Smith, Howard A.; Fischer, Jacqueline; Cernicharo, Jose

    2005-01-01

    ISO/LWS grating observations of the ultraluminous infrared galaxy Arp 220 shows absorption in molecular lines of OH, H(sub 2)O, CH, NH, and NH(sub 3), as well as in the [O I] 63 micron line and emission in the [C II] 158 micron line. We have modeled the continuum and the emission/absorption of all observed features by means of a non-local radiative transfer code. The continuum from 25 to 1300 microns is modeled as a warm (106 K) nuclear region that is optically thick in the far-infrared, attenuated by an extended region (size 2") that is heated mainly through absorption of nuclear infrared radiation. The molecular absorption in the nuclear region is characterized by high excitation due to the high infrared radiation density. The OH column densities are high toward the nucleus (2 - 6 x 10(exp 17) cm(exp -2)) and the extended region (approximately 2 x 10(exp 17) cm(exp -2)). The H(sub 2)O column density is also high toward the nucleus (2 - 10 x 10(exp 17) cm(exp -2)) and lower in the extended region. The column densities in a halo that accounts for the absorption by the lowest lying levels are similar to what are found in the diffuse clouds toward the star forming regions in the Sgr B2 molecular cloud complex near the Galactic Center. Most notable are the high column densities found for NH and NH(sub 3) toward the nucleus, with values of approximately 1.5 x 10(exp 16) cm(exp -2) and approximately 3 x 10(exp 16) cm(exp -2), respectively, whereas the NH(sub 2) column density is lower than approximately 2 x 10(exp 15) cm(exp -2). A combination of PDRs in the extended region and hot cores with enhanced H(sub 2)O photodissociation and a possible shock contribution in the nuclei may explain the relative column densities of OH and H(sub 2)O, whereas the nitrogen chemistry may be strongly affected by cosmic ray ionization. The [C II] 158 micron line is well reproduced by our models and its deficit relative to the CII/FIR ratio in normal and starburst galaxies is suggested to

  10. On the radiative and thermodynamic properties of the extragalactic far infrared background radiation using COBE FIRAS instrument data

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Using the explicit form of the function to describe the average spectrum of the extragalactic far infrared background (FIRB) radiation measured by the COBE FIRAS instrument in the 0.15 - 2.4 THz frequency interval, the radiative and thermodynamic properties, such as the total emissivity, total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, pressure, enthalpy density, and internal energy density are calculated. The calculated value of the total intensity received in the 0.15 - 2.4 THz frequency interval is 13.6 nW m^-2 sr^-1, and comprises about 19.4 % of the total intensity expected from the energy released by stellar nucleosynthesis over cosmic history. The radiative and thermodynamic functions of the extragalactic far infrared background (FIRB) radiation are calculated at redshift z = 1.5.

  11. HerMES: THE FAR-INFRARED EMISSION FROM DUST-OBSCURED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Calanog, J. A.; Wardlow, J.; Fu, Hai; Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Assef, R. J. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Bock, J.; Riechers, D.; Schulz, B. [California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Casey, C. M. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Farrah, D.; Oliver, S. J.; Roseboom, I. G. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Ibar, E. [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile); Kartaltepe, J. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Magdis, G.; Rigopoulou, D. [Department of Astrophysics, Denys Wilkinson Building, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Marchetti, L. [Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA (United Kingdom); Pérez-Fournon, I. [Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Scott, Douglas [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); and others

    2013-09-20

    Dust-obscured galaxies (DOGs) are an ultraviolet-faint, infrared-bright galaxy population that reside at z ∼ 2 and are believed to be in a phase of dusty star-forming and active galactic nucleus (AGN) activity. We present far-infrared (far-IR) observations of a complete sample of DOGs in the 2 deg{sup 2} of the Cosmic Evolution Survey. The 3077 DOGs have (z) = 1.9 ± 0.3 and are selected from 24 μm and r {sup +} observations using a color cut of r {sup +} – [24] ≥ 7.5 (AB mag) and S{sub 24} ≥ 100 μJy. Based on the near-IR spectral energy distributions, 47% are bump DOGs (star formation dominated) and 10% are power-law DOGs (AGN-dominated). We use SPIRE far-IR photometry from the Herschel Multi-tiered Extragalactic Survey to calculate the IR luminosity and characteristic dust temperature for the 1572 (51%) DOGs that are detected at 250 μm (≥3σ). For the remaining 1505 (49%) that are undetected, we perform a median stacking analysis to probe fainter luminosities. Herschel-detected and undetected DOGs have average luminosities of (2.8 ± 0.4) × 10{sup 12} L{sub ☉} and (0.77 ± 0.08) × 10{sup 12} L{sub ☉}, and dust temperatures of (33 ± 7) K and (37 ± 5) K, respectively. The IR luminosity function for DOGs with S{sub 24} ≥ 100 μJy is calculated, using far-IR observations and stacking. DOGs contribute 10%-30% to the total star formation rate (SFR) density of the universe at z = 1.5-2.5, dominated by 250 μm detected and bump DOGs. For comparison, DOGs contribute 30% to the SFR density for all z = 1.5-2.5 galaxies with S{sub 24} ≥ 100 μJy. DOGs have a large scatter about the star formation main sequence and their specific SFRs show that the observed phase of star formation could be responsible for their total observed stellar mass at z ∼ 2.

  12. Dust models post-Planck: constraining the far-infrared opacity of dust in the diffuse interstellar medium

    CERN Document Server

    Fanciullo, Lapo; Aniano, Gonzalo; Jones, Anthony P; Ysard, Nathalie; Miville-Deschênes, Marc-Antoine; Boulanger, François; Köhler, M

    2015-01-01

    We compare the performance of several dust models in reproducing the dust spectral energy distribution (SED) per unit extinction in the diffuse interstellar medium (ISM). We use our results to constrain the variability of the optical properties of big grains in the diffuse ISM, as published by the Planck collaboration. We use two different techniques to compare the predictions of dust models to data from the Planck HFI, IRAS and SDSS surveys. First, we fit the far-infrared emission spectrum to recover the dust extinction and the intensity of the interstellar radiation field (ISRF). Second, we infer the ISRF intensity from the total power emitted by dust per unit extinction, and then predict the emission spectrum. In both cases, we test the ability of the models to reproduce dust emission and extinction at the same time. We identify two issues. Not all models can reproduce the average dust emission per unit extinction: there are differences of up to a factor $\\sim2$ between models, and the best accord between ...

  13. Mid- and far-infrared properties of Spitzer Galactic bubbles revealed by the AKARI all-sky surveys

    CERN Document Server

    Hattori, Yasuki; Ishihara, Daisuke; Fukui, Yasuo; Torii, Kazufumi; Hanaoka, Misaki; Kokusho, Takuma; Kondo, Akino; Shichi, Kazuyuki; Ukai, Sota; Yamagishi, Mitsuyoshi; Yamaguchi, Yuta

    2016-01-01

    We have carried out a statistical study on the mid- and far-infrared (IR) properties of Galactic IR bubbles observed by Spitzer. Using the Spitzer 8 ${\\mu}{\\rm m}$ images, we estimated the radii and covering fractions of their shells, and categorized them into closed, broken and unclassified bubbles with our data analysis method. Then, using the AKARI all-sky images at wavelengths of 9, 18, 65, 90, 140 and 160 ${\\mu}{\\rm m}$, we obtained the spatial distributions and the luminosities of polycyclic aromatic hydrocarbon (PAH), warm and cold dust components by decomposing 6-band spectral energy distributions with model fitting. As a result, 180 sample bubbles show a wide range of the total IR luminosities corresponding to the bolometric luminosities of a single B-type star to many O-type stars. For all the bubbles, we investigated relationships between the radius, luminosities and luminosity ratios, and found that there are overall similarities in the IR properties among the bubbles regardless of their morpholog...

  14. Mapping metals at high redshift with far-infrared lines

    CERN Document Server

    Pallottini, A; Ferrara, A; Yue, B; Vallini, L; Maiolino, R; Feruglio, C

    2015-01-01

    Cosmic metal enrichment is one of the key physical processes regulating galaxy formation and the evolution of the intergalactic medium (IGM). However, determining the metal content of the most distant galaxies has proven so far almost impossible; also, absorption line experiments at $z\\sim6$ become increasingly difficult because of instrumental limitations and the paucity of background quasars. With the advent of ALMA, far-infrared emission lines provide a novel tool to study early metal enrichment. Among these, the [CII] line at 157.74 $\\mu$m is the most luminous line emitted by the interstellar medium of galaxies. It can also resonant scatter CMB photons inducing characteristic intensity fluctuations ($\\Delta I/I_{CMB}$) near the peak of the CMB spectrum, thus allowing to probe the low-density IGM. We compute both [CII] galaxy emission and metal-induced CMB fluctuations at $z\\sim 6$ by using Adaptive Mesh Refinement cosmological hydrodynamical simulations and produce mock observations to be directly compare...

  15. Operation results of the KSTAR far infrared interferometer

    Science.gov (United States)

    Juhn, June-Woo; Lee, K. C.; Wi, H. M.; Kim, Y. S.; Nam, Y. U.

    2016-11-01

    The 2015 KSTAR experimental campaign was the first year of routine measurement with a far infrared interferometer (FIRI) utilizing 118.87 μm CH3OH lasers at maximum 200 mW CW beam power. By using rtEFIT reconstruction, the path lengths of interferometers can be calculated and so the line-averaged electron densities n ¯ e from the FIRI and a millimeter-wave interferometer were in excellent agreement. In this way, the number of successfully diagnosed discharges is counted: 1003 shots or 83.7% of sustained discharges, defined as shots of plasma current IP ≥ 0.3 MA with pulse lengths tf ≥ 2.0 s, have good-quality FIRI data within a few fringe jump errors. In addition, real-time H-mode density feedback control based on the FIRI was also successfully achieved with supersonic molecular beam injection as an actuator. Both constant density and controlled linear increment with a ramp-up rate of 1.0 × 1019 m-3 s-1 were achieved.

  16. Upgrade of the electronics of the JET far infrared interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Gil, C., E-mail: christophe.gil@cea.fr [JET-EFDA Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Barbuti, A.; Pastor, P.; Spuig, P.; Vincent, B. [JET-EFDA Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Boboc, A.; Dorling, S.; Edlington, T.; Simpson, D. [JET-EFDA Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Euratom-CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2013-10-15

    Highlights: ► Analogue and digital boards have been realized to simultaneously measure the phase of the two wavelength sine signals of the vertical channels of the JET the interferometer. ► Real time fringe jump correction algorithms are embedded in the FPGA processor. ► The electronics has been tested during the 2012 JET plasma campaign comparatively to the existing JET electronics. ► The efficiency of the new electronics is better than the older existing one. -- Abstract: For the new bicolour vertical channels of the JET far infrared interferometer, CEA developed analogue and digital electronics to measure by time delay counting the variation of phase of the two wavelength beams that have crossed the plasma. Algorithms to simultaneously correct, at the time scale of the period of the sine signals, the possible fringe jumps of the two wavelength signals are embedded in a FPGA processor. Laboratory tests to validate the fringe jump corrections are reported and the first results of the phase measurements on plasmas are analyzed and compared with the data that are produced by the existing JET electronics.

  17. The Far-Infrared Surveyor (FIS) for AKARI

    CERN Document Server

    Kawada, Mitsunobu; Barthel, Peter D; Clements, David; Cohen, Martin; Doi, Yasuo; Figueredo, Elysandra; Fujiwara, Mikio; Goto, Tomotsugu; Hasegawa, Sunao; Hibi, Yasunori; Hirao, Takanori; Hiromoto, Norihisa; Jeong, Woong-Seob; Kaneda, Hidehiro; Kawai, Toshihide; Kawamura, Akiko; Kester, Do; Kii, Tsuneo; Kobayashi, Hisato; Kwon, Suk Minn; Lee, Hyung Mok; Makiuti, Sin'itirou; Matsuo, Hiroshi; Matsuura, Shuji; Müller, Thomas G; Murakami, Noriko; Nagata, Hirohisa; Nakagawa, Takao; Narita, Masanao; Noda, Manabu; Oh, Sang Hoon; Okada, Yoko; Okuda, Haruyuki; Oliver, Sebastian; Ootsubo, Takafumi; Pak, Soojong; Park, Yong-Sun; Pearson, Chris P; Rowan-Robinson, Michael; Saito, Toshinobu; Salama, Alberto; Sato, Shinji; Savage, Richard S; Serjeant, Stephen; Shibai, Hiroshi; Shirahata, Mai; Sohn, Jungjoo; Suzuki, Toyoaki; Takagi, Toshinobu; Takahashi, Hidenori; Thomson, Matthew; Usui, Fumihiko; Verdugo, Eva; Watabe, Toyoki; White, Glenn J; Wang, Lingyu; Yamamura, Issei; Yamamuchi, Chisato; Yasuda, Akiko

    2007-01-01

    The Far-Infrared Surveyor (FIS) is one of two focal plane instruments on the AKARI satellite. FIS has four photometric bands at 65, 90, 140, and 160 um, and uses two kinds of array detectors. The FIS arrays and optics are designed to sweep the sky with high spatial resolution and redundancy. The actual scan width is more than eight arcmin, and the pixel pitch is matches the diffraction limit of the telescope. Derived point spread functions (PSFs) from observations of asteroids are similar to the optical model. Significant excesses, however, are clearly seen around tails of the PSFs, whose contributions are about 30% of the total power. All FIS functions are operating well in orbit, and its performance meets the laboratory characterizations, except for the two longer wavelength bands, which are not performing as well as characterized. Furthermore, the FIS has a spectroscopic capability using a Fourier transform spectrometer (FTS). Because the FTS takes advantage of the optics and detectors of the photometer, i...

  18. The far-infrared spectrum of Arp 220

    CERN Document Server

    González-Alfonso, E; Fischer, J; Cernicharo, J

    2004-01-01

    ISO/LWS grating observations of the ultraluminous infrared galaxy Arp 220 shows absorption in molecular lines of OH, H$_2$O, CH, NH, and NH$_3$, as well as in the [O I] 63 $\\mu$m line and emission in the [C II] 158 $\\mu$m line. We have modeled the continuum and the emission/absorption of all observed features by means of a non-local radiative transfer code. The continuum from 25 to 1300 $\\mu$m is modeled as a warm (106 K) nuclear region that is optically thick in the far-infrared, attenuated by an extended region (size 2$''$) that is heated mainly through absorption of nuclear infrared radiation. The molecular absorption in the nuclear region is characterized by high excitation due to the high infrared radiation density. The OH column densities are high toward the nucleus and the extended region. The H$_2$O column density is also high toward the nucleus and lower in the extended region. The column densities in a halo are similar to what are found in the diffuse clouds toward Sgr B2 near the Galactic Center. M...

  19. Far-infrared extinction mapping of infrared dark clouds

    CERN Document Server

    Lim, Wanggi

    2013-01-01

    Progress in understanding star formation requires detailed observational constraints on the initial conditions, i.e. dense clumps and cores in giant molecular clouds that are on the verge of gravitational instability. Such structures have been studied by their extinction of Near-Infrared (NIR) and, more recently, Mid-Infrared (MIR) background light. It has been somewhat more of a surprise to find that there are regions that appear as dark shadows at Far-Infrared (FIR) wavelengths as long as $\\sim$100$\\mu m$. Here we develop analysis methods of FIR images from Spitzer-MIPS and Herschel-PACS that allow quantitative measurements of cloud mass surface density, $\\Sigma$. The method builds upon that developed for MIR extinction mapping (MIREX) (Butler and Tan 2012), in particular involving a search for independent saturated, i.e. very opaque, regions that allow measurement of the foreground intensity. We focus on three massive starless core/clumps in IRDC G028.37+00.07, deriving mass surface density maps from 3.5 t...

  20. FAR-INFRARED PROPERTIES OF TYPE 1 QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Hanish, D. J.; Teplitz, H. I.; Capak, P.; Desai, V.; Armus, L.; Brinkworth, C.; Brooke, T.; Colbert, J.; Fadda, D.; Noriega-Crespo, A.; Paladini, R. [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 E California Blvd., Pasadena, CA 91125 (United States); Frayer, D. [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States); Huynh, M. [International Centre for Radio Astronomy Research, M468, University of Western Australia, Crawley, WA 6009 (Australia); Lacy, M. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Murphy, E. [The Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Scarlata, C. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Shenoy, S., E-mail: hanish@ipac.caltech.edu [Space Science Division, NASA Ames Research Center, M/S 245-6, Moffett Field, CA 94035 (United States)

    2013-05-01

    We use the Spitzer Space Telescope Enhanced Imaging Products and the Spitzer Archival Far-InfraRed Extragalactic Survey to study the spectral energy distributions (SEDs) of spectroscopically confirmed type 1 quasars selected from the Sloan Digital Sky Survey (SDSS). By combining the Spitzer and SDSS data with the Two Micron All Sky Survey, we are able to construct a statistically robust rest-frame 0.1-100 {mu}m type 1 quasar template. We find that the quasar population is well-described by a single power-law SED at wavelengths less than 20 {mu}m, in good agreement with previous work. However, at longer wavelengths, we find a significant excess in infrared luminosity above an extrapolated power-law, along with significant object-to-object dispersion in the SED. The mean excess reaches a maximum of 0.8 dex at rest-frame wavelengths near 100 {mu}m.

  1. Far-Infrared Properties of Type 1 Quasars

    CERN Document Server

    Hanish, D J; Capak, P; Desai, V; Armus, L; Brinkworth, C; Brooke, T; Colbert, J; Fadda, D; Frayer, D; Huynh, M; Lacy, M; Murphy, E; Noriega-Crespo, A; Paladini, R; Scarlata, C; Shenoy, S

    2013-01-01

    We use the Spitzer Space Telescope Enhanced Imaging Products (SEIP) and the Spitzer Archival Far-InfraRed Extragalactic Survey (SAFIRES) to study the spectral energy distributions of spectroscopically confirmed type 1 quasars selected from the Sloan Digital Sky Survey (SDSS). By combining the Spitzer and SDSS data with the 2-Micron All Sky Survey (2MASS) we are able to construct a statistically robust rest-frame 0.1-100 micron type 1 quasar template. We find the quasar population is well-described by a single power-law SED at wavelengths less than 20 microns, in good agreement with previous work. However, at longer wavelengths we find a significant excess in infrared luminosity above an extrapolated power-law, along with signifiant object-to-object dispersion in the SED. The mean excess reaches a maximum of 0.8 dex at rest-frame wavelengths near 100 microns.

  2. Infrared-faint radio sources remain undetected at far-infrared wavelengths. Deep photometric observations using the Herschel Space Observatory

    Science.gov (United States)

    Herzog, A.; Norris, R. P.; Middelberg, E.; Spitler, L. R.; Leipski, C.; Parker, Q. A.

    2015-08-01

    Context. Showing 1.4 GHz flux densities in the range of a few to a few tens of mJy, infrared-faint radio sources (IFRS) are a type of galaxy characterised by faint or absent near-infrared counterparts and consequently extreme radio-to-infrared flux density ratios up to several thousand. Recent studies showed that IFRS are radio-loud active galactic nuclei (AGNs) at redshifts ≳2, potentially linked to high-redshift radio galaxies (HzRGs). Aims: This work explores the far-infrared emission of IFRS, providing crucial information on the star forming and AGN activity of IFRS. Furthermore, the data enable examining the putative relationship between IFRS and HzRGs and testing whether IFRS are more distant or fainter siblings of these massive galaxies. Methods: A sample of six IFRS was observed with the Herschel Space Observatory between 100 μm and 500 μm. Using these results, we constrained the nature of IFRS by modelling their broad-band spectral energy distribution (SED). Furthermore, we set an upper limit on their infrared SED and decomposed their emission into contributions from an AGN and from star forming activity. Results: All six observed IFRS were undetected in all five Herschel far-infrared channels (stacking limits: σ = 0.74 mJy at 100 μm, σ = 3.45 mJy at 500 μm). Based on our SED modelling, we ruled out the following objects to explain the photometric characteristics of IFRS: (a) known radio-loud quasars and compact steep-spectrum sources at any redshift; (b) starburst galaxies with and without an AGN and Seyfert galaxies at any redshift, even if the templates were modified; and (c) known HzRGs at z ≲ 10.5. We find that the IFRS analysed in this work can only be explained by objects that fulfil the selection criteria of HzRGs. More precisely, IFRS could be (a) known HzRGs at very high redshifts (z ≳ 10.5); (b) low-luminosity siblings of HzRGs with additional dust obscuration at lower redshifts; (c) scaled or unscaled versions of Cygnus A at any

  3. Far-infrared HD emission as a measure of protoplanetary disk mass

    Science.gov (United States)

    Trapman, L.; Miotello, A.; Kama, M.; van Dishoeck, E. F.; Bruderer, S.

    2017-09-01

    Context. Protoplanetary disks around young stars are the sites of planet formation. While the dust mass can be estimated using standard methods, determining the gas mass - and thus the amount of material available to form giant planets - has proven to be very difficult. Hydrogen deuteride (HD) is a promising alternative to the commonly used gas mass tracer, carbon monoxide. However, the potential of HD has not yet been investigated with models incorporating both HD and CO isotopologue-specific chemistry, and its sensitivity to uncertainties in disk parameters has not yet been quantified. Aims: We examine the robustness of HD as tracer of the disk gas mass, specifically the effect of gas mass on HD far-infrared emission and its sensitivity to the vertical structure. Also, we seek to provide requirements for future far-infrared missions such as SPICA. Methods: Deuterium chemistry reactions relevant for HD were implemented in the thermochemical code DALI and more than 160 disk models were run for a range of disk masses and vertical structures. Results: The HD J = 1-0 line intensity depends directly on the gas mass through a sublinear power law relation with a slope of 0.8. Assuming no prior knowledge about the vertical structure of a disk and using only the HD 1-0 flux, gas masses can be estimated to within a factor of two for low mass disks (Mdisk ≤ 10-3M⊙). For more massive disks, this uncertainty increases to more than an order of magnitude. Adding the HD 2-1 line or independent information about the vertical structure can reduce this uncertainty to a factor of 3 for all disk masses. For TW Hya, using the radial and vertical structure from the literature, the observations constrain the gas mass to 6 × 10-3M⊙ ≤ Mdisk ≤ 9 × 10-3M⊙. Future observations require a 5σ sensitivity of 1.8 × 10-20 W m-2 (2.5 × 10-20 W m-2) and a spectral resolving power R ≥ 300 (1000) to detect HD 1-0 (HD 2-1) for all disk masses above 10-5M⊙ with a line

  4. SEDEBLEND: a new method for deblending spectral energy distributions in confused imaging

    Science.gov (United States)

    MacKenzie, Todd P.; Scott, Douglas; Swinbank, Mark

    2016-11-01

    For high-redshift submillimetre or millimetre sources detected with single-dish telescopes, interferometric follow-up has shown that many are multiple submillimetre galaxies blended together. Confusion-limited Herschel observations of such targets are also available, and these sample the peak of their spectral energy distribution (SED) in the far-infrared. Many methods for analysing these data have been adopted, but most follow the traditional approach of extracting fluxes before model SEDs are fit, which has the potential to erase important information on degeneracies among fitting parameters and glosses over the intricacies of confusion noise. Here, we adapt the forward-modelling method that we originally developed to disentangle a high-redshift strongly lensed galaxy group, in order to tackle this general problem in a more statistically rigorous way, by combining source deblending and SED fitting into the same procedure. We call this method `SEDeblend'. As an application, we derive constraints on far-infrared luminosities and dust temperatures for sources within the ALMA follow-up of the LABOCA Extended Chandra Deep Field South Submillimetre Survey. We find an average dust temperature for an 870-μm-selected sample of (33.9 ± 2.4) K for the full survey. When selection effects of the sample are considered, we find no evidence that the average dust temperature evolves with redshift for sources with redshifts greater than about 1.5, when compared to those with redshifts between 0.1 and 1.5.

  5. The Infrared Spectral Energy Distribution of Normal Star-Forming Galaxies

    CERN Document Server

    Dale, D A; Contursi, A; Silbermann, N A; Kolhatkar, S; Dale, Daniel A.; Helou, George; Contursi, Alessandra; Silbermann, Nancy A.; Kolhatkar, Sonali

    2001-01-01

    We present a new phenomenological model for the spectral energy distribution of normal star-forming galaxies between 3 and 1100 microns. A sequence of realistic galaxy spectra are constructed from a family of dust emission curves assuming a power law distribution of dust mass over a wide range of interstellar radiation fields. For each interstellar radiation field heating intensity we combine emission curves for large and very small grains and aromatic feature carriers. The model is constrained by IRAS and ISOCAM broadband photometric and ISOPHOT spectrophotometric observations for our sample of 69 normal galaxies; the model reproduces well the empirical spectra and infrared color trends. These model spectra allow us to determine the infrared energy budget for normal galaxies, and in particular to translate far-infrared fluxes into total (bolometric) infrared fluxes. The 20 to 42 micron range appears to show the most significant growth in relative terms as the activity level increases, suggesting that the 20-...

  6. Testing models of low-excitation photodissociation regions with far-infrared observations of reflection nebulae

    NARCIS (Netherlands)

    Owl, RCY; Meixner, MM; Fong, D; Haas, MR; Rudolph, AL; Tielens, AGGM

    2002-01-01

    This paper presents Kuiper Airborne Observatory observations of the photodissociation regions ( PDRs) in nine reflection nebulae. These observations include the far-infrared atomic fine-structure lines of [O I] 63 and 145 mum, [C II] 158 mum, and [Si II] 35 mum and the adjacent far-infrared continuu

  7. Evaluation of electron-electron interactions in coupled quantum dots by using far-infrared spectra

    Institute of Scientific and Technical Information of China (English)

    Dong Qing-Rui

    2008-01-01

    We have studied the far-infrared spectra of two-electron vertically coupled quantum dots in an axial magnetic field by exact diagonalization. The calculated results show an obvious difference in role between the interactions for spin S = 1 and for spin S = 0. The results support the possibility to evaluate the interactions by far-infrared spectroscopy in vertically coupled quantum dots.

  8. The evolution of far-infrared CO emission from protostars

    CERN Document Server

    Manoj, P; Megeath, S T; Evans, N J; Stutz, A M; Tobin, J J; Watson, D M; Fischer, W J; Furlan, E; Henning, T

    2016-01-01

    We investigate the evolution of far-IR CO emission from protostars observed with Herschel/PACS for 50 sources from the combined sample of HOPS and DIGIT Herschel key programs. From the uniformly sampled spectral energy distributions, we computed $L_{\\rm{bol}}$, $T_{\\rm{bol}}$ and $L_{\\rm {bol}}/L_{\\rm {smm}}$ for these sources to search for correlations between far-IR CO emission and protostellar properties. We find a strong and tight correlation between far-IR CO luminosity ($L^{\\rm fir}_{\\rm CO}$) and the bolometric luminosity ($L_{\\rm{bol}}$) of the protostars with $L^{\\rm fir}_{\\rm CO}$ $\\propto$ $L_{\\rm{bol}}^{0.7}$. We, however, do not find a strong correlation between $L^{\\rm fir}_{\\rm CO}$ and protostellar evolutionary indicators, $T_{\\rm{bol}}$ and $L_{\\rm {bol}}/L_{\\rm {smm}}$. FIR CO emission from protostars traces the currently shocked gas by jets/outflows, and $L^{\\rm fir}_{\\rm CO}$ is proportional to the instantaneous mass loss rate, $\\dot{M}_{\\rm{out}}$. The correlation between $L^{\\rm fir}_{\\r...

  9. A new interpretation of the far-infrared - radio correlation and the expected breakdown at high redshift

    CERN Document Server

    Schleicher, Dominik R G

    2013-01-01

    (Abrigded) Observations of galaxies up to z 2 show a tight correlation between far-infrared and radio continuum emission. We explain the far-infrared - radio continuum correlation by relating star formation and magnetic field strength in terms of turbulent magnetic field amplification, where turbulence is injected by supernova explosions from massive stars. We calculate the expected amount of turbulence in galaxies based on their star formation rates, and infer the expected magnetic field strength due to turbulent dynamo amplification. We estimate the timescales for cosmic ray energy losses via synchrotron emission, inverse Compton scattering, ionization and bremsstrahlung emission, probing up to which redshift strong synchrotron emission can be maintained. We find that the correlation between star formation rate and magnetic field strength in the local Universe can be understood as a result of turbulent magnetic field amplification. If the typical gas density in the interstellar medium increases at high z, w...

  10. Mid/far-infrared photo-detectors based on graphene asymmetric quantum wells

    Science.gov (United States)

    Ben Salem, E.; Chaabani, R.; Jaziri, S.

    2016-09-01

    We conducted a theoretical study on the electronic properties of a single-layer graphene asymmetric quantum well. Quantification of energy levels is limited by electron-hole conversion at the barrier interfaces and free-electron continuum. Electron-hole conversion at the barrier interfaces can be controlled by introducing an asymmetry between barriers and taking into account the effect of the interactions of the graphene sheet with the substrate. The interaction with the substrate induces an effective mass to carriers, allowing observation of Fabry-Pérot resonances under normal incidence and extinction of Klein tunneling. The asymmetry, between barriers creates a transmission gap between confined states and free-electron continuum, allowing the large graphene asymmetric quantum well to be exploited as a photo-detector operating at mid- and far-infrared frequency regimes.

  11. A four-pole power-combiner design for far-infrared and submillimeter spectroscopy

    CERN Document Server

    Cataldo, Giuseppe; Wollack, Edward J

    2015-01-01

    The far-infrared and submillimeter portions of the electromagnetic spectrum provide a unique view of the astrophysical processes present in the early universe. Micro-Spec ($\\mu$-Spec), a high-efficiency direct-detection spectrometer concept working in the 450-1000-$\\mu$m wavelength range, will enable a wide range of spaceflight missions that would otherwise be challenging due to the large size of current instruments and the required spectral resolution and sensitivity. This paper focuses on the $\\mu$-Spec two-dimensional multimode region, where the light of different wavelengths diffracts and converges onto a set of detectors. A two-step optimization process is used to generate geometrical configurations given specific requirements on spectrometer size, operating spectral range, and performance. The canonically employed focal-plane constraints for the power combiner were removed to probe the design space in its entirety. A new four-stigmatic-point optical design solution is identified and explored for use in ...

  12. Far-infrared spectroscopy of salt penetration into a collagen fiber scaffold.

    Science.gov (United States)

    Mizuno, Maya; Yamada, Akira; Fukunaga, Kaori; Kojima, Hiroaki

    2015-06-01

    We employed far-infrared spectroscopy to observe the amount of salt that penetrates into collagen fiber masses. The absorption properties of collagen sheets prepared from tilapia skin, bovine skin, rat tail, and sea cucumber dermis were measured using a transmission Fourier transform spectrometer in a band from approximately 100 to 700 cm(-1). We confirmed that the absorbance spectra of the four types of dried collagen sheet show good agreement, even though the amino acid compositions differed. The absorbance peaks observed in the band corresponded to collective vibrations of plural functional groups such as methylene and imino groups in collagen. When salt solution was added to the collagen sheets and then dried, the spectral shapes of the sheets at approximately 166 cm(-1) were clearly different from those of the plain collagen sheets. The differential absorbance between wavenumbers 166 cm(-1) and 250 cm(-1) sensitively reflected the difference between higher-order structures, and the salt diffusion (crystallization) depended on the collagen fiber condition. From these results, we consider that spectral changes can be used for the numerical evaluation of salt penetration into a collagen fiber scaffold.

  13. Environmental temperature effect on the far-infrared absorption features of aromatic-based Titan's aerosol analogs

    Science.gov (United States)

    Gautier, Thomas; Trainer, Melissa G.; Loeffler, Mark J.; Sebree, Joshua A.; Anderson, Carrie M.

    2017-01-01

    Benzene detection has been reported in Titan's atmosphere both in the stratosphere at ppb levels by remote sensing (Coustenis et al., 2007; Vinatier et al., 2007) and in the thermosphere at ppm levels by the Cassini's Ion and Neutral Mass Spectrometer (Waite et al., 2007). This detection supports the idea that aromatic and heteroaromatic reaction pathways may play an important role in Titan's atmospheric chemistry, especially in the formation of aerosols. Indeed, aromatic molecules are easily dissociated by ultraviolet radiation and can therefore contribute significantly to aerosol formation. It has been shown recently that aerosol analogs produced from a gas mixture containing a low concentration of aromatic and/or heteroaromatic molecules (benzene, naphthalene, pyridine, quinoline and isoquinoline) have spectral signatures below 500 cm-1, a first step towards reproducing the aerosol spectral features observed by Cassini's Composite InfraRed Spectrometer (CIRS) in the far infrared (Anderson and Samuelson 2011, and references therein). In this work we investigate the influence of environmental temperature on the absorption spectra of such aerosol samples, simulating the temperature range to which aerosols, once formed, are exposed during their transport through Titan's stratosphere. Our results show that environmental temperature does not have any major effect on the spectral shape of these aerosol analogs in the far-infrared, which is consistent with the CIRS observations.

  14. Design and instrumentation of an airborne far infrared radiometer for in-situ measurements of ice clouds

    Science.gov (United States)

    Proulx, Christian; Ngo Phong, Linh; Lamontagne, Frédéric; Wang, Min; Fisette, Bruno; Martin, Louis; Châteauneuf, François

    2016-09-01

    We report on the design and instrumentation of an aircraft-certified far infrared radiometer (FIRR) and the resulting instrument characteristics. FIRR was designed to perform unattended airborne measurements of ice clouds in the arctic in support of a microsatellite payload study. It provides radiometrically calibrated data in nine spectral channels in the range of 8-50 μm with the use of a rotating wheel of bandpass filters and reference blackbodies. Measurements in this spectral range are enabled with the use of a far infrared detector based on microbolometers of 104-μm pitch. The microbolometers have a new design because of the large structure and are coated with gold black to maintain uniform responsivity over the working spectral range. The vacuum sealed detector package is placed at the focal plane of a reflective telescope based on a Schwarschild configuration with two on-axis spherical mirrors. The telescope field-of-view is of 6° and illuminates an area of 2.1-mm diameter at the focal plane. In operation, FIRR was used as a nonimaging radiometer and exhibited a noise equivalent radiance in the range of 10-20 mW/m2-sr. The dynamic range and the detector vacuum integrity of FIRR were found to be suited for the conditions of the airborne experiments.

  15. Far-infrared/sub-millimetre properties of pre-stellar cores L1521E, L1521F and L1689B as revealed by the Herschel SPIRE instrument -- I. Central positions

    CERN Document Server

    Makiwa, Gibion; van der Wiel, Matthijs; Ward-Thompson, Derek; Kirk, Jason; Eyres, Stewart; Abergel, Alain; Koehler, Melanie

    2016-01-01

    Dust grains play a key role in the physics of star-forming regions, even though they constitute only $\\sim$1 % of the mass of the interstellar medium. The derivation of accurate dust parameters such as temperature ($T_{dust}$), emissivity spectral index ($\\beta$) and column density requires broadband continuum observations at far-infrared wavelengths. We present Herschel-SPIRE Fourier Transform Spectrometer (FTS) measurements of three starless cores: L1521E, L1521F and L1689B, covering wavelengths between 194 and 671 $\\mu$m. This paper is the first to use our recently updated SPIRE-FTS intensity calibration, yielding a direct match with SPIRE photometer measurements of extended sources. In addition, we carefully assess the validity of calibration schemes depending on source extent and on the strength of background emission. The broadband far-infrared spectra for all three sources peak near 250 $\\mu$m. Our observations therefore provide much tighter constraints on the spectral energy distribution (SED) shape t...

  16. Research Advance on Tea Processing and Production Based on Far Infrared Heating Technology%远红外加热技术在茶叶加工及制品中的研究进展

    Institute of Scientific and Technical Information of China (English)

    吴全金; 孙威江; 吴占富

    2014-01-01

    As a high efficient energy saving technology , far infrared heating technology has been widely used for heating agricultural products .In this paper , the advance on the application of far infrared technology in tea processing and quali-ty control were summarized , including the research in deactivation of enzymes and saving energy of equipment , and the effect of the quality of green tea processing .And then the problems of the spectral technology were discussed ,and the au-thors put forward that: the research workers should strengthen the research on the optimization of tea manufacturing processes , the development of far infrared equipment and continuous process system in future .%远红外加热技术作为一种高效节能的环保技术在农产品加工中得到广泛应用。为此,综述了远红外加热技术在茶叶生产加工和品质调控中的重要研究进展,主要包括基于远红外技术进行灭酶干燥工艺和设备节能改造研究,以及加工过程中对绿茶品质成分的影响研究。同时,分析了该技术在茶叶加工应用过程中存在的问题,并提出该技术的发展趋势:加强茶叶加工工艺优化及其理论研究、红外辐射装置研发、连续化系统开发等。

  17. Herschel Far-Infrared Photometry of the Swift Burst Alert Telescope Active Galactic Nuclei Sample of the Local Universe. II. SPIRE Observations

    CERN Document Server

    Shimizu, T Taro; Mushotzky, Richard F; Koss, Michael J; Barger, Amy J; Cowie, Lennox L

    2015-01-01

    We present far-infrared (FIR) and submillimeter photometry from the Herschel Space Observatory's Spectral and Photometric Imaging Receiver (SPIRE) for 313 nearby z<0.05 active galactic nuclei (AGN). We selected AGN from the 58 month Swift Burst Alert Telescope (BAT) catalog, the result of an all-sky survey in the 14-195 keV energy band, allowing for a reduction in AGN selection effects due to obscuration and host galaxy contamination. We find 46% (143/313) of our sample is detected at all three wavebands and combined with our PACS observations represents the most complete FIR spectral energy distributions of local, moderate luminosity AGN. We find no correlation between the 250, 350, and 500 micron luminosities with 14-195 keV luminosity, indicating the bulk of the FIR emission is not related to the AGN. However, Seyfert 1s do show a very weak correlation with X-ray luminosity compared to Seyfert 2s and we discuss possible explanations. We compare the SPIRE colors (F250/F350 and F350/F500) to a sample of n...

  18. Micro-spec: an Integrated Direct-detection Spectrometer for Far-infrared Space Telescopes

    Science.gov (United States)

    Cataldo, Giuseppe; Hsieh, Wen-Ting; Huang, Wei-Chung; Moseley, S. Harvey; Stevenson, Thomas R.; Wollack, Edward J.

    2014-01-01

    The far-infrared and submillimeter portions of the electromagnetic spectrum provide a unique view of the astrophysical processes present in the early universe. Our ability to fully explore this rich spectral region has been limited, however, by the size and cost of the cryogenic spectrometers required to carry out such measurements.Micro-Spec (µ-Spec) is a high-sensitivity, direct-detection spectrometer concept working in the 450-1000 (micrometers) wavelength range which will enable a wide range of flight missions that would otherwise be challenging due tothe large size of current instruments with the required spectral resolution and sensitivity. The spectrometer design utilizes two internal antenna arrays, one for transmitting and one for receiving, superconducting microstrip transmission lines for power division and phase delay, and an array of microwave kinetic inductance detectors (MKIDs) to achieve these goals. The instrument will be integrated on a approximately 10 sq cm silicon chip and can therefore become an important capability under the low background conditions accessible via space and high-altitude borne platforms. In this paper, an optical design methodology for micro-Spec is presented, with particular attention given to its two-dimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the maximization of the instrument resolving power and minimization of the RMS phase error on the instrument focal plane. This two-step optimization can generate geometrical configurations given specific requirements on spectrometer size, operating spectral range and performance.Two point designs with resolving power of 260 and 520 and an RMS phase error less than approximately 0.004 radians were developed for initial demonstration and will be the basis of future instruments with resolving power up to about 1200.

  19. Micro-Spec: an Integrated, Direct-Detection Spectrometer for Far-Infrared and Submillimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe

    2014-01-01

    The far-infrared and submillimeter portions of the electromagnetic spectrum provide a unique view of the astrophysical processes present in the early universe. Our ability to fully explore this rich spectral region has been limited, however, by the size and cost of the cryogenic spectrometers required to carry out such measurements. Micro-Spec (u-Spec) is a high-sensitivity, direct-detection spectrometer concept working in the 450-1000 micromillimeter wavelength range which will enable a wide range of flight missions that would otherwise be challenging due to the large size of current instruments with the required spectral resolution and sensitivity. The spectrometer design utilizes two internal antenna arrays, one for transmitting and one for receiving, superconducting microstrip transmission lines for power division and phase delay, and an array of microwave kinetic inductance detectors (MKIDs) to achieve these goals. The instrument will be integrated on a approximately 10 square cm silicon chip and can therefore become an important capability under the low background conditions accessible via space and high-altitude borne platforms. In this paper, an optical design methodology for Micro-Spec is presented, with particular attention given to its twodimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the maximization of the instrument resolving power and minimization of the RMS phase error on the instrument focal plane. This two-step optimization can generate geometrical configurations given specific requirements on spectrometer size, operating spectral range and performance. A point design with resolving power of 257, an RMS phase error less than 0.1 radians and four stigmatic points was developed for initial demonstration and will be the basis of future instruments with resolving power up to about 1200.

  20. Test of far-infrared atmospheric spectroscopy using wide-band balloon-borne measurements of the upwelling radiance

    Energy Technology Data Exchange (ETDEWEB)

    Bianchini, G. [Istituto di Fisica Applicata Nello Carrara-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)], E-mail: G.Bianchini@ifac.cnr.it; Carli, B.; Cortesi, U.; Del Bianco, S.; Gai, M.; Palchetti, L. [Istituto di Fisica Applicata Nello Carrara-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)

    2008-04-15

    The spectroscopy of the constituents of the Earth's atmosphere that are active in the far infrared spectral region, among which the water vapour is the main one, has been validated through the analysis of wide-band nadir-looking spectra acquired with the Radiation Explorer in the Far Infrared-Prototype for Applications and Development (REFIR-PAD) Fourier transform spectroradiometer. The spectra, covering from 100 to 1400cm{sup -1} with a 0.475cm{sup -1} unapodized resolution, were acquired during a balloon flight performed in a tropical region in 2005. Atmospheric variables, namely water vapour and temperature vertical profiles, were retrieved from the REFIR-PAD data, and the residuals of the fitting are here critically analysed for the search of systematic effects that can be ascribed to spectroscopic errors. In the spectral interval between 150 and 600cm{sup -1} nosignificant inconsistency is detected between the residuals and the measurement uncertainty, proving the good quality of the radiative transfer model and of the HITRAN 2004 spectroscopic database. Significant difference are instead observed when the HITRAN 2000 database is used.

  1. Water Vapor in Titan's Stratosphere from Cassini CIRS Far-Infrared Spectra

    Science.gov (United States)

    Cottini, V.; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bezard, B.; deKok, R,; Lellouch, E.; Irwin, P. G. J.; Flasar, F. M.; Bampasidis, G.

    2012-01-01

    Here we report the measurement of water vapor in Titan's stratosphere using the Cassini Composite Infrared Spectrometer (CIRS). CIRS senses water emissions in the far infrared spectral region near 50 micron, which we have modeled using two independent radiative transfer codes. From the analysis of nadir spectra we have derived a mixing ratio of 0.14 +/- 0.05 ppb at an altitude of 97 km, which corresponds to an integrated (from 0 to 600 km) surface normalized column abundance of 3.7 +/- 1.3 1014 molecules/cm2. In the latitude range 80S to 30N we see no evidence for latitudinal variations in these abundances within the error bars. Using limb observations, we obtained mixing ratios of 0.13 +/- 0.04 ppb at an altitude of 115 km and 0.45 +/- 0.15 ppb at an altitude of 230 km, confirming that the water abundance has a positive vertical gradient as predicted by photochemical models. We have also fitted our data using scaling factors of 0.1-0.6 to these photochemical model profiles, indicating that the models over-predict the water abundance in Titan's lower stratosphere.

  2. Radio Identifications of Markarian Galaxies and the Correlation between Radio and Far-Infrared Properties

    Institute of Scientific and Technical Information of China (English)

    Shao-Guang Luo; Xue-Bing Wu

    2005-01-01

    By checking DSS optical images and NVSS radio images, 782 Markarian galaxies were identified to be NVSS radio sources. A comparison of the radio luminosity at 1.4 GHz and the far-infrared (FIR) luminosity for 468 "normal"galaxies shows a tight correlation. Most of the Seyfert galaxies and quasars follow the radio-FIR relation deduced from the "normal" galaxy sample, but with a somewhat larger scatter. A total 167 Markarian galaxies, comprising 100 "normal"galaxies, 66 Seyfert galaxies and one quasar, have either excess radio emission or much lower FIR spectral index α(25μm, 60μm). These galaxies may be classified as "AGN-powered". For "normal" galaxies, the average q value (defined as the log ratio between FIR and radio luminosities) is 2.3. There seems a trend for q to slightly decrease with increasing radio luminosity. This may imply that the ongoing active star formation in galaxies with higher radio luminosities is more efficient in heating the cosmic-ray electrons.

  3. The Far Infrared Spectroscopic Explorer (FIRSPEX): probing the lifecycle of the ISM in the universe

    Science.gov (United States)

    Rigopoulou, D.; Caldwell, M.; Ellison, B.; Pearson, C.; Caux, E.; Cooray, A.; Gallego, J. D.; Gerin, M.; Goicoechea, J. R.; Goldsmith, P.; Kramer, C.; Lis, D. C.; Molinari, S.; Ossenkopf-Okada, V.; Savini, G.; Tan, B. K.; Tielens, X.; Viti, S.; Wiedner, M.; Yassin, G.

    2016-07-01

    The Far Infrared Spectroscopic Explorer (FIRSPEX) is a novel European-led astronomy mission concept developed to enable large area ultra high spectroscopic resolution surveys in the THz regime. FIRSPEX opens up a relatively unexplored spectral and spatial parameter space that will produce an enormously significant scientific legacy by focusing on the properties of the multi-phase ISM, the assembly of molecular clouds in our Galaxy and the onset of star formation; topics which are fundamental to our understanding of galaxy evolution. The mission uses a heterodyne instrument and a ~1.2 m primary antenna to scan large areas of the sky in a number of discreet spectroscopic channels from L2. The FIRSPEX bands centered at [CI] 809 GHz, [NII]1460 GHz, [CII]1900 GHz and [OI]4700 GHz have been carefully selected to target key atomic and ionic fine structure transitions difficult or impossible to access from the ground but fundamental to the study of the multi-phase ISM in the Universe. The need for state-of-the-art sensitivity dictates the use of superconducting mixers configured either as tunnel junctions or hot electron bolometers. This technology requires cooling to low temperatures, approaching 4K, in order to operate. The receivers will operate in double sideband configuration providing a total of 7 pixels on the sky. FIRSPEX will operate from L2 in both survey and pointed mode enabling velocity resolved spectroscopy of large areas of sky as well as targeted observations.

  4. A far-infrared molecular and atomic line survey of the Orion KL region

    CERN Document Server

    Lerate, M R; Swinyard, B M; Goicoechea, J R; Cernicharo, J; Grundy, T W; Lim, T L; Polehampton, E T; Baluteau, J P; Viti, S; Yates, J

    2006-01-01

    We have carried out a high spectral resolution line survey towards the Orion Kleinmann-Low (KL) cluster from 44-188 um. The observations were taken with the Long Wavelength Spectrometer (LWS) in Fabry-Perot mode, on board the Infrared Space Observatory (ISO). A total of 152 lines are clearly detected and a further 34 features are present as possible detections. The spectrum is dominated by the molecular species H2O, OH and CO, along with [OI] and [CII] lines from PDR or shocked gas and [OIII], [NIII] lines from the foreground M42 HII region. Several isotopic species, as well as NH3, are also detected. HDO and H3O+ are tentatively detected for the first time in the far-infrared range towards Orion-KL. A basic analysis of the line observations is carried out, by comparing with previous measurements and published models and deriving rotational temperatures and column densities in the case of the molecular species. The complexity of the region requires more sophisticated models for the interpretation of all the l...

  5. A Herschel resolved far-infrared dust ring around HD 207129

    CERN Document Server

    Marshall, J P; Montesinos, B; Krivov, A V; Eiroa, C; Absil, O; Bryden, G; Maldonado, J; Mora, A; Sanz-Forcada, J; Ardila, D; Augereau, J -Ch; Bayo, A; Del Burgo, C; Danchi, W; Ertel, S; Fedele, D; Fridlund, M; Lebreton, J; González-García, B M; Liseau, R; Meeus, G; Müller, S; Pilbratt, G L; Roberge, A; Stapelfeldt, K; Thébault, P; White, G J; Wolf, S

    2011-01-01

    Dusty debris discs around main sequence stars are thought to be the result of continuous collisional grinding of planetesimals in the system. The majority of these systems are unresolved and analysis of the dust properties is limited by the lack of information regarding the dust location.vThe Herschel DUNES key program is observing 133 nearby, Sun-like stars (<20 pc, FGK spectral type) in a volume limited survey to constrain the absolute incidence of cold dust around these stars by detection of far infrared excess emission at flux levels comparable to the Edgeworth-Kuiper belt (EKB). We have observed the Sun-like star HD 207129 with Herschel PACS and SPIRE. In all three PACS bands we resolve a ring-like structure consistent with scattered light observations. Using {\\alpha} Bo\\"otis as a reference point spread function (PSF), we deconvolved the images, clearly resolving the inner gap in the disc at both 70 and 100 {\\mu}m. We have resolved the dust-producing planetesimal belt of a debris disc at 100 {\\mu}m f...

  6. A Herschel resolved far-infrared dust ring around HD 207129

    Science.gov (United States)

    Marshall, J. P.; Löhne, T.; Montesinos, B.; Krivov, A. V.; Eiroa, C.; Absil, O.; Bryden, G.; Maldonado, J.; Mora, A.; Sanz-Forcada, J.; Ardila, D.; Augereau, J.-Ch.; Bayo, A.; Del Burgo, C.; Danchi, W.; Ertel, S.; Fedele, D.; Fridlund, M.; Lebreton, J.; González-García, B. M.; Liseau, R.; Meeus, G.; Müller, S.; Pilbratt, G. L.; Roberge, A.; Stapelfeldt, K.; Thébault, P.; White, G. J.; Wolf, S.

    2011-05-01

    Context. Dusty debris discs around main sequence stars are thought to be the result of continuous collisional grinding of planetesimals in the system. The majority of these systems are unresolved and analysis of the dust properties is limited by the lack of information regarding the dust location. Aims: The Herschel DUNES key program is observing 133 nearby, Sun-like stars (stars by detection of far infrared excess emission at flux levels comparable to the Edgeworth-Kuiper belt (EKB). Methods: We have observed the Sun-like star HD 207129 with Herschel PACS and SPIRE. In all three PACS bands we resolve a ring-like structure consistent with scattered light observations. Using α Boötis as a reference point spread function (PSF), we deconvolved the images, clearly resolving the inner gap in the disc at both 70 and 100 μm. Results: We have resolved the dust-producing planetesimal belt of a debris disc at 100 μm for the first time. We measure the radial profile and fractional luminosity of the disc, and compare the values to those of discs around stars of similar age and/or spectral type, placing this disc in context of other resolved discs observed by Herschel/DUNES. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  7. Terahertz and Far-Infrared Windows Opened at Dome A, Antarctica

    CERN Document Server

    Shi, Sheng-Cai; Yao, Qi-Jun; Lin, Zhen-Hui; Li, Xin-Xing; Duan, Wen-Ying; Matsuo, Hiroshi; Zhang, Qizhou; Yang, Ji; Ashley, M C B; Shang, Zhaohui; Hu, Zhong-Wen

    2016-01-01

    The terahertz and far-infrared (FIR) band, from approximately 0.3 THz to 15 THz (1 mm to 20 micron), is important for astrophysics as the thermal radiation of much of the universe peaks at these wavelengths and many spectral lines that trace the cycle of interstellar matter also lie within this band. However, water vapor renders the terrestrial atmosphere opaque to this frequency band over nearly all of the Earth's surface. Early radiometric measurements below 1 THz at Dome A, the highest point of the cold and dry Antarctic ice sheet, suggest that it may offer the best possible access for ground-based astronomical observations in the terahertz and FIR band. To address uncertainty in radiative transfer modelling, we carried out measurements of atmospheric radiation from Dome A spanning the entire water vapor pure rotation band from 20 micron to 350 micron wavelength by a Fourier transform spectrometer. Our measurements expose atmospheric windows having significant transmission throughout this band. Furthermore...

  8. CCSD(T) study of the far-infrared spectrum of ethyl methyl ether.

    Science.gov (United States)

    Senent, M L; Ruiz, R; Villa, M; Domínguez-Gómez, R

    2009-02-14

    Band positions and intensities for the far-infrared bands of ethyl methyl ether are variationally determined from a three-dimensional (3D) potential energy surface calculated with CCSD(T)/cc-pVTZ theory. For this purpose, the energies of 181 selected geometries computed optimizing 3n-9 parameters are fitted to a 3D Fourier series depending on three torsional coordinates. The zero point vibrational energy correction and the search of a correct definition of the methyl torsional coordinate are taken into consideration for obtaining very accurate frequencies. In addition, second order perturbation theory is applied on the two molecular conformers, trans and cis-gauche, in order to test the validity of the 3D model. Consequently, a new assignment of previous experimental bands, congruent with the new ab initio results, is proposed. For the most stable trans-conformer, the nu(30), nu(29), and nu(28) fundamental transitions, computed at 115.3, 206.5, and 255.2 cm(-1), are correlated with the observed bands at 115.4, 202, and 248 cm(-1). For the cis-gauche the three band positions are computed at 91.0, 192.5, and 243.8 cm(-1). Calculations on the -d(3) isotopomer confirm our assignment. Intensities are determined at room temperature and at 10 K. Structural parameters, potential energy barriers, anharmonic frequencies for the 3n-9 neglected modes, and rotational parameters (rotational and centrifugal distortion constants), are also provided.

  9. Deriving star formation histories from photometry using energy balance spectral energy distribution modelling

    CERN Document Server

    Smith, Daniel J B

    2015-01-01

    Panchromatic spectral energy distribution (SED) fitting is a critical tool for determining the physical properties of distant galaxies, such as their stellar mass and star formation rate. One widely used method is the publicly available MAGPHYS code. We build on our previous analysis (Hayward & Smith 2015) by presenting some modifications which enable MAGPHYS to automatically estimate galaxy star formation histories (SFHs), including uncertainties, based on ultra-violet to far-infrared photometry. We use state-of-the art synthetic photometry derived by performing three-dimensional dust radiative transfer on hydrodynamic simulations of isolated disc and merging galaxies to test how well the modified MAGPHYS is able to recover SFHs under idealised conditions, where the true SFH is known. We find that while the SFH of the model with the best fit to the synthetic photometry is a poor representation of the true SFH (showing large variations with the line-of-sight to the galaxy and spurious bursts of star forma...

  10. The Far-Infrared Surveyor Mission Study: Paper I, the Genesis

    Science.gov (United States)

    Meixner, M.; Cooray, A.; Carter, R.; DiPirro, M.; Flores, A.; Leisawitz, D.; Armus, L.; Battersby, C.; Bergin, E.; Bradford, C. M.; hide

    2017-01-01

    This paper describes the beginning of the Far-Infrared Surveyor mission study for NASA's Astrophysics Decadal 2020. We describe the scope of the study, and the open process approach of the Science and Technology Definition Team. We are currently developing the science cases and provide some preliminary highlights here. We note key areas for technological innovation and improvements necessary to make a Far-Infrared Surveyor mission a reality.

  11. The Far-Infrared Surveyor Mission study: paper I, the genesis

    Science.gov (United States)

    Meixner, M.; Cooray, A.; Carter, R.; DiPirro, M.; Flores, A.; Leisawitz, D.; Armus, L.; Battersby, C.; Bergin, E.; Bradford, C. M.; Ennico, K.; Melnick, G. J.; Milam, S.; Narayanan, D.; Pontoppidan, K.; Pope, A.; Roellig, T.; Sandstrom, K.; Su, K. Y. L.; Vieira, J.; Wright, E.; Zmuidzinas, J.; Alato, S.; Carey, S.; Gerin, M.; Helmich, F.; Menten, K.; Scott, D.; Sakon, I.; Vavrek, R.

    2016-07-01

    This paper describes the beginning of the Far-Infrared Surveyor mission study for NASA's Astrophysics Decadal 2020. We describe the scope of the study, and the open process approach of the Science and Technology Definition Team. We are currently developing the science cases and provide some preliminary highlights here. We note key areas for technological innovation and improvements necessary to make a Far-Infrared Surveyor mission a reality.

  12. The Far-Infrared Surveyor Mission Study: Paper I, the Genesis

    CERN Document Server

    Meixner, M; Carter, R; DiPirro, M; Flores, A; Leisawitz, D; Armus, L; Battersby, C; Bergin, E; Bradford, C M; Ennico, K; Melnick, G J; Milam, S; Narayanan, D; Pontoppidan, K; Pope, A; Roellig, T; Sandstrom, K; Su, K Y L; Vieira, J; Wright, E; Zmuidzinas, J; Alato, S; Carey, S; Gerin, M; Helmich, F; Menten, K; Scott, D; Sakon, I; Vavrek, R

    2016-01-01

    This paper describes the beginning of the Far-Infrared Surveyor mission study for NASA's Astrophysics Decadal 2020. We describe the scope of the study, and the open process approach of the Science and Technology Definition Team. We are currently developing the science cases and provide some preliminary highlights here. We note key areas for technological innovation and improvements necessary to make a Far-Infrared Surveyor mission a reality.

  13. The Influence of Chain Dynamics on theFar-Infrared Spectrum of Liquid Methanol

    Energy Technology Data Exchange (ETDEWEB)

    Woods, K.N.; /Stanford U., Phys. Dept.; Wiedemann, H.; /SLAC, SSRL

    2005-07-11

    Far-infrared absorption spectroscopy is used to investigate the low frequency ({center_dot} 100 cm{sup -1}) intermolecular interactions in liquid methanol. Using an intense source of far-infrared radiation, modes are elucidated at approximately 30 cm{sup -1} and 70 cm{sup -1} in the absorption spectrum. These modes are believed to arise from intermolecular bending and librational motions respectively and are successfully reproduced in an ab initio molecular dynamics simulation of methanol.

  14. Glass formation and properties of Ge-Te-BiI3 far infrared transmitting chalcohalide glasses.

    Science.gov (United States)

    Sun, Jie; Nie, Qiuhua; Wang, Xunsi; Dai, Shixun; Xu, Tiefeng; Wang, Guoxiang

    2011-09-01

    A novel series of Ge-Te-BiI(3) chalcogenide glasses were prepared by traditional melt-quenching method and the glass-forming region was determined. Properties measurements including density, Vis-NIR and infrared (IR) transmission spectra with FTIR, XRD, DSC were adopted to analyze the composition, structure and performance of the Ge-Te-BiI3 glass system. Based on the metallization criterion and band gap energy theory, the relationships between energy gap, metallization criterion and glass composition was investigated. The results show that with the addition of BiI3, the glasses-forming ability and thermal stability are improved. The values of energy band gap and metallization criterion are within the range of 0.627-0.343 eV and 0.177-0.131, respectively. These series of glasses have wide optical transmission window from 2.2 to 25 μm and can offer an alternative solution for far infrared transmitting applications.

  15. Far-Infrared Beam-splitter For CLARREO

    Science.gov (United States)

    Jordan, D. C.; Milanovic, Z.

    2008-12-01

    Hyper-spectral missions in the 5-50 um wavelength range over a long lifetime with a small calibration error requirement such as CLARREO have beam-splitter needs dictated by the specific details of the mission. Good performance over the long wavelength range (10 x in length) is technically challenging for a coating design. The long wavelength range and the long end of the wavelength band eliminate from consideration (due to bulk material absorption) many of the common beam-splitter substrate and beam-splitter coating materials typically used for LWIR space borne instruments. For a Fourier Transform Spectrometer (FTS) mission like CLARREO, the beam-splitter requirements are derived from the NEdN requirement (radiometric noise) and the radiometric uncertainty requirement (radiometric bias). The goal is for the beam-splitter to provide a high modulation of the signal resulting from the two beam interference. A material survey was done to determine the applicable beam-splitter substrate and coating candidate materials. Based on the survey, several preliminary designs were created and evaluated. A cesium iodine approach appears to work well and will be the subject of future activity. The plan is to design and manufacture a beam-splitter in Phase 1. In Phase 2 and Phase 3 a test set to characterize beam-splitter performance over the spectral range will be designed and constructed and the beam-splitter will be characterized using the test set.

  16. Far Infrared Spectrometry of the Cosmic Background Radiation

    Science.gov (United States)

    Mather, J. C.

    1974-01-01

    I describe two experiments to measure the cosmic background radiation near 1 mm wavelength. The first was a ground-based search for spectral lines, made with a Fabry-Perot interferometer and an InSb detector. The second is a measurement of the spectrum from 3 to 18 cm{sup -1}, made with a balloon-borne Fourier transform spectrometer. It is a polarizing Michelson interferometer, cooled in liquid helium, and operated with a germanium bolometer. I give the theory of operation, construction details, and experimental results. The first experiment was successfully completed but the second suffered equipment malfunction on its first flight. I describe the theory of Fourier transformations and give a new understanding of convolutional phase correction computations. I discuss for infrared bolometer calibration procedures, and tabulate test results on nine detectors. I describe methods of improving bolometer sensitivity with immersion optics and with conductive film blackening.

  17. Far-infrared optical constants of a selection of zincblende structure crystals at 300 K

    Science.gov (United States)

    Maslin, K. A.; Parker, T. J.; Patel, C.

    The far-infrared amplitude and phase reflection spectra of six group III-V single crystal compounds (GaP, GaAs, GaSb, InP, InAs, and InSb) and two group II-VI single crystal compounds (CdTe and ZnSe) with the zincblende structure have been determined at room temperature in the region of their reststrahlen bands by reflection dispersive Fourier transform spectroscopy. The measured amplitude and phase reflection spectra and values of the optical constants calculated from them are presented. As an illustration of weak mode anharmonicity in these crystals, the imaginary part of the anharmonic self-energy of the infrared-active transverse optic mode of ZnSe at the center of the Brillouin zone is calculated from its measured dielectric functions. Prominent features in the self-energy function in the region of the reststrahlen band are assigned as phonon combination bands with the aid of critical point phonon frequencies derived from an 11-parameter rigid-ion model.

  18. The effects of the CO wagging coordinate relaxation on the far-infrared torsional spectrum of acetone

    Science.gov (United States)

    Meléndez, F. J.; Luisa Senent, M.; Smeyers, Yves G.

    1997-02-01

    The effect of the full relaxation of the molecular geometry during the double internal methyl rotation in acetone is analyzed. For this purpose, the potential energy function for the double rotation in acetone is recalculated and the spectrum simulated. It is seen that the relaxation of the out-of-plane wagging coordinate shifts the far-infrared frequency of the antisymmetric fundamental vibration, ν17, by 1.8 cm -1, but leaves invariant the Raman symmetric ν12. Furthermore, the infrared intensities are somewhat reduced especially in the vibrationally excited states.

  19. The New Generation Atlas of Quasar Spectral Energy Distributions from Radio to X-rays

    CERN Document Server

    Shang, Zhaohui; Wills, Beverley J; Wills, Derek; Cales, Sabrina; Dale, Daniel A; Green, Richard F; Runnoe, Jessie; Nemmen, Rodrigo S; Gallagher, Sarah; Ganguly, Rajib; Hines, Dean C; Kelly, Benjamin; Kriss, Gerard A; Li, Jun; Tang, Baitian; Xie, Yanxia

    2011-01-01

    We have produced the next generation of quasar spectral energy distributions (SEDs), essentially updating the work of Elvis et al. (1994) by using high-quality data obtained with several space and ground-based telescopes, including NASA's Great Observatories. We present an atlas of SEDs of 85 optically bright, non-blazar quasars over the electromagnetic spectrum from radio to X-rays. The heterogeneous sample includes 27 radio-quiet and 58 radio-loud quasars. Most objects have quasi-simultaneous ultraviolet-optical spectroscopic data, supplemented with some far-ultraviolet spectra, and more than half also have Spitzer mid-infrared IRS spectra. The X-ray spectral parameters are collected from the literature where available. The radio, far-infrared, and near-infrared photometric data are also obtained from either the literature or new observations. We construct composite spectral energy distributions for radio-loud and radio-quiet objects and compare these to those of Elvis et al., finding that ours have similar...

  20. Far-Infrared Spectroscopy of Syn-Vinyl Alcohol

    Science.gov (United States)

    Raston, Paul; Bunn, Hayley

    2016-06-01

    Vinyl alcohol has been extensively studied in both the microwave and mid-IR spectral regions, where 9 out of 15 vibrational modes have been identified. Here we present the first far-IR spectrum of vinyl alcohol, collected below 700 wn at the Australian Synchrotron. The high resolution (0.001 wn) spectrum reveals the νb{11} and νb{15} fundamentals of syn-vinyl alcohol at 489 wn and 407 wn, in addition to two hot bands of the νb{15} mode at 369 wn and 323 wn. High J transitions in the R-branch of the νb{15} band were found to be perturbed by an a-axis Coriolis interaction with the nearby νb{11} state. The νb{15} torsional mode of syn-vinyl alcohol was fit using a Watson's A-reduced Hamiltonian to yield rotational, centrifugal distortion, and Coriolis coupling parameters. S. Saito, Chem. Phys. Lett. 42, 3 (1976) M. Rodler et al., J. Am. Chem. Soc. 106, 4029 (1948) Y. Koga et al., J. Mol. Spec. 145, 315 (1991) D-L. Joo et al., J. Mol. Spec. 197, 68 (1999)

  1. BLAST: the far-infrared/radio correlation in distant galaxies

    CERN Document Server

    Ivison, R J; Biggs, Andy D; Brandt, W N; Chapin, Edward L; Coppin, Kristen E K; Devlin, Mark J; Dickinson, Mark; Dunlop, James; Dye, Simon; Eales, Stephen A; Frayer, David T; Halpern, Mark; Hughes, David H; Ibar, Edo; Kovács, A; Marsden, Gaelen; Moncelsi, L; Netterfield, Calvin B; Pascale, Enzo; Patanchon, Guillaume; Rafferty, D A; Rex, Marie; Schinnerer, Eva; Scott, Douglas; Semisch, C; Smail, Ian; Swinbank, A M; Truch, Matthew D P; Tucker, Gregory S; Viero, Marco P; Walter, Fabian; Weiss, Axel; Wiebe, Donald V; Xue, Y Q

    2009-01-01

    We investigate the correlation between FIR and radio luminosities in distant galaxies, a lynchpin of modern astronomy. We use data from BLAST, Spitzer, LABOCA, the VLA and the GMRT in the ECDFS. For a catalogue of BLAST 250um-selected galaxies, we re-measure the 70-870um flux densities at the positions of their most likely 24um counterparts, which have a median [interquartile] redshift of 0.74 [0.25, 1.57]. From these, we determine the monochromatic flux density ratio, q_250 (= log_10 [S_250um/S_1,400MHz]), and the bolometric equivalent, q_IR. At z~0.6, where our 250um filter probes rest-frame 160um emission, we find no evolution relative to q_160 for local galaxies. We also stack the FIR and submm images at the positions of 24um- and radio-selected galaxies. The difference between q_IR seen for 250um- and radio-selected galaxies suggests star formation provides most of the IR luminosity in <~100uJy radio galaxies, but rather less for those in the mJy regime. For the 24um sample, the radio spectral index i...

  2. Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies.

    Science.gov (United States)

    Jackson, Michael; Zink, Lyndon R

    2015-12-18

    The generation and subsequent measurement of far-infrared radiation has found numerous applications in high-resolution spectroscopy, radio astronomy, and Terahertz imaging. For about 45 years, the generation of coherent, far-infrared radiation has been accomplished using the optically pumped molecular laser. Once far-infrared laser radiation is detected, the frequencies of these laser emissions are measured using a three-laser heterodyne technique. With this technique, the unknown frequency from the optically pumped molecular laser is mixed with the difference frequency between two stabilized, infrared reference frequencies. These reference frequencies are generated by independent carbon dioxide lasers, each stabilized using the fluorescence signal from an external, low pressure reference cell. The resulting beat between the known and unknown laser frequencies is monitored by a metal-insulator-metal point contact diode detector whose output is observed on a spectrum analyzer. The beat frequency between these laser emissions is subsequently measured and combined with the known reference frequencies to extrapolate the unknown far-infrared laser frequency. The resulting one-sigma fractional uncertainty for laser frequencies measured with this technique is ± 5 parts in 10(7). Accurately determining the frequency of far-infrared laser emissions is critical as they are often used as a reference for other measurements, as in the high-resolution spectroscopic investigations of free radicals using laser magnetic resonance. As part of this investigation, difluoromethane, CH2F2, was used as the far-infrared laser medium. In all, eight far-infrared laser frequencies were measured for the first time with frequencies ranging from 0.359 to 1.273 THz. Three of these laser emissions were discovered during this investigation and are reported with their optimal operating pressure, polarization with respect to the CO2 pump laser, and strength.

  3. Far-infrared signatures and inner hole sizes of protoplanetary discs undergoing inside-out dust dispersal

    CERN Document Server

    Ercolano, Barbara; Owen, James; Robitaille, Thomas

    2015-01-01

    By means of radiative transfer simulation we study the evolution of the far-infrared colours of protoplanetary discs undergoing inside-out dispersal, often referred to as transition discs. We show that a brightening of the mid and far-infrared emission from these objects is a natural consequence of the removal of the inner disc. Our results can fully explain recent observations of transition discs in the Chamaleon and Lupus star forming regions from the Herschel Gould Belt Survey, which show a higher median for the 70?um (Herschel PACS 1) band of known transition objects compared with primordial discs. Our theoretical results hence support the suggestion that the 70?um band may be a powerful diagnostic for the identi?cation of transition discs from photometry data, provided that the inner hole is larger than tens of AU, depending on spectral type. Furthermore we show that a comparison of photometry in the K , 12?um and 7u0?m bands to model tracks can provide a rough, but quick estimate of the inner hole size ...

  4. Far-Infrared and submillimeter properties of SDSS galaxies in the Herschel ATLAS science demonstration phase field

    Institute of Scientific and Technical Information of China (English)

    Man I Lam; Hong Wu; Yi-Nan Zhu; Zhi-Min Zhou

    2013-01-01

    Using the Herschel ATLAS science demonstration phase data crossidentified with SDSS DR7 spectra,we select 297 galaxies with F250μm > 5σ.The sample galaxies are classified into five morphological types,and more than 40% of the galaxies are peculiar/compact galaxies.The peculiar galaxies show higher farinfrared/submillimeter luminosity-to-mass ratios than the other types.We perform and analyze the correlations of far-infrared/submillimeter and Hα luminosities for different morphological types and different spectral types.The Spearman rank coefficient decreases and the scatter increases with the wavelength increasing from 100 μm to 500 μm.We conclude that a single Herschel SPIRE band is not good for tracing star formation activities in galaxies.AGNs contribute less to the far-infrared/submillimeter luminosities and do not show a difference from star-forming galaxies.However,the earlier type galaxies present significant deviations from the best fit of star-forming galaxies.

  5. Far infrared spectroscopy of star formation regions in M82

    Science.gov (United States)

    Duffy, P. B.; Erickson, E. F.; Haas, M. R.; Houck, J. R.

    1986-01-01

    Emission lines of (O III) at 52 microns and 88 microns and of (N III) at 57 microns in the nucleus of the galaxy M82 have been observed from the Kuiper Airborne Observatory with the facility's cooled grating spectrometer. The (N III) line has not been previously detected in any extragalactic source. The fluxes in the lines indicate approx 4 x 10 to the 7th power M of ionized gas and a large population of massive stars (equivalent to 5 x 10 to the 5th power 08.5 stars), sufficient to power the infrared luminosity of the nucleus. We use the 52 to 88 micron line intensity ratio to find an average electron density of 210 + or 75 in the nucleus; this is 10 to 100 times lower than values typically observed in individual compact HII regions in our Galaxy. The relative line strengths of the (O III) and (N III) lines imply an N(++)/O(++) ratio of 0.45 + or - 0.1, significantly lower than is measured by the same method in individual HII regions at similar galactocentric distances (equal to or less than 400 pc) in our Galaxy. This lower N(++)/O(++) ratio may be due to a lower N/O ratio, higher stellar temperatures, or both, in M82. At spectral resolutions of approx. 90 km/s, all three line profiles are similarly asymmetric. They can be well fitted by two Gaussian distributions with widths of approx. 150 km/s and central velocities of approx. 110 and approx. 295 km/s, bracketing the systemic velocity of the nucleus of approx. 210 km/s. Within uncertainties, both the N(++)/O(++) ratio and the electron density are the same for both Gaussian components; this indicates no major large-scale gradient in either quantity within the nucleus.

  6. Spectral Energy Distributions of SDSS Blazars

    Indian Academy of Sciences (India)

    H. Z. Li; L. E. Chen

    2014-09-01

    We compiled the radio, optical and X-ray data for SDSS sample, and presented broad band spectral index. The broad band energy distribution reveals that FSRQs and LBLs objects have similar spectral properties. However, HBLs have a separate distinct property. Even so, a unified scheme was also revealed from colour–colour diagram.

  7. Generation of tunable coherent far-infrared radiation using atomic Rydberg states

    Energy Technology Data Exchange (ETDEWEB)

    Bookless, W.

    1980-12-01

    A source of tunable far-infrared radiation has been constructed. The system has been operated at 91.6 cm/sup -1/ with a demonstrated tunability of .63 cm/sup -1/. The system is based on a Rydberg state transition in optically pumped potassium vapor. The transition energy is tuned by the application of an electric field to the excited vapor. The transition wavelength and the shifted wavelength were detected and measured by the use of a Michelson interferometer and a liquid helium cooled Ga:Ge bolometer and the data was reduced using Fast Fourier transform techniques. Extensive spectroscopy was done on the potassium vapor to elucidate the depopulation paths and rates of the excited levels. Both theoretical and experimental results are presented to support the conclusions of the research effort. Additionally, possible alternative approaches to the population of the excited state are explored and recommendations are made for the future development of this source as well as the potential uses of it in molecular spectroscopy.

  8. Thin-layer catalytic far-infrared radiation drying and flavour of tomato slices

    Directory of Open Access Journals (Sweden)

    Ernest Ekow Abano

    2014-06-01

    Full Text Available A far-infrared radiation (FIR catalytic laboratory dryer was designed by us and used to dry tomato. The kinetics of drying of tomato slices with FIR energy was dependent on both the distance from the heat source and the sample thickness. Numerical evaluation of the simplified Fick’s law for Fourier number showed that the effective moisture diffusivity increased from 0.193×10–9 to 1.893×10–9 m2/s, from 0.059×10–9 to 2.885×10–9 m2/s, and, from 0.170×10–9 to 4.531×10–9 m2/s for the 7, 9, and 11 mm thick slices as moisture content decreased. Application of FIR enhanced the flavour of the dried tomatoes by 36.6% when compared with the raw ones. The results demonstrate that in addition to shorter drying times, the flavour of the products can be enhanced with FIR. Therefore, FIR drying should be considered as an efficient drying method for tomato with respect to minimization of processing time, enhancement in flavour, and improvements in the quality and functional property of dried tomatoes.

  9. ISO far infrared observations of the high latitude cloud L1642. II. Correlated variations of far-infrared emissivity and temperature of "classical large" dust particles

    CERN Document Server

    Lehtinen, K; Mattila, K; Lemke, D; Russeil, D

    2007-01-01

    Our aim is to compare the infrared properties of big, ``classical'' dust grains with visual extinction in the cloud L1642. In particular, we study the differences of grain emissivity between diffuse and dense regions in the cloud. The far-infrared properties of dust are based on large-scale 100um and 200um maps. Extinction through the cloud has been derived by using the star count method at B- and I-bands, and color excess method at J, H and Ks bands. Radiative transfer calculations have been used to study the effects of increasing absorption cross-section on the far-infrared emission and dust temperature. Dust emissivity, measured by the ratio of far-infrared optical depth to visual extinction, tau(far-IR)/A(V), increases with decreasing dust temperature in L1642. There is about two-fold increase of emissivity over the dust temperature range of 19K-14K. Radiative transfer calculations show that in order to explain the observed decrease of dust temperature towards the centre of L1642 an increase of absorption...

  10. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: III. Galactic far-infrared radiation

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Using the three-component spectral model describing the FIRAS average continuum spectra, the analytical expressions for the temperature dependence of the thermodynamic and radiative functions of the galactic far-infrared radiation are obtained. The COBE FIRAS instrument data in the 0.15 - 2.88 THz frequency interval at the mean temperatures T = 17.72 K, T = 14 K, and T =6.73 K are used for calculating the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, total emissivity, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume and pressure for the warm, intermediate-temperature and very cold components of the Galactic continuum spectra. The generalized Stefan-Boltzmann laws for the warm, intermediate-temperature and very cold components are constructed. This result is important when we construct the cosmological models of radiative transfer in the inner Galaxy. Within the framework of the three- com...

  11. Latitudinal variation of upper tropospheric NH3 on Saturn derived from Cassini/CIRS far-infrared measurements

    Science.gov (United States)

    Hurley, J.; Fletcher, L. N.; Irwin, P. G. J.; Calcutt, S. B.; Sinclair, J. A.; Merlet, C.

    2012-12-01

    Ammonia (NH3) has been detected both on Saturn and Jupiter, and although its concentration and distribution has been well-studied on Jupiter, it has proven more difficult to do so on Saturn due to higher sensitivity requirements resulting from Saturn's lower atmospheric temperatures and the dominance of Saturn's phosphine which masks the ammonia signal. Using far-infrared measurements of Saturn taken by Cassini/CIRS between February 2005 and December 2010, the latitudinal variations of upper tropospheric ammonia on Saturn are studied. Sensitivity to NH3 in the far-infrared is explored to provide estimates of temperature, para-H2 and PH3, from 2.5 cm-1 spectral resolution measurements alone, 0.5 cm-1 spectral-resolution measurements alone, and 0.5 cm-1 measurements degraded to 2.5 cm-1 spectral resolution. The estimates of NH3 from these three different datasets largely agree, although there are notable differences using the high emission angle 0.5 cm-1 data, which are asserted to result from a reduction in sensitivity at higher emission angles. For low emission angles, the 0.5 cm-1-retrieved values of NH3 can be used to reproduce the 2.5 cm-1 spectra with similar efficacy as those derived directly from the 2.5 cm-1 resolution data itself, and vice versa. Using low emission angle data, NH3 is observed to have broad peak abundances at ±25° latitude, attributed to result from condensation and/or photolytic processes. Lack of data coverage at equatorial latitudes precludes analysis of NH3 abundance at less than about 10° latitude. Noise levels are not sufficient to distinguish fine zonal features, although it seems that NH3 cannot trace the zonal belt/zone structure in the upper troposphere of Saturn.

  12. Far-infrared metallicity diagnostics: application to local ultraluminous infrared galaxies

    Science.gov (United States)

    Pereira-Santaella, M.; Rigopoulou, D.; Farrah, D.; Lebouteiller, V.; Li, J.

    2017-09-01

    The abundance of metals in galaxies is a key parameter that permits to distinguish between different galaxy formation and evolution models. Most of the metallicity determinations are based on optical line ratios. However, the optical spectral range is subject to dust extinction and, for high-z objects (z > 3), some of the lines used in optical metallicity diagnostics are shifted to wavelengths not accessible to ground-based observatories. For this reason, we explore metallicity diagnostics using far-infrared (far-IR) line ratios which can provide a suitable alternative in such situations. To investigate these far-IR line ratios, we modelled the emission of a starburst with the photoionization code cloudy. The most sensitive far-IR ratios to measure metallicities are the [O iii]52 μm and 88 μm to [N iii]57 μm ratios. We show that this ratio produces robust metallicities in the presence of an active galactic nucleus and is insensitive to changes in the age of the ionizing stellar. Another metallicity-sensitive ratio is the [O iii]88 μm/[N ii]122 μm ratio, although it depends on the ionization parameter. We propose various mid- and far-IR line ratios to break this dependence. Finally, we apply these far-IR diagnostics to a sample of 19 local ultraluminous IR galaxies (ULIRGs) observed with Herschel and Spitzer. We find that the gas-phase metallicity in these local ULIRGs is in the range 0.7

  13. Electrochemically induced far-infrared difference spectroscopy on metalloproteins using advanced synchrotron technology.

    Science.gov (United States)

    Vita, Nicolas; Brubach, Jean-Blaise; Hienerwadel, Rainer; Bremond, Nicolas; Berthomieu, Dorothée; Roy, Pascale; Berthomieu, Catherine

    2013-03-05

    New information on a protein's structure, intra- and intermolecular hydrogen bonds, or metal-ligand bond properties can be unraveled in the far-infrared (far-IR)-terahertz-domain (600-3 cm(-1) or 18-0.1 THz). In this study, we compare the performances of thermal sources with synchrotron far-IR to record reaction-induced Fourier transform infrared (FT-IR) difference signals with proteins in solution. Using the model protein Cu-azurin placed in a short path length electrochemical cell adapted for transmission spectroscopy in vacuum-purged optics, we show that minute spectral shifts induced by metal isotope labeling or temperature changes are detected using the far-IR beamline AILES of the synchrotron SOLEIL. On one hand, these data allow us to identify modes involving Cu-ligand vibrations and pave the way for the analysis of metal sites or metal redox states of proteins not amenable to resonance Raman spectroscopy. On another hand, small band shifts or changes in band intensity upon temperature modifications show that far-IR difference spectroscopy allows one to extract from a complex background hydrogen-bonding signatures directly relevant to the protein function. For Cu-azurin, a temperature-sensitive IR mode involving Cu(II)-His vibrations points to the role of a hydrogen bond between a Cu histidine ligand and the water solvent in tuning the Cu(II)-histidine bond properties. Furthermore, these experimental data support the possible role of a His117-water interaction in electron-transfer activity of Cu-azurin proposed by theoretical studies.

  14. Water Vapor in Titan’s Stratosphere from Cassini CIRS Far-infrared Spectra

    Science.gov (United States)

    Cottini, Valeria; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bézard, B.; de Kok, R.; Lellouch, E.; Irwin, P. G. J.; Flasar, F. M.; Bampasidis, G.

    2012-10-01

    We will report the measurement of water vapor in Titan’s stratosphere (Cottini et al. 2012), using the Cassini Composite Infrared Spectrometer (CIRS, Flasar et al. 2004). CIRS senses water emissions in the far infrared spectral region near 50 microns, which we have modeled using a radiative transfer code (NEMESIS, Irwin et al. 2008). From the analysis of nadir spectra we have derived a mixing ratio of 0.14 ± 0.05 ppb at an altitude of 97 km, which corresponds to an integrated (from 0 to 600 km) surface normalized column abundance of 3.7±1.3 × 1014 molecules/cm2. In the latitude range 80°S to 30°N we see no evidence for latitudinal variations in these abundances within the error bars. Using limb observations, we obtained mixing ratios of 0.13 ± 0.04 ppb at an altitude of 115 km and 0.45 ± 0.15 ppb at an altitude of 230 km, confirming that the water abundance has a positive vertical gradient as predicted by previous photochemical models. We have also fitted our data using scaling factors of 0.1-0.6 to these photochemical model profiles, indicating that the models over-predict the water abundance in Titan’s lower stratosphere. Valeria Cottini is supported by the NASA Postdoctoral Program. References Cottini V. et al., 2012. Detection of water vapor in Titan’s atmosphere from Cassini/CIRS infrared spectra. Icarus, 220, 2, 855-862 Flasar, F.M., and 44 colleagues, 2004. Exploring the Saturn system in the thermal infrared: The Composite Infrared Spectrometer. Space Sci. Rev., 115, 169-297 Irwin, P.G.J., et al., 2008. The NEMESIS planetary atmosphere radiative transfer and retrieval tool. J. Quant. Spectrosc. Radiat. Trans., 109, 1136-1150.

  15. Far Infrared Spectroscopy of the Nearby Analogues of High-Redshift Galaxies

    Science.gov (United States)

    Hayes, Matthew

    2014-10-01

    We propose far infrared emission line spectroscopy of a sample of 23 local star-forming galaxies, drawn from the Lyman alpha Reference Sample (LARS), for which we have unrivalled high-resolution imaging and spectroscopy from HST, and 21cm HI observations from VLA+GMRT. Moreover the galaxies are selected as the close analogues of the high-redshift Lyman-break galaxies and Spitzer+Herschel selected galaxies found in extragalactic deep fields. The science goal of LARS is to determine what governs the escape of Lyman alpha (Lya) photons from galaxies, and thereby aid interpretation of high-z observations where Lya is the most used spectral probe. However given its clean selection and multiwavelength nature, LARS can equally well improve our understanding of FIR line observations of high-z galaxies. The target emission lines in this proposal are [CII], [OI], and [OIII] at 158, 63, and 88 micron, respectively. The motivations are that these lines: 1. are of increasing interest at high-z as new sensitive submm/radio interferometers come online 2. are proposed quantitative tracers of star formation rates, but their utility must be proven in appropriately analogous well-studied galaxies 3. when combined with models of photodissociation regions, enable estimates of the density and mass of PDR gas and provide vital constraints on our Lya radiative transfer models of galaxies. 4. provide uniquely robust estimates of nebular extinction and metallicity when combined with our optical IFU data. Astrophysical applications are many, especially when combined with the array of existing data. Specifically they will provide vital constraints on ISM structure, that are required for understanding the emission of the cosmologically vital Lya emission line. Moreover, SFR calibrations will be tested in star forming environments that resemble those of early galaxies and the legacy value of the sample is hard to overstate.

  16. An Electromagnetic Undulator for the Far Infrared at ELBE

    CERN Document Server

    Dekorsy, Thomas; Grosse, Eckart; Michel, Peter; Seidel, Wolfgang; Wolf, Andreas; Wuensch, Rudi

    2004-01-01

    The first lasing in the mid IR at the ELBE FEL allows us to specify the parameters of a new undulator for longer wavelengths to complement the U27 undulator which is useful up to about 25 microns. In the longer wavelength region FELs constitute a unique radiation source with appealing properties. Radiation quanta in this range (2 - 10 THz) are appropriate for the low-energy spectroscopy of various interesting modes in solid state quantum structures as well as in complex biological systems. Their study establishes the basis for understanding phenomena in semiconductors and elucidating biological processes of interest for medical innovations. We envisage an electromagnetic undulator with a period of 90 - 100 mm. Using the ELBE beam IR light from 20 to 150 microns and beyond can be produced. To keep the transverse beam extension small the IR beam is to be guided by a partial waveguide inside the undulator. Appropriate bifocal resonator mirrors minimize the mode coupling losses at the exits of the waveguide. Deta...

  17. Far-infrared polarisation of the quasar 3C 279

    CERN Document Server

    Klaas, U; Clavel, J; Klaas, Ulrich; Laureijs, Rene J.; Clavel, Jean

    1999-01-01

    We present the first FIR polarisation results of the OVV quasar 3C 279 obtained with ISOPHOT for two epochs in 1996 and 1997. We describe its integral polarisation properties at a wavelength of 170 micron where the source shows a maximum in its energy distribution. After a gamma-ray flare in January 1996, a polarisation of 23 % closely aligned with the radio jet axis was measured in July 1996. In June 1997, the polarisation degree had decreased to 6.5 % with a less good alignment. On the other hand, the total 170 micron flux is the same for both epochs. Our measurements provide additional constraints for the multi-wavelength properties of synchrotron emission in radio jets and the temporal evolution of these properties: they show that the FIR radiation of 3C 279 is optically thin and that its origin is very close to the core. The variability of the FIR polarisation without any change of the total FIR flux can be explained by a disordering of the magnetic field in between the core and the first stationary VLBI...

  18. Far-infrared-radio relation in cluster galaxies at intermediate redshift

    CERN Document Server

    Randriamampandry, Solohery M

    2016-01-01

    The radio luminosities at 1.4 GHz is tightly correlated with the far-infrared luminosities for various galaxy types (e.g. [16, 6, 2]) over a wide range of redshift (see e.g. [5, 1, 15, 8, 7]). The relationship is widely believed to be driven by the internal star formation activity. Radio emission from these galaxies are predominantly produced from the synchrotron emission of cosmic-ray electrons accelerated in supernova shocks. The infrared emission is due to ultraviolet light from young massive stars that is absorbed and re-radiated by dust [3]. A correlation is found also in local clusters but cluster galaxies appears to have excess radio emission relative to the amount of far-infrared emission [9, 13, 11]. In this work, we measure the far-infrared-radio relationship in a massive cluster to test how this relationship changes at intermediate z between the field and a high-density cluster environment.

  19. Far-infrared observations of Sagittarius B2: reconsideration of source structure

    Energy Technology Data Exchange (ETDEWEB)

    Thronson, H.A.,JR.; Harper, D.A.

    1985-10-01

    New moderate-angular-resolution far-infrared observations of the Sagittarius B2 star-forming region are presented, discussed, and compared with recent radio molecular and continuum observations of this source. In contrast to previous analyses, its far-infrared spectrum is interpreted as the result of a massive frigid cloud overlying a more-or-less normal infrared source, a natural explanation for the object's previously-noted pecularities. The characteristics derived for the obscuring cloud are similar to those found for the W51 MAIN object. Both sources have high sub-millimeter surface brightness, a high ratio of sub-millimeter to far-infrared flux, and numerous regions of molecular maser emission.

  20. Far-infrared observations of Sagittarius B2: Reconsideration of source structure

    Science.gov (United States)

    Thronson, H. A., Jr.; Harper, D. A.

    1985-01-01

    New moderate-angular-resolution far-infrared observations of the Sagittarius B2 star-forming region are presented, discussed, and compared with recent radio molecular and continuum observations of this source. In contrast to previous analyses, its far-infrared spectrum is interpreted as the result of a massive frigid cloud overlying a more-or-less normal infrared source, a natural explanation for the object's previously-noted pecularities. The characteristics derived for the obscuring cloud are similar to those found for the W51 MAIN object. Both sources have high sub-millimeter surface brightness, a high ratio of sub-millimeter to far-infrared flux, and numerous regions of molecular maser emission.

  1. Far-infrared observations of Sagittarius B2 - Reconsideration of source structure

    Science.gov (United States)

    Thronson, H. A., Jr.; Harper, D. A.

    1986-01-01

    New moderate-angular-resolution far-infrared observations of the Sagittarius B2 star-forming region are presented, discussed, and compared with recent radio molecular and continuum observations of this source. In contrast to previous analyses, its far-infrared spectrum is interpreted as the result of a massive frigid cloud overlying a more-or-less normal infrared source, a natural explanation for the object's previously-noted peculiarities. The characteristics derived for the obscuring cloud are similar to those found for the W51 MAIN object. Both sources have high sub-millimeter surface brightness, a high ratio of sub-millimeter to far-infrared flux, and numerous regions of molecular maser emission.

  2. Far-infrared observations of Sagittarius B2 - reconsideration of source structure

    Energy Technology Data Exchange (ETDEWEB)

    Thronson, H.A.,JR.; Harper, D.A.

    1986-01-01

    New moderate-angular-resolution far-infrared observations of the Sagittarius B2 star-forming region are presented, discussed, and compared with recent radio molecular and continuum observations of this source. In contrast to previous analyses, its far-infrared spectrum is interpreted as the result of a massive frigid cloud overlying a more-or-less normal infrared source, a natural explanation for the object's previously-noted peculiarities. The characteristics derived for the obscuring cloud are similar to those found for the W51 MAIN object. Both sources have high sub-millimeter surface brightness, a high ratio of sub-millimeter to far-infrared flux, and numerous regions of molecular maser emission. 28 references.

  3. Theoretic model of myocardial revascularization by far Infrared laser and experimental validation

    Institute of Scientific and Technical Information of China (English)

    LUO Le; CHEN Xing; ZHANG Ting; ZONG Ren-he; DENG Shan-xi

    2009-01-01

    A theoretic model of myocardial revascularization by a far infrared laser has been established and a quantificational rela-tionship between the aperture of laser channel and parameters of laser has been concluded according to thermodynamics and the law of mteraction of far infrared laser and myocardium. The experiment of a carbon dioxide laser revascularization in porcine myocardinm has been done for different laser powers and irradiation time. The relative errors between experi-mental result and theoretic computation are from 13% to 22%. The reasons that cause the errors have been studied in detail.

  4. Preparation and Characterization of Rare Earth Composite Materials Radiating Far Infrared for Activating Liquefied Petroleum Gas

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Rare earth composite materials radiating far-infrared rays were prepared according to far infrared absorption spectrum of main component in liquefied petroleum gas (LPG). The composite materials were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transformed infrared spectra(FTIR). The results show that after the composite materials were calcined at 873 K for 4 h, FTIR spectra of rare earth composite materials display two new peaks at 1336 and 2926 cm-1 available for activating LPG.

  5. Far-infrared colours of nearby late-type galaxies in the Herschel Reference Survey

    OpenAIRE

    Boselli, A.; Ciesla, L.; Cortese, L.; Buat, V.; Boquien, M.; Bendo, GJ; Boissier, S.; Eales, S; Gavazzi, G.; Hughes, TM; Pohlen, M.; Smith, MWL; Baes, Maarten; S. Bianchi; Clements, DL

    2012-01-01

    We study the far infrared (60-500 mu m) colours of late-type galaxies in the Herschel Reference Survey, a K-band selected, volume limited sample of nearby galaxies. The far infrared colours are correlated with each other, with tighter correlations for the indices that are closer in wavelength. We also compare the different colour indices to various tracers of the physical properties of the target galaxies, such as the surface brightness of the ionising and non-ionising stellar radiation, the ...

  6. Far-infrared spectroscopy of lanthanide-based molecular magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Sabrina

    2015-05-13

    This thesis demonstrates the applicability of far-infrared spectroscopy for the study of the crystal-field splitting of lanthanides in single-molecular magnetic materials. The far-infrared studies of three different kinds of single-molecular-magnetic materials, a single-ion magnet, a single-chain magnet and an exchange-coupled cluster, yielded a deeper understanding of the crystal-field splitting of the lanthanides in these materials. In addition, our results offered the opportunity to gain a deeper insight into the relaxation processes of these materials.

  7. Flux Calibration of Broadband Far Infrared and Submillimetre Photometric Instruments: Theory and Application to Herschel-SPIRE

    CERN Document Server

    Griffin, M J; Schulz, B; Amaral-Rogers, A; Bendo, G; Bock, J; Conley, A; Dowell, C D; Ferlet, M; Glenn, J; Lim, T; Pearson, C; Pohlen, M; Sibthorpe, B; Spencer, L; Swinyard, B; Valtchanov, I

    2013-01-01

    Photometric instruments operating at far infrared to millimetre wavelengths often have broad spectral passbands (central wavelength/bandwidth ~ 3 or less), especially those operating in space. A broad passband can result in significant variation of the beam profile and aperture efficiency across the passband, effects which thus far have not generally been taken into account in the flux calibration of such instruments. With absolute calibration uncertainties associated with the brightness of primary calibration standards now in the region of 5% or less, variation of the beam properties across the passband can be a significant contributor to the overall calibration accuracy for extended emission. We present a calibration framework which takes such variations into account for both antenna-coupled and absorber-coupled focal plane architectures. The scheme covers point source and extended source cases, and also the intermediate case of a semi-extended source profile. We apply the new method to the Herschel-SPIRE s...

  8. Far-infrared study of amorphous Ge{sub 0.17}Se{sub 0.83-x}Sb{sub x} chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Parikshit [Department of Physics, H.P. University, Summer Hill, Shimla 171005 (India)], E-mail: sharma_parikshit@yahoo.com; Rangra, V.S. [Department of Physics, H.P. University, Summer Hill, Shimla 171005 (India); Sharma, Pankaj [Department of Physics, Jaypee University of Information Technology, Waknaghat, Solan, H.P. 173215 (India)], E-mail: pankaj.sharma@juit.ac.in; Katyal, S.C. [Department of Physics, Jaypee University of Information Technology, Waknaghat, Solan, H.P. 173215 (India)

    2009-07-08

    Far-infrared transmission spectra of Ge{sub 0.17}Se{sub 0.83-x}Sb{sub x} (x = 0, 0.03, 0.09, 0.12, 0.15) glassy alloys are obtained in the spectral range 500-200 cm{sup -1} at room temperature. The results are interpreted in terms of the vibrations of the isolated molecular units, in such a way as to preserve fourfold and twofold coordination for Ge and Se atoms, respectively. In the Ge{sub 0.17}Se{sub 0.83} bulk glass the main absorption bands appear at {approx}250 cm{sup -1} and 300 cm{sup -1}. With the increase in Sb content some new bands start appearing at 228-231 cm{sup -1} and 250-260 cm{sup -1}. Theoretical calculations (bond energy, relative probability density of bond formation, force constant and wave number) were also made to justify the results.

  9. Galactic Synchrotron Emission and the Far-infrared-Radio Correlation at High Redshift

    Science.gov (United States)

    Schober, J.; Schleicher, D. R. G.; Klessen, R. S.

    2016-08-01

    Theoretical scenarios, including the turbulent small-scale dynamo, predict that strong magnetic fields already exist in young galaxies. Based on the assumption of energy equipartition between magnetic fields and turbulence, we determine the galactic synchrotron flux as a function of redshift z. Galaxies in the early universe are different from local galaxies, in particular, the former have more intense star formation. To cover a large range of conditions, we consider two different systems: one model galaxy comparable to the Milky Way and one typical high-z starburst galaxy. We include a model of the steady-state cosmic ray spectrum and find that synchrotron emission can be detected up to cosmological redshifts with current and future radio telescopes. The turbulent dynamo theory is in agreement with the origin of the observed correlation between the far-infrared (FIR) luminosity L FIR and the radio luminosity L radio. Our model reproduces this correlation well at z = 0. We extrapolate the FIR-radio correlation to higher redshifts and predict a time evolution with a significant deviation from its present-day appearance already at z≈ 2 for a gas density that increases strongly with z. In particular, we predict a decrease of the radio luminosity with redshift which is caused by the increase of cosmic ray energy losses at high z. The result is an increase of the ratio between L FIR and L radio. Simultaneously, we predict that the slope of the FIR-radio correlation becomes shallower with redshift. This behavior of the correlation could be observed in the near future with ultra-deep radio surveys.

  10. A Comparative Analysis of the Far Infrared Spectra of Saturn's Rings and Icy Satellites with Cassini CIRS

    Science.gov (United States)

    Brooks, Shawn M.; Spilker, Linda; Edgington, Scott G.

    2016-10-01

    We will report on a campaign to observe Saturn's main rings and major icy satellites with the Composite Infrared Spectrometer onboard Cassini. CIRS' three infrared detectors cover a combined spectral range of 10 to 1400 cm-1 (1 mm down to 7 microns). We focus on data from Focal Plane 1, which covers the 10 to 600 cm-1 range (1 mm to 16 microns). The apodized spectral resolution of the instrument can be varied from 15 cm-1 to 0.5 cm-1 (Flasar et al. 2004).The spectral behavior of Saturn's main rings and icy satellites in the far infrared has been the subject of previous studies with CIRS FP1 data (Spilker at al. 2005, Carvano et al. 2007, Morishima et al. 2012). These studies have shown that the infrared spectra of these icy rings and bodies are remarkably flat between about 40 to 200 microns. Longward of this, CIRS observations, as well as older spacecraft data, show a gradual decrease in ring emissivity. This roll-off in emissivity may be due to varying optical constants of water ice, which dominates the rings' composition, as one moves towards microwave wavelengths. Carvano et al. (2007), who analyzed spectra of the icy satellites Phoebe, Iapetus, Enceladus, Tethys and Hyperion, investigated the absence of emissivity features in spectra of those satellites. This absence is intriguing, as water ice, which dominates their surface composition, contains absorption features in the FP1 spectral range. They conclude that high porosity in these satellites' regoliths may explain this lack of spectral variability.To better characterize the far infrared spectra of the rings and satellites, we have implemented a series of dedicated observations. The goal is to obtain thousands of infrared spectra at 3 cm-1 resolution of each individual ring region and as many satellites as possible. We will have more spectra than Spilker et al. had for their work at a higher spectral resolution than in the analyses of Carvano et al. and Morishima et al. A preliminary analysis of these

  11. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: II. Extragalactic far infrared background radiation

    Science.gov (United States)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2014-07-01

    Using formula to describe the average spectrum of the extragalactic far infrared background (FIRB) radiation measured by the COBE FIRAS instrument in the 0.15-2.4 THz frequency interval at mean temperature T=18.5 K, the radiative and thermodynamic properties, such as the total emissivity, total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, and pressure are calculated. The value for the total intensity received in the 0.15-2.4 THz frequency interval is equal to 13.6 nW m-2 sr-1. This value is about 19.4 % of the total intensity expected from the energy released by stellar nucleosynthesis over cosmic history. The radiative and thermodynamic functions of the extragalactic far infrared background (FIRB) radiation are calculated at redshift z=1.5.

  12. ISO far-infrared observations of rich galaxy clusters II. Sersic 159-03

    DEFF Research Database (Denmark)

    Hansen, Lene; Jørgensen, H.E.; Nørgaard-Nielsen, Hans Ulrik

    2000-01-01

    In a series of papers we investigate far-infrared emission from rich galaxy clusters. Maps have been obtained by ISO at 60 mu m, 100 mu m, 135 mu m, and 200 mu m using the PHT-C camera. Ground based imaging and spectroscopy were also acquired. Here we present the results for the cooling flow...

  13. ISO far-infrared observations of rich galaxy clusters I. Abell 2670

    DEFF Research Database (Denmark)

    Hansen, Lene; Jorgensen, H.E.; Nørgaard-Nielsen, Hans Ulrik

    1999-01-01

    As part of an investigation of far-infrared emission from rich galaxy clusters the central part of Abell 2670 has been mapped with ISO at 60 mu m, 100 mu m, 135 mu m, and 200 mu m using the PHT-C camera. Point sources detected in the field have infrared fluxes comparable to normal spirals...

  14. Far-Infrared Study of the Charge Density Wave in Tetrathiofulvalene Tetracyanoquinodimethane (TTF-TCNQ)

    DEFF Research Database (Denmark)

    Tanner, D. B.; Cummings, K. D.; Jacobsen, Claus Schelde

    1981-01-01

    Detailed far-infrared measurements at temperatures from 25 to 300 K provide strong support for a charge-density-wave mechanism for the dc conductivity and microwave dielectric constant of tetrathiafulvalene tetracyanoquinodimethane (TTF-TCNQ). At low temperatures the charge-density wave is pinned...

  15. Isotopic labelling studies on far-infrared spectra of nickel-histamine complexes

    Science.gov (United States)

    Drożdżewski, Piotr; Kordon, Ewa

    2000-11-01

    Nickel-histamine (hm) complexes type [Ni(hm)Cl 2] and [Ni(hm) 3] X2 (Where X=Cl, Br, I, ClO 4) were investigated in the far-infrared region. Metal isotope labelling and deuteration effects were employed for observed band assignments. Metal-ligand vibrations were discussed and correlated with the structures of the complexes.

  16. The Far-Infrared Surveyor Mission study: paper I, the genesis

    NARCIS (Netherlands)

    Meixner, M.; Cooray, A.; Carter, R.; DiPirro, M.; Flores, A.; Leisawitz, D.; Armus, L.; Battersby, C.; Bergin, E.; Bradford, C. M.; Ennico, K.; Melnick, G. J.; Milam, S.; Narayanan, D.; Pontoppidan, K.; Pope, A.; Roellig, T.; Sandstrom, K.; Su, K. Y. L.; Vieira, J.; Wright, E.; Zmuidzinas, J.; Alato, S.; Carey, S.; Gerin, M.; Helmich, F.; Menten, K.; Scott, D.; Sakon, I.; Vavrek, R.

    2016-01-01

    This paper describes the beginning of the Far-Infrared Surveyor mission study for NASA's Astrophysics Decadal 2020. We describe the scope of the study, and the open process approach of the Science and Technology Definition Team. We are currently developing the science cases and provide some prelimin

  17. The Far-Infrared Surveyor Mission study: paper I, the genesis

    NARCIS (Netherlands)

    Meixner, M.; Cooray, A.; Carter, R.; DiPirro, M.; Flores, A.; Leisawitz, D.; Armus, L.; Battersby, C.; Bergin, E.; Bradford, C. M.; Ennico, K.; Melnick, G. J.; Milam, S.; Narayanan, D.; Pontoppidan, K.; Pope, A.; Roellig, T.; Sandstrom, K.; Su, K. Y. L.; Vieira, J.; Wright, E.; Zmuidzinas, J.; Alato, S.; Carey, S.; Gerin, M.; Helmich, F.; Menten, K.; Scott, D.; Sakon, I.; Vavrek, R.

    2016-01-01

    This paper describes the beginning of the Far-Infrared Surveyor mission study for NASA's Astrophysics Decadal 2020. We describe the scope of the study, and the open process approach of the Science and Technology Definition Team. We are currently developing the science cases and provide some

  18. Far infrared transmittance of Sc2@C84 and Er2@C82

    NARCIS (Netherlands)

    Grannan, S.M.; Birmingham, J.T.; Richards, P.L.; Bethune, D.S.; Vries, M.S. de; Loosdrecht, P.H.M. van; Dorn, H.C.; Burbank, P.; Bailey, J.; Stevenson, S.

    1997-01-01

    We have measured the far infrared transmittance of Sc2@C84 and Er2@C82 at 1.5 K between 30 and 200 cm-1. Both materials are observed to have a large primary absorption feature centered at 95 cm-1 with a width of approximately 50 cm-1, as well as a number of secondary absorption features which are di

  19. ISO far-infrared observations of rich galaxy clusters I. Abell 2670

    DEFF Research Database (Denmark)

    Hansen, Lene; Jorgensen, H.E.; Nørgaard-Nielsen, Hans Ulrik

    1999-01-01

    As part of an investigation of far-infrared emission from rich galaxy clusters the central part of Abell 2670 has been mapped with ISO at 60 mu m, 100 mu m, 135 mu m, and 200 mu m using the PHT-C camera. Point sources detected in the field have infrared fluxes comparable to normal spirals...

  20. ISO far-infrared observations of rich galaxy clusters II. Sersic 159-03

    DEFF Research Database (Denmark)

    Hansen, Lene; Jørgensen, H.E.; Nørgaard-Nielsen, Hans Ulrik

    2000-01-01

    In a series of papers we investigate far-infrared emission from rich galaxy clusters. Maps have been obtained by ISO at 60 mu m, 100 mu m, 135 mu m, and 200 mu m using the PHT-C camera. Ground based imaging and spectroscopy were also acquired. Here we present the results for the cooling flow...

  1. HERSCHEL FAR-INFRARED AND SUBMILLIMETER PHOTOMETRY FOR THE KINGFISH SAMPLE OF NEARBY GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Dale, D. A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Aniano, G.; Draine, B. T. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Engelbracht, C. W.; Hinz, J. L.; Montiel, E. J. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Krause, O.; Groves, B. A. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Roussel, H. [Institut d' Astrophysique de Paris, UMR7095 CNRS, Universite Pierre and Marie Curie, 98 bis Boulevard Arago, 75014 Paris (France); Appleton, P. N. [NASA Herschel Science Center, IPAC, California Institute of Technology, Pasadena, CA 91125 (United States); Armus, L.; Beirao, P. [Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States); Bolatto, A. D. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Brandl, B. R. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Calzetti, D.; Crocker, A. F. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Croxall, K. V. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Galametz, M. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Gordon, K. D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Hao, C.-N., E-mail: ddale@uwyo.edu [Tianjin Astrophysics Center, Tianjin Normal University, Tianjin 300387 (China); and others

    2012-01-20

    New far-infrared and submillimeter photometry from the Herschel Space Observatory is presented for 61 nearby galaxies from the Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel (KINGFISH) sample. The spatially integrated fluxes are largely consistent with expectations based on Spitzer far-infrared photometry and extrapolations to longer wavelengths using popular dust emission models. Dwarf irregular galaxies are notable exceptions, as already noted by other authors, as their 500 {mu}m emission shows evidence for a submillimeter excess. In addition, the fraction of dust heating attributed to intense radiation fields associated with photodissociation regions is found to be (21 {+-} 4)% larger when Herschel data are included in the analysis. Dust masses obtained from the dust emission models of Draine and Li are found to be on average nearly a factor of two higher than those based on single-temperature modified blackbodies, as single blackbody curves do not capture the full range of dust temperatures inherent to any galaxy. The discrepancy is largest for galaxies exhibiting the coolest far-infrared colors.

  2. An ISO far-infrared survey of line and continuum emission for 227 galaxies

    Science.gov (United States)

    Brauher, J. R.

    2002-01-01

    Far-infrared line and continuum fluxes are presented for a sample of 227 galaxies observed with the Long Wavelength Spectrometer on the Infrared Space Observatory, selected from the ISO Data Archive and having an IRAS 60/100 mu m color ration of 0.2-1.4 and IRAS 60 mu m flux density between 0.1 Jy and 1300 Jy.

  3. Galaxy And Mass Assembly: the evolution of the cosmic spectral energy distribution from z = 1 to z = 0

    Science.gov (United States)

    Andrews, S. K.; Driver, S. P.; Davies, L. J. M.; Kafle, P. R.; Robotham, A. S. G.; Vinsen, K.; Wright, A. H.; Bland-Hawthorn, J.; Bourne, N.; Bremer, M.; da Cunha, E.; Drinkwater, M.; Holwerda, B.; Hopkins, A. M.; Kelvin, L. S.; Loveday, J.; Phillipps, S.; Wilkins, S.

    2017-09-01

    We present the evolution of the cosmic spectral energy distribution (CSED) from z = 1 to 0. Our CSEDs originate from stacking individual spectral energy distribution (SED) fits based on panchromatic photometry from the Galaxy And Mass Assembly (GAMA) and COSMOS data sets in 10 redshift intervals with completeness corrections applied. Below z = 0.45, we have credible SED fits from 100 nm to 1 mm. Due to the relatively low sensitivity of the far-infrared data, our far-infrared CSEDs contain a mix of predicted and measured fluxes above z = 0.45. Our results include appropriate errors to highlight the impact of these corrections. We show that the bolometric energy output of the Universe has declined by a factor of roughly 4 - from 5.1 ± 1.0 at z ∼ 1 to 1.3 ± 0.3 × 1035 h70 W Mpc-3 at the current epoch. We show that this decrease is robust to cosmic sample variance, the SED modelling and other various types of error. Our CSEDs are also consistent with an increase in the mean age of stellar populations. We also show that dust attenuation has decreased over the same period, with the photon escape fraction at 150 nm increasing from 16 ± 3 at z ∼ 1 to 24 ± 5 per cent at the current epoch, equivalent to a decrease in AFUV of 0.4 mag. Our CSEDs account for 68 ± 12 and 61 ± 13 per cent of the cosmic optical and infrared backgrounds, respectively, as defined from integrated galaxy counts and are consistent with previous estimates of the cosmic infrared background with redshift.

  4. The Herschel Orion Protostar Survey: Spectral Energy Distributions and Fits Using a Grid of Protostellar Models

    CERN Document Server

    Furlan, E; Ali, B; Stutz, A M; Stanke, T; Tobin, J J; Megeath, S T; Osorio, M; Hartmann, L; Calvet, N; Poteet, C A; Booker, J; Manoj, P; Watson, D M; Allen, L

    2016-01-01

    We present key results from the Herschel Orion Protostar Survey (HOPS): spectral energy distributions (SEDs) and model fits of 330 young stellar objects, predominantly protostars, in the Orion molecular clouds. This is the largest sample of protostars studied in a single, nearby star-formation complex. With near-infrared photometry from 2MASS, mid- and far-infrared data from Spitzer and Herschel, and sub-millimeter photometry from APEX, our SEDs cover 1.2-870 $\\mu$m and sample the peak of the protostellar envelope emission at ~100 $\\mu$m. Using mid-IR spectral indices and bolometric temperatures, we classify our sample into 92 Class 0 protostars, 125 Class I protostars, 102 flat-spectrum sources, and 11 Class II pre-main-sequence stars. We implement a simple protostellar model (including a disk in an infalling envelope with outflow cavities) to generate a grid of 30400 model SEDs and use it to determine the best-fit model parameters for each protostar. We argue that far-IR data are essential for accurate cons...

  5. Laboratory microwave, millimeter wave and far-infrared spectra of dimethyl sulfide

    Science.gov (United States)

    Jabri, A.; Van, V.; Nguyen, H. V. L.; Mouhib, H.; Kwabia Tchana, F.; Manceron, L.; Stahl, W.; Kleiner, I.

    2016-05-01

    Context. Dimethyl sulfide, CH3SCH3 (DMS), is a nonrigid, sulfur-containing molecule whose astronomical detection is considered to be possible in the interstellar medium. Very accurate spectroscopic constants were obtained by a laboratory analysis of rotational microwave and millimeter wave spectra, as well as rotation-torsional far-infrared (FIR) spectra, which can be used to predict transition frequencies for a detection in interstellar sources. Aims: This work aims at the experimental study and theoretical analysis of the ground torsional state and ground torsional band ν15 of DMS in a large spectral range for astrophysical use. Methods: The microwave spectrum was measured in the frequency range 2-40 GHz using two Molecular Beam Fourier Transform MicroWave (MB-FTMW) spectrometers in Aachen, Germany. The millimeter spectrum was recorded in the 50-110 GHz range. The FIR spectrum was measured for the first time at high resolution using the FT spectrometer and the newly built cryogenic cell at the French synchrotron SOLEIL. Results: DMS has two equivalent methyl internal rotors with a barrier height of about 730 cm-1. We performed a fit, using the XIAM and BELGI-Cs-2Tops codes, that contained the new measurements and previous transitions reported in the literature for the ground torsional state νt = 0 (including the four torsional species AA, AE, EA and EE) and for the ground torsional band ν15 = 1 ← 0 (including only the AA species). In the microwave region, we analyzed 584 transitions with J ≤ 30 of the ground torsional state νt = 0 and 18 transitions with J ≤ 5 of the first excited torsional state νt = 1. In the FIR range, 578 transitions belonging to the torsional band ν15 = 1 ← 0 with J ≤ 27 were assigned. Totally, 1180 transitions were included in a global fit with 21 accurately determined parameters. These parameters can be used to produce a reliable line-list for an astrophysical detection of DMS. Full Tables B.1 and C.1, and Table E.1 are

  6. Far infrared radiation promotes rabbit renal proximal tubule cell proliferation and functional characteristics, and protects against cisplatin-induced nephrotoxicity.

    Science.gov (United States)

    Chiang, I-Ni; Pu, Yeong-Shiau; Huang, Chao-Yuan; Young, Tai-Horng

    2017-01-01

    Far infrared radiation, a subdivision of the electromagnetic spectrum, is beneficial for long-term tissue healing, anti-inflammatory effects, growth promotion, sleep modulation, acceleration of microcirculation, and pain relief. We investigated if far infrared radiation is beneficial for renal proximal tubule cell cultivation and renal tissue engineering. We observed the effects of far infrared radiation on renal proximal tubules cells, including its effects on cell proliferation, gene and protein expression, and viability. We also examined the protective effects of far infrared radiation against cisplatin, a nephrotoxic agent, using the human proximal tubule cell line HK-2. We found that daily exposure to far infrared radiation for 30 min significantly increased rabbit renal proximal tubule cell proliferation in vitro, as assessed by MTT assay. Far infrared radiation was not only beneficial to renal proximal tubule cell proliferation, it also increased the expression of ATPase Na+/K+ subunit alpha 1 and glucose transporter 1, as determined by western blotting. Using quantitative polymerase chain reaction, we found that far infrared radiation enhanced CDK5R1, GNAS, NPPB, and TEK expression. In the proximal tubule cell line HK-2, far infrared radiation protected against cisplatin-mediated nephrotoxicity by reducing apoptosis. Renal proximal tubule cell cultivation with far infrared radiation exposure resulted in better cell proliferation, significantly higher ATPase Na+/K+ subunit alpha 1 and glucose transporter 1 expression, and significantly enhanced expression of CDK5R1, GNAS, NPPB, and TEK. These results suggest that far infrared radiation improves cell proliferation and differentiation. In HK-2 cells, far infrared radiation mediated protective effects against cisplatin-induced nephrotoxicity by reducing apoptosis, as indicated by flow cytometry and caspase-3 assay.

  7. Far-infrared reflectivity spectra of the hydrogen-bonded ferroelectric KH[sub 2]PO[sub 4] measured by synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Shik; Tezuka, Yasuhisa (Tokyo Univ. (Japan). Inst. for Solid State Physics); Saito, Shinji; Chiba, Yuki; Ishigame, Mareo

    1994-07-01

    Far infrared reflectivity spectra of hydrogen-bonded ferroelectric KH[sub 2]PO[sub 4] are measured by using synchrotron radiation in the photon-energy region from 5 to 250 cm[sup -1]. The strong relaxational mode is found in the infrared spectra. This result is consistent with the results which have been obtained by the hyper-Raman and Raman scattering, but inconsistent with the results which have been observed by the ordinary infrared light source. (author).

  8. Low-Energy Spectral Features in GRBs

    CERN Document Server

    Briggs, M S

    1996-01-01

    I discuss low-energy lines in gamma-ray bursts. The process of deconvolving gamma-ray spectral data and the steps needed to demonstrate the existence of a line are explained. Previous observations and the current status of the analysis of the BATSE data are described.

  9. A BAYESIAN METHOD FOR THE ANALYSIS OF THE DUST EMISSION IN THE FAR-INFRARED AND SUBMILLIMETER

    Energy Technology Data Exchange (ETDEWEB)

    Veneziani, M.; Noriega-Crespo, A.; Carey, S.; Paladini, R. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Piacentini, F. [Dipartimento di Fisica, Universita di Roma ' ' La Sapienza' ' , I-00185 Rome (Italy); Paradis, D., E-mail: marcella.veneziani@ipac.caltech.edu [Universite de Toulouse, UPS-OMP, IRAP, F-31062 Toulouse (France)

    2013-07-20

    We present a method, based on Bayesian statistics, to fit the dust emission parameters in the far-infrared and submillimeter wavelengths. The method estimates the dust temperature and spectral emissivity index, plus their relationship, properly taking into account the statistical and systematic uncertainties. We test it on three sets of simulated sources detectable by the Herschel Space Observatory in the PACS and SPIRE spectral bands (70-500 {mu}m), spanning over a wide range of dust temperatures. The simulated observations are a one-component interstellar medium and two two-component sources, both warm (H II regions) and cold (cold clumps (CCs)). We first define a procedure to identify the better model, then we recover the parameters of the model and measure their physical correlations by means of a Markov Chain Monte Carlo algorithm adopting multi-variate Gaussian priors. In this process, we assess the reliability of the model recovery and of parameter estimation. We conclude that the model and parameters are properly recovered only under certain circumstances and that false models may be derived in some cases. We applied the method to a set of 91 starless CCs in an interarm region of the Galactic plane with low star formation activity, observed by Herschel in the Hi-GAL survey. Our results are consistent with a temperature-independent spectral index.

  10. Motivation and Prospects for Spatio-spectral Interferometry in the Far-infrared

    Science.gov (United States)

    Leisawitz, David

    2013-01-01

    Consensus developed through a series of workshops, starting in 1998. Compelling science case for high angular resolution imaging and spectroscopy, and mission concepts. A robust plan - it has evolved over the years, but has consistently called for high resolution.

  11. 光泵浦远红外气体激光器的研究发展%Research and development for optically pumped far-infrared gas laser

    Institute of Scientific and Technical Information of China (English)

    曲彦臣; 陈惠颖; 耿利杰; 赵卫疆

    2014-01-01

    远红外激光具有穿透性强、光子能量低、带宽宽、通信传输容量大等优点,在公共安全、环境探测、生物医学、天文观测、军事以及通信等方面得到了广泛应用。在介绍了远红外波段激光器发展的基础之上,对产生远红外激光的各种方式进行了对比分析和总结,讨论了光泵浦远红外气体激光器的技术优势,并针对近年来远红外激光工作介质及其新谱线进行了归纳。通过对连续和脉冲光泵浦远红外气体激光器发展的回顾,结合该领域的一些重点研究方向,给出了未来光泵浦远红外气体激光器的研究趋势。%Far infrared laser sources have many properties of strong penetration, low photon energy, wide bandwidth, large transmission capacity of communication, have been widely applications in public security, environmental monitoring, biomedical diagnostics, astronomical observation, military and communicational application, etc. The technological advantages of the optically pumped far infrared gas laser were gave by comparing a variety of ways to produce far infrared laser based on introducing their development. Summarized far-infrared laser mediums and their new lines of the recent years. At last, the research trends of optically pumped far infrared which were summarized by reviewing the continuous and pulsed optically pumped far-infrared gas laser development, combining with some of the key research directions in this field were indicated.

  12. Inhibition of water activated by far infrared functional ceramics on proliferation of hepatoma cells.

    Science.gov (United States)

    Zhang, Dongmei; Liang, Jinsheng; Ding, Yan; Meng, Junping; Zhang, Guangchuan

    2014-05-01

    Rare earth (RE)/tourmaline composite materials prepared by the precipitation method are added to the ceramic raw materials at a certain percentage and sintered into RE functional ceramics with high far infrared emission features. Then the far infrared functional ceramics are used to interact with water. The influence of the ceramics on the physical parameters of water is investigated, and the effect of the activated water on the growth of Bel-7402 hepatoma cells cultured in vitro is further studied. The results indicate that, compared with the raw water, the water activated by the ceramics can inhibit the proliferation of hepatoma cells, with statistical probability P ceramics has a higher concentration of H+, which decreases the potential difference across the cell membrane to release the apoptosis inducing factor (AIF). After entering the cells, the activated water stimulates the mitochondria to produce immune substances that lead tumor cells to apoptosis.

  13. Far-infrared Detection of C3 in Sagittarius B2 and IRC +10216.

    Science.gov (United States)

    Cernicharo; Goicoechea; Caux

    2000-05-10

    We report on the detection of nine lines of the nu2 bending mode of triatomic carbon, C3, in the direction of Sagittarius B2. The R(4) and R(2) lines of C3 have been also detected in the carbon-rich star IRC +10216. The abundances of C3 in the direction of Sgr B2 and IRC +10216 are approximately 3x10-8 and approximately 10-6, respectively. In Sgr B2 we have also detected the 23-12 line of NH with an abundance of a few times 10-9. Polyatomic molecules will have a weak contribution from their pure rotational spectrum to the emission/absorption in the far-infrared. We suggest, however, that they could be, through their low-lying vibrational bending modes, the dominant carriers of emission/absorption in the spectrum of bright far-infrared sources.

  14. Far-infrared amide IV-VI spectroscopy of isolated 2- and 4-Methylacetanilide

    Science.gov (United States)

    Yatsyna, Vasyl; Bakker, Daniël J.; Feifel, Raimund; Rijs, Anouk M.; Zhaunerchyk, Vitali

    2016-09-01

    Delocalized molecular vibrations in the far-infrared and THz ranges are highly sensitive to the molecular structure, as well as to intra- and inter-molecular interactions. Thus, spectroscopic studies of biomolecular structures can greatly benefit from an extension of the conventional mid-infrared to the far-infrared wavelength range. In this work, the conformer-specific gas-phase far-infrared spectra of two aromatic molecules containing the peptide -CO-NH- link, namely, 2- and 4-Methylacetanilide, are investigated. The planar conformations with trans configuration of the peptide link have only been observed in the supersonic-jet expansion. The corresponding far-infrared signatures associated with the vibrations of the peptide -CO-NH- moiety, the so-called amide IV-VI bands, have been assigned and compared with the results of density functional theory frequency calculations based on the anharmonic vibrational second-order perturbation theory approach. The analysis of the experimental and theoretical data shows that the amide IV-VI bands are highly diagnostic for the geometry of the peptide moiety and the molecular backbone. They are also strongly blue-shifted upon formation of the NH⋯O-C hydrogen bonding, which is, for example, responsible for the formation of secondary protein structures. Furthermore, the amide IV-VI bands are also diagnostic for the cis configuration of the peptide link, which can be present in cyclic peptides. The experimental gas-phase data presented in this work can assist the vibrational assignment of similar biologically important systems, either isolated or in natural environments.

  15. Far-Infrared Polarimetry of Galactic Clouds from the Kuiper Airborne Observatory

    Science.gov (United States)

    Dotson, Jessie L.; Davidson, Jacqueline; Dowell, C. Darren; Schleuning, David A.; Hildebrand, Roger H.

    1999-01-01

    In this paper we present a complete summary of the data obtained with the far-infrared polarimeter, Stokes, in flights of the Kuiper Airborne Observatory. We have observed 12 Galactic clouds and have made over 1100 individual measurements at 100 micrometer and 60 micrometer. The median P for all of the 60 micrometer and 100 micrometer measurements is 3.6% and 2.6% respectively. We also present flux maps obtained simultaneously with the polarimetry.

  16. Variable-delay Polarization Modulators (VPMs) for Far-infrared through Millimeter Astronomy

    Science.gov (United States)

    Chuss, David T.

    2008-01-01

    This viewgraph presentation reviews the use of Variable-delay Polarization Modulators (VPMs) for Far-infrared through Millimeter Astronomy. The two science goals are to use polarized emission from the partially-aligned dust that provides a probe of the role of magnetic fields in star formation and to use the polarization of the cosmic microwave background radiation CMB to test theories of the very early universe and provide a probe of fundamental physics.

  17. FIRBACK Far Infrared Survey with ISO Data Reduction, Analysis and First Results

    CERN Document Server

    Dole, H; Puget, J L; Aussel, H; Bouchet, F R; Ciliegi, C; Clements, D L; Césarsky, C J; Désert, F X; Elbaz, D; Franceschini, A; Gispert, R; Guiderdoni, B; Harwit, M; Laureijs, R J; Lemke, D; McMahon, R; Moorwood, A F M; Oliver, S; Reach, W T; Rowan-Robinson, M; Stickel, M; Dole, Herve; Lagache, Guilaine; Puget, Jean-Loup

    1999-01-01

    FIRBACK is one of the deepest cosmological surveys performed in the far infrared, using ISOPHOT. We describe this survey, its data reduction and analysis. We present the maps of fields at 175 microns. We point out some first results: source identifications with radio and mid infrared, and source counts at 175 microns. These two results suggest that half of the FIRBACK sources are probably at redshifts greater than 1. We also present briefly the large follow-up program.

  18. Waveguide design for mid- and far-infrared p-Si/SiGe quantum cascade lasers

    Science.gov (United States)

    Ikonic, Z.; Kelsall, R. W.; Harrison, P.

    2004-01-01

    Design considerations are presented for waveguides to be used in p-Si/SiGe based quantum cascade lasers operating in the mid- and far-infrared wavelength ranges. Modal losses and confinement factors are calculated for both TM and TE modes in conventional double metal clad structures, metal-highly doped semiconductor layer structures and also in novel metal-metal silicide structures. Guidelines for choosing the confinement and contact layer parameters are given.

  19. Far infrared and submillimetre surveys: from IRAS to Akari, Herschel and Planck

    CERN Document Server

    Rowan-Robinson, Michael

    2015-01-01

    We discuss a new IRAS Faint Source Catalog galaxy redshift catalogue (RIFSCz) which incorporates data from Galex, SDSS, 2MASS, WISE, Akari and Planck. Akari fluxes are consistent with photometry from other far infrared and submillimetre missions provided an aperture correction is applied. Results from the Hermes-SWIRE survey in Lockman are also discussed briefly, and the strong contrast between the galaxy populations selected at 60 and 500 mu is summarized.

  20. The Far-Infrared Emission Line and Continuum Spectrum of the Seyfert Galaxy NGC 1068

    Science.gov (United States)

    2005-04-10

    THE FAR-INFRARED EMISSION LINE AND CONTINUUM SPECTRUM OF THE SEYFERT GALAXY NGC 10681 Luigi Spinoglio Istituto di Fisica dello Spazio Interplanetario...circumnuclear ring of 1500–1600 in radius within the last 4–40 Myr. CO interferometer observa- tions revealed molecular gas very close to the nucleus...from 43 to 197 m showing both atomic and molecular emission lines (x 2). We model the composite UV to far-IR atomic emission-line and continuum

  1. Atomic oxygen fine-structure splittings with tunable far-infrared spectroscopy

    Science.gov (United States)

    Zink, Lyndon R.; Evenson, Kenneth M.; Matsushima, Fusakazu; Nelis, Thomas; Robinson, Ruth L.

    1991-01-01

    Fine-structure splittings of atomic oxygen (O-16) in the ground state have been accurately measured using a tunable far-infrared spectrometer. The 3P0-3pl splitting is 2,060,069.09 (10) MHz, and the 3Pl-3P2 splitting is 4,744,777.49 (16) MHz. These frequencies are important for measuring atomic oxygen concentration in earth's atmosphere and the interstellar medium.

  2. Far-infrared amide IV-VI spectroscopy of isolated 2- and 4-Methylacetanilide.

    Science.gov (United States)

    Yatsyna, Vasyl; Bakker, Daniël J; Feifel, Raimund; Rijs, Anouk M; Zhaunerchyk, Vitali

    2016-09-14

    Delocalized molecular vibrations in the far-infrared and THz ranges are highly sensitive to the molecular structure, as well as to intra- and inter-molecular interactions. Thus, spectroscopic studies of biomolecular structures can greatly benefit from an extension of the conventional mid-infrared to the far-infrared wavelength range. In this work, the conformer-specific gas-phase far-infrared spectra of two aromatic molecules containing the peptide -CO-NH- link, namely, 2- and 4-Methylacetanilide, are investigated. The planar conformations with trans configuration of the peptide link have only been observed in the supersonic-jet expansion. The corresponding far-infrared signatures associated with the vibrations of the peptide -CO-NH- moiety, the so-called amide IV-VI bands, have been assigned and compared with the results of density functional theory frequency calculations based on the anharmonic vibrational second-order perturbation theory approach. The analysis of the experimental and theoretical data shows that the amide IV-VI bands are highly diagnostic for the geometry of the peptide moiety and the molecular backbone. They are also strongly blue-shifted upon formation of the NH⋯O-C hydrogen bonding, which is, for example, responsible for the formation of secondary protein structures. Furthermore, the amide IV-VI bands are also diagnostic for the cis configuration of the peptide link, which can be present in cyclic peptides. The experimental gas-phase data presented in this work can assist the vibrational assignment of similar biologically important systems, either isolated or in natural environments.

  3. a Self-Consistent Analysis of Far-Infrared and Submillimeter Wavelength Metal-Grating Free Electron Lasers.

    Science.gov (United States)

    Xu, Yansun

    A theoretical exploration of the characteristics and operational requirements of far-infrared and sub-millimeter wavelength Metal-Grating Free-Electron-Lasers is presented. In the device an open planar type of quasi-optical resonator is loaded with a strip of rectangular metal-grating, and driven by a moderate energy electron beam. The basic tuning features and energy storage capacity of the resonator are described by the dispersion relation of the periodic slow -wave structure. To give a complete description of electron and wave dynamics in the laser oscillator, a set of self -consistent equations are derived through the use of the Lorentz force equation and the Maxwell's equations. Small signal gain and output efficiency of the device are developed from the self-consistent model. The nonlinear saturation is examined with a strong-field technique which is based upon a simple nonlinear ordinary differential equation of Duffing type. A detailed evaluation of the start-current, optimum interaction length and output efficiency of the laser oscillator at far-infrared and sub-millimeter wavelength region, indicates that the operations at wavelengths from 1mm to 100mum could be optimized at the output efficiencies around 1% with the use of an 100keV to 1MeV electron beam of current densities from 10 to 100(A/cm{^2}) and a 10 to 20cm long grating section. A theory of klystron type Metal-Grating Free Electron Lasers is also developed. Results of the proof-of-principle tests in the lower-millimeter wavelength region show that the klystron type devices generate more coherent radiations with start-current below 0.5A, and output power and efficiency up to 600watts and 2% at about 35GHz.

  4. Effect of Tourmaline-Doped on the Far Infrared Emission of Iron Ore Tailings Ceramics.

    Science.gov (United States)

    Liu, Jie; Meng, Junping; Liang, Jinsheng; Zhang, Hongchen; Gu, Xiaoyang

    2016-04-01

    Iron ore tailings as secondary resources have been of great importance to many countries in the world. Their compositions are similar to that of infrared emission ceramics, but there are few reports about it. In addition, tourmaline has high infrared emission properties due to its unique structure. With the purpose of expanding functional utilization of iron ore tailings, as well as reducing the production cost of far infrared ceramics, a new kind of far infrared emission ceramics was prepared by using iron ore tailings, calcium carbonate, silica, and natural tourmaline. The ceramics powders were characterized by Fourier transform infrared spectroscope, X-ray diffraction and scanning electron microscopy, respectively. The results show that after being sintered at 1065 °C, the percentage of pseudobrookite and lattice strain of samples increased with increasing the elbaite content. Furthermore, the added tourmaline was conducive to the densification sintering of ceramics. The appearance of Li-O vibration at 734.73 cm-1, as well as the strengthened Fe-O vibration at 987.68 cm-1 were attributed to the formation of Li0.375Fe1.23Ti1.4O5 solid solution, which led the average far infrared emissivity of ceramics increase from 0.861 to 0.906 within 8-14 µm.

  5. Far infrared emitting plaster in knee osteoarthritis: a single blinded, randomised clinical trial

    Directory of Open Access Journals (Sweden)

    N. Marino

    2012-12-01

    Full Text Available Objective. Therapeutic approach of osteoarthritis (OA still represents a challenge in clinical practice. The aim of the study is to assess the efficacy of far infrared (FIR emitting plaster in the treatment of knee OA. Design. This is a randomized, single-blind, placebo-controlled, parallel group with equal randomization (1:1, clinical trial. Patients affected by knee OA were randomly allocated to 1 of 2 treatment groups, either placebo plaster or far infrared emitting plaster. Primary endpoint was to assess pain improvement from baseline to 1 months posttreatment in the visual analogue score (VAS. Secondary end point was to evaluate pain score after 1 week of treatment and to compare ultrasonographic findings after 1 month of treatment. Results. Each group comprised 30 (in the FIR group and 30 (in the placebo group completers. VAS scores of the placebo and the FIR group were significantly lower at 1 week post-treatment (95% confidence interval CI = -1.14 to 0.31; PConclusions. Far infrared emitting plaster could be considered an effective non-pharmacological choice for the therapeutic management of knee OA.

  6. Fourier-transform far-infrared spectroscopic ellipsometry for standoff material identification

    Energy Technology Data Exchange (ETDEWEB)

    Ortolani, Michele, E-mail: michele.ortolani@ifn.cnr.i [Consiglio Nazionale delle Ricerche, Istituto di Fotonica e Nanotecnologie, Via Cineto Romano 42, I-00156 Rome (Italy); Schade, Ulrich [Helmholtz Zentrum Berlin fuer Materialen und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin (Germany)

    2010-11-11

    The ellipsometry is an efficient method to determine the optical properties of matter. It has been largely employed with grating spectrometers in the visible, UV and near-infrared ranges for the characterization of thin films, surfaces and interfaces. In the mid- and far-infrared, where most substance-specific absorption lines are present, spectroscopic ellipsometry with Fourier-transform spectrometers is still not extended as a routine method. In particular, the lack of powerful sources in the far-infrared/terahertz range has prevented standoff application of this method. We will show that it is possible to measure the complex dielectric constant of a solid in the far-infrared and terahertz range by a reflection experiment with polarized light and ellipsometric analysis with a suitable calibration procedure. Extraction of terahertz synchrotron radiation from storage rings provides a suitable source for research-grade experiments. The optical constants determined by ellipsometry compare well with those obtained by Kramers-Kronig procedures, a method which, however, requires broader frequency range and absolute reflectance standard. We will present the case of remote spectroscopic identification of explosive materials, which is relevant for forthcoming security applications.

  7. Herschel Far-Infrared and Sub-millimeter Photometry for the KINGFISH Sample of Nearby Galaxies

    CERN Document Server

    Dale, D A; Engelbracht, C W; Hinz, J L; Krause, O; Montiel, E J; Roussel, H; Appleton, P N; Armus, L; Beirao, P; Bolatto, A D; Brandl, B R; Calzetti, D; Crocker, A F; Croxall, K V; Draine, B T; Galametz, M; Gordon, K D; Groves, B A; Hao, C -N; Helou, G; Hunt, L K; Johnson, B D; Kennicutt, R C; Koda, J; Leroy, A K; Li, Y; Meidt, S E; Miller, A E; Murphy, E J; Rahman, N; Rix, H -W; Sandstrom, K M; Sauvage, M; Schinnerer, E; Skibba, R A; Smith, J -D T; Tabatabaei, F S; Walter, F; Wilson, C D; Wolfire, M G; Zibetti, S

    2011-01-01

    New far-infrared and sub-millimeter photometry from the Herschel Space Observatory is presented for 61 nearby galaxies from the Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel (KINGFISH) sample. The spatially-integrated fluxes are largely consistent with expectations based on Spitzer far-infrared photometry and extrapolations to longer wavelengths using popular dust emission models. Dwarf irregular galaxies are notable exceptions, as already noted by other authors, as their 500um emission shows evidence for a sub-millimeter excess. In addition, the fraction of dust heating attributed to intense radiation fields associated with photo-dissociation regions is found to be (21+/-4)% larger when Herschel data are included in the analysis. Dust masses obtained from the dust emission models of Draine & Li are found to be on average nearly a factor of two higher than those based on single-temperature modified blackbodies, as single blackbody curves do not capture the full range of dust tempera...

  8. Assignment of Infrared and Far-Infrared Transitions of CH2CF2

    Institute of Scientific and Technical Information of China (English)

    刘煜炎; 黄光明; 石丽华; 段传喜

    2002-01-01

    Starting from the Watson A-reduced Hamiltonian and considering the infrared transitions with ΔKa = 0, Δ Kc =±1 (A-type) or ΔKα = ±1, ΔKc = ±1 (B-type), and the far-infrared transitions with ΔKa = 0,±2 and ΔKc = ±1, we calculate all the possible infrared absorption and far-infrared emission transitions of the v4and v9 bands of 1,1-difluoroethylene (CH2CF2) pumped by 10P10 and 10P12 C02 laser lines. We assign four previously unassigned CH2CF2 far-infrared laser lines (291.3μm, 339.3μm, 349.5μm and 657.9μm), where Kaand Kc represent the quantum number K of the limiting prolate top and the limiting oblate top, respectively.The 291.3μm line is identified as being generated from the cascade transition. The assignment of the 288.5μm line by Lafferty et al. (J. Mol. Spectrosc. 87(1981)416) is also confirmed.

  9. Efficacy and safety of far infrared radiation in lymphedema treatment: clinical evaluation and laboratory analysis.

    Science.gov (United States)

    Li, Ke; Zhang, Zheng; Liu, Ning Fei; Feng, Shao Qing; Tong, Yun; Zhang, Ju Fang; Constantinides, Joannis; Lazzeri, Davide; Grassetti, Luca; Nicoli, Fabio; Zhang, Yi Xin

    2017-01-26

    Swelling is the most common symptom of extremities lymphedema. Clinical evaluation and laboratory analysis were conducted after far infrared radiation (FIR) treatment on the main four components of lymphedema: fluid, fat, protein, and hyaluronan. Far infrared radiation is a kind of hyperthermia therapy with several and additional benefits as well as promoting microcirculation flow and improving collateral lymph circumfluence. Although FIR therapy has been applied for several years on thousands of lymphedema patients, there are still few studies that have reported the biological effects of FIR on lymphatic tissue. In this research, we investigate the effects of far infrared rays on the major components of lymphatic tissue. Then, we explore the effectiveness and safety of FIR as a promising treatment modality of lymphedema. A total of 32 patients affected by lymphedema in stage II and III were treated between January 2015 and January 2016 at our department. After therapy, a significant decrease of limb circumference measurements was noted and improving of quality of life was registered. Laboratory examination showed the treatment can also decrease the deposition of fluid, fat, hyaluronan, and protein, improving the swelling condition. We believe FIR treatment could be considered as both an alternative monotherapy and a useful adjunctive to the conservative or surgical lymphedema procedures. Furthermore, the real and significant biological effects of FIR represent possible future applications in wide range of the medical field.

  10. Spectral Energy Distribution Mapping of Two Elliptical Galaxies on Sub-kpc Scales

    Science.gov (United States)

    Amblard, A.; Temi, P.; Gaspari, M.; Brighenti, F.

    2017-01-01

    We use high-resolution Herschel-PACS data of two nearby elliptical galaxies, IC 1459 and NGC 2768, to characterize their dust and stellar content. IC 1459 and NGC 2768 have an unusually large amount of dust for elliptical galaxies ((1–3) × 105 {M}ȯ ); this dust is also not distributed along the stellar content. Using data from GALEX (ultra-violet) to PACS (far-infrared, FIR), we analyze the spectral energy distribution (SED) of these galaxies with CIGALEMC as a function of the projected position, binning images in 7.″2 pixels. From this analysis, we derive maps of SED parameters, such as the metallicity, the stellar mass, the fraction of young stars, and the dust mass. The larger amount of dust in FIR maps seems related in our model to a larger fraction of young stars which can reach up to 4% in the dustier area. The young stellar population is fitted as a recent (∼0.5 Gyr) short burst of star formation for both galaxies. The metallicities, which are fairly large at the center of both galaxies, decrease with the radial distance with a fairly steep gradient for elliptical galaxies.

  11. Spectral Energy Distribution Mapping of Two Elliptical Galaxies on sub-kpc scales

    CERN Document Server

    Amblard, Alexandre; Gaspari, Massimo; Brighenti, Fabrizio

    2016-01-01

    We use high-resolution Herschel-PACS data of 2 nearby elliptical galaxies, IC1459 & NGC2768 to characterize their dust and stellar content. IC1459 & NGC2768 have an unusually large amount of dust for elliptical galaxies (1-3 x 10^5 Msun), this dust is also not distributed along the stellar content. Using data from GALEX (ultraviolet) to PACS (far-infrared), we analyze the spectral energy distribution (SED) of these galaxies with CIGALEMC as a function of the projected position, binning images in 7.2" pixels. From this analysis, we derive maps of SED parameters, such as the metallicity, the stellar mass, the fraction of young star and the dust mass. The larger amount of dust in FIR maps seems related in our model to a larger fraction of young stars which can reach up to 4% in the dustier area. The young stellar population is fitted as a recent (~ 0.5 Gyr) short burst of star formation for both galaxies. The metallicities, which are fairly large at the center of both galaxies, decrease with the radial d...

  12. HERschel key program heritage: A far-infrared source catalog for the Magellanic Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Seale, Jonathan P.; Meixner, Margaret; Sewiło, Marta [The Johns Hopkins University, Department of Physics and Astronomy, 366 Bloomberg Center, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Babler, Brian [Department of Astronomy, 475 North Charter St., University of Wisconsin, Madison, WI 53706 (United States); Engelbracht, Charles W.; Misselt, Karl; Montiel, Edward [Steward Observatory, University of Arizona, 933 North Cherry Ave., Tucson, AZ 85721 (United States); Gordon, Karl; Roman-Duval, Julia [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Hony, Sacha; Okumura, Koryo; Panuzzo, Pasquale; Sauvage, Marc [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Boyer, Martha L. [Observational Cosmology Laboratory, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Chen, C.-H. Rosie [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Indebetouw, Remy [National Radio Astronomy Observatory, 520 Edgemont Road Charlottesville, VA 22903 (United States); Matsuura, Mikako [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Oliveira, Joana M.; Loon, Jacco Th. van [School of Physical and Geographical Sciences, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG (United Kingdom); Srinivasan, Sundar [UPMC-CNRS UMR7095, Institute d' Astrophysique de Paris, F-75014 Paris (France); and others

    2014-12-01

    Observations from the HERschel Inventory of the Agents of Galaxy Evolution (HERITAGE) have been used to identify dusty populations of sources in the Large and Small Magellanic Clouds (LMC and SMC). We conducted the study using the HERITAGE catalogs of point sources available from the Herschel Science Center from both the Photodetector Array Camera and Spectrometer (PACS; 100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE; 250, 350, and 500 μm) cameras. These catalogs are matched to each other to create a Herschel band-merged catalog and then further matched to archival Spitzer IRAC and MIPS catalogs from the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and SAGE-SMC surveys to create single mid- to far-infrared (far-IR) point source catalogs that span the wavelength range from 3.6 to 500 μm. There are 35,322 unique sources in the LMC and 7503 in the SMC. To be bright in the FIR, a source must be very dusty, and so the sources in the HERITAGE catalogs represent the dustiest populations of sources. The brightest HERITAGE sources are dominated by young stellar objects (YSOs), and the dimmest by background galaxies. We identify the sources most likely to be background galaxies by first considering their morphology (distant galaxies are point-like at the resolution of Herschel) and then comparing the flux distribution to that of the Herschel Astrophysical Terahertz Large Area Survey (ATLAS) survey of galaxies. We find a total of 9745 background galaxy candidates in the LMC HERITAGE images and 5111 in the SMC images, in agreement with the number predicted by extrapolating from the ATLAS flux distribution. The majority of the Magellanic Cloud-residing sources are either very young, embedded forming stars or dusty clumps of the interstellar medium. Using the presence of 24 μm emission as a tracer of star formation, we identify 3518 YSO candidates in the LMC and 663 in the SMC. There are far fewer far-IR bright YSOs in the SMC than the LMC

  13. Herschel Key Program Heritage: a Far-Infrared Source Catalog for the Magellanic Clouds

    Science.gov (United States)

    Seale, Jonathan P.; Meixner, Margaret; Sewiło, Marta; Babler, Brian; Engelbracht, Charles W.; Gordon, Karl; Hony, Sacha; Misselt, Karl; Montiel, Edward; Okumura, Koryo; Panuzzo, Pasquale; Roman-Duval, Julia; Sauvage, Marc; Boyer, Martha L.; Chen, C.-H. Rosie; Indebetouw, Remy; Matsuura, Mikako; Oliveira, Joana M.; Srinivasan, Sundar; van Loon, Jacco Th.; Whitney, Barbara; Woods, Paul M.

    2014-12-01

    Observations from the HERschel Inventory of the Agents of Galaxy Evolution (HERITAGE) have been used to identify dusty populations of sources in the Large and Small Magellanic Clouds (LMC and SMC). We conducted the study using the HERITAGE catalogs of point sources available from the Herschel Science Center from both the Photodetector Array Camera and Spectrometer (PACS; 100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE; 250, 350, and 500 μm) cameras. These catalogs are matched to each other to create a Herschel band-merged catalog and then further matched to archival Spitzer IRAC and MIPS catalogs from the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and SAGE-SMC surveys to create single mid- to far-infrared (far-IR) point source catalogs that span the wavelength range from 3.6 to 500 μm. There are 35,322 unique sources in the LMC and 7503 in the SMC. To be bright in the FIR, a source must be very dusty, and so the sources in the HERITAGE catalogs represent the dustiest populations of sources. The brightest HERITAGE sources are dominated by young stellar objects (YSOs), and the dimmest by background galaxies. We identify the sources most likely to be background galaxies by first considering their morphology (distant galaxies are point-like at the resolution of Herschel) and then comparing the flux distribution to that of the Herschel Astrophysical Terahertz Large Area Survey (ATLAS) survey of galaxies. We find a total of 9745 background galaxy candidates in the LMC HERITAGE images and 5111 in the SMC images, in agreement with the number predicted by extrapolating from the ATLAS flux distribution. The majority of the Magellanic Cloud-residing sources are either very young, embedded forming stars or dusty clumps of the interstellar medium. Using the presence of 24 μm emission as a tracer of star formation, we identify 3518 YSO candidates in the LMC and 663 in the SMC. There are far fewer far-IR bright YSOs in the SMC than the LMC

  14. Evolution of the stellar-merger red nova V1309 Scorpii: Spectral energy distribution analysis

    Science.gov (United States)

    Tylenda, R.; Kamiński, T.

    2016-08-01

    Context. One very important object for understanding the nature of red novae is V1309 Sco. Its pre-outburst observations showed that, before its red-nova eruption in 2008, it was a contact binary quickly evolving to the merger of the components. It thus provided us with a direct evidence that the red novae result from stellar mergers. Aims: We will study the evolution of the post-merger remnant of V1309 Sco over time. Methods: We analyse the spectral energy distribution (SED) of the object and its evolution with time. From various optical and infrared surveys and observing programmes carried out with OGLE, HST, VVV, Gemini South, WISE, Spitzer, and Herschel we constructed observed SED in 2010 and 2012. Some limited data are also available for the red-nova progenitor in 2007. We analyse the data with our model of a dusty envelope surrounding a central star. Results: Dust was present in the pre-outburst state of V1309 Sco. Its high temperature (900-1000 K) suggests that this was a freshly formed dust in a presumable mass-loss from the spiralling-in binary. Shortly after its 2008 eruption, V1309 Sco became almost completely embedded in dust. The parameters (temperature, dimensions) of the dusty envelope in 2010 and 2012 evidence that we then observed matter lost by the object during the 2008 outburst. Its mass is at least 10-3M⊙. The object remains quite luminous, although since its maximum brightness in September 2008, it has faded in luminosity by a factor of ~50 (in 2012). Far infrared data from Herschel reveal presence of a cold (~30 K) dust at a distance of a few thousand AU from the object. Conclusions: Similarly to other red novae, V1309 Sco formed a slowly-expanding, dense, and optically-thick dusty envelope during its 2008 outburst. The main remnant is thus hidden for us. Far infrared data suggests that the object passed an episode of intense mass loss in its recent history. This conclusion could be verified by submillimeter interferometric observations.

  15. Inhibitory Effects of Far-Infrared Ray-Emitting Belts on Primary Dysmenorrhea

    Directory of Open Access Journals (Sweden)

    Ben-Yi Liau

    2012-01-01

    Full Text Available This study investigated the therapeutic effect of the far-infrared ray-emitting belt (FIRB in the management of primary dysmenorrhea in female patients. Forty adolescent females with primary dysmenorrhea were enrolled in the study. Quantitative measurements were taken during the menstruation. Several parameters were measured and compared, including temperature, abdominal blood flow, heart rate variability, and pain assessment. Statistical analysis shows that treatment with FIRB had significant efficiency in increasing regional surface temperature and abdominal blood flow, widening standard deviation of normal-to-normal RR intervals, and reducing VRS and NRS pain scores. The application of an FIRB appears to alleviate dysmenorrhea.

  16. Far-infrared phonon-polariton dispersion probed by terahertz time-domain spectroscopy

    Science.gov (United States)

    Kojima, Seiji; Tsumura, Naoki; Takeda, Mitsuo Wada; Nishizawa, Seizi

    2003-01-01

    We report observations of the intensity and phase transmission spectra related to phonon-polariton propagation using coherent far-infrared radiation for a high-quality ferroelectric bismuth titanate crystal plate. In order to determine the polariton-dispersion relation, the phase delay was determined minutely as a function of the THz radiation frequency in the region between 3 and 100 cm-1. The anisotropy of polariton dispersion relation was also successfully determined on the c plate simply by switching the polarization direction of an incident beam from E∥a to E∥b. The observed polariton dispersion relations are consistently reproduced by the calculation using Kurosawa’s formula.

  17. Far-infrared dust properties in the Galaxy and the Magellanic Clouds

    OpenAIRE

    Hirashita, Hiroyuki; Hibi, Yasunori; SHIBAI, Hiroshi

    2007-01-01

    A recent data analysis of the far-infrared (FIR) map of the Galaxy and the Magellanic Clouds has shown that there is a tight correlation between two FIR colours: the 60 um-100 um and 100 um-140 um colours. This FIR colour relation called ``main correlation'' can be interpreted as indicative of a sequence of various interstellar radiation fields with a common FIR optical property of grains. In this paper, we constrain the FIR optical properties of grains by comparing the calculated FIR colours...

  18. Far-infrared laser scattering in the ACT-I toroidal device

    Energy Technology Data Exchange (ETDEWEB)

    Goree, J.; Mansfield, D.K.; Ono, M.; Wong, K.L.

    1984-12-01

    A far-infrared laser scattering diagnostic has been built for the ACT-I toroidal device. The optical system uses a passively stabilized 447-..mu..m CH/sub 3/I laser. A polyethylene etalon is the beam splitter. The vacuum windows are plastic (TPX), which we found has the vacuum property Q 6.5 x 10/sup -9/ torr-liter/sec/cm/sup 2/. Using paraboloidal and ellipsoidal mirrors for detection optics improves the signal strength and allows a better rf enclosure design for the detector. The diagnostic was tested by scattering from an ion Bernstein wave, a technique which can be used for ion temperature diagnostics.

  19. Far infrared-assisted encapsulation of filter paper strips in poly(methyl methacrylate) for proteolysis.

    Science.gov (United States)

    Chen, Qiwen; Bao, Huimin; Zhang, Luyan; Chen, Gang

    2016-02-01

    Filter paper strips were enclosed between two poly(methyl methacrylate) plates to fabricate paper-packed channel microchips under pressure in the presence of far infrared irradiation. After the enclosed paper strip was oxidized by periodate, trypsin was covalently immobilized in them to fabricate microfluidic proteolysis bioreactor. The feasibility and performance of the unique bioreactor were demonstrated by digesting BSA and lysozyme. The results were comparable to those of conventional in-solution proteolysis while the digestion time was significantly reduced to ∼18 s. The suitability of the microfluidic paper-based bioreactors to complex proteins was demonstrated by digesting human serum.

  20. Rotational frequencies of transition metal hydrides for astrophysical searches in the far-infrared

    Science.gov (United States)

    Brown, John M.; Beaton, Stuart P.; Evenson, Kenneth M.

    1993-01-01

    Accurate frequencies for the lowest rotational transitions of five transition metal hydrides (CrH, FeH, CoH, NiH, and CuH) in their ground electronic states are reported to help the identification of these species in astrophysical sources from their far-infrared spectra. Accurate frequencies are determined in two ways: for CuH, by calculation from rotational constants determined from higher J transitions with an accuracy of 190 kHz; for the other species, by extrapolation to zero magnetic field from laser magnetic resonance spectra with an accuracy of 0.7 MHz.

  1. Characterizing the Youngest Herschel-detected Protostars. II. Molecular Outflows from the Millimeter and the Far-infrared

    Science.gov (United States)

    Tobin, John J.; Stutz, Amelia M.; Manoj, P.; Megeath, S. Thomas; Karska, Agata; Nagy, Zsofia; Wyrowski, Friedrich; Fischer, William J.; Watson, Dan M.; Stanke, Thomas

    2016-11-01

    We present Combined Array for Research in Millimeter-wave Astronomy (CARMA) CO (J=1\\to 0) observations and Herschel PACS spectroscopy, characterizing the outflow properties toward extremely young and deeply embedded protostars in the Orion molecular clouds. The sample comprises a subset of the Orion protostars known as the PACS Bright Red Sources (PBRS; Stutz et al.). We observed 14 PBRS with CARMA and 8 of these 14 with Herschel, acquiring full spectral scans from 55 to 200 μm. Outflows are detected in CO (J=1\\to 0) from 8 of 14 PBRS, with two additional tentative detections; outflows are also detected from the outbursting protostar HOPS 223 (V2775 Ori) and the Class I protostar HOPS 68. The outflows have a range of morphologies; some are spatially compact, 13) CO lines and/or H2O lines from 5 of 8 PBRS and only for those with detected CO outflows. The far-infrared CO rotation temperatures of the detected PBRS are marginally colder (˜230 K) than those observed for most protostars (˜300 K), and only one of these five PBRS has detected [O i] 63 μm emission. The high envelope densities could be obscuring some [O i] emission and cause a ˜20 K reduction to the CO rotation temperatures. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  2. Far-infrared to millimeter astrophysical dust emission. II. Comparison of the two-level systems (TLS) model with astronomical data

    Science.gov (United States)

    Paradis, D.; Bernard, J.-P.; Mény, C.; Gromov, V.

    2011-10-01

    Aims: In a previous paper we proposed a new model for the emission by amorphous astronomical dust grains, based on solid-state physics. The model uses a description of the disordered charge distribution (DCD) combined with the presence of two-level systems (TLS) defects in the amorphous solid composing the grains. The goal of this paper is to compare this new model to astronomical observations of different Galactic environments in the far-infrared/submillimeter, in order to derive a set of canonical model parameters to be used as a Galactic reference to be compared to in future Galactic and extragalactic studies. Methods: We compare the TLS model with existing astronomical data. We consider the average emission spectrum at high latitudes in our Galaxy as measured with FIRAS and WMAP, as well as the emission from Galactic compact sources observed with the Archeops balloon experiment, for which an inverse relationship between the dust temperature and the emissivity spectral index has been shown. Results: We show that, unlike models previously proposed that often invoke two dust components at different temperatures, the TLS model successfully reproduces both the shape of the Galactic spectral energy distribution and its evolution with temperature as observed in the Archeops data. The best TLS model parameters indicate a charge coherence length of ≃13 nm and other model parameters in broad agreement with expectations from laboratory studies of dust analogs. We conclude that the millimeter excess emission, which is often attributed to the presence of very cold dust in the diffuse ISM, is very likely caused solely by TLS emission in disordered amorphous dust grains. We discuss the implications of the new model, in terms of mass determinations from millimeter continuum observations and the expected variations in the emissivity spectral index with wavelength and dust temperature. The implications for analyzing the Herschel and Planck satellite data are discussed. Table 5

  3. Spectral unfolding of fast neutron energy distributions

    Science.gov (United States)

    Mosby, Michelle; Jackman, Kevin; Engle, Jonathan

    2015-10-01

    The characterization of the energy distribution of a neutron flux is difficult in experiments with constrained geometry where techniques such as time of flight cannot be used to resolve the distribution. The measurement of neutron fluxes in reactors, which often present similar challenges, has been accomplished using radioactivation foils as an indirect probe. Spectral unfolding codes use statistical methods to adjust MCNP predictions of neutron energy distributions using quantified radioactive residuals produced in these foils. We have applied a modification of this established neutron flux characterization technique to experimentally characterize the neutron flux in the critical assemblies at the Nevada National Security Site (NNSS) and the spallation neutron flux at the Isotope Production Facility (IPF) at Los Alamos National Laboratory (LANL). Results of the unfolding procedure are presented and compared with a priori MCNP predictions, and the implications for measurements using the neutron fluxes at these facilities are discussed.

  4. Herschel-ATLAS: far-infrared properties of radio-selected galaxies

    CERN Document Server

    Hardcastle, M J; Jarvis, M J; Bonfield, D G; Dunne, L; Rawlings, S; Stevens, J A; Christopher, N M; Heywood, I; Mauch, T; Rigopoulou, D; Verma, A; Baldry, I K; Bamford, S P; Buttiglione, S; Cava, A; Clements, D L; Cooray, A; Croom, S M; Dariush, A; De Zotti, G; Eales, S; Fritz, J; Hill, D T; Hughes, D; Hopwood, R; Ibar, E; Ivison, R J; Jones, D H; Loveday, J; Maddox, S J; Michalowski, M J; Negrello, M; Norberg, P; Pohlen, M; Prescott, M; Rigby, E E; Robotham, A S G; Rodighiero, G; Scott, D; Sharp, R; Smith, D J B; Temi, P; van Kampen, E

    2010-01-01

    We use the Herschel-ATLAS science demonstration data to investigate the star-formation properties of radio-selected galaxies in the GAMA-9h field as a function of radio luminosity and redshift. Radio selection at the lowest radio luminosities, as expected, selects mostly starburst galaxies. At higher radio luminosities, where the population is dominated by AGN, we find that some individual objects are associated with high far-infrared luminosities. However, the far-infrared properties of the radio-loud population are statistically indistinguishable from those of a comparison population of radio-quiet galaxies matched in redshift and K-band absolute magnitude. There is thus no evidence that the host galaxies of these largely low-luminosity (Fanaroff-Riley class I), and presumably low-excitation, AGN, as a population, have particularly unusual star-formation histories. Models in which the AGN activity in higher-luminosity, high-excitation radio galaxies is triggered by major mergers would predict a luminosity-d...

  5. Effects of Somatothermal Far-Infrared Ray on Primary Dysmenorrhea: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Yu-Min Ke

    2012-01-01

    Full Text Available The purpose of this study was to assess the beneficial effects of using a far-infrared (FIR belt on the management of patients with primary dysmenorrhea. This is the first study to determine the efficacy of somatothermal FIR using a parallel-arm randomized sham-controlled and double-blinded design with objective physical evidence and psychometric self-reports. Fifty-one Taiwanese women with primary dysmenorrhea were enrolled in the study. Results indicate that there was an increased abdominal temperature of 0.6°C and a 3.27% increase in abdominal blood flow in the FIR group (wearing FIR belt compared to those in the control group (wearing sham belt. Verbal rating scale and numeric rating scale scores in the FIR group were both lower than those in the control group. Compared to the blank group (wearing no belt, the average dysmenorrhea pain duration of the FIR group was significantly reduced from 2.5 to 1.8 days, but there was no significant difference in the control group. These results demonstrate that the use of a belt made of far-infrared ceramic materials can reduce primary dysmenorrhea.

  6. The Far-Infrared-Radio Correlation in MS0451-03

    CERN Document Server

    Randriamampandry, S M; Cress, C M; Hess, K M; Vaccari, M; Wilcots, E M; Bershady, M A; Wirth, G D

    2014-01-01

    We present a multi-wavelength analysis of star-forming galaxies in the massive cluster MS0451.6-0305 at z $\\sim$ 0.54 to shed new light on the evolution of the far-infrared-radio relationship in distant rich clusters. We have derived total infrared luminosities for a spectroscopically confirmed sample of cluster and field galaxies through an empirical relation based on $Spitzer$ MIPS 24 $\\mu$m photometry. The radio flux densities were measured from deep Very Large Array 1.4 GHz radio continuum observations. We find the ratio of far-infrared to radio luminosity for galaxies in an intermediate redshift cluster to be $q_{\\rm FIR}$ = 1.80$\\pm$0.15 with a dispersion of 0.53. Due to the large intrinsic dispersion, we do not find any observable change in this value with either redshift or environment. However, a higher percentage of galaxies in this cluster show an excess in their radio fluxes when compared to low redshift clusters ($27^{+23}_{-13}\\%$ to $11\\%$), suggestive of a cluster enhancement of radio-excess s...

  7. H-ATLAS: The Far-Infrared properties of galaxies in and around the Coma Cluster

    CERN Document Server

    Fuller, C; Smith, M W L; Valiante, E; Eales, S; Bourne, N; Dunne, L; Dye, S; Furlanetto, C; Ibar, E; Ivison, R; Maddox, S; Sansom, A; Michalowski, M J; Davis, T

    2016-01-01

    We describe a far infrared survey of the Coma cluster and the galaxy filament it resides within. Our survey covers an area of $\\sim$150 deg$^2$ observed by $Herschel$ H-ATLAS in five bands at 100, 160, 250, 350 and 500$\\mu$m. The SDSS spectroscopic survey ($m_{r} \\le 17.8)$ is used to define an area (within the Virial radius) and redshift selected ($4268 < v < 9700$ km s$^{-1}$) sample of 744 Coma cluster galaxies - the Coma Cluster Catalogue (CCC). For comparison we also define a sample of 951 galaxies in the connecting filament - the Coma Filament Catalogue (CFC). The optical positions and parameters are used to define appropriate apertures to measure each galaxy's far infrared emission. We have detected 99 of 744 (13\\%) and 422 of 951 (44\\%) of the cluster and filament galaxies in the SPIRE 250$\\mu$m band. We consider the relative detection rates of galaxies of different morphological types finding that it is only the S0/Sa population that shows clear differences between the cluster and filament. We ...

  8. A sensitivity study for far infrared balloon-borne limb emission sounding of stratospheric trace gases

    Directory of Open Access Journals (Sweden)

    J. Xu

    2013-05-01

    Full Text Available This paper presents a sensitivity study performed for trace gases retrieval from synthetic observations by TELIS (TErahertz and submillimeter LImb Sounder which is a stratospheric balloon-borne cryogenic heterodyne spectrometer. Issues pertaining to hydroxyl radical (OH retrieval from the far infrared measurements by the 1.8 THz channel are addressed. The study is conducted by a retrieval code PILS (Profile Inversion for Limb Sounding developed to solve the nonlinear inverse problems arising in the analysis of infrared/microwave limb sounding measurements. PILS combines a line-by-line forward model with automatic differentiation for computing Jacobians and employs regularized nonlinear least squares inversion. We examine the application of direct and iterative regularization methods and evaluate the performance of single- and multi-profile retrievals. Sensitivities to expected errors in calibration procedure, instrumental knowledge and atmospheric profiles have been analyzed. Nonlinearity effect, inaccurate sideband ratio, and pointing error turned out to be the dominant error sources. Furthermore, the capability of multi-channel simultaneous retrieval from the far infrared and submillimeter data has been investigated. The errors and averaging kernels infer that the quality of the obtained hydrogen chloride (HCl can be improved by significantly better exploitation of information from the observations.

  9. The far-infrared emitting region in local galaxies and QSOs: Size and scaling relations

    CERN Document Server

    Lutz, D; Contursi, A; Schreiber, N M Förster; Genzel, R; Graciá-Carpio, J; Herrera-Camus, R; Netzer, H; Sturm, E; Tacconi, L J; Tadaki, K; Veilleux, S

    2015-01-01

    We use Herschel 70 to 160um images to study the size of the far-infrared emitting region in 400 local galaxies and QSO hosts. The sample includes normal `main sequence' star forming galaxies, as well as infrared luminous galaxies and Palomar-Green QSOs, with different level and structure of star formation. Assuming gaussian spatial distribution of the far-infrared emission, the excellent stability of the Herschel point spread function allows us to measure sizes well below the PSF width, by subtracting widths in quadrature. We derive scalings of FIR size and surface brightness of local galaxies with FIR luminosity, with distance from the star forming `main sequence', and with FIR color. Luminosities LFIR~10^11Lsun can be reached with a variety of structures spanning 2 dex in size. Ultraluminous LFIR>~10^12Lsun galaxies far above the main sequence inevitably have small Re,70~0.5kpc FIR emitting regions with large surface brightness, and can be close to optically thick in the FIR on average over these regions. C...

  10. Hi-fidelity multi-scale local processing for visually optimized far-infrared Herschel images

    Science.gov (United States)

    Li Causi, G.; Schisano, E.; Liu, S. J.; Molinari, S.; Di Giorgio, A.

    2016-07-01

    In the context of the "Hi-Gal" multi-band full-plane mapping program for the Galactic Plane, as imaged by the Herschel far-infrared satellite, we have developed a semi-automatic tool which produces high definition, high quality color maps optimized for visual perception of extended features, like bubbles and filaments, against the high background variations. We project the map tiles of three selected bands onto a 3-channel panorama, which spans the central 130 degrees of galactic longitude times 2.8 degrees of galactic latitude, at the pixel scale of 3.2", in cartesian galactic coordinates. Then we process this image piecewise, applying a custom multi-scale local stretching algorithm, enforced by a local multi-scale color balance. Finally, we apply an edge-preserving contrast enhancement to perform an artifact-free details sharpening. Thanks to this tool, we have thus produced a stunning giga-pixel color image of the far-infrared Galactic Plane that we made publicly available with the recent release of the Hi-Gal mosaics and compact source catalog.

  11. Cosmological Constant or Intergalactic Dust? Constraints from the Cosmic Far Infrared Background

    CERN Document Server

    Aguirre, A N; Aguirre, Anthony; Haiman, Zoltan

    1999-01-01

    Recent observations of Type Ia SNe at redshifts 0 ~ 0.1 micron dust grains with a mass density of Omega_dust ~ (few) * 10^{-5} in the intergalactic (IG) medium. The same dust that dims the SNe absorbs the cosmic UV/optical background radiation around ~ 1 micron, and re-emits it at far infrared (FIR) wavelengths. Here we compare the FIR emission from IG dust with observations of the cosmic microwave (CMB) and cosmic far infrared backgrounds (FIRB) by the DIRBE/FIRAS instruments. We find that the emission would not lead to measurable distortion to the CMB, but would represent a substantial fraction (> 50 %) of the measured value of the FIRB in the 300-1000 micron range. This contribution would be consistent with the present unresolved fraction of the observed FIRB in an open universe. However, we find that IG dust probably could not reconcile the standard Omega=1 CDM model with the SN observations, even if the necessary quantity of dust existed. Future observations able to resolve the FIRB to a flux limit of ~ ...

  12. Interpreting the cosmic far-infrared background anisotropies using a gas regulator model

    CERN Document Server

    Wu, Hao-Yi; Teyssier, Romain

    2016-01-01

    Cosmic far-infrared background (CFIRB) is a powerful probe of the history of star formation rate and the connection between baryons and dark matter. In this work, we explore to which extent the CFIRB anisotropies can be reproduced by a simple physical framework for galaxy evolution, the gas regulator (bathtub) model. The model is based on continuity equations for gas, stars, and metals, taking into account cosmic gas accretion, star formation, and gas ejection. Our model not only provides a good fit to the CFIRB power spectra measured by Planck, but also agrees well with the correlation between CFIRB and gravitational lensing, far-infrared galaxy number counts, and bolometric infrared luminosity functions. The strong clustering of CFIRB indicates a large galaxy bias, which corresponds to haloes of mass 10^12.5 Msun at z=2; thus, CFIRB favors strong infrared emission in massive haloes, which is higher than the expectation from the star formation rate. We provide constraints and fitting functions for the cosmic...

  13. Far-infrared and sub-millimetre imaging of HD~76582's circumstellar disk

    CERN Document Server

    Marshall, J P; Holland, W S; Matthews, B C; Greaves, J S; Zuckerman, B

    2016-01-01

    Debris disks, the tenuous rocky and icy remnants of planet formation, are believed to be evidence for planetary systems around other stars. The JCMT/SCUBA-2 debris disk legacy survey 'SCUBA-2 Observations of Nearby Stars' (SONS) observed 100 nearby stars, amongst them HD~76582, for evidence of such material. Here we present imaging observations by JCMT/SCUBA-2 and \\textit{Herschel}/PACS at sub-millimetre and far-infrared wavelengths, respectively. We simultaneously model the ensemble of photometric and imaging data, spanning optical to sub-millimetre wavelengths, in a self-consistent manner. At far-infrared wavelengths, we find extended emission from the circumstellar disk providing a strong constraint on the dust spatial location in the outer system, although the angular resolution is too poor to constrain the interior of the system. In the sub-millimetre, photometry at 450 and 850~$\\mu$m reveal a steep fall-off that we interpret as a disk dominated by moderately-sized dust grains ($a_{\\rm min}~=~36~\\mu$m), ...

  14. Radio Continuum and Far-infrared Emission from the Galaxies in the Eridanus Group

    Indian Academy of Sciences (India)

    A. Omar; K. S. Dwarakanath

    2005-03-01

    The Eridanus galaxies follow the well-known radio–FIR correlation. The majority (70%) of these galaxies have their star formation rates below that of the Milky Way. The galaxies that have a significant excess of radio emission are identified as low luminosity AGNs based on their radio morphologies obtained from the GMRT observations. There are no powerful AGNs (20cm > 1023W Hz-1) in the group. The two most far-infrared and radio luminous galaxies in the group have optical and HI morphologies suggestive of recent tidal interactions. The Eridanus group also has two far-infrared luminous but radio-deficient galaxies. It is believed that these galaxies are observed within a few Myr of the onset of an intense star formation episode after being quiescent for at least a 100 Myr. The upper end of the radio luminosity distribution of the Eridanus galaxies (20cm ∼ 1022W Hz-1) is consistent with that of the field galaxies, other groups, and late-type galaxies in nearby clusters.

  15. Far-infrared emission from intergalactic medium in Stephan's Quintet revealed by AKARI

    CERN Document Server

    Suzuki, Toyoaki; Onaka, Takashi; Kitayama, Tetsu

    2011-01-01

    The Stephan's Quintet (SQ, HCG92) was observed with the Far-Infrared Surveyor (FIS) aboard AKARI in four far-infrared (IR) bands at 65, 90, 140, and 160 um. The AKARI four-band images of the SQ show far-IR emission in the intergalactic medium (IGM) of the SQ. In particular, the 160 um band image shows single peak emission in addition to the structure extending in the North-South direction along the shock ridge as seen in the 140 um band, H2 emission and X-ray emission. Whereas most of the far-IR emission in the shocked region comes from the cold dust component, shock-powered [CII]158um emission can significantly contribute to the emission in the 160 um band that shows a single peak at the shocked region. In the shocked region, the observed gas-to-dust mass ratio is in agreement with the Galactic one. The color temperature of the cold dust component (~20 K) is lower than that in surrounding galaxies (~30 K). We discuss a possible origin of the intergalactic dust emission.

  16. Panchromatic spectral energy distributions of Herschel sources

    CERN Document Server

    Berta, S; Santini, P; Wuyts, S; Rosario, D; Brisbin, D; Cooray, A; Franceschini, A; Gruppioni, C; Hatziminaoglou, E; Hwang, H S; Floc'h, E Le; Magnelli, B; Nordon, R; Oliver, S; Page, M J; Popesso, P; Pozzetti, L; Pozzi, F; Riguccini, L; Rodighiero, G; Roseboom, I; Scott, Douglas; Symeonidis, M; Valtchanov, I; Viero, M; Wang, L

    2013-01-01

    (abridged) Far-infrared Herschel photometry from the PEP and HerMES programs is combined with ancillary datasets in the GOODS-N, GOODS-S, and COSMOS fields. Based on this rich dataset, we reproduce the restframe UV to FIR ten-colors distribution of galaxies using a superposition of multi-variate Gaussian modes. The median SED of each mode is then fitted with a modified version of the MAGPHYS code that combines stellar light, emission from dust heated by stars and a possible warm dust contribution heated by an AGN. The defined Gaussian grouping is also used to identify rare sources. The zoology of outliers includes Herschel-detected ellipticals, very blue z~1 Ly-break galaxies, quiescent spirals, and torus-dominated AGN with star formation. Out of these groups and outliers, a new template library is assembled, consisting of 32 SEDs describing the intrinsic scatter in the restframe UV-to-submm colors of infrared galaxies. This library is tested against L(IR) estimates with and without Herschel data included, an...

  17. Far-infrared/submillimetre properties of pre-stellar cores L1521E, L1521F and L1689B as revealed by the Herschel SPIRE instrument - I. Central positions

    Science.gov (United States)

    Makiwa, G.; Naylor, D. A.; van der Wiel, M. H. D.; Ward-Thompson, D.; Kirk, J. M.; Eyres, S.; Abergel, A.; Köhler, M.

    2016-05-01

    Dust grains play a key role in the physics of star-forming regions, even though they constitute only ˜1 per cent of the mass of the interstellar medium. The derivation of accurate dust parameters such as temperature (Td), emissivity spectral index (β) and column density requires broad-band continuum observations at far-infrared wavelengths. We present Herschel-Spectral and Photometric Imaging Receiver Array (SPIRE) Fourier Transform Spectrometer (FTS) measurements of three starless cores: L1521E, L1521F and L1689B, covering wavelengths between 194 and 671 μm. This paper is the first to use our recently updated SPIRE-FTS intensity calibration, yielding a direct match with SPIRE photometer measurements of extended sources. In addition, we carefully assess the validity of calibration schemes depending on-source extent and on the strength of background emission. The broad-band far-infrared spectra for all three sources peak near 250 μm. Our observations therefore provide much tighter constraints on the spectral energy distribution (SED) shape than measurements that do not probe the SED peak. The spectra are fitted using modified blackbody functions, allowing both Td and β to vary as free parameters. This yields Td of 9.8±0.2, 15.6±0.5 and 10.9±0.2 K and corresponding β of 2.6∓0.9, 0.8∓0.1 and 2.4∓0.8 for L1521E, L1521F and L1689B, respectively. The derived core masses are 1.0±0.1, 0.10±0.01 and 0.49±0.05 M⊙, respectively. The core mass/Jeans mass ratios for L1521E and L1689B exceed unity indicating that they are unstable to gravitational collapse, and thus pre-stellar cores. By comparison, the elevated temperature and gravitational stability of L1521F support previous arguments that this source is more evolved and likely a protostar.

  18. The Spectral Energy Distributions of Fermi Blazars

    Science.gov (United States)

    Fan, J. H.; Yang, J. H.; Liu, Y.; Luo, G. Y.; Lin, C.; Yuan, Y. H.; Xiao, H. B.; Zhou, A. Y.; Hua, T. X.; Pei, Z. Y.

    2016-10-01

    In this paper, multiwavelength data are compiled for a sample of 1425 Fermi blazars to calculate their spectral energy distributions (SEDs). A parabolic function, {{log}}{(ν {F}ν )={P}1({{log}}ν -{P}2)}2+{P}3, is used for SED fitting. Synchrotron peak frequency ({log}{ν }{{p}}), spectral curvature (P1), peak flux ({ν }{{p}}{F}{ν {{p}}}), and integrated flux (ν {F}ν ) are successfully obtained for 1392 blazars (461 flat-spectrum radio quasars [FSRQs], 620 BL Lacs [BLs], and 311 blazars of uncertain type [BCUs]; 999 sources have known redshifts). Monochromatic luminosity at radio 1.4 GHz, optical R band, X-ray at 1 keV and γ-ray at 1 GeV, peak luminosity, integrated luminosity, and effective spectral indices of radio to optical ({α }{{RO}}) and optical to X-ray ({α }{{OX}}) are calculated. The “Bayesian classification” is employed to log {ν }{{p}} in the rest frame for 999 blazars with available redshift, and the results show that three components are enough to fit the log {ν }{{p}} distribution; there is no ultra-high peaked subclass. Based on the three components, the subclasses of blazars using the acronyms of Abdo et al. are classified, and some mutual correlations are also studied. Conclusions are finally drawn as follows: (1) SEDs are successfully obtained for 1392 blazars. The fitted peak frequencies are compared with common sources from available samples. (2) Blazars are classified as low synchrotron peak sources if log {ν }{{p}}({Hz})≤slant 14.0, intermediate synchrotron peak sources if 14.0\\lt {log} {ν }{{p}}({Hz})≤slant 15.3, and high synchrotron peak sources if {log} {ν }{{p}}({Hz})\\gt 15.3. (3) Gamma-ray emissions are strongly correlated with radio emissions. Gamma-ray luminosity is also correlated with synchrotron peak luminosity and integrated luminosity. (4) There is an anticorrelation between peak frequency and peak luminosity within the whole blazar sample. However, there is a marginally positive correlation for high

  19. Far infrared (terahertz) spectroscopy of a series of polycyclic aromatic hydrocarbons and application to structure interpretation of asphaltenes and related compounds.

    Science.gov (United States)

    Cataldo, Franco; Angelini, Giancarlo; García-Hernández, D Aníbal; Manchado, Arturo

    2013-07-01

    A series of 33 different polycyclic aromatic hydrocarbons (PAHs) were studied by far infrared spectroscopy (terahertz spectroscopy) in the spectral range comprised between 600 and 50 cm(-1). In addition to common PAHs like naphthalene, anthracene, phenanthrene, fluoranthene, picene, pyrene, benzo[α]pyrene, and perylene, also quite unusual PAHs were studied like tetracene, pentacene, acenaphtene, acenaphtylene, triphenylene, and decacyclene. A series of alkylated naphthalenes and anthracenes were studied as well as methypyrene. Partially or totally hydrogenated PAHs were also object of the present investigation, ranging from tetrahydronaphthalene (tetralin) to decahydronaphthalene (decalin), 9,10-dihydroanthracene, 9,10-dihydrophenanthrene, hexahydropyrene, and dodecahydrotriphenylene. Finally, the large and quite rare PAHs coronene, quaterrylene, hexabenzocoronene, and dicoronylene were studied by far infrared spectroscopy. The resulting reference spectra were used in the interpretation of the chemical structure of asphaltenes (as extracted from a heavy petroleum fraction and from bitumen), the chemical structures of other petroleum fractions known as DAE (distillate aromatic extract) and RAE (residual aromatic extract), and a possible interpretation of components of the chemical structure of anthracite coal. Asphaltenes, heavy petroleum fractions, and coal were proposed as model compounds for the interpretation of the emission spectra of certain proto-planetary nebulae (PPNe) with a good matching in the mid infrared between the band pattern of the PPNe emission spectra and the spectra of these oil fractions or coal. Although this study was finalized in an astrochemical context, it may find application also in the petroleum and coal chemistry.

  20. Far infrared (terahertz) spectroscopy of a series of polycyclic aromatic hydrocarbons and application to structure interpretation of asphaltenes and related compounds

    Science.gov (United States)

    Cataldo, Franco; Angelini, Giancarlo; García-Hernández, D. A.; Manchado, Arturo

    2013-07-01

    A series of 33 different polycyclic aromatic hydrocarbons (PAHs) were studied by far infrared spectroscopy (terahertz spectroscopy) in the spectral range comprised between 600 and 50 cm-1. In addition to common PAHs like naphthalene, anthracene, phenanthrene, fluoranthene, picene, pyrene, benzo[α]pyrene, and perylene, also quite unusual PAHs were studied like tetracene, pentacene, acenaphtene, acenaphtylene, triphenylene, and decacyclene. A series of alkylated naphthalenes and anthracenes were studied as well as methypyrene. Partially or totally hydrogenated PAHs were also object of the present investigation, ranging from tetrahydronaphthalene (tetralin) to decahydronaphthalene (decalin), 9,10-dihydroanthracene, 9,10-dihydrophenanthrene, hexahydropyrene, and dodecahydrotriphenylene. Finally, the large and quite rare PAHs coronene, quaterrylene, hexabenzocoronene, and dicoronylene were studied by far infrared spectroscopy. The resulting reference spectra were used in the interpretation of the chemical structure of asphaltenes (as extracted from a heavy petroleum fraction and from bitumen), the chemical structures of other petroleum fractions known as DAE (distillate aromatic extract) and RAE (residual aromatic extract), and a possible interpretation of components of the chemical structure of anthracite coal. Asphaltenes, heavy petroleum fractions, and coal were proposed as model compounds for the interpretation of the emission spectra of certain proto-planetary nebulae (PPNe) with a good matching in the mid infrared between the band pattern of the PPNe emission spectra and the spectra of these oil fractions or coal. Although this study was finalized in an astrochemical context, it may find application also in the petroleum and coal chemistry.

  1. Far-infrared synchrotron radiation spectroscopy of solids in normal and extreme conditions

    Science.gov (United States)

    Piccinini, M.; Cestelli Guidi, M.; Marcelli, A.; Calvani, P.; Burattini, E.; Nucara, A.; Postorino, P.; Sacchetti, A.; Arcangeletti, E.; Sheregii, E.; Polit, J.; Kisiel, A.

    2005-01-01

    New opportunities in solid-state physics are offered by SINBAD (Synchrotron INfrared Beamline At DAFNE), the infrared beamline operational at DANE, the storage ring of the Laboratori Nazionali di Frascati of the INFN. During 2003 several experiments, including those supported by the European TARI program, have been successfully performed at SINBAD. In this work we present the preliminary results of high resolution far infrared reflectivity data collected in different ZnxCdyHg(1-x-y)Te quaternary alloys as a function of temperature. The first far-IR investigation of Colossal Magnetoresistance manganites at high pressures, using a diamond anvil cell is also presented. Indeed, FT-IR spectroscopy is a powerful tool for the investigation of insulating-to-metal transitions and charge ordering phenomena that may occur in transition metal oxides.

  2. Far-infrared Michelson interferometer for tokamak electron density measurements using computer-generated reference fringes

    Energy Technology Data Exchange (ETDEWEB)

    Krug, P.A.; Stimson, P.A.; Falconer, I.S.

    1986-11-01

    A simple far-infrared interferometer which uses the 394 ..mu..m laser line from optically-pumped formic acid vapour to measure tokamak electron density is described. This interferometer is unusual in requiring only one detector and a single probing beam since reference fringes during the plasma shot are obtained by computer interpolation between the fringes observed immediately before and after the shot. Electron density has been measured with a phase resolution corresponding to + - 1/20 wavelength fringe shift, which is equivalent to a central density resolution of + - 0.1 x 10/sup 19/ m/sup -3/ for an assumed parabolic density distribution in a plasma of diameter of 0.2 m, and with a time resolution of 0.2 ms.

  3. Symmetric Absorber-Coupled Far-Infrared Microwave Kinetic Inductance Detector

    Science.gov (United States)

    U-yen, Kongpop (Inventor); Wollack, Edward J. (Inventor); Brown, Ari D. (Inventor); Stevenson, Thomas R. (Inventor); Patel, Amil A. (Inventor)

    2016-01-01

    The present invention relates to a symmetric absorber-coupled far-infrared microwave kinetic inductance detector including: a membrane having an absorber disposed thereon in a symmetric cross bar pattern; and a microstrip including a plurality of conductor microstrip lines disposed along all edges of the membrane, and separated from a ground plane by the membrane. The conducting microstrip lines are made from niobium, and the pattern is made from a superconducting material with a transition temperature below niobium, including one of aluminum, titanium nitride, or molybdenum nitride. The pattern is disposed on both a top and a bottom of the membrane, and creates a parallel-plate coupled transmission line on the membrane that acts as a half-wavelength resonator at readout frequencies. The parallel-plate coupled transmission line and the conductor microstrip lines form a stepped impedance resonator. The pattern provides identical power absorption for both horizontal and vertical polarization signals.

  4. Drunk identification using far infrared imagery based on DCT features in DWT domain

    Science.gov (United States)

    Xie, Zhihua; Jiang, Peng; Xiong, Ying; Li, Ke

    2016-10-01

    Drunk driving problem is a serious threat to traffic safety. Automatic drunk driver identification is vital to improve the traffic safety. This paper copes with automatic drunk driver detection using far infrared thermal images by the holistic features. To improve the robustness of drunk driver detection, instead of traditional local pixels, a holistic feature extraction method is proposed to attain compact and discriminative features for infrared face drunk identification. Discrete cosine transform (DCT) in discrete wavelet transform (DWT) domain is used to extract the useful features in infrared face images for its high speed. Then, the first six DCT coefficients are retained for drunk classification by means of "Z" scanning. Finally, SVM is applied to classify the drunk person. Experimental results illustrate that the accuracy rate of proposed infrared face drunk identification can reach 98.5% with high computation efficiency, which can be applied in real drunk driver detection system.

  5. A Demonstration of TIA Using FD-SOI CMOS OPAMP for Far-Infrared Astronomy

    Science.gov (United States)

    Nagase, Koichi; Wada, Takehiko; Ikeda, Hirokazu; Arai, Yasuo; Ohno, Morifumi; Hanaoka, Misaki; Kanada, Hidehiro; Oyabu, Shinki; Hattori, Yasuki; Ukai, Sota; Suzuki, Toyoaki; Watanabe, Kentaroh; Baba, Shunsuke; Kochi, Chihiro; Yamamoto, Keita

    2016-07-01

    We are developing a fully depleted silicon-on-insulator (FD-SOI) CMOS readout integrated circuit (ROIC) operated at temperatures below ˜ 4 K. Its application is planned for the readout circuit of high-impedance far-infrared detectors for astronomical observations. We designed a trans-impedance amplifier (TIA) using a CMOS operational amplifier (OPAMP) with FD-SOI technique. The TIA is optimized to readout signals from a germanium blocked impurity band (Ge BIB) detector which is highly sensitive to wavelengths of up to ˜ 200 \\upmu m. For the first time, we demonstrated the FD-SOI CMOS OPAMP combined with the Ge BIB detector at 4.5 K. The result promises to solve issues faced by conventional cryogenic ROICs.

  6. Detector Response and Beam Line Transmission Measurements with Far-Infrared Radiation

    CERN Document Server

    Grimm, O; Fröhlich, L

    2005-01-01

    Various activities at the TTF linear accelerator at DESY, Hamburg, that drives the VUV-FEL are geared towards measuring the longitudinal charge distribution of electron bunches with coherent far-infrared radiation. Examples are beam lines transporting synchrotron or transition radiation to interferometers mounted inside or outside the tunnel, and studies of single-shot grating spectrometers. All such approaches require a good understanding of the radiation generation and transport mechanism and of the detector characteristics to extract useful information on the charge distribution. Simulations and measurements of the expected transverse intensity distribution and polarization of synchrotron radiation emitted at the first bunch compressor of TTF have been performed. The transverse intensity scanning provided for the first time at DESY a visual image of the footprint of terahertz radiation. Detector response measurements have been performed at the FELIX facility, Netherlands, for wavelengths between 100-160 mi...

  7. Accurate frequency of the 119 micron methanol laser from tunable far-infrared absorption spectroscopy

    Science.gov (United States)

    Inguscio, M.; Zink, L. R.; Evenson, K. M.; Jennings, D. A.

    1990-01-01

    High-accuracy absorption spectroscopy of CH3OH in the far infrared is discussed. In addition to 22 transitions in the ground state, the frequency of the (n, tau, J, K), (0, 1, 16, 8) to (0, 2, 15, 7) transition in the nu5 excited vibrational level, which is responsible for the laser emission at 119 microns, was measured. The measured frequency is 2,522,782.57(10) MHz at zero pressure, with a pressure shift of 6.1(32) kHz/Pa (0.805/420/ MHz/torr). An accurate remeasurement of the laser emission frequency has also been performed, and the results are in good agreement.

  8. The Influence of Chain Dynamics on the Far Infrared Spectrum of Liquid Methanol-Water Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Woods, K.N.; /Stanford U., Phys. Dept.; Wiedemann, H.; /SLAC, SSRL

    2005-07-12

    Far-infrared absorption spectroscopy has been used to study the low frequency ({center_dot} 100 cm{sup -1}) intermolecular modes of methanol in mixtures with water. With the aid of a first principles molecular dynamics simulation on an equivalent system, a detailed understanding about the origin of the low frequency IR modes has been established. The total dipole spectrum from the simulation suggests that the bands appearing in the experimental spectra at approximately 55 cm{sup -1} and 70 cm{sup -1} in methanol and methanol-rich mixtures arise from both fluctuations and torsional motions occurring within the methanol hydrogen-bonded chains. The influence of these modes on both the solvation dynamics and the relaxation mechanisms in the liquid are discussed within the context of recent experimental and theoretical results that have emerged from studies focusing on the short time dynamics in the methanol hydrogen bond network.

  9. Multi-channel far-infrared HL-2A interferometer-polarimeter.

    Science.gov (United States)

    Zhou, Y; Deng, Z C; Li, Y G; Yi, J

    2012-10-01

    An HL-2A interferometer is upgraded to a multi-channel interferometer∕polarimeter, which includes four chords for the interferometer and four chords for the polarimeter. The far-infrared lasers (at λ = 432.5 μm and 30 mW power) are used to probe plasmas horizontally in the midplane of HL-2A. A conventional heterodyne technique is used for the interferometer. Two counter-rotating circularly polarized waves are used to measure the Faraday rotation effect. A fast-phase comparator with temporal resolution of 1 μs and phase resolution 0.1° is developed. Further, the distortion of the polarization caused by the beam-splitters and the other optical components is also investigated.

  10. Multi-channel far-infrared HL-2A interferometer-polarimetera)

    Science.gov (United States)

    Zhou, Y.; Deng, Z. C.; Li, Y. G.; Yi, J.

    2012-10-01

    An HL-2A interferometer is upgraded to a multi-channel interferometer/polarimeter, which includes four chords for the interferometer and four chords for the polarimeter. The far-infrared lasers (at λ = 432.5 μm and 30 mW power) are used to probe plasmas horizontally in the midplane of HL-2A. A conventional heterodyne technique is used for the interferometer. Two counter-rotating circularly polarized waves are used to measure the Faraday rotation effect. A fast-phase comparator with temporal resolution of 1 μs and phase resolution 0.1° is developed. Further, the distortion of the polarization caused by the beam-splitters and the other optical components is also investigated.

  11. Temperature-dependent far-infrared properties of Bi_(12) GeO_(20) single crystal

    Institute of Scientific and Technical Information of China (English)

    Muhammad Kamran; Dai Yao-Min; Ma Ji-Yun; Li Bo-Hong; He Shi-Kun; Zhang Wei-Jun; Zheng Xiao-Rui; Qiu Xiang-Gang

    2009-01-01

    Far-infrared reflectivity spectra of bismuth germanium oxide(Bi_(12)GeO_(20))single crystals are measured from room temperature down to 10 K. All the reflectivity spectra are fitted to a complex dielectric function ε(w) in the factorised form. Phonon modes at low frequency are found to develop upon decreasing temperature and gain considerable spectrum weight below 150 K. The temperature dependent static dielectric constants are obtained from the Lyddane-Sachs-Teller relation based on the obtained oscillator parameters. The dielectric constants are found to increase upon decreasing temperature. which is attributed to the charge transfer among the ions in the unit cell with the temperature varying.

  12. Far-Infrared Study of BaTi4O9 Microwave Dielectric Ceramics

    Science.gov (United States)

    Huang, Xianli; Wang, Fuping; Song, Ying

    2006-02-01

    In this work, lattice vibrations in BaTi4O9 ceramic were investigated using far-infrared spectra (FIRS), which were transformed by Kramers-Kronig relations into the real and imaginary parts of permittivity spectra. Curve fitting of reflectance spectra shows that 32 vibration modes were observed, among which transverse vibrations at lower frequencies (stretching and bending vibration modes involving A-site cations and TiO6 octahedra) account for most dielectric loss. An evaluation of dielectric constants and quality factors using an extrapolation method was accomplished. The calculated dielectric constants agree well with the measured ones, while the calculated dielectric losses are about half the measured ones, indicating that noneigen elements such as defects and pores exist and play an important role in BaTi4O9 ceramics. A multimode behavior of vibration modes involving Ba-sites was proposed as the origin of dielectric loss.

  13. A hybrid type undulator for far-infrared FELs at FELI

    Energy Technology Data Exchange (ETDEWEB)

    Zako, A.; Miyauchi, Y.; Koga, A. [Free Electron Laser Research Institute, Inc., Osaka (Japan)] [and others

    1995-12-31

    Two FEL facilities of the FELI are now operating in the wavelength range of 1-20 {mu}m. A 3.2-m hybrid type undulator ({lambda}{sub u}=80mm, N=40) has been designed for far-infrared FELs and will be installed in December. It can cover the wavelength of 20-60 {mu}m by changing K-value from 1 to 2.7 for a 28.0-MeV electron beam. It is composed of ferrite magnetic poles and Sm-Co permanent magnets. Commonly wound coils induce alternating magnetic field in ferrite poles. Combination of the induced field and the permanent magnet field can controls the magnetic field between the undulator gap.

  14. A minimal empirical model for the cosmic far-infrared background anisotropies

    CERN Document Server

    Wu, Hao-Yi

    2016-01-01

    Cosmic far-infrared background (CFIRB) probes unresolved dusty star-forming galaxies across cosmic time and is complementary to ultraviolet/optical probes of galaxy evolution. In this work, we interpret the observed CFIRB anisotropies using an empirical model based on recent galaxy survey results, including stellar mass functions, star-forming main sequence, and dust attenuation. Without introducing new parameters, our model agrees well with the CFIRB anisotropies observed by Planck and the submillimeter number counts observed by Herschel. We find that the commonly used linear relation between infrared luminosity and star-formation rate over-produces the observed CFIRB amplitudes, and lower infrared luminosities from low-mass galaxies are required. Our results indicate that CFIRB not only provides a consistency check for galaxy evolution models but also informs the star-formation rate and dust content for low-mass galaxies.

  15. Tunable far infrared laser spectroscopy of van der Waals bonds: Ar-NH sub 3

    Energy Technology Data Exchange (ETDEWEB)

    Gwo, Dz-Hung (Lawrence Berkeley Lab., CA (USA) California Univ., Berkeley, CA (USA). Dept. of Chemistry)

    1989-11-01

    Hyperfine resolved vibration-rotation-tunneling spectra of Ar--NH{sub 3} and (NH{sub 3}){sub 2}, generated in a planar supersonic jet, have been measured with the Berkeley tunable far infrared laser spectrometer. Among the seven rotationally assigned bands, one band belongs to Ar--NH{sub 3}, and the other six belong to (NH{sub 3}){sub 2}. To facilitate the intermolecular vibrational assignment for Ar--NH{sub 3}, a dynamics study aided by a permutation-inversion group theoretical treatment is performed on the rovibrational levels. The rovibrational quantum number correlation between the free internal rotor limit and the semi-rigid limit is established to provide a basic physical picture of the evolution of intermolecular vibrational component states. An anomalous vibronically allowed unique Q branch vibrational band structure is predicted to exist for a near prolate binary complex containing an inverting subunit. According to the model developed in this work, the observed band of Ar--NH{sub 3} centered at 26.470633(17) cm{sup {minus}1} can correlate only to either the fundamental dimeric stretching band for the A{sub 2} states with the NH{sub 3} inversional quantum number v{sub i} = 1, or the K{sub a} = 0 {l arrow} 0 subband of the lowest internal-rotation-inversion difference band. Although the estimated nuclear quadrupole coupling constant favors a tentative assignment in terms of the first possibility, a definitive assignment will require far infrared data and a dynamical model incorporating a potential surface.

  16. Third harmonic generation of high power far infrared radiation in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Urban, M. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP)

    1996-04-01

    We investigated the third harmonic generation of high power infrared radiation in doped semiconductors with emphasis on the conversion efficiency. The third harmonic generation effect is based on the nonlinear response of the conduction band electrons in the semiconductor with respect to the electric field of the incident electromagnetic wave. Because this work is directed towards a proposed application in fusion plasma diagnostics, the experimental requirements for the radiation source at the fundamental frequency are roughly given as follows: a wavelength of the radiation at the fundamental frequency in the order of 1 mm and an incident power greater than 1 MW. The most important experiments of this work were performed using the high power far infrared laser of the CRPP. With this laser a new laser line was discovered, which fits exactly the source specifications given above: the wavelength is 676 {mu}m and the maximum power is up to 2 MW. Additional experiments were carried out using a 496 {mu}m laser and a 140 GHz (2.1 mm) gyrotron. The main experimental progress with respect to previous work in this field is, in addition to the use of a very high power laser, the possibility of an absolute calibration of the detectors for the far infrared radiation and the availability of a new type of detector with a very fast response. This detector made it possible to measure the power at the fundamental as well as the third harmonic frequency with full temporal resolution of the fluctuations during the laser pulse. Therefore the power dependence of the third harmonic generation efficiency could be measured directly. The materials investigated were InSb as an example of a narrow gap semiconductor and Si as standard material. The main results are: narrow gap semiconductors indeed have a highly nonlinear electronic response, but the narrow band gap leads at the same time to a low power threshold for internal breakdown, which is due to impact ionization. figs., tabs., refs.

  17. Modeling the light-travel-time effect on the far-infrared size of IRC +10216

    Science.gov (United States)

    Wright, Edward L.; Baganoff, Frederick K.

    1995-01-01

    Models of the far-infrared emission from the large circumstellar dust envelope surrounding the carbon star IRC +10216 are used to assess the importance of the light-travel-time effect (LTTE) on the observed size of the source. The central star is a long-period variable with an average period of 644 +/- 17 days and a peak-to-peak amplitude of two magnituds, so a large light-travel-time effect is seen at 1 min radius. An attempt is made to use the LTTE to reconcile the discrepancy between the observations of Fazio et al. and Lester et al. regarding the far-infrared source size. This discrepancy is reviewed in light of recent, high-spatial-resolution observations at 11 microns by Danchi et al. We conclude that IRC +10216 has been resolved on the arcminute scale by Fazio et al. Convolution of the model intensity profile at 61 microns with the 60 sec x 90 sec Gaussian beam of Fazio et al. yields an observed source size full width at half maximum (FWHM) that ranges from approximately 67 sec to 75 sec depending on the phase of the star and the assumed distance to the source. Using a simple r(exp -2) dust distribution and the 106 deg phase of the Fazio et al. observations, the LTTE model reaches a peak size of 74.3 sec at a distance of 300 pc. This agrees favorably with the 78 sec x 6 sec size measured by Fazio et al. Finally, a method is outlined for using the LTTE as a distance indicator to IRC +10216 and other stars with extended mass outflows.

  18. Cosmological model dependence of the galaxy luminosity function: far-infrared results in the Lemaitre-Tolman-Bondi model

    CERN Document Server

    Iribarrem, A; Gruppioni, C; February, S; Ribeiro, M B; Berta, S; Floc'h, E Le; Magnelli, B; Nordon, R; Popesso, P; Pozzi, F; Riguccini, L

    2013-01-01

    This is the first paper of a series aiming at investigating galaxy formation and evolution in the giant-void class of the Lemaitre-Tolman-Bondi (LTB) models that best fits current cosmological observations. Here we investigate the Luminosity Function (LF) methodology, and how its estimates would be affected by a change on the cosmological model assumed in its computation. Are the current observational constraints on the allowed Cosmology enough to yield robust LF results? We use the far-infrared source catalogues built on the observations performed with the Herschel/PACS instrument, and selected as part of the PACS evolutionary probe (PEP) survey. Schechter profiles are obtained in redshift bins up to z approximately 4, assuming comoving volumes in both the standard model, that is, Friedmann-Lemaitre-Robertson-Walker metric with a perfect fluid energy-momentum tensor, and non-homogeneous LTB dust models, parametrized to fit the current combination of results stemming from the observations of supernovae Ia, th...

  19. Far-infrared and dc-Magnetotransport of CaMnO3 CaRuO3 Superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, P. [Max-Planck-Institut fur Feskorperforschung, Stuttgart, Germany; Boris, A. V. [Max-Planck-Institut fur Feskorperforschung, Stuttgart, Germany; Freeland, J. W. [Argonne National Laboratory (ANL); Kavich, J. J. [University of Illinois, Chicago; Chakhalian, J. [University of Arkansas; Lee, Ho Nyung [ORNL; Keimer, Bernhard [Max-Planck-Institut fur Feskorperforschung, Stuttgart, Germany

    2012-01-01

    We report temperature- and magnetic-field-dependent measurements of the dc resistivity and the far-infrared reflectivity (FIR) (photon energies {h_bar}{omega} = 50-700 cm{sup -1}) of superlattices comprising ten consecutive unit cells of the antiferromagnetic insulator CaMnO{sub 3}, and four to ten unit cells of the correlated paramagnetic metal CaRuO{sub 3}. Below the Neel temperature of CaMnO{sub 3}, the dc resistivity exhibits a logarithmic divergence upon cooling, which is associated with a large negative, isotropic magnetoresistance. The {omega} {yields} 0 extrapolation of the resistivity extracted from the FIR reflectivity, on the other hand, shows a much weaker temperature and field dependence. We attribute this behavior to scattering of itinerant charge carriers in CaRuO{sub 3} from sparse, spatially isolated magnetic defects at the CaMnO{sub 3}-CaRuO{sub 3} interfaces. This field-tunable 'transport bottleneck' effect may prove useful for functional metal-oxide devices.

  20. Effect of graphene on far-infrared transmission and absorption of FeF2 photonic crystals

    Science.gov (United States)

    Gao, Ying; Zhou, Sheng; Fu, Shufang

    2017-10-01

    The influence of graphene (Gr) on the far-infrared transmission and absorption of FeF2 photonic crystals (PCs) is investigated by the forth-order transfer matrix since Gr is anisotropic when the external field is perpendicular to the surface of PCs. The numerical results show that the transmission and absorption spectra largely depend on the structural symmetry of Gr/FeF2 PCs and the position of Gr layer. The optimal structure and number of dielectric bi-layers (N) are discussed. In addition, the introduction of Gr leads to the disappearance of the defect modes in the band gap. Meanwhile, the line width of absorption around of the resonant frequencies of FeF2 has been extremely broadened, which is compared with the one of FeF2 PCs. Once N is beyond a critical value, the absorber will become the reflector. The effect of Fermi energy and external field on the absorption is also investigated.

  1. The Deep SPIRE HerMES Survey: Spectral Energy Distributions and their Astrophysical Indications at High Redshift

    CERN Document Server

    Brisbin, D; Altieri, B; Amblard, A; Arumugam, V; Aussel, H; Babbedge, T; Blain, A; Bock, J; Boselli, A; Buat, V; Castro-Rodríguez, N; Cava, A; Chanial, P; Clements, D L; Conley, A; Conversi, L; Cooray, A; Dowell, C D; Dwek, E; Eales, S; Elbaz, D; Fox, M; Franceschini, A; Gear, W; Glenn, J; Griffin, M; Halpern, M; Hatziminaoglou, E; Ibar, E; Isaak, K; Ivison, R J; Lagache, G; Levenson, L; Lonsdale, Carol J; Lu, N; Madden, S; Maffei, B; Mainetti, G; Marchetti, L; Morrison, G E; Nguyen, H T; O’Halloran, B; Oliver, S J; Omont, A; Owen, F N; Pannella, M; Panuzzo, P; Papageorgiou, A; Pearson, C P; Pérez-Fournon, I; Pohlen, M; Rizzo, D; Roseboom, I G; Rowan-Robinson, M; Portal, M Sánchez; Schulz, B; Seymour, N; Shupe, D L; Smith, A J; Stevens, J A; Strazzullo, V; Symeonidis, M; Trichas, M; Tugwell, K E; Vaccari, M; Valtchanov, I; Vigroux, L; Wang, L; Ward, R; Wright, G; Xu, C K; Zemcov, M

    2010-01-01

    The Spectral and Photometric Imaging Receiver (SPIRE) on Herschel has been carrying out deep extragalactic surveys, one of whose aims is to establish spectral energy distributions (SED)s of individual galaxies spanning the infrared/submillimeter (IR/SMM) wavelength region. We report observations of the (IR/SMM) emission from the Lockman North field (LN) and Great Observatories Origins Deep Survey field North (GOODS-N). Because galaxy images in the wavelength range covered by Herschel generally represent a blend with contributions from neighboring galaxies, we present sets of galaxies in each field especially free of blending at 250, 350, and 500 microns. We identify the cumulative emission of these galaxies and the fraction of the far infrared cosmic background radiation they contribute. Our surveys reveal a number of highly luminous galaxies at redshift z ∼< 3 and a novel relationship between infrared and visible emission that shows a dependence on luminosity and redshift.

  2. What produces the far-infrared/submillimetre emission in the most luminous QSOs?

    Science.gov (United States)

    Symeonidis, M.

    2017-02-01

    The AGN. I examine the average spectral energy distributions (SEDs) of two samples of the most powerful, unobscured quasi-stellar objects (QSOs) at 2 infrared (IR) luminosity, removing the necessity for a star-forming component in the far-IR/submm. I argue that the origin of the far-IR/submm emission in such powerful QSOs includes a small contribution from the AGN torus but is predominantly linked to dust at kpc-scales heated by the AGN. The latter component accounts for at least 5-10 per cent of the bolometric AGN luminosity and has an implied dust mass of the order of 108 M⊙.

  3. Generation of frequency-chirped pulses in the far-infrared by means of a sub-picosecond free-electron laser and an external pulse shaper

    Science.gov (United States)

    Knippels, G. M. H.; van der Meer, A. F. G.; Mols, R. F. X. A. M.; van Amersfoort, P. W.; Vrijen, R. B.; Maas, D. J.; Noordam, L. D.

    1995-02-01

    The generation of frequency-chirped optical pulses in the far-infrared is reported. The pulses are produced by the free-electron laser FELIX. The chirp is induced by means of an external shaping device consisting of a grating and a telescope. The shaper is based on reflective optics to permit operation in a wide spectral range. The present experiments were made at 8.2 μm wavelength. The fwhm duration of the incident pulse was 0.50 ps, which corresponds to a bandwidth of 2.2%. It has been checked that a linear chirp is produced, for the case that the frequency increases from the leading edge of the pulse to the trailing edge, as well as for the reverse case. This is accompanied by an increase of the fwhm pulse duration which ranges up to 16.5 ps.

  4. Modelling the spectral energy distribution of galaxies. V. The dust and PAH emission SEDs of disk galaxies

    CERN Document Server

    Popescu, Cristina C; Dopita, Michael A; Fischera, Joerg; Kylafis, Nikolaos D; Madore, Barry F

    2010-01-01

    We present a self-consistent model of the spectral energy distributions (SEDs) of spiral galaxies from the ultraviolet (UV) to the mid-infrared (MIR)/far-infrared (FIR)/submillimeter (submm) based on a full radiative transfer calculation of the propagation of starlight in galaxy disks. This model predicts not only the total integrated energy absorbed in the UV/optical and re-emitted in the infrared/submm, but also the colours of the dust emission based on an explicit calculation of the strength and colour of the UV/optical radiation fields heating the dust, and incorporating a full calculation of the stochastic heating of small dust grains and PAH molecules. The geometry of the translucent components of the model is empirically constrained using the results from the radiation transfer analysis of Xilouris et al. on spirals in the middle range of the Hubble sequence, while the geometry of the optically thick components is constrained from physical considerations with a posteriori checks of the model prediction...

  5. Far-Infrared Emission Characteristics and Wear Comfort Property of ZrC-Imbedded Heat Storage Knitted Fabrics for Emotional Garments

    Directory of Open Access Journals (Sweden)

    Kim Hyun Ah

    2017-06-01

    Full Text Available This study examined the far-infrared emission characteristics and wear comfort properties of ZrC-imbedded heat storage knitted fabrics. For this purpose, ZrC-imbedded, heat storage PET (polyethylene terephthalate was spun from high-viscosity PET with imbedded ZrC powder on the core part and low-viscosity PET on the sheath part using a conjugated spinning method. ZrC-imbedded PET knitted fabric was also prepared and its physical properties were measured and compared with those of regular PET knitted fabric. In addition, ingredient analysis and the far-infrared emission characteristics of the ZrC-imbedded knitted fabrics were analyzed by energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The thermal properties, moisture absorption, and drying properties of the ZrC-imbedded PET knitted fabric were measured and compared with those of the regular PET knitted fabric. The mechanical properties using the FAST (fabric assurance by simple testing system and the dye affinity of the ZrC-imbedded knitted fabric were also measured and compared with those of regular PET knitted fabric.

  6. Atrazine molecular imprinted polymers: comparative analysis by far-infrared and ultraviolet induced polymerization.

    Science.gov (United States)

    Chen, Jun; Bai, Lian-Yang; Liu, Kun-Feng; Liu, Run-Qiang; Zhang, Yu-Ping

    2014-01-06

    Atrazine molecular imprinted polymers (MIPs) were comparatively synthesized using identical polymer formulation by far-infrared (FIR) radiation and ultraviolet (UV)-induced polymerization, respectively. Equilibrium binding experiments were carried out with the prepared MIPs; the results showed that MIP(uv) possessed specific binding to atrazine compared with their MIP(FIR) radiation counterparts. Scatchard plot's of both MIPs indicated that the affinities of the binding sites in MIPs are heterogeneous and can be approximated by two dissociation-constants corresponding to the high- and low-affinity binding sites. Moreover, several common pesticides including atrazine, cyromazine, metamitron, simazine, ametryn, terbutryn were tested to determine their specificity, similar imprinting factor (IF) and different selectivity index (SI) for both MIPs. Physical characterization of the polymers revealed that the different polymerization methods led to slight differences in polymer structures and performance by scanning electron microscope (SEM), Fourier transform infrared absorption (FT-IR), and mercury analyzer (MA). Finally, both MIPs were used as selective sorbents for solid phase extraction (SPE) of atrazine from lake water, followed by high performance liquid chromatography (HPLC) analysis. Compared with commercial C18 SPE sorbent (86.4%-94.8%), higher recoveries of atrazine in spiked lake water were obtained in the range of 90.1%-97.1% and 94.4%-101.9%, for both MIPs, respectively.

  7. Herschel Observations of Far-Infrared Cooling Lines in intermediate Redshift (Ultra)-luminous Infrared Galaxies

    CERN Document Server

    Rigopoulou, D; Magdis, G E; Thatte, N; Swinyard, B M; Farrah, D; Huang, J-S; Alonso-Herrero, A; Bock, J J; Clements, D; Cooray, A; Griffin, M J; Oliver, S; Pearson, C; Riechers, D; Scott, D; Smith, A; Vaccari, M; Valtchanov, I; Wang, L

    2014-01-01

    We report the first results from a spectroscopic survey of the [CII] 158um line from a sample of intermediate redshift (0.210^11.5 Lsun), using the SPIRE-Fourier Transform Spectrometer (FTS) on board the Herschel Space Observatory. This is the first survey of [CII] emission, an important tracer of star-formation, at a redshift range where the star-formation rate density of the Universe increases rapidly. We detect strong [CII] 158um line emission from over 80% of the sample. We find that the [CII] line is luminous, in the range (0.8-4)x10^(-3) of the far-infrared continuum luminosity of our sources, and appears to arise from photodissociation regions on the surface of molecular clouds. The L[CII]/LIR ratio in our intermediate redshift (U)LIRGs is on average ~10 times larger than that of local ULIRGs. Furthermore, we find that the L[CII]/LIR and L[CII]/LCO(1-0) ratios in our sample are similar to those of local normal galaxies and high-z star-forming galaxies. ULIRGs at z~0.5 show many similarities to the prop...

  8. Far-Infrared Dust Temperatures and Column Densities of the MALT90 Molecular Clump Sample

    CERN Document Server

    Guzmán, Andrés E; Contreras, Yanett; Smith, Howard A; Jackson, James M; Hoq, Sadia; Rathborne, Jill M

    2015-01-01

    We present dust column densities and dust temperatures for $\\sim3000$ young high-mass molecular clumps from the Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey, derived from adjusting single temperature dust emission models to the far-infrared intensity maps measured between 160 and 870 \\micron\\ from the Herschel/Hi-Gal and APEX/ATLASGAL surveys. We discuss the methodology employed in analyzing the data, calculating physical parameters, and estimating their uncertainties. The population average dust temperature of the clumps are: $16.8\\pm0.2$ K for the clumps that do not exhibit mid-infrared signatures of star formation (Quiescent clumps), $18.6\\pm0.2$ K for the clumps that display mid-infrared signatures of ongoing star formation but have not yet developed an HII region (Protostellar clumps), and $23.7\\pm0.2$ and $28.1\\pm0.3$ K for clumps associated with HII and photo-dissociation regions, respectively. These four groups exhibit large overlaps in their temperature distributions, with dispersions rang...

  9. Evolution of the Far-Infrared Cloud at Titan's South Pole

    Science.gov (United States)

    Jennings, Donald E.; Achterberg, R. K.; Cottini, V.; Anderson, C. M.; Flasar, F. M.; Nixon, C. A.; Bjoraker, G. L.; Kunde, V. G.; Carlson, R. C.; Guandique, E.; Kaelberer, M. S.; Tingley, J. S.; Albright, S. A.; Segura, M. E.; de Kok, R.; Coustenis, A.; Vinatier, S.; Bampasidis, G.; Teanby, N. A.; Calcutt, S.

    2015-01-01

    A condensate cloud on Titan identified by its 220 cm (sup -1) far-infrared signature continues to undergo seasonal changes at both the north and south poles. In the north the cloud, which extends from 55 North to the pole, has been gradually decreasing in emission intensity since the beginning of the Cassini mission with a half-life of 3.8 years. The cloud in the south did not appear until 2012 but its intensity has increased rapidly, doubling every year. The shape of the cloud at the South Pole is very different from that in the north. Mapping in December 2013 showed that the condensate emission was confined to a ring with a maximum at 80 South. The ring was centered 4 degrees from Titan's pole. The pattern of emission from stratospheric trace gases like nitriles and complex hydrocarbons (mapped in January 2014) was also offset by 4 degrees, but had a central peak at the pole and a secondary maximum in a ring at about 70 South with a minimum at 80 South. The shape of the gas emissions distribution can be explained by abundances that are high at the atmospheric pole and diminish toward the equator, combined with correspondingly increasing temperatures. We discuss possible causes for the condensate ring. The present rapid build up of the condensate cloud at the South Pole is likely to transition to a gradual decline during 2015-16.

  10. Far Infrared Luminosity Function of Local Star-forming Galaxies in the AKARI Deep Field South

    CERN Document Server

    Sedgwick, Chris; Pearson, Chris; Matsuura, Shuji; Shirahata, Mai; Oyabu, Shinki; Goto, Tomotsugu; Matsuhara, Hideo; Clements, D L; Negrello, Mattia; White, Glenn J

    2011-01-01

    We present a far-infrared galaxy luminosity function for the local universe. We have obtained 389 spectroscopic redshifts for galaxies observed at 90 microns in the AKARI Deep Field South, using the AAOmega fibre spectrograph via optical identifications in the digitized sky survey and 4m-class optical imaging. For the luminosity function presented in this paper, we have used those galaxies which have redshifts 0

  11. HAWCPol: a first-generation far-infrared polarimeter for SOFIA

    Science.gov (United States)

    Dowell, C. Darren; Cook, Brant T.; Harper, D. Al; Lin, Lung-Sheng; Looney, Leslie W.; Novak, Giles; Stephens, Ian; Berthoud, Marc; Chuss, David T.; Crutcher, Richard M.; Dotson, Jessie L.; Hildebrand, Roger H.; Houde, Martin; Jones, Terry J.; Krejny, Megan; Lazarian, Alexandre; Moseley, S. Harvey; Tassis, Kostas; Vaillancourt, John E.; Werner, Michael W.

    2010-07-01

    We describe our ongoing project to build a far-infrared polarimeter for the HAWC instrument on SOFIA. Far-IR polarimetry reveals unique information about magnetic fields in dusty molecular clouds and is an important tool for understanding star formation and cloud evolution. SOFIA provides flexible access to the infrared as well as good sensitivity to and angular resolution of continuum emission from molecular clouds. We are making progress toward outfitting HAWC, a first-generation SOFIA camera, with a four-band polarimeter covering 50 to 220 microns wavelength. We have chosen a conservative design which uses quartz half-wave plates continuously rotating at ~0.5 Hz, ball bearing suspensions, fixed wire-grid polarizers, and cryogenic motors. Design challenges are to fit the polarimeter into a volume that did not originally envision one, to minimize the heating of the cryogenic optics, and to produce negligible interference in the detector system. Here we describe the performance of the polarimeter measured at cryogenic temperature as well as the basic method we intend for data analysis. We are on track for delivering this instrument early in the operating lifetime of SOFIA.

  12. HERSCHEL FAR-INFRARED PHOTOMETRIC MONITORING OF PROTOSTARS IN THE ORION NEBULA CLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    Billot, N. [NASA Herschel Science Center, California Institute of Technology, 770 S. Wilson Ave, Pasadena, CA 91125 (United States); Morales-Calderon, M.; Stauffer, J. R. [Spitzer Science Center, Caltech, Pasadena, CA 91125 (United States); Megeath, S. T. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Whitney, B., E-mail: billot@iram.es [Space Science Institute, Boulder, CO 80301 (United States)

    2012-07-10

    We have obtained time series observations of the Orion Nebula Cluster at 70 {mu}m and 160 {mu}m from the Herschel/PACS Photometer. This represents the first wide-field far-infrared photometric monitoring of a young star-forming region. The acquired 35' Multiplication-Sign 35' maps show complex extended structures, with unprecedented detail, that trace the interaction between the molecular gas and the young hot stars. We detect 43 protostars, most of which are situated along the integral-shaped filament extending from the Orion nebula, through OMC 2 and OMC 3. We present high-reliability light curves for some of these objects using the first six epochs of our observing program spread over 6 weeks. We find amplitude variations in excess of 20% for a fraction of the detected protostars over periods as short as a few weeks. This is inconsistent with the dynamical timescales of cool far-IR emitting material that orbits at hundreds of AU from the protostar, and it suggests that the mechanism(s) responsible for the observed variability originates from the inner region of the protostars, likely driven by variable mass accretion.

  13. Extended Far-Infrared CO Emission in the OMC-1 Core of Orion.

    Science.gov (United States)

    Sempere; Cernicharo; Lefloch; González-Alfonso; Leeks

    2000-02-20

    We report on sensitive far-infrared observations of 12CO pure rotational transitions in the OMC-1 core of Orion. The lines were observed with the long-wavelength spectrometer in the grating mode on board the Infrared Space Observatory, covering the 43-197 µm wavelength range. The transitions from Jup=14 up to Jup=19 have been identified across the whole OMC-1 core, and lines up to Jup=43 have been detected toward the central region, KL/IRc2. In addition, we have taken high-quality spectra in the Fabry-Perot mode of some of the CO lines. In KL/IRc2, the lines are satisfactorily accounted for by a three-temperature model describing the plateau and ridge emission. The fluxes detected in the high-J transitions (Jup>34) reveal the presence of a very hot and dense gas component [T=1500-2500 K; N&parl0;CO&parr0;=2x1017 cm-2], probably originating from some of the embedded sources previously observed in the H2 near-infrared lines. At all other positions in the OMC-1 core, we estimate kinetic temperatures >/=80 K and as high as 150 K at some positions around IRc2, from a simple large-velocity gradient model.

  14. Atrazine Molecular Imprinted Polymers: Comparative Analysis by Far-Infrared and Ultraviolet Induced Polymerization

    Directory of Open Access Journals (Sweden)

    Jun Chen

    2014-01-01

    Full Text Available Atrazine molecular imprinted polymers (MIPs were comparatively synthesized using identical polymer formulation by far-infrared (FIR radiation and ultraviolet (UV-induced polymerization, respectively. Equilibrium binding experiments were carried out with the prepared MIPs; the results showed that MIPuv possessed specific binding to atrazine compared with their MIPFIR radiation counterparts. Scatchard plot’s of both MIPs indicated that the affinities of the binding sites in MIPs are heterogeneous and can be approximated by two dissociation-constants corresponding to the high- and low-affinity binding sites. Moreover, several common pesticides including atrazine, cyromazine, metamitron, simazine, ametryn, terbutryn were tested to determine their specificity, similar imprinting factor (IF and different selectivity index (SI for both MIPs. Physical characterization of the polymers revealed that the different polymerization methods led to slight differences in polymer structures and performance by scanning electron microscope (SEM, Fourier transform infrared absorption (FT-IR, and mercury analyzer (MA. Finally, both MIPs were used as selective sorbents for solid phase extraction (SPE of atrazine from lake water, followed by high performance liquid chromatography (HPLC analysis. Compared with commercial C18 SPE sorbent (86.4%–94.8%, higher recoveries of atrazine in spiked lake water were obtained in the range of 90.1%–97.1% and 94.4%–101.9%, for both MIPs, respectively.

  15. A tapered undulator experiment at the ELBE far infrared hybrid-resonator oscillator free electron laser.

    Science.gov (United States)

    Asgekar, V; Lehnert, U; Michel, P

    2012-01-01

    A tapered undulator experiment was carried out at the ELBE far-infrared free electron laser (FEL). The oscillator FEL makes use of a hybrid optical resonator. The main motivation was to see whether the presence of a dispersive medium in the form of a waveguide in the resonator has any effect on the outcome. The FEL saturated power and the wavelength shifts have been measured as a function of both positive as well as negative undulator field amplitude tapering. In contrast to the typical high-gain FELs where positive tapering proves beneficial for the output power we observed an improvement of performance at negative taper. During the same experiments we studied the characteristics of the detuning curves. The width of the curves indicates a maximum small signal gain for zero taper while the output peak power increases with negative taper. The saturated power output, the detuning curve characteristics, and the wavelength shifts agrees with the theoretical predictions. Details of the experiment are presented.

  16. Far-infrared and dust properties of present-day galaxies in the EAGLE simulations

    CERN Document Server

    Camps, Peter; Baes, Maarten; Theuns, Tom; Schaller, Matthieu; Schaye, Joop

    2016-01-01

    The EAGLE cosmological simulations reproduce the observed galaxy stellar mass function and many galaxy properties. In this work, we study the dust-related properties of present-day EAGLE galaxies through mock observations in the far-infrared and submm wavelength ranges obtained with the 3D dust radiative transfer code SKIRT. To prepare an EAGLE galaxy for radiative transfer processing, we derive a diffuse dust distribution from the gas particles and we re-sample the star-forming gas particles and the youngest star particles into star-forming regions that are assigned dedicated emission templates. We select a set of redshift-zero EAGLE galaxies that matches the K-band luminosity distribution of the galaxies in the Herschel Reference Survey (HRS), a volume-limited sample of about 300 normal galaxies in the Local Universe. We find overall agreement of the EAGLE dust scaling relations with those observed in the HRS, such as the dust-to-stellar mass ratio versus stellar mass and versus NUV-r colour relations. A di...

  17. Far Infrared Mapping of Three Galactic Star Forming Regions: W3(OH), S209 & S187

    Indian Academy of Sciences (India)

    S. K. Ghosh; B. Mookerjea; T. N. Rengarajan; S. N. Tandon; R. P. Verma

    2001-06-01

    Three Galactic star forming regions associated with W3(OH), S209 and S187 have been simultaneously mapped in two trans-IRAS far infrared (FIR) bands centered at ∼ 140 and 200m using the TIFR 100 cm balloon borne FIR telescope. These maps showextended FIR emission with structures. The HIRES processed IRAS maps of these regions at 12, 25, 60 & 100 m have also been presented for comparison. Point-like sources have been extracted from the longest waveband TIFR maps and searched for associations in the other five bands. The diffuse emission from these regions have been quantified, which turns out to be a significant fraction of the total emission. The spatial distribution of cold dust (T < 30 K) for two of these sources (W3(OH) & S209), has been determined reliably from the maps in TIFR bands. The dust temperature and optical depth maps show complex morphology. In general the dust around S209 has been found to be warmer than that in W3(OH) region.

  18. The AU Mic Debris Disk: far-infrared and submillimeter resolved imaging

    CERN Document Server

    Matthews, Brenda C; Sibthorpe, Bruce; Holland, Wayne; Booth, Mark; Kalas, Paul; MacGregor, Meredith; Wilner, David; Vandenbussche, Bart; Olofsson, Göran; Blommaert, Joris; Brandeker, Alexis; Dent, W R F; de Vries, Bernard L; Di Francesco, James; Fridlund, Malcolm; Graham, James R; Greaves, Jane; Heras, Ana M; Hogerheijde, Michiel; Ivison, R J; Pantin, Eric; Pilbratt, Göran L

    2015-01-01

    We present far-infrared and submillimeter maps from the Herschel Space Observatory and the James Clerk Maxwell Telescope of the debris disk host star AU Microscopii. Disk emission is detected at 70, 160, 250, 350, 450, 500 and 850 micron. The disk is resolved at 70, 160 and 450 micron. In addition to the planetesimal belt, we detect thermal emission from AU Mic's halo for the first time. In contrast to the scattered light images, no asymmetries are evident in the disk. The fractional luminosity of the disk is $3.9 \\times 10^{-4}$ and its mm-grain dust mass is 0.01 MEarth (+/- 20%). We create a simple spatial model that reconciles the disk SED as a blackbody of 53 +/- 2 K (a composite of 39 and 50 K components) and the presence of small (non-blackbody) grains which populate the extended halo. The best fit model is consistent with the "birth ring" model explored in earlier works, i.e., an edge-on dust belt extending from 8.8-40 AU, but with an additional halo component with an $r^{-1.5}$ surface density profile...

  19. EVOLUTION OF THE FAR-INFRARED CLOUD AT TITAN’S SOUTH POLE

    Energy Technology Data Exchange (ETDEWEB)

    Jennings, Donald E.; Achterberg, R. K.; Cottini, V.; Anderson, C. M.; Flasar, F. M.; Nixon, C. A.; Bjoraker, G. L.; Kunde, V. G.; Carlson, R. C.; Guandique, E.; Kaelberer, M. S.; Tingley, J. S.; Albright, S. A.; Segura, M. E. [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kok, R. de [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Coustenis, A.; Vinatier, S.; Bampasidis, G. [Laboratoire d’Etudes Spatiales et d’Instrumentation en Astrophysique (LESIA), Observatoire de Paris, CNRS, UPMC Univ. Paris 06, Univ. Paris-Diderot, 5, place Jules Janssen, F-92195 Meudon Cedex (France); Teanby, N. A. [School of Earth Sciences, University of Bristol, Bristol BS8 1RJ (United Kingdom); Calcutt, S., E-mail: donald.e.jennings@nasa.gov [Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

    2015-05-10

    A condensate cloud on Titan identified by its 220 cm{sup −1} far-infrared signature continues to undergo seasonal changes at both the north and south poles. In the north, the cloud, which extends from 55 N to the pole, has been gradually decreasing in emission intensity since the beginning of the Cassini mission with a half-life of 3.8 years. The cloud in the south did not appear until 2012 but its intensity has increased rapidly, doubling every year. The shape of the cloud at the south pole is very different from that in the north. Mapping in 2013 December showed that the condensate emission was confined to a ring with a maximum at 80 S. The ring was centered 4° from Titan's pole. The pattern of emission from stratospheric trace gases like nitriles and complex hydrocarbons (mapped in 2014 January) was also offset by 4°, but had a central peak at the pole and a secondary maximum in a ring at about 70 S with a minimum at 80 S. The shape of the gas emission distribution can be explained by abundances that are high at the atmospheric pole and diminish toward the equator, combined with correspondingly increasing temperatures. We discuss possible causes for the condensate ring. The present rapid build up of the condensate cloud at the south pole is likely to transition to a gradual decline from 2015 to 2016.

  20. Regolith grain sizes of Saturn's rings inferred from Cassini-CIRS far-infrared spectra

    CERN Document Server

    Morishima, Ryuji; Spilker, Linda

    2012-01-01

    We analyze far-infrared (10-650 cm$^{-1}$) emissivity spectra of Saturn's main rings obtained by the Cassini Composite Infrared Spectrometer (CIRS). In modeling of the spectra, the single scattering albedos of regolith grains are calculated using the Mie theory, diffraction is removed with the delta-Eddington approximation, and the hemispherical emissivities of macroscopic free-floating ring particles are calculated using the Hapke's isotropic scattering model. Only pure crystalline water ice is considered and the size distribution of regolith grains is estimated. We find that good fits are obtained if the size distribution is broad ranging from 1 $\\mu$m to 1-10 cm with a power law index of $ \\sim 3$. This means that the largest regolith grains are comparable to the smallest free-floating particles in size and that the power law indices for both free-floating particles and regolith grains are similar to each other. The apparent relative abundance of small grains increases with decreasing solar phase angle (or...

  1. Far-infrared emission in luminous quasars accompanied by nuclear outflows

    Science.gov (United States)

    Maddox, Natasha; Jarvis, M. J.; Banerji, M.; Hewett, P. C.; Bourne, N.; Dunne, L.; Dye, S.; Eales, S.; Furlanetto, C.; Maddox, S. J.; Smith, M. W. L.; Valiante, E.

    2017-09-01

    Combining large-area optical quasar surveys with the new far-infrared (FIR) Herschel-ATLAS Data Release 1, we search for an observational signature associated with the minority of quasars possessing bright FIR luminosities. We find that FIR-bright quasars show broad C IV emission-line blueshifts in excess of that expected from the optical luminosity alone, indicating particularly powerful nuclear outflows. The quasars show no signs of having redder optical colours than the general ensemble of optically selected quasars, ruling out differences in line-of-sight dust within the host galaxies. We postulate that these objects may be caught in a special evolutionary phase, with unobscured, high black hole accretion rates and correspondingly strong nuclear outflows. The high FIR emission found in these objects is then either a result of star formation related to the outflow, or is due to dust within the host galaxy illuminated by the quasar. We are thus directly witnessing coincident small-scale nuclear processes and galaxy-wide activity, commonly invoked in galaxy simulations that rely on feedback from quasars to influence galaxy evolution.

  2. Inhibitory Effects of Far-Infrared Irradiation Generated by Ceramic Material on Murine Melanoma Cell Growth

    Directory of Open Access Journals (Sweden)

    Ting-Kai Leung

    2012-01-01

    Full Text Available The biological effects of specific wavelengths, so-called “far-infrared radiation” produced from ceramic material (cFIR, on whole organisms are not yet well understood. In this study, we investigated the biological effects of cFIR on murine melanoma cells (B16-F10 at body temperature. cFIR irradiation treatment for 48 h resulted in an 11.8% decrease in the proliferation of melanoma cells relative to the control. Meanwhile, incubation of cells with cFIR for 48 h significantly resulted in 56.9% and 15.7% decreases in the intracellular heat shock protein (HSP70 and intracellular nitric oxide (iNO contents, respectively. Furthermore, cFIR treatment induced 6.4% and 12.3% increases in intracellular reactive oxygen species stained by 5-(and 6-carboxyl-2′,7′-dichlorodihydrofluorescein diacetate and dihydrorhodamine 123, respectively. Since malignant melanomas are known to have high HSP70 expression and iNO activity, the suppressive effects of cFIR on HSP70 and NO may warrant future interest in antitumor applications.

  3. GaAs Blocked-Impurity-Band Detectors for Far-Infrared Astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Cardozo, Benjamin Lewin

    2004-12-21

    High-purity and doped GaAs films have been grown by Liquid-phase epitaxy (LPE) for development of a blocked impurity band (BIB) detector for far-infrared radiation. The film growth process developed has resulted in the capability to grow GaAs with a net active impurity concentration below 1 x 10{sup 13} cm{sup -3}, ideal for the blocking layer of the BIB detector. The growth of n-type LPE GaAs films with donor concentrations below the metal-insulator transition, as required for the absorbing layer of a BIB detector, has been achieved. The control of the donor concentration, however, was found to be insufficient for detector production. The growth by LPE of a high-purity film onto a commercially grown vapor-phase epitaxial (VPE) n-type GaAs doped absorbing layer resulted in a BIB device that showed a significant reduction in the low-temperature dark current compared to the absorbing layer only. Extended optical response was not detected, most likely due to the high compensation of the commercially grown GaAs absorbing layer, which restricts the depletion width of the device.

  4. Micro-Spec: An Ultracompact, High-sensitivity Spectrometer for Far-Infrared and Submillimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe; Hsieh, Wen-Ting; Huang, Wei-Chung; Moseley, S. Harvey; Stevenson, Thomas R.; Wollack, Edward J.

    2014-01-01

    High-performance, integrated spectrometers operating in the far-infrared and submillimeter ranges promise to be powerful tools for the exploration of the epochs of reionization and initial galaxy formation. These devices, using high-efficiency superconducting transmission lines, can achieve the performance of a meter-scale grating spectrometer in an instrument implemented on a 4 inch silicon wafer. Such a device, when combined with a cryogenic telescope in space, provides an enabling capability for studies of the early universe. Here, the optical design process for Micro-Spec (micron-Spec) is presented, with particular attention given to its two-dimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the stigmatization and minimization of the light path function in this bounded region, which results in an optimized geometrical configuration. A point design with an efficiency of (is) approximately 90% has been developed for initial demonstration and can serve as the basis for future instruments. Design variations on this implementation are also discussed, which can lead to lower efficiencies due to diffractive losses in the multimode region.

  5. Far-infrared estimates of the mass of gas in the Galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Broadbent, A.; MacLaren, I.; Wolfendale, A.W.

    1989-04-15

    An analysis has been made of the available far-infrared (FIR) data in the wavelength range 60-250 /mu/m along the Galactic Plane to study the distribution of the mass of gas in molecular form in the Inner Galaxy. A model is used in which the dust-to-gas ratio increases slowly towards the Galactic Centre, in a manner proportional to metallicity, and a number of other assumptions are made that are shown to be reasonable from comparison with the well known H I component locally. The total FIR emission is attributed to three basic components, viz. dust associated with H I, H II and H/sub 2/, each of which has its own temperature as a function of Galactic longitude. By achieving a best fit to all the data at each wavelength it is possible to isolate the H/sub 2/ component for detailed study. The result is that the total mass of the H/sub 2/ in the Inner Galaxy is (6.1 +- 2.7) x 10/sup 8/ solar masses. (author).

  6. Detection of Far-Infrared Features in Star-Forming Regions

    CERN Document Server

    Onaka, T; Onaka, Takashi; Okada, Yoko

    2003-01-01

    We report the detection of a feature at 65um and a broad feature around 100um in the far-infrared spectra of the diffuse emission from two active star-forming regions, the Carina nebula and Sharpless 171. The features are seen in the spectra over a wide area of the observed regions, indicating that the carriers are fairly ubiquitous species in the interstellar medium. A similar 65um feature has been detected in evolved stars and attributed to diopside, a Ca-bearing crystalline silicate. The present observations indicate the first detection of a crystalline silicate in the interstellar medium if this identification holds true also for the interstellar feature. A similar broad feature around 90um reported in the spectra of evolved stars has been attributed to calcite, a Ca-bearing carbonate mineral. The interstellar feature seems to be shifted to longer wavelengths and have a broader width although the precise estimate of the feature profile is difficult. As a carrier for the interstellar 100um feature, we inve...

  7. Far-infrared multi-resonant graphene-based metamaterial absorber

    Science.gov (United States)

    Parvaz, Reza; Karami, Hamidreza

    2017-08-01

    Recent developments in metamaterial designs have opened up the possibility of absorption in the terahertz frequency range. In this paper, a multi-resonant absorber is presented in which the resonance frequencies are theoretically organized by doping graphene ribbons with a ring-shaped gold on each ribbon per unit cell. This action allows the free electrons to flow on a piece of graphene surface to produce several absorption peaks in the far-infrared spectrum. Besides, in order to adjust the absorber to respond at different and wide frequency spectra, the absorption peaks can be managed by manipulating the gate voltage and dielectric thickness. This periodic structure also consists of a dielectric substrate of silicon dioxide and a metal slab at its back to ensure the zero transmission. Moreover, the equivalent circuit and transmission line model are derived based on the reflected fields and vector-fitting method to facilitate analysis of the proposed design and evaluation of the full-wave simulation results. At the end, the sensitivity of the absorption against oblique incidence is studied for both TE and TM polarizations.

  8. Rotation-Vibration Spectra of Malonaldehyde Obtained with Far-Infrared Synchrotron Radiation

    Science.gov (United States)

    Tokaryk, D. W.; Ross, S. C.; Forthomme, D.; Prescott, J. E.; Yamada, K. M. T.; Ito, F.

    2011-06-01

    Malonaldehyde is an open 5-membered ring molecule which exhibits interesting quantum-mechancial effects due to tunnelling of one of its protons. This results in a 21 Cm-1 tunnelling-splitting in the ground vibrational state, which has been well-studied by microwave spectroscopy. We have taken far-infrared Fourier transform spectra of malonaldehyde at the Canadian Light Source synchrotron, and have recorded a number of rotation-vibration fundamental bands between 100-1000 Cm-1 at 0.00096 Cm-1 resolution. The data permit us to determine with high precision the changes in the tunnelling-splitting induced by vibrational excitation. We have also observed spectra at 240 and 219 Cm-1 that appear to be transitions from the two components of the ground vibrational state to a common upper state that is not mentioned in conventional vibrational analyses of malonaldehyde. We will offer suggestions as to the nature of the newly-observed state. P. Turner, S. L. Baughcum, S. L. Coy and Z. Smith, J. Am. Chem. Soc. 106 (1984) 2265-2267 T. Baba, T. Tanaka, I. Morino, K. M. T. Yamada and K. Tanaka, J. Chem. Phys. 110 (1999) 4131-4133. A. Alparone and S. Millefiori, Chem. Phys. 290 (2003) 15-25.

  9. Far-Infrared Properties of Lyman Break Galaxies from Cosmological Simulations

    CERN Document Server

    Cen, Renyue

    2011-01-01

    Utilizing state-of-the-art, adaptive mesh-refinement cosmological hydrodynamic simulations with ultra-high resolution (114h-1pc) and large sample size (>3300 galaxies of stellar mass >10^9Msun), we show how the stellar light of Lyman Break Galaxies at z=2 is distributed between optical/ultra-violet (UV) and far-infrared (FIR) bands. With a single scalar parameter for dust obscuration we can simultaneously reproduce the observed UV luminosity function for the entire range (3-100 Msun/yr) and extant FIR luminosity function at the bright end (>20Msun/yr). We quantify that galaxies more massive or having higher SFR tend to have larger amounts of dust obscuration mostly due to a trend in column density and in a minor part due to a mass (or SFR)-metallicity relation. It is predicted that the FIR luminosity function in the range SFR=1-100Msun/yr is a powerlaw with a slope about -1.7. We further predict that there is a "galaxy desert" at SFR(FIR) < 0.02 (SFR(UV)/10Msun/yr)^2.1 Msun/yr in the SFR(UV)-SFR(FIR) plane...

  10. Far-infrared spectroscopy of a lensed starburst: a blind redshift from Herschel

    CERN Document Server

    George, R D; Hopwood, R; Riechers, D A; Bussmann, R S; Cox, P; Dye, S; Krips, M; Negrello, M; Neri, R; Serjeant, S; Valtchanov, I; Baes, M; Bourne, N; Clements, D L; De Zotti, G; Dunne, L; Eales, S A; Ibar, E; Maddox, S; Smith, M W L; Valiante, E; van der Werf, P

    2013-01-01

    We report the redshift of HATLAS J132427.0+284452 (hereafter HATLAS J132427), a gravitationally lensed starburst galaxy, the first determined 'blind' by the Herschel Space Observatory. This is achieved via the detection of [C II] consistent with z = 1.68 in a far-infrared spectrum taken with the SPIRE Fourier Transform Spectrometer. We demonstrate that the [C II] redshift is secure via detections of CO J = 2 - 1 and 3 - 2 using the Combined Array for Research in Millimeter-wave Astronomy and the Institut de Radioastronomie Millimetrique's Plateau de Bure Interferometer. The intrinsic properties appear typical of high-redshift starbursts despite the high lensing-amplified fluxes, proving the ability of the FTS to probe this population with the aid of lensing. The blind detection of [C II] demonstrates the potential of the SAFARI imaging spectrometer, proposed for the much more sensitive SPICA mission, to determine redshifts of multiple dusty galaxies simultaneously without the benefit of lensing.

  11. H-ATLAS: THE COSMIC ABUNDANCE OF DUST FROM THE FAR-INFRARED BACKGROUND POWER SPECTRUM

    Energy Technology Data Exchange (ETDEWEB)

    Thacker, Cameron; Cooray, Asantha; Smidt, Joseph; De Bernardis, Francesco; Mitchell-Wynne, K. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Amblard, A. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Auld, R.; Eales, S.; Pascale, E. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff, CF24 3AA (United Kingdom); Baes, M.; Michalowski, M. J. [Sterrenkundig Observatorium, Universiteit Gent, KrijgslAAn 281 S9, B-9000 Gent (Belgium); Clements, D. L.; Dariush, A.; Hopwood, R. [Physics Department, Imperial College London, South Kensington campus, London, SW7 2AZ (United Kingdom); De Zotti, G. [INAF, Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, I-35122 Padova (Italy); Dunne, L.; Maddox, S. [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Hoyos, C. [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Ibar, E. [UK Astronomy Technology Centre, The Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom); Jarvis, M. [Astrophysics, Department of Physics, Keble Road, Oxford, OX1 3RH (United Kingdom); and others

    2013-05-01

    We present a measurement of the angular power spectrum of the cosmic far-infrared background (CFIRB) anisotropies in one of the extragalactic fields of the Herschel Astrophysical Terahertz Large Area Survey at 250, 350, and 500 {mu}m bands. Consistent with recent measurements of the CFIRB power spectrum in Herschel-SPIRE maps, we confirm the existence of a clear one-halo term of galaxy clustering on arcminute angular scales with large-scale two-halo term of clustering at 30 arcmin to angular scales of a few degrees. The power spectrum at the largest angular scales, especially at 250 {mu}m, is contaminated by the Galactic cirrus. The angular power spectrum is modeled using a conditional luminosity function approach to describe the spatial distribution of unresolved galaxies that make up the bulk of the CFIRB. Integrating over the dusty galaxy population responsible for the background anisotropies, we find that the cosmic abundance of dust, relative to the critical density, to be between {Omega}{sub dust} = 10{sup -6} and 8 Multiplication-Sign 10{sup -6} in the redshift range z {approx} 0-3. This dust abundance is consistent with estimates of the dust content in the universe using quasar reddening and magnification measurements in the Sloan Digital Sky Survey.

  12. Prospects for Studying Interstellar Magnetic Fields with a Far-Infrared Polarimeter for SAFIR

    Science.gov (United States)

    Dowell, C. Darren; Chuss, D. T.; Dotson, J. L.

    2008-01-01

    Polarimetry at mid-infrared through millimeter wavelengths using airborne and ground-based telescopes has revealed magnetic structures in dense molecular clouds in the interstellar medium, primarily in regions of star formation. Furthermore, spectropolarimetry has offered clues about the composition of the dust grains and the mechanism by which they are aligned with respect to the local magnetic field. The sensitivity of the observations to date has been limited by the emission from the atmosphere and warm telescopes. A factor of 1000 in sensitivity can be gained by using instead a cold space telescope. With 5 arcminute resolution, Planck will make the first submillimeter polarization survey of the full Galaxy early in the next decade. We discuss the science case for and basic design of a far-infrared polarimeter on the SAFIR space telescope, which offers resolution in the few arcsecond range and wavelength selection of cold and warm dust components. Key science themes include the formation and evolution of molecular clouds in nearby spiral galaxies, the magnetic structure of the Galactic center, and interstellar turbulence.

  13. Fundamental Limits on the Imaging and Polarisation Properties of Far-Infrared Detectors

    Science.gov (United States)

    Thomas, Christopher N.; Withington, Stafford; Chuss, David T.; Wollack, Edward J.; Moseley, S. Harvey

    2009-01-01

    Far-infrared bolometric detectors are used extensively in ground-based and space-borne astronomy, and thus it is important to understand their optical behaviour precisely. We have studied the intensity and polarisation response of free-space bolometers, and shown that when the size of the absorber is reduced below a wavelength, the response changes from being that of a classical optical detector to that of a few-mode antenna. We have calculated the modal content of the reception patterns, and found that for any volumetric detector having a side length of less than a wavelength, three magnetic and three electric dipoles characterize the behaviour. The size of the absorber merely determines the relative strengths of the contributions. The same formalism can be applied to thin-film absorbers, where the induced current is forced to flow in a plane. In this case, one magnetic and two electric dipoles characterize the behaviour. The ability to model easily the intensity, polarisation, and straylight characteristics of electrically-small detectors will be of great value when designing high-performance polarimetric imaging arrays.

  14. GaAs Blocked-Impurity-Band Detectors for Far-Infrared Astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Cardozo, Benjamin Lewin [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    High-purity and doped GaAs films have been grown by Liquid-phase epitaxy (LPE) for development of a blocked impurity band (BIB) detector for far-infrared radiation. The film growth process developed has resulted in the capability to grow GaAs with a net active impurity concentration below 1 x 1013 cm-3, ideal for the blocking layer of the BIB detector. The growth of n-type LPE GaAs films with donor concentrations below the metal-insulator transition, as required for the absorbing layer of a BIB detector, has been achieved. The control of the donor concentration, however, was found to be insufficient for detector production. The growth by LPE of a high-purity film onto a commercially grown vapor-phase epitaxial (VPE) n-type GaAs doped absorbing layer resulted in a BIB device that showed a significant reduction in the low-temperature dark current compared to the absorbing layer only. Extended optical response was not detected, most likely due to the high compensation of the commercially grown GaAs absorbing layer, which restricts the depletion width of the device.

  15. Far-infrared observations of an unbiased sample of gamma-ray burst host galaxies

    CERN Document Server

    Kohn, Saul A; Bourne, Nathan; Baes, Maarten; Fritz, Jacopo; Cooray, Asantha; De Looze, Ilse; De Zotti, Gianfranco; Dannerbauer, Helmut; Dunne, Loretta; Dye, Simon; Eales, Stephen; Furlanetto, Cristina; Gonzalez-Nuevo, Joaquin; Ibar, Edo; Ivison, Rob J; Maddox, Steve J; Scott, Douglas; Smith, Daniel J B; Smith, Matthew W L; Symeonidis, Myrto; Valiante, Elisabetta

    2015-01-01

    Gamma-ray bursts (GRBs) are the most energetic phenomena in the Universe; believed to result from the collapse and subsequent explosion of massive stars. Even though it has profound consequences for our understanding of their nature and selection biases, little is known about the dust properties of the galaxies hosting GRBs. We present analysis of the far-infrared properties of an unbiased sample of 21 GRB host galaxies (at an average redshift of $z\\,=\\,3.1$) located in the {\\it Herschel} Astrophysical Terahertz Large Area Survey (H-ATLAS), the {\\it Herschel} Virgo Cluster Survey (HeViCS), the {\\it Herschel} Fornax Cluster Survey (HeFoCS), the {\\it Herschel} Stripe 82 Survey (HerS) and the {\\it Herschel} Multi-tiered Extragalactic Survey (HerMES), totalling $880$ deg$^2$, or $\\sim 3$\\% of the sky in total. Our sample selection is serendipitous, based only on whether the X-ray position of a GRB lies within a large-scale {\\it Herschel} survey -- therefore our sample can be considered completely unbiased. Using ...

  16. Recognizing pedestrian's unsafe behaviors in far-infrared imagery at night

    Science.gov (United States)

    Lee, Eun Ju; Ko, Byoung Chul; Nam, Jae-Yeal

    2016-05-01

    Pedestrian behavior recognition is important work for early accident prevention in advanced driver assistance system (ADAS). In particular, because most pedestrian-vehicle crashes are occurred from late of night to early of dawn, our study focus on recognizing unsafe behavior of pedestrians using thermal image captured from moving vehicle at night. For recognizing unsafe behavior, this study uses convolutional neural network (CNN) which shows high quality of recognition performance. However, because traditional CNN requires the very expensive training time and memory, we design the light CNN consisted of two convolutional layers and two subsampling layers for real-time processing of vehicle applications. In addition, we combine light CNN with boosted random forest (Boosted RF) classifier so that the output of CNN is not fully connected with the classifier but randomly connected with Boosted random forest. We named this CNN as randomly connected CNN (RC-CNN). The proposed method was successfully applied to the pedestrian unsafe behavior (PUB) dataset captured from far-infrared camera at night and its behavior recognition accuracy is confirmed to be higher than that of some algorithms related to CNNs, with a shorter processing time.

  17. Atrazine Molecular Imprinted Polymers: Comparative Analysis by Far-Infrared and Ultraviolet Induced Polymerization

    Science.gov (United States)

    Chen, Jun; Bai, Lian-Yang; Liu, Kun-Feng; Liu, Run-Qiang; Zhang, Yu-Ping

    2014-01-01

    Atrazine molecular imprinted polymers (MIPs) were comparatively synthesized using identical polymer formulation by far-infrared (FIR) radiation and ultraviolet (UV)-induced polymerization, respectively. Equilibrium binding experiments were carried out with the prepared MIPs; the results showed that MIPuv possessed specific binding to atrazine compared with their MIPFIR radiation counterparts. Scatchard plot’s of both MIPs indicated that the affinities of the binding sites in MIPs are heterogeneous and can be approximated by two dissociation-constants corresponding to the high-and low-affinity binding sites. Moreover, several common pesticides including atrazine, cyromazine, metamitron, simazine, ametryn, terbutryn were tested to determine their specificity, similar imprinting factor (IF) and different selectivity index (SI) for both MIPs. Physical characterization of the polymers revealed that the different polymerization methods led to slight differences in polymer structures and performance by scanning electron microscope (SEM), Fourier transform infrared absorption (FT-IR), and mercury analyzer (MA). Finally, both MIPs were used as selective sorbents for solid phase extraction (SPE) of atrazine from lake water, followed by high performance liquid chromatography (HPLC) analysis. Compared with commercial C18 SPE sorbent (86.4%–94.8%), higher recoveries of atrazine in spiked lake water were obtained in the range of 90.1%–97.1% and 94.4%–101.9%, for both MIPs, respectively. PMID:24398982

  18. Influence of Water Activated by Far infrared Porous Ceramics on Nitrogen Absorption in the Pig Feed.

    Science.gov (United States)

    Meng, Junping; Liu, Jie; Liang, Jinsheng; Zhang, Hongchen; Ding, Yan

    2016-04-01

    Under modern and, intensive feeding livestock and poultry density has increased, and brought a deterioration of the farm environment. The livestock and their excrement generate harmful gases such as ammonia, etc. which restricted the sustainable development and improvement of production efficiency of animal husbandry. In this paper, a new kind of far infrared porous ceramics was prepared to activate, the animal drinking water. The activated water and common water were then supplied to pigs, and the fresh pig feces of experimental group and:control group were collected on a regular basis. The residual protein content in feces was tested by Kjeldahl nitrogen method to study the influence law of the porous ceramics on absorbing nitrogen element in animal feces. The results showed that compared with the control group, the protein content in the experimental group decreased on average by 39.2%. The activated drinking water was conducive to the absorption of nitrogen in pig feed. The clusters of water molecules became smaller under the action of the porous ceramics. Hence, they were easy to pass through the water protein channel on the cell membrane for speeding up the metabolism.

  19. SEASONAL DISAPPEARANCE OF FAR-INFRARED HAZE IN TITAN'S STRATOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Jennings, Donald E.; Anderson, C. M.; Flasar, F. M.; Cottini, V. [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Samuelson, R. E.; Nixon, C. A.; Kunde, V. G.; Achterberg, R. K. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); De Kok, R. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Coustenis, A.; Vinatier, S. [LESIA, Observatoire de Paris-Meudon, 92195 Meudon Cedex (France); Calcutt, S. B., E-mail: donald.e.jennings@nasa.gov [Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

    2012-07-20

    A far-infrared emission band attributed to volatile or refractory haze in Titan's stratosphere has been decreasing in intensity since Cassini's arrival in 2004. The 220 cm{sup -1} feature, first seen by the Voyager Infrared Interferometer Spectrometer, has only been found in Titan's winter polar region. The emission peaks at about 140 km altitude near the winter stratospheric temperature minimum. Observations recorded over the period 2004-2012 by the Composite Infrared Spectrometer on Cassini show a decrease in the intensity of this feature by about a factor of four. Possible seasonal causes of this decline are an increase in photolytic destruction of source chemicals at high altitude, a lessening of condensation as solar heating increased, or a weakening of downwelling of vapors. As of early 2012, the 220 cm{sup -1} haze has not yet been detected in the south. The haze composition is unknown, but its decrease is similar to that of HC{sub 3}N gas in Titan's polar stratosphere, pointing to a nitrile origin.

  20. Application of far-infrared irradiation in the manufacturing process of green tea.

    Science.gov (United States)

    Kim, So-Young; Jeong, Seok-Moon; Jo, Seong-Chun; Lee, Seung-Cheol

    2006-12-27

    Seven kinds of green tea leaves were manufactured with far-infrared (FIR) irradiation, and the physicochemical characteristics of the green tea were determined. Appropriate FIR irradiation during the manufacturing process significantly increased the polyphenolic content of green tea. FIR irradiation at 90 degrees C for 10 min, replacing the roasting step, and of the fully processed green tea leaves (GTP3) increased the total phenol content of green tea from 475.6 to 811.1 mg/g and the total flavanol content from 175.7 to 208.7 mg/g, as compared to the control. Epigallocatechin and epigallocatechin gallate increased from 57.68 and 9.60 mg/g in a nonirradiated control to 89.88 and 16.33 mg/g in GTP3, respectively. Ascorbic acid, caffeine, and nitrite scavenging activities were also increased in GTP3. However, the overall color change of GTP3 was negligible. These results indicate that the chemical properties of green tea are significantly affected by FIR irradiation at specific stages of the manufacturing process of green tea leaves and that this FIR irradiation results in high-quality green tea.

  1. The cosmic infrared background resolved by Spitzer - Contributions of mid-infrared galaxies to the far-infrared background

    NARCIS (Netherlands)

    Dole, H; Lagache, G; Puget, JL; Caputi, KI; Fernandez-Conde, N; Le Floc'h, E; Papovich, C; Perez-Gonzalez, PG; Rieke, GH; Blaylock, M

    Aims. We quantify the contributions of 24 mu m galaxies to the Far-Infrared ( FIR) Background at 70 and 160 mu m. We provide new estimates of the Cosmic Infrared Background ( CIB), and compare it with the Cosmic Optical Background ( COB). Methods. Using Spitzer data at 24, 70 and 160 mu m in three

  2. Thermal imaging method to visualize a hidden painting thermally excited by far infrared radiations

    Science.gov (United States)

    Davin, T.; Wang, X.; Chabane, A.; Pawelko, R.; Guida, G.; Serio, B.; Hervé, P.

    2015-06-01

    The diagnosis of hidden painting is a major issue for cultural heritage. In this paper, a non-destructive active infrared thermographic technique was considered to reveal paintings covered by a lime layer. An extended infrared spectral range radiation was used as the excitation source. The external long wave infrared energy source delivered to the surface is then propagated through the material until it encounters a painting zone. Due to several thermal effects, the sample surface then presents non-uniformity patterns. Using a high sensitive infrared camera, the presence of covered pigments can thus be highlighted by the analysis of the non-stationary phenomena. Reconstituted thermal contrast images of mural samples covered by a lime layer are shown.

  3. Metallicity and the spectral energy distribution and spectral types of dwarf O-stars

    NARCIS (Netherlands)

    Mokiem, MR; Martin-Hernandez, NL; Lenorzer, A; de Koter, A; Tielens, AGGA

    2004-01-01

    We present a systematic study of the effect of metallicity on the stellar spectral energy distribution (SED) of 0 main sequence (dwarf) stars, focussing on the hydrogen and helium ionizing continua, and on the optical and near-IR lines used for spectral classification. The spectra are based on non-L

  4. Robust and fast pedestrian detection method for far-infrared automotive driving assistance systems

    Science.gov (United States)

    Liu, Qiong; Zhuang, Jiajun; Ma, Jun

    2013-09-01

    Despite considerable effort has been contributed to night-time pedestrian detection for automotive driving assistance systems recent years, robust and real-time pedestrian detection is by no means a trivial task and is still underway due to the moving cameras, uncontrolled outdoor environments, wide range of possible pedestrian presentations and the stringent performance criteria for automotive applications. This paper presents an alternative night-time pedestrian detection method using monocular far-infrared (FIR) camera, which includes two modules (regions of interest (ROIs) generation and pedestrian recognition) in a cascade fashion. Pixel-gradient oriented vertical projection is first proposed to estimate the vertical image stripes that might contain pedestrians, and then local thresholding image segmentation is adopted to generate ROIs more accurately within the estimated vertical stripes. A novel descriptor called PEWHOG (pyramid entropy weighted histograms of oriented gradients) is proposed to represent FIR pedestrians in recognition module. Specifically, PEWHOG is used to capture both the local object shape described by the entropy weighted distribution of oriented gradient histograms and its pyramid spatial layout. Then PEWHOG is fed to a three-branch structured classifier using support vector machines (SVM) with histogram intersection kernel (HIK). An off-line training procedure combining both the bootstrapping and early-stopping strategy is introduced to generate a more robust classifier by exploiting hard negative samples iteratively. Finally, multi-frame validation is utilized to suppress some transient false positives. Experimental results on FIR video sequences from various scenarios demonstrate that the presented method is effective and promising.

  5. J=1-0 HCN toward bright far-infrared sources in the outer Galaxy

    Science.gov (United States)

    Pirogov, L.

    1999-08-01

    Results of the J=1-0 HCN observations toward 34 bright far-infrared sources selected from the IRAS Point Source Catalog are reported. Together with 17 sources observed in this line earlier (Pirogov et al., 1996) they form a complete sample of the sources with flux densities S(100 mu m)>500 Jy and delta > 0degr in the outer Galaxy. The HCN data are compared with the HCO(+) , NH_3, CS and CO data taken from literature. Prominent correlations with nearly similar slopes of ~ 1 are revealed between line integrated intensities of the molecules known to be high density tracers (HCN, HCO(+) , NH_3 and CS). The correlations become higher after adding the data for dark clouds, small globules and cirrus cores implying similar excitation and formation mechanisms of the considered molecules. Collisional excitation in regions with different densities as well as different molecular abundances and velocity dispersions in different types of cores seem to be important in producing these correlations. The following relations hold on the average over ~ 3 orders of magnitude of integrated intensities: I(HCN)>~ I(HCO(+) ~ ) I(CS) > I(NH_3) where ammonia integrated intensities are several times lower than HCN ones. Correlations are also found between HCN and CO integrated intensities for the sample sources as well as between HCN line widths and those of other species. The HCN lines have the same widths as the HCO(+) ones and are larger than CS and especially NH_3 line widths. Weak correlations are found between HCN line widths and luminosities of IRAS sources as well as between HCN integrated intensities, IRAS flux densities at 100mu m and luminosities of IRAS sources divided by distance squared. The sources with most intense HCN lines have associated water masers and molecular outflows while the lack of associated maser and outflow implies weak or no HCN emission. In order to reproduce the anomalies of the J=1-0 HCN hyperfine structure (R12 factor.

  6. Far-infrared and dust properties of present-day galaxies in the EAGLE simulations

    Science.gov (United States)

    Camps, Peter; Trayford, James W.; Baes, Maarten; Theuns, Tom; Schaller, Matthieu; Schaye, Joop

    2016-10-01

    The Evolution and Assembly of GaLaxies and their Environments (EAGLE) cosmological simulations reproduce the observed galaxy stellar mass function and many galaxy properties. In this work, we study the dust-related properties of present-day EAGLE galaxies through mock observations in the far-infrared and submm wavelength ranges obtained with the 3D dust radiative transfer code SKIRT. To prepare an EAGLE galaxy for radiative transfer processing, we derive a diffuse dust distribution from the gas particles and we re-sample the star-forming gas particles and the youngest star particles into star-forming regions that are assigned dedicated emission templates. We select a set of redshift-zero EAGLE galaxies that matches the K-band luminosity distribution of the galaxies in the Herschel Reference Survey (HRS), a volume-limited sample of about 300 normal galaxies in the Local Universe. We find overall agreement of the EAGLE dust scaling relations with those observed in the HRS, such as the dust-to-stellar mass ratio versus stellar mass and versus NUV-r colour relations. A discrepancy in the f250/f350 versus f350/f500 submm colour-colour relation implies that part of the simulated dust is insufficiently heated, likely because of limitations in our sub-grid model for star-forming regions. We also investigate the effect of adjusting the metal-to-dust ratio and the covering factor of the photodissociation regions surrounding the star-forming cores. We are able to constrain the important dust-related parameters in our method, informing the calculation of dust attenuation for EAGLE galaxies in the UV and optical domain.

  7. Analysis of the microwave, terahertz, and far infrared spectra of monodeuterated methanol CH{sub 2}DOH up to J = 26, K = 11, and o{sub 1}

    Energy Technology Data Exchange (ETDEWEB)

    Coudert, L. H., E-mail: laurent.coudert@lisa.u-pec.fr [Laboratoire Inter-universitaire des Systèmes Atmosphériques, UMR 7583 du CNRS, Universités Paris Est Créteil et Paris Diderot, 61 Avenue du Général de Gaulle, 94010 Créteil Cedex (France); Zemouli, M. [Laboratoire d' Études Physico-Chimiques, Université Dr. T. Moulay de Saïda, Saïda 20000 (Algeria); Motiyenko, R. A.; Margulès, L. [Laboratoire de Physique des Lasers, Atomes et Molécules, UMR 8523 CNRS - Université Lille I, Bât. P5, 59655 Villeneuve d' Ascq Cedex (France); Klee, S. [Physikalisch-Chemisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany)

    2014-02-14

    The first theoretical approach aimed at accounting for the energy levels of a non-rigid molecule displaying asymmetric-top asymmetric-frame internal rotation is developed. It is applied to a line position analysis of the high-resolution spectrum of the non-rigid CH{sub 2}DOH molecule and allows us to carry out a global analysis of a data set consisting of already available data and of microwave and far infrared transitions measured in this work. The analysis is restricted to the three lowest lying torsional levels (e{sub 0}, e{sub 1}, and o{sub 1}), to K ⩽ 11, and to J ⩽ 26. For the 8211 fitted lines, the unitless standard deviation is 2.4 and 103 parameters are determined including kinetic energy, hindering potential, and distortion effects parameters.

  8. Measurements of downwelling far-infrared radiance during the RHUBC-II campaign at Cerro Toco, Chile and comparisons with line-by-line radiative transfer calculations

    Science.gov (United States)

    Mast, Jeffrey C.; Mlynczak, Martin G.; Cageao, Richard P.; Kratz, David P.; Latvakoski, Harri; Johnson, David G.; Turner, David D.; Mlawer, Eli J.

    2017-09-01

    Downwelling radiances at the Earth's surface measured by the Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument in an environment with integrated precipitable water (IPW) as low as 0.03 cm are compared with calculated spectra in the far-infrared and mid-infrared. FIRST (a Fourier transform spectrometer) was deployed from August through October 2009 at 5.38 km MSL on Cerro Toco, a mountain in the Atacama Desert of Chile. There FIRST took part in the Radiative Heating in Unexplored Bands Campaign Part 2 (RHUBC-II), the goal of which is the assessment of water vapor spectroscopy. Radiosonde water vapor and temperature vertical profiles are input into the Atmospheric and Environmental Research (AER) Line-by-Line Radiative Transfer Model (LBLRTM) to compute modeled radiances. The LBLRTM minus FIRST residual spectrum is calculated to assess agreement. Uncertainties (1-σ) in both the measured and modeled radiances are also determined. Measured and modeled radiances nearly all agree to within combined (total) uncertainties. Features exceeding uncertainties can be corrected into the combined uncertainty by increasing water vapor and model continuum absorption, however this may not be necessary due to 1-σ uncertainties (68% confidence). Furthermore, the uncertainty in the measurement-model residual is very large and no additional information on the adequacy of current water vapor spectral line or continuum absorption parameters may be derived. Similar future experiments in similarly cold and dry environments will require absolute accuracy of 0.1% of a 273 K blackbody in radiance and water vapor accuracy of ∼3% in the profile layers contributing to downwelling radiance at the surface.

  9. The radio spectral energy distribution of infrared-faint radio sources

    Science.gov (United States)

    Herzog, A.; Norris, R. P.; Middelberg, E.; Seymour, N.; Spitler, L. R.; Emonts, B. H. C.; Franzen, T. M. O.; Hunstead, R.; Intema, H. T.; Marvil, J.; Parker, Q. A.; Sirothia, S. K.; Hurley-Walker, N.; Bell, M.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Callingham, J. R.; Deshpande, A. A.; Dwarakanath, K. S.; For, B.-Q.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hindson, L.; Johnston-Hollitt, M.; Kapińska, A. D.; Kaplan, D. L.; Lenc, E.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Oberoi, D.; Offringa, A.; Ord, S. M.; Prabu, T.; Procopio, P.; Udaya Shankar, N.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Zheng, Q.; Bannister, K. W.; Chippendale, A. P.; Harvey-Smith, L.; Heywood, I.; Indermuehle, B.; Popping, A.; Sault, R. J.; Whiting, M. T.

    2016-10-01

    Context. Infrared-faint radio sources (IFRS) are a class of radio-loud (RL) active galactic nuclei (AGN) at high redshifts (z ≥ 1.7) that are characterised by their relative infrared faintness, resulting in enormous radio-to-infrared flux density ratios of up to several thousand. Aims: Because of their optical and infrared faintness, it is very challenging to study IFRS at these wavelengths. However, IFRS are relatively bright in the radio regime with 1.4 GHz flux densities of a few to a few tens of mJy. Therefore, the radio regime is the most promising wavelength regime in which to constrain their nature. We aim to test the hypothesis that IFRS are young AGN, particularly GHz peaked-spectrum (GPS) and compact steep-spectrum (CSS) sources that have a low frequency turnover. Methods: We use the rich radio data set available for the Australia Telescope Large Area Survey fields, covering the frequency range between 150 MHz and 34 GHz with up to 19 wavebands from different telescopes, and build radio spectral energy distributions (SEDs) for 34 IFRS. We then study the radio properties of this class of object with respect to turnover, spectral index, and behaviour towards higher frequencies. We also present the highest-frequency radio observations of an IFRS, observed with the Plateau de Bure Interferometer at 105 GHz, and model the multi-wavelength and radio-far-infrared SED of this source. Results: We find IFRS usually follow single power laws down to observed frequencies of around 150 MHz. Mostly, the radio SEDs are steep (α IFRS show statistically significantly steeper radio SEDs than the broader RL AGN population. Our analysis reveals that the fractions of GPS and CSS sources in the population of IFRS are consistent with the fractions in the broader RL AGN population. We find that at least % of IFRS contain young AGN, although the fraction might be significantly higher as suggested by the steep SEDs and the compact morphology of IFRS. The detailed multi

  10. Physical and chemical structure of the IC 63 nebula. 1: Millimeter and far-infrared observations

    Science.gov (United States)

    Jansen, David J.; Van Dishoeck, Ewine F.; Black, John H.

    1994-01-01

    We present results of a (sub)millimeter and far-infrared study of the reflection/emission nebula IC 63, located close to the BO.5p star gamma Cas. The source has been mapped in the (12)CO 2 - 1 and 3 - 2, (13)CO 2 - 1, and CS 2 - 1 lines and shows a small molecular cloud less than 1'x 2' in extent, which coincides with the brightest optical nebulosity and IRAS 100 micrometer emission. IC 63 is therefore an excellent example of a nearby (d approximately = 230 pc), edge-on photon-dominated region (PDR). Various other molecules have been observed at the peak position through their rotational transitions, in order to probe the physical parameters and to derive abundances. The measured CO, HCO(+) HCN, CS and H2CO line ratios suggest that the cloud is warm, T approximately = 50 K, and dense, n (H2) approximately = 5 x 10(exp 4)/cu cm. Excitation of molecules by electrons may play a significant role in this PDR. On the basis of these physical conditions, column densities have been determined from the observed line strengths. Several different methods are discussed to constrain the H2 column density, including the use of measured submillimeter continuum fluxes. The resulting abundances of species such as CN and CS are similar to those found in cold, dark clouds like TMC-1 and L134N. However, the abundances of other simple molecules such as HNC, HCO(+) and possibly C2H are lower by factors of at least three, probably because of the enhanced photodissociation rates at a distance of 1.3 pc from a B star. Surprisingly, only the abundance of the H2S molecule appears enhanced. More complex, volatile molecules such as CH3OH CH3CN and HNCO, and the sulfur-oxides SO and SO2 have not been found in this cloud. Limited observations of molecules in the reflection nebulea NGC 2023 are presented as well, and the resulting molecular abundances are compared with those found for IC 63.

  11. What produces the far-infrared/submm emission in the most luminous QSOs?

    CERN Document Server

    Symeonidis, Myrto

    2016-01-01

    The AGN. I examine the average spectral energy distributions (SEDs) of two samples of the most powerful, unobscured QSOs at 2

  12. Infrared, Fourier transform far infrared spectroscopy, and viscosimetry research of aqueous-glycol fluids with thickener reology properties

    Science.gov (United States)

    Melnikov, Vyacheslav; Komarova, Tatyana; Vatagin, Vladimir; Bronnikova, Alla; Usol'tseva, Nadezhda

    1997-03-01

    At the first time Fourier transform far infrared spectroscopy in sequences with infrared spectroscopy and viscosimetry was applied to research of new water soluble oil composition possessing higher antiwear resistance, and antirust properties than produced by industry ones. A new structure for these compounds like micelleformation or hexagonal mesogenes without optical anisotropy at 55 - 65 degrees Celsius and defined composition have been found. Obtained data are discussed on base of modern advantages in the field of intermolecular interaction.

  13. Far infrared laser polarimetry and far forward scattering diagnostics for the C-2 field reversed configuration plasmas.

    Science.gov (United States)

    Deng, B H; Kinley, J S; Knapp, K; Feng, P; Martinez, R; Weixel, C; Armstrong, S; Hayashi, R; Longman, A; Mendoza, R; Gota, H; Tuszewski, M

    2014-11-01

    A two-chord far infrared (FIR) laser polarimeter for high speed sub-degree Faraday rotation measurements in the C-2 field reversed configuration experiment is described. It is based on high power proprietary FIR lasers with line width of about 330 Hz. The exceptionally low intrinsic instrument phase error is characterized with figures of merit. Significant toroidal magnetic field with rich dynamics is observed. Simultaneously obtained density fluctuation spectra by far forward scattering are presented.

  14. Performance of the Imaging Fourier Transform Spectrometer with Photoconductive Detector Arrays: An Application for the AKARI Far-Infrared Instrument

    CERN Document Server

    Kawada, Mitsunobu; Murakami, Noriko; Matsuo, Hiroshi; Okada, Yoko; Yasuda, Akiko; Matsuura, Shuji; Shirahata, Mai; Doi, Yasuo; Kaneda, Hidehiro; Ootsubo, Takafumi; Nakagawa, Takao; Shibai, Hiroshi

    2008-01-01

    We have developed an imaging Fourier transform spectrometer (FTS) for space-based far-infrared astronomical observations. The FTS employs a newly developed photoconductive detector arrays with a capacitive trans-impedance amplifier, which makes the FTS a completely unique instrument. The FTS was installed as a function of the far-infrared instrument (FIS: Far-Infrared Surveyor) on the Japanese astronomical satellite, AKARI, which was launched on February 21, 2006 (UT) from the Uchinoura Space Center. The FIS-FTS had been operated for more than one year before liquid helium ran out on August 26, 2007. The FIS-FTS was operated nearly six hundreds times, which corresponds to more than one hundred hours of astronomical observations and almost the same amount of time for calibrations. As expected from laboratory measurements, the FIS-FTS performed well and has produced a large set of astronomical data for valuable objects. Meanwhile, it becomes clear that the detector transient effect is a considerable factor for ...

  15. An ALMA Survey of Submillimetre Galaxies in the Extended Chandra Deep Field South: The Far-Infrared Properties of SMGs

    CERN Document Server

    Swinbank, Mark; Smail, Ian; Harrison, Chris; Hodge, Jacqueline; Karim, Alex; Walter, Fabian; Alexander, Dave; Brandt, Niel; de Breuck, Carlos; da Cunha, Elizabete; Chapman, Scott; Coppin, Kristen; Danielson, Alice; Dannerbauer, Helmut; Decarli, Roberto; Greve, Thomas; Ivison, Rob; Knudsen, Kirsten; Lagos, Claudia; Schinnerer, Eva; Thomson, Alasdair; Wardlow, Julie; Weiss, Axel; van der Werf, Paul

    2014-01-01

    We exploit ALMA 870um (345GHz) observations of submillimetre sources in the Extended Chandra Deep Field South to investigate the far-infrared properties of high-redshift submillimetre galaxies (SMGs). Using the precisely located 870um ALMA positions of 99 SMGs, together with 24um and radio imaging of this field, we deblend the Herschel/SPIRE imaging of this region to extract their far-infrared fluxes and colours. The median photometric redshifts for ALMA LESS (ALESS) SMGs which are detected in at least two SPIRE bands increases with wavelength of the peak in their SEDs, with z=2.3+/-0.2, 2.5+/-0.3 and 3.5+/-0.5 for the 250, 350 and 500-um peakers respectively. We find that 34 ALESS SMGs do not have a >3-sigma counterpart at 250, 350 or 500-um. These galaxies have a median photometric redshift of z=3.3+/-0.5, which is higher than the full ALESS SMG sample; z=2.5+/-0.2. Using the photometric redshifts together with the 250-870um photometry, we estimate the far-infrared luminosities and characteristic dust tempe...

  16. Tracing the Far-Infrared Roles of AGN in Dusty Star-Forming Galaxies

    Science.gov (United States)

    Brown, Arianna; Nayyeri, Hooshang; Cooray, Asantha R.; Mitchell-Wynne, Ketron

    2017-01-01

    Active galactic nuclei (AGNs) are suggested to play an important role in quenching their host galaxy’s star formation rate (SFR) by heating up and/or consuming the cool gas necessary to create stars. This mechanism is theorized as a critical step in AGN evolutionary models. The efforts to study this effect suffer in part from low-number statistics at high x-ray luminosities (LXR > 1044 ergs/s) for AGNs at z≈1-3, and a lack of separately estimated SFRs for AGN in dusty, star-forming galaxies (DSFGs). In this work, we extend our analysis to build a more complete picture using the variety of available multi-wavelength data in the XBoötes region. The Chandra XBoötes Survey is a 5-ks X-ray survey of the 9.3 square degree Boötes Field of the NOAO Deep Wide-Field Survey, a survey imaged from the optical to the near-IR. We estimate AGN spectral energy distributions and SFRs for ~400 x-ray sources using available data in all four Spitzer IRAC bands, the Spitzer MIPS 24µm band, all five Herschel SPIRE and PACS bands, along with NEWFIRM optical bands. Preliminary results show an exponential correlation between x-ray luminosity and star formation. As a comparison, we will use a stacking technique for the ~500 x-ray sources that were not detected at submillimeter wavelengths, where sources are binned by x-ray luminosity. We will compare these two samples and expect to see a difference in slope. Using these techniques, we hope to place tighter constraints on the mean SFRs of high-luminosity AGNs inside DSFGs, and determine if x-ray luminosities are independent of average SFRs for our sample in the Boötes field.

  17. Phonons and hybrid modes in the high and low temperature far infrared dynamics of hexagonal TmMnO3.

    Science.gov (United States)

    Massa, Néstor E; del Campo, Leire; De Sousa Meneses, Domingos; Echegut, Patrick; Martínez-Lope, María Jesús; Alonso, José Antonio

    2014-07-01

    We report on temperature dependent TmMnO3 far infrared emissivity and reflectivity spectra from 1910 K to 4 K. At the highest temperature the number of infrared bands is lower than that predicted for centrosymmetric P63/mmc (D(4)(6h)) (Z = 2) space group due to high temperature anharmonicity and possible defect induced bitetrahedra misalignments. On cooling, at ~1600 ± 40 K, TmMnO3 goes from non-polar to an antiferroelectric-ferroelectric polar phase reaching the ferroelectric onset at ~700 K. Room temperature reflectivity is fitted using 19 oscillators and this number of phonons is maintained down to 4 K. A weak phonon anomaly in the band profile at 217 cm(-1) (4 K) suggests subtle Rare Earth magneto-electric couplings at ~TN and below. A low energy collective excitation is identified as a THz instability associated with room temperature eg electrons in a d-orbital fluctuating environment. It condenses into two modes that emerge pinned to the E-type antiferromagnetic order hardening simultaneously down to 4 K. They obey power laws with TN as the critical temperature and match known zone center magnons. The one peaking at 26 cm(-1), with critical exponent β=0.42 as for antiferromagnetic order in a hexagonal lattice, is dependent on the Rare Earth ion. The higher frequency companion at ~50 cm(-1), with β=0.25, splits at ~TN into two peaks. The weaker band of the two is assimilated to the upper branch of the gap opening in the transverse acoustical (TA) phonon branch crossing the magnetic dispersion found in YMnO3. (Petit et al 2007 Phys. Rev. Lett. 99 266604). The stronger second band at ~36 cm(-1) corresponds to the lower branch of the TA gap. We assign both excitations as zone center magneto-electric hybrid quasiparticles, concluding that in NdMnO3 perovskite the equivalent picture corresponds to an instability which may be driven by an external field to transform NdMnO3 into a multiferroic compound by perturbation enhancing the TA

  18. Development of Blocked-Impurity-Band-Type Ge Detectors Fabricated with the Surface-Activated Wafer Bonding Method for Far-Infrared Astronomy

    Science.gov (United States)

    Hanaoka, M.; Kaneda, H.; Oyabu, S.; Yamagishi, M.; Hattori, Y.; Ukai, S.; Shichi, K.; Wada, T.; Suzuki, T.; Watanabe, K.; Nagase, K.; Baba, S.; Kochi, C.

    2016-07-01

    We report the current status of the development of our new detectors for far-infrared (FIR) astronomy. We develop Blocked-Impurity-Band (BIB)-type Ge detectors to realize large-format compact arrays covering a wide FIR wavelength range up to 200 \\upmu m. We fabricated Ge junction devices of different physical parameters with a BIB-type structure, using the room temperature, surface-activated wafer bonding (SAB) method. We measured the absolute responsivity and the spectral response curve of each device at low temperatures, using an internal blackbody source in a cryostat and a Fourier transform spectrometer, respectively. The results show that the SAB Ge junction devices have significantly higher absolute responsivities and longer cut-off wavelengths of the spectral response than the conventional bulk Ge:Ga device. Based upon the results, we discuss the optimum parameters of SAB Ge junction devices for FIR detectors. We conclude that SAB Ge junction devices possess a promising applicability to next-generation FIR detectors covering wavelengths up to ˜ 200 \\upmu m with high responsivity. As a next step, we plan to fabricate a BIB-type Ge array device in combination with a low-power cryogenic readout integrated circuit.

  19. Far-infrared spectroscopy of CH3OD in highly excited torsional states and the atlas of the Fourier transform spectra in the range 200-350 cm(-1).

    Science.gov (United States)

    Mukhopadhyay, I; Mellau, G C; Klee, S

    2000-10-01

    The high resolution Fourier transform far-infrared (FIR) spectrum of the torsion rotation band of CH3OD has been analyzed for the highly excited torsion states (n > or = 2) in the vibrational ground state. The spectrum shows splitting of the lines due to strong torsional-rotational-vibrational interactions in the molecule. Assignments were possible for rotational sub-bands in the torsional state as high as n = 4 and for K values up to 8 and J values of up to approximately 30 in most cases, for all the symmetry species. For the third excited torsional state n = 3 assignments were possible to K = 10. The data were analyzed with the help of the energy expansion model, which has been proven very successful in methanol. The state dependent expansion parameters are presented. These molecular parameters were able to reproduce the observed wavenumbers almost to within experimental accuracy of 0.0002 cm(-1) for clean unblended lines. These expansion coefficients should prove valuable in the calculation of precise energy values for excited torsional states up to n = 4, which is way above the torsional barrier. The detailed high-resolution spectral atlas of CH3OD has been presented in the range 200-350 cm(-1). This atlas is an extension of our earlier atlas in the range 20-205 cm(-1). The availability of this atlas in the journal will be very valuable for spectroscopists and astrophysicists seeking information in the infrared (IR) region in the laboratory and in outer space.

  20. The source of multi spectral energy of solar energetic electron

    Energy Technology Data Exchange (ETDEWEB)

    Herdiwijaya, Dhani [Astronomy Division and Bosscha Observatory, Faculty Mathematics and Natural Sciences, Intitute Technology of Bandung, Ganesha 10, Bandung, Indonesia 40132 dhani@as.itb.ac.id (Indonesia)

    2015-04-16

    We study the solar energetic electron distribution obtained from ACE and GOES satellites which have different altitudes and electron spectral energy during the year 1997 to 2011. The electron spectral energies were 0.038–0.315 MeV from EPAM instrument onboard ACE satellite and >2 MeV from GOES satellite. We found that the low electron energy has no correlation with high energy. In spite of we have corrected to the altitude differences. It implied that they originated from time dependent events with different sources and physical processes at the solar atmosphere. The sources of multi spectral energetic electron were related to flare and CME phenomena. However, we also found that high energetic electron comes from coronal hole.

  1. Spectral kinetic energy transfer in turbulent premixed reacting flows.

    Science.gov (United States)

    Towery, C A Z; Poludnenko, A Y; Urzay, J; O'Brien, J; Ihme, M; Hamlington, P E

    2016-05-01

    Spectral kinetic energy transfer by advective processes in turbulent premixed reacting flows is examined using data from a direct numerical simulation of a statistically planar turbulent premixed flame. Two-dimensional turbulence kinetic-energy spectra conditioned on the planar-averaged reactant mass fraction are computed through the flame brush and variations in the spectra are connected to terms in the spectral kinetic energy transport equation. Conditional kinetic energy spectra show that turbulent small-scale motions are suppressed in the burnt combustion products, while the energy content of the mean flow increases. An analysis of spectral kinetic energy transfer further indicates that, contrary to the net down-scale transfer of energy found in the unburnt reactants, advective processes transfer energy from small to large scales in the flame brush close to the products. Triadic interactions calculated through the flame brush show that this net up-scale transfer of energy occurs primarily at spatial scales near the laminar flame thermal width. The present results thus indicate that advective processes in premixed reacting flows contribute to energy backscatter near the scale of the flame.

  2. Herschel GASPS spectral observations of T Tauri stars in Taurus. Unraveling far-infrared line emission from jets and discs

    Science.gov (United States)

    Alonso-Martínez, M.; Riviere-Marichalar, P.; Meeus, G.; Kamp, I.; Fang, M.; Podio, L.; Dent, W. R. F.; Eiroa, C.

    2017-07-01

    Context. At early stages of stellar evolution young stars show powerful jets and/or outflows that interact with protoplanetary discs and their surroundings. Despite the scarce knowledge about the interaction of jets and/or outflows with discs, spectroscopic studies based on Herschel and ISO data suggests that gas shocked by jets and/or outflows can be traced by far-IR (FIR) emission in certain sources. Aims: We want to provide a consistent catalogue of selected atomic ([OI] and [CII]) and molecular (CO, H2O, and OH) line fluxes observed in the FIR, separate and characterize the contribution from the jet and the disc to the observed line emission, and place the observations in an evolutionary picture. Methods: The atomic and molecular FIR (60-190 μm) line emission of protoplanetary discs around 76 T Tauri stars located in Taurus are analysed. The observations were carried out within the Herschel key programme Gas in Protoplanetary Systems (GASPS). The spectra were obtained with the Photodetector Array Camera and Spectrometer (PACS). The sample is first divided in outflow and non-outflow sources according to literature tabulations. With the aid of archival stellar/disc and jet/outflow tracers and model predictions (PDRs and shocks), correlations are explored to constrain the physical mechanisms behind the observed line emission. Results: Outflow sources exhibit brighter atomic and molecular emission lines and higher detection rates than non-outflow sources. The line detection fractions decrease with SED evolutionary status (from Class I to Class III). We find correlations between [OI] 63.18 μm and [OI] 6300 Å, o-H2O 78.74 μm, CO 144.78 μm, OH 79.12+79.18 μm, and the continuum flux at 24 μm. The atomic line ratios can be explain either by fast (Vshock > 50 km s-1) dissociative J-shocks at low densities (n 103 cm-3) occurring along the jet and/or PDR emission (G0 > 102, n 103-106 cm-3). To account for the [CII] absolute fluxes, PDR emission or UV irradiation of shocks is needed. In comparison, the molecular emission is more compact and the line ratios are better explained with slow (Vshock different components and study their evolution. The much higher detection rate of emission lines in outflow sources and the compatibility of line ratios with shock model predictions supports the idea of a dominant contribution from the jet/outflow to the line emission, in particular at earlier stages of the stellar evolution as the brightness of FIR lines depends in large part on the specific evolutionary stage. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  3. New insights on the thermal dust from the far-infrared to the centimeter

    CERN Document Server

    Dupac, X; Boudet, N; Giard, M; Lamarre, J M; Mény, C; Pajot, F; Ristorcelli, I

    2003-01-01

    We present a compilation of PRONAOS-based results concerning the temperature dependence of the dust submillimeter spectral index, including data from Galactic cirrus, star-forming regions, dust associated to a young stellar object, and a spiral galaxy. We observe large variations of the spectral index (from 0.8 to 2.4) in a wide range of temperatures (11 to 80 K). These spectral index variations follow a hyperbolic-shaped function of the temperature, high spectral indices (1.6-2.4) being observed in cold regions (11-20 K) while low indices (0.8-1.6) are observed in warm regions (35-80 K). Three distinct effects may play a role in this temperature dependence: one is that the grain sizes change in dense environments, another is that the chemical composition of the grains is not the same in different environments, a third one is that there is an intrinsic dependence of the dust spectral index on the temperature due to quantum processes. This last effect is backed up by laboratory measurements and could be the do...

  4. Herschel/PACS observations of young sources in Taurus: the far-infrared counterpart of optical jets

    Science.gov (United States)

    Podio, L.; Kamp, I.; Flower, D.; Howard, C.; Sandell, G.; Mora, A.; Aresu, G.; Brittain, S.; Dent, W. R. F.; Pinte, C.; White, G. J.

    2012-09-01

    Context. Observations of the atomic and molecular line emission associated with jets and outflows emitted by young stellar objects provide sensitive diagnostics of the excitation conditions, and can be used to trace the various evolutionary stages they pass through as they evolve to become main sequence stars. Aims: To understand the relevance of atomic and molecular cooling in shocks, and how accretion and ejection efficiency evolves with the evolutionary state of the sources, we will study the far-infrared counterparts of bright optical jets associated with Class I and II sources in Taurus (T Tau, DG Tau A, DG Tau B, FS Tau A+B, and RW Aur). Methods: We have analysed Herschel/PACS observations of a number of atomic ([O i]63 μm, 145 μm, [C ii]158 μm) and molecular (high-J CO, H2O, OH) lines, collected within the open time key project GASPS (PI: W. R. F. Dent). To constrain the origin of the detected lines we have compared the obtained FIR emission maps with the emission from optical-jets and millimetre-outflows, and the measured line fluxes and ratios with predictions from shock and disk models. Results: All of the targets are associated with extended emission in the atomic lines; in particular, the strong [O i] 63 μm emission is correlated with the direction of the optical jet/mm-outflow. The line ratios suggest that the atomic lines can be excited in fast dissociative J-shocks occurring along the jet. The molecular emission, on the contrary, originates from a compact region, that is spatially and spectrally unresolved, and lines from highly excited levels are detected (e.g., the o-H2O 818-707 line, and the CO J = 36-35 line). Disk models are unable to explain the brightness of the observed lines (CO and H2O line fluxes up to 10-15-6 × 10-16 W m-2). Slow C- or J-shocks with high pre-shock densities reproduce the observed H2O and high-J CO lines; however, the disk and/or UV-heated outflow cavities may contribute to the observed emission. Conclusions

  5. Spectral Energy Distributions of Quasars and AGN

    Science.gov (United States)

    Wilkes, B.

    2004-06-01

    Active Galactic Nuclei (AGN) are multiwavelength emitters. To have any hope of understanding them, or even to determine their energy output, we must observe them in multiple wavebands using many telescopes. I will review what we have learned from broad-band observations of relatively bright, low-redshift AGN over the past ˜ 15 years. AGN can be found at all wavelengths but each provides a different view of the intrinsic population, often with little overlap between samples selected in different wavebands. I look forward to the full view of the intrinsic population which we will obtain over the next few years with surveys using today's new, sensitive observatories. These surveys are already finding enough new and different AGN candidates to pose the question ``What IS an AGN?".

  6. Broad-Band Tunability of a Far-Infrared Free-Electron Laser

    NARCIS (Netherlands)

    Bakker, R. J.; van der Geer, C. A. J.; Jaroszynski, D. A.; van der Meer, A. F. G.; Oepts, D.; van Amersfoort, P. W.

    1993-01-01

    A unique property of the free-electron laser (FEL) is its capability to be tuned continuously over a wide spectral range. This is a major difference with all other high-power lasers. However, the tunability of first-generation FELs used to be quite poor (typically 10% or less), due to constraints im

  7. Broad-Band Tunability of a Far-Infrared Free-Electron Laser

    NARCIS (Netherlands)

    Bakker, R. J.; van der Geer, C. A. J.; Jaroszynski, D. A.; van der Meer, A. F. G.; Oepts, D.; van Amersfoort, P. W.

    1993-01-01

    A unique property of the free-electron laser (FEL) is its capability to be tuned continuously over a wide spectral range. This is a major difference with all other high-power lasers. However, the tunability of first-generation FELs used to be quite poor (typically 10% or less), due to constraints

  8. Far-infrared and sub-millimetre surveys of circumstellar discs

    Science.gov (United States)

    Phillips, N. M.

    2011-06-01

    Stars of all ages and evolutionary stages are seen to be surrounded by discs of material. During the formation of a stellar system the stars are orbited by a massive protoplanetary disc composed of interstellar gas and dust, in which planet formation occurs. Between 1 and 10 Myr the protoplanetary disc disperses, leaving behind the newly formed system of planets and smaller bodies. The remaining material which has not formed into planets is referred to as a debris disc. Even though the interstellar dust grains from the protoplanetary disc have long been removed from the system, debris discs can contain large quantities of dust due to collisions between larger bodies and cometary activity. Such dust can be detected by its thermal emission. This thesis focuses on observational studies at far-infrared and sub-millimetre wavelengths of debris discs and the late stages of protoplanetary disc evolution. An overview of surveys for debris discs performed to date is presented, highlighting the limitations and statistical biases. The motivation, design and sample selection for two large surveys for debris discs around nearby stars, with the Herschel space observatory and the SCUBA-2 sub-millimetre camera on the James Clerk Maxwell Telescope, are described. The combination of a uniform observational strategy, longer wavelengths than previous surveys, and a large, clearly chosen sample - unbiased by stellar properties - will allow robust statistical conclusions of how the incidence and properties of debris discs depend on system parameters such as stellar mass, age, metallicity, binarity, and the presence of planets. As a precursor to the Herschel and SCUBA-2 surveys, a volume-limited sample of 130 A type star systems was surveyed using observations at 24 and 70 μm from the Spitzer space telescope. Stellar photosphere fluxes at 24 and 70 μm, which were required to determine the presence of emission from dust, were predicted by fitting model flux distributions to optical and

  9. Effect of nano-sized cerium-zirconium oxide solid solution on far-infrared emission properties of tourmaline powders

    Science.gov (United States)

    Guo, Bin; Yang, Liqing; Hu, Weijie; Li, Wenlong; Wang, Haojing

    2015-10-01

    Far-infrared functional nanocomposites were prepared by the co-precipitation method using natural tourmaline (XY3Z6Si6O18(BO3)3V3W, where X is Na+, Ca2+, K+, or vacancy; Y is Mg2+, Fe2+, Mn2+, Al3+, Fe3+, Mn3+, Cr3+, Li+, or Ti4+; Z is Al3+, Mg2+, Cr3+, or V3+; V is O2-, OH-; and W is O2-, OH-, or F-) powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample, tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that tourmaline modified with Ce and Zr has a better far-infrared emission property than tourmaline modified with Ce alone. Through characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the mechanism for oxygen evolution during the heat process in the two composite materials was systematically studied. The XPS spectra show that Fe3+ ratio inside tourmaline modified with Ce alone can be raised by doping Zr. Moreover, it is showed that there is a higher Ce3+ ratio inside the tourmaline modified with Ce and Zr than tourmaline modified with Ce alone. In addition, XRD results indicate the formation of CeO2 and Ce1-xZrxO2 crystallites during the heat treatment and further TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce-Zr doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of Fe2+ to Fe3+ inside the tourmaline caused by the change in the catalyst redox properties of CeO2 brought about by doping with Zr4+. In all samples, tourmaline modified with 7.14 wt.% Ce and 1.86 wt.% Zr calcined at 800∘C for 5 h has the best far-infrared emission property with the maximum emissivity value of 98%.

  10. Far-Infrared Space Interferometers: Future Windows on Star and Planet Formation

    Science.gov (United States)

    Leisawitz, David

    2004-01-01

    Far-IR space interferometers will provide observational access to a spectral region containing many important cooling and diagnostic spectral lines and the bulk of the thermal emission from dust at angular scales critical to advancing our understanding of the star and planet formation process. We will describe concepts for the Space Infrared Interferometric Telescope (SPIRIT) and the Submillimeter Probe of the Evolution of Cosmic Structure (SPECS). Both of these candidate NASA missions are imaging and spectral Michelson interferometers operating in the wavelength range -40 - 800 microns. SPIRIT, which could be launched in a decade as a NASA Origins Probe, is built on a deployable boom and has a maximum baseline length of -30 - 50 m, yielding sub-arcsecond resolution in the far-IR. SPIRIT will thus provide far-IR/sub-mm measurements complementary to the near- and mid-IR measurements obtainable with the James Webb Space Telescope (JWST), and well matched to JWST observations in angular resolution. Ultimately SPECS, a NASA Vision Mission, will use formation flying to attain baseline lengths up to 1 km, and thus angular resolution comparable to that of the Hubble Space Telescope and the Atacama Large Millimeter Array. We will report preliminary results of the NASA-sponsored SPIRIT and SPECS mission studies, which are now underway.

  11. High-Energy Spectral Signatures in $\\gamma$-Ray Bursts

    CERN Document Server

    Baring, M G

    1999-01-01

    One of the principal results obtained by the EGRET experiment aboard the Compton Gamma-Ray Observatory (CGRO) was the detection of several Gamma-ray bursts (GRBs) above 100 MeV. The broad-band spectra obtained for these bursts gave no indication of any high energy spectral attenuation that might preclude detection of bursts by ground-based Cerenkov telescopes (ACTs), thus motivating several TeV observational programs. This paper explores the expectations for the spectral properties in the TeV and sub-TeV bands for bursts, in particular how attenuation of photons by pair creation internal to the source modifies the spectrum to produce distinctive spectral signatures. The energy of spectral breaks and the associated spectral indices provide valuable information that can constrain the bulk Lorentz factor of the GRB outflow at a given time. These characteristics define palpable observational goals for ACT programs, and strongly impact the observability of bursts in the TeV band.

  12. Short-wavelength, mid- and far-infrared intersubband absorption in nonpolar GaN/Al(Ga)N heterostructures

    Science.gov (United States)

    Lim, Caroline B.; Beeler, Mark; Ajay, Akhil; Lähnemann, Jonas; Bellet-Amalric, Edith; Bougerol, Catherine; Schörmann, Jörg; Eickhoff, Martin; Monroy, Eva

    2016-05-01

    This paper assesses nonpolar m-oriented GaN:Si/Al(Ga)N heterostructures grown on free-standing GaN for intersubband optoelectronics in the short-wavelength, mid- and far-infrared ranges. Characterization results are compared with reference c-plane samples and interpreted by correlation with self-consistent Schrödinger-Poisson calculations. In the near- and mid-infrared regions, we demonstrate m-GaN/Al(Ga)N multi-quantum-wells exhibiting room-temperature intersubband absorption tunable in the range of 1.5-5.8 µm (827-214 meV), the long wavelength limit being set by the second order of the Reststrahlen band in the GaN substrates. Extending the study to the far-infrared region, low-temperature intersubband transitions in the 1.5-9 THz range (6.3-37.4 meV) are observed in larger m-plane GaN/AlGaN multi-quantum-wells, covering most of the 7-10 THz band forbidden to GaAs-based technologies.

  13. Broadband tunability of a far-infrared free-electron laser

    Science.gov (United States)

    Bakker, R. J.; van der Geer, C. A. J.; Jaroszynski, D. A.; van der Meer, A. F. G.; Oepts, D.; van Amerstoort, P. W.

    1993-08-01

    Results obtained in operation of the long-wavelength free electron laser (FEL) of the FELIX facility are presented. These involve measurements of the spectral range covered (16-110 microns), the output power, and the influence of the cavity desynchronism. The free electron laser for infrared experiments (FELIX) uses an undulator with tunable field strength that enables a factor of 2 tunability of the radiation wavelength. Results show that the dependence of the small signal gain and output power on cavity length tuning and undulator strength can be estimated. The results are compared with numerical simulations.

  14. Visual Method for Spectral Energy Distribution Calculation of Blazars

    Indian Academy of Sciences (India)

    Y. Huang; J. H. Fan

    2014-09-01

    In this work, we propose to use `The Geometer’s Sketchpad’ to the fitting of a spectral energy distribution of blazar based on three effective spectral indices, RO, OX, and RX and the flux density in the radio band. It can make us to see the fitting in detail with both the peak frequency and peak luminosity given immediately. We used our method to those sources whose peak frequency and peak luminosity are given and found that our results are consistent with those given in the work of Sambruna et al. (1996).

  15. The Spectral Energy Distribution of Fermi bright blazars

    CERN Document Server

    Abdo, A A; Ajello, M; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cavazzuti, E; Cecchi, C; Celik, O; Charles, E; Chaty, S; Chekhtman, A; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Colafrancesco, S; Cominsky, L R; Conrad, J; Costamante, L; Cutini, S; Dermer, C D; de Angelis, A; de Palma, F; Digel, S W; Silva, E do Couto e; Drell, P S; Dubois, R; Dumora, D; Farnier, C; Favuzzi, C; Fegan, S J; Focke, W B; Fortin, P; Frailis, M; Fuhrmann, L; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giommi, P; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grove, J E; Guillemot, L; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Healey, S E; Horan, D; Hughes, R E; Itoh, R; Jackson, M S; Johannesson, G; Johnson, A S; Johnson, W N; Kadler, M; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Knodlseder, J; Kocian, M L; Kuss, M; Lande, J; Latronico, L; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Max-Moerbeck, W; Mazziotta, M N; McConville, W; McEnery, J E; Meurer, C; Michelson, P F

    2009-01-01

    (Abridged) We have conducted a detailed investigation of the broad-band spectral properties of the \\gamma-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi gamma-ray spectra with Swift, radio, infra-red, optical and other hard X-ray/gamma-ray data, collected within three months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous Spectral Energy Distributions (SED) for 48 LBAS blazars.The SED of these gamma-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual Log $\

  16. Measuring the Evolution of Stellar Populations And Gas Metallicity in Galaxies with Far-Infrared Space Spectroscopy

    Science.gov (United States)

    Stacey, Gordon

    We propose a study of the evolution of stellar populations and gas metallicities in about 80 nearby star forming galaxies based on mining the NASA data archives for observations of the [NIII] 57 µm, [OIII] 52 µm and/or 88 µm, [NII] 122 and [CII] 158 µm far-infrared (FIR) fine- structure lines and other archives for thermal radio continuum. These lines are powerful probes of both stellar populations and gas properties and our primary science derives from these tracers. For sources that show both signs of active galactic nuclei (AGN) and star formation, we will take advantage of the readily available NASA Spitzer IRS data base that includes mid-IR [NeII] 12.8 µm, [NeIII] 15.6 µm and [NeV] 14.3 µm, [OIV] 25.9 µm and PAH observations. These complementary data reveal the relative fractions of the FIR line emission that might arise from star formation and the narrow line regions (NLR) associated with an AGN, thereby providing a robust set of observations to compare with star formation models. Subsets of the FIR lines have been detected from hundreds of nearby galaxies. From both theoretical studies and the results of these pioneering observations we know that these lines can be powerful probes of stellar populations and star formation in galaxies. Here we plan to use various combinations of the lines to constrain (1) the age of the stellar populations (through lines that trace the hardness of the stellar radiation fields, hence stellar spectral type), (2) the degree of processing of the interstellar medium (through lines that trace growth of secondary to primary element abundances for example, the N/O ratio), (3) the efficiency of star formation (through growth in absolute abundances of N and O, the N/H and O/H ratios), and (4) the current day mass function of upper main sequence stars. Surprisingly, there has been no systematic study of the large sample of these line detections made with PACS on Herschel in order to truly assess and calibrate their diagnostic

  17. The far-infrared spectrum of the core of Sagittarius B2

    Science.gov (United States)

    Erickson, E. F.; Caroff, L. J.; Simpson, J. P.; Strecker, D. W.; Goorvitch, D.

    1977-01-01

    A Michelson interferometer aboard NASA's Kuiper Airborne Observatory has been used to measure the spectrum of Sgr B2 from 40 to 200 kaysers with 5-kayser resolution in a 1.4-arcmin beam. The measured spectrum is smooth and featureless with a broad maximum at about 85 kaysers. The data can be fitted analytically with a model corresponding to thermal emission by a uniform sla of dust filling the beam, with an average temperature of approximately 32 K, an optical depth at 100 microns of about 1.6, and a spectral index of the dust emissivity about 1.5. The absence of features implies either that the source is optically thick or that the emission spectrum of the individual grains is smooth in the passband. The possible physical significance of this model is discussed.

  18. Evidence for competition modes in a partially guided far-infrared free-electron laser

    Directory of Open Access Journals (Sweden)

    J.-M. Ortega

    2014-10-01

    Full Text Available The infrared free-electron laser (FEL offers a large tunability since the FEL gain remains high throughout the infrared spectral range, and the reflectivity of metal mirrors remains also close to unity. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator. A solution is to use this chamber as a waveguide by adapting the radius of curvature of the cavity mirrors to this regime. Then, as has been shown before, a minimum appears in the spectrum that can be produced by the FEL. We discuss the physical mechanism of this particular regime and compare it to experiments using vacuum chambers of different transverse sizes. A good agreement is found with results of simulations and with a simple analytical formula.

  19. The Spectral Energy Distribution of Fermi Bright Blazars

    Science.gov (United States)

    Abdo, A. A.; Ackermann, M.; Agudo, I.; Ajello, M.; Aller, H. D.; Aller, M. F.; Angelakis, E.; Arkharov, A. A.; Axelsson, M.; Bach, U.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B. M.; Bechtol, K.; Bellazzini, R.; Benitiez, E.; Berdyugin, A.; Gehrels, N.; Harding, A. K.; Hays, E.; Marshall, F.; Scargle, J. D.; Thompson, D. J.

    2010-01-01

    We have conducted a detailed investigation of the broadband spectral properties of the gamma-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi gamma-ray spectra with Swift, radio, infra-red, optical, and other hard X-ray /gamma-ray data, collected within 3 months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous spectral energy distributions (SED) for 48 LBAS blazars. The SED of these gamma-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual log v-log v Fv representation, the typical broadband spectral signatures normally attributed to a combination of low-energy synchrotron radiation followed by inverse Compton emission of one or more components. We have used these SED to characterize the peak intensity of both the low- and the high-energy components. The results have been used to derive empirical relationships that estimate the position of the two peaks from the broadband colors (i.e., the radio to optical, alpha(sub ro) , and optical to X-ray, alpha(sub ox), spectral slopes) and from the gamma-ray spectral index. Our data show that the synchrotron peak frequency (v(sup S) (sub peak)) is positioned between 10(exp 12.5) and 10(exp 14) Hz in broad-lined flat spectrum radio quasars (FSRQs) and between 10(exp 13) and 10(exp 17) Hz in featureless BL Lacertae objects. We find that the gamma-ray spectral slope is strongly correlated with the synchrotron peak energy and with the X-ray spectral index, as expected at first order in synchrotron-inverse Compton scenarios. However, simple homogeneous, one-zone, synchrotron self-Compton (SSC) models cannot explain most of our SED, especially in the case of FSRQs and low energy peaked (LBL) BL Lacs. More complex models involving external Compton radiation or multiple SSC components are required to reproduce the overall SED and the observed spectral variability. While more than

  20. The Spectral Energy Distribution of Fermi Bright Blazars

    Science.gov (United States)

    Abdo, A. A.; Ackermann, M.; Agudo, I.; Ajello, M.; Aller, H. D.; Aller, M. F.; Angelakis, E.; Arkharov, A. A.; Axelsson, M.; Bach, U.; hide

    2010-01-01

    We have conducted a detailed investigation of the broadband spectral properties of the gamma-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi gamma-ray spectra with Swift, radio, infra-red, optical, and other hard X-ray /gamma-ray data, collected within 3 months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous spectral energy distributions (SED) for 48 LBAS blazars. The SED of these gamma-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual log v-log v Fv representation, the typical broadband spectral signatures normally attributed to a combination of low-energy synchrotron radiation followed by inverse Compton emission of one or more components. We have used these SED to characterize the peak intensity of both the low- and the high-energy components. The results have been used to derive empirical relationships that estimate the position of the two peaks from the broadband colors (i.e., the radio to optical, alpha(sub ro) , and optical to X-ray, alpha(sub ox), spectral slopes) and from the gamma-ray spectral index. Our data show that the synchrotron peak frequency (v(sup S) (sub peak)) is positioned between 10(exp 12.5) and 10(exp 14) Hz in broad-lined flat spectrum radio quasars (FSRQs) and between 10(exp 13) and 10(exp 17) Hz in featureless BL Lacertae objects. We find that the gamma-ray spectral slope is strongly correlated with the synchrotron peak energy and with the X-ray spectral index, as expected at first order in synchrotron-inverse Compton scenarios. However, simple homogeneous, one-zone, synchrotron self-Compton (SSC) models cannot explain most of our SED, especially in the case of FSRQs and low energy peaked (LBL) BL Lacs. More complex models involving external Compton radiation or multiple SSC components are required to reproduce the overall SED and the observed spectral variability. While more than

  1. The Evolving Physical Processes In Interacting Galaxies Traced By Their Spectral Energy Distributions

    Science.gov (United States)

    Smith, Howard

    Mergers and interactions have profound effects on the evolution of galaxies and on the various physical processes associated with star formation and the fueling of active nuclei (AGN). There remains, however, an incomplete understanding of how interactions affect such processes or how important they are in controlling the appearance of today's universe. We propose to study 180 interacting galaxies in 101 systems spanning early to late stage mergers for which newly archived NASA data enable detailed analyses of their ultraviolet-to-far infrared (UV-FIR) spectral energy distributions (SEDs). Our goal is an improved understanding of how a wide range of key galaxy parameters vary across the interaction sequence. Our derived physical parameters will include the total optical- infrared luminosity, star formation rate, specific star formation rate, stellar mass, dust temperatures and dust masses, compactness, photo-dissociation region (PDR) fractions, and AGN contributions to the FIR SED. Our sample is taken from the Keel-Kennicutt catalog of merging galaxies (based only on apparent galaxy separations and hence free of morphological bias) and the Surace IRAS sample of bright mergers. Our sample contains virtually all bright mergers with UV-FIR data in the archives, including (but not limited to) data from missions GALEX, Swift, Spitzer, WISE, and Herschel. We will re-reduce, recalibrate, and extract the photometry in up to 23 wavelength bands from the UV to the FIR. Our analysis plan emphasizes three new SED modeling tools, one of which we have recently developed. Nearly all of the sources also have Spitzer IRS spectral data (primarily of the circumnuclear regions), and we will use the IRS data to supplement the SED conclusions via our own algorithm which also infers metallicity, interstellar medium (ISM) ambient pressure, and embedded young star fractions. Finally, we will compare each merger to the simulated photometry/ morphology of a suite of simulations based on

  2. Asymmetric double quantum well structure as a tunable detector in the far-infrared range

    CERN Document Server

    Shin, U; Park, M J; Lee, S J

    1999-01-01

    The eigenvalues and the wave functions of GaAs/Al sub x Ga sub 1 sub - sub x As asymmetric double quantum well structure have been calculated by using of complex energy method. Based on theoretical calculations, tuning ranges from 9 to 14 mu m are predicted for the proposed asymmetric coupled-quantum-well structure. In addition we calculated the energy eigenvalues and the wave functions of an electron in GaAs/Al sub x Ga sub 1 sub - sub x As single quantum well structure (including delta-perturbation). the variation in E sub 1 , the ground state energy eigenvalue of the electron, depends on the strength and position of the perturbation within the well.

  3. Spectral light management for solar energy conversion systems

    Directory of Open Access Journals (Sweden)

    Stanley Cameron

    2016-06-01

    Full Text Available Due to the inherent broadband nature of the solar radiation, combined with the narrow spectral sensitivity range of direct solar to electricity devices, there is a massive opportunity to manipulate the solar spectrum to increase the functionality and efficiency of solar energy conversion devices. Spectral splitting or manipulation facilitates the efficient combination of both high-temperature solar thermal systems, which can absorb over the entire solar spectrum to create heat, and photovoltaic cells, which only convert a range of wavelengths to electricity. It has only recently been possible, with the development of nanofabrication techniques, to integrate micro- and nano-photonic structures as spectrum splitters/manipulators into solar energy conversion devices. In this paper, we summarize the recent developments in beam splitting techniques, and highlight some relevant applications including combined PV-thermal collectors and efficient algae production, and suggest paths for future development in this field.

  4. CMB spectral distortions and energy release in the early universe

    Science.gov (United States)

    Tashiro, Hiroyuki

    2014-06-01

    Measuring the spectral deviation of the cosmic microwave background (CMB) from the blackbody spectrum has become a focus of attention as a probe of the thermal history of the Universe. It has been more than 20 years since COBE/FIRAS's measurement, which showed excellent agreement between the CMB spectrum and a perfect blackbody spectrum. Significant developments in the technology since then have allowed us to improve the sensitivity of the absolute spectrum measurement by a factor of {˜ }10^4. Therefore, the physics related to the generation of CMB spectral distortions should now be investigated in greater detail. To probe the physics in the early universe and to open an observational window for new physics, various energy release mechanisms both in and beyond standard cosmology need to be studied. In this paper, we provide a review of the physics of CMB distortions and the energy release that creates CMB distortions in the early universe.

  5. Spectral light management for solar energy conversion systems

    Science.gov (United States)

    Stanley, Cameron; Mojiri, Ahmad; Rosengarten, Gary

    2016-06-01

    Due to the inherent broadband nature of the solar radiation, combined with the narrow spectral sensitivity range of direct solar to electricity devices, there is a massive opportunity to manipulate the solar spectrum to increase the functionality and efficiency of solar energy conversion devices. Spectral splitting or manipulation facilitates the efficient combination of both high-temperature solar thermal systems, which can absorb over the entire solar spectrum to create heat, and photovoltaic cells, which only convert a range of wavelengths to electricity. It has only recently been possible, with the development of nanofabrication techniques, to integrate micro- and nano-photonic structures as spectrum splitters/manipulators into solar energy conversion devices. In this paper, we summarize the recent developments in beam splitting techniques, and highlight some relevant applications including combined PV-thermal collectors and efficient algae production, and suggest paths for future development in this field.

  6. Improved ice particle optical property simulations in the ultraviolet to far-infrared regime

    Science.gov (United States)

    Bi, Lei; Yang, Ping

    2017-03-01

    To derive the bulk radiative properties of ice clouds, aircraft contrails and snow grains, which are fundamental to atmospheric radiative transfer calculations in downstream applications, it is necessary to accurately simulate the scattering of light by individual ice particles. An ice particle optical property database reported in 2013 (hereafter, TAMUice2013) is updated (hereafter, TAMUice2016) to incorporate recent advances in computation of the optical properties of nonspherical particles. Specifically, we employ the invariant imbedding T-matrix (II-TM) method to compute the optical properties of particles with small to moderate size parameters. Both versions use the Improved Geometric Optics Method (IGOM) to compute the optical properties of large ice crystals, but TAMUice2016 improves the treatment of inhomogeneous waves inside the scattering particles in the case where ice is absorptive such as at infrared wavelengths. To bridge the gap between the extinction efficiencies computed from the II-TM and the IGOM, TAMUice2016 includes spectrally dependent higher order terms of the edge effect in addition to the first order counterpart considered in TAMUice2013. Furthermore, the differences between TAMUice2013 and TAMUice2016 are quantified with respect to the computation of the bulk optical properties of ice clouds.

  7. Recent Advances in Laboratory Infrared Spectroscopy of Polycyclic Aromatic Hydrocarbons: PAHs in the Far Infrared

    Science.gov (United States)

    Mattioda, Andrew L.; Ricca, Alessandra; Tucker, Jonathan; Boersma, Christiaan; Bauschlicher, Charles, Jr.; Allamandola, Louis J.

    2010-01-01

    Over 25 years of observations and laboratory work have shown that the mid-IR spectra of a majority of astronomical sources are dominated by emission features near 3.3, 6.2, 7.7, and 11.2 microns, which originate in free polycyclic aromatic hydrocarbon (PAH) molecules. PAHs dominate the mid-IR emission from many galactic and extragalactic objects. As such, this material tracks a wide variety of astronomical processes, making this spectrum a powerful probe of the cosmos Apart from bands in the mid-IR, PAHs have bands spanning the Far-IR (FIR) and emission from these FIR features should be present in astronomical sources showing the Mid-IR PAH bands. However, with one exception, the FIR spectral characteristics are known only for a few neutral small PAHs trapped in salt pellets or oils at room temperature, data which is not relevant to astrophysics. Furthermore, since most emitting PAHs responsible for the mid-IR astronomical features are ionized, the absence of any experimental or theoretical PAH ion FIR spectra will make it impossible to correctly interpret the FIR data from these objects. In view of the upcoming Herschel space telescope mission and SOFIA's FIR airborne instrumentation, which will pioneer the FIR region, it is now urgent to obtain PAH FIR spectra. This talk will present an overview recent advances in the laboratory spectroscopy of PAHs, Highlighting the FIR spectroscopy along with some quantum calculations.

  8. Far Infrared Variability of Sagittarius A*: 25.5 Hours of Monitoring with $Herschel$

    CERN Document Server

    Stone, Jordan M; Dowell, C D; Schulz, B; Heinke, C O; Yusef-Zadeh, F

    2016-01-01

    Variable emission from Sgr~A*, the luminous counterpart to the super-massive black hole at the center of our Galaxy, arises from the innermost portions of the accretion flow. Better characterization of the variability is important for constraining models of the low-luminosity accretion mode powering Sgr~A*, and could further our ability to use variable emission as a probe of the strong gravitational potential in the vicinity of the $4\\times10^{6}\\mathrm{M}_{\\odot}$ black hole. We use the \\textit{Herschel} Spectral and Photometric Imaging Receiver (SPIRE) to monitor Sgr~A* at wavelengths that are difficult or impossible to observe from the ground. We find highly significant variations at 0.25, 0.35, and 0.5 mm, with temporal structure that is highly correlated across these wavelengths. While the variations correspond to $<$1% changes in the total intensity in the \\textit{Herschel} beam containing Sgr~A*, comparison to independent, simultaneous observations at 0.85 mm strongly supports the reality of the var...

  9. Spectral Gap Energy Transfer in Atmospheric Boundary Layer

    Science.gov (United States)

    Bhushan, S.; Walters, K.; Barros, A. P.; Nogueira, M.

    2012-12-01

    Experimental measurements of atmospheric turbulence energy spectra show E(k) ~ k-3 slopes at synoptic scales (~ 600 km - 2000 km) and k-5/3 slopes at the mesoscales (transfer, energy arrest at macroscales must be introduced. The most commonly used turbulence models developed to mimic the above energy transfer include the energy backscatter model for 2D turbulence in the horizontal plane via Large Eddy Simulation (LES) models, dissipative URANS models in the vertical plane, and Ekman friction for the energy arrest. One of the controversial issues surrounding the atmospheric turbulence spectra is the explanation of the generation of the 2D and 3D spectra and transition between them, for energy injection at the synoptic scales. Lilly (1989) proposed that the existence of 2D and 3D spectra can only be explained by the presence of an additional energy injection in the meso-scale region. A second issue is related to the observations of dual peak spectra with small variance in meso-scale, suggesting that the energy transfer occurs across a spectral gap (Van Der Hoven, 1957). Several studies have confirmed the spectral gap for the meso-scale circulations, and have suggested that they are enhanced by smaller scale vertical convection rather than by the synoptic scales. Further, the widely accepted energy arrest mechanism by boundary layer friction is closely related to the spectral gap transfer. This study proposes an energy transfer mechanism for atmospheric turbulence with synoptic scale injection, wherein the generation of 2D and 3D spectra is explained using spectral gap energy transfer. The existence of the spectral gap energy transfer is validated by performing LES for the interaction of large scale circulation with a wall, and studying the evolution of the energy spectra both near to and far from the wall. Simulations are also performed using the Advanced Weather and Research Forecasting (WRF-ARW) for moist zonal flow over Gaussian ridge, and the energy spectra close

  10. Diffuse X-ray scattering and far infrared absorption of barium and lead β" aluminas

    DEFF Research Database (Denmark)

    Hayes, W.; Kjær, Kristian; Pratt, F. L.;

    1985-01-01

    The authors have carried out high-momentum-resolution studies in diffuse X-ray scattering of barium and lead B" aluminas in the temperature range 20-700 degrees C. They have also measured the vibrational spectra of these compounds between 2K and 300K in the energy range 10-100 cm-1. The results a...

  11. Wave propagation of spectral energy content in a granular chain

    Science.gov (United States)

    Shrivastava, Rohit Kumar; Luding, Stefan

    2017-06-01

    A mechanical wave is propagation of vibration with transfer of energy and momentum. Understanding the spectral energy characteristics of a propagating wave through disordered granular media can assist in understanding the overall properties of wave propagation through inhomogeneous materials like soil. The study of these properties is aimed at modeling wave propagation for oil, mineral or gas exploration (seismic prospecting) or non-destructive testing of the internal structure of solids. The focus is on the total energy content of a pulse propagating through an idealized one-dimensional discrete particle system like a mass disordered granular chain, which allows understanding the energy attenuation due to disorder since it isolates the longitudinal P-wave from shear or rotational modes. It is observed from the signal that stronger disorder leads to faster attenuation of the signal. An ordered granular chain exhibits ballistic propagation of energy whereas, a disordered granular chain exhibits more diffusive like propagation, which eventually becomes localized at long time periods. For obtaining mean-field macroscopic/continuum properties, ensemble averaging has been used, however, such an ensemble averaged spectral energy response does not resolve multiple scattering, leading to loss of information, indicating the need for a different framework for micro-macro averaging.

  12. Wave propagation of spectral energy content in a granular chain

    Directory of Open Access Journals (Sweden)

    Shrivastava Rohit Kumar

    2017-01-01

    Full Text Available A mechanical wave is propagation of vibration with transfer of energy and momentum. Understanding the spectral energy characteristics of a propagating wave through disordered granular media can assist in understanding the overall properties of wave propagation through inhomogeneous materials like soil. The study of these properties is aimed at modeling wave propagation for oil, mineral or gas exploration (seismic prospecting or non-destructive testing of the internal structure of solids. The focus is on the total energy content of a pulse propagating through an idealized one-dimensional discrete particle system like a mass disordered granular chain, which allows understanding the energy attenuation due to disorder since it isolates the longitudinal P-wave from shear or rotational modes. It is observed from the signal that stronger disorder leads to faster attenuation of the signal. An ordered granular chain exhibits ballistic propagation of energy whereas, a disordered granular chain exhibits more diffusive like propagation, which eventually becomes localized at long time periods. For obtaining mean-field macroscopic/continuum properties, ensemble averaging has been used, however, such an ensemble averaged spectral energy response does not resolve multiple scattering, leading to loss of information, indicating the need for a different framework for micro-macro averaging.

  13. Far-infrared spectroscopy of star formation regions in M82

    Science.gov (United States)

    Duffy, P. B.; Erickson, E. F.; Haas, M. R.; Houck, J. R.

    1987-01-01

    Emission lines of (O III) at 52 microns and 88 microns and of (N III) at 57 microns in the nucleus of the galaxy M82 have been observed from the Kuiper Airborne Observatory with the facility's cooled grating spectrometer. The (N III) line has not been previously detected in any extragalactic source. The fluxes in the lines indicate approx. 4 x 10 to the 7th power M of ionized gas and a large population of massive stars (equivalent to 5 x 10 to the 5th power 08.5 stars), sufficient to power the infrared luminosity of the nucleus. We use the 52 to 88 micron line intensity ratio to find an average electron density of 210 + or - 75 in the nucleus; this is 10 to 100 times lower than values typically observed in individual compact H II regions in our Galaxy. The relative line strengths of the (O III) and (N III) lines imply an N(++)/O(++) ratio of 0.45 + or - 0.1, significantly lower than is measured by the same method in individual H II regions at similar galactocentric distances (equal to or less than 400 pc) in our Galaxy. This lower N(++)/O(++) ratio may be due to a lower N/O ratio, higher stellar temperatures, or both, in M82. At spectral resolutions of approx. 90 km/s, all three line profiles are similarly asymmetric. They can be well fitted by two Gaussian distributions with widths of approx. 150 km/s and central velocities of approx. 110 and approx. 295 km/s, bracketing the systemic velocity of the nucleus of approx. 210 km/s. Within uncertainties, both the N(++)/O(++) ratio and the electron density are the same for both Gaussian components; this indicates no major large-scale gradient in either quantity within the nucleus.

  14. Synchrotron radiation-based far-infrared spectroscopic ellipsometer with full Mueller-matrix capability.

    Science.gov (United States)

    Stanislavchuk, T N; Kang, T D; Rogers, P D; Standard, E C; Basistyy, R; Kotelyanskii, A M; Nita, G; Zhou, T; Carr, G L; Kotelyanskii, M; Sirenko, A A

    2013-02-01

    We developed far-IR spectroscopic ellipsometer at the U4IR beamline of the National Synchrotron Light Source in Brookhaven National Laboratory. This ellipsometer is able to measure both, rotating analyzer and full-Mueller matrix spectra using rotating retarders, and wire-grid linear polarizers. We utilize exceptional brightness of synchrotron radiation in the broad spectral range between about 20 and 4000 cm(-1). Fourier-transform infrared (FT-IR) spectrometer is used for multi-wavelength data acquisition. The sample stage has temperature variation between 4.2 and 450 K, wide range of θ-2θ angular rotation, χ tilt angle adjustment, and X-Y-Z translation. A LabVIEW-based software controls the motors, sample temperature, and FT-IR spectrometer and also allows to run fully automated experiments with pre-programmed measurement schedules. Data analysis is based on Berreman's 4 × 4 propagation matrix formalism to calculate the Mueller matrix parameters of anisotropic samples with magnetic permeability μ ≠ 1. A nonlinear regression of the rotating analyzer ellipsometry and∕or Mueller matrix (MM) spectra, which are usually acquired at variable angles of incidence and sample crystallographic orientations, allows extraction of dielectric constant and magnetic permeability tensors for bulk and thin-film samples. Applications of this ellipsometer setup for multiferroic and ferrimagnetic materials with μ ≠ 1 are illustrated with experimental results and simulations for TbMnO3 and Dy3Fe5O12 single crystals. We demonstrate how magnetic and electric dipoles, such as magnons and phonons, can be distinguished from a single MM measurement without adducing any modeling arguments. The parameters of magnetoelectric components of electromagnon excitations are determined using MM spectra of TbMnO3.

  15. Demonstration of Far-Infrared GaAs/A1GaAs Quantum Well Photodetectors for Broadband Wavelength Detection

    Institute of Scientific and Technical Information of China (English)

    SHEN Wen-Zhong; Perera A. G. U

    2000-01-01

    We discuss the realization of broadband wavelength detection by demonstrating the longest cutoff wavelength (λ,c = 28.6 μm) far-infrared GaAs/AIGaAs quantum well infrared photodetectors (QWIPs). The responsivity is comparable to that of mid-infrared GaAs/AIGaAs and InGaAs/GaAs QWIPs, with a responsivity of 0.265 A/W and detectivity of 3.4×109 cm. Hz1/2/W at the peak wavelength of 26.9μm at 4.2K. Based on the temperature dependent dark current and response results, it is expected that similar performance can be obtained at least up to 20 K. Several ways to expand the wavelength coverage are also addressed.

  16. Study of far-infrared reflection and Raman scattering spectra in reactive ion, etched ZnTe

    Institute of Scientific and Technical Information of China (English)

    吴森; 沈文忠; 小川博司; 郭其新

    2003-01-01

    Far-infrared reflection and Raman scattering measurements have been carried out on reactive ion,etched p-ZnTe samples.The averaged thickness of the surface damaged layer is found to be in the range of 1.0-1.5μm,and the,etch-induced defect density is in the order of 1018cm-3.The Raman intensity ratio between the second-order Raman peaks and the first-order longitudinal optical phonons reveals an increase trend with the radio frequency(rf)power.With the aid of related theories,we discuss the effects of the rf plasma power and the concentration of CH4/H2 on the damage,disorder,and the second-order Raman structures in p-ZnTe samples.

  17. HERschel Observations of Edge-on Spirals (HEROES). I: Far-infrared morphology and dust mass determination

    CERN Document Server

    Verstappen, J; Baes, M; Smith, M W L; Allaert, F; Bianchi, S; Blommaert, J A D L; De Geyter, G; De Looze, I; Gentile, G; Gordon, K D; Holwerda, B W; Viaene, S; Xilouris, E M

    2013-01-01

    Context. Edge-on spiral galaxies with prominent dust lanes provide us with an excellent opportunity to study the distribution and properties of the dust within them. The HEROES project was set up to observe a sample of seven large edge-on galaxies across various wavelengths for this investigation. Aims. Within this first paper, we present the Herschel observations and perform a qualitative and quantitative analysis on them, and we derive some global properties of the far infrared and submillimetre emission. Methods. We determine horizontal and vertical profiles from the Herschel observations of the galaxies in the sample and describe the morphology. Modified black-body fits to the global fluxes, measured using aperture photometry, result in dust temperatures and dust masses. The latter values are compared to those that are derived from radiative transfer models taken from the literature. Results. On the whole, our Herschel flux measurements agree well with archival values. We find that the exponential horizon...

  18. High sensitivity far infrared laser diagnostics for the C-2U advanced beam-driven field-reversed configuration plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Deng, B. H., E-mail: bdeng@trialphaenergy.com; Beall, M.; Schroeder, J.; Settles, G.; Feng, P.; Kinley, J. S.; Gota, H.; Thompson, M. C. [Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States)

    2016-11-15

    A high sensitivity multi-channel far infrared laser diagnostics with switchable interferometry and polarimetry operation modes for the advanced neutral beam-driven C-2U field-reversed configuration (FRC) plasmas is described. The interferometer achieved superior resolution of 1 × 10{sup 16} m{sup −2} at >1.5 MHz bandwidth, illustrated by measurement of small amplitude high frequency fluctuations. The polarimetry achieved 0.04° instrument resolution and 0.1° actual resolution in the challenging high density gradient environment with >0.5 MHz bandwidth, making it suitable for weak internal magnetic field measurements in the C-2U plasmas, where the maximum Faraday rotation angle is less than 1°. The polarimetry resolution data is analyzed, and high resolution Faraday rotation data in C-2U is presented together with direct evidences of field reversal in FRC magnetic structure obtained for the first time by a non-perturbative method.

  19. On the internal field correction in far-infrared absorption of highly polar molecules in neat liquids and dilute solutions

    Science.gov (United States)

    Vij, J. K.; Kalmykov, Yu P.

    1993-08-01

    Far-infrared absorption spectra for liquid acetone, methylene chloride, acetonitrile, methyl iodide, and their dilute solutions in cyclohexane at 20 °C are measured by molecular laser spectrometer. Measurements of dielectric loss of polar liquids and solutions in the frequency range 2-300 GHz are made using a number of different techniques. These two sets of measurements are combined with those made using a Fourier transform spectrometer in order to cover the frequency range up to 250 cm-1 and total integrated absorption intensities are calculated. It is shown that the discrepancy between experimental integrated absorption and the theoretical results given by Gordon's sum rule with the Polo-Wilson internal field factor can be explained in the context of Bossis' theory. This theory gives a better agreement with the experimental integrated absorption intensity for these liquids.

  20. High sensitivity far infrared laser diagnostics for the C-2U advanced beam-driven field-reversed configuration plasmas

    Science.gov (United States)

    Deng, B. H.; Beall, M.; Schroeder, J.; Settles, G.; Feng, P.; Kinley, J. S.; Gota, H.; Thompson, M. C.

    2016-11-01

    A high sensitivity multi-channel far infrared laser diagnostics with switchable interferometry and polarimetry operation modes for the advanced neutral beam-driven C-2U field-reversed configuration (FRC) plasmas is described. The interferometer achieved superior resolution of 1 × 1016 m-2 at >1.5 MHz bandwidth, illustrated by measurement of small amplitude high frequency fluctuations. The polarimetry achieved 0.04° instrument resolution and 0.1° actual resolution in the challenging high density gradient environment with >0.5 MHz bandwidth, making it suitable for weak internal magnetic field measurements in the C-2U plasmas, where the maximum Faraday rotation angle is less than 1°. The polarimetry resolution data is analyzed, and high resolution Faraday rotation data in C-2U is presented together with direct evidences of field reversal in FRC magnetic structure obtained for the first time by a non-perturbative method.

  1. Far-infrared optical conductivity gap in superconducting MgB2 films.

    Science.gov (United States)

    Kaindl, Robert A; Carnahan, Marc A; Orenstein, Joseph; Chemla, Daniel S; Christen, Hans M; Zhai, Hong-Ying; Paranthaman, Mariappan; Lowndes, Doug H

    2002-01-14

    We report the first study of the optical conductivity of MgB2 covering the range of its lowest-energy superconducting gap. Terahertz time-domain spectroscopy is utilized to determine the complex, frequency-dependent conductivity sigma(omega) of thin films. The imaginary part reveals an inductive response due to the emergence of the superconducting condensate. The real part exhibits a strong depletion of oscillator strength near 5 meV resulting from the opening of a superconducting energy gap. The gap ratio of 2Delta0/k(B)TC approximately 1.9 is well below the weak-coupling value, pointing to complex behavior in this novel superconductor.

  2. Contrast enhancement of mid and far infrared images of subcutaneous veins

    Science.gov (United States)

    Villaseñor-Mora, Carlos; Sanchez-Marin, Francisco J.; Garay-Sevilla, Maria E.

    2008-01-01

    A simple procedure to enhance the contrast of infrared images of subcutaneous veins is presented. This procedure implies the topical application of a substance which modifies the energy transfer process from the veins to the sensor of the infrared camera. After the application of the substance, energy is transferred in such a way that the image contrast is enhanced up to more than 400% of its original value. The duration of the effect spans for more than 11 min which is enough for many practical applications. This effect is shown through a series of infrared images of the hand, the foot and the neck of human subjects. The infrared spectra of the applied substance are presented to explain the related phenomena. The proposed procedure is innocuous, easy to achieve, time efficient, and of low cost.

  3. Novel InP- and GaSb-based light sources for the near to far infrared

    Science.gov (United States)

    Stephan, Sprengel; Frederic, Demmerle; Markus-Christian, Amann

    2016-11-01

    This topical review presents an overview on novel concepts for light emitting diodes (LEDs) and lasers for the near infrared to the THz regime. GaSb-based quantum well lasers are shown to be a promising concept for laser from the near to mid infrared. The GaSb-based edge-emitting lasers offer low thresholds for wavelengths ranging from about 2 to 3.7 μm. However, the development of vertical-cavity surface-emitting lasers and other advanced laser concepts is lagging behind due to material issues and complicated process technology. InP-based type-II quantum wells are an innovative concept for sources emitting in the wavelength range from 2 to 4 μm. This concept combines extended long wavelength emission with the reliable process technology of the already well-established InP-based lasers. Based on this, we present LEDs up to 3.5 μm wavelength, surface emitting lasers at 2.5 μm wavelength and edge emitting lasers up to 2.7 μm. For longer wavelengths, the so-called GaSb- and InAs-based interband cascade lasers can be used operating up to about 7 μm. The mid infrared range between 3 and 20 μm is also covered by quantum cascade lasers (QCL), which are dominating especially in the longer wavelength range above 7 μm. The far infrared reaching to the THz regime is exclusively covered by QCL. While for decades the only available semiconductor laser source for the far infrared and THz range was the direct THz QCL, recent progress demonstrated THz emission in nonlinear mid infrared QCLs. These devices are emitting THz by a nonlinear frequency conversion process, which allows operation at room temperature and beyond. Tunable THz lasers were demonstrated using both monolithic tuning mechanisms and an external cavity approach.

  4. The [CII]/[NII] far-infrared line ratio at z>5: extreme conditions for “normal” galaxies

    Science.gov (United States)

    Pavesi, Riccardo; Riechers, Dominik; Capak, Peter L.; Carilli, Chris Luke; Sharon, Chelsea E.; Stacey, Gordon J.; Karim, Alexander; Scoville, Nicholas; Smolcic, Vernesa

    2017-01-01

    Thanks to the Atacama Large (sub-)Millimeter Array (ALMA), observations of atomic far-infrared fine structure lines are a very productive way of measuring physical properties of the interstellar medium (ISM) in galaxies at high redshift, because they provide an unobscured view into the physical conditions of star formation. While the bright [CII] line has become a routine probe of the dynamical properties of the gas, its intensity needs to be compared to other lines in order to establish the physical origin of the emission. [NII] selectively traces the emission coming from the ionized fraction of the [CII]-emitting gas, offering insight into the phase structure of the ISM. Here we present ALMA measurements of [NII] 205 μm fine structure line emission from a representative sample of galaxies at z=5-6 spanning two orders of magnitude in star formation rate (SFR). Our results show at least two different regimes of ionized gas properties for galaxies in the first billion years of cosmic time, separated by their L[CII]/L[NII] ratio. First, we find extremely low [NII] emission compared to [CII] from a “typical” Lyman Break Galaxy (LBG-1), likely due to low dust content and reminiscent of local dwarfs. Second, the dusty Lyman Break Galaxy HZ10 and the extreme starburst AzTEC-3 show ionized gas fractions typical of local star-forming galaxies and show hints of spatial variations in their [CII]/[NII] line ratio. These observations of far-infrared lines in “normal” galaxies at z>5 yield some of the first constraints on ISM models for young galaxies in the first billion years of cosmic time and shed light on the observed evolution of the dust and gas properties.

  5. Terahertz time-domain spectroscopy response of amines and amino acids intercalated smectites in far-infrared region

    Energy Technology Data Exchange (ETDEWEB)

    Janek, M., E-mail: marian.janek@fns.uniba.sk [Comenius University, Faculty of Natural Sciences, Department of Physical and Theoretical Chemistry, Mlynská dolina CH1, SK-84215 Bratislava (Slovakia); Zich, D. [Comenius University, Faculty of Natural Sciences, Department of Physical and Theoretical Chemistry, Mlynská dolina CH1, SK-84215 Bratislava (Slovakia); Naftaly, M., E-mail: mira.naftaly@npl.co.uk [National Physical Laboratory, Hampton Rd, Teddington, Middlesex TW11 0LW (United Kingdom)

    2014-06-01

    Layered clay minerals from the smectite group with different chemical composition and resulting layer charge (e.g. pyrophyllite, illite, hectorite and montmorillonite) were characterised for their dielectric properties in the far-infrared region using terahertz-time domain spectroscopy (THz-TDS). Samples with distinct cation exchange capacity such as hectorite and montmorillonite were modified using cation exchange reaction with alkylamines or amino acids. The presence of these species in 2D gallery was proved by X-ray diffraction and Fourier transform infrared spectroscopy. The frequency-dependent refractive index of these minerals was determined in the experimentally accessible range of 0.1–3.0 THz (3–100 cm{sup −1}) using THz-TDS. Pristine samples revealed their refractive indices to be 1.82–2.15 at about 1 THz while the modified montmorillonite samples had their refractive indices changed by organic molecules used for their modification to 1.70–2.35 for amines and 1.97–2.36 for amino acids. The presence of organic substances in 2D gallery of clays was detectable despite the relatively high absorption of smectites with magnitude of 100 cm{sup −1}. - Graphical abstract: Display Omitted - Highlights: • “Guest” molecules in “host” layered material were investigated. • Amines and amino-acids were selected as guest molecules. • Natural and synthetic host with smectite phyllosilicate structure were used. • Dielectric properties were investigated by terahertz time domain spectroscopy. • Resonance absorption peaks of guest were detected in far infrared region.

  6. Intense ultrashort pulse generation using the JAERI far-infrared free electron laser

    CERN Document Server

    Nagai, R; Nishimori, N; Kikuzawa, N; Sawamura, M; Minehara, E J

    2002-01-01

    An intense ultrashort optical pulse has been quasi-continuously generated using a superconducting RF linac-based free-electron laser at a wavelength of 22.5 mu m. The pulse shape and width are measured by second-order optical autocorrelation with a birefringent Te crystal. At synchronism of the optical resonator, the pulse shape is a smooth single pulse with an FWHM width of 255 fs and energy of 74 mu J. A train of subpulses is developed by increasing the desynchronism of the optical resonator. The measured results are in good agreement with numerical simulation.

  7. Far-Infrared and Raman Spectroscopy Investigation of Phonon Modes in Amorphous and Crystalline Epitaxial GeTe-Sb2Te3 Alloys

    Science.gov (United States)

    Bragaglia, V.; Holldack, K.; Boschker, J. E.; Arciprete, F.; Zallo, E.; Flissikowski, T.; Calarco, R.

    2016-06-01

    A combination of far-infrared and Raman spectroscopy is employed to investigate vibrational modes and the carrier behavior in amorphous and crystalline ordered GeTe-Sb2Te3 alloys (GST) epitaxially grown on Si(111). The infrared active GST mode is not observed in the Raman spectra and vice versa, indication of the fact that inversion symmetry is preserved in the metastable cubic phase in accordance with the Fm3 space group. For the trigonal phase, instead, a partial symmetry break due to Ge/Sb mixed anion layers is observed. By studying the crystallization process upon annealing with both the techniques, we identify temperature regions corresponding to the occurrence of different phases as well as the transition from one phase to the next. Activation energies of 0.43 eV and 0.08 eV for the electron conduction are obtained for both cubic and trigonal phases, respectively. In addition a metal-insulator transition is clearly identified to occur at the onset of the transition between the disordered and the ordered cubic phase.

  8. Observations of the Hubble Deep Field with the Infrared Space Observatory; 5, Spectral Energy Distributions, Starburst Models and Star Formation History

    CERN Document Server

    Rowan-Robinson, M

    1997-01-01

    We have modelled the spectral energy distributions of the 13 HDF galaxies reliably detected by ISO. For 2 galaxies the emission detected by ISO is consistent with being starlight or the infrared 'cirrus' in the galaxies. For the remaining 11 galaxies there is a clear mid-infrared excess, which we interpret as emission from dust associated with a strong starburst. 10 of these galaxies are spirals or interacting pairs, while the remaining one is an elliptical with a prominent nucleus and broad emission lines. We give a new discussion of how the star formation rate can be deduced from the far infrared luminosity and derive star formation rates for these galaxies of 8-1000 $\\phi M_{\\sun}$ per yr, where $\\phi$ takes account of the uncertainty in the initial mass function. The HDF galaxies detected by ISO are clearly forming stars at a prodigious rate compared with nearby normal galaxies. We discuss the implications of our detections for the history of star and heavy element formation in the universe. Although unce...

  9. Ambipolar Diffusion and Far-Infrared Polarization from the Galactic Circumnuclear Disk

    CERN Document Server

    Desch, S J

    1996-01-01

    We describe an implicit prediction of the accretion disk models constructed by Wardle and Konigl (1990) for the circumnuclear disk (CND) of gas and dust near the Galactic center: supersonic ambipolar diffusion, an essential dynamical ingredient of the Wardle-Konigl disks, will cause the alignment of dust grains due to a process described by Roberge, Hanany, & Messinger (1995). We calculate synthetic maps of the polarized thermal emission which would be caused by ambipolar alignment in the preferred Wardle-Konigl model. Our maps are in reasonable agreement with 100 micron polarimetry of the CND if we assume that the grains have shapes similar to those of grains in nearby molecular clouds and that the CND contains a disordered magnetic field in energy equipartition with its ordered field.

  10. Advanced far infrared blocked impurity band detectors based on germanium liquid phase epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Christopher Sean [Univ. of California, Berkeley, CA (United States)

    1998-05-01

    This research has shown that epilayers with residual impurity concentrations of 5 x 1013 cm-3 can be grown by producing the purest Pb available in the world. These epilayers have extremely low minority acceptor concentrations, which is ideal for fabrication of IR absorbing layers. The Pb LPE growth of Ge also has the advantageous property of gettering Cu from the epilayer and the substrate. Epilayers have been grown with intentional Sb doping for IR absorption on lightly doped substrates. This research has proven that properly working Ge BIB detectors can be fabricated from the liquid phase as long as pure enough solvents are available. The detectors have responded at proper wavelengths when reversed biased even though the response did not quite reach minimum wavenumbers. Optimization of the Sb doping concentration should further decrease the photoionization energy of these detectors. Ge BIB detectors have been fabricated that respond to 60 cm-1 with low responsivity. Through reduction of the minority residual impurities, detector performance has reached responsivities of 1 A/W. These detectors have exhibited quantum efficiency and NEP values that rival conventional photoconductors and are expected to provide a much more sensitive tool for new scientific discoveries in a number of fields, including solid state studies, astronomy, and cosmology.

  11. Mid- to far infrared properties of star-forming galaxies and active galactic nuclei

    CERN Document Server

    Magdis, G E; Helou, G; Farrah, D; Hurley, P; Alonso-Herrero, A; Bock, J; Burgarella, D; Chapman, S; Charmandaris, V; Cooray, A; Dai, Y S; Dale, D; Elbaz, D; Feltre, A; Hatziminaoglou, E; Huang, J-S; Morrison, G; Oliver, S; Page, M; Scott, D; Shi, Y

    2013-01-01

    We study the mid- to far-IR properties of a 24um-selected flux-limited sample (S24 > 5mJy) of 154 intermediate redshift (~0.15), infrared luminous galaxies, drawn from the 5MUSES survey. By combining existing mid-IR spectroscopy and new Herschel SPIRE submm photometry from the HerMES program, we derived robust total infrared luminosity (LIR) and dust mass (Md) estimates and infered the relative contribution of the AGN to the infrared energy budget of the sources. We found that the total infrared emission of galaxies with weak 6.2um PAH emission (EW0.2um more than 50% of the LIR arises from star formation. We also found that for galaxies detected in the 250-500um Herschel bands an AGN has a statistically insignificant effect on the temperature of the cold dust and the far-IR colours of the host galaxy, which are primarily shaped by star formation activity. For star-forming galaxies we reveal an anti-correlation between the LIR-to-rest-frame 8um luminosity ratio, IR8 = LIR\\L8, and the strength of PAH features. ...

  12. High temperature far-infrared dynamics of orthorhombic NdMnO3: emissivity and reflectivity.

    Science.gov (United States)

    Massa, Néstor E; del Campo, Leire; Meneses, Domingos De Sousa; Echegut, Patrick; Martínez-Lope, María Jesús; Alonso, José Antonio

    2013-06-12

    We report on near normal far- and mid-infrared emission and reflectivity of NdMnO3 perovskite from room temperature to sample decomposition above 1800 K. At 300 K the number of infrared active phonons is in close agreement with the 25 calculated for the orthorhombic D(2h)(16)-Pbnm (Z = 4) space group. Their number gradually decreases as we approach the temperature of orbital disorder at ~1023 K where the orthorhombic O' lower temperature cooperative phase coexists with the cubic orthorhombic O. At above ~1200 K, the three infrared active phonons coincide with that expected for cubic Pm-3m (Z = 1) in the high temperature insulating regime. Heating samples in dry air triggers double exchange conductivity by Mn(3+) and Mn(4+) ions and a small polaron mid-infrared band. Fits to the optical conductivity single out the octahedral antisymmetric and symmetric vibrational modes as the main phonons in the electron-phonon interactions at 875 K. For 1745 K, it is enough to consider the symmetric stretching internal mode. An overdamped defect induced Drude component is clearly outlined at the highest temperatures. We conclude that rare earth manganite eg electrons are prone to spin, charge, orbital, and lattice couplings in an intrinsic orbital distorted perovskite lattice, favoring embryonic low energy collective excitations.

  13. A Far Infrared Polarimeter

    CERN Document Server

    Catalano, A

    2004-01-01

    We describe an experiment to measure calibration sources, the polarization of Cosmic Microwave Background Radiation (CMBR) and the polarization induced on the CMBR from S-Z effects, using a polarimeter, MITOPol, that will be employed at the MITO telescope. Two modulation methods are presented and compared: an amplitude modulation with a Fresnel double rhomb and a phase modulation with a modified Martin-Puplett interferometer. A first light is presented from the campaign (summer 2003) that has permitted to estimate the instrument spurious polarization using the second modulation method.

  14. The effect of leg hyperthermia using far infrared rays in bedridden subjects with type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Kawaura,Akihiko

    2010-04-01

    Full Text Available

    We examined the effect of leg hyperthermia on oxidative stress in bedridden subjects with type 2 diabetes mellitus using 15-min sessions of far infrared rays over a two-week period. Four subjects (male 1, female 3 incapacitated by a stroke were recruited for this study. All patients were admitted to Takahashi Central Hospital and ate the same hospital meals. Fasting plasma glucose, HbA1c, tumor necrosis factor (TNFalpha, free fatty acid, leptin, adiponectin and plasma 8-epi-prostaglandin F2alpha (8-epi-PGF2alpha levels as a marker of oxidative stress were measured on admission, just before and 2 weeks after local heating of the leg. Results showed that plasma total 8-epi-PGF2alpha levels were decreased significantly while TNFalpha levels were increased significantly. On the other hand, glucose, HbA1c, free fatty acid, leptin and adiponectin levels were not changed during the study period. These results suggest that repeated leg hyperthermia may protect against oxidative stress.

  15. Confirming the Quiescent Galaxy Population out to $z=3$: A Stacking Analysis of Mid-, Far-Infrared and Radio Data

    CERN Document Server

    Man, Allison W S; Toft, Sune; Magnelli, Benjamin; Karim, Alexander; Ilbert, Olivier; Salvato, Mara; Floc'h, Emeric Le; Bertoldi, Frank; Casey, Caitlin M; Lee, Nicholas; Li, Yanxia; Navarrete, Felipe; Sheth, Kartik; Smolcic, Vernesa; Sanders, David B; Schinnerer, Eva; Zirm, Andrew W

    2014-01-01

    We present stringent constraints on the average mid-, far-infrared and radio emissions of $\\sim$14200 quiescent galaxies (QGs), identified out to $z=3$ in the COSMOS field via their rest-frame NUV$-$r and r$-$J colors, and with stellar masses $M_{\\star}=10^{9.8-12.2} \\,M_{\\odot} $. Stacking in deep Spitzer (MIPS $24\\,\\mu$m), Herschel (PACS and SPIRE), and VLA (1.4 GHz) maps reveals extremely low dust-obscured star formation rates for QGs (SFR $ 2$), consistent with the low unobscured SFRs ($10\\times$ below those of star-forming galaxies (SFGs) within the $M_{\\star}$- and $z$-ranges considered. The stacked 1.4 GHz signals (S/N $> 5$) are, if attributed solely to star formation, in excess of the total (obscured plus unobscured) SFR limits, suggestive of a widespread presence of low-luminosity active galactic nuclei (AGN) among QGs. Our results reaffirm the existence of a significant population QGs out to $z = 3$, thus corroborating the need for powerful quenching mechanism(s) to terminate star formation in gala...

  16. Insights into gas heating and cooling in the disc of NGC 891 from Herschel far-infrared spectroscopy

    CERN Document Server

    Hughes, T M; Schirm, M R P; Parkin, T J; De Looze, I; Wilson, C D; Bendo, G J; Baes, M; Fritz, J; Boselli, A; Cooray, A; Cormier, D; Karczewski, O Ł; Lebouteiller, V; Lu, N; Madden, S C; Spinoglio, L; Viaene, S

    2014-01-01

    We present Herschel PACS and SPIRE spectroscopy of the most important far-infrared cooling lines in the nearby edge-on spiral galaxy, NGC 891: [CII] 158 $\\mu$m, [NII] 122, 205 $\\mu$m, [OI] 63, 145 $\\mu$m, and [OIII] 88 $\\mu$m. We find that the photoelectric heating efficiency of the gas, traced via the ([CII]+[OII]63)/$F_{\\mathrm{TIR}}$ ratio, varies from a mean of 3.5$\\times$10$^{-3}$ in the centre up to 8$\\times$10$^{-3}$ at increasing radial and vertical distances in the disc. A decrease in ([CII]+[OII]63)/$F_{\\mathrm{TIR}}$ but constant ([CII]+[OI]63)/$F_{\\mathrm{PAH}}$ with increasing FIR colour suggests that polycyclic aromatic hydrocarbons (PAHs) may become important for gas heating in the central regions. We compare the observed flux of the FIR cooling lines and total IR emission with the predicted flux from a PDR model to determine the gas density, surface temperature and the strength of the incident far-ultraviolet (FUV) radiation field, $G_{0}$. Resolving details on physical scales of ~0.6 kpc, a p...

  17. Investigating the Relation between CO (3-2) and Far Infrared Luminosities for Nearby Merging Galaxies Using ASTE

    CERN Document Server

    Michiyama, Tomonari; Nakanishi, Kouichiro; Ueda, Junko; Saito, Toshiki; Ando, Misaki; Kaneko, Hiroyuki; Yamashita, Takuji; Matsuda, Yuichi; Hatsukade, Bunyo; Kikuchi, Kenichi; Komugi, Shinya; Muto, Takayuki

    2016-01-01

    We present the new single dish CO (3-2) emission data obtained toward 19 early stage and 7 late stage nearby merging galaxies using the Atacama Submillimeter Telescope Experiment (ASTE). Combining with the single dish and interferometric data of galaxies observed in previous studies, we investigate the relation between the CO (3-2) luminosity (L'CO(3-2)) and the far Infrared luminosity (LFIR) in a sample of 29 early stage and 31 late stage merging galaxies, and 28 nearby isolated spiral galaxies. We find that normal isolated spiral galaxies and merging galaxies have different slopes (alpha) in the log L'CO(3-2) - log LFIR plane (alpha ~ 0.79 for spirals and ~ 1.12 for mergers). The large slope (alpha > 1) for merging galaxies can be interpreted as an evidence for increasing Star Formation Efficiency (SFE=LFIR/L'CO(3-2)) as a function of LFIR. Comparing our results with sub-kpc scale local star formation and global star-burst activity in the high-z Universe, we find deviations from the linear relationship in t...

  18. Regional variations in the dense gas heating and cooling in M51 from Herschel far-infrared spectroscopy

    CERN Document Server

    Parkin, T J; Schirm, M R P; Baes, M; Boquien, M; Boselli, A; Cooray, A; Cormier, D; Foyle, K; Karczewski, O L; Lebouteiller, V; de Looze, I; Madden, S C; Roussel, H; Sauvage, M; Spinoglio, L

    2013-01-01

    We present Herschel PACS and SPIRE spectroscopy of the most important far-infrared cooling lines in M51, [CII](158 \\mu m), [NII](122 & 205 \\mu m), [OI](63 and 145 \\mu m) and [OIII](88 \\mu m). We compare the observed flux of these lines with the predicted flux from a photon dominated region model to determine characteristics of the cold gas such as density, temperature and the far-ultraviolet radiation field, G_0, resolving details on physical scales of roughly 600 pc. We find an average [CII]/F_TIR of 4 x 10^{-3}, in agreement with previous studies of other galaxies. A pixel-by-pixel analysis of four distinct regions of M51 shows a radially decreasing trend in both the far-ultraviolet (FUV) radiation field, G_0 and the hydrogen density, n, peaking in the nucleus of the galaxy, then falling off out to the arm and interarm regions. We see for the first time that the FUV flux and gas density are similar in the differing environments of the arm and interarm regions, suggesting that the inherent physical prope...

  19. Herschel far-infrared observations of the Carina Nebula complex II: The embedded young stellar and protostellar population

    CERN Document Server

    Gaczkowski, Benjamin; Ratzka, Thorsten; Roccatagliata, Veronica; Ohlendorf, Henrike; Zinnecker, Hans

    2012-01-01

    The Carina Nebula represents one of the largest and most active star forming regions known in our Galaxy with numerous very massive stars.Our recently obtained Herschel PACS & SPIRE far-infrared maps cover the full area (about 8.7 deg^2) of the Carina Nebula complex and reveal the population of deeply embedded young stellar objects, most of which are not yet visible in the mid- or near-infrared.We study the properties of the 642 objects that are independently detected as point-like sources in at least two of the five Herschel bands.For those objects that can be identified with apparently single Spitzer counterparts, we use radiative transfer models to derive information about the basic stellar and circumstellar parameters.We find that about 75% of the Herschel-detected YSOs are Class 0 protostars.The luminosities of the Herschel-detected YSOs with SED fits are restricted to values of <=5400 Lsun, their masses (estimated from the radiative transfer modeling) range from about 1 Msun to 10 Msun.Taking the...

  20. Star Formation Rates in Resolved Galaxies: Calibrations with Near and Far Infrared Data for NGC5055 and NGC6946

    CERN Document Server

    Li, Yiming; Calzetti, Daniela; Wilson, Christine D; Kennicutt, Robert C; Murphy, Eric J; Brandl, Bernhard R; Draine, B T; Galametz, M; Johnson, B D; Armus, L; Gordon, K D; Croxall, K; Dale, D A; Engelbracht, C W; Groves, B; Hao, C -N; Helou, G; Hinz, J; Hunt, L K; Krause, O; Roussel, H; Sauvage, M; Smith, J D T

    2013-01-01

    We use the near--infrared Br\\gamma hydrogen recombination line as a reference star formation rate (SFR) indicator to test the validity and establish the calibration of the {\\it Herschel} PACS 70 \\mu m emission as a SFR tracer for sub--galactic regions in external galaxies. Br\\gamma offers the double advantage of directly tracing ionizing photons and of being relatively insensitive to the effects of dust attenuation. For our first experiment, we use archival CFHT Br\\gamma and Ks images of two nearby galaxies: NGC\\,5055 and NGC\\,6946, which are also part of the {\\it Herschel} program KINGFISH (Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel). We use the extinction corrected Br\\gamma emission to derive the SFR(70) calibration for H{\\sc ii} regions in these two galaxies. A comparison of the SFR(70) calibrations at different spatial scales, from 200 pc to the size of the whole galaxy, reveals that about 50% of the total 70\\mu m emission is due to dust heated by stellar populations that are unr...

  1. Antibacterial effect of citrus press-cakes dried by high speed and far-infrared radiation drying methods

    Science.gov (United States)

    Samarakoon, Kalpa; Senevirathne, Mahinda; Lee, Won-Woo; Kim, Young-Tae; Kim, Jae-Il; Oh, Myung-Cheol

    2012-01-01

    In this study, the antibacterial effect was evaluated to determine the benefits of high speed drying (HSD) and far-infrared radiation drying (FIR) compared to the freeze drying (FD) method. Citrus press-cakes (CPCs) are released as a by-product in the citrus processing industry. Previous studies have shown that the HSD and FIR drying methods are much more economical for drying time and mass drying than those of FD, even though FD is the most qualified drying method. The disk diffusion assay was conducted, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined with methanol extracts of the dried CPCs against 11 fish and five food-related pathogenic bacteria. The disk diffusion results indicated that the CPCs dried by HSD, FIR, and FD prevented growth of all tested bacteria almost identically. The MIC and MBC results showed a range from 0.5-8.0 mg/mL and 1.0-16.0 mg/mL respectively. Scanning electron microscopy indicated that the extracts changed the morphology of the bacteria cell wall, leading to destruction. These results suggest that CPCs dried by HSD and FIR showed strong antibacterial activity against pathogenic bacteria and are more useful drying methods than that of the classic FD method in CPCs utilization. PMID:22808341

  2. Upgrade of the L-Band Linac at ISIR, Osaka University for a Far-Infrared FEL

    CERN Document Server

    Kato, Ryukou; Kashiwagi, Shigeru; Suemine, Shoji; Yamamoto, Tamotsu

    2004-01-01

    We are developing the far-infrared free-electron laser (FEL) using the L-band electron linac at the Institute of Scientific and Industrial Research (ISIR), Osaka University. The first lasing of the FEL was obtained at wavelengths from 32 to 40 μm in 1994, and the wavelength region has been extended up to 150 μm. The linac was designed and constructed for producing the high-intensity single-bunch beam for pulse radiolysis, so that the filling time of the accelerating structure is 1.8 μs long and the maximum macropulse length of the electron beam is limited to 2 μs, though the duration of the RF pulse can be extended to 4 μs. As a result, the FEL could not reach power saturation because the number of amplification times was limited. Recently, the linac has been extensively remodeled to realize high operational stability and reproducibility for advanced studies in beam science and technology. Almost all the peripheral components are replaced with new ones. At this opportunity, ...

  3. Combined far infrared RAIRS and XPS studies of TiCl 4 adsorption and reaction on Mg films

    Science.gov (United States)

    Pilling, M. J.; Fonseca, A. Amieiro; Cousins, M. J.; Waugh, K. C.; Surman, M.; Gardner, P.

    2005-08-01

    In recent years there has been an increase in interest in the study of model Ziegler-Natta catalysts used for the polymerisation of ethene and propene. Particular attention has focused on catalysts consisting of TiCl 4 on activated MgCl 2 accompanied by a co-catalyst, usually triethylaluminium (AlEt 3). As part of a wider project on the characterisation of model Ziegler-Natta catalysts we have investigated the interaction of TiCl 4 with metallic Mg films grown on a Au surface using X-ray photoelectron spectroscopy (XPS) and far infrared reflection absorption infrared spectroscopy. Somewhat surprisingly, the infrared spectra show little variation as a function of exposure to TiCl 4. A very broad asymmetric vibrational band grows in with maximum intensity at 382 cm -1. Three prominent low frequency shoulders are observed at approximately 360, 320, and 260 cm -1. For monolayer coverages of Mg the main band at 382 cm -1 is narrower, less asymmetric and accompanied by a prominent shoulder at 398 cm -1, which increases with increasing exposure to TiCl 4. TiCl 4 exposure in the presence of 5 × 10 -8 Torr of ethyl benzoate results in a change in line shape with low frequency broadening and a small shift in the frequency of the band. These spectra are discussed in the light of the possible constituent species making up the surface layer.

  4. A spectroscopic study of M rate at C{sub 82} metallofullerenes: Raman, far-infrared, and neutron scattering results

    Energy Technology Data Exchange (ETDEWEB)

    Lebedkin, S.; Renker, B.; Rietschel, H. [Forschungszentrum Karlsruhe (Germany). INFP; Heid, R. [Max-Planck-Institut fuer Physik komplexer Systeme, D-01187 Dresden (Germany); Schober, H. [Institut Laue-Langevin, F-38042 Grenoble (France)

    1998-03-01

    Polycrystalline samples of M rate at C{sub 82} metallofullerenes have been studied at room temperature by Raman (for M=La, Y, Ce, Gd), far-infrared (FIR) (for M=La, Y, Ce), and inelastic neutron scattering (INS) (for M=La, Y) spectroscopy. Raman and FIR spectra suggest that these metallofullerenes have a common dominant, if not a single, structure of the C{sub 82} cage and a similar bonding of the encapsulated metal ion, i.e. the bonding is primarily electrostatic and the metal atoms are in the same oxidation state (+3). The metal ion vibrations are located around 160 and 50 cm{sup -1}. INS reveals no gap between internal vibrational and external vibrational and rotational modes in the range {proportional_to}50-200 cm{sup -1} as is typically observed for other fullerides and also predicted by our model calculations. Presumably this is due to strong intermolecular interactions between M rate at C{sub 82} units in the bulk sample. The studied metallofullerenes are air sensitive, and degradation in air could be followed by changes in the Raman spectra. (orig.) With 6 figs., 2 tabs., 47 refs.

  5. GOODS-Herschel: The far-infrared view of star formation in AGN host galaxies since z~3

    CERN Document Server

    Mullaney, J R; Daddi, E; Alexander, D M; Elbaz, D; Hickox, R C; Bournaud, F; Altieri, B; Aussel, H; Coia, D; Dannerbauer, H; Dasyra, K; Dickinson, M; Hwang, H S; Kartaltepe, J; Leiton, R; Magdis, G; Magnelli, B; Popesso, P; Valtchanov, I; Del Moro, A; Hanish, D J; Ivison, R J; Juneau, S; Lutz, D; Sargent, M T

    2011-01-01

    Using 100um and 160um fluxes from GOODS-Herschel - the deepest survey undertaken by the Herschel telescope - we explore the infrared properties of X-ray AGNs up to z~3. The observed 100um and 160um fluxes are dominated by the host galaxy in the vast majority of cases (>94 per cent), meaning that these far-infrared fluxes provide an uncontaminated view of the star formation in the host galaxies. There is no evidence of any correlation between the levels of AGN and global star formation activity at all surveyed redshifts. We confirm that the star formation rates of AGN hosts increase strongly with redshift; by a factor of 43^{+27}_{-18} from z50 per cent at Mstars>10^{11}Msun. We argue that our findings imply that the majority of moderate nuclear activity is fuelled by internal mechanisms rather than violent mergers, which suggests that high redshift disk instabilities could be an important AGN feeding mechanism. Our results also show it is stellar mass that is most important in dictating whether a galaxy hosts...

  6. Contribution of the first galaxies to the cosmic far-infrared/sub-millimeter background - I. Mean background level

    CERN Document Server

    De Rossi, Maria Emilia

    2016-01-01

    We study the contribution of the first galaxies to the far-infrared/sub-millimeter (FIR/sub-mm) extragalactic background light (EBL) by implementing an analytical model for dust emission. We explore different dust models, assuming different grain size distributions and chemical compositions. According to our findings, observed re-radiated emission from dust in dwarf-size galaxies at $z \\sim 10$ would peak at a wavelength of $\\sim 500 \\mu {\\rm m}$ with observed fluxes of $\\sim 10^{-3} - 10^{-2}$ nJy, which is below the capabilities of current observatories. In order to be detectable, model sources at these high redshifts should exhibit luminosities of $\\gtrsim 10^{12} L_{\\odot}$, comparable to that of local ultra-luminous systems. The FIR/sub-mm EBL generated by primeval galaxies peaks at $\\sim 500 \\mu {\\rm m}$, with an intensity ranging from $\\sim 10^{-4}$ to $10^{-3} {\\rm nW \\ m^{-2} \\ sr^{-1}}$, depending on dust properties. These values are $\\sim 3 - 4$ orders of magnitude below the absolute measured cosmi...

  7. The interface between the stellar wind and interstellar medium around R Cassiopeiae revealed by far-infrared imaging

    CERN Document Server

    Ueta, T; Yamamura, I; Geise, K M; Karska, A; Izumiura, H; Nakada, Y; Matsuura, M; Ita, Y; Tanabe, T; Fukushi, H; Matsunaga, N; Mito, H; Speck, A K

    2009-01-01

    The circumstellar dust shells of intermediate initial-mass (about 1 to 8 solar masses) evolved stars are generated by copious mass loss during the asymptotic giant branch phase. The density structure of their circumstellar shell is the direct evidence of mass loss processes, from which we can investigate the nature of mass loss. We used the AKARI Infrared Astronomy Satellite and the Spitzer Space Telescope to obtain the surface brightness maps of an evolved star R Cas at far-infrared wavelengths, since the temperature of dust decreases as the distance from the star increases and one needs to probe dust at lower temperatures, i.e., at longer wavelengths. The observed shell structure and the star's known proper motion suggest that the structure represents the interface regions between the dusty wind and the interstellar medium. The deconvolved structures are fitted with the analytic bow shock structure to determine the inclination angle of the bow shock cone. Our data show that (1) the bow shock cone of 1 - 5 x...

  8. Micro-Spec: An Ultra-Compact, High-Sensitivity Spectrometer for Far-Infrared and Sub-Millimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe; Hsieh, Wen-Ting; Huang, Wei-Chung; Moseley, S. Harvey; Stevenson, Thomas R.; Wollack, Edward J.

    2013-01-01

    High-performance, integrated spectrometers operating in the far-infrared and sub-millimeter promise to be powerful tools for the exploration of the epochs of reionization and initial galaxy formation. These devices, using high-efficiency superconducting transmission lines, can achieve the performance of a meter-scale grating spectrometer in an instrument implemented on a four-inch silicon wafer. Such a device, when combined with a cryogenic telescope in space, provides an enabling capability for studies of the early universe. Here, the optical design process for Micro-Spec (mu-Spec) is presented, with particular attention given to its two-dimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the stigmatization and minimization of the light path function in this bounded region, which results in an optimized geometrical configuration. A point design with an efficiency of approx. 90% has been developed for initial demonstration, and can serve as the basis for future instruments. Design variations on this implementation are also discussed, which can lead to lower efficiencies due to diffractive losses in the multimode region.

  9. Fabricating interlocking support walls, with an adjustable backshort, in a TES bolometer array for far-infrared astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Timothy M. [NASA Goddard Space Flight Center, Detector Systems Branch Code 553, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); QSS Group, Inc., 4500 Forbes Blvd. Suite 200, Lanham, MD 20706 (United States); Abrahams, John H. [NASA Goddard Space Flight Center, Detector Systems Branch Code 553, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); QSS Group, Inc., 4500 Forbes Blvd. Suite 200, Lanham, MD 20706 (United States); Allen, Christine A. [NASA Goddard Space Flight Center, Detector Systems Branch Code 553, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)]. E-mail: callen@pop500.gsfc.nasa.gov

    2006-04-15

    We report a fabrication process for deep etching silicon to different depths with a single masking layer, using standard masking and exposure techniques. Using this technique, we have incorporated a deep notch in the support walls of a transition-edge-sensor (TES) bolometer array during the detector back-etch, while simultaneously creating a cavity behind the detector. The notches serve to receive the support beams of a separate component, the Backshort-Under-Grid (BUG), an array of adjustable height quarter-wave backshorts that fill the cavities behind each pixel in the detector array. The backshort spacing, set prior to securing to the detector array, can be controlled from 25 to 300 {mu}m by adjusting only a few process steps. In addition to backshort spacing, the interlocking beams and notches provide positioning and structural support for the {approx}1 mm pitch, 8x8 array. This process is being incorporated into developing a TES bolometer array with an adjustable backshort for use in far-infrared astronomy. The masking technique and machining process used to fabricate the interlocking walls will be discussed.

  10. Effects of far-infrared irradiation on myofascial neck pain: a randomized, double-blind, placebo-controlled pilot study.

    Science.gov (United States)

    Lai, Chien-Hung; Leung, Ting-Kai; Peng, Chih-Wei; Chang, Kwang-Hwa; Lai, Ming-Jun; Lai, Wen-Fu; Chen, Shih-Ching

    2014-02-01

    The objective of this study was to determine the relative efficacy of irradiation using a device containing a far-infrared emitting ceramic powder (cFIR) for the management of chronic myofascial neck pain compared with a control treatment. This was a randomized, double-blind, placebo-controlled pilot study. The study comprised 48 patients with chronic, myofascial neck pain. Patients were randomly assigned to the experimental group or the control (sham-treatment) group. The patients in the experimental group wore a cFIR neck device for 1 week, and the control group wore an inert neck device for 1 week. Quantitative measurements based on a visual analogue scale (VAS) scoring of pain, a sleep quality assessment, pressure-pain threshold (PPT) testing, muscle tone and compliance analysis, and skin temperature analysis were obtained. Both the experimental and control groups demonstrated significant improvement in pain scores. However, no statistically significant difference in the pain scores was observed between the experimental and control groups. Significant decreases in muscle stiffness in the upper regions of the trapezius muscles were reported in the experimental group after 1 week of treatment. Short-term treatment using the cFIR neck device partly reduced muscle stiffness. Although the differences in the VAS and PPT scores for the experimental and control groups were not statistically significant, the improvement in muscle stiffness in the experimental group warrants further investigation of the long-term effects of cFIR treatment for pain management.

  11. Analysis of Precursors Prior to Rock Burst in Granite Tunnel Using Acoustic Emission and Far Infrared Monitoring

    Directory of Open Access Journals (Sweden)

    Zhengzhao Liang

    2013-01-01

    Full Text Available To understand the physical mechanism of the anomalous behaviors observed prior to rock burst, the acoustic emission (AE and far infrared (FIR techniques were applied to monitor the progressive failure of a rock tunnel model subjected to biaxial stresses. Images of fracturing process, temperature changes of the tunnel, and spatiotemporal serials of acoustic emission were simultaneously recorded during deformation of the model. The b-value derived from the amplitude distribution data of AE was calculated to predict the tunnel rock burst. The results showed that the vertical stress enhanced the stability of the tunnel, and the tunnels with higher confining pressure demonstrated a more abrupt and strong rock burst. Abnormal temperature changes around the wall were observed prior to the rock burst of the tunnel. Analysis of the AE events showed that a sudden drop and then a quiet period could be considered as the precursors to forecast the rock burst hazard. Statistical analysis indicated that rock fragment spalling occurred earlier than the abnormal temperature changes, and the abnormal temperature occurred earlier than the descent of the AE b-value. The analysis indicated that the temperature changes were more sensitive than the AE b-value changes to predict the tunnel rock bursts.

  12. The far infrared spectrum of naphthalene characterized by high resolution synchrotron FTIR spectroscopy and anharmonic DFT calculations.

    Science.gov (United States)

    Pirali, O; Goubet, M; Huet, T R; Georges, R; Soulard, P; Asselin, P; Courbe, J; Roy, P; Vervloet, M

    2013-07-07

    Using synchrotron radiation, we performed the rotationally resolved Fourier transform infrared absorption spectroscopy of three bands of naphthalene C10H8, namely ν(46)-0 (centered at 782 cm(-1), 12.7 μm), ν(47)-0 (centered at 474 cm(-1), 21 μm), and ν(48)-0 (centered at 167 cm(-1), 60 μm). The intense CH bending out of plane ν(46)-0 band was recorded under supersonic jet-cooled conditions using a molecular beam (the Jet-AILES apparatus) and the low frequency ν(47)-0 and ν(48)-0 bands were measured at room temperature in a long absorption path cell. The simultaneous rotational analysis of these bands permitted us to refine the ground state (GS) and ν(46) rotational spectroscopic constants and to provide the first sets of constants for the ν(47) and ν(48) modes. The experimental rotational constants were then used as reference data to calibrate theoretical models in order to provide new insights into the accuracy of anharmonic calculations. The B97-1 functional associated with the cc-pVTZ and ANO-RCC basis sets gave a consistent set of results, for rotational constants and fundamental frequencies. The data presented here pave the way for the search of naphthalene through its far-infrared spectrum in different objects of the interstellar medium.

  13. An Array of One-Dimensional Porous Silicon Photonic Crystal Reflector Islands for a Far-Infrared Image Detector

    Institute of Scientific and Technical Information of China (English)

    MIAO Feng-Juan; ZHANG Jie; XU Shao-Hui; WANG Lian-Wei; CHU Jun-Hao; CAO Zhi-Shen; ZHAN Peng; WANG Zhen-Lin

    2009-01-01

    @@ With the aid of photolithography, an array of one-dimensional porous silicon photonic crystal reflector islands for a far infrared image detector ranging from 10μm to 14μm is successfully fabricated. Silicon nitride formed by low pressure chemical vapor deposition (LPCVD) was used as the masking layer for the island array formation. After etching, the microstructures were examined by a scanning electron microscope and the optical properties were studied by Fourier transform infrared spectroscopy, the result indicates that the multilayer structure could be obtained in the perpendicular direction via periodically alternative etching current in each pre-patteru. At the same time, the island array has a well-proportioned lateral etching effect, which is very useful for the thermal isolation in lateral orientation of the application in devices. It is concluded that regardless of the absorption of the deposition layer on the substrate, the localized photonic crystalline islands have higher reflectivity. The designed islands structure not only prevents the cracking of the porous silicon layers but is also useful for the application in the cold part for the sensor devices and the interconnection of each pixel.

  14. The relationship between polycyclic aromatic hydrocarbon emission and far-infrared dust emission from NGC 2403 and M83

    CERN Document Server

    Jones, A G; Baes, M; Boquien, M; Boselli, A; De Looze, I; Fritz, J; Galliano, F; Hughes, T M; Lebouteiller, V; Lu, N; Madden, S C; Remy-Ruyer, A; Smith, M W L; Spinoglio, L; Zijlstra, A A

    2014-01-01

    We examine the relation between polycyclic aromatic hydrocarbon (PAH) emission at 8 microns and far-infrared emission from hot dust grains at 24 microns and from large dust grains at 160 and 250 microns in the nearby spiral galaxies NGC 2403 and M83 using data from the Spitzer Space Telescope and Herschel Space Observatory. We find that the PAH emission in NGC 2403 is better correlated with emission at 250 microns from dust heated by the diffuse interstellar radiation field (ISRF) and that the 8/250 micron surface brightness ratio is well-correlated with the stellar surface brightness as measured at 3.6 microns. This implies that the PAHs in NGC 2403 are intermixed with cold large dust grains in the diffuse interstellar medium (ISM) and that the PAHs are excited by the diffuse ISRF. In M83, the PAH emission appears more strongly correlated with 160 micron emission originating from large dust grains heated by star forming regions. However, the PAH emission in M83 is low where the 24 micron emission peaks withi...

  15. KINGFISH -- Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel: Survey Description and Image Atlas

    CERN Document Server

    Kennicutt, R C; Aniano, G; Appleton, P; Armus, L; Beirao, P; Bolatto, A D; Brandl, B; Crocker, A; Croxall, K; Dale, D A; Meyer, J Dononvan; Draine, B T; Engelbracht, C W; Galametz, M; Gordon, K D; Groves, B; Hao, C -N; Helou, G; Hinz, J; Hunt, L K; Johnson, B; Koda, J; Krause, O; Leroy, A K; Li, Y; Meidt, S; Montiel, E; Murphy, E J; Rahman, N; Rix, H -W; Roussel, H; Sandstrom, K; Sauvage, M; Schinnerer, E; Skibba, R; Smith, J -D T; Srinivasan, S; Vigroux, L; Walter, F; Wilson, C D; Wolfire, M; Zibetti, S

    2011-01-01

    The KINGFISH project (Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel) is an imaging and spectroscopic survey of 61 nearby (d < 30 Mpc) galaxies, chosen to cover a wide range of galaxy properties and local interstellar medium (ISM) environments found in the nearby Universe. Its broad goals are to characterize the ISM of present-day galaxies, the heating and cooling of their gaseous and dust components, and to better understand the physical processes linking star formation and the ISM. KINGFISH is a direct descendant of the Spitzer Infrared Nearby Galaxies Survey (SINGS), which produced complete Spitzer imaging and spectroscopic mapping and a comprehensive set of multi-wavelength ancillary observations for the sample. The Herschel imaging consists of complete maps for the galaxies at 70, 100, 160, 250, 350, and 500 microns. The spectal line imaging of the principal atomic ISM cooling lines ([OI]63um, [OIII]88um, [NII]122,205um, and [CII]158um) covers the subregions in the centers and di...

  16. Detection of Far-Infrared Water Vapor, Hydroxyl, and Carbon Monoxide Emissions from the Supernova Remnant 3C 391

    CERN Document Server

    Reach, W T; Reach, William T.; Rho, Jeonghee

    1998-01-01

    We report the detection of shock-excited far-infrared emission of H2O, OH, and CO from the supernova remnant 3C 391, using the ISO Long-Wavelength Spectrometer. This is the first detection of thermal H2O and OH emission from a supernova remnant. For two other remnants, W~28 and W~44, CO emission was detected but OH was only detected in absorption. The observed H2O and OH emission lines arise from levels within ~400 K of the ground state, consistent with collisional excitation in warm, dense gas created after the passage of the shock front through the dense clumps in the pre-shock cloud. The post-shock gas we observe has a density ~2x10^5 cm^{-3} and temperature 100-1000 K, and the relative abundances of CO:OH:H2O in the emitting region are 100:1:7 for a temperature of 200 K. The presence of a significant column of warm H2O suggests that the chemistry has been significantly changed by the shock. The existence of significant column densities of both OH and H2O, which is at odds with models for non-dissociative ...

  17. How cosmic-ray electron propagation affects radio-far-infrared correlations in M31 and M33

    CERN Document Server

    Berkhuijsen, Elly M; Tabatabaei, Fatemeh S

    2013-01-01

    We investigate the effect of propagation of cosmic-ray electrons (CRE) on the nonthermal (synchrotron) - far-infrared correlations in M31 and M33. The thermal (TH) and nonthermal (NTH) emission components of the radio continuum emission at 1.4 GHz and one higher frequency are compared with dust emission from M31 and M33 using Spitzer data. In both galaxies the TH emission is linearly correlated with the emission from warm dust (24 \\mu m, 70 \\mu m), but the power laws of the NTH-FIR correlations have exponents b < 1 that increase with increasing frequency. Furthermore, the values of b for M33 are significantly smaller (b ~ 0.4) than those for M31 (b ~ 0.6). We interpret the differences in b as differences in the diffusion length of the CRE. We estimate the diffusion length in two ways: (1) by smoothing the NTH emission at the higher frequency until the correlation with NTH emission at 1.4 GHz has b = 1, and (2) by smoothing the TH emission until the correlation with the NTH emission at the same frequency ha...

  18. A kilo-pixel imaging system for future space based far-infrared observatories using microwave kinetic inductance detectors

    CERN Document Server

    Baselmans, J J A; Yates, S J C; Yurduseven, O; Llombart, N; Karatsu, K; Baryshev, A M; Ferrari, L; Endo, A; Thoen, D J; de Visser, P J; Janssen, R M J; Murugesan, V; Driessen, E F C; Coiffard, G; Martin-Pintado, J; Hargrave, P; Griffin, M

    2016-01-01

    Future astrophysics and cosmic microwave background space missions operating in the far-infrared to millimetre part of the spectrum will require very large arrays of ultra-sensitive detectors in combination with high multiplexing factors and efficient low- noise and low-power readout systems. We have developed a demonstrator system suitable for such applications. The system combines a 961 pixel imaging array based upon Microwave Kinetic Inductance Detectors (MKIDs) with a readout system capable of reading out all pixels simultaneously with only one readout cable pair and a single cryogenic amplifier. We evaluate, in a representative environment, the system performance in terms of sensitivity, dynamic range, optical efficiency, cosmic ray rejection, pixel-pixel crosstalk and overall yield at an observation frequency of 850 GHz. The overall system has an excellent sensitivity, with an average detector sensitivity NEP=2.8 +- 0.8 x 10^-19 W/rt(Hz) measured using a thermal calibration source. The dynamic range wou...

  19. Detection of pedestrians in far-infrared automotive night vision using region-growing and clothing distortion compensation

    Science.gov (United States)

    O'Malley, Ronan; Jones, Edward; Glavin, Martin

    2010-11-01

    We present a night-time pedestrian detection system based on automotive infrared video processing. Far-infrared or thermal night vision is a technology well suited for automatic detection of pedestrians at night as they generally appear warmer than the background. However, the appearance of a pedestrian in IR video can vary dramatically depending on the physical properties of the clothing they wear, the time spent adjusting to the outside environment, and the ambient temperature. We highlight the difficulties of detection in low temperatures (below 8 °C) when pedestrians typically wear highly insulating clothing, which can lead to distortion of the IR signature of the pedestrian. A pre-processing step is presented, which compensates for this clothing-based distortion using vertically-biased morphological closing. Potential pedestrians (Regions of Interest) are then segmented using feature-based region-growing with high intensity seeds. Histogram of Oriented Gradients (HOG) features are extracted from candidates and utilised for Support Vector Machine classification. Positively classified targets are tracked between frames using a Kalman filter, adding robustness and increasing performance. The proposed system adapts not just to variations between images or video frames, but to variations in appearance between different pedestrians in the same image or frame. Results indicate improved performance compared to previous HOG-SVM automotive IR pedestrian detection systems, which utilised stereo IR cameras.

  20. The cosmic far-infrared background buildup since redshift 2 at 70 and 160 microns in the COSMOS and GOODS fields

    NARCIS (Netherlands)

    Jauzac, M.; Dole, H.; Le Floc'h, E.; Aussel, H.; Caputi, K.; Ilbert, O.; Salvato, M.; Bavouzet, N.; Beelen, A.; Bethermin, M.; Kneib, J. -P.; Lagache, G.; Puget, J. -L.

    2011-01-01

    Context. The cosmic far-infrared background (CIB) at wavelengths around 160 mu m corresponds to the peak intensity of the whole extragalactic background light, which is being measured with increasing accuracy. However, the build up of the CIB emission as a function of redshift is still not well know

  1. Using phonon resonances as a route to all-angle negative refraction in the far-infrared region: the case of crystal quartz.

    Science.gov (United States)

    Rodrigues da Silva, R; Macêdo da Silva, R; Dumelow, T; da Costa, J A P; Honorato, S B; Ayala, A P

    2010-10-15

    We consider how all-angle negative refraction may be induced in anisotropic crystals by making use of the phonon response. We investigate the example of crystal quartz at far-infrared wavelengths. Reflection and transmission measurements confirm the expected behavior, and show relatively high transmission efficiency at frequencies at which negative refraction occurs.

  2. Generation of Frequency-Chirped Pulses in the Far-Infrared by Means of a Subpicosecond Free-Electron Laser and an External Pulse Shaper

    NARCIS (Netherlands)

    Knippels, G.M.H.; van der Meer, A. F. G.; Mols, Rfxam; van Amersfoort, P. W.; Vrijen, R. B.; Maas, D. J.; Noordam, L. D.

    1995-01-01

    The generation of frequency-chirped optical pulses in the far-infrared is reported. The pulses are produced by the free-electron laser FELIX. The chirp is induced by means of an external shaping device consisting of a grating and a telescope. The shaper is based on reflective optics to permit operat

  3. Far-infrared laser action in vinyl chloride, vinyl bromide, and vinyl fluoride optically pumped by a CW N2O laser

    Science.gov (United States)

    Gastaud, C.; Redon, M.; Belland, P.; Fourrier, M.

    1984-06-01

    This paper reports the first use of a N2O laser for optically pumping vinyl halides, to obtain new cw submillimeter laser lines. Eighteen far-infrared (FIR) emissions have been observed in vinyl chloride, twenty five in vinyl bromide and thirty eight in vinyl flouride.

  4. Far-Infrared Line and Continuum Observations of G0.095 + 0.012 and the E2 Thermal Radio Filament Near the Galactic Center

    Science.gov (United States)

    Erickson, Edwin F.; Colgan, Sean W. J.; Simpson, J. P.; Rubin, Robert H.; Morris, Mark; Haas, Michael R.

    1991-01-01

    Measurements of far-infrared lines and continuum from GO.095 + 0.012 and the E2 thermal 'arched' radio filament near the Galactic center are well explained by numerous embedded stars with T(sub eff) approximately 35,000 K. The structure of the filament and the apparent absence of hotter stars are qualitatively difficult to reconcile with this idea.

  5. Interstellar ice analogs: band strengths of H$_2$O, CO$_2$, CH$_3$OH, and NH$_3$ in the far-infrared region

    CERN Document Server

    Giuliano, B M; Martín-Doménech, R; Dartois, E; Caro, G M Muñoz

    2014-01-01

    We measure the band strengths in the far-infrared region of interstellar ice analogs of astrophysically relevant species, such as H$_2$O, CO$_2$, CH$_3$OH, and NH$_3$, deposited at low temperature (8-10 $\\mathrm{K}$), followed by warm-up, to induce amorphous-crystalline phase transitions when relevant. The spectra of pure H$_2$O, NH$_3$, and CH$_3$OH ices have been measured in the near-, mid- and far-infrared spectroscopic regions using the Interstellar Astrochemistry Chamber (ISAC) ultra-high-vacuum setup. In addition, far-infrared spectra of NH$_3$ and CO$_2$ were measured using a different set-up equipped with a bolometer detector. Band strengths in the far-infrared region were estimated using the corresponding near- and mid-infrared values as a reference. We also performed theoretical calculations of the amorphous and crystalline structures of these molecules using solid state computational programs at density functional theory (DFT) level. Vibrational assignment and mode intensities for these ices were p...

  6. The interstellar gas seen in the mid- and far-infrared: The promise of SPICA Space Telescope

    CERN Document Server

    Goicoechea, Javier R

    2009-01-01

    The mid- and far-IR spectral ranges are critical windows to characterize the physical and chemical processes that transform the interstellar gas and dust into stars and planets. Sources in the earliest phases of star formation and in the latest stages of stellar evolution release most of their energy at these wavelengths. Besides, the mid- and far-IR ranges provide key spectral diagnostics of the gas chemistry (water, light hydrides, organic species ...), of the prevailing physical conditions (H2, atomic fine structure lines...), and of the dust mineral and ice composition that can not be observed from ground-based telescopes. With the launch of JAXA's SPICA telescope, uninterrupted studies in the mid- and far-IR will be possible since ESA's Infrared Space Observatory (1995). In particular, SAFARI will provide full access to the 34-210um waveband through several detector arrays and flexible observing modes (from broadband photometry to medium resolution spectroscopy with R~3,000 at 63um), and reaching very hi...

  7. The complete far-infrared and submillimeter spectrum of the Class 0 protostar Serpens SMM1 obtained with Herschel

    DEFF Research Database (Denmark)

    R. Goicoechea, Javier; Cernicharo, J.; Karska, A.

    2012-01-01

    We present the first complete 55-671 um spectral scan of a low-mass Class 0 protostar (Serpens SMM1) taken with the PACS and SPIRE spectrometers on board Herschel. More than 145 lines have been detected, most of them rotationally excited lines of 12CO (full ladder from J=4-3 to 42-41), H2O, OH, 13......(warm)~375 K and Tk(cool)~150 K). Gas densities n(H2)~5x10^6 cm^-3 are needed to reproduce the observed far-IR lines arising from shocks in the inner protostellar envelope for which we derive upper limit abundances of x(CO)~10^-4, x(H2O)~0.2x10^-5 and x(OH)~10^-6. The lower energy submm 12CO and H2O lines...

  8. Mean Spectral Energy Distributions and Bolometric Corrections for Luminous Quasars

    CERN Document Server

    Krawczyk, Coleman M; Mehta, Sajjan S; Vogeley, Michael S; Gallagher, S C; Leighly, Karen M; Ross, Nicholas P; Schneider, Donald P; 10.1088/0067-0049/206/1/4

    2013-01-01

    We explore the mid-infrared (mid-IR) through ultraviolet (UV) spectral energy distributions (SEDs) of 119,652 luminous broad-lined quasars with 0.0641.6; the latter is a possible indicator of the strength of the accretion disk wind, which is expected to be SED dependent. Luminosity-dependent mean SEDs show that, relative to the high-luminosity SED, low-luminosity SEDs exhibit a harder (bluer) far-UV spectral slope, a redder optical continuum, and less hot dust. Mean SEDs constructed instead as a function of UV emission line properties reveal changes that are consistent with known Principal Component Analysis (PCA) trends. A potentially important contribution to the bolometric correction is the unseen extream-UV (EUV) continuum. Our work suggests that lower-luminosity quasars and/or quasars with disk-dominated broad emission lines may require an extra continuum component in the EUV that is not present (or much weaker) in high-luminosity quasars with strong accretion disk winds. As such, we consider four possib...

  9. Fermi energy 5f spectral weight variation in uranium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Denlinger, J.D.; Clack, J.; Allen, J.W. [Univ. of Michigan, Ann Arbor, MI (United States)] [and others

    1997-04-01

    Uranium materials display a wide range of thermal, electrical and magnetic properties, often exotic. For more than a decade there have been efforts to use photoemission spectroscopy to develop a systematic and unified understanding of the 5f electron states giving rise to this behavior. These efforts have been hampered by a paucity of systems where changes in transport properties are accompanied by substantial spectral changes, so as to allow an attempt to correlate the two kinds of properties within some model. The authors have made resonant photoemission measurements to extract the 5f spectral weight in three systems which show varying degrees of promise of permitting such an attempt, Y{sub 1{minus}x}U{sub x}Pd{sub 3}, U(Pd{sub x}Pt{sub 1{minus}x}){sub 3} and U(Pd{sub x}Cu{sub 1{minus}x}){sub 5}. They have also measured U 4f core level spectra. The 4f spectra can be modeled with some success by the impurity Anderson model (IAM), and the 5f spectra are currently being analyzed in that framework. The IAM characterizes the 5f-electrons of a single site by an f binding energy {epsilon}{sub f}, an f Coulomb interaction and a hybridization V to conduction electrons. Latent in the model are the phenomena of 5f mixed valence and the Kondo effect.

  10. 基于光子晶体的远红外与激光兼容伪装材料%Far infrared and laser band compatible camouflage material based on photonic crystals

    Institute of Scientific and Technical Information of China (English)

    高永芳; 时家明; 赵大鹏

    2011-01-01

    现代探测系统由单一工作模式向复合工作模式转变,对伪装材料的光谱特性提出了某些特殊要求.光子晶体是一种新型的人工结构功能材料,基于光子禁带的高反射特性,可以实现红外伪装;基于一维掺杂光子晶体,可以实现远红外与激光兼容伪装.设计了一种基于光子晶体的远红外与激光兼容伪装材料,利用薄膜光学理论的特征矩阵法计算了反射光谱,发现可以在反射光谱中的高反射率波段内形成局部窄带低反射区.结果表明:利用一维掺杂光子晶体可以实现远红外与激光兼容伪装.%As the working mode of modem detecting system is changing from single mode to compound one, the spectral characteristics of camouflage materials are required to meet some special requirements.As a new kind of artificial structure function material, photonic crystals can realize infrared camouflage because of its high-efficiency reflection characteristic of photonic band gap; based on one dimensional doped photonic crystal, it can realize far infrared and laser band compatible camouflage.A kind of far infrared and laser band compatible camouflage material was designed, then the reflectance spectrum was calculated by characteristic matrix method based on thin-film optical theory.It was found that a local narrow band low-reflectivity region could be formed within a high -reflectivity band in reflection spectrum.The result shows that one dimensional doped photonic crystal can achieve far infrared and laser band compatible camouflage.

  11. Far-Infrared Spectroscopy of Cationic Polycyclic Aromatic Hydrocarbons: Zero Kinetic Energy Photoelectron Spectroscopy of Pentacene Vaporized from Laser Desorption

    CERN Document Server

    Zhang, J; Pei, L; Kong, W; Li, Aigen

    2012-01-01

    The distinctive set of infrared (IR) emission bands at 3.3, 6.2, 7.7, 8.6, and 11.3{\\mu}m are ubiquitously seen in a wide variety of astrophysical environments. They are generally attributed to polycyclic aromatic hydrocarbon (PAH) molecules. However, not a single PAH species has yet been identified in space, as the mid-IR vibrational bands are mostly representative of functional groups and thus do not allow one to fingerprint individual PAH molecules. In contrast, the far-IR (FIR) bands are sensitive to the skeletal characteristics of a molecule, hence they are important for chemical identification of unknown species. With an aim to offer laboratory astrophysical data for the Herschel Space Observatory, Stratospheric Observatory for Infrared Astronomy, and similar future space missions, in this work we report neutral and cation FIR spectroscopy of pentacene (C_22H_14), a five-ring PAH molecule. We report three IR active modes of cationic pentacene at 53.3, 84.8, and 266{\\mu}m that may be detectable by space ...

  12. Simulated Galaxy Interactions as Probes of Merger Spectral Energy Distributions

    CERN Document Server

    Lanz, Lauranne; Zezas, Andreas; Smith, Howard A; Ashby, Matthew L N; Brassington, Nicola; Fazio, Giovanni G; Hernquist, Lars

    2014-01-01

    We present the first systematic comparison of ultraviolet-millimeter spectral energy distributions (SEDs) of observed and simulated interacting galaxies. Our sample is drawn from the Spitzer Interacting Galaxy Survey, and probes a range of galaxy interaction parameters. We use 31 galaxies in 14 systems which have been observed with Herschel, Spitzer, GALEX, and 2MASS. We create a suite of GADGET-3 hydrodynamic simulations of isolated and interacting galaxies with stellar masses comparable to those in our sample of interacting galaxies. Photometry for the simulated systems is then calculated with the SUNRISE radiative transfer code for comparison with the observed systems. For most of the observed systems, one or more of the simulated SEDs match reasonably well. The best matches recover the infrared luminosity and the star formation rate of the observed systems, and the more massive systems preferentially match SEDs from simulations of more massive galaxies. The most morphologically distorted systems in our sa...

  13. AGN Spectral Energy Distributions of GLAST Telescope Network Program Objects

    Science.gov (United States)

    Adkins, Jeff; Lacy, Mark; Daou, Doris; Rapp, Steve; Stefaniak, Linda

    2005-03-01

    The Gamma-Ray Large Area Space Telescope (GLAST) has a proposed observing list that includes AGNs and Polars bright enough to be observed optically by amateurs and students. This observing list is maintained by the "GLAST Telescope Network" (GTN) and includes a number of objects that have yet to be observed by the Spitzer Space Telescope. Our project will observe one of these objects with the Spitzer MIPS and the IRAC instruments to determine their Spectral Energy Distribution (SED), which will be compared to a computer model of disk emission in order to determine what component of the SED is due to the disk and what component is due to synchrotron radiation induced by the jets. In addition we will observe our program objects prior to, simultaneously with, and after Spitzer observes them. This gives a direct connection from Spitzer research to student activities in the classroom.

  14. STAR FORMATION RATES IN RESOLVED GALAXIES: CALIBRATIONS WITH NEAR- AND FAR-INFRARED DATA FOR NGC 5055 AND NGC 6946

    Energy Technology Data Exchange (ETDEWEB)

    Li Yiming; Crocker, Alison F.; Calzetti, Daniela [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Wilson, Christine D. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Kennicutt, Robert C.; Galametz, M. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Murphy, Eric J. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Brandl, Bernhard R.; Groves, B. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Draine, B. T. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Johnson, B. D. [Institut d' Astrophysique de Paris, UMR7095 CNRS, Universite Pierre and Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Armus, L. [Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States); Gordon, K. D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Croxall, K. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Dale, D. A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Engelbracht, C. W.; Hinz, J. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Hao, C.-N. [Tianjin Astrophysics Center, Tianjin Normal University, Tianjin 300387 (China); Helou, G. [NASA Herschel Science Center, IPAC, California Institute of Technology, Pasadena, CA 91125 (United States); Hunt, L. K., E-mail: yimingl@astro.umass.edu [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); and others

    2013-05-10

    We use the near-infrared Br{gamma} hydrogen recombination line as a reference star formation rate (SFR) indicator to test the validity and establish the calibration of the Herschel/PACS 70 {mu}m emission as a SFR tracer for sub-galactic regions in external galaxies. Br{gamma} offers the double advantage of directly tracing ionizing photons and of being relatively insensitive to the effects of dust attenuation. For our first experiment, we use archival Canada-France-Hawaii Telescope Br{gamma} and Ks images of two nearby galaxies: NGC 5055 and NGC 6946, which are also part of the Herschel program KINGFISH (Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel). We use the extinction corrected Br{gamma} emission to derive the SFR(70) calibration for H II regions in these two galaxies. A comparison of the SFR(70) calibrations at different spatial scales, from 200 pc to the size of the whole galaxy, reveals that about 50% of the total 70 {mu}m emission is due to dust heated by stellar populations that are unrelated to the current star formation. We use a simple model to qualitatively relate the increase of the SFR(70) calibration coefficient with decreasing region size to the star formation timescale. We provide a calibration for an unbiased SFR indicator that combines the observed H{alpha} with the 70 {mu}m emission, also for use in H II regions. We briefly analyze the PACS 100 and 160 {mu}m maps and find that longer wavelengths are not as good SFR indicators as 70 {mu}m, in agreement with previous results. We find that the calibrations show about 50% difference between the two galaxies, possibly due to effects of inclination.

  15. Investigating the relation between CO (3-2) and far-infrared luminosities for nearby merging galaxies using ASTE

    Science.gov (United States)

    Michiyama, Tomonari; Iono, Daisuke; Nakanishi, Kouichiro; Ueda, Junko; Saito, Toshiki; Ando, Misaki; Kaneko, Hiroyuki; Yamashita, Takuji; Matsuda, Yuichi; Hatsukade, Bunyo; Kikuchi, Kenichi; Komugi, Shinya; Muto, Takayuki

    2016-09-01

    We present the new single-dish CO (3-2) emission data obtained toward 19 early-stage and 7 late-stage nearby merging galaxies using the Atacama Submillimeter Telescope Experiment (ASTE). Combining with the single-dish and interferometric data of galaxies observed in previous studies, we investigate the relation between the CO (3-2) luminosity (L^' }_CO(3-2)) and the far-infrared luminosity (LFIR) in a sample of 29 early-stage and 31 late-stage merging galaxies, and 28 nearby isolated spiral galaxies. We find that normal isolated spiral galaxies and merging galaxies have different slopes (α) in the log L^' }_CO(3-2)-log LFIR plane (α ˜ 0.79 for spirals and ˜1.12 for mergers). The large slope (α > 1) for merging galaxies can be interpreted as evidence for increasing star formation efficiency (SFE = L_FIR/L^' }_CO(3-2)) as a function of LFIR. Comparing our results with sub-kpc-scale local star formation and global starburst activity in the high-z universe, we find deviations from the linear relationship in the log L^' }_CO(3-2)-log LFIR plane for the late-stage mergers and high-z star-forming galaxies. Finally, we find that the average SFE gradually increases from isolated galaxies to merging galaxies and to high-z submillimeter galaxies/quasi-stellar objects. By comparing our findings with results from numerical simulations, we suggest that: (1) inefficient starbursts triggered by disk-wide dense clumps occur in the early stage of interaction, and (2) efficient starbursts triggered by central concentration of gas occur in the final stage. A systematic high spatial resolution survey of diffuse- and dense-gas tracers is the key to confirming this scenario.

  16. Comparison of laser-based mitigation of fused silica surface damage using mid- versus far-infrared lasers

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S T; Matthews, M J; Elhadj, S; Cooke, D; Guss, G M; Draggoo, V G; Wegner, P J

    2009-12-16

    Laser induced growth of optical damage can limit component lifetime and therefore operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, they quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {micro}m) versus far-IR (10.6 {micro}m) lasers in mitigating damage growth on fused silica surfaces. The non-linear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda} = 4.6 {micro}m, while far-IR laser heating is well-described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on infrared radiometry, as well as sub-surface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally-ablative conditions. Based on their FOM, they show that for cracks up to at least 500 {micro}m in depth, mitigation with a 4.6 {micro}m mid-IR laser is more efficient than mitigation with a 10.6 {micro}m far-IR laser. This conclusion is corroborated by direct application of each laser system to the mitigation of pulsed laser-induced damage possessing fractures up to 225 {micro}m in depth.

  17. Low-volume aluminum and aluminum / titanium nitride bilayer lumped-element kinetic inductance detectors for far-infrared astronomy

    Science.gov (United States)

    Glenn, Jason; Fyhrie, Adalyn; Wheeler, Jordan; Day, Peter K.; Eom, Byeong H.; Leduc, Henry G.

    2016-07-01

    We present the design and characterization of low-volume, lumped-element aluminum kinetic inductance de- tectors for sensitive far-infrared astronomy observations. The lumped-element kinetic inductance detectors are comprised of meandered inductors that serve as radiation absorbers in parallel with interdigitated capacitors, forming high quality factor resonators. Low inductor volumes lead to low noise equivalent powers by raising quasiparticles densities, and hence responsivities, with respect to larger volumes. Low volumes are achieved with thin (20 nm), narrow (150 nm) inductors. The interdigitated capacitor architecture is designed to mitigate two-level system noise by lowering electric fields in the silicon substrate. Resonance frequencies are in the range of 190 to 500 MHz, with measured internal quality factors in excess of 1 x 105. In a prior incarnation, a titanium nitride layer on top of the aluminum served as a protective layer, but complicated the superconducting proper- ties. These results were reported previously. In the current incarnation, the aluminum layer is left bare with no titanium nitride over-layer. The results for these bare aluminum devices include a yield of 88%, frequency responsivity of 109 W-1, and noise equivalent power of 1 x 10-17 W Hz-1/2 for a 350μm array. There is no evidence for 1=f noise down to at least 200 mHz. The sensitivity is currently limited by white noise, very likely from stray light in the testbed; for this detector design, sensitivities limited by generation-recombination noise in a lower-background environment should be several orders of magnitude lower.

  18. A kilo-pixel imaging system for future space based far-infrared observatories using microwave kinetic inductance detectors

    Science.gov (United States)

    Baselmans, J. J. A.; Bueno, J.; Yates, S. J. C.; Yurduseven, O.; Llombart, N.; Karatsu, K.; Baryshev, A. M.; Ferrari, L.; Endo, A.; Thoen, D. J.; de Visser, P. J.; Janssen, R. M. J.; Murugesan, V.; Driessen, E. F. C.; Coiffard, G.; Martin-Pintado, J.; Hargrave, P.; Griffin, M.

    2017-05-01

    Aims: Future astrophysics and cosmic microwave background space missions operating in the far-infrared to millimetre part of the spectrum will require very large arrays of ultra-sensitive detectors in combination with high multiplexing factors and efficient low-noise and low-power readout systems. We have developed a demonstrator system suitable for such applications. Methods: The system combines a 961 pixel imaging array based upon Microwave Kinetic Inductance Detectors (MKIDs) with a readout system capable of reading out all pixels simultaneously with only one readout cable pair and a single cryogenic amplifier. We evaluate, in a representative environment, the system performance in terms of sensitivity, dynamic range, optical efficiency, cosmic ray rejection, pixel-pixel crosstalk and overall yield at an observation centre frequency of 850 GHz and 20% fractional bandwidth. Results: The overall system has an excellent sensitivity, with an average detector sensitivity =3×10-19 WHz measured using a thermal calibration source. At a loading power per pixel of 50 fW we demonstrate white, photon noise limited detector noise down to 300 mHz. The dynamic range would allow the detection of 1 Jy bright sources within the field of view without tuning the readout of the detectors. The expected dead time due to cosmic ray interactions, when operated in an L2 or a similar far-Earth orbit, is found to be <4%. Additionally, the achieved pixel yield is 83% and the crosstalk between the pixels is <-30 dB. Conclusions: This demonstrates that MKID technology can provide multiplexing ratios on the order of a 1000 with state-of-the-art single pixel performance, and that the technology is now mature enough to be considered for future space based observatories and experiments.

  19. Contribution of the first galaxies to the cosmic far-infrared/sub-millimeter background - I. Mean background level

    Science.gov (United States)

    De Rossi, María Emilia; Bromm, Volker

    2017-03-01

    We study the contribution of the first galaxies to the far-infrared/sub-millimeter (FIR/sub-mm) extragalactic background light (EBL) by implementing an analytical model for dust emission. We explore different dust models, assuming different grain-size distributions and chemical compositions. According to our findings, observed reradiated emission from dust in dwarf-size galaxies at z ∼ 10 would peak at a wavelength of ∼ 500 μm with observed fluxes of ∼10-3-10-2 nJy, which is below the capabilities of current observatories. In order to be detectable, model sources at these high redshifts should exhibit luminosities of ≳1012 L⊙, comparable to that of local ultraluminous systems. The FIR/sub-mm-EBL generated by primeval galaxies peaks at ∼ 500 μm, with an intensity ranging from ∼10-4 to 10-3 nW m-2 sr-1, depending on dust properties. These values are ∼3-4 orders of magnitude below the absolute measured cosmic background level, suggesting that the first galaxies would not contribute significantly to the observed FIR/sub-mm-EBL. Our model EBL exhibits a strong correlation with the dust-to-metal ratio, where we assume a fiducial value of D = 0.005, increasing almost proportionally to it. Thus, measurements of the FIR/sub-mm-EBL could provide constraints on the amount of dust in the early Universe. Even if the absolute signal from primeval dust emission may be undetectable, it might still be possible to obtain information about it by exploring angular fluctuations at ∼ 500 μm, close to the peak of dust emission from the first galaxies.

  20. Enhanced photovoltaic energy conversion using thermally based spectral shaping

    Science.gov (United States)

    Bierman, David M.; Lenert, Andrej; Chan, Walker R.; Bhatia, Bikram; Celanović, Ivan; Soljačić, Marin; Wang, Evelyn N.

    2016-06-01

    Solar thermophotovoltaic devices have the potential to enhance the performance of solar energy harvesting by converting broadband sunlight to narrow-band thermal radiation tuned for a photovoltaic cell. A direct comparison of the operation of a photovoltaic with and without a spectral converter is the most critical indicator of the promise of this technology. Here, we demonstrate enhanced device performance through the suppression of 80% of unconvertible photons by pairing a one-dimensional photonic crystal selective emitter with a tandem plasma-interference optical filter. We measured a solar-to-electrical conversion rate of 6.8%, exceeding the performance of the photovoltaic cell alone. The device operates more efficiently while reducing the heat generation rates in the photovoltaic cell by a factor of two at matching output power densities. We determined the theoretical limits, and discuss the implications of surpassing the Shockley-Queisser limit. Improving the performance of an unaltered photovoltaic cell provides an important framework for the design of high-efficiency solar energy converters.

  1. HERSCHEL/PACS SPECTROSCOPIC SURVEY OF PROTOSTARS IN ORION: THE ORIGIN OF FAR-INFRARED CO EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Manoj, P.; Watson, D. M.; Yu, Vincent [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Neufeld, D. A. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Megeath, S. T.; Fischer, W. J.; Poteet, C. A. [Department of Physics and Astronomy, University of Toledo, 2801 West Bancroft Street, OH 43606 (United States); Vavrek, R. [European Space Agency, ESAC/SRE-OAH, P.O. Box 78, E-28691 Villanueva de la Canada, Madrid (Spain); Visser, R.; Bergin, E. A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Tobin, J. J. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Stutz, A. M. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Ali, B. [NHSC/IPAC/Caltech, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Wilson, T. L. [US Naval Research Laboratory, Code 7210, Washington, DC 20375 (United States); Di Francesco, J. [National Research Council of Canada, Herzberg Institute of Astrophysics, Department of Physics and Astronomy, University of Victoria, Victoria, BC V9E 2E7 (Canada); Osorio, M. [Instituto de Astrofisica de Andalucia, CSIC, Camino Bajo de Huetor 50, E-18008 Granada (Spain); Maret, S., E-mail: manoj@pas.rochester.edu [Laboratoire d' Astrophysique de Grenoble, Observatoire de Grenoble, Universite Joseph Fourier, CNRS, UMR 571, F-38041 Grenoble (France)

    2013-02-15

    We present far-infrared (57-196 {mu}m) spectra of 21 protostars in the Orion molecular clouds. These were obtained with the Photodetector Array Camera and Spectrometer (PACS) on board the Herschel Space observatory as part of the Herschel Orion Protostar Survey program. We analyzed the emission lines from rotational transitions of CO, involving rotational quantum numbers in the range J {sub up} = 14-46, using PACS spectra extracted within a projected distance of {approx}<2000 AU centered on the protostar. The total luminosity of the CO lines observed with PACS (L {sub CO}) is found to increase with increasing protostellar luminosity (L {sub bol}). However, no significant correlation is found between L {sub CO} and evolutionary indicators or envelope properties of the protostars such as bolometric temperature, T {sub bol}, or envelope density. The CO rotational (excitation) temperature implied by the line ratios increases with increasing rotational quantum number J, and at least 3-4 rotational temperature components are required to fit the observed rotational diagram in the PACS wavelength range. The rotational temperature components are remarkably invariant between protostars and show no dependence on L {sub bol}, T {sub bol}, or envelope density, implying that if the emitting gas is in local thermodynamic equilibrium, the CO emission must arise in multiple temperature components that remain independent of L {sub bol} over two orders of magnitudes. The observed CO emission can also be modeled as arising from a single-temperature gas component or from a medium with a power-law temperature distribution; both of these require sub-thermally excited molecular gas at low densities (n(H{sub 2}) {approx}< 10{sup 6} cm{sup -3}) and high temperatures (T {approx}> 2000 K). Our results suggest that the contribution from photodissociation regions, produced along the envelope cavity walls from UV-heating, is unlikely to be the dominant component of the CO emission observed with

  2. Strong far-infrared cooling lines, peculiar CO kinematics, and possible star-formation suppression in Hickson compact group 57

    Energy Technology Data Exchange (ETDEWEB)

    Alatalo, K.; Appleton, P. N.; Ogle, P. M.; Rich, J. A.; Xu, C. K. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Lisenfeld, U. [Departamento de Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada (Spain); Bitsakis, T. [NASA Herschel Science Center, IPAC, California Institute of Technology, Pasadena, CA 91125 (United States); Guillard, P. [Institut d' Astrophysique Spatiale, Université Paris-Sud XI, F-91405 Orsay Cedex (France); Charmandaris, V. [Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, GR-15236 Penteli (Greece); Cluver, M.; Jarrett, T. [Astrophysics Cosmology and Gravity Centre, Dept of Astronomy, University of Cape Town, Private Bag X3, Rondebosch, 7701, Republic of South Africa (South Africa); Dopita, M. A.; Kewley, L. J. [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston, ACT 2611 (Australia); Freeland, E. [The Oskar Klein Centre, Department of Astronomy, AlbaNova, Stockholm University, SE-106 91 Stockholm (Sweden); Rasmussen, J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Verdes-Montenegro, L. [Departamento Astronomía Extragaláctica, Instituto Astrofísica Andalucía (CSIC), Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Yun, M., E-mail: kalatalo@ipac.caltech.edu [University of Massachusetts, Astronomy Department, Amherst, MA 01003 (United States)

    2014-11-10

    We present [C II] and [O I] observations from Herschel and CO(1-0) maps from the Combined Array for Research in Millimeter Astronomy (CARMA) of the Hickson compact group HCG 57, focusing on the galaxies HCG 57a and HCG 57d. HCG 57a has been previously shown to contain enhanced quantities of warm molecular hydrogen consistent with shock or turbulent heating. Our observations show that HCG 57d has strong [C II] emission compared to L {sub FIR} and weak CO(1-0), while in HCG 57a, both the [C II] and CO(1-0) are strong. HCG 57a lies at the upper end of the normal distribution of the [C II]/CO and [C II]/FIR ratios, and its far-infrared (FIR) cooling supports a low-density, warm, diffuse gas that falls close to the boundary of acceptable models of a photon-dominated region. However, the power radiated in the [C II] and warm H{sub 2} emissions have similar magnitudes, as seen in other shock-dominated systems and predicted by recent models. We suggest that shock heating of the [C II] is a viable alternative to photoelectric heating in violently disturbed, diffuse gas. The existence of shocks is also consistent with the peculiar CO kinematics in the galaxy, indicating that highly noncircular motions are present. These kinematically disturbed CO regions also show evidence of suppressed star formation, falling a factor of 10-30 below normal galaxies on the Kennicutt-Schmidt relation. We suggest that the peculiar properties of both galaxies are consistent with a highly dissipative, off-center collisional encounter between HCG 57d and 57a, creating ring-like morphologies in both systems. Highly dissipative gas-on-gas collisions may be more common in dense groups because of the likelihood of repeated multiple encounters. The possibility of shock-induced star-formation suppression may explain why a subset of these HCG galaxies has been found previously to fall in the mid-infrared green valley.

  3. Far infrared conductivity of charge density wave materials and the oxygen isotope effect in high-T sub c superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Creager, W.N.

    1991-09-01

    The far infrared reflectance and conductivity of (Ta{sub 1-x}Nb{sub x}Se{sub 4}){sub 2}I and TaS{sub 3} have been measured to determine the origin of a huge infrared resonance that dominates the charge density wave (CDW) dynamics along with the pinned acoustic phason mode in the related materials (TaSe{sub 4}){sub 2}I and K{sub 0. 3}MoO{sub 3}. The measurements cover frequencies from 3 to 700cm{sup {minus}1} and the temperature range from 15K to 300K. In the niobium-doped alloys (Ta{sub 1-x}Nb{sub x}Se{sub 4}){sub 2}I, the size and frequency of the giant infrared mode remain nearly constant as the impurity concentration x is increased. For TaS{sub 3}, the pinned acoustic phason near 0.5cm{sup {minus}1} dominates {var epsilon}({omega}) and an additional small mode lies near 9cm{sup {minus}1}. The latter mode is much smaller than the infrared mode in other CDW materials. These results rule out several models of a generic infrared mode'' in CDW excitations. They are compared in detail to the predictions of a recent theory attributing the infrared mode to a bound collective mode localized at impurity sites within the crystal. The transmittance of K{sub 0.3}MoO{sub 3} has been measured at 1.2K with a strong dc electric field applied across the crystal. Under these conditions, the charge density wave depins abruptly and carries large currents with near-zero differential resistance. For some samples, the low-frequency transmittance is enhanced slightly when the CDW depins. The magnitude of the oxygen isotope effect in the high-{Tc} superconductor YBa{sub 2}Cu{sub 3}O{sub 7} has been determined by substitution of {sup 18}O for {sup 16}O. A series of cross-exchanges was performed on high-quality polycrystalline specimens to eliminate uncertainties due to sample heat treatments and sample inhomogeneities.

  4. A peculiar class of debris disks from Herschel/DUNES - A steep fall off in the far infrared

    CERN Document Server

    Ertel, S; Marshall, J P; Eiroa, C; Augereau, J -C; Krivov, A V; Loehne, T; Absil, O; Ardila, D; Arevalo, M; Bayo, A; Bryden, G; del Burgo, C; Greaves, J; Kennedy, G; Lebreton, J; Liseau, R; Maldonado, J; Montesinos, B; Mora, A; Pilbratt, G L; Sanz-Forcada, J; Stapelfeldt, K; White, G J

    2012-01-01

    Aims. We present photometric data of debris disks around HIP 103389 (HD 199260), HIP 107350 (HN Peg, HD206860), and HIP 114948 (HD 219482), obtained in the context of our Herschel Open Time Key Program DUNES (DUst around NEarby Stars). Methods. We used Herschel/PACS to detect the thermal emission of the three debris disks with a 3 sigma sensitivity of a few mJy at 100 um and 160 um. In addition, we obtained Herschel/PACS photometric data at 70 um for HIP 103389. Two different approaches are applied to reduce the Herschel data to investigate the impact of data reduction on the photometry. We fit analytical models to the available spectral energy distribution (SED) data. Results. The SEDs of the three disks potentially exhibit an unusually steep decrease at wavelengths > 70 um. We investigate the significance of the peculiar shape of these SEDs and the impact on models of the disks provided it is real. Our modeling reveals that such a steep decrease of the SEDs in the long wavelength regime is inconsistent with...

  5. A numerical study of time-dependent Schrödinger equation for multiphoton vibrational interaction of NO molecule, modelled as Morse oscillator, with intense far-infrared femtosecond lasers

    Indian Academy of Sciences (India)

    Amita Wadehra; B M Deb

    2003-10-01

    For the NO molecule, modelled as a Morse oscillator, time-dependent (TD) nuclear Schrödinger equation has been numerically solved for the multiphoton vibrational dynamics of the molecule under a far-infrared laser of wavelength 10503 nm, and four different intensities, = 1 × 108, 1 × 1013, 5 × 1016, and 5 × 1018W cm-2 respectively. Starting from the vibrational ground state at zero time, various TD quantities such as the norm, dissociation probability, potential energy curve and dipole moment are examined. Rich high-harmonics generation (HHG) spectra and above-threshold dissociation (ATD) spectra, due to the multiphoton interaction of vibrational motions with the laser field, and consequent elevation to the vibrational continuum, have been obtained and analysed.

  6. An Ultraviolet-to-Radio Broadband Spectral Atlas of Nearby Galaxies

    CERN Document Server

    Dale, D A; Gordon, K D; Hanson, H M; Armus, L; Bendo, G J; Bianchi, L; Block, M; Boissier, S; Boselli, A; Buckalew, B A; Buat, V; Burgarella, D; Calzetti, D; Cannon, J M; Engelbracht, C W; Helou, G; Hollenbach, D J; Jarrett, T H; Kennicutt, R C; Leitherer, C; Li, A; Madore, B F; Meyer, M J; Murphy, E J; Regan, M W; Roussel, H; Smith, J D T; Sosey, M L; Thilker, D A; Walter, F

    2006-01-01

    The ultraviolet-to-radio continuum spectral energy distributions are presented for all 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). A principal component analysis of the sample shows that most of the sample's spectral variations stem from two underlying components, one representative of a galaxy with a low infrared-to-ultraviolet ratio and one representative of a galaxy with a high infrared-to-ultraviolet ratio. The influence of several parameters on the infrared-to-ultraviolet ratio is studied (e.g., optical morphology, disk inclination, far-infrared color, ultraviolet spectral slope, and star formation history). Consistent with our understanding of normal star-forming galaxies, the SINGS sample of galaxies in comparison to more actively star-forming galaxies exhibits a larger dispersion in the infrared-to-ultraviolet versus ultraviolet spectral slope correlation. Early type galaxies, exhibiting low star formation rates and high optical surface brightnesses, have the most discrepant in...

  7. The Spectral Energy Distribution of the Coldest Known Brown Dwarf

    CERN Document Server

    Luhman, K L

    2016-01-01

    WISE J085510.83-071442.5 (hereafter WISE 0855-0714) is the coldest known brown dwarf (~250 K) and the fourth closest known system to the Sun (2.2 pc). It has been previously detected only in the J band and two mid-IR bands. To better measure its spectral energy distribution (SED), we have performed deep imaging of WISE 0855-0714 in six optical and near-IR bands with Gemini Observatory, the Very Large Telescope, and the Hubble Space Telescope. Five of the bands show detections, although one detection is marginal (S/N~3). We also have obtained two epochs of images with the Spitzer Space Telescope for use in refining the parallax of the brown dwarf. By combining astrometry from this work and previous studies, we have derived a parallax of 0.449+/-0.008" (2.23+/-0.04 pc). We have compared our photometry for WISE 0855-0714 to data for known Y dwarfs and to the predictions of three suites of models by Saumon et al. (2012) and Morley et al. (2012, 2014) that are defined by the presence or absence of clouds and non-e...

  8. Energy and Spectral Efficiency of Very Large Multiuser MIMO Systems

    CERN Document Server

    Ngo, Hien Quoc; Marzetta, Thomas L

    2011-01-01

    A multiplicity of autonomous terminals simultaneously transmits data streams to a compact array of antennas. The array uses imperfect channel-state information derived from transmitted pilots to extract the individual data streams. The power radiated by the terminals can be made inversely proportional to the square-root of the number of base station antennas with no reduction in performance. In contrast if perfect channel-state information were available the power could be made inversely proportional to the number of antennas. Lower capacity bounds for maximum-ratio combining (MRC), zero-forcing (ZF) and minimum mean-square error (MMSE) detection are derived. A MRC receiver normally performs worse than ZF and MMSE. However as power levels are reduced, the cross-talk introduced by the inferior maximum-ratio receiver eventually falls below the noise level and this simple receiver becomes a viable option. The tradeoff between the energy efficiency (as measured in bits/J) and spectral efficiency (as measured in b...

  9. Modelling and interpreting spectral energy distributions of galaxies with BEAGLE

    CERN Document Server

    Chevallard, Jacopo

    2016-01-01

    We present a new-generation tool to model and interpret spectral energy distributions (SEDs) of galaxies, which incorporates in a consistent way the production of radiation and its transfer through the interstellar and intergalactic media. This flexible tool, named BEAGLE (for BayEsian Analysis of GaLaxy sEds), allows one to build mock galaxy catalogues as well as to interpret in terms of physical parameters any combination of photometric and spectroscopic galaxy observations. The current version of the tool includes the versatile modeling of the emission from stars and photoionized gas, attenuation by dust and the accounting for different instrumental effects. We show a first application of the BEAGLE tool to the interpretation of broadband SEDs of a published sample of ${\\sim}10^4$ galaxies at redshifts $0.1 \\lesssim z\\lesssim8$. We find that the constraints derived on photometric redshifts using this multi-purpose tool are comparable to those obtained using public, dedicated photometric-redshift codes and ...

  10. Water in star forming regions with Herschel (WISH) III. Far-infrared cooling lines in low-mass young stellar objects

    CERN Document Server

    Karska, A; van Dishoeck, E F; Wampfler, S F; Kristensen, L E; Goicoechea, J R; Visser, R; Nisini, B; Garcia, I San-Jose; Bruderer, S; Sniady, P; Doty, S; Fedele, D; Yildiz, U A; Benz, A O; Bergin, E; Caselli, P; Herpin, F; Hogerheijde, M R; Johnstone, D; Jorgensen, J K; Liseau, R; Tafalla, M; van der Tak, F; Wyrowski, F

    2013-01-01

    (Abridged) Far-infrared Herschel-PACS spectra of 18 low-mass protostars of various luminosities and evolutionary stages are studied. We quantify their far-infrared line emission and the contribution of different atomic and molecular species to the gas cooling budget during protostellar evolution. We also determine the spatial extent of the emission and investigate the underlying excitation conditions. Most of the protostars in our sample show strong atomic and molecular far-infrared emission. Water is detected in 17 objects, including 5 Class I sources. The high-excitation H2O line at 63.3 micron is detected in 7 sources. CO transitions from J=14-13 up to 49-48 are found and show two distinct temperature components on Boltzmann diagrams with rotational temperatures of ~350 K and ~700 K. H2O has typical excitation temperatures of ~150 K. Emission from both Class 0 and I sources is usually spatially extended along the outflow direction but with a pattern depending on the species and the transition. The H2O line...

  11. MEAN SPECTRAL ENERGY DISTRIBUTIONS AND BOLOMETRIC CORRECTIONS FOR LUMINOUS QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Krawczyk, Coleman M.; Richards, Gordon T.; Mehta, Sajjan S.; Vogeley, Michael S. [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Gallagher, S. C. [Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7 (Canada); Leighly, Karen M. [Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States); Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

    2013-05-01

    We explore the mid-infrared (mid-IR) through ultraviolet (UV) spectral energy distributions (SEDs) of 119,652 luminous broad-lined quasars with 0.064 < z < 5.46 using mid-IR data from Spitzer and WISE, near-infrared data from the Two Micron All Sky Survey and UKIDSS, optical data from the Sloan Digital Sky Survey, and UV data from the Galaxy Evolution Explorer. The mean SED requires a bolometric correction (relative to 2500 A) of BC{sub 2500A} =2.75 {+-} 0.40 using the integrated light from 1 {mu}m-2 keV, and we further explore the range of bolometric corrections exhibited by individual objects. In addition, we investigate the dependence of the mean SED on various parameters, particularly the UV luminosity for quasars with 0.5 {approx}< z {approx}< 3 and the properties of the UV emission lines for quasars with z {approx}> 1.6; the latter is a possible indicator of the strength of the accretion disk wind, which is expected to be SED-dependent. Luminosity-dependent mean SEDs show that, relative to the high-luminosity SED, low-luminosity SEDs exhibit a harder (bluer) far-UV spectral slope ({alpha}{sub UV}), a redder optical continuum, and less hot dust. Mean SEDs constructed instead as a function of UV emission line properties reveal changes that are consistent with known Principal Component Analysis trends. A potentially important contribution to the bolometric correction is the unseen extreme UV (EUV) continuum. Our work suggests that lower-luminosity quasars and/or quasars with disk-dominated broad emission lines may require an extra continuum component in the EUV that is not present (or much weaker) in high-luminosity quasars with strong accretion disk winds. As such, we consider four possible models and explore the resulting bolometric corrections. Understanding these various SED-dependent effects will be important for accurate determination of quasar accretion rates.

  12. Energy Content & Spectral Energy Representation of Wave Propagation in a Granular Chain

    Science.gov (United States)

    Shrivastava, Rohit; Luding, Stefan

    2017-04-01

    A mechanical wave is propagation of vibration with transfer of energy and momentum. Studying the energy as well as spectral energy characteristics of a propagating wave through disordered granular media can assist in understanding the overall properties of wave propagation through materials like soil. The study of these properties is aimed at modeling wave propagation for oil, mineral or gas exploration (seismic prospecting) or non-destructive testing for the study of internal structure of solids. Wave propagation through granular materials is often accompanied by energy attenuation which is quantified by Quality factor and this parameter has often been used to characterize material properties, hence, determining the Quality factor (energy attenuation parameter) can also help in determining the properties of the material [3], studied experimentally in [2]. The study of Energy content (Kinetic, Potential and Total Energy) of a pulse propagating through an idealized one-dimensional discrete particle system like a mass disordered granular chain can assist in understanding the energy attenuation due to disorder as a function of propagation distance. The spectral analysis of the energy signal can assist in understanding dispersion as well as attenuation due to scattering in different frequencies (scattering attenuation). The selection of one-dimensional granular chain also helps in studying only the P-wave attributes of the wave and removing the influence of shear or rotational waves. Granular chains with different mass distributions have been studied, by randomly selecting masses from normal, binary and uniform distributions and the standard deviation of the distribution is considered as the disorder parameter, higher standard deviation means higher disorder and lower standard deviation means lower disorder [1]. For obtaining macroscopic/continuum properties, ensemble averaging has been invoked. Instead of analyzing deformation-, velocity- or stress

  13. MicroRNA-134 Contributes to Glucose-Induced Endothelial Cell Dysfunction and This Effect Can Be Reversed by Far-Infrared Irradiation.

    Directory of Open Access Journals (Sweden)

    Hsei-Wei Wang

    Full Text Available Diabetes mellitus (DM is a metabolic disease that is increasing worldwide. Furthermore, it is associated with the deregulation of vascular-related functions, which can develop into major complications among DM patients. Endothelial colony forming cells (ECFCs have the potential to bring about medical repairs because of their post-natal angiogenic activities; however, such activities are impaired by high glucose- (HG and the DM-associated conditions. Far-infrared radiation (FIR transfers energy as heat that is perceived by the thermoreceptors in human skin. Several studies have revealed that FIR improves vascular endothelial functioning and boost angiogenesis. FIR has been used as anti-inflammatory therapy and as a clinical treatment for peripheral circulation improvement. In addition to vascular repair, there is increasing evidence to show that FIR can be applied to a variety of diseases, including cardiovascular disorders, hypertension and arthritis. Yet mechanism of action of FIR and the biomarkers that indicate FIR effects remain unclear. MicroRNA-134 (miR-134-5p was identified by small RNA sequencing as being increased in high glucose (HG treated dfECFCs (HG-dfECFCs. Highly expressed miR-134 was also validated in dmECFCs by RT-qPCR and it is associated with impaired angiogenic activities of ECFCs. The functioning of ECFCs is improved by FIR treatment and this occurs via a reduction in the level of miR-134 and an increase in the NRIP1 transcript, a direct target of miR-134. Using a mouse ischemic hindlimb model, the recovery of impaired blood flow in the presence of HG-dfECFCs was improved by FIR pretreatment and this enhanced functionality was decreased when there was miR-134 overexpression in the FIR pretreated HG-dfECFCs. In conclusion, our results reveal that the deregulation of miR-134 is involved in angiogenic defects found in DM patients. FIR treatment improves the angiogenic activity of HG-dfECFCs and dmECFCs and FIR has potential as

  14. The spectral energy distribution and mass-loss history of IRC+10420

    NARCIS (Netherlands)

    Oudmaijer, RD; Matthews, HE; Blommaert, JADL; Sahu, KC

    1996-01-01

    We present a study of the spectral energy distribution of the peculiar hypergiant IRC + 10420. To this end we have collected published photometry of IRC + 10420 and obtained some new data, in order to construct the spectral energy distribution and fit it with a radiative transfer model. In addition

  15. Bayesian fitting of Taurus brown dwarf spectral energy distributions

    Science.gov (United States)

    Mayne, N. J.; Harries, Tim J.; Rowe, John; Acreman, David M.

    2012-06-01

    We present derived stellar and disc parameters for a sample of Taurus brown dwarfs both with and without evidence of an associated disc. These parameters have been derived using an online fitting tool (), which includes a statistically robust derivation of uncertainties, an indication of parameter degeneracies and a complete treatment of the input photometric and spectroscopic observations. The observations of the Taurus members with indications of disc presence have been fitted using a grid of theoretical models including detailed treatments of physical processes accepted for higher mass stars, such as dust sublimation, and a simple treatment of the accretion flux. This grid of models has been designed to test the validity of the adopted physical mechanisms, but we have also constructed models using parametrization, for example semi-empirical dust sublimation radii, for users solely interested in parameter derivation and the quality of the fit. The parameters derived for the naked and disc brown dwarf systems are largely consistent with literature observations. However, our inner disc edge locations are consistently closer to the star than previous results and we also derive elevated accretion rates over non-spectral energy distribution based accretion rate derivations. For inner edge locations, we attribute these differences to the detailed modelling we have performed of the disc structure, particularly at the crucial inner edge where departures in geometry from the often adopted vertical wall due to dust sublimation (and therefore accretion flux) can compensate for temperature (and therefore distance) changes to the inner edge of the dust disc. In the case of the elevated derived accretion rates, in some cases, this may be caused by the intrinsic stellar luminosities of the targets exceeding that predicted by the isochrones we have adopted.

  16. Modelling and interpreting spectral energy distributions of galaxies with BEAGLE

    Science.gov (United States)

    Chevallard, Jacopo; Charlot, Stéphane

    2016-10-01

    We present a new-generation tool to model and interpret spectral energy distributions (SEDs) of galaxies, which incorporates in a consistent way the production of radiation and its transfer through the interstellar and intergalactic media. This flexible tool, named BEAGLE (for BayEsian Analysis of GaLaxy sEds), allows one to build mock galaxy catalogues as well as to interpret any combination of photometric and spectroscopic galaxy observations in terms of physical parameters. The current version of the tool includes versatile modelling of the emission from stars and photoionized gas, attenuation by dust and accounting for different instrumental effects, such as spectroscopic flux calibration and line spread function. We show a first application of the BEAGLE tool to the interpretation of broad-band SEDs of a published sample of ˜ 10^4 galaxies at redshifts 0.1 ≲ z ≲ 8. We find that the constraints derived on photometric redshifts using this multipurpose tool are comparable to those obtained using public, dedicated photometric-redshift codes and quantify this result in a rigorous statistical way. We also show how the post-processing of BEAGLE output data with the PYTHON extension PYP-BEAGLE allows the characterization of systematic deviations between models and observations, in particular through posterior predictive checks. The modular design of the BEAGLE tool allows easy extensions to incorporate, for example, the absorption by neutral galactic and circumgalactic gas, and the emission from an active galactic nucleus, dust and shock-ionized gas. Information about public releases of the BEAGLE tool will be maintained on http://www.jacopochevallard.org/beagle.

  17. The Spectral Energy Distribution of the Coldest Known Brown Dwarf

    Science.gov (United States)

    Luhman, K. L.; Esplin, T. L.

    2016-09-01

    WISE J085510.83-071442.5 (hereafter WISE 0855-0714) is the coldest known brown dwarf (˜250 K) and the fourth-closest known system to the Sun (2.2 pc). It has been previously detected only in the J band and two mid-IR bands. To better measure its spectral energy distribution (SED), we have performed deep imaging of WISE 0855-0714 in six optical and near-IR bands with Gemini Observatory, the Very Large Telescope, and the Hubble Space Telescope. Five of the bands show detections, although one detection is marginal (S/N ˜ 3). We also have obtained two epochs of images with the Spitzer Space Telescope for use in refining the parallax of the brown dwarf. By combining astrometry from this work and previous studies, we have derived a parallax of 0.449 ± 0.008″ (2.23 ± 0.04 pc). We have compared our photometry for WISE 0855-0714 to data for known Y dwarfs and to the predictions of three suites of models by Saumon et al. and Morley et al. that are defined by the presence or absence of clouds and nonequilibrium chemistry. Our estimates of Y - J and J - H for WISE 0855-0714 are redder than colors of other Y dwarfs, confirming a predicted reversal of near-IR colors to redder values at temperatures below 300-400 K. In color-magnitude diagrams, no single suite of models provides a clearly superior match to the sequence formed by WISE 0855-0714 and other Y dwarfs. Instead, the best-fitting model changes from one diagram to the next. Similarly, all of the models have substantial differences from the SED of WISE 0855-0714. As a result, we are currently unable to constrain the presence of clouds or nonequilibrium chemistry in its atmosphere. Based on observations made with the Spitzer Space Telescope, the NASA/ESA Hubble Space Telescope, Gemini Observatory, and the ESO Telescopes at Paranal Observatory.

  18. Determination of the pigments present in a wallpaper of the middle nineteenth century: the combination of mid-diffuse reflectance and far infrared spectroscopies.

    Science.gov (United States)

    Arrizabalaga, Iker; Gómez-Laserna, Olivia; Aramendia, Julene; Arana, Gorka; Madariaga, Juan Manuel

    2014-04-24

    In this work the determination of the pigments present in a decorative wallpaper of the middle nineteenth century from the Santa Isabel factory (Vitoria-Gasteiz, Basque Country, Spain) has been performed by a combination of mid-Diffuse Reflectance Infrared Spectroscopy (DRIFT) and Far Infrared Spectroscopy (FIR) in transmission mode. The DRIFT is a powerful infrared technique that is not widely used in the analyses of artworks in spite of being especially adequate for powdered samples. In this mode, sample pretreatment is not required and the obtained spectra are easier to solve than those obtained in transmittance mode. Those pigments which are not active in the mid-infrared region may be determined easily by FIR. In the last decade, in the field of painted materials very few studies performed by far infrared spectroscopy and mid infrared spectroscopy in diffuse reflectance mode can be found. In most of them the researchers have used one of these techniques, but in no case the combination of both. As we demonstrate in this work, combining these two techniques a complete characterization of the wallpaper can be carried out. Small samples were collected from the wallpaper for the analysis of the rose, brown, yellow and blue colours. In this way, minium (Pb3O4), calcite (CaCO3), barium sulphate (BaSO4), prussian blue (Fe7C18N18), iron oxide yellow (α-FeOOH), vermillion (HgS) and carbon black pigment from organic origen were detected. Finally, the validation was carried out by XRF and Raman spectroscopy getting the same results as with the combination of diffuse reflectance infrared spectroscopy and far infrared spectroscopy.

  19. Gender-Related Effect in Oxygenation Dynamics by Using Far-Infrared Intervention with Near-Infrared Spectroscopy Measurement: A Gender Differences Controlled Trial.

    Directory of Open Access Journals (Sweden)

    Wei-Lung Kao

    Full Text Available Many studies have indicated the microcirculation can directly respond to disease-related symptoms. However, the capacity of microcirculation would vary due to the gender differences. Near-infrared spectroscopy (NIRS is a noninvasive technique to monitor tissue oxygenation dynamics. In this study, the far-infrared (FIR source was used for physiological intervention of microcirculation. The experimental results show that the nature difference of oxygenation status exists between male and female during FIR irradiation. Therefore, we suggest the NIRS-based assessment should be calibrated with the gender-related effect for clinical diagnosis of peripheral arterial disease.

  20. Far-infrared conductivity measurements of pair breaking in superconducting Nb 0.5 Ti 0.5 N thin films induced by an external magnetic field.

    Science.gov (United States)

    Xi, Xiaoxiang; Hwang, J; Martin, C; Tanner, D B; Carr, G L

    2010-12-17

    We report the complex optical conductivity of a superconducting thin film of Nb 0.5 Ti 0.5 N in an external magnetic field. The field was applied parallel to the film surface and the conductivity extracted from far-infrared transmission and reflection measurements. The real part shows the superconducting gap, which we observe to be suppressed by the applied magnetic field. We compare our results with the pair-breaking theory of Abrikosov and Gor'kov and confirm directly the theory's validity for the optical conductivity.

  1. Far-infrared and submillimeter survey of the galactic plane from l = 11.5 deg to l = 17.5 deg

    Science.gov (United States)

    Campbell, M. F.; Niles, D. W.; Silverberg, R. F.; Hauser, M. G.; Stier, M. T.; Kelsall, T.; Hoffmann, W. F.; Thronson, H. A., Jr.

    1984-01-01

    Medium resolution (11 min) maps of the galactic plane are presented from l = 11.5 deg to l = 17.5 deg at wavelengths of 93 microns, 154 microns, and 190 microns. The maps are interpreted in terms of the temperature and spatial structure of diffuse far-infrared/submillimeter sources associated with evolved H II regions and a continuous ridge of galactic emission. The emission regions are found to be more extended at the longer wavelengths which implies that there must be a range of dust temperatures in the sources. The properties of the galactic ridge are similar to those of the sources.

  2. Preparation method of Ce{sub 1-x}Zr{sub x}O{sub 2}/tourmaline nanocomposite with high far-infrared emissivity and its mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Bin; Li, Wenlong [Chinese Academy of Sciences, State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics, Xi' an (China); University of Chinese Academy of Sciences, Beijing (China); Yang, Liqing; Wang, Haojing; Zhang, Hong [Chinese Academy of Sciences, State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics, Xi' an (China)

    2016-02-15

    Far-infrared functional nanocomposites were prepared by the coprecipitation method using natural tourmaline (XY{sub 3}Z{sub 6}Si{sub 6}O{sub 18}(BO{sub 3}){sub 3}V{sub 3}W, where X is Na{sup +}, Ca{sup 2+}, K{sup +}, or vacancy; Y is Mg{sup 2+}, Fe{sup 2+}, Mn{sup 2+}, Al{sup 3+}, Fe{sup 3+}, Mn{sup 3+}, Cr{sup 3+}, Li{sup +}, or Ti{sup 4+}; Z is Al{sup 3+}, Mg{sup 2+}, Cr{sup 3+}, or V{sup 3+}; V is O{sup 2-}, OH{sup -}; and W is O{sup 2-}, OH{sup -}, or F{sup -}) powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that Ce-Zr can further enhance the far-infrared emission properties of tourmaline than Ce alone. Through characterization by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), the mechanism by which Ce(-Zr) acts on the far-infrared emission property of tourmaline was systematically studied. The XPS spectra show that the Fe{sup 3+} ratio inside tourmaline powders after heat treatment can be raised by doping Ce and further raised after adding Zr. Moreover, it is showed that Ce{sup 3+} is dominant inside the samples, but its dominance is replaced by Ce{sup 4+} outside. In addition, XRD results indicate the formation of CeO{sub 2} and Ce{sub 1-x}Zr{sub x}O{sub 2} crystallites during the heat treatment, and further, TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce-Zr-doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of Fe{sup 2+} (0.074 nm in radius) to Fe{sup 3+} (0.064 nm in radius) inside the tourmaline caused by Zr enhancing the redox shift between Ce{sup 4+} and Ce{sup 3+} via improving the

  3. Far-infrared electroluminescence characteristics of an InGaP/InGaAs/Ge triple-junction solar cell under forward DC bias

    Institute of Scientific and Technical Information of China (English)

    Xiao Wenbo; He Xingdao; Gao Yiqing; Zhang Zhimin; Liu Jiangtao

    2012-01-01

    The far-infrared electroluminescence characteristics of an InGaP/InGaAs/Ge solar cell are investigated under forward DC bias at room temperature in dark conditions.An electroluminescence viewgraph shows the clear device structures,and the electroluminescence intensity is shown to increases exponentially with bias voltage and linearly with bias current.The results can be interpreted using an equivalent circuit of a single ideal diode model for triple-junction solar cells.The good fit between the measured and calculated data proves the above conclusions.This work is of guiding significance for current solar cell testing and research.

  4. Cosmic Ray Spectral Deformation Caused by Energy Determination Errors

    CERN Document Server

    Carlson, Per J; Carlson, Per; Wannemark, Conny

    2005-01-01

    Using simulation methods, distortion effects on energy spectra caused by errors in the energy determination have been investigated. For cosmic ray proton spectra, falling steeply with kinetic energy E as E-2.7, significant effects appear. When magnetic spectrometers are used to determine the energy, the relative error increases linearly with the energy and distortions with a sinusoidal form appear starting at an energy that depends significantly on the error distribution but at an energy lower than that corresponding to the Maximum Detectable Rigidity of the spectrometer. The effect should be taken into consideration when comparing data from different experiments, often having different error distributions.

  5. Far-infrared spectroscopy of Zn{sub 1−x}Mn{sub x}GeAs{sub 2} single crystals: Plasma damping influence on plasmon – Phonon interaction

    Energy Technology Data Exchange (ETDEWEB)

    Romcevic, N., E-mail: romcevi@ipb.ac.rs [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Romcevic, M. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Dobrowolski, W.D.; Kilanski, L. [Institute of Physics, Polish Academy of Science, 02-668 Warsaw (Poland); Petrovic, M.; Trajic, J.; Hadzic, B.; Lazarevic, Z.; Gilic, M.; Ristic-Djurovic, J.L.; Paunovic, N. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Reszka, A.; Kowalski, B.J. [Institute of Physics, Polish Academy of Science, 02-668 Warsaw (Poland); Fedorchenko, I.V.; Marenkin, S.F. [Kurnakov Institute of General and Inorganic Chemistry RAS, 119991 Moscow (Russian Federation); National Institute of Science and Technology, MISiS, Moscow (Russian Federation)

    2015-11-15

    The interest in thorough description of Zn{sub 1–x}Mn{sub x}GeAs{sub 2} arises from its suitability for application in the field of non-linear optics. The room temperature far-infrared reflectivity spectra of single crystals Zn{sub 1–x}Mn{sub x}GeAs{sub 2}, where 0 ≤ x ≤ 0.078, were measured in the spectral range from 80 cm{sup −1} to 500 cm{sup −1}. The spectra were analyzed by fitting procedure using a dielectric function which includes interaction between a plasmon and two different phonons. The detected phonons are in excellent agreement with the theoretical predictions. The MnAs cluster phonons are detected, as well. - Highlights: • Zn{sub 1−x}Mn{sub x}GeAs{sub 2} samples were grown using a direct fusion method. • Differencies between plasmon-phonon and plasmon-two different phonon interaction were discussed. • Plasmon damping influence on plasmon – (two) phonon interaction was registered. • MnAs clusters phonons are detected.

  6. SPECTRAL-WEIGHT TRANSFER - BREAKDOWN OF LOW-ENERGY-SCALE SUM-RULES IN CORRELATED SYSTEMS

    NARCIS (Netherlands)

    MEINDERS, MBJ; ESKES, H; SAWATZKY, GA

    1993-01-01

    In this paper we study the spectral-weight transfer from the high- to the low-energy scale by means of exact diagonalization of finite clusters for the Mott-Hubbard and charge-transfer model. We find that the spectral-weight transfer is very sensitive to the hybridization strength as well as to the

  7. X-ray emission around the z=4.1 radio galaxy TNJ1338-1942 and the potential role of far-infrared photons in AGN Feedback

    CERN Document Server

    Smail, Ian

    2013-01-01

    We report the discovery in an 80-ks observation of spatially-extended X-ray emission around the high-redshift radio galaxy TNJ1388-1942 (z=4.11) with the Chandra X-ray Observatory. The X-ray emission extends over a ~30-kpc diameter region and although it is less extended than the GHz-radio lobes, it is roughly aligned with them. We suggest that the X-ray emission arises from Inverse Compton (IC) scattering of photons by relativistic electrons around the radio galaxy. At z=4.11 this is the highest redshift detection of IC emission around a radio galaxy. We investigate the hypothesis that in this compact source, the Cosmic Microwave Background (CMB), which is ~700x more intense than at z~0 is nonetheless not the relevant seed photon field for the bulk of the IC emission. Instead, we find a tentative correlation between the IC emission and far-infrared luminosities of compact, far-infrared luminous high-redshift radio galaxies (those with lobe lengths of <100kpc). Based on these results we suggest that in the...

  8. Comfort and Functional Properties of Far-Infrared/Anion-Releasing Warp-Knitted Elastic Composite Fabrics Using Bamboo Charcoal, Copper, and Phase Change Materials

    Directory of Open Access Journals (Sweden)

    Ting-Ting Li

    2016-02-01

    Full Text Available Elastic warp-knitted composite fabrics with far-infrared emissivity and an anion-releasing property were prepared using bamboo charcoal (BC, copper (Cu, and phase-change material (PCM. The functional composite fabric, which was composed of self-made complex yarns with various twisting degrees and material composition, were created using a rotor twister and ring-spinning technique. The fabric structure was diversified by the feeding modes of weft yarn into a crochet-knitting machine. The twist number of complex yarns was optimized by tensile tenacity, twist contraction, and hairiness, and analysis showed that twisting at 12 twists per inch produced the highest tensile tenacity and appropriate twist contraction and hairiness. Comfort evaluation showed that the elastic composite fabrics with BC weft yarns exhibited higher water–vapor transmission rate and air permeability, reaching 876 g/m2∙ day and 73.2 cm3/s/cm2, respectively. Three structures of composite fabric with various weft yarns had >0.85 ε far-infrared emissivity and 350–420 counts/cm3 anion amount. The prepared elastic warp-knitted fabrics can provide a comfortable, dry, and breathable environment to the wearer and can thus be applied as health-care textiles in the future.

  9. Rest-frame Optical Emission Lines in Far-Infrared Selected Galaxies at z<1.7 from the FMOS-COSMOS Survey

    CERN Document Server

    Kartaltepe, Jeyhan S; Silverman, J D; Kashino, D; Chu, J; Zahid, H; Hasinger, G; Kewley, L; Matsuoka, K; Nagao, T; Riguccini, L; Salvato, M; Schawinski, K; Taniguchi, Y; Treister, E; Capak, P; Daddi, E; Ohta, K

    2015-01-01

    We have used FMOS on Subaru to obtain near-infrared spectroscopy of 123 far-infrared selected galaxies in COSMOS and obtain the key rest-frame optical emission lines. This is the largest sample of infrared galaxies with near-infrared spectroscopy at these redshifts. The far-infrared selection results in a sample of galaxies that are massive systems that span a range of metallicities in comparison with previous optically selected surveys, and thus has a higher AGN fraction and better samples the AGN branch. We establish the presence of AGN and starbursts in this sample of (U)LIRGs selected as Herschel-PACS and Spitzer-MIPS detections in two redshift bins (z~0.7 and z~1.5) and test the redshift dependence of diagnostics used to separate AGN from star-formation dominated galaxies. In addition, we construct a low redshift (z~0.1) comparison sample of infrared selected galaxies and find that the evolution from z~1.5 to today is consistent with an evolving AGN selection line and a range of ISM conditions and metall...

  10. DISCOVERY OF TIME VARIATION OF THE INTENSITY OF MOLECULAR LINES IN IRC+10216 IN THE SUBMILLIMETER AND FAR-INFRARED DOMAINS

    Energy Technology Data Exchange (ETDEWEB)

    Cernicharo, J.; Quintana-Lacaci, G.; Agúndez, M.; Velilla-Prieto, L. [Group of Molecular Astrophysics, ICMM, CSIC, C/Sor Juana Inés de La Cruz N3, E-28049 Madrid (Spain); Teyssier, D.; García-Lario, P. [ESA, ESAC, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid (Spain); Daniel, F. [Univ. Grenoble Alpes, IPAG, F-38000 Grenoble (France); Decin, L. [Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Guélin, M. [Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406 St-Martin d' Hères (France); Encrenaz, P. [LERMA, Observatoire de Paris, 61 Av. de l' Observatoire, F-75014 Paris (France); De Beck, E. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE 439 92 Onsala (Sweden); Barlow, M. J. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Groenewegen, M. A. T. [Koninklijke Sterrenwacht van België, Ringlaan 3, B-1180 Brussels (Belgium); Neufeld, D. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Pearson, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2014-11-20

    We report on the discovery of strong intensity variations in the high rotational lines of abundant molecular species toward the archetypical circumstellar envelope of IRC+10216. The observations have been carried out with the Heterodyne Instrument for the Far-Infrared (HIFI) instrument on board Herschel and with the IRAM30 m telescope. They cover several observing periods spreading over three years. The line intensity variations for molecules produced in the external layers of the envelope most likely result from time variations in the infrared pumping rates. We analyze the main implications this discovery has on the interpretation of molecular line emission in the envelopes of Mira-type stars. Radiative transfer calculations must take into account both the time variability of infrared pumping and the possible variation of the dust and gas temperatures with stellar phase in order to reproduce the observation of molecular lines at different epochs. The effect of gas temperature variations with stellar phase could be particularly important for lines produced in the innermost regions of the envelope. Each layer of the circumstellar envelope sees the stellar light radiation with a different lag time (phase). Our results show that this effect must be included in the models. The submillimeter and far infrared lines of asymptotic giant branch stars can no longer be considered as safe intensity calibrators.

  11. Are quiescent galaxies truly devoid of star formation? The mid-, far-infrared and radio properties of quiescent galaxies at z = 0.1 - 3

    Science.gov (United States)

    Man, Allison W. S.

    Quiescent galaxy candidates are typically identified by their low unobscured star formation rates from deep field photometric surveys. However, their selection technique relies on the assumption of a universal dust attenuation curve. It is important to verify the selection through independent SFR indicators at longer wavelengths. Current mid-, far-infrared and radio surveys are limited to detecting only galaxies with very strong star formation or AGN activity. Here, I present the first comprehensive stacking results across mid-, far-infrared and radio wavelengths using Spitzer, Herschel and VLA data in the COSMOS field (Man et al. 2014). We find that the rest-frame NUV-r and r-J color criteria, combined with low 24 μm emission, provides a robust selection of truly quiescent galaxies out to z = 3. Additionally, we find evidence of radio emission in excess of the expected total star formation in quiescent galaxies at z ~ 0-1.5, indicative of a ubiquitous presence of low-luminosity radio AGN among them.

  12. Electron-energy-loss spectral library and its application to materials science

    Energy Technology Data Exchange (ETDEWEB)

    Zaluzec, N.J.

    1983-09-01

    An electron energy loss spectral library can be an invaluable tool in materials research from a fundamental as well as a practical standpoint. Although it will not alleviate all the complications associated with quantification, this type of library can help to elucidate details of spectral profiles previously found intractable. This work was supported by the US Department of Energy. The author also wishes to express his gratitude to the organizing committee for partial financial support provided to attend this meeting.

  13. Spectrally and Energy Efficient OFDM (SEE-OFDM) for Intensity Modulated Optical Wireless Systems

    OpenAIRE

    Lam, Emily; Wilson, Sarah Kate; Elgala, Hany; Little, Thomas D. C.

    2015-01-01

    Spectrally and energy efficient orthogonal frequency division multiplexing (SEE-OFDM) is an optical OFDM technique based on combining multiple asymmetrically clipped optical OFDM (ACO-OFDM) signals into one OFDM signal. By summing different components together, SEE-OFDM can achieve the same spectral efficiency as DC-biased optical OFDM (DCO-OFDM) without an energy-inefficient DC-bias. This paper introduces multiple methods for decoding a SEE-OFDM symbol and shows that an iterative decoder wit...

  14. MgB2 Thin-Film Bolometer for Applications in Far-Infrared Instruments on Future Planetary Missions

    Science.gov (United States)

    Lakew, B.; Aslam, S.; Brasunas, J.; Cao, N.; Costen, N.; La, A.; Stevenson, T.; Waczynski, A.

    2012-01-01

    A SiN membrane based MgB2 thin-film bolometer, with a non-optimized absorber, has been fabricated that shows an electrical noise equivalent power of 256 fW/square root Hz operating at 30 Hz in the 8.5 - 12.35 micron spectral bandpass. This value corresponds to an electrical specific detectivity of 7.6 x 10(exp 10) cm square root Hz/W. The bolometer shows a measured blackbody (optical) specific detectivity of 8.8 x 10(exp 9) cm square root Hz/W, with a responsivity of 701.5 kV/W and a first-order time constant of 5.2 ms. It is predicted that with the inclusion of a gold black absorber that a blackbody specific detectivity of 6.4 x 10(exp 10) cm/square root Hz/W at an operational frequency of 10 Hz, can be realized for integration into future planetary exploration instrumentation where high sensitivity is required in the 17 - 250 micron spectral wavelength range.

  15. A Spitzer Space Telescope far-infrared spectral atlas of compact sources in the Magellanic Clouds. II. The Small Magellanic Cloud

    CERN Document Server

    van Loon, Jacco Th; Gordon, Karl D; Sloan, G C; Engelbracht, C W

    2010-01-01

    We present 52-93 micron spectra, obtained with the Spitzer Space Telescope, of luminous compact far-IR sources in the SMC. These comprise 9 Young Stellar Objects (YSOs), the compact HII region N81 and a similar object within N84, and two red supergiants (RSGs). The spectra of the sources in N81 (of which we also show the ISO-LWS spectrum between 50-170 micron) and N84 both display strong [OI] 63-micron and [OIII] 88-micron fine-structure line emission. We attribute these lines to strong shocks and photo-ionized gas, respectively, in a ``champagne flow'' scenario. The nitrogen content of these two HII regions is very low, definitely N/O<0.04 but possibly as low as N/O<0.01. Overall, the oxygen lines and dust continuum are weaker in star-forming objects in the SMC than in the LMC. We attribute this to the lower metallicity of the SMC compared to that of the LMC. Whilst the dust mass differs in proportion to metallicity, the oxygen mass differs less; both observations can be reconciled with higher densitie...

  16. A Spitzer Space Telescope far-infrared spectral atlas of compact sources in the Magellanic Clouds. I. The Large Magellanic Cloud

    CERN Document Server

    van Loon, Jacco Th; Gordon, Karl D; Meixner, Margaret; Shiao, Bernie; Boyer, Martha L; Kemper, F; Woods, Paul M; Tielens, A G G M; Marengo, Massimo; Indebetouw, Remy; Sloan, G C; Chen, C -H Rosie

    2009-01-01

    [abridged] We present 52-93 micron spectra obtained with Spitzer in the MIPS-SED mode, of a representative sample of luminous compact far-IR sources in the LMC. These include carbon stars, OH/IR AGB stars, post-AGB objects and PNe, RCrB-type star HV2671, OH/IR red supergiants WOHG064 and IRAS05280-6910, B[e] stars IRAS04530-6916, R66 and R126, Wolf-Rayet star Brey3a, Luminous Blue Variable R71, supernova remnant N49, a large number of young stellar objects, compact HII regions and molecular cores, and a background galaxy (z~0.175). We use the spectra to constrain the presence and temperature of cold dust and the excitation conditions and shocks within the neutral and ionized gas, in the circumstellar environments and interfaces with the surrounding ISM. Evolved stars, including LBV R71, lack cold dust except in some cases where we argue that this is swept-up ISM. This leads to an estimate of the duration of the prolific dust-producing phase ("superwind") of several thousand years for both RSGs and massive AGB...

  17. The Space Infrared Interferometric Telescope (SPIRIT): High-resolution imaging and spectroscopy in the far-infrared

    CERN Document Server

    Leisawitz, David; Barger, Amy; Benford, Dominic; Blain, Andrew; Boyle, Rob; Broderick, Richard; Budinoff, Jason; Carpenter, John; Caverly, Richard; Chen, Phil; Cooley, Steve; Cottingham, Christine; Crooke, Julie; DiPietro, Dave; DiPirro, Mike; Femiano, Michael; Ferrer, Art; Fischer, Jacqueline; Gardner, Jonathan P; Hallock, Lou; Harris, Kenny; Hartman, Kate; Harwit, Martin; Hillenbrand, Lynne; Hyde, Tupper; Jones, Drew; Kellogg, Jim; Kogut, Alan; Kuchner, Marc; Lawson, Bill; Lecha, Javier; Lecha, Maria; Mainzer, Amy; Mannion, Jim; Martino, Anthony; Mason, Paul; Mather, John; McDonald, Gibran; Mills, Rick; Mundy, Lee; Ollendorf, Stan; Pellicciotti, Joe; Quinn, Dave; Rhee, Kirk; Rinehart, Stephen; Sauerwine, Tim; Silverberg, Robert; Smith, Terry; Stacey, Gordon; Stahl, H Philip; Staguhn, Johannes; Tompkins, Steve; Tveekrem, June; Wall, Sheila; Wilson, Mark C

    2007-01-01

    We report results of a recently-completed pre-Formulation Phase study of SPIRIT, a candidate NASA Origins Probe mission. SPIRIT is a spatial and spectral interferometer with an operating wavelength range 25 - 400 microns. SPIRIT will provide sub-arcsecond resolution images and spectra with resolution R = 3000 in a 1 arcmin field of view to accomplish three primary scientific objectives: (1) Learn how planetary systems form from protostellar disks, and how they acquire their inhomogeneous composition; (2) characterize the family of extrasolar planetary systems by imaging the structure in debris disks to understand how and where planets of different types form; and (3) learn how high-redshift galaxies formed and merged to form the present-day population of galaxies. Observations with SPIRIT will be complementary to those of the James Webb Space Telescope and the ground-based Atacama Large Millimeter Array. All three observatories could be operational contemporaneously.

  18. BOHENDI@FELIX: Probing the Far-Infrared Fingerprint of Small Clusters in Helium Nanodroplets with a Free Electron Laser

    Science.gov (United States)

    Schwaab, Gerhard; Schwan, Raffael; Mani, Devendra; Dey, Arghya; Fischer, Theo; Kaufmann, Matin; Redlich, Britta; van der Meer, Lex; Havenith, Martina

    2016-06-01

    Recently, we have installed a helium nanodroplet machine [1,2] at the free electron beamline FELIX in Nijmegen. The current setup allows to study neutral molecules and molecular complexes in the full spectral range from 500--3000 cm-1. First proof of principle experiments using the strong absorber SF_6 were used to verify the overall alignment between helium nanodroplet beam and the FELIX radiation source. Applications so far included the study of small water clusters and the investigation of microsolvation of small solutes. These results will be presented and compared to recent theoretical predictions of the Bowman group.[3] [1] K. von Haeften et al., Phys. Rev. B. 73, 054502 (2006) [2] Choi et al., Int. Rev. Phys. Chem. 25, 15 (2006) [3] Samantha et al., Acc. Chem. Res. 47, 2700 (2014)

  19. An Atlas of Galaxy Spectral Energy Distributions from the Ultraviolet to the Mid-Infrared

    CERN Document Server

    Brown, Michael J I; Smith, J -D T; da Cunha, Elisabete; Jarrett, T H; Imanishi, Masatoshi; Armus, Lee; Brandl, Bernhard R; Peek, J E G

    2013-01-01

    We present an atlas of 129 spectral energy distributions for nearby galaxies, with wavelength coverage spanning from the UV to the mid-infrared. Our atlas spans a broad range of galaxy types, including ellipticals, spirals, merging galaxies, blue compact dwarfs and luminous infrared galaxies. We have combined ground-based optical drift-scan spectrophotometry with infrared spectroscopy from Spitzer and Akari, with gaps in spectral coverage being filled using MAGPHYS spectral energy distribution models. The spectroscopy and models were normalized, constrained and verified with matched-aperture photometry measured from Swift, GALEX, SDSS, 2MASS, Spitzer and WISE images. The availability of 26 photometric bands allowed us to identify and mitigate systematic errors present in the data. Comparison of our spectral energy distributions with other template libraries and the observed colors of galaxies indicates that we have smaller systematic errors than existing atlases, while spanning a broader range of galaxy types...

  20. Spectrally Enhanced Lighting Program Implementation for Energy Savings: Field Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, Kelly L.; Sullivan, Gregory P.; Armstrong, Peter R.; Richman, Eric E.; Matzke, Brett D.

    2006-08-22

    This report provides results from an evaluation PNNL conducted of a spectrally enhanced lighting demonstration project. PNNL performed field measurements and occupant surveys at three office buildings in California before and after lighting retrofits were made in August and December 2005. PNNL measured the following Overhead lighting electricity demand and consumption, Light levels in the workspace, Task lighting use, and Occupant ratings of satisfaction with the lighting. Existing lighting, which varied in each building, was replaced with lamps with correlated color temperature (CCT) of 5000 Kelvin, color rendering index (CRI) of 85, of varying wattages, and lower ballast factor electronic ballasts. The demonstrations were designed to decrease lighting power loads in the three buildings by 22-50 percent, depending on the existing installed lamps and ballasts. The project designers hypothesized that this reduction in electrical loads could be achieved by the change to higher CCT lamps without decreasing occupant satisfaction with the lighting.

  1. Results from a triple chord stellar occultation and far-infrared photometry of the trans-Neptunian object (229762) 2007 UK126

    Science.gov (United States)

    Schindler, K.; Wolf, J.; Bardecker, J.; Olsen, A.; Müller, T.; Kiss, C.; Ortiz, J. L.; Braga-Ribas, F.; Camargo, J. I. B.; Herald, D.; Krabbe, A.

    2017-03-01

    Context. A stellar occultation by a trans-Neptunian object (TNO) provides an opportunity to probe the size and shape of these distant solar system bodies. In the past seven years, several occultations by TNOs have been observed, but mostly from a single location. Only very few TNOs have been sampled simultaneously from multiple locations. Sufficient data that enable a robust estimation of shadow size through an ellipse fit could only be obtained for two objects. Aims: We present the first observation of an occultation by the TNO 2007 UK126 on 15 November 2014, measured by three observers, one nearly on and two almost symmetrical to the shadow's centerline. This is the first multi-chord dataset obtained for a so-called detached object, a TNO subgroup with perihelion distances so large that the giant planets have likely not perturbed their orbits. We also revisit Herschel/PACS far-infrared data, applying a new reduction method to improve the accuracy of the measured fluxes. Combining both datasets allows us to comprehensively characterize 2007 UK126. Methods: We use error-in-variable regression to solve the non-linear problem of propagating timing errors into uncertainties of the ellipse parameters. Based on the shadow's size and a previously reported rotation period, we expect a shape of a Maclaurin spheroid and derive a geometrically plausible size range. To refine our size estimate of 2007 UK126, we model its thermal emission using a thermophysical model code. We conduct a parametric study to predict far-infrared fluxes and compare them to the Herschel/PACS measurements. Results: The favorable geometry of our occultation chords, combined with minimal dead-time imaging, and precise GPS time measurements, allow for an accurate estimation of the shadow size (best-fitting ellipse with axes 645.80 ± 5.68 km × 597.81 ± 12.74 km) and the visual geometric albedo (pV = 15.0 ± 1.6%). By combining our analyses of the occultation and the far-infrared data, we can

  2. Energy Efficient LED Spectrally Matched Smart Lighting Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovative Imaging and Research has teamed with the University of Southern Mississippi to develop a novel energy efficient smart light system. Smart lighting adds an...

  3. Energy Efficient LED Spectrally Matched Smart Lighting Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovative Imaging and Research and the University of Houston Clear Lake have teamed to develop a widely extensible, affordable, energy efficient, smart lighting...

  4. Spectral shape variation of interstellar electrons at high energies

    Science.gov (United States)

    Tan, L. C.

    1985-01-01

    The high energy electron spectrum analysis has shown that the electron intensity inside the H2 cloud region, or in a spiral arm, should be much lower than that outside it and the observed electron energy spectrum should flatten again at about 1 TeV. In the framework of the leady box model the recently established rigidity dependence of the escape pathlength of cosmic rays would predict a high energy electron spectrum which is flatter than the observed one. This divergence is explained by assuming that the leaky box model can only apply to cosmic ray heavy nuclei, and light nuclei and electrons in cosmic rays may have different behaviors in the interstellar propagation. Therefore, the measured data on high energy electrons should be analyzed based on the proposed nonuniform galactic disk (NUGD) mode.

  5. Far-infrared line spectra of active galaxies from the Herschel/PACS Spectrometer: the complete database

    CERN Document Server

    Fernández-Ontiveros, J A; Pereira-Santaella, M; Malkan, M A; Andreani, P; Dasyra, K M

    2016-01-01

    We present a coherent database of spectroscopic observations of far-IR fine-structure lines from the Herschel/PACS archive for a sample of 170 local AGN, plus a comparison sample of 20 starburst galaxies and 43 dwarf galaxies. Published Spitzer/IRS and Herschel/SPIRE line fluxes are included to extend our database to the full 10-600 $\\mu m$ spectral range. The observations are compared to a set of CLOUDY photoionisation models to estimate the above physical quantities through different diagnostic diagrams. We confirm the presence of a stratification of gas density in the emission regions of the galaxies, which increases with the ionisation potential of the emission lines. The new [OIV]25.9$\\mu m$/[OIII]88$\\mu m$ vs [NeIII]15.6$\\mu m$/[NeII]12.8$\\mu m$ diagram is proposed as the best diagnostic to separate: $i)$ AGN activity from any kind of star formation; and $ii)$ low-metallicity dwarf galaxies from starburst galaxies. Current stellar atmosphere models fail to reproduce the observed [OIV]25.9$\\mu m$/[OIII]8...

  6. The Far-Infrared, UV and Molecular Gas Relation in Galaxies up to z=2.5

    CERN Document Server

    Nordon, R; Saintonge, A; Berta, S; Wuyts, S; Schreiber, N M Forster; Genzel, R; Magnelli, B; Poglitsch, A; Popesso, P; Rosario, D; Sturm, E; Tacconi, L J

    2012-01-01

    We use the infrared excess (IRX) FIR/UV luminosity ratio to study the relation between the effective UV attenuation (A_IRX) and the UV spectral slope (beta) in a sample of 450 19.3. Thus, we are able to study galaxies on and even below the main SFR-stellar mass relation (main sequence). We find that main sequence galaxies form a tight sequence in the IRX--beta plane, which has a flatter slope than commonly used relations. This slope favors a SMC-like UV extinction curve, though the interpretation is model dependent. The scatter in the IRX-beta plane, correlates with the position of the galaxies in the SFR-M plane. Using a smaller sample of galaxies with CO gas masses, we study the relation between the UV attenuation and the molecular gas content. We find a very tight relation between the scatter in the IRX-beta plane and the specific attenuation (S_A), a quantity that represents the attenuation contributed by the molecular gas mass per young star. S_A is sensitive to both the geometrical arrangement of stars ...

  7. Characterizing the Youngest Herschel-detected Protostars II. Molecular Outflows from the Millimeter and the Far-infrared

    CERN Document Server

    Tobin, John J; Manoj, P; Megeath, S Thomas; Karska, Agata; Nagy, Zsofia; Wyrowski, Friedrich; Fischer, William; Watson, Dan M; Stanke, Thomas

    2016-01-01

    We present CARMA CO (J=1-0) observations and Herschel PACS spectroscopy, characterizing the outflow properties toward extremely young and deeply embedded protostars in the Orion molecular clouds. The sample comprises a subset of the Orion protostars known as the PACS Bright Red Sources (PBRS) (Stutz et al. 2013). We observed 14 PBRS with CARMA and 8 of these 14 with Herschel, acquiring full spectral scans from 55 micron to 200 micron. Outflows are detected in CO (J=1-0) from 8 of 14 PBRS, with two additional tentative detections; outflows are also detected from the outbursting protostar HOPS 223 (V2775 Ori) and the Class I protostar HOPS 68. The outflows have a range of morphologies, some are spatially compact, i > 20 deg). This confirms the interpretation of the very red 24 micron to 70 micron colors of the PBRS as a signpost of high envelope densities, with only one (possibly two) cases of the red colors resulting from edge-on inclinations. We detect high-J (J_up > 13) CO lines and/or H_2O lines from 5 of ...

  8. Cardiac Function Evaluation Analyzing Spectral Components due to the Consumption of Energy Drinks

    Directory of Open Access Journals (Sweden)

    Md. Bashir Uddin

    2014-05-01

    Full Text Available The aim of this study is to investigate the effect of energy drinks consumption on cardiac function of human being by analyzing the spectral components of pulse and ECG of several healthy people. Using pulse transducer connected with MP36 (Biopac, USA data acquisition unit, pulse recordings were performed. With electrode lead set connected to the same MP36 data acquisition unit, ECG recordings were also performed. At before and after the consumption of energy drinks available in Bangladesh, pulse and ECG recordings as well as analysis were performed with Biopac software. After having energy drinks, the spectral components such as power of spectral density and amplitude of fast Fourier transform of pulse signal decreased about 47.5 and 37%, respectively. In case of ECG signal, the spectral components such as power of spectral density and amplitude of fast Fourier transform increased about 17 and 7.5% within a short interval about 0-20 min, then effective decrements about 10 and 18.5%, respectively started for long duration. Analyzing spectral parameters, the findings highlight the adverse impacts on cardiac function which may cause cardiac abnormality as well as severe cardiac disease due to the regular consumption of energy drinks.

  9. OH far-infrared emission from low- and intermediate-mass protostars surveyed with Herschel-PACS

    DEFF Research Database (Denmark)

    Wampfler, Susanne Franziska; Bruderer, S.; Karska, A.

    2013-01-01

    are sufficiently high. Using realistic source parameters and radiation fields, it is shown for the case of Ser SMM1 that radiative pumping plays an important role in transitions arising from upper level energies higher than 300 K. The compact emission in the low-mass sources and the required presence of a strong...

  10. Nearby supernova remnants and the cosmic-ray spectral hardening at high energies

    CERN Document Server

    Thoudam, Satyendra

    2011-01-01

    Recent measurements of cosmic-ray spectra of several individual nuclear species by the CREAM, TRACER, and ATIC experiments indicate a change in the spectral index of the power laws at TeV energies. Possible explanations among others include non linear diffusive shock acceleration of cosmic-rays, different cosmic-ray propagation properties at higher and lower energies in the Galaxy and the presence of nearby sources. In this paper, we show that if supernova remnants are the main sources of cosmic rays in our Galaxy, the effect of the nearby remnants can be responsible for the observed spectral changes. Using a rigidity dependent escape of cosmic-rays from the supernova remnants, we explain the apparent observed property that the hardening of the helium spectrum occurs at relatively lower energies as compared to the protons and also that the spectral hardening does not persist beyond $\\sim (20-30)$ TeV energies.

  11. Energy calibration of the pixels of spectral X-ray detectors.

    Science.gov (United States)

    Panta, Raj Kumar; Walsh, Michael F; Bell, Stephen T; Anderson, Nigel G; Butler, Anthony P; Butler, Philip H

    2015-03-01

    The energy information acquired using spectral X-ray detectors allows noninvasive identification and characterization of chemical components of a material. To achieve this, it is important that the energy response of the detector is calibrated. The established techniques for energy calibration are not practical for routine use in pre-clinical or clinical research environment. This is due to the requirements of using monochromatic radiation sources such as synchrotron, radio-isotopes, and prohibitively long time needed to set up the equipment and make measurements. To address these limitations, we have developed an automated technique for calibrating the energy response of the pixels in a spectral X-ray detector that runs with minimal user intervention. This technique uses the X-ray tube voltage (kVp) as a reference energy, which is stepped through an energy range of interest. This technique locates the energy threshold where a pixel transitions from not-counting (off) to counting (on). Similarly, we have developed a technique for calibrating the energy response of individual pixels using X-ray fluorescence generated by metallic targets directly irradiated with polychromatic X-rays, and additionally γ-rays from (241)Am. This technique was used to measure the energy response of individual pixels in CdTe-Medipix3RX by characterizing noise performance, threshold dispersion, gain variation and spectral resolution. The comparison of these two techniques shows the energy difference of 1 keV at 59.5 keV which is less than the spectral resolution of the detector (full-width at half-maximum of 8 keV at 59.5 keV). Both techniques can be used as quality control tools in a pre-clinical multi-energy CT scanner using spectral X-ray detectors.

  12. Energy Criterion for the Spectral Stability of Discrete Breathers

    Science.gov (United States)

    Kevrekidis, Panayotis G.; Cuevas-Maraver, Jesús; Pelinovsky, Dmitry E.

    2016-08-01

    Discrete breathers are ubiquitous structures in nonlinear anharmonic models ranging from the prototypical example of the Fermi-Pasta-Ulam model to Klein-Gordon nonlinear lattices, among many others. We propose a general criterion for the emergence of instabilities of discrete breathers analogous to the well-established Vakhitov-Kolokolov criterion for solitary waves. The criterion involves the change of monotonicity of the discrete breather's energy as a function of the breather frequency. Our analysis suggests and numerical results corroborate that breathers with increasing (decreasing) energy-frequency dependence are generically unstable in soft (hard) nonlinear potentials.

  13. MgF2 as a material exhibiting all-angle negative refraction and subwavelength imaging due to the phonon response in the far infrared

    Science.gov (United States)

    Macêdo, R.; Rodrigues da Silva, R.; Dumelow, T.; da Costa, J. A. P.

    2014-01-01

    We consider the possibility of using MgF2 crystals as a suitable material for achieving all-angle negative refraction at far infrared frequencies. This possibility is associated with the highly anisotropic nature of the phonon response, leading to dielectric tensor components of opposing signs. The results show that this phenomenon should occur at somewhat lower frequencies than that of quartz, which has previously been investigated experimentally, but with relatively high efficiency. We also simulate subwavelength imaging, through canalization, at 247 cm-1, corresponding to the frequency of a transverse optical phonon polarized perpendicular to the extraordinary axis. Our simulations show that the Fabry-Pérot condition (use of a slab of thickness equal to an integral number of half-wavelengths) is not necessarily helpful in achieving subwavelength resolution.

  14. Determination of the far infrared optical constants of η-doped bulk CdxHg1-xTe (CMT) by dispersive fourier transform spectroscopy

    Science.gov (United States)

    Shayesteh, S. Farjami; Dumelow, T.; Parker, T. J.; Benushis, T. I.; Ershov, S. N.; Vasilevskiy, M. I.

    1995-04-01

    Far infrared phase and amplitude reflectivity measurements have been made on two bulk CdxHg1-xTe mixed crystals with composition x=0.29 and x=0.22 by dispersive Fourier transform spectroscopy (DFTS). The results have been used to calculate the real and imaginary parts of the dielectric function (ɛ', ɛ″) from the Fresnel relations. A plasma contribution is observed in the spectra in addition to the phonon response. For both samples a broad but weak reflection band around 95 105 cm-1 is observed as well as the expected two-oscillator response from the HgTe-like and CdTe-like optical phonons. This feature is attributed to absorption due to phonon combination bands, but it is too broad to enable assignments to be made. There is no evidence of additional features in the CdTe region due to clustering.

  15. Investigation of terahertz waves propagating through far infrared/CO2 laser stealth-compatible coating based on one-dimensional photonic crystal

    Science.gov (United States)

    Wang, Qichao; Wang, Jiachun; Zhao, Dapeng; Zhang, Jikui; Li, Zhigang; Chen, Zongsheng; Zeng, Jie; Miao, Lei; Shi, Jiaming

    2016-11-01

    We propose a new method to disclose the camouflaged targets coated with far infrared/CO2 laser stealth-compatible coating by utilizing terahertz (THz) radar. A coating based on one-dimensional photonic crystal (1DPC) with a defect mode is specially designed and successfully prepared, which possesses a high reflectivity in 8-14 μm waveband and a low reflectivity at 10.6 μm, by alternating thin films of Ge, ZnSe and Si. The propagation characteristic of 0.3-2 THz wave at incident angle from 0° to 80° in such PC coating is investigated theoretically based on characteristic matrix method. The maximal transmittance is up to 92%, and the absorptivity keeps lower than 0.5% over the whole band. The results are verified by experiments, which demonstrate the feasibility of using THz radar to detect the targets covered with such stealth-compatible coatings.

  16. Optical performance of an ultra-sensitive horn-coupled transition-edge-sensor bolometer with hemispherical backshort in the far infrared

    CERN Document Server

    Audley, Michael D; Gao, Jian-Rong; Khosropanah, Pourya; Hijmering, Richard; Ridder, Marcel; Mauskopf, Philip D; Morozov, Dmitry; Trappe, Neil A; Doherty, Stephen

    2016-01-01

    The next generation of far infrared space observatories will require extremely sensitive detectors that can be realized only by combining extremely low intrinsic noise with high optical efficiency. We have measured the broad-band optical response of ultra-sensitive TES bolometers (NEP$\\approx2\\rm\\ aW/\\sqrt Hz$) in the 30--60-$\\mu\\rm m$ band where radiation is coupled to the detectors with a few-moded conical feedhorn and a hemispherical backshort. We show that these detectors have an optical efficiency of 60% (the ratio of the power detected by the TES bolometer to the total power propagating through the feedhorn). We find that the measured optical efficiency can be understood in terms of the modes propagating through the feedhorn with the aid of a spatial mode-filtering technique.

  17. Determination of the complex refractivity of Au, Cu and Al in terahertz and far-infrared regions from reflection spectra measurements

    Science.gov (United States)

    Mou, Yuan; Wu, Zhen-sen; Gao, Yan-qing; Yang, Zhi-qiang; Yang, Qiu-jie; Zhang, Geng

    2017-01-01

    A scheme to determine the complex refractivity of gold (Au), Copper (Cu) and Aluminum (Al) from measurements of ellipsometer and spectrometer are proposed in this paper. The reflection spectra of the metals from 4 THz to 40 THz are measured with spectrometer. The determined refractivity by Kramers-Kronig (KK) algorithm coincides with the measured results from ellipsometer in far infrared region. Drude model is invited to make the wing correction on the terahertz reflection spectra, which helps to eliminate the effects of the noises from spectrometer on KK algorithm. The calculated refractive indexes from measured spectra in terahertz region are in consistent with those from corrected reflection spectra. The advantage of the scheme is to obtain terahertz dispersion properties based on limited information in infrared region.

  18. Guided-wave approaches to spectrally selective energy absorption

    Science.gov (United States)

    Stegeman, G. I.; Burke, J. J.

    1987-01-01

    Results of experiments designed to demonstrate spectrally selective absorption in dielectric waveguides on semiconductor substrates are reported. These experiments were conducted with three waveguides formed by sputtering films of PSK2 glass onto silicon-oxide layers grown on silicon substrates. The three waveguide samples were studied at 633 and 532 nm. The samples differed only in the thickness of the silicon-oxide layer, specifically 256 nm, 506 nm, and 740 nm. Agreement between theoretical predictions and measurements of propagation constants (mode angles) of the six or seven modes supported by these samples was excellent. However, the loss measurements were inconclusive because of high scattering losses in the structures fabricated (in excess of 10 dB/cm). Theoretical calculations indicated that the power distribution among all the modes supported by these structures will reach its steady state value after a propagation length of only 1 mm. Accordingly, the measured loss rates were found to be almost independent of which mode was initially excited. The excellent agreement between theory and experiment leads to the conclusion that low loss waveguides confirm the predicted loss rates.

  19. Spectral Analysis of Biosignals to Evaluate Heart Activity due to the Consumption of Energy Drinks

    Directory of Open Access Journals (Sweden)

    Md. Bashir Uddin

    2016-08-01

    Full Text Available The heart activity is clearly evaluated in this study by analyzing spectral or frequency components of three Biosignals such as ECG, PPG and blood perfusion signal. This study is done with several healthy human subjects who are totally free from any type of cardiovascular diseases. ECG and PPG recordings were performed with electrode lead set and pulse transducer respectively connected to the same MP36 (Biopac, USA data acquisition unit. LDF measurements were performed with skin surface probe connected to LDF100C module on middle finger tip. This LDF module was connected to MP150 (Biopac, USA data acquisition unit. ECG, PPG and blood perfusion signal recordings were performed before and after having energy drinks available in Bangladesh. After consuming energy drinks, it is observed that the spectral or frequency components for ECG as well as PPG signal decreases with a significant rate from the instant of having ED. That is, the spectral parameters of heart activity decrease due to the consumption of energy drinks. The spectral analysis of LDF signal also results similar type of decrement in their spectral parameters for same type of energy drinks consumption. These results reflect adverse impacts of energy drinks consumption on heart activity.

  20. The Doppler Effect and Spectral Energy Distribution of Blazars

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The relativistic beaming model is adopted to discuss quantitatively the observational differences between radio-selected BL Lac objects (RBLs) and X-ray-selected BL Lac objects (XBLs), and between BL Lac objects and fiat spectrum radio quasars (FSRQs). The main results are the following: (1) In the Doppler cor-rected color-color (αin ro-αin ox -αox) diagram, XBLs and FSRQs occupy separated regions,while RBLs bridge the gap between them. These properties suggest that similar in- trinsic physical processes operate in all the objects under a range of intrinsic physical conditions. (2) Our results are consistent with the results of Sambruna, Maraschi and Urry (1996) from other methods. We show the αxox introduced by Sambruna to be a good index for describing the energy distribution because it represents the intrinsic energy distribution and includes the Doppler correction. (3) The Doppler effect of relativistic beaming is the main mechanism, and the physical differences (such as magnetic fields, electron energies) are also important complementary fac-tors for understanding the relation between XBLs and RBLs;