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Sample records for dark field far-infrared

  1. THE INFRARED ARRAY CAMERA DARK FIELD: FAR-INFRARED TO X-RAY DATA

    SciTech Connect

    Krick, J. E.; Surace, J. A.; Yan, L.; Lacy, M.; Thompson, D.; Ashby, M. L. N.; Hora, J.; Gorjian, V.; Frayer, D. T.; Egami, E.

    2009-11-01

    We present 20 band photometry from the far-IR to X-ray in the Spitzer Infrared Array Camera (IRAC) dark field. The bias for the near-IR camera on Spitzer is calibrated by observing a {approx}20' diameter 'dark' field near the north ecliptic pole roughly every two-to-three weeks throughout the mission duration of Spitzer. The field is unique for its extreme depth, low background, high quality imaging, time-series information, and accompanying photometry including data taken with Akari, Palomar, MMT, KPNO, Hubble, and Chandra. This serendipitous survey contains the deepest mid-IR data taken to date. This data set is well suited for studies of intermediate-redshift galaxy clusters, high-redshift galaxies, the first generation of stars, and the lowest mass brown dwarfs, among others. This paper provides a summary of the data characteristics and catalog generation from all bands collected to date as well as a discussion of photometric redshifts and initial and expected science results and goals. To illustrate the scientific potential of this unique data set, we also present here IRAC color-color diagrams.

  2. Near and far infrared observations of protostars and dark clouds

    NASA Astrophysics Data System (ADS)

    Suters, Mark Gerard

    1992-11-01

    Far infrared point source and extended emission data from the Infrared Astronomical Satellite (IRAS) survey are used to investigate the properties of star formation in the regions of high galactic latitude dark cloud complexes. The properties of individual sources are examined using near infrared spectroscopy and broad band spectral energy distributions. The IRAS signature of star formation is derived by comparing the far infrared colors of a sample of protostars with those of other common far infrared objects. The quality of the IRAS data is ignored for the purposes of this investigation. The criteria developed for identifying protostars from the IRAS Point Source Catalog discriminates against most non-protostellar objects, with the exception of galaxies and HII regions. Objects identified as protostellar according to other criteria are also likely to be identified by the criteria developed. Extended emission data in the far infrared is used to estimate the column density and temperature of several dark cloud complexes, and the optical extinction in the same regions is estimated with the Guide Star Catalog. Temperature and column density share an inverse relationship cloud cores are characterized by column densities above 1024 hydrogen atoms m-2 and temperatures around 20 K, while the inter cloud medium has column densities below 1023 atoms m-2 and temperatures above 50 K. The column density, as measured by IRAS, and the optical extinction appear to be related up to values of around 1025 atoms m-2 and 5 magnitudes respectively but the IRAS detectors appear insensitive to material at higher densities than these. Near infrared spectra of a variety of objects chosen for their youth, including IRAS sources which satisfy the protostar criteria, are investigated. These spectra are categorized into three distinct groups of increasing youth: (1) T Tauri-like spectra, with flat H and K band continua, lacking both Br-gamma emission and CO absorption; (2) FU Orilike spectra

  3. FAR-INFRARED EXTINCTION MAPPING OF INFRARED DARK CLOUDS

    SciTech Connect

    Lim, Wanggi; Tan, Jonathan C.

    2014-01-10

    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 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 ∼100 μm! Here we develop analysis methods of FIR images from Spitzer-MIPS and Herschel-PACS that allow quantitative measurements of cloud mass surface density, Σ. The method builds on that developed for MIR extinction mapping by Butler and Tan, in particular involving a search for independently saturated, i.e., very opaque, regions that allow measurement of the foreground intensity. We focus on three massive starless core/clumps in the Infrared Dark Cloud (IRDC) G028.37+00.07, deriving mass surface density maps from 3.5 to 70 μm. A by-product of this analysis is the measurement of the spectral energy distribution of the diffuse foreground emission. The lower opacity at 70 μm allows us to probe to higher Σ values, up to ∼1 g cm{sup –2} in the densest parts of the core/clumps. Comparison of the Σ maps at different wavelengths constrains the shape of the MIR-FIR dust opacity law in IRDCs. We find that it is most consistent with the thick ice mantle models of Ossenkopf and Henning. There is tentative evidence for grain ice mantle growth as one goes from lower to higher Σ regions.

  4. Far Infrared dropout galaxies in the Herschel GOODS fields

    NASA Astrophysics Data System (ADS)

    Cowie, Lennox

    The most massively star-forming galaxies in the universe are dust enshrouded and radiate primarily in the far-infrared. At high redshifts these galaxies cannot be easily found with ultraviolet or optical searches and constitute a missing portion of the universal star formation history determined with conventional techniques. Current studies suggest that these obscured galaxies contain a substantial fraction (about 20%) of the star formation out to a redshift of at least five. The goals of the present proposal are to refine these measurements, to search for yet higher redshift dusty galaxies, to study the morphologies and other properties of these galaxies, and to determine how the star formation rates in these galaxies correlate with the X-ray luminosities. The deepest Herschel imaging observations are of the two GOODS fields. Here we propose to extend the wavelength range of these observations to 850 micron, which is sensitive to very high redshifts (z out to about 8) where the rest-frame wavelength of the observations lies close to the peak in the thermal dust spectrum. We are making the 850 micron observations with the powerful SCUBA-2 camera on the JCMT telescope. Combined with the Spitzer and Herschel data, we will be able to measure the long wavelength spectral energy distributions of the SCUBA-2 detected galaxies and search for the highest redshift galaxies, which should be faint in the Spitzer and shorter wavelength Herschel data (mid and far-infrared dropout galaxies). We can obtain the morphologies from HST for those galaxies that are visible at optical or nearinfrared wavelengths, and we can measure the star formation rates for those that are detected with Chandra. Submillimeter detected luminous dusty galaxies have the highest star formation rates in the universe, and determining their properties and redshift distribution is key to understanding the formation of the most massive galaxies in the universe. The proposed work will add value to the Spitzer

  5. Far-infrared observations of young clusters embedded in the R Coronae Austrinae and RHO Ophiuchi dark clouds

    NASA Technical Reports Server (NTRS)

    Wilking, B. A.; Harvey, P. M.; Joy, M.; Hyland, A. R.; Jones, T. J.

    1985-01-01

    Multicolor far infrared maps in two nearby dark clouds, R Coronae Austrinae and rho Ophiuchi, were made in order to investigate the individual contribution of low mass stars to the energetics and dynamics of the surrounding gas and dust. Emission from cool dust associated with five low mass stars in Cr A and four in rho Oph was detected; their far infrared luminosities range from 2 far infrared luminosities L. up to 40 far infrared luminosities. When an estimate of the bolometric luminosity was possible, it was found that typically more than 50% of the star's energy was radiated longward of 20 micrometers. meaningful limits to the far infrared luminosities of an additional eleven association members in Cr A and two in rho Oph were also obtained. The dust optical depth surrounding the star R Cr A appears to be asymmetric and may control the dynamics of the surrounding molecular gas. The implications of the results for the cloud energetics and star formation efficiency in these two clouds are discussed.

  6. The Radio-Far Infrared Correlation in the NEP Deep Field

    NASA Astrophysics Data System (ADS)

    Barrufet, Laia; White, Glenn J.; Pearson, Chris; Serjeant, Stephen; Lim, Tanya; Matsuhara, Hideo; Oi, Nagisa; Karouzos, Marios; AKARI-NEP Team

    2017-03-01

    We report the results of a multi-wavelength study in the North Ecliptic Pole (NEP) deep field and examine the far infrared-radio correlation (FIRC) for high and low redshift objects. We have found a correlation between the GMRT data at 610 MHz and the Herschel data at 250 μm that has been used to define a spectral index. This spectral index shows no evolution against redshift. As a result of the study, we show a radio colour-infrared diagram that can be used as a redshift indicator.

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

    NASA Technical Reports Server (NTRS)

    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.

  8. Far-infrared observations of a star-forming region in the Corona Australis dark cloud

    NASA Technical Reports Server (NTRS)

    Cruz-Gonzalez, I.; Mcbreen, B.; Fazio, G. G.

    1984-01-01

    A high-resolution far-IR (40-250-micron) survey of a 0.9-sq-deg section of the core region of the Corona Australis dark cloud (containing very young stellar objects such as T Tauri stars, Herbig Ae and Be stars, Herbig-Haro objects, and compact H II regions) is presented. Two extended far-IR sources were found, one associated with the Herbig emission-line star R CrA and the other with the irregular emission-line variable star TY CrA. The two sources have substantially more far-IR radiation than could be expected from a blackbody extrapolation of their near-IR fluxes. The total luminosities of these sources are 145 and 58 solar luminosity, respectively, implying that the embedded objects are of intermediate or low mass. The infrared observations of the sources associated with R CrA and TY CrA are consistent with models of the evolution of protostellar envelopes of intermediate mass. However, the TY CrA source appears to have passed the evolutionary stage of expelling most of the hot dust near the central source, yielding an age of about 1 Myr.

  9. Far-infrared observations of a star-forming region in the Corona Australis dark cloud

    NASA Technical Reports Server (NTRS)

    Cruz-Gonzalez, I.; Mcbreen, B.; Fazio, G. G.

    1984-01-01

    A high-resolution far-IR (40-250-micron) survey of a 0.9-sq-deg section of the core region of the Corona Australis dark cloud (containing very young stellar objects such as T Tauri stars, Herbig Ae and Be stars, Herbig-Haro objects, and compact H II regions) is presented. Two extended far-IR sources were found, one associated with the Herbig emission-line star R CrA and the other with the irregular emission-line variable star TY CrA. The two sources have substantially more far-IR radiation than could be expected from a blackbody extrapolation of their near-IR fluxes. The total luminosities of these sources are 145 and 58 solar luminosity, respectively, implying that the embedded objects are of intermediate or low mass. The infrared observations of the sources associated with R CrA and TY CrA are consistent with models of the evolution of protostellar envelopes of intermediate mass. However, the TY CrA source appears to have passed the evolutionary stage of expelling most of the hot dust near the central source, yielding an age of about 1 Myr.

  10. Far infrared laser polarimetry and far forward scattering diagnostics for the C-2 field reversed configuration plasmas.

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. High sensitivity far infrared laser diagnostics for the C-2U advanced beam-driven field-reversed configuration plasmas

    SciTech Connect

    Deng, B. H. Beall, M.; Schroeder, J.; Settles, G.; Feng, P.; Kinley, J. S.; Gota, H.; Thompson, M. C.

    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.

  13. High sensitivity far infrared laser diagnostics for the C-2U advanced beam-driven field-reversed configuration plasmas.

    PubMed

    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 × 10(16) 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.

  14. On the internal field correction in far-infrared absorption of highly polar molecules in neat liquids and dilute solutions

    NASA Astrophysics Data System (ADS)

    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.

  15. Helmholtz resonator for electric field enhancement from visible to far-infrared

    NASA Astrophysics Data System (ADS)

    Chevalier, Paul; Bouchon, Patrick; Greffet, Jean-Jacques; Pelouard, Jean-Luc; Haidar, Riad; Pardo, Fabrice

    2015-01-01

    Here we present a 2D slit-box electromagnetic nanoantenna inspired by the acoustic Helmholtz resonator. It is able to concentrate the energy into tiny volumes, and a giant field intensity enhancement is observed throughout the slit. Noteworthily, we have shown that this field intensity enhancement can also be obtained in three dimensional structures that are polarization independent. In the Helmholtz nanoantenna, the field is enhanced in a hot volume and not a hot point, which is of great interest for applications requiring extreme light concentration, such as SEIRA, non-linear optics and biophotonics.

  16. Wide-field spatio-spectral interferometry for far-infrared space applications: A progress report

    NASA Astrophysics Data System (ADS)

    Leisawitz, David; Armstrong, J. T.; Bolcar, M. R.; Lyon, R.; Maher, S. F.; Memarsadeghi, N.; Rinehart, S.; Sinukoff, E.

    2014-01-01

    The NASA Astrophysics Roadmap Committee adopted the far-IR community’s vision and recommended far-IR interferometry as a needed capability in the 15 - 30 year time frame. The three major enabling technologies for such a mission are low-noise, high-speed detectors in small arrays; a demonstrated capability to cool optical system components to 4 K and focal planes to tens of mK with cryo-coolers; and the spatio-spectral interferometry (“double Fourier”) technique through which wide-field integral field spectroscopic data are derived from interferometric measurements. This paper reports on the current status of wide-field spatio-spectral interferometry and plans for maturation of the technique to space-flight readiness. Relatively simple spatial-spectral test patterns have been observed with the Wide-Field Imaging Interferometry Testbed at NASA’s Goddard Space Flight Center, and data cubes representing the observed scenes have been constructed based on the measured interferograms. A critical future milestone is the construction of an astronomically relevant, spatially and spectrally complex scene.

  17. Developing Wide-Field Spatio-Spectral Interferometry for Far-Infrared Space Applications

    NASA Technical Reports Server (NTRS)

    Leisawitz, David; Bolcar, Matthew R.; Lyon, Richard G.; Maher, Stephen F.; Memarsadeghi, Nargess; Rinehart, Stephen A.; Sinukoff, Evan J.

    2012-01-01

    Interferometry is an affordable way to bring the benefits of high resolution to space far-IR astrophysics. We summarize an ongoing effort to develop and learn the practical limitations of an interferometric technique that will enable the acquisition of high-resolution far-IR integral field spectroscopic data with a single instrument in a future space-based interferometer. This technique was central to the Space Infrared Interferometric Telescope (SPIRIT) and Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) space mission design concepts, and it will first be used on the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII). Our experimental approach combines data from a laboratory optical interferometer (the Wide-field Imaging Interferometry Testbed, WIIT), computational optical system modeling, and spatio-spectral synthesis algorithm development. We summarize recent experimental results and future plans.

  18. Far-infrared polarimetry/interferometry for poloidal magnetic field measurement on ZT-40M

    SciTech Connect

    Erickson, R.M.

    1986-06-01

    The measurement of internal magnetic field profiles may be a very important step in the understanding of magnetic confinement physics issues. The measurement of plasma-induced Faraday rotation is one of the more promising internal magnetic field diagnostics. This thesis describes the development of a heterodyne polarimeter/interferometer for internal poloidal magnetic field measurement on ZT-40M. Heterodyne techniques were employed because of the insensitivity to spurious signal amplitude changes that cause errors in other methods. Initial problems in polarimetric sensitivity were observed that were ultimately found to be related to discharge-induced motions of the constrained diagnostic access on ZT-40M. Grazing incidence motions of the constrained diagnostic access on ZT-40M. Grazing incidence reflections on metallic surfaces of the diagnostic ports caused polarization changes that affected the measurement accuracy. Installation of internally threaded sleeves to baffle the reflections eliminated the sensitivity problem, and allowed useful Faraday rotation measurements to be made. Simultaneous polarimetric and interferometric measurements have also been demonstrated. The ability to assemble a working heterodyne polarimeter/interferometer is no longer in question. The extension of the present system to multichord operation requires increased laser power and efficiency.

  19. A Spitzer Far-infrared Look at the NOAO-Deep Wide Field Survey

    NASA Astrophysics Data System (ADS)

    Le Floc'h, Emeric

    2006-12-01

    The NDFWS was imaged and spectroscopically followed-up in the midand far-IR (5-35mic, 70mic, 160mic) with the MIPS and IRS instruments on-board the Spitzer Space Telescope. I will discuss the main results that have been obtained so far from the combination of these observations with other wavelength data (X-ray, optical, radio) available across the field. This includes the IR characterization of the spectral energy distribution of IR/radio/Ly-alpha selected starburst galaxies and AGNs at high redshift, the study of AGN/starburst diagnostics based on mid-IR properties, the redshift distribution of mid-IR selected sources and the mid-IR luminosity function of quasars up to z 5. In particular, I will also emphasize the discovery of a population of 2

  20. Temperature and magnetic field tunability of composite metamaterials containing spherical semiconductor particles in far-infrared and terahertz regimes

    NASA Astrophysics Data System (ADS)

    Panahpour, Ali; Latifi, Hamid

    2010-12-01

    The effect of temperature and dc magnetic field variations on effective electromagnetic parameters of metamaterials (MTMs) containing spherical semiconductor particles is studied theoretically. The effect of temperature is taken into account through its influence on semiconductor carrier density and mobility. The effect of dc magnetic field is included using an extension of the Mie theory, describing the interaction of a plane wave with a gyrotropic sphere. The effective parameters such as relative permittivity and permeability are calculated by proper application of the Maxwell Garnett (MG) theory and its extensions to quasi-static condition and multi-phase structures. Based on these theories, the temperature and dc magnetic field tunability of three different MTM structures is investigated. First a single phase medium is considered which contains spherical semiconductor particles of one kind, randomly dispersed in a dielectric host. Then two multi-phase structures containing (a) two kinds of spherical semiconductor particles or (b) spherical particles with core-shell topology are investigated. The two multi-phase MTM structures can exhibit negative index of refraction in far-infrared spectral region. The measure of the temperature and dc magnetic field tunability of effective parameters such as relative permittivity and refractive index of the structures is evaluated and it is shown specifically that the real part of refractive index can be tuned to get negative, zero or positive values in far-IR or THz regimes, but the imaginary part of the index and the Figure of Merit (FOM) are also quite sensitive to the temperature and magnetic field variations. The tunable MTMs can find new applications in THz devices such as switches, tunable mirrors, isolators, converters, polarizers, filters and phase shifters.

  1. Looking at the bright side of the rho Ophiuchi dark cloud. Far infrared spectrophotometric observations of the rho Oph cloud with the ISO

    NASA Astrophysics Data System (ADS)

    Liseau, R.; White, G. J.; Larsson, B.; Sidher, S.; Olofsson, G.; Kaas, A.; Nordh, L.; Caux, E.; Lorenzetti, D.; Molinari, S.; Nisini, B.; Sibille, F.

    1999-04-01

    We present far infrared (45-195 mu m) spectrophotometric observations with the Iso-Lws of the active star forming rho Oph main cloud (L 1688). The [C ii] 158 mu m and [O i] 63 mu m lines were detected at each of the 33 positions observed, whereas the [O i] 145 mu m line was clearly seen toward twelve. The principal observational result is that the [C ii] 158 mu m line fluxes exhibit a clear correlation with projected distance from the dominant stellar source in the field (HD 147889). We interpret this in terms of Pdr-type emission from the surface layers of the rho Ophc. The observed [C ii] 158 mu m/[O i] 63 mu m flux ratios are larger than unity everywhere. A comparison of the [C ii] 158 mu m line emission and the Fir dust continuum fluxes yields estimates of the efficiency at which the gas in the cloud converts stellar to [C ii] 158 mu m photons (chi_ {_C II},>_{ ~ },0.5%). We first develop an empirical model, which provides us with a three dimensional view of the far and bright side of the dark rho Ophc, showing that the cloud surface towards the putative energy source is concave. This model also yields quantitative estimates of the incident flux of ultraviolet radiation (G_0 ~ , \\powten{1} - \\powten{2}) and of the degree of clumpiness/texture of the cloud surface (filling of the 80({') '} beam ~ ,0.2). Subsequently, we use theoretical models of Pdr s to derive the particle density, n(H), and the temperature structures, for T_gas and T_dust, in the surface layers of the rho Ophc. T_gas is relatively low, ~ ,60 K, but higher than T_dust ( ~ ,30 K), and densities are generally found within the interval (1-3) \\powten{4} cm(-3) . These Pdr models are moderately successful in explaining the Lws observations. They correctly predict the [O i] 63 mu m and [C ii] 158 mu m line intensities and the observed absence of any molecular line emission. The models do fail, however, to reproduce the observed small [O i] 63 mu m/[O i] 145 mu m ratios. We examine several possible

  2. Enhanced thermal radiation in terahertz and far-infrared regime by hot phonon excitation in a field effect transistor

    SciTech Connect

    Chung, Pei-Kang; Yen, Shun-Tung

    2014-11-14

    We demonstrate the hot phonon effect on thermal radiation in the terahertz and far-infrared regime. A pseudomorphic high electron mobility transistor is used for efficiently exciting hot phonons. Boosting the hot phonon population can enhance the efficiency of thermal radiation. The transistor can yield at least a radiation power of 13 μW and a power conversion efficiency higher than a resistor by more than 20%.

  3. NO EVIDENCE FOR EVOLUTION IN THE FAR-INFRARED-RADIO CORRELATION OUT TO z {approx} 2 IN THE EXTENDED CHANDRA DEEP FIELD SOUTH

    SciTech Connect

    Mao, Minnie Y.; Huynh, Minh T.; Helou, George; Norris, Ray P.; Dickinson, Mark; Frayer, Dave; Monkiewicz, Jacqueline A.

    2011-04-20

    We investigate the 70 {mu}m far-infrared-radio correlation (FRC) of star-forming galaxies in the Extended Chandra Deep Field South (ECDFS) out to z > 2. We use 70 {mu}m data from the Far-Infrared Deep Extragalactic Legacy Survey (FIDEL), which comprises the most sensitive ({approx}0.8 mJy rms) and extensive far-infrared deep field observations using MIPS on the Spitzer Space Telescope, and 1.4 GHz radio data ({approx}8 {mu}Jy beam{sup -1} rms) from the Very Large Array. In order to quantify the evolution of the FRC, we use both survival analysis and stacking techniques, which we find give similar results. We also calculate the FRC using total infrared luminosity and rest-frame radio luminosity, q{sub TIR}, and find that q{sub TIR} is constant (within 0.22) over the redshift range 0-2. We see no evidence for evolution in the FRC at 70 {mu}m, which is surprising given the many factors that are expected to change this ratio at high redshifts.

  4. Herschel's Far-Infrared View of Galaxy Formation and Evolution

    NASA Astrophysics Data System (ADS)

    Bock, James

    2014-01-01

    Herschel opened a new window on galaxy formation at far-infrared and sub-millimeter wavelengths, providing imaging in 6 spectral bands ranging from 70 - 500 um, diffraction-limited spatial resolution, and surveys ranging from deep well-studied fields to scanned maps covering large areas of sky. Herschel shows rapidly evolving far-infrared galaxy populations, with emission largely driven by dust-obscured star-formation. Herschel survey data mapped out the detailed evolution of the far-infrared luminosity function from our local universe to moderate redshifts. Combined with multi-wavelength surveys, we determined the role of far-infrared emission in diverse galaxy populations, including AGNs, as well as dust-obscured, Lyman-break, and radio galaxies. Herschel images provide a ready means to identify gravitationally lensed systems, expanding on the total number of known lenses, and providing spectacular high-redshift galaxies for detailed study. Observations of rich cluster fields produced new measurements on lensed galaxies, the extragalactic background, and the SZ effect. The analysis of Herschel images pioneered new statistical techniques to probe galaxies below the confusion limit, stacking on known populations to derive ensemble properties, and mapping large-scale structure through power spectral methods to explore the relationship between galaxy formation and the underlying distribution of dark matter. I will present recent results from Herschel extragalactic science observations, concentrating on the Herschel Multi-Tiered Extragalactic Survey (HerMES), with selected highlights from all surveys.

  5. The Far Infrared Earth

    NASA Technical Reports Server (NTRS)

    Harries, John; Carli, Bruno; Rizzi, Rolando; Serio, Carmine; Mlynczak, Martin G.; Palchetti, Luca; Maestri, T.; Brindley, H.; Masiello, Guido

    2007-01-01

    The paper presents a review of the far infrared (FIR) properties of the Earth's atmosphere, and the role of these properties in climate. These properties have been relatively poorly understood, and it is one of the purposes of this review to demonstrate that, in recent years, we have made great strides in improving this understanding. Seen from space, the Earth is a cool object, with an effective emitting temperature of about 255 K. This contrasts with a global mean surface temperature of 288 K, and is due primarily to strong absorption of outgoing longwave energy by water vapour, carbon dioxide and clouds (especially ice). A large fraction of this absorption occurs in the FIR, and so the Earth is effectively a FIR planet. The FIR is important in a number of key climate processes, for example the water vapour and cloud feedbacks (especially ice clouds). The FIR is also a spectral region which can be used to remotely sense and retrieve atmospheric composition in the presence of ice clouds. Recent developments in instrumentation have allowed progress in each of these areas, which are described, and proposals for a spaceborne FIR instrument are being formulated. It is timely to review the FIR properties of the clear and cloudy atmosphere, the role of FIR processes in climate, and its use in observing our planet from space.

  6. The physics of heterodyne detection in the far-infrared: Transition from electric-field to photon-absorption detection in a simple system

    NASA Technical Reports Server (NTRS)

    Teich, M. C.

    1980-01-01

    The history of heterodyne detection is reviewed from the radiowave to the optical regions of the electromagnetic spectrum with emphasion the submillimeter/far infrared. The transition from electric field to photon absorption detection in a simple system is investigated. The response of an isolated two level detector to a coherent source of incident radiation is calculated for both heterodyne and video detection. When the processes of photon absorption and photon emission cannot be distinguished, the relative detected power at double- and sum-frequencies is found to be multiplied by a coefficient, which is less than or equal to unity, and which depends on the incident photon energy and on the effective temperature of the system.

  7. Adiabatic Demagnetization Cooler For Far Infrared Detector

    NASA Astrophysics Data System (ADS)

    Sato, Akio; Yazawa, Takashi; Yamamoto, Junya

    1988-11-01

    An small adiabatic demagnetization cooler for an astronomical far infrared detector has been built. Single crystals of manganese ammonium sulphate and chromium potassium alum, were prepared as magnetic substances. The superconducting magnet was indirectly cooled and operated by small current up to 13.3 A, the maximum field being 3.5 T. As a preliminary step, adiabatic demagnetization to zero field was implemented. The lowest temperature obtained was 0.5 K, for 5.0 K initial temperature.

  8. Clustering Properties of Far-infrared Sources in the Herschel infrared GALactic Survey (Hi-Gal) Science Demonstration Phase Fields.

    NASA Astrophysics Data System (ADS)

    Billot, Nicolas; Schisano, E.; Molinari, S.; Pestalozzi, M.; Hi-GAL Team

    2011-01-01

    While the study of star forming activity usually relies on fitting spectral energy distributions to probe the physical properties of forming stars, we explore an alternative method to complement this multi-wavelength strategy: we use a Minimum Spanning Tree (MST) algorithm to characterize the spatial distribution of Galactic Far-IR sources and derive their clustering properties. We aim at revealing the spatial imprint of different types of star forming processes, e.g. isolated spontaneous fragmentation of dense molecular clouds, or events of triggered star formation around Hii regions, and evidence global properties of star formation in the Galaxy. We plan on exploiting the entire HiGAL survey of the inner Galactic plane (270 square degrees observed in 5 bands between 70 and 500 microns, P.I. Sergio Molinari) to gather significant statistics on the clustering properties of star forming regions, and to look for possible correlations with source properties such as mass, temperature or evolutionary stage. In this poster we present a pilot study of our project on two 2×2 square degrees fields centered at longitudes l=30 and 59 degrees obtained during the Science Demonstration Phase (SDP) of the Herschel mission.

  9. Alternating-Gradient Photodetector For Far Infrared

    NASA Technical Reports Server (NTRS)

    Overhauser, Albert W.; Maserjian, Joseph

    1989-01-01

    Proposed detector of photons of wavelengths in range of 30 to 200 micrometer made of alternating layers of lightly and heavily negatively doped germanium. Formed in sequence by conventional chemical-vapor deposition. Alternating-gradient structure enhances collection of photogenerated charge carriers while suppressing dark current, thus achieving high detectivity. Alternating layers of n+ and n- germanium provides high detectivity in far-infrared spectral region. Also possible to make similar structures with positive doping and with other semiconductors as silicon or gallium arsenide to obtain various spectral response.

  10. Dynamic quasi-energy-band modulation and exciton effects in biased superlattices driven by a two-color far-infrared field: Disappearance of dynamic localization

    NASA Astrophysics Data System (ADS)

    Yashima, Kenta; Hino, Ken-Ichi; Toshima, Nobuyuki

    2003-12-01

    A theoretical study of the optical and electronic properties of semiconductor superlattices in ac-dc fields, termed the dynamic Wannier-Stark ladder (DWSL), is done. The biased superlattices are driven by two far-infrared fields with different frequencies and relative phase of δ. Here, the frequency of the first laser is equal to the Bloch frequency ωB of the system under study, while that of the second laser is equal to 2ωB. Quasienergies of the DWSL are calculated based on the Floquet theorem, and the associated linear photoabsorption spectra are evaluated. For δ=0, a gourd-shaped quasi-energy structure characteristic of both dynamic localization (DL) and delocalization (DDL), similar to the usual DWSL driven by a single laser, appears. By changing the ratio of the two laser strengths, however, the width of the quasi-energy band and the locations of both DL and DDL vary noticeably. As for δ≠0, on the other hand, band collapse and the associated DL do not necessarily follow. In fact, DL vanishes and the quasi-energy degeneracy is lifted in a certain range of δ. Just DDL remains over the entire range of the laser strength, eventually resulting in a plateaulike band structure in the linear absorption spectra. The basic physics underlying this phenomenon, which can be readily interpreted in terms of a closed analytical expression, is that all quasi-energies for given crystal momenta are out of phase with each other as a function of laser strength without converging to a single point of energy. This is a feature of this DWSL which sharply distinguishes it from a conventional DWSL generated using a single laser to drive it. Furthermore, an exciton effect is incorporated with the above noninteracting problem, so that exciton dressed states are formed. It is found that this effect gives rise to more involved quasi-energy structures and a more pronounced release of the energy degeneracy of DL, leading again to the formation of a band structure in the absorption

  11. Far-infrared emission from dusty ellipticals

    NASA Technical Reports Server (NTRS)

    Walsh, Duncan; Knapp, Jill

    1990-01-01

    The incidence of dust lanes in elliptical galaxies has been estimated at approx. 40 percent by Sadler and Gerhard (1985), although the observed fraction is lower because of inclination effects. A similar percentage of ellipticals has been detected by the Infrared Astronomy Satellite (IRAS) at 100 microns (Knapp et al. 1989); these have far-infrared colors expected for emission from cool dust (S sub 60 micron/S sub 100 micron approx. 1/3). For the far-infrared detected galaxies, neither L sub 100 microns/L sub B nor L sub 60 microns/L sub 100 microns are very dependent on dust content, suggesting that the source of the infrared luminosity is the same in both cases; and hence that dust is responsible even when not detected optically. Despite this indication, L sub 100 microns does not prove to be a good indicator of the quantity of cool interstellar matter in elliptical galaxies, as measured by the mass of neutral hydrogen. There even exist several examples of ellipticals with dust, strong 100 micron flux density and sensitive limits on HI mass (Walsh et al. in preparation). Chief reasons for the lack of correlation include the existence of other important sources of far-IR power in ellipticals, such as nonthermal continuum emission extending from longer wavelengths in flat spectrum radio sources (Golombek, Miley and Neugebauer 1988); and the fact that far-infrared luminosity per unit dust mass is extremely sensitive to the temperature of the ambient radiation field, which is not accurately known. In addition to having their appearance distorted by dust, several ellipticals also show such features as shells, box-shaped isophotes or inner disks. These may be signatures of past mergers, which could also add to the ISM content of the system.

  12. Far Infrared Measurements of Cirrus

    NASA Technical Reports Server (NTRS)

    Nolt, I. G.; Vanek, M. D.; Tappan, N. D.; Minnis, P.; Alltop, J. L.; Ade, A. R.; Lee, C.; Hamilton, P. A.; Evans, K. F.; Evans, A. H.

    1999-01-01

    Improved techniques for remote sensing of cirrus are needed to obtain global data for assessing the effect of cirrus in climate change models. Model calculations show that the far infrared/sub-millimeter spectral region is well suited for retrieving cirrus Ice Water Path and particle size parameters. Especially useful cirrus information is obtained at frequencies below 60 cm-1 where single particle scattering dominates over thermal emission for ice particles larger than about 50 m. Earth radiance spectra have been obtained for a range of cloud conditions using an aircraft-based Fourier transform spectrometer. The Far InfraRed Sensor for Cirrus (FIRSC) is a Martin-Puplett interferometer which incorporates a polarizer for the beamsplitter and can be operated in either intensity or linear polarization measurement mode. Two detector channels span 10 to 140 cm-1 with a spectral resolution of 0.1 cm-1; achieving a Noise Equivalent Temperature of approximately 1K at 30 cm-1 in a 4 sec scan. Examples are shown of measured and modeled Earth radiance for a range of cloud conditions from 1998 and 1999 flights.

  13. The Far-infrared Earth

    NASA Astrophysics Data System (ADS)

    Harries, J.; Carli, B.; Rizzi, R.; Serio, C.; Mlynczak, M.; Palchetti, L.; Maestri, T.; Brindley, H.; Masiello, G.

    2008-12-01

    The paper presents a review of the far-infrared (FIR) properties of the Earth's atmosphere and their role in climate. These properties have been relatively poorly understood, and it is one of the purposes of this review to demonstrate that in recent years we have made great strides in improving this understanding. Seen from space, the Earth is a cool object, with an effective emitting temperature of about 255 K. This contrasts with a global mean surface temperature of ˜288 K and is due primarily to strong absorption of outgoing longwave energy by water vapor, carbon dioxide, and clouds (especially ice). A large fraction of this absorption occurs in the FIR, and so the Earth is effectively a FIR planet. The FIR is important in a number of key climate processes, for example, the water vapor and cloud feedbacks (especially ice clouds). The FIR is also a spectral region which can be used to remotely sense and retrieve atmospheric composition in the presence of ice clouds. Recent developments in instrumentation have allowed progress in each of these areas, which are described, and proposals for a spaceborne FIR instrument are being formulated. It is timely to review the FIR properties of the clear and cloudy atmosphere, the role of FIR processes in climate, and its use in observing our planet from space.

  14. Stark effect applicable to optically pumped far-infrared laser

    NASA Technical Reports Server (NTRS)

    Claspy, P. C.; Koo, K. P.

    1976-01-01

    Absorption measurements at CO2 laser frequencies were carried out as a function of Stark fields and CH3OH gas pressures to assess the effect of low electric field Stark tuning on methanol absorption at the P(12) 9.4 micron CO2 laser line, in a continuing search for coherent emitters at submillimeter wavelengths (far infrared). The line center absorption coefficient is found to increase five-fold with a 2.3 kV/cm Stark field at the 220 mtorr methanol pressure optimal for methanol far infrared lasing. The low electric field Stark tuning encourages efforts to enhance the pumping efficiency of a methanol far infrared laser at its normal optimum operating pressure, and suggests that significant Stark field induced frequency modulation of the far IR laser output is feasible.

  15. Grain Alignment and the Magnetic Field Geometry in the Filamentary Dark Cloud GF 9

    NASA Astrophysics Data System (ADS)

    Jones, Terry Jay

    2003-06-01

    We present measurements of the interstellar polarization at 1.65 μm of stars shining through the filamentary dark cloud GF 9. Unlike many dark clouds, the interstellar polarization through GF 9 increases significantly with increasing extinction through the cloud. We find the magnetic field geometry in GF 9-core is very smooth, in agreement with results from far-infrared polarimetry by Clemens, Kraemer, & Ciardi (published in 1999). Our much more limited results for GF 9-filament are consistent with a disordered field, also in agreement with the far-infrared polarimetry. Comparison of the near-infrared and far-infrared position angles suggests that there is a moderate rotation in the projected magnetic field direction from the exterior to the interior of GF 9-core.

  16. Tunable Far Infrared Studies in Support of Stratospheric Measurements

    NASA Technical Reports Server (NTRS)

    Chance Kelly; Park, K.; Nolt, I. G.; Evenson, K. M.

    1998-01-01

    The research performed during this reporting period has been a collaboration between institutions including the Smithsonian Astrophysical Observatory, the National Institute of Standards and Technology, the University of Oregon, and the NASA Langley Research Center. The program has included fully line-resolved measurements of submillimeter and far infrared spectroscopic line parameters (pressure broadening coefficients and their temperature dependences, and fine positions) for the analysis of field measurements of stratospheric constituents, far infrared database improvements, and studies for improved satellite measurements of the Earth's atmosphere. This research program is designed to enable the full utilization of spectra obtained in far infrared/submillimeter field measurements, such as FIRS-2, FILOS, IBEX, SLS, EosMLS, and proposed NASA and European Space Agency measurements of ClO and OH (e.g., PIRAMHYD) for the retrieval of accurate stratospheric altitude profiles of key trace gases involved in ozone layer photochemistry.

  17. Radio continuum, far infrared and star formation

    NASA Technical Reports Server (NTRS)

    Wielebinski, R.; Wunderlich, E.; Klein, U.; Hummel, E.

    1987-01-01

    A very tight correlation was found between the radio emission and the far infrared emission from galaxies. This has been found for various samples of galaxies and is explained in terms of recent star formation. The tight correlation would imply that the total radio emission is a good tracer of star formation. The correlation between the radio power at 5 GHz and the far infrared luminosity is shown. The galaxies are of various morphological types and were selected from the various IRAS circulars, hence the sample is an infrared selected sample. The far infrared luminosities were corrected for the dust temperature. This is significant because it decreases the dispersion in the correlation.

  18. Far infrared supplement: Catalog of infrared observations

    NASA Technical Reports Server (NTRS)

    Gezari, D. Y.; Schmitz, M.; Mead, J. M.

    1984-01-01

    The Far Infrared Supplement: catalog of infrared observations summarizes all infrared astronomical observations at far infrared wavelengths published in the scientific literature between 1965 and 1982. The Supplement list contains 25% of the observations in the full catalog of infrared observations (C10), and essentially eliminates most visible stars from the listings. The Supplement is more compact than the main Catalog (it does not contain the bibliography and position index of the C10), and is intended for easy reference during astronomical observations.

  19. Far-infrared cameras for automotive safety

    NASA Astrophysics Data System (ADS)

    Lonnoy, Jacques; Le Guilloux, Yann; Moreira, Raphael

    2005-02-01

    Far Infrared cameras used initially for the driving of military vehicles are slowly coming into the area of commercial (luxury) cars while providing with the FIR imagery a useful assistance for driving at night or in adverse conditions (fog, smoke, ...). However this imagery needs a minimum driver effort as the image understanding is not so natural as the visible or near IR one. A developing field of FIR cameras is ADAS (Advanced Driver Assistance Systems) where FIR processed imagery fused with other sensors data (radar, ...) is providing a driver warning when dangerous situations are occurring. The communication will concentrate on FIR processed imagery for object or obstacles detection on the road or near the road. FIR imagery highlighting hot spots is a powerful detection tool as it provides a good contrast on some of the most common elements of the road scenery (engines, wheels, gas exhaust pipes, pedestrians, 2 wheelers, animals,...). Moreover FIR algorithms are much more robust than visible ones as there is less variability in image contrast with time (day/night, shadows, ...). We based our detection algorithm on one side on the peculiar aspect of vehicles, pedestrians in FIR images and on the other side on the analysis of motion along time, that allows anticipation of future motion. We will show results obtained with FIR processed imagery within the PAROTO project, supported by the French Ministry of Research, that ended in spring 04.

  20. Far-infrared polarimetry diagnostic for measurement of internal magnetic field dynamics and fluctuations in the C-MOD Tokamak (invited)a)

    NASA Astrophysics Data System (ADS)

    Bergerson, W. F.; Xu, P.; Irby, J. H.; Brower, D. L.; Ding, W. X.; Marmar, E. S.

    2012-10-01

    A laser-based (2.55 THz) mulitchord polarimeter is now operational on Alcator C-Mod and is used to make measurements of the internal magnetic field structure as well as plasma fluctuations. The polarimeter is designed to measure the Faraday effect for high-field (up to 8.3 T) and high-density (up to 5 × 1020 m-3) ITER relevant plasma conditions. Initial 3 chord tests are consistent with magnetic equilibrium reconstructions and indicate no measurable contamination from the toroidal magnetic field due to the Cotton-Mouton effect or misalignment. Time response of <1 μs enables the measurement of fast equilibrium temporal dynamics as well as high-frequency fluctuations.

  1. Far-infrared polarimetry diagnostic for measurement of internal magnetic field dynamics and fluctuations in the C-MOD Tokamak (invited).

    PubMed

    Bergerson, W F; Xu, P; Irby, J H; Brower, D L; Ding, W X; Marmar, E S

    2012-10-01

    A laser-based (2.55 THz) mulitchord polarimeter is now operational on Alcator C-Mod and is used to make measurements of the internal magnetic field structure as well as plasma fluctuations. The polarimeter is designed to measure the Faraday effect for high-field (up to 8.3 T) and high-density (up to 5 × 10(20) m(-3)) ITER relevant plasma conditions. Initial 3 chord tests are consistent with magnetic equilibrium reconstructions and indicate no measurable contamination from the toroidal magnetic field due to the Cotton-Mouton effect or misalignment. Time response of <1 μs enables the measurement of fast equilibrium temporal dynamics as well as high-frequency fluctuations.

  2. Far-Infrared Photoconductivity of High Purity n-GaAs in a Magnetic Field Using Rapid-Scan Fourier Transform Spectroscopy.

    DTIC Science & Technology

    1982-12-01

    sources SSP Three letter computer command for control of the sample spacing TGS Pyroelectric detector TI Triangle apodization function TP Trapezoidal...of the authors use notation other than (n,l,m). The high field limit is y>>l and the low field limit is y<<l where y = hwC /2R * (31) • = cyclotron...130). When one is input, the beam goes to detector one (DI) which is a TGS room temperature detector. Code 2 will direct the beam to detector two

  3. Dark-field competition

    NASA Astrophysics Data System (ADS)

    Baumbach, Christoph; mcissbc

    2014-04-01

    In reply to the physicsworld.com news story “Dark field illuminates X-ray imaging” (25 February, http://ow.ly/ulJnl), which concerns new research by Robert Cernik and colleagues (Proc. R. Soc. A 10.1098/rspa.2013.0629).

  4. OPTICAL-FAINT, FAR-INFRARED-BRIGHT HERSCHEL SOURCES IN THE CANDELS FIELDS: ULTRA-LUMINOUS INFRARED GALAXIES AT z > 1 AND THE EFFECT OF SOURCE BLENDING

    SciTech Connect

    Yan, Haojing; Stefanon, Mauro; Ma, Zhiyuan; Willner, S. P.; Ashby, Matthew L. N.; Somerville, Rachel; Davé, Romeel; Pérez-González, Pablo G.; Cava, Antonio; Wiklind, Tommy; Kocevski, Dale; Rafelski, Marc; Kartaltepe, Jeyhan; Cooray, Asantha; Koekemoer, Anton M.; Grogin, Norman A.

    2014-07-01

    The Herschel very wide field surveys have charted hundreds of square degrees in multiple far-IR (FIR) bands. While the Sloan Digital Sky Survey (SDSS) is currently the best resource for optical counterpart identifications over such wide areas, it does not detect a large number of Herschel FIR sources and leaves their nature undetermined. As a test case, we studied seven ''SDSS-invisible'', very bright 250 μm sources (S {sub 250} > 55 mJy) in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey fields where we have a rich multi-wavelength data set. We took a new approach to decompose the FIR sources, using the near-IR or the optical images directly for position priors. This is an improvement over the previous decomposition efforts where the priors are from mid-IR data that still suffer from the problem of source blending. We found that in most cases the single Herschel sources are made of multiple components that are not necessarily at the same redshifts. Our decomposition succeeded in identifying and extracting their major contributors. We show that these are all ultra-luminous infrared galaxies at z ∼ 1-2 whose high L {sub IR} is mainly due to dust-obscured star formation. Most of them would not be selected as submillimeter galaxies. They all have complicated morphologies indicative of mergers or violent instability, and their stellar populations are heterogeneous in terms of stellar masses, ages, and formation histories. Their current ultra-luminous infrared galaxy phases are of various degrees of importance in their stellar mass assembly. Our practice provides a promising starting point for developing an automatic routine to reliably study bright Herschel sources.

  5. Far-infrared surveys of the sky.

    PubMed

    Hoffmann, W F; Woolf, N J; Frederick, C L; Low, F J

    1967-07-14

    A series of far-infrared surveys of the sky is searching for thermal radiation from interstellar grains and for other localized sources of far-infrared radiation. A balloon-borne germanium bolometer, cooled by liquid helium, is used in association with a telescope and spectral filters. During two initial flights the response to a black-body source was mainly between 300 and 360 microns. Approximately half the celestial sphere was surveyed, including most of the northern Milky Way. The angular resolution was 2 degrees. Moon was the only source of thermal radiation detected. The upper limit on the differential flux, relative to background, from other sources was 2 x 10(-23) watt per square centimeter per hertz, corresponding to an antenna temperature of 0.6 degrees K in the Rayleigh-Jeans approximation, or 10 degrees K for a black body.

  6. Optically Pumped Far Infrared Molecular Lasers.

    DTIC Science & Technology

    1980-04-01

    third and fifth order nonlinear processes can exceed first order laser processes. An experimental study of the generation of a 22.653 GHz signal (the...prime, practical sources. There are no counterparts in the far infrared of devices like IMPATTs, magnetrons, laser diodes, gyrotrons , etc. While in...1,000 GHz , the only proven, high spectral quality, modest technology, coherent source available to all researchers in the area, is the opti- cally

  7. The Berkeley tunable far infrared laser spectrometers

    NASA Technical Reports Server (NTRS)

    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.

  8. Far infrared all-sky survey

    NASA Technical Reports Server (NTRS)

    Richards, Paul L.

    1991-01-01

    An all-sky survey at submillimeter waves is examined. Far-infrared all-sky surveys were performed using high-thoroughput bolometric detectors from a one-meter balloon telescope. Based on the large-bodied experience obtained with the original all-sky survey telescope, a number of radically different approaches were implemented. Continued balloon measurements of the spectrum of the cosmic microwave background were performed.

  9. Far infrared study of polymorphism of trimethylchlorosilane

    NASA Astrophysics Data System (ADS)

    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.

  10. The composite nature of Dust-Obscured Galaxies (DOGs) at z ˜ 2-3 in the COSMOS field - I. A far-infrared view

    NASA Astrophysics Data System (ADS)

    Riguccini, L.; Le Floc'h, E.; Mullaney, J. R.; Menéndez-Delmestre, K.; Aussel, H.; Berta, S.; Calanog, J.; Capak, P.; Cooray, A.; Ilbert, O.; Kartaltepe, J.; Koekemoer, A.; Lutz, D.; Magnelli, B.; McCracken, H.; Oliver, S.; Roseboom, I.; Salvato, M.; Sanders, D.; Scoville, N.; Taniguchi, Y.; Treister, E.

    2015-09-01

    Dust-Obscured Galaxies (DOGs) are bright 24 μm-selected sources with extreme obscuration at optical wavelengths. They are typically characterized by a rising power-law continuum of hot dust (TD ˜ 200-1000 K) in the near-IR indicating that their mid-IR luminosity is dominated by an active galactic nucleus (AGN). DOGs with a fainter 24 μm flux display a stellar bump in the near-IR and their mid-IR luminosity appears to be mainly powered by dusty star formation. Alternatively, it may be that the mid-IR emission arising from AGN activity is dominant but the torus is sufficiently opaque to make the near-IR emission from the AGN negligible with respect to the emission from the host component. In an effort to characterize the astrophysical nature of the processes responsible for the IR emission in DOGs, this paper exploits Herschel data (PACS + SPIRE) on a sample of 95 DOGs within the COSMOS field. We derive a wealth of far-IR properties (e.g. total IR luminosities; mid-to-far-IR colours; dust temperatures and masses) based on spectral energy distribution fitting. Of particular interest are the 24 μm-bright DOGs (F24 μm > 1 mJy). They present bluer far-IR/mid-IR colours than the rest of the sample, unveiling the potential presence of an AGN. The AGN contribution to the total 8-1000 μm flux increases as a function of the rest-frame 8 μm-luminosity irrespective of the redshift. This confirms that faint DOGs (L8 μm < 1012 L⊙) are dominated by star formation while brighter DOGs show a larger contribution from an AGN.

  11. Corrugated quantum well infrared photodetectors for far infrared detection

    NASA Astrophysics Data System (ADS)

    Choi, Kwong-Kit; Jhabvala, Murzy D.; Forrai, David; Sun, Jason; Endres, Darrel

    2011-06-01

    We have extended our investigation of corrugated quantum well infrared photodetector focal plane arrays (FPAs) into the far infrared regime. Specifically, we are developing the detectors for the thermal infrared sensor (TIRS) used in the Landsat Data Continuity Mission. To maintain a low dark current, we adopted a low doping density of 0.6×1018 cm-3 and a bound-to-bound state detector. The internal absorption quantum efficiency (QE) is calculated to be 25.4%. With a pixel fill factor of 80% and a substrate transmission of 70.9%, the external QE is 14.4%. To yield the theoretical conversion efficiency (CE), the photoconductive gain was measured and is 0.25 at 5 V, from which CE is predicted to be 3.6%. This value is in agreement with the 3.5% from the FPA measurement. Meanwhile, the dark current is measured to be 2.1×10-6 A/cm2 at 43 K. For regular infrared imaging above 8 μm, the FPA will have an noise equivalent temperature difference (NETD) of 16 mK at 2 ms integration time in the presence of 260 read noise electrons. The highest operability of the tested FPAs is 99.967%. With the CE agreement, we project the FPA performance in the far infrared regime up to 30 μm cutoff.

  12. Far-infrared spectrophotometer for astronomical observations

    NASA Technical Reports Server (NTRS)

    Moseley, H.; Silverberg, R. F.

    1981-01-01

    A liquid-helium-cooled far infrared spectrophotometer was built and used to make low resolution observations of the continua of several kinds of astronomical objects using the Kuiper Airborne Observatory. This instrument fills a gap in both sensitivity to continuum sources and spectral resolution between the broadband photometers with lambda/Delta lambda approximately 1 and spectrometers with lambda/Delta lambda greater than 50. While designed primarily to study planetary nebulae, the instrument permits study of the shape of the continua of many weak sources which cannot easily be observed with high resolution systems.

  13. Properties of DNA in the Far Infrared.

    DTIC Science & Technology

    1987-10-12

    measurements currently in hand. References 1. "The Optical Properties of Li- and Na-DNA Films" T. Weidlich , S.M. Lindsay and A. Rupprecht, Biopolymers...26, 439-453 (1987). 2. "The Origin of the A to B Transition in DNA Fibers and Films" S.M. Lindsay, S.A. Lee, J.W. Powell, T. Weidlich , C. DeMarco...S.M. Lindsay, J.W. Powell, T. Weidlich , N.J. Tao, G.D. Lewen and A. Rupprecht, Biopolymers, in press (1987). 3. "Far Infrared Spectroscopy on

  14. Far-infrared spectra of acetanilide revisited

    NASA Astrophysics Data System (ADS)

    Spire, A.; Barthes, M.; Kellouai, H.; De Nunzio, G.

    2000-03-01

    A new investigation of the temperature dependence of the far-infrared spectra of acetanilide and some isotopomers is presented. Four absorption bands are considered at 31, 42, 64, and 80 cm-1, and no significant change of their integrated intensity is observed when reducing the temperature. The temperature induced frequency shift values and other properties of these bands are consistent with an assignment as anharmonic lattice phonons. These results rule out the assignment of the 64, 80, and 106 cm-1 bands as normal modes of the polaronic excitation, as previously suggested.

  15. Far-infrared spectroscopy of galaxies

    NASA Technical Reports Server (NTRS)

    Stacey, G. J.

    1989-01-01

    Far infrared (FIR) spectral line emission from galaxies is discussed with respect to past, present and near future observations. A review of the importance of the FIR lines as probes of the interstellar medium is presented. The various fine structure emission lines detected from the archetypal starburst galaxy M82, and the (C II) line radiation which is now observed toward a large variety of external galaxies are discussed. The improvements allowed by the advent of the Stratospheric Observatory For Infrared Astronomy (SOFIA), the Infrared Space Observatory (ISO) and the Space Infrared Telescope Facility (SIRTF) are underlined.

  16. Far infrared studies of solid cyclohexane

    NASA Astrophysics Data System (ADS)

    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.

  17. Generating Far-Infrared Radiation By Two-Wave Mixing

    NASA Technical Reports Server (NTRS)

    Borenstain, Shmuel

    1992-01-01

    Far-infrared radiation 1 to 6 GHz generated by two-wave mixing in asymmetrically grown GaAs/AlxGa1-xAs multiple-quantum-well devices. Two near-infrared semiconductor diode lasers phase-locked. Outputs amplified, then combined in semiconductor nonlinear multiple-quantum-well planar waveguide. Necessary to optimize design of device with respect to three factors: high degree of confinement of electromagnetic field in nonlinear medium to maximize power density, phase matching to extend length of zone of interaction between laser beams in non-linear medium, and nonlinear susceptibility. Devices used as tunable local oscillators in heterodyne-detection radiometers.

  18. Far-infrared spectrum of sodium hydride

    NASA Astrophysics Data System (ADS)

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

    1987-03-01

    Rotational spectra in the v = 0, 1, 2, and 3 levels of the ground ( 1Σ) state of sodium hydride have been observed using tunable far-infrared radiation generated from the difference frequency between two CO 2 lasers. The Dunham coefficients, which have been determined without the use of optical data or isotopic scaling relations, are Y01 = 146 999.138(38) MHz, Y02 = -10.29481(54) MHz, Y03 = 6.243(49) × 10 -4 MHz, Y11 = -4109.912(68) MHz, Y12 = 0.14695(68) MHz, Y21 = 33.341(34) MHz, Y22 = -2.69(20) × 10 -3 MHz, and Y31 = -1.0517(55) MHz. The constants are typically an order of magnitude more accurate than the best values previously available, and where comparison is possible, agreement is found to be excellent.

  19. Niobium microbolometers for far-infrared detection

    SciTech Connect

    MacDonald, M.E.; Grossman, E.N.

    1995-04-01

    Microbolometers have been fabricated using a thin niobium film as the detector element. These detectors operate at room temperature, are impedance matched to planar antennas, and are suitable for broadband use at far-infrared wavelengths. The authors have achieved responsivities of up to 21 V/W at a bias of 6.4 mA, and electrical noise equivalent powers (NEP) of as low as 1.1{times}10{sup {minus}10} W/{radical}{ovr Hz} at 1 kHz at a bias of 3.6 mA. At this bias, the detectors are 1/f-noise limited below 1 kHz and are Johnson noise limited above 10 kHz. The 1/f noise in nV/{radical}{ovr Hz} increases approximately linearly with bias. This level of 1/f noise is approximately a factor of 7 below the best reported for bismuth microbolometers.

  20. Far-Infrared Heterodyne Spectrometer for SOFIA

    NASA Technical Reports Server (NTRS)

    Betz, A. L.; Boreiko, R. T.

    1998-01-01

    This report summarizes work done under NASA Grant NAG2-1062 awarded to the University of Colorado. The project goal was to evaluate the scientific capabilities and technical requirements for a far-infrared heterodyne spectrometer suitable for the SOFIA Airborne Observatory, which is now being developed by NASA under contract to the Universities Space Research Association (USRA). The conclusions detailed below include our specific recommendations for astronomical observations, as well as our intended technical approach for reaching these scientific goals. These conclusions were presented to USRA in the form of a proposal to build this instrument. USRA subsequently awarded the University of Colorado a 3-year grant (USRA 8500-98-010) to develop the proposed Hot-Electron micro-Bolometer (HEB) mixer concept for high frequencies above 3 THz, as well as other semiconductor mixer technologies suitable for high sensitivity receivers in the 2-6 THz frequency band.

  1. Far-Infrared Heterodyne Spectrometer for Sofia

    NASA Technical Reports Server (NTRS)

    Betz, A. L.

    1998-01-01

    The project goal was to evaluate the scientific capabilities and technical requirements for a far-infrared heterodyne spectrometer suitable for the SOFIA Airborne Observatory, which is now being developed by NASA under contract to the Universities Space Research Association (USRA). The conclusions detailed below include our specific recommendations for astronomical observations, as well as our intended technical approach for reaching these scientific goals. These conclusions were presented to USRA in the form of a proposal to build this instrument. USRA subsequently awarded the University of Colorado a 3-year grant to develop the proposed Hot-Electron micro-Bolometer (HEB) mixer concept for high frequencies above 3 THz, as well as other semiconductor mixer technologies suitable for high sensitivity receivers in the 2-6 THz frequency band.

  2. Tunable Far Infrared Studies in Support of Stratospheric Measurements

    NASA Technical Reports Server (NTRS)

    Chance, Kelly V.; Park, K.; Nolt, I. G.; Evenson, K. M.

    2001-01-01

    This report summarizes research done under NASA Grant NAG5-4653. The research performed under this grant has been a collaboration between institutions including the Smithsonian Astrophysical Observatory, the National Institute of Standards and Technology, the University of Oregon, and the NASA Langley Research Center. The program has included fully line-resolved measurements of submillimeter and far infrared spectroscopic line parameters (pressure broadening coefficients and their temperature dependences, and line positions) for the analysis of field measurements of stratospheric constituents, far infrared database improvements, and studies for improved satellite measurements of the Earth's atmosphere. This research program is designed to enable the full utilization of spectra obtained in far infrared/submillimeter field measurements, such as FIRS-2, FILOS, IBEX, SLS, EosMLS, and proposed European Space Agency measurements of OH (e.g., PIRAMHYD and SFINX) for the retrieval of accurate stratospheric altitude profiles of key trace gases involved in ozone layer photochemistry. For the analysis of the spectra obtained in the stratosphere from far infrared measurements it is necessary to have accurate values of the molecular parameters (line positions, strengths, and pressure broadening coefficients) for the measured molecules and for possible interfering species. Knowledge of line positions is in increasingly good shape, with some notable exceptions. The increase in position information includes research that has been performed in the present program of research on HO2, H2O, H2O2, O3, HCl, HF, HBr, HI, CO, OH, and ClO. Examples where further line position studies are necessary include hot band and minor isotopomer lines of some of the major trace species (H2O, O3) and normal lines of some triatomic and larger molecules (NO2). Knowledge of strengths is in generally good shape, since most of the lines are from electric dipole transitions whose intensities are well

  3. Two instruments for far-infrared astrophysics

    SciTech Connect

    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.

  4. Far-infrared Intensity Measurements of Methanol

    NASA Astrophysics Data System (ADS)

    Brauer, Carolyn; Sung, K.; Pearson, J. C.; Brown, L. R.; Xu, L. H.

    2009-12-01

    Line intensities of methanol (CH3OH) are generally derived using the dipole moments determined from Stark effect measurements. However, the rotational intensities typically do not account for the torsional dependence of the dipole moment, and are thus incomplete. This effect may be significant in some transitions and can lead to confusion in interpreting observational data. Given the expectations associated with modern observation facilities such as Herschel, ALMA and SOFIA, and the ubiquity of methanol in interstellar gas, precise knowledge of the methanol spectrum is critical. Furthermore, methanol has been used as a calibration gas for the Herschel HIFI instrument and precision intensity data facilitates calibration of the relative sideband gain and local oscillator mixer standing wave patterns. Because the torsional dependence of the dipole moment cannot be accurately calculated, it must be extracted from line intensity measurements. In this work, an empirical database of methanol line intensities from 300 to 500 cm-1 has been compiled from far-infrared measurements recorded on the Bruker IFS 125 HR Fourier transform spectrometer located at the Jet Propulsion Laboratory. This room temperature spectrum was taken at resolutions between 0.0014 and 0.0050 cm-1 using a 20.26 cm glass cell with wedged high-density polyethylene windows, and detected with a He-cooled bolometer. The results from this study will support the analyses of astronomical observations taken from orbit by the Herschel HIFI instrument.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Far infrared supplement: Catalog of infrared observations, second edition

    NASA Technical Reports Server (NTRS)

    Gezari, Daniel Y.; Schmitz, Marion; Mead, Jaylee M.

    1988-01-01

    The Far Infrared Supplement: Catalog of Infrared Observations summarizes all infrared astronomical observations at far infrared wavelengths (5 to 1000 microns) published in the scientific literature from 1965 through 1986. The Supplement list contain 25 percent of the observations in the full Catalog of Infrared Observations (CIO), and essentially eliminates most visible stars from the listings. The Supplement is thus more compact than the main catalog, and is intended for easy reference during astronomical observations. The Far Infrared Supplement (2nd Edition) includes the Index of Infrared Source Positions and the Bibliography of Infrared Astronomy for the subset of far infrared observations listed.

  7. Wave Propagation Through The Far Infrared Beamline At The CLS

    SciTech Connect

    Reininger, R.; May, T.

    2004-05-12

    One of the beamlines to become operational in the first phase at the Canadian Light Source will be dedicated to high resolution spectroscopy in the far infrared (FIR). The beamline includes three ellipsoidal mirrors and several plane mirrors that transport the beam from the bending magnet source to the FIR spectrometer. The F-number of the spectrometer is matched by the beamline optics, which relay the light via intermediate foci rather than by collimation used in mid infrared beamlines. The beamline has been designed using regular ray tracing and by propagating the electric fields generated at the magnet through the beamline optics. The fields were calculated using SRW and the propagations were performed with SRW, which assumes ideal lenses, and with a wave propagating program using the real optical surfaces. The simulations, based on wave propagation, show the significant diffraction effects at both the foci and optical surfaces due to the small electron beam, beamline aperture, and mirrors sizes.

  8. Development of far infrared detection techniques

    NASA Astrophysics Data System (ADS)

    Rieke, George

    1993-06-01

    This grant supports the development of a variety of advanced far infrared detection techniques that will be used in future NASA missions such as the Space Infrared Telescope Facility (SIRTF). These studies span the wavelength region of 30-200 microns and include development of focal planes and electronics that would utilize them. Efforts reported here represent collaborations among the University of Arizona's Steward Observatory; Lawrence Berkeley Laboratories (LBL); and the University of California at Berkeley. The overall goal of this program is to demonstrate extremely high performance detectors for low background applications between 30-200 microns. For the 40-120 micron region, the program is developing a 32x32 filled detector array. Previous work has demonstrated the required performance with a Z-Plane array architecture; we are now upgrading construction facilities and techniques to increase yields and reliability. We have completed the initial tradeoff analysis for the interconnects between the detectors and and readouts. We found satisfactory performance for both Flex-Cable and Tape Automated Bonding (TAB) devices, but analysis showed that an all-sapphire device would not meet our requirements. In addition, the effort continued to develop readouts that can operate close to the detector element temperature; success would substantially improve the manufacturability of the arrays. For the 100-200 micron range, previous work has demonstrated good performance with individual detector elements of stressed Ge:Ga; current efforts are to increase the quantum efficiency of these devices. Work continues to discover how to construct an alternate type of long wave detector, Ge:B Blocked Impurity Band devices. Following descoping of SIRTF, we are closing out the bolometer and refrigerator development. We documented the optical designs and approaches developed previously to meet the specific requirements of these detector types in terms of modulation of the signals for

  9. Development of far infrared detection techniques

    NASA Technical Reports Server (NTRS)

    Rieke, George

    1993-01-01

    This grant supports the development of a variety of advanced far infrared detection techniques that will be used in future NASA missions such as the Space Infrared Telescope Facility (SIRTF). These studies span the wavelength region of 30-200 microns and include development of focal planes and electronics that would utilize them. Efforts reported here represent collaborations among the University of Arizona's Steward Observatory; Lawrence Berkeley Laboratories (LBL); and the University of California at Berkeley. The overall goal of this program is to demonstrate extremely high performance detectors for low background applications between 30-200 microns. For the 40-120 micron region, the program is developing a 32x32 filled detector array. Previous work has demonstrated the required performance with a Z-Plane array architecture; we are now upgrading construction facilities and techniques to increase yields and reliability. We have completed the initial tradeoff analysis for the interconnects between the detectors and and readouts. We found satisfactory performance for both Flex-Cable and Tape Automated Bonding (TAB) devices, but analysis showed that an all-sapphire device would not meet our requirements. In addition, the effort continued to develop readouts that can operate close to the detector element temperature; success would substantially improve the manufacturability of the arrays. For the 100-200 micron range, previous work has demonstrated good performance with individual detector elements of stressed Ge:Ga; current efforts are to increase the quantum efficiency of these devices. Work continues to discover how to construct an alternate type of long wave detector, Ge:B Blocked Impurity Band devices. Following descoping of SIRTF, we are closing out the bolometer and refrigerator development. We documented the optical designs and approaches developed previously to meet the specific requirements of these detector types in terms of modulation of the signals for

  10. Sky input horn for a far-infrared interferometer

    NASA Technical Reports Server (NTRS)

    Miller, M. S.; Eichhorn, W. L.; Mather, J. C.

    1982-01-01

    A unique design has been developed whereby a compound parabolic concentrator (CPC) and a compound elliptical concentrator (CEC) are joined at their throats. The CPC serves as the field-defining optics, in that it accepts up to a certain maximum acceptance angle and then concentrates this accepted energy at its throat. Energy incident from angles greater than the acceptance angle is rejected. The CEC takes the energy concentrated at the CPC throat and then redirects this energy into a finite-sized pupil a given distance away. The considered design will be used as the sky input horn for a cryogenic far-infrared polarizing interferometer to be flown on NASA's Cosmic Background Explorer satellite. The interferometer will operate at 2 K and measure the 3-K cosmic background radiation of the universe in the 100-micrometer-1-cm spectral range.

  11. Far-infrared mapping of dusty elliptical galaxies

    NASA Technical Reports Server (NTRS)

    Lees, Joanna F.; Harper, D. A.; Rupen, Michael P.; Knapp, G. R.

    1994-01-01

    Preliminary results from a program to map the thermal far-infrared emission from cool dust in elliptical galaxies using the Yerkes 60-Channel Camera on the Kuiper Airborne Observatory (KAO) are presented. The 160 micron emission from the elliptical NGC 6542 is apparently extended over the optical galaxy whereas the 100 micron emission is unresolved. This implies a dust temperature gradient consistent with that expected for dust with Galactic properties exposed to the general interstellar radiation field of the elliptical galaxy. Observations of the elliptical NGC 5666 and the NGC 7463/4/5 compact group (consisting of the elliptical NGC 7464, the S0 NGC 7465, and the spiral NGC 7463) are also discussed.

  12. Manifestation of the Hofstadter butterfly in far-infrared absorption

    SciTech Connect

    Gudmundsson, V.; Gerhardts, R.R.

    1996-08-01

    The far-infrared absorption of a two-dimensional electron gas with a square-lattice modulation in a perpendicular constant magnetic field is calculated self-consistently within the Hartree approximation. For strong modulation and short period we obtain intrasubband and intersubband magnetoplasmon modes reflecting the subbands of the Hofstadter butterfly in two or more Landau bands. The character of the absorption and the correlation of the peaks to the number of flux quanta through each unit cell of the periodic potential depends strongly on the location of the chemical potential with respect to the subbands, or equivalently, on the density of electrons in the system. {copyright} {ital 1996 The American Physical Society.}

  13. THE SPITZER ARCHIVAL FAR-INFRARED EXTRAGALACTIC SURVEY

    SciTech Connect

    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.; Edwards, L.; Frayer, D.; Huynh, M.; Lacy, M.; Murphy, E.; Scarlata, C.; Shenoy, S.

    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.

  14. Field Flows of Dark Energy

    SciTech Connect

    Cahn, Robert N.; de Putter, Roland; Linder, Eric V.

    2008-07-08

    Scalar field dark energy evolving from a long radiation- or matter-dominated epoch has characteristic dynamics. While slow-roll approximations are invalid, a well defined field expansion captures the key aspects of the dark energy evolution during much of the matter-dominated epoch. Since this behavior is determined, it is not faithfully represented if priors for dynamical quantities are chosen at random. We demonstrate these features for both thawing and freezing fields, and for some modified gravity models, and unify several special cases in the literature.

  15. Annular-slot arrays as far-infrared bandpass filters.

    PubMed

    Krug, P A; Dawes, D H; McPhedran, R C; Wright, W; Macfarlane, J C; Whitbourn, L B

    1989-09-01

    Arrays of both annular and square annular slots in a conducting sheet on a dielectric substrate have been fabricated photolithographically. The structures are shown to behave as bandpass filters in the far infrared, with a resonant wavelength slightly larger than the average circumference or perimeter of the slot. The measured far-infrared transmittance of the annular array is approximately 76% of that predicted by theory, while its resonant frequency agrees with theory to within 5%.

  16. Statistical properties of dust far-infrared emission

    NASA Astrophysics Data System (ADS)

    Miville-Deschênes, M.-A.; Lagache, G.; Boulanger, F.; Puget, J.-L.

    2007-07-01

    Context: Far-infrared dust emission has a self-similar structure which reveals the complex dynamical processes that shape the interstellar medium. The description of the statistical properties of this emission gives important constraints on the physics of the interstellar medium but it is also a useful way to estimate the contamination of diffuse interstellar emission in the cases where it is considered a nuisance. Aims: The main goals of this analysis of the power spectrum and non-Gaussian properties of far-infrared dust emission are 1) to estimate the power spectrum of interstellar matter density in three dimensions; 2) to review and extend previous estimates of the cirrus noise due to dust emission; and 3) to produce simulated dust emission maps that reproduce the observed statistical properties. Methods: To estimate the statistical properties of dust emission we analyzed the power spectrum and wavelet decomposition of 100 μm IRIS data (an improved version of the IRAS data) over 55% of the sky. The simulation of realistic infrared emission maps is based on modified Gaussian random fields. Results: The main results are the following. 1) The cirrus noise level as a function of brightness has been previously overestimated. It is found to be proportional to < I> instead of < I>1.5, where < I> is the local average brightness at 100 μm. This scaling is in accordance with the fact that the brightness fluctuation level observed at a given angular scale on the sky is the sum of fluctuations of increasing amplitude with distance on the line of sight. 2) The spectral index of dust emission at scales between 5 arcmin and 12.5° is <γ>=-2.9 on average but shows significant variations over the sky. Bright regions have systematically steeper power spectra than diffuse regions. 3) The skewness and kurtosis of brightness fluctuations are high, indicative of strong non-Gaussianity. Unlike the standard deviation of the fluctuations, the skewness and kurtosis do not depend

  17. Polarization of far-infrared radiation from molecular clouds

    NASA Technical Reports Server (NTRS)

    Novak, G.; Gonatas, D. P.; Hildebrand, R. H.; Platt, S. R.; Dragovan, M.

    1989-01-01

    The paper reports measurements of the polarization of far-infrared emission from dust in nine molecular clouds. Detections were obtained in Mon R2, in the Kleinmann-Low (KL) nebula in Orion, and in Sgr A. Upper limits were set for six other clouds. A comparison of the 100 micron polarization of KL with that previously measured at 270 microns provides new evidence that the polarization is due to emission from magnetically aligned dust grains. Comparing the results for Orion with measurements at optical wavelengths, it is inferred that the magnetic field direction in the outer parts of the Orion cloud is the same as that in the dense core. This direction is nearly perpendicular to the ridge of molecular emission and is parallel to both the molecular outflow in KL and the axis of rotation of the cloud core. In Mon R2, the field direction which the measurements imply does not agree withthat derived from 0.9-2.2 micron polarimetry. The discrepancy is attributed to scattering in the near-infrared. In Orion and Sgr A, where comparisons are possible, the measurements are in good agreement with 10 micron polarization measurements.

  18. Biological activities caused by far-infrared radiation

    NASA Astrophysics Data System (ADS)

    Inoué, Shojiro; Kabaya, Morihiro

    1989-09-01

    Contrary to previous presumption, accumulated evidence indicates that far-infrared rays are biologically active. A small ceramic disk that emist far-infrared rays (4 16 μm) has commonly been applied to a local spot or a whole part of the body for exposure. Pioneering attempts to experimentally analyze an effect of acute and chronic radiation of far-infrared rays on living organisms have detected a growth-promoting effect in growing rats, a sleep-modulatory effect in freely behaving rats and an insomiac patient, and a blood circulation-enhancing effect in human skin. Question-paires to 542 users of far-infrared radiator disks embedded in bedelothes revealed that the majority of the users subjectively evaluated an improvement of their health. These effects on living organisms appear to be non-specifically triggered by an exposure to far-infrared rays, which eventually induce an increase in temperature of the body tissues or, more basically, an elevated motility of body fluids due to decrease in size of water clusters.

  19. FIS -- Far-Infrared Surveyor onboard the ASTRO-F

    NASA Astrophysics Data System (ADS)

    Kawada, M.

    2000-12-01

    The Far-Infrared Surveyor (FIS) is one of the two focal plane instruments of ASTRO-F which is a Japanese infrared astronomical satellite planned to launch in early 2004. The FIS is designed primarily to perform an all-sky survey in 4 photometric bands at wavelength of 50 - 200 micron. The sensitivity of the FIS is several ten times higher than IRAS (Infrared Astronomical Satellite) because of the improvement on the detector performance based on the recent device technology. The FIS is expected to provide a new generation all-sky catalog of infrared sources, which could become a standard database in many fields of astrophysics. The FIS also has spectroscopic capability which is realized by a Fourier transform spectrometer. The spectrometer covers 50 - 200 cm-1 in wavenumber with 0.2 cm-1 spectral resolution. The spectrometer is quite a powerful tool to reveal the physical properties of the objects such as new objects detected by the all-sky survey or known interesting sources.

  20. Far infrared emission and portable testing device of fine powders.

    PubMed

    Liang, Jinsheng; Meng, Junping; Ding, Yan; Wang, Peipeng; Gan, Kun

    2011-11-01

    In order for industrial and mining enterprises to fast detect the quality of fine mineral powders with far infrared emission, a simple testing model was set up according to the relationship between the emission intensity of powders and their surface temperature. The corresponding testing device was designed and assembled into three parts containing Constant Temperature Heating Part, Temperature Measuring Part and Sample Loading Part. By using the tourmaline mineral powders with far infrared emission as the research object and combining Fourier transform infrared spectroscopy, the calibration for the testing device was carried out. The results showed that the far infrared emission intensity of the tourmaline powders with different mining area and particle size could be judged. The testing results exhibited correct values when compared with those from FTIR measurements.

  1. High pressure far infrared spectroscopy of ionic solids

    NASA Technical Reports Server (NTRS)

    Lowndes, R. P.

    1974-01-01

    A high-pressure far-infrared cell operating at up to truly hydrostatic pressures of 8 kbar is described and used to determine the anharmonic self-energies associated with the transverse optic modes of ionic solids in which q approximately equals zero. The cell allows far-infrared studies in the spectral range below 120 reciprocal cm. The transverse optic modes were investigated to determine their mode Gruneisen constants and the pressure dependence of their inverse lifetimes in RbI, CsI, and TlCl.

  2. New Concepts for Far-Infrared and Submillimeter Space Astronomy

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J. (Editor); Leisawitz, David T. (Editor)

    2004-01-01

    The Second Workshop on New Concepts for Far-Infrared and Submillimeter Space Astronomy aimed to highlight the groundbreaking opportunities available for astronomical investigations in the far-infrared to submillimeter using advanced, space-based telescopes. Held at the University of Maryland on March 7-8, 2002, the Workshop was attended by 130 participants from 50 institutions, and represented scientists and engineers from many countries and with a wide variety of experience. The technical content featured 17 invited talks and 44 contributed posters, complemented by two sixperson panels to address questions of astronomy and technology.

  3. Unidirectionality of an optically pumped far infrared ring laser

    NASA Astrophysics Data System (ADS)

    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.

  4. Synchrotron-based far-infrared spectroscopy of nickel tungstate

    NASA Astrophysics Data System (ADS)

    Kalinko, A.; Kuzmin, A.; Roy, P.; Evarestov, R. A.

    2016-07-01

    Monoclinic antiferromagnetic NiWO4 was studied by far-infrared (30-600 cm-1) absorption spectroscopy in the temperature range of 5-300 K using the synchrotron radiation from SOLEIL source. Two isomorphous CoWO4 and ZnWO4 tungstates were investigated for comparison. The phonon contributions in the far-infrared range of tungstates were interpreted using the first-principles spin-polarized linear combination of atomic orbital calculations. No contributions from magnetic excitations were found in NiWO4 and CoWO4 below their Neel temperatures down to 5 K.

  5. Far-infrared spectroscopy of normal galaxies with LWS

    NASA Astrophysics Data System (ADS)

    Malhotra, S.; Helou, G.; Hollenbach, D.; Kaufman, M. J.; Lord, S. D.; Brauher, J. R.; Dale, D.; Lu, N. Y.; Beichman, C. A.; Dinerstein, H.; Hunter, D. A.; Lo, K. Y.; Rubin, R. H.; Silbermann, N.; Stacey, G. J.; Thronson, H. A.; Werner, M. W.

    1999-03-01

    The deficiency of [CII] (158 μ m) line emission in many normal and ultraluminous galaxies is one of the major surprises from ISO-LWS observations. We show that this is not an isolated phenomenon: there is a smooth decline in L[CII]/LFIR ratio with increasing dust temperature(as indicated by far-infrared colors Fν(60 μ m)/Fν(100 μ m), i.e. F60/F100) and star-formation activity (indicated by LFIR/LB), independent of their luminosity or morphology. In a sample of 60 normal galaxies, these trends span a factor of 100. Of the numerous explanations proposed for the L[CII]/LFIR variation the leading ones are (a) optical depth and extinction, (b) softer radiation field from old stellar populations (c) inefficient photoelectric heating by charged grains when the UV radiation density per gas atom (G0/n) is high. We can rule out hypothesis (a) with the observations that the [OI]/[CII] line ratio increases for galaxies with higher F60/F100. This is contrary to the expectation that [OI] at 63 μ m should be more severely affected by extinction because it is at a shorter wavelength. Optical depth should also affect [OI] 63 μ m line more strongly because OI exists deeper (to Av=10) in the interior of clouds than [CII]. Hypothesis (b) explains the slight decrease in L[CII]/LFIR seen in early type galaxies with low rates of star-formation and the lowest LFIR/LB in the sample. The dramatic fall in L[CII]/LFIR for the warmest and most actively star-forming galaxies is best explained by hypothesis (c). In galaxies with warmer dust, there is less cooling via the [CII] line, while [OI] remains a major coolant. This trend is qualitatively explained in PDR models by an increase in radiation field G0, which raises the dust temperature and the [OI]/[CII] line ratio.

  6. Cryogenic far-infrared Fabry-Perot etalon

    NASA Technical Reports Server (NTRS)

    Peterson, D. B.; Pickett, H. M.

    1991-01-01

    A small cryogenic Fabry-Perot etalon was fabricated for the far-infrared region. The design used freestanding metal meshes for the reflecting elements. Using a combination of gold-coated copper mesh on stainless steel. The spacing is reproduced to 1 part in 10 exp 6 with repeated cooling. The properties and methods used for alignment and calibration are presented.

  7. Far infrared polarimeter with very low instrumental polarization

    NASA Astrophysics Data System (ADS)

    Battistelli, Elia S.; De Petris, Marco; Lamagna, Luca; Maoli, Roberto; Melchiorri, Francesco; Palladino, Emilia; Savini, Giorgio; Mauskopf, Philip D.; Orlando, Angiola

    2003-02-01

    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).

  8. Anomalous dispersion and the pumping of far infrared (FIR) lasers

    NASA Technical Reports Server (NTRS)

    Lawandy, N. M.

    1978-01-01

    It is shown that the anomalous dispersion at the pump transition in molecular far-infrared lasers (FIR) can lead to sizable focusing and defocusing effects. Criteria for beam spreading and trapping are considered with CH2F as an example.

  9. Arrays of Bolometers for Far-infrared and Submillimeter Astronomy

    NASA Astrophysics Data System (ADS)

    Chuss, D. T.; Allen, C. A.; Babu, S.; Benford, D. J.; Dotson, J. L.; Dowell, C. D.; Jhabvala, M.; Harper, D. A.; Moseley, S. Harvey; Silverberg, R. F.; Staguhn, J. G.; Voellmer, G.; Wollack, E. J.

    We describe 12 x 32 arrays of semiconducting cryogenic bolometers designed for use in far-infrared and submillimeter cameras. These 12 x 32 arrays are constructed from 1 x 32 monolithic pop-up detectors developed at NASA Goddard Space Flight Center. The pop-up technology allows the construction of large arrays with high filling factors that provide efficient use of space in the focal planes of far-infrared and submillimeter astronomical instruments. This directly leads to a significant decrease in integration time. The prototype array is currently operating in the second generation Submillimeter High Angular Resolution Camera (SHARC II), a facility instrument in use at the Caltech Submillimeter Observatory (CSO). The elements of this array employ a bismuth absorber coating and quarter wave backshort to optimize the bolometer absorption for passbands centered at 350 and 450 microns. A second array is to be installed in the High-resolution Airborne Widebandwidth Camera (HAWC), a far-infrared imaging camera for the Stratospheric Observatory for Infrared Astronomy (SOFIA). This array has been completed and is now awaiting integration into the HAWC test cryostat. HAWC is scheduled for commissioning in 2005. The HAWC array employs titanium-gold absorbers and is optimized for uniform absorption from 40 to 300 microns to accommodate all four of its far-infrared passbands. We describe the details of the HAWC array construction including the mechanical design and electrical characterization of the constituent linear arrays.

  10. Molecular cloud photoevaporation and far-infrared line emission

    NASA Astrophysics Data System (ADS)

    Vallini, L.; Ferrara, A.; Pallottini, A.; Gallerani, S.

    2017-05-01

    With the aim of improving predictions on far-infrared (FIR) line emission from Giant Molecular Clouds (GMCs), we study the effects of photoevaporation (PE) produced by external far-ultraviolet (FUV) and ionizing (extreme-ultraviolet) radiation on GMC structure. We consider three different GMCs with mass in the range MGMC = 103-106 M⊙. Our model includes (i) an observationally based inhomogeneous GMC density field, and (ii) its time evolution during the PE process. In the fiducial case (MGMC ≈ 105 M⊙), the PE time (tpe) increases from 1 to 30 Myr for gas metallicity Z = 0.05-1 Z⊙, respectively. Next, we compute the time-dependent luminosity of key FIR lines tracing the neutral and ionized gas layers of the GMCs, ([C ii] at 158 μm, [O iii] at 88 μm) as a function of G0, and Z until complete PE at tpe. We find that the specific [C ii] luminosity is almost independent of the GMC model within the survival time of the cloud. Stronger FUV fluxes produce higher [C ii] and [O iii] luminosities, however, lasting for progressively shorter times. At Z = Z⊙, the [C ii] emission is maximized (L_{C II} ≈ 10^4 {L_{{⊙}}} for the fiducial model) for t < 1 Myr and log G0 ≥ 3. Noticeably, and consistently with the recent detection by Inoue et al. of a galaxy at redshift z ≈ 7.2, for Z ≤ 0.2 Z⊙, the [O iii] line might outshine [C ii] emission by up to ≈1000 times. We conclude that the [O iii] line is a key diagnostic of low-metallicity interstellar medium, especially in galaxies with very young stellar populations.

  11. Astronomical polarization studies at radio and infrared wavelengths. Part 2: Far infrared polarization of dust clouds

    NASA Technical Reports Server (NTRS)

    Dennison, B. K.

    1976-01-01

    Far infrared polarization of dust clouds is examined. The recently observed 10 micron polarization of the Orion Nebula and the Galactic Center suggests that far infrared polarization may be found in these objects. Estimates are made of the degree of far infrared polarization that may exist in the Orion Nebula. An attempt to observe far infrared polarization from the Orion Nebula was carried out.

  12. Io: Heat Flow from Dark Volcanic Fields

    NASA Astrophysics Data System (ADS)

    Veeder, G. J.; Matson, D. L.; Davies, A. G.; Johnson, T. V.

    2008-03-01

    We focus on the heat flow contribution from dark volcanic fields on Io. These are concentrated in the anti-Loki hemisphere. We use the areas and estimated effective temperatures of dark flucti to derive their total power.

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

    NASA Technical Reports Server (NTRS)

    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.

  14. A balloon-borne 102-cm telescope for far-infrared astronomy

    NASA Astrophysics Data System (ADS)

    Fazio, Giovanni G.

    1990-12-01

    In the early 1970's, the Smithsonian Astrophysical Observatory and the University of Arizona engaged in a cooperative program to develop a balloon-borne 102-cm telescope capable of carrying out far infrared (40 to 250 micron) observations of astronomical interest above the earth's atmosphere. Since 1972, the telescope has flown and successfully recovered a total of nineteen times. Thirteen of the flights produced high-quality astronomical data, resulting in more than 92.5 hours of photometric and spectroscopic observations of numerous objects, such as H 2 regions, dark clouds, molecular clouds, a planetary nebula, a galaxy, the galactic center, the planets, and an asteroid. From the launch site in Palestine, Texas, sources as far south as -50 degrees declination were observed. The balloon-borne telescope was one of the most sensitive instruments ever used for observation in the far infrared region of the spectrum. It was most productive in producing high resolution maps of large areas (typically square degrees) centered on known H 2 regions, molecular clouds, and dark cloud complexes. In many cases, these scans produced the first far infrared maps of these regions, and many new sources were discovered. The results have led to a better understanding of the distribution of gas and dust in these regions, the evolution of H 2 regions, and the processes of star formation in giant molecular clouds. The following topics are presented: (1) the focal plane instrumentation; (2) the history and flight record; (3) scientific results and publications; (4) eduational aspects; and (5) future planes.

  15. A balloon-borne 102-cm telescope for far-infrared astronomy

    NASA Technical Reports Server (NTRS)

    Fazio, Giovanni G.

    1990-01-01

    In the early 1970's, the Smithsonian Astrophysical Observatory and the University of Arizona engaged in a cooperative program to develop a balloon-borne 102-cm telescope capable of carrying out far infrared (40 to 250 micron) observations of astronomical interest above the earth's atmosphere. Since 1972, the telescope has flown and successfully recovered a total of nineteen times. Thirteen of the flights produced high-quality astronomical data, resulting in more than 92.5 hours of photometric and spectroscopic observations of numerous objects, such as H 2 regions, dark clouds, molecular clouds, a planetary nebula, a galaxy, the galactic center, the planets, and an asteroid. From the launch site in Palestine, Texas, sources as far south as -50 degrees declination were observed. The balloon-borne telescope was one of the most sensitive instruments ever used for observation in the far infrared region of the spectrum. It was most productive in producing high resolution maps of large areas (typically square degrees) centered on known H 2 regions, molecular clouds, and dark cloud complexes. In many cases, these scans produced the first far infrared maps of these regions, and many new sources were discovered. The results have led to a better understanding of the distribution of gas and dust in these regions, the evolution of H 2 regions, and the processes of star formation in giant molecular clouds. The following topics are presented: (1) the focal plane instrumentation; (2) the history and flight record; (3) scientific results and publications; (4) eduational aspects; and (5) future planes.

  16. Kinetic inductance detectors for far-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Barlis, A.; Aguirre, J.; Stevenson, T.

    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 (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.

  17. Science with High Spatial Resolution Far-Infrared Data

    NASA Technical Reports Server (NTRS)

    Terebey, Susan (Editor); Mazzarella, Joseph M. (Editor)

    1994-01-01

    The goal of this workshop was to discuss new science and techniques relevant to high spatial resolution processing of far-infrared data, with particular focus on high resolution processing of IRAS data. Users of the maximum correlation method, maximum entropy, and other resolution enhancement algorithms applicable to far-infrared data gathered at the Infrared Processing and Analysis Center (IPAC) for two days in June 1993 to compare techniques and discuss new results. During a special session on the third day, interested astronomers were introduced to IRAS HIRES processing, which is IPAC's implementation of the maximum correlation method to the IRAS data. Topics discussed during the workshop included: (1) image reconstruction; (2) random noise; (3) imagery; (4) interacting galaxies; (5) spiral galaxies; (6) galactic dust and elliptical galaxies; (7) star formation in Seyfert galaxies; (8) wavelet analysis; and (9) supernova remnants.

  18. [Anomalous absorption and a qualified far infrared spectrum].

    PubMed

    Hu, Yan-qin; Chen, Yu-jing; Li, Hui-hua; Wang, Hai-shui

    2012-02-01

    The ideal 100% line could not be obtained when the content of water vapor in the spectrometer is constant but high during the whole procedure of a far-infrared spectrum collection. This result indicates that anomalous absorption phenomenon takes place in high relative humidity atmosphere. In the present paper, the influences of the relative humidity of ambient air and spectral resolution on anomalous absorption were studied. It was found that both decreasing the water vapor content in the spectrometer and adopting low spectral resolution are effective methods to avoid anomalous absorption. Furthermore, the water vapor bands can be eliminated by "dry air and wet air titration" in the fluctuant humidity. This provides us a quick and economic method to obtain a qualified far infrared spectrum conveniently. It should be noticed that the working condition for "dry air and wet air titration" is low relative humidity to prevent water vapor abnormal absorption.

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

    NASA Technical Reports Server (NTRS)

    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.

  20. Smithsonian stratospheric far-infrared spectrometer and data reduction system

    NASA Technical Reports Server (NTRS)

    Johnson, D. G.; Jucks, K. W.; Traub, W. A.; Chance, K. V.

    1995-01-01

    The Smithsonian far-infrared spectrometer (FIRS) is a remote sensing Fourier transform spectrometer that measures the mid- and far-infrared thermal emission spectrum of the stratosphere from balloon and aircraft platforms. The spectrometer has had nine successful balloon flights from 1987 to 1994, flying at float altitudes of 36 - 39 km and collecting 131 hours of midlatitude stratospheric limb spectra. The spectrometer also flew on a NASA CD-8 aircraft, as part of the second Airborne Arctic Stratospheric Expedition (AASE-2), collecting 140 hours of overhead spectra at latitudes ranging from the equator to the north pole. We present here a brief description of the instrument, a discussion of data reduction procedures, an estimation of both random and systematic errors, an outline of the procedure for retrieving mixing ratio profiles, and an explanation of the method of deriving temperature and pressure from the far- and mid-infrared spectra.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Using Guide Wavelengths to Assess Far-Infrared Laser Emissions

    NASA Astrophysics Data System (ADS)

    DeShano, B.; Olivier, K.; Cain, B.; Zink, L. R.; Jackson, M.

    2014-09-01

    An optically pumped molecular laser system with a transverse excitation scheme has been used to observe 77 guide wavelengths associated with the modes of an oversized waveguide laser resonator. These guide wavelengths, spanning from 102.6 to 990.6 μm, were generated by a variety of lasing media, including methanol along with several symmetric- and asymmetric-top molecules. The guide wavelengths displayed several consistent characteristics when compared with their respective fundamental laser emissions: their wavelengths were about 0.47 % larger and their relative powers were at least a factor of ten weaker. The properties of these guide wavelengths were used to assess frequency and wavelength measurements associated with known far-infrared laser emissions. For several of these laser emissions, this prompted a reinvestigation and subsequent revision of their measured values. Five far-infrared laser frequencies were also measured for the first time.

  3. Using Guide Wavelengths to Assess Far-Infrared Laser Emissions

    NASA Astrophysics Data System (ADS)

    DeShano, B.; Olivier, K.; Cain, B.; Zink, L. R.; Jackson, M.

    2015-01-01

    An optically pumped molecular laser system with a transverse excitation scheme has been used to observe 77 guide wavelengths associated with the modes of an oversized waveguide laser resonator. These guide wavelengths, spanning from 102.6 to 990.6 μm, were generated by a variety of lasing media, including methanol along with several symmetric- and asymmetric-top molecules. The guide wavelengths displayed several consistent characteristics when compared with their respective fundamental laser emissions: their wavelengths were about 0.47 % larger and their relative powers were at least a factor of ten weaker. The properties of these guide wavelengths were used to assess frequency and wavelength measurements associated with known far-infrared laser emissions. For several of these laser emissions, this prompted a reinvestigation and subsequent revision of their measured values. Five far-infrared laser frequencies were also measured for the first time.

  4. Efficient far-infrared thermal bremsstrahlung radiation from a heterojunction bipolar transistor

    SciTech Connect

    Chung, Pei-Kang; Yen, Shun-Tung

    2015-08-28

    We investigate the far-infrared thermal radiation properties of a heterojunction bipolar transistor. The device conveniently provides a high electric field for electrons to heat the lattice and the electron gas in a background with ions embedded. Because of very high effective temperature of the electron gas in the collector, the electron-ion bremsstrahlung makes efficient the thermal radiation in the far-infrared region. The transistor can yield a radiation power of 0.1 mW with the spectral region between 2 and 75 THz and a power conversion efficiency of 6 × 10{sup −4}. Such output contains a power of 20 μW in the low-frequency part (2–20 THz) of the spectrum.

  5. Stacked Metal Silicide/Silicon Far-Infrared Detectors

    NASA Technical Reports Server (NTRS)

    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.

  6. Arrays of Bolometers for Far-infrared and Submillimeter Astronomy

    NASA Technical Reports Server (NTRS)

    Chuss, D. T.; Allen, C. A.; Babu, S.; Casey, S.; Dotson, J. L.; Dowell, C. D.; Jhabvala, M.; Harper, D. A.; Moseley, S. H.; Silverberg, R. F.

    2004-01-01

    We describe 12 x 32 arrays of semiconducting cryogenic bolometers designed for use in far-infrared and submillimeter cameras. These 12 x 32 arrays are constructed from 1 x 32 monolithic pop-up detectors developed at NASA Goddard Space Flight Center. The pop-up technology allows the construction of large arrays with high filling factors that provide efficient use of space in the focal planes of far-infrared and submillimeter astronomical instruments. This directly leads to a significant decrease in observing time. The prototype array is currently operating in SHARC II, a facility instrument in use at the Caltech Submillimeter Observatory (CSO). The elements of this array employ a bismuth absorber coating and quarter wave backshort to optimize the bolometer absorption for a passband centered at 350 microns. However, this resonant structure also provides good bolometer performance at 450 and 850 microns, the two additional SHARC II passbands. A second array is to be installed in the High-resolution Airborne Widebandwidth Camera (HAWC), a far-infrared imaging camera for the Stratospheric Observatory for Infrared Astronomy (SOFIA). This array is currently in the final stage of construction, and its completion is expected in early 2004. HAWC is scheduled for commissioning in 2005. The HAWC array employs titanium-gold absorbers and is optimized for uniform absorption from 40 to 300 microns to accommodate all four of its far-infrared passbands. We describe the details of the array construction including the mechanical design and electrical characterization of the constituent linear arrays, comparing the SHARC II and HAWC cases. We also summarize the overall characteristics of the final two-dimensional arrays. Finally, we show examples of array performance in the form of images obtained with SHARC II.

  7. The cosmic far-infrared background at high galactic latitudes

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; Puget, J. L.; Fazio, G. G.

    1976-01-01

    Far-infrared background fluxes from various cosmic sources are predicted. These fluxes lie near the high frequency side of the blackbody radiation spectrum. These sources could account for a significant fraction of the background radiation at frequencies above 400 GHz which might be misinterpreted as a comptonization distortion of the blackbody radiation. Particular attention is paid to the possible contributions from external galaxies, rich clusters of galaxies and from galactic dust emission.

  8. Arrays of Bolometers for Far-infrared and Submillimeter Astronomy

    NASA Technical Reports Server (NTRS)

    Chuss, D. T.; Allen, C. A.; Babu, S.; Casey, S.; Dotson, J. L.; Dowell, C. D.; Jhabvala, M.; Harper, D. A.; Moseley, S. H.; Silverberg, R. F.

    2004-01-01

    We describe 12 x 32 arrays of semiconducting cryogenic bolometers designed for use in far-infrared and submillimeter cameras. These 12 x 32 arrays are constructed from 1 x 32 monolithic pop-up detectors developed at NASA Goddard Space Flight Center. The pop-up technology allows the construction of large arrays with high filling factors that provide efficient use of space in the focal planes of far-infrared and submillimeter astronomical instruments. This directly leads to a significant decrease in observing time. The prototype array is currently operating in SHARC II, a facility instrument in use at the Caltech Submillimeter Observatory (CSO). The elements of this array employ a bismuth absorber coating and quarter wave backshort to optimize the bolometer absorption for a passband centered at 350 microns. However, this resonant structure also provides good bolometer performance at 450 and 850 microns, the two additional SHARC II passbands. A second array is to be installed in the High-resolution Airborne Widebandwidth Camera (HAWC), a far-infrared imaging camera for the Stratospheric Observatory for Infrared Astronomy (SOFIA). This array is currently in the final stage of construction, and its completion is expected in early 2004. HAWC is scheduled for commissioning in 2005. The HAWC array employs titanium-gold absorbers and is optimized for uniform absorption from 40 to 300 microns to accommodate all four of its far-infrared passbands. We describe the details of the array construction including the mechanical design and electrical characterization of the constituent linear arrays, comparing the SHARC II and HAWC cases. We also summarize the overall characteristics of the final two-dimensional arrays. Finally, we show examples of array performance in the form of images obtained with SHARC II.

  9. The Far-infrared Rotational Spectrum of Ethylene Oxide

    NASA Astrophysics Data System (ADS)

    Medcraft, Chris; Thompson, Christopher D.; Robertson, Evan G.; Appadoo, Dominique R. T.; McNaughton, Don

    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-1 were assigned, with J max = 64, expanding upon previous studies that had recorded spectra up to 12 cm-1, J 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-1.

  10. Community Plan for Far-Infrared/Submillimeter Space Astronomy

    NASA Technical Reports Server (NTRS)

    Ade, Peter; Akeson, Rachel; Ali, Shafinaz; Amato, Michael; Arendt, Richard; Baker, Charles; Benford, Dominic; Blain, Andrew; Bock, James; Borne, Kirk

    2004-01-01

    This paper represents the consensus view of the 124 participants in the Second Workshop on New Concepts for Far-Infrared/Submillimeter Space Astronomy.We recommend that NASA pursue the vision for far-IR astronomy outlined in the NAS Decadal Survey, which said: A rational coordinated program for space optical and infrared astronomy would build on the experience gained with NGST1 to construct [a JWST-scale filled-aperture far-IR telescope SAFIR, and then ultimately, in the decade 2010 to 2020, build on the SAFIR, TPF, and SIM experience to assemble a space-based, far-infrared interferometer. SAFIR will study star formation in the young universe, the buildup of elements heavier than hydrogen over cosmic history, the process of galaxy formation, and the early phases of star formation, which occur behind a veil of dust that precludes detection at mid IR and shorter wavelengths. The far-infrared interferometer will resolve distant galaxies to study protogalaxy interactions and mergers and the processes that led to enhanced star formation activity and the formation of Active Galactic Nuclei, and will resolve protostars and debris disks in our Galaxy to study how stars and planetary systems form.

  11. ISO Far-Infrared Spectroscopic Observations of Jupiter

    NASA Astrophysics Data System (ADS)

    Burgdorf, M. J.; Encrenaz, Th.; Feuchtgruber, H.; Davis, G. R.; Fouchet, Th.; Gautier, D.; Lellouch, E.; Orton, G. S.; Sidher, S. D.

    2001-07-01

    We present the far-infrared spectrum of Jupiter that was measured with the Short and Long Wavelength Spectrometers (SWS and LWS) aboard the Infrared Space Observatory (ISO). The region between 38 and 44 microns was observed in grating mode, where the SWS provides a spectral resolution of about 1300. For longer waves up to 197 microns the LWS-FP (Fabry-Perot) was used to achieve a resolution of several thousand. The observations were made between 23 and 26 May 1997 during ISO's revolutions 554, 556 and 557. The Jovian spectrum in the far-infrared is compared to an atmospheric radiative transfer model using expected values for the vertical profiles of the atmospheric constituents. Rotational transitions of ammonia and phosphine are responsible for the absorption features observed: Strong ammonia absorption manifolds are obvious against the background continuum slope, appearing at 39, 42, 46, 51, 56, 63, 72, 84, 100 and 125 microns in both the data and the model. Also PH3 features are present at the expected wavelengths of 113 and 141 microns in both the data and the model. This is the first time that most of these far-infrared features have been detected. The ISO observations are therefore of interest for the preparation of the planned submillimeter studies of the atmospheres of the Jovian planets with FIRST.

  12. Flight performance of the Far-Infrared Line Mapper (FILM)

    NASA Astrophysics Data System (ADS)

    Shibai, Hiroshi; Nakagawa, Takao; Makiuti, Sin'itirou; Matsuhara, Hideo; Hiromoto, Norihisa; Okumura, Ken-Ichi; Doi, Yasuo; Toya, Takanao; Okuda, Haruyuki

    1996-10-01

    The far-infrared line mapper (FILM) is a far-infrared spectrometer and in one of four focal plane instruments of the infrared telescope in space (IRTS), FILM was designed for wide area intensity mapping of far-infrared emission from interstellar gas and dust in the galaxy. The targets are the [CII] 158 micrometer line of the ionized carbon, the [OI] 63 micrometer line of the oxygen atom, and the continuum emission at 155 and 160 micrometer from the interstellar dust grain. A cylindrically concave varied line-space grating and a linear array of stressed Ge:Ga were successfully developed and allowed us to make a compact spectrometer compatible to severe limitations of the small cryogenic telescope. The IRTS, onboard the space flyer unit (SFU), was launched by a HII rocket on March 18, 1995 and was recovered by a STS on January 13, 1996. The FILM worked very well during four weeks allocated for the IRTS observation and produced a lot of valuable data. The sensitivity and the spatial resolution for the [CII] line are an order of magnitude better than the previous work.

  13. Far-Infrared Water Line Emissions from Circumstellar Outflows

    NASA Technical Reports Server (NTRS)

    Chen, Wesley; Neufeld, David A.

    1995-01-01

    We have modeled the far-infrared water line emission expected from circumstellar outflows from oxygen-rich late-type stars, as a function of the mass-loss rate and the terminal outflow velocity. For each mass-loss rate and terminal outflow velocity considered, we computed self-consistently the gas density, temperature, outflow velocity, and water abundance as a function of distance from the star. We then used an escape probability method to solve for the equilibrium level populations of 80 rotational states of water and thereby obtained predictions for the luminosity of a large number of far-infrared rotational transitions of water. In common with previous models, our model predicts that water will be copiously produced in the warm circumstellar gas and that water rotational emission will dominate the radiative cooling. However, our use of a realistic radiative cooling function for water leads to a lower gas temperature than that predicted in previous models. Our predictions for the far-infrared water line luminosities are consequently significantly smaller than those obtained in previous studies. Observations to be carried out by the Infrared Space Observatory will provide a crucial test of the models presented here.

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    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 ≳ 6 become increasingly difficult because of instrumental limitations and the paucity of background quasars. With the advent of Atacama Large Millimeter/submillimeter Array (ALMA), far-infrared emission lines provide a novel tool to study early metal enrichment. Among these, the [C II] line at 157.74 μm is the most luminous line emitted by the interstellar medium of galaxies. It can also resonant scatter comic microwave background (CMB) photons inducing characteristic intensity fluctuations (ΔI/ICMB) near the peak of the CMB spectrum, thus allowing to probe the low-density IGM. We compute both [C II] galaxy emission and metal-induced CMB fluctuations at z ˜ 6 by using adaptive mesh refinement cosmological hydrodynamical simulations and produce mock observations to be directly compared with ALMA Band 6 data (νobs ˜ 272 GHz). The [C II] line flux is correlated with MUV as log (F_peak/μ Jy)= -27.205 -2.253 M_UV -0.038 M_UV^2. Such relation is in very good agreement with recent ALMA observations of MUV < -20 galaxies by e.g. Maiolino et al. and Capak et al. We predict that a MUV = -19 (MUV = -18) galaxy can be detected at 4σ in ≃40 (2000) h, respectively. CMB resonant scattering can produce ≃ ± 0.1 μJy/beam emission/absorptions features that are very challenging to be detected with current facilities. The best strategy to detect these signals consists in the stacking of deep ALMA observations pointing fields with known MUV ≃ -19 galaxies. This would allow to simultaneously detect both [C II] emission from galactic reionization sources and CMB fluctuations produced by z ˜ 6 metals.

  15. Large Format Arrays for Far Infrared and Millimeter Astronomy

    NASA Technical Reports Server (NTRS)

    Moseley, Harvey

    2004-01-01

    Some of the most compelling questions in modem astronomy are best addressed with submillimeter and millimeter observations. The question of the role of inflation in the early evolution of the universe is best addressed with large sensitive arrays of millimeter polarimeters. The study of the first generations of galaxies requires sensitive submillimeter imaging, which can help us to understand the history of energy release and nucleosynthesis in the universe. Our ability to address these questions is dramatically increasing, driven by dramatic steps in the sensitivity and size of available detector arrays. While the MIPS instrument on the SIRTF mission will revolutionize far infrared astronomy with its 1024 element array of photoconductors, thermal detectors remain the dominant technology for submillimeter and millimeter imaging and polarimetry. The last decade has seen the deployment of increasingly large arrays of bolometers, ranging from the 48 element arrays deployed on the KAO in the late 198Os, to the SHARC and SCUBA arrays in the 1990s. The past years have seen the deployment of a new generation of larger detector arrays in SHARC II (384 channels) and Bolocam (144 channels). These detectors are in operation and are beginning to make significant impacts on the field. Arrays of sensitive submillimeter bolometers on the SPIRE instrument on Herschel will allow the first large areas surveys of the sky, providing important insight into the evolution of galaxies. The next generation of detectors, led by SCUBA II, will increase the focal scale of these instruments by an order of magnitude. Two major missions are being planned by NASA for which further development of long wavelength detectors is essential, The SAFlR mission, a 10-m class telescope with large arrays of background limited detectors, will extend our reach into the epoch of initial galaxy formation. A major goal of modem cosmology is to test the inflationary paradigm in the early evolution of the universe

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

    PubMed

    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.

  17. High resolution far-infrared survey of A section of the galactic plane. I. The nature of the sources

    SciTech Connect

    Jaffe, D.T.; Stier, M.T.; Fazio, G.G.

    1982-01-15

    We have surveyed a 7.5 deg/sup 2/ portion of the galactic plane between l/sup II/ = 10/sup 0/ and l/sup II/ = 16/sup 0/ at 70 ..mu..m with a 1' beam. We present far-infrared, radio continuum, and /sup 12/CO and /sup 13/CO line observations of the 42 far-infrared sources in the survey region. The sources range in luminosity from 4 x 10/sup 3/ to 3 x 10/sup 6/ L/sub sun/. Most are associated with /sup 12/CO peaks. More than half of the sources have associated H/sub 2/O maser emission. Half have associated radio continuum emission at a limit of 100 mJy. Eight sources have radio emission at weaker levels. In a number of cases, the far-infrared source is smaller than its associated radio source. This difference can be explained in the context of the ''blister'' picture of H II regions. One group of sources emits many fewer Lyman continuum photons than expected, given the far-infrared luminosities. We examine a number of possible reasons for this and conclude that the most reasonable explanation is that clusters of early type stars rather than single stars excite the far-infrared sources. We examine the energetics in the molecular clouds surrounding the infrared sources and conclude that the sources could supply the energy to explain the observed temperature structure and velocity field in the molecular gas.

  18. Investigation of jewelry powders radiating far-infrared rays and the biological effects on human skin.

    PubMed

    Yoo, B H; Park, C M; Oh, T J; Han, S H; Kang, H H; Chang, I S

    2002-01-01

    Far-infrared rays have certain kinds of effects on the human body, especially on skin, blood circulation, and skin cell vitalizing. Some jewelry powders radiate far-infrared rays. Jade has powerful far-infrared ray radiation, and tourmaline has pyroelectric and piezoelectric properties and radiated far-infrared rays. The jewelry powders (fine powdered jade and tourmaline powders) were screened by far-infrared rays for radiation properties and tested for the effects of far-infrared rays on the human skin by temperature observation using an infrared thermal analyzer.

  19. Description of dark energy and dark matter by vector fields

    NASA Astrophysics Data System (ADS)

    Meierovich, Boris E.

    A simple Lagrangian (with squared covariant divergence of a vector field as a kinetic term) turned out an adequate tool for oscopic description of dark sector. The zero-mass field acts as the dark energy. Its energy-momentum tensor is a simple additive to the cosmological constant. Space-like and time-like massive vector fields describe two different forms of dark matter. The space-like field is attractive. It is responsible for the observed plateau in galaxy rotation curves. The time-like massive field displays repulsive elasticity. In balance with dark energy and ordinary matter it provides a four-parametric diversity of regular solutions of the Einstein equations describing different possible cosmological and oscillating non-singular scenarios of evolution of the Universe. In particular, the singular "big bang" turns into a regular inflation-like transition from contraction to expansion with accelerated expansion at late times. The fine-tuned Friedman-Robertson-Walker singular solution is a particular limiting case at the boundary of existence of regular oscillating solutions (in the absence of vector fields). The simplicity of the general covariant expression for the energy-momentum tensor allows analyzing the main properties of the dark sector analytically, avoiding unnecessary model assumptions.

  20. Technology Needs for Far-Infrared, Submillimeter, and Millimeter Missions

    NASA Technical Reports Server (NTRS)

    Moseley, S. Harvey

    2004-01-01

    SAFIR will: Study the important and relatively unexplored region of the spectrum between 30 and 300 m; Enable the study of galaxy formation and the earliest stage of star formation by revealing regions too enshrouded by dust to be studied by NGST; Be more than 100 times as sensitive as SIRTF or the European [Herschel] mission.SAFIR is projected to cost around $600M total. The decadal review committee recommends that $100M be allocated in this decade to start the SAFIR project, and that additional technology developments be funded separately: Far-Infrared Array Development ($10M ) Refrigerators ($50M ) Large, Lightweight Optics ($80M ). Current developments are also described.

  1. Submillimeter and Far-Infrared Dielectric Properties of Thin Films

    NASA Technical Reports Server (NTRS)

    Cataldo, Giuseppe; Wollack, Edward J.

    2016-01-01

    The complex dielectric function enables the study of a material's refractive and absorptive properties and provides information on a material's potential for practical application. Commonly employed line shape profile functions from the literature are briefly surveyed and their suitability for representation of dielectric material properties are discussed. An analysis approach to derive a material's complex dielectric function from observed transmittance spectra in the far-infrared and submillimeter regimes is presented. The underlying model employed satisfies the requirements set by the Kramers-Kronig relations. The dielectric function parameters derived from this approach typically reproduce the observed transmittance spectra with an accuracy of less than 4%.

  2. A Broadband Micro-Machined Far-Infrared Absorber

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    The experimental investigation of a broadband far-infrared meta-material absorber is described. The observed absorptance is greater than 0.95 from 1 to 20 terahertz (300-15 microns) over a temperature range spanning 5-300 degrees Kelvin. The meta-material, realized from an array of tapers approximately 100 microns 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.

  3. Submillimeter and Far-Infrared Dielectric Properties of Thin Films

    NASA Technical Reports Server (NTRS)

    Cataldo, Giuseppe; Wollack, Edward J.

    2016-01-01

    The complex dielectric function enables the study of a material's refractive and absorptive properties and provides information on a material's potential for practical application. Commonly employed line shape profile functions from the literature are briefly surveyed and their suitability for representation of dielectric material properties are discussed. An analysis approach to derive a material's complex dielectric function from observed transmittance spectra in the far-infrared and submillimeter regimes is presented. The underlying model employed satisfies the requirements set by the Kramers-Kronig relations. The dielectric function parameters derived from this approach typically reproduce the observed transmittance spectra with an accuracy of less than 4%.

  4. A broadband micro-machined far-infrared absorber

    NASA Astrophysics Data System (ADS)

    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.

  5. W3 North: Far-infrared and radio molecular observations

    NASA Technical Reports Server (NTRS)

    Thronson, H. A., Jr.; Schwartz, P. R.; Smith, H. A.; Lada, C. J.; Glaccum, W.; Harper, D. A.

    1984-01-01

    The W3 North (G133.8 + 1.4) source is the northernmost member of a string of active star forming regions that marks the western boundary of the giant HII region W4. Far infrared and radio observations of molecular CO were made of the W3 star forming region. The W3 North object shows extended dust and gas emission which suggests a fairly advanced disruption of a molecular cloud. An estimate of the age of the embedded HII region is given, and emission maps of the W3 object are presented. The W3 North source may be the oldest object among the W3 complex of sources.

  6. A Broadband Micro-Machined Far-Infrared Absorber

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    The experimental investigation of a broadband far-infrared meta-material absorber is described. The observed absorptance is greater than 0.95 from 1 to 20 terahertz (300-15 microns) over a temperature range spanning 5-300 degrees Kelvin. The meta-material, realized from an array of tapers approximately 100 microns 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. Transmission measurements of selected liquids in the far infrared

    SciTech Connect

    Walker, M.A.; Richards, R.K.; Hutchinson, D.P.

    1985-11-01

    Measurements were taken of the transmission of 0.119 mm radiation through 22 liquids using a variable length absorption cell for the preparation of the design of an acousto-optic modulator. Seven of these liquids were then selected to be tested at wavelengths of 0.185 mm, 0.307 mm, and 0.447 mm. It was found that a light grade of mineral oil proved to have excellent transmission in the far-infrared (FIR) spectrum. We were able, from the data collected, to estimate the index of refraction of these liquids at wavelengths longer than 0.3 mm. 1 ref., 2 figs., 3 tabs.

  8. THE FAR-INFRARED ROTATIONAL SPECTRUM OF ETHYLENE OXIDE

    SciTech Connect

    Medcraft, Chris; Thompson, Christopher D.; McNaughton, Don; Robertson, Evan G.; Appadoo, Dominique R. T.

    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}.

  9. a Far Infrared Synchrotron-Based Investigation of 3-OXETANONE

    NASA Astrophysics Data System (ADS)

    Chen, Ziqiu; van Wijngaarden, Jennifer

    2011-06-01

    The four membered ester ring 3-oxetanone is a precursor for adding oxetane subunits into pharmaceuticals which then block metabolically exposed sites in the bioactive molecule without increasing its lipophilicity. The high resolution (0.00096 cmCm-1) rovibrational spectrum of 3-oxetanone was recorded for the first time using far infrared radiation from the Canadian Light Source (CLS) synchrotron facility coupled to a Bruker IFS125HR FTIR spectrometer. A total of six rotationally-resolved vibrational bands were observed between 360 and 1150 cmCm-1 at room temperature. The assignment of the dense spectrum is currently underway and the progress will be discussed in this talk.

  10. Far infrared edge photoresponse and persistent edge transport in an inverted InAs/GaSb heterostructure

    SciTech Connect

    Dyer, G. C.; Olson, B. V.; Hawkins, S. D.; Klem, J. F.; Shaner, E. A.; Pan, W.; Shi, X.

    2016-01-04

    Direct current (DC) transport and far infrared photoresponse were studied an InAs/GaSb double quantum well with an inverted band structure. The DC transport depends systematically upon the DC bias configuration and operating temperature. Surprisingly, it reveals robust edge conduction despite prevalent bulk transport in our device of macroscopic size. Under 180 GHz far infrared illumination at oblique incidence, we measured a strong photovoltaic response. We conclude that quantum spin Hall edge transport produces the observed transverse photovoltages. Overall, our experimental results support a hypothesis that the photoresponse arises from direct coupling of the incident radiation field to edge states.

  11. Halos of unified dark matter scalar field

    SciTech Connect

    Bertacca, Daniele; Bartolo, Nicola; Matarrese, Sabino E-mail: nicola.bartolo@pd.infn.it

    2008-05-15

    We investigate the static and spherically symmetric solutions of Einstein's equations for a scalar field with a non-canonical kinetic term, assumed to provide both the dark matter and dark energy components of the Universe. In particular, we give a prescription to obtain solutions (dark halos) whose rotation curve v{sub c}(r) is in good agreement with observational data. We show that there exist suitable scalar field Lagrangians that allow us to describe the cosmological background evolution and the static solutions with a single dark fluid.

  12. Tunable far infrared studies of molecular parameters in support of stratospheric measurements

    NASA Technical Reports Server (NTRS)

    Chance, K. V.; Nolt, Ira G.; Radostitz, J. V.; Park, K.

    1990-01-01

    The purpose of this research is to make precise, fully line-resolved measurements of molecular parameters that are necessary for the analysis of spectra obtained in far infrared field measurement programs. These measurements make it possible to accurately analyze the data from field measurements to obtain atmospheric concentration profiles of key trace gases involved in the ozone chemistry. The research objectives include: measurements of pressure broadening of molecular lines of OH, O2, O3, HCl, and H2O, their temperature dependence, and, when possible, the pressure-induced frequency shifts of the lines; measurements of line positions of radical species, such as HO2.

  13. Far-Infrared Line Emission from High Redshift Quasars

    NASA Technical Reports Server (NTRS)

    Benford, D. J.; Cox, P.; Hunter, T. R.; Malhotra, S.; Phillips, T. G.; Yun, M. S.

    2002-01-01

    Recent millimeter and submillimeter detections of line emission in high redshift objects have yielded new information and constraints on star formation at early epochs. Only CO transitions and atomic carbon transitions have been detected from these objects, yet bright far-infrared lines such as C+ at 158 microns and N+ at 205 microns should be fairly readily detectable when redshifted into a submillimeter atmospheric window. We have obtained upper limits for C+ emission &om two high redshift quasars, BR1202-0725 at z=4.69 and BRI1335-0415 at z=4.41. These limits show that the ratio of the C+ line luminosity to the total far-infrared luminosity is less than 0.0l%, ten times smaller than has been observed locally. Additionally, we have searched for emission in the N+ 205 micron line from the Cloverleaf quasar, H1413+117, and detected emission in CO J=7-6. The N+ emission is found to be below the amount predicted based on comparison to the only previous detection of this line, in the starburst galaxy M82.

  14. Far-Infrared Interferometric Telescope Experiment : I. Interferometer Optics

    NASA Astrophysics Data System (ADS)

    Kato, Eri; Shibai, Hiroshi; Kawada, Mitsunobu; Narita, Masanao; Matsuo, Taro; Ohkubo, Atsushi; Suzuki, Miki; Kanoh, Tetsuo; Yamamoto, Koudai; Fite Team

    We have developed a far-infrared interferometer (Far-Infrared Interferometric Telescope Experiment: FITE). It will be the first astronomical infrared interferometer working in space. FITE is a balloon-borne telescope, and operated in the stratosphere (the altitude of 35 km). The aim of the FITE project is to achieve a high spatial resolution of 1 arcsecond at the wavelength of 100 micrometers. FITE is a Michelson stellar interferometer, and is able to realize a long base line beyond the size of the collecting mirror by using four plane mirrors. The first flight is scheduled for November 2008 in Brazil, and the aim is to measure the interference fringes with a spatial resolution of 2.5 arcseconds. In order to achieve this, the two beams must be focused within 2.5 arcsecond accuracy in the imaging quality, within 10 arcsecond accuracy in the beam alignment and within 30 micrometers accuracy in the optical path length between the two beams. In order to archive these accuracies, the structural parts of the telescope were made of carbon-fiber reinforced plastics, which have very low thermal expansion coefficient and large Young's modulus. During observation of a target, the optical alignment is actively adjusted and the orientation of the telescope is stabilized by the three-axis control.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Bolometers for far-infrared and submillimetre astronomy

    NASA Astrophysics Data System (ADS)

    Griffin, M. J.

    2000-04-01

    Important scientific goals of far-infrared and submillimetre astronomy include measurements of anisotropies in the cosmic background radiation, deep imaging surveys for detection of high-red-shift galaxies, and imaging and spectroscopy of star formation regions and the interstellar medium in the milky way and nearby galaxies. Use of sensitive bolometer arrays leads to very large improvements in observing speed. Recent progress in the development of bolometric detector systems for ground-based and space-borne far-infrared and submillimetre astronomical observations is reviewed, including spider-web NTD bolometers, transition-edge superconducting sensors, and micromachined planar arrays of ion-implanted silicon bolometers. Future arrays may be based on planar absorbers without feedhorns, which offer potential advantages including more efficient use of space in the focal plane and improved instantaneous sampling of the telescope point spread function, but present challenges in suppression of stray light and RF interference. FIRST and Planck Surveyor are planned satellite missions involving passively cooled (~70K) telescopes, and bolometer array developments for these missions are described.

  17. Superconducting Microwave Resonator Arrays for Submillimeter/Far-Infrared Imaging

    NASA Astrophysics Data System (ADS)

    Noroozian, Omid

    Superconducting microwave resonators have the potential to revolutionize submillimeter and far-infrared astronomy, and with it our understanding of the universe. The field of low-temperature detector technology has reached a point where extremely sensitive devices like transition-edge sensors are now capable of detecting radiation limited by the background noise of the universe. However, the size of these detector arrays are limited to only a few thousand pixels. This is because of the cost and complexity of fabricating large-scale arrays of these detectors that can reach up to 10 lithographic levels on chip, and the complicated SQUID-based multiplexing circuitry and wiring for readout of each detector. In order to make substantial progress, next-generation ground-based telescopes such as CCAT or future space telescopes require focal planes with large-scale detector arrays of 104--10 6 pixels. Arrays using microwave kinetic inductance detectors (MKID) are a potential solution. These arrays can be easily made with a single layer of superconducting metal film deposited on a silicon substrate and pattered using conventional optical lithography. Furthermore, MKIDs are inherently multiplexable in the frequency domain, allowing ˜ 10 3 detectors to be read out using a single coaxial transmission line and cryogenic amplifier, drastically reducing cost and complexity. An MKID uses the change in the microwave surface impedance of a superconducting thin-film microresonator to detect photons. Absorption of photons in the superconductor breaks Cooper pairs into quasiparticles, changing the complex surface impedance, which results in a perturbation of resonator frequency and quality factor. For excitation and readout, the resonator is weakly coupled to a transmission line. The complex amplitude of a microwave probe signal tuned on-resonance and transmitted on the feedline past the resonator is perturbed as photons are absorbed in the superconductor. The perturbation can be

  18. A new approach to the radio-far infrared correlation for non-calorimeter galaxies.

    NASA Astrophysics Data System (ADS)

    Niklas, S.; Beck, R.

    1997-04-01

    New radio continuum data for a sample of 74 spiral galaxies supports the calorimeter model of Voelk (1989A&A...218...67V) only for steep-spectrum, thin-disk, non-interacting objects which comprise =~30% of the sample. As the spectral indices correlate neither with far infrared surface brightness nor with average (equipartition) magnetic field strength, the data disagree with the model for non-calorimeter galaxies of Helou & Bicay (1993ApJ...415...93H). We are able to explain the radio - far infrared correlation for non-calorimeter galaxies, globally and also on kiloparsec scales within galaxies, with the help of two basic relations with the average volume density of the gas as the primary factor. Firstly, there is strong evidence that the strength of the equipartition magnetic field is correlated with the volume density ρ of the (almost) neutral gas, following a power law with an exponent of m=0.48+/-0.05 for the galactic averages of our sample. Secondly, taking the thermal radio emissivity as an indicator of the average star-formation rate (SFR), we obtain a `Schmidt law' (SFR{prop.to}ρ^n^) with n=1.4+/-0.3. The FIR luminosity is linearly related to SFR. Finally, we assume equipartition between the energy densities of the magnetic field and of the cosmic rays which relates the synchrotron emissivity to the field strength. Combination of these relations leads to a radio - far infrared luminosity correlation with a power-law exponent of x=1.3+/-0.3, very close to what is observed (x=1.25+/-0.08). Forthcoming ISO satellite data can be used as a test of our approach.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

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

    2014-07-15

    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{sup −1} to 7000 cm{sup −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.

  2. Dark Matter in the Hubble Frontier Fields

    NASA Astrophysics Data System (ADS)

    Diego, J. M.

    2015-05-01

    We present results on the dark matter distribution of the Hubble Frontier Fields (HFF). The HFF represents the best collection of strong lensing data in merging clusters. We study the first two clusters from the HFF program using a free-form method that makes no assumptions about the mass distribution to reconstruct the dark matter that best fits the strong lensing data. Our reconstructed dark matter distributions exhibit some interesting features including very shallow profiles and possible offsets between the baryonic and dark matter distribution. For the first time, we find evidence that suggests that the strong lensing data seems to be sensitive to the mass of the X-ray plasma. Also, by analyzing the strong lensing in one individual galaxy we are able to constrain the shape of the dark matter halo around that galaxy. Our results support the standard models of dark matter and disfavours alternative models like MOND.

  3. Io: Heat flow from dark volcanic fields

    NASA Astrophysics Data System (ADS)

    Veeder, Glenn J.; Davies, Ashley Gerard; Matson, Dennis L.; Johnson, Torrence V.

    2009-11-01

    Dark flow fields on the jovian satellite Io are evidence of current or recent volcanic activity. We have examined the darkest volcanic fields and quantified their thermal emission in order to assess their contribution to Io's total heat flow. Loki Patera, the largest single source of heat flow on Io, is a convenient point of reference. We find that dark volcanic fields are more common in the hemisphere opposite Loki Patera and this large scale concentration is manifested as a maximum in the longitudinal distribution (near ˜200 °W), consistent with USGS global geologic mapping results. In spite of their relatively cool temperatures, dark volcanic fields contribute almost as much to Io's heat flow as Loki Patera itself because of their larger areal extent. As a group, dark volcanic fields provide an asymmetric component of ˜5% of Io's global heat flow or ˜5 × 10 12 W.

  4. Far-Infrared Extragalactic Surveys: Past, Present, and Future

    NASA Technical Reports Server (NTRS)

    Moseley, Samuel H., Jr.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    As much as one third of the luminosity of the local universe is emitted in the far infrared. In order to understand the history of energy release in the universe, it is crucial to characterize this rest-frame far-infrared contribution from the present back to the era of initial galaxy formation. Over the redshift range from 0 to 10, this energy is received in the 80 micrometers to 1 mm spectral region. In the 1980's the Infrared Astronomy Satellite (IRAS) all-sky survey provided the first comprehensive view of the far infrared emission from the local universe. The diffuse background measurements by Cosmic Background Explorer Satellite (COBE) have provided constraints on the integral contributions from the high redshift universe. In the past five years, submillimeter measurements made using the SCUBA instrument have revealed powerful high redshift sources. To develop a clear history of energy release in the universe, we need numbers and redshifts of representative populations of energetically important objects. The near future will bring the Space Infrared Telescope Facility Multiband Imaging Photometer (SIRTF)(MIPS) survey, which will cover about 100 square degrees at wavelengths out to 160 micrometers, providing a large sample of energetically important galaxies out to z of approx.3. In 2005, the Japanese IRIS survey will provide a 160 micrometers full sky survey, which will provide larger samples of the high z galaxy populations and will find intrinsically rare high luminosity objects. The SPIRE instrument on the FIRST facility will extend these surveys to longer wavelengths, providing a view of the universe at higher redshifts in three spectral bands. A concept for an all-sky submillimeter survey is under development, called the Survey of Infrared Cosmic Evolution (SIRCE). With a 2 m cryogenic telescope, it can map the entire sky to the confusion limit in the 100 to 500 micrometers range in six months. This survey will provide photometric redshifts, number

  5. A Stark-tuned, far-infrared laser for high frequency plasma diagnostics

    SciTech Connect

    Mansfield, D.K.; Vocaturo, M.; Guttadora, L.; Rockmore, M.; Micai, K. . Plasma Physics Lab.); Krug, P.A. . School of Physics)

    1992-03-01

    A Stark-tuned optically pumped far-infrared methanol laser operating at 119 micrometers has been built. The laser is designed to operate at high power while exhibiting a well-separated Stark doublet. At a pump power of 65 Watts and electric field of 1 kV/cm the laser has delivered over 100 mW c.w. while exhibiting a frequency splitting of 34 MHz. These parameters indicate that this laser would be suitable for use in the present generation of modulated interferometers on large thermonuclear plasma devices. The achieved modulation frequency is more than an order of magnitude higher than could be achieved using standard techniques.

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

    NASA Technical Reports Server (NTRS)

    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.

  7. A CCD camera for guidance of 100-cm balloon-borne far-infrared telescope

    NASA Astrophysics Data System (ADS)

    D'Costa, S. L.; Ghosh, S. K.; Tandon, S. N.

    1991-08-01

    A charge coupled device (CCD) camera using the 488 x 380 element Fairchild CCD 222 imaging device has been developed for guidance of the 100 cm balloonborne far infrared telescope. The hardware consists of an imaging device along with its associated optics, a clock generating circuitry, the clock drivers, an 8086 microprocessor-based system, and the power supplies. The software processes the CCD image data and uses a selected star in its field of view as the guide star for pointing the telescope with an accuracy of around 4 arc s.

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

    NASA Technical Reports Server (NTRS)

    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.

  9. A cryogenically-cooled, balloon-borne far infrared survey telescope

    NASA Technical Reports Server (NTRS)

    Campbell, M. F.

    1979-01-01

    The design and performance of the Arizona cryogenically-cooled, balloon-borne, multiband far infrared survey telescope are described. The 40 cm Cassegrain telescope is completely contained in a liquid helium dewar. The focal plane array consists of Fabry optics and four detectors which each have a 12 arc minute field of view. Both photoconductive and bolometer detectors are utilized at effective wavelengths of 20, 80, 100 and 150 microns. In 1977 the telescope was used to make multicolor large scale maps of 70 square degrees in the Cygnus X region and the W3 region.

  10. Photo-induced reflectivity in the mid and far infrared

    SciTech Connect

    Haar, P.; Harrington, K.J.; Schwettman, H.A.

    1995-12-31

    Interest in switching FEL beams has motivated studies of photo-induced reflectivity in the mid and far infrared. We are particularly interested in Ge{sup 4}, GaAs, and Si{sup 5}, materials that can be pumped with a visible or near-IR conventional laser and which together cover the wavelengths from 3-100{mu}m. We have made quantitative measurements to determine the induced reflectivity, carrier lifetime, and transient absorption of these materials at several wavelengths across this range using a variety of pump laser wavelengths and pulse lengths. These measurements allow us to determine the feasibility of single pulse selection and cavity dumping with our FELs at high repetition rates.

  11. Stratospheric distribution of HCN from far infrared observations

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    Far infrared limb thermal emission measurements of the earth's stratosphere were made with a high resolution spectrometer on a balloon payload launched from Palestine, TX, on Oct. 5, 1982. Several limb sequences of a portion of the observed spectra have been analyzed for retrieval of the stratospheric HCN profile from a number of spectral lines in the 32 to 56 cm region. The mixing ratio profile in the 20 to 37 km altitude range has been retrieved with 2-sigma uncertainties of about 4-5 km. The HCN volume mixing ratio is found to be about 139 pptv at 20 km, 127 pptv at 25 km, and increasing to 172 pptv at 37 km. The results are compared with measurements by other groups and with photochemical model calculations reported in the literature.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Far infrared radiation (FIR): its biological effects and medical applications

    PubMed Central

    Vatansever, Fatma; Hamblin, Michael R.

    2013-01-01

    Far infrared (FIR) radiation (λ = 3–100 μm) is a subdivision of the electromagnetic spectrum that has been investigated for biological effects. The goal of this review is to cover the use of a further sub-division (3– 12 μm) of this waveband, that has been observed in both in vitro and in vivo studies, to stimulate cells and tissue, and is considered a promising treatment modality for certain medical conditions. Technological advances have provided new techniques for delivering FIR radiation to the human body. Specialty lamps and saunas, delivering pure FIR radiation (eliminating completely the near and mid infrared bands), have became safe, effective, and widely used sources to generate therapeutic effects. Fibers impregnated with FIR emitting ceramic nanoparticles and woven into fabrics, are being used as garments and wraps to generate FIR radiation, and attain health benefits from its effects. PMID:23833705

  15. Far-Infrared Imaging Spectroscopy with SAFIRE on SOFIA

    NASA Technical Reports Server (NTRS)

    Shafer, Richard A.; Benford, D. J.; Irwin, K. D.; Moseley, S. H.; Pajot, F.; Stacey, G. J.; Staguhn, J. G.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The SOFIA airborne observatory will provide a high spatial resolution, low background telescope for far-infrared astrophysical investigations. Selected as a PI instrument for SOFIA, SAFIRE is an imaging Fabry-Perot spectrograph covering 100 micrometers - 655 micrometers, with spectral resolving power of approx. 1500 (200 kilometers per second). This resolution is well matched to extragalactic emission lines and yields the greatest sensitivity for line detection. SAFIRE will make important scientific contributions to the study of the powering of ULIRGs and AGN, the role of CII cooling in extragalactic star formation, the evolution of matter in the early Universe, and the energetics of the Galactic center. SAFIRE will employ a two-dimensional pop-up barometer array in a 16 x 32 format to provide background-limited imaging spectrometry. Superconducting transition edge barometers and SQUID amplifiers have been developed for these detectors.

  16. Far-Infrared Imaging Spectroscopy with SAFIRE on SOFIA

    NASA Technical Reports Server (NTRS)

    Shafer, Richard A.; Benford, D. J.; Irwin, K. D.; Moseley, S. H.; Pajot, F.; Stacey, G. J.; Staguhn, J. G.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The SOFIA airborne observatory will provide a high spatial resolution, low background telescope for far-infrared astrophysical investigations. Selected as a PI instrument for SOFIA, SAFIRE is an imaging Fabry-Perot spectrograph covering 100 micrometers - 655 micrometers, with spectral resolving power of approx. 1500 (200 kilometers per second). This resolution is well matched to extragalactic emission lines and yields the greatest sensitivity for line detection. SAFIRE will make important scientific contributions to the study of the powering of ULIRGs and AGN, the role of CII cooling in extragalactic star formation, the evolution of matter in the early Universe, and the energetics of the Galactic center. SAFIRE will employ a two-dimensional pop-up barometer array in a 16 x 32 format to provide background-limited imaging spectrometry. Superconducting transition edge barometers and SQUID amplifiers have been developed for these detectors.

  17. Far infrared radiation (FIR): its biological effects and medical applications.

    PubMed

    Vatansever, Fatma; Hamblin, Michael R

    2012-11-01

    Far infrared (FIR) radiation (λ = 3-100 μm) is a subdivision of the electromagnetic spectrum that has been investigated for biological effects. The goal of this review is to cover the use of a further sub-division (3- 12 μm) of this waveband, that has been observed in both in vitro and in vivo studies, to stimulate cells and tissue, and is considered a promising treatment modality for certain medical conditions. Technological advances have provided new techniques for delivering FIR radiation to the human body. Specialty lamps and saunas, delivering pure FIR radiation (eliminating completely the near and mid infrared bands), have became safe, effective, and widely used sources to generate therapeutic effects. Fibers impregnated with FIR emitting ceramic nanoparticles and woven into fabrics, are being used as garments and wraps to generate FIR radiation, and attain health benefits from its effects.

  18. Far-Infrared Blocked Impurity Band Detector Development

    NASA Technical Reports Server (NTRS)

    Hogue, H. H.; Guptill, M. T.; Monson, J. C.; Stewart, J. W.; Huffman, J. E.; Mlynczak, M. G.; Abedin, M. N.

    2007-01-01

    DRS Sensors & Targeting Systems, supported by detector materials supplier Lawrence Semiconductor Research Laboratory, is developing far-infrared detectors jointly with NASA Langley under the Far-IR Detector Technology Advancement Partnership (FIDTAP). The detectors are intended for spectral characterization of the Earth's energy budget from space. During the first year of this effort we have designed, fabricated, and evaluated pilot Blocked Impurity Band (BIB) detectors in both silicon and germanium, utilizing pre-existing customized detector materials and photolithographic masks. A second-year effort has prepared improved silicon materials, fabricated custom photolithographic masks for detector process, and begun detector processing. We report the characterization results from the pilot detectors and other progress.

  19. A far infrared photometer for characterization of stratospheric perturbations

    NASA Astrophysics Data System (ADS)

    D'Andreta, Gerardo; D'Addio, Lorenzo; Melchiorri, Bianca

    1995-10-01

    The sensitivity of the new generation of He-3 bolometers is such that it is possible to detect tiny atmospheric perturbations occurring at high altitude by means of a submillimetric photometer: an excess of 1% along one km of the stratosphere for H2O vapour is detectable up to 10 km of altitude, while the same excess for O2 is detectable up to 20 km and up to 35 km in the case of Ozone. In the present paper we describe a multi-band photometer operating at the focal plane of MITO (Millimeter and Infrared Testagrigia Observatory), capable of discriminating atmospheric perturbations in altitude and in chemical composition. The instrument is devoted to the study of the dynamics of the upper atmosphere in a long range program of far infrared observations.

  20. Stressed photoconductive detector for far-infrared space applications.

    PubMed

    Wang, J Q; Richards, P L; Beeman, J W; Haller, E E

    1987-11-15

    An optimized leaf-spring apparatus for applying uniaxial stress to a Ge:Ga far-infrared photoconductor has been designed and tested. This design has significant advantages for space applications which require high quantum efficiency and stable operation over long periods of time. The important features include adequate spring deflection with relatively small overall size, torque-free stress, easy measurement of applied stress, and a detector configuration with high responsivity. One-dimensional arrays of stressed photoconductors can be constructed using this design. A peak responsivity of 38 A/W is achieved in a detector with a cutoff wavelength of 200 microm, which was operated at a temperature of 2.0 K and a bias voltage equal to one half of the breakdown voltage.

  1. High resolution spectroscopy in the microwave and far infrared

    NASA Technical Reports Server (NTRS)

    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.

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

    SciTech Connect

    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.

  3. SAFIRE: Far-Infrared Imaging Spectroscopy with SOFIA

    NASA Technical Reports Server (NTRS)

    Benford, Dominic; Moseley, Harvey; Chervenak, Jay; Irwin, Kent; Pajot, Francois; Shafer, Rick; Staguhn, Johannes; Stacey, Gorden; Oegerle, William (Technical Monitor)

    2002-01-01

    The SOFIA airborne observatory will provide a high spatial resolution, low background telescope for far-infrared astrophysical investigations. Selected as a PI instrument for SOFIA, SAFIRE is an imaging Fabry-Perot spectrograph covering 145 microns-655microns, with spectral resolving power of approx. 1500 (200 kilometers per second). This resolution is well matched to extragalactic emission lines and yields the greatest sensitivity for line detection. SAFIRE will make important scientific contributions to the study of the powering of ULIRGs and AGN, the role of CII cooling in extragalactic star formation, the evolution of matter in the early Universe, and the energetics of the Galactic center. SAFIRE will employ a two-dimensional pop-up bolometer array to provide background limited imaging spectrometry. Superconducting transition edge bolometers and SQUID amplifiers have been developed for these detectors.

  4. Atmospheric and Spectroscopic Research in the Far Infrared

    NASA Technical Reports Server (NTRS)

    Park, Kwangjai

    1998-01-01

    The spectroscopic measurements of molecular parameters constitute one of the major areas of our research program. This part of our program has been conducted in close collaboration with Smithsonian Astrophysical Observatory (SAO) and National Institute of Standards and Technology (NIST). The references on HO2, OH, and O2 that appear on the publication list are examples of this type of work completed during the grant period. These pressure-broadening studies have provided the kind of improvements needed in the database for retrieving atmospheric profiles from far infrared limb sensing data. One example of this linkage between the pressure broadening studies and the improvements in data retrieval is described in the paper on HBr (paper #4, publication list). The retrieval of the concentration profile of this important species from the IBEX data was facilitated by a number of performance improvement factors, not the least of which was the database improvements.

  5. Stratospheric HBr mixing ratio obtained from far infrared emission spectra

    SciTech Connect

    Park, J.H. ); Carli, B. ); Barbis, A. )

    1989-08-01

    Emission features of HBr isotopes have been identified in high-resolution far-infrared emission spectra obtained with a balloon-born Fourier transform spectrometer in the spring of 1979 at 32{degree}N latitude. When six single-scan spectra at a zenith angle of 93.2{degree} were averaged, two features of HBr isotopes at 50.054 and 50.069 cm{sup {minus}1} were obtained with a signal-to-noise ratio of 2.5. The volume mixing ratio retrieved from the average spectrum is 2.0 {times} 10{sub {minus}11}, which is assumed to be constant above 28 km, with an uncertainty of 35%. This stratospheric amount of HBr is about the same as the current level of tropospheric organic bromine compounds, 25 pptv. Thus, HBr could be the major stratospheric bromine species.

  6. Far-infrared emissivity measurements of reflective surfaces

    NASA Technical Reports Server (NTRS)

    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.

  7. Microwave, Millimeter, Submillimeter, and Far Infrared Spectral Databases

    NASA Technical Reports Server (NTRS)

    Pearson, J. C.; Pickett, H. M.; Drouin, B. J.; Chen, P.; Cohen, E. A.

    2002-01-01

    The spectrum of most known astrophysical molecules is derived from transitions between a few hundred to a few hundred thousand energy levels populated at room temperature. In the microwave and millimeter wave regions. spectroscopy is almost always performed with traditional microwave techniques. In the submillimeter and far infrared microwave technique becomes progressively more technologically challenging and infrared techniques become more widely employed as the wavelength gets shorter. Infrared techniques are typically one to two orders of magnitude less precise but they do generate all the strong features in the spectrum. With microwave technique, it is generally impossible and rarely necessary to measure every single transition of a molecular species, so careful fitting of quantum mechanical Hamiltonians to the transitions measured are required to produce the complete spectral picture of the molecule required by astronomers. The fitting process produces the most precise data possible and is required in the interpret heterodyne observations. The drawback of traditional microwave technique is that precise knowledge of the band origins of low lying excited states is rarely gained. The fitting of data interpolates well for the range of quantum numbers where there is laboratory data, but extrapolation is almost never precise. The majority of high resolution spectroscopic data is millimeter or longer in wavelength and a very limited number of molecules have ever been studied with microwave techniques at wavelengths shorter than 0.3 millimeters. The situation with infrared technique is similarly dire in the submillimeter and far infrared because the black body sources used are competing with a very significant thermal background making the signal to noise poor. Regardless of the technique used the data must be archived in a way useful for the interpretation of observations.

  8. Analysis of cirrus cloud spectral signatures in the far infrared

    NASA Astrophysics Data System (ADS)

    Maestri, T.; Rizzi, R.; Tosi, E.; Veglio, P.; Palchetti, L.; Bianchini, G.; Di Girolamo, P.; Masiello, G.; Serio, C.; Summa, D.

    2014-07-01

    This paper analyses high spectral resolution downwelling radiance measurements in the far infrared in the presence of cirrus clouds taken by the REFIR-PAD interferometer, deployed at 3500 m above the sea level at the Testa Grigia station (Italy), during the Earth COoling by WAter vapouR emission (ECOWAR) campaign. Atmospheric state and cloud geometry are characterised by the co-located millimeter-wave spectrometer GBMS and by radiosonde profile data, an interferometer (I-BEST) and a Raman lidar system deployed at a nearby location (Cervinia). Cloud optical depth and effective diameter are retrieved from REFIR-PAD data using a limited number of channels in the 820-960 cm-1 interval. The retrieved cloud parameters are the input data for simulations covering the 250-1100 cm-1 band in order to test our ability to reproduce the REFIR-PAD spectra in the presence of ice clouds. Inverse and forward simulations are based on the same radiative transfer code. A priori information concerning cloud ice vertical distribution is used to better constrain the simulation scheme and an analysis of the degree of approximation of the phase function within the radiative transfer codes is performed to define the accuracy of computations. Simulation-data residuals over the REFIR-PAD spectral interval show an excellent agreement in the window region, but values are larger than total measurement uncertainties in the far infrared. Possible causes are investigated. It is shown that the uncertainties related to the water vapour and temperature profiles are of the same order as the sensitivity to the a priori assumption on particle habits for an up-looking configuration. In case of a down-looking configuration, errors due to possible incorrect description of the water vapour profile would be drastically reduced.

  9. FAR-INFRARED IMAGING OBSERVATIONS OF THE CHAMAELEON REGION

    SciTech Connect

    Ikeda, Norio; Kitamura, Yoshimi; Takita, Satoshi; Ueno, Munetaka; Suzuki, Toyoaki

    2012-01-20

    We have carried out far-infrared imaging observations toward the Chamaeleon star-forming region by the Far-Infrared Surveyor (FIS) on board the AKARI satellite. The AKARI images cover a total area of 33.79 deg{sup 2}, corresponding to 210 pc{sup 2} at the distance to the source. Using the FIS bands of 65-160 {mu}m and the COBE/DIRBE bands of 60-240 {mu}m, we constructed column density maps of cold (11.7 K) and warm (22.1 K) dust components with a linear resolution of 0.04 pc. On the basis of their spatial distributions and physical properties, we interpret that the cold component corresponds to the molecular clouds and the warm one the cold H I clouds, which are thought to be in a transient phase between atomic and molecular media. The warm component is shown to be uniformly distributed at a large spatial scale of {approx}50 pc, while a several pc-scale gradient along the east-west direction is found in the distribution of the cold component. The former is consistent with a formation scenario of the cold H I clouds through the thermal instability in the warm neutral medium triggered by a 100 pc scale supernova explosion. This scenario, however, cannot produce the latter, several pc-scale gradient in molecular cloud mass. We conclude that the gravitational fragmentation of the cold H I cloud likely created the molecular clouds with spatial scale as small as several pc.

  10. Kinetic inductance detectors for far-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    Streyer, William Henderson

    The dissertation aims to build a case for the benefits and means of investigating novel optical materials and devices operating in the underdeveloped far-infrared (20 - 60 microns) region of the electromagnetic spectrum. This dissertation and the proposed future investigations described here have the potential to further the advancement of new and enhanced capabilities in fields such as astronomy, medicine, and the petrochemical industry. The first several completed projects demonstrate techniques for developing far-infrared emission sources using selective thermal emitters, which could operate more efficiently than their simple blackbody counterparts commonly used as sources in this wavelength region. The later projects probe the possible means of linking bulk optical phonon populations through interaction with surface modes to free space photons. This is a breakthrough that would enable the development of a new class of light sources operating in the far-infrared. Chapter 1 introduces the far-infrared wavelength range along with many of its current and potential applications. The limited capabilities of the available optical architecture in this range are outlined along with a discussion of the state-of-the-art technology available in this range. Some of the basic physical concepts routinely applied in this dissertation are reviewed; namely, the Drude formalism, semiconductor Reststrahlen bands, and surface polaritons. Lastly, some of the physical challenges that impede the further advancement of far-infrared technology, despite remarkable recent success in adjacent regions of the electromagnetic spectrum, are discussed. Chapter 2 describes the experimental and computational methods employed in this dissertation. Spectroscopic techniques used to investigate both the mid-infrared and far-infrared wavelength ranges are reviewed, including a brief description of the primary instrument of infrared spectroscopy, the Fourier Transform Infrared (FTIR) spectrometer

  12. DARK-FIELD ILLUMINATION SYSTEM

    DOEpatents

    Norgren, D.U.

    1962-07-24

    A means was developed for viewing objects against a dark background from a viewing point close to the light which illuminates the objects and under conditions where the back scattering of light by the objects is minimal. A broad light retro-directing member on the opposite side of the objects from the light returns direct light back towards the source while directing other light away from the viewing point. The viewing point is offset from the light and thus receives only light which is forwardly scattered by an object while returning towards the source. The object is seen, at its true location, against a dark background. The invention is particularly adapted for illuminating and viewing nuclear particle tracks in a liquid hydrogen bubble chamber through a single chamber window. (AEC)

  13. Effect of the Dosage of Tourmaline on Far Infrared Emission Properties of Tourmaline/Glass Composite Materials.

    PubMed

    Zhang, Hongchen; Meng, Junping; Liang, Jinsheng; Liu, Jie; Zeng, Zhaoyang

    2016-04-01

    Tourmaline/glass composite materials were prepared by sintering at 600 °C using micron-size tourmaline mineral and glass powders as raw materials. The glass has lower melting point than the transition temperature of tourmaline. The Fourier transform infrared spectroscopy showed that the far infrared emissivity of composite was significantly higher than that of either tourmaline or glass powders. A highest far infrared emissivity of 0.925 was obtained when the dosage of tourmaline was 10 wt%. The effects of the amount of tourmaline on the far infrared emission properties of composite was also systematically studied by field emission scanning electron microscope and X-ray diffraction. The tourmaline phase was observed in the composite, showing a particle size of about 70 nm. This meant that the tourmaline particles showed nanocrystallization. They distributed homogenous in the glass matrix when the dosage of tourmaline was not more than 20 wt%. Two reasons were attributed to the improved far infrared emission properties of composite: the particle size of tourmaline-doped was nanocrystallized and the oxidation of Fe2+ (0.076 nm in radius) to Fe3+ (0.064 nm in radius) took place inside the tourmaline-doped. This resulted in the shrinkage of unit cell of the tourmaline in the composite.

  14. Herschel-ATLAS: the far-infrared-radio correlation at z < 0.5

    NASA Astrophysics Data System (ADS)

    Jarvis, Matt J.; Smith, D. J. B.; Bonfield, D. G.; Hardcastle, M. J.; Falder, J. T.; Stevens, J. A.; Ivison, R. J.; Auld, R.; Baes, M.; Baldry, I. K.; Bamford, S. P.; Bourne, N.; Buttiglione, S.; Cava, A.; Cooray, A.; Dariush, A.; de Zotti, G.; Dunlop, J. S.; Dunne, L.; Dye, S.; Eales, S.; Fritz, J.; Hill, D. T.; Hopwood, R.; Hughes, D. H.; Ibar, E.; Jones, D. H.; Kelvin, L.; Lawrence, A.; Leeuw, L.; Loveday, J.; Maddox, S. J.; Michałowski, M. J.; Negrello, M.; Norberg, P.; Pohlen, M.; Prescott, M.; Rigby, E. E.; Robotham, A.; Rodighiero, G.; Scott, D.; Sharp, R.; Temi, P.; Thompson, M. A.; van der Werf, P.; van Kampen, E.; Vlahakis, C.; White, G.

    2010-11-01

    We use data from the Herschel-ATLAS to investigate the evolution of the far-infrared-radio correlation over the redshift range 0 < z < 0.5. Using the total far-infrared luminosity of all >5σ sources in the Herschel-ATLAS Science Demonstration Field and cross-matching these data with radio data from the Faint Images of the Radio Sky at Twenty-Centimetres (FIRST) survey and the NRAO Very Large Array (VLA) Northern Sky Survey (NVSS), we obtain 104 radio counterparts to the Herschel sources. With these data we find no evidence for evolution in the far-infrared-radio correlation over the redshift range 0 < z < 0.5, where the median value for the ratio between far-infrared and radio luminosity, qIR, over this range is qIR = 2.40 +/- 0.12 (and a mean of qIR = 2.52 +/- 0.03 accounting for the lower limits), consistent with both the local value determined from IRAS and values derived from surveys targeting the high-redshift Universe. By comparing the radio fluxes of our sample measured from both FIRST and NVSS we show that previous results suggesting an increase in the value of qIR from high to low redshift may be the result of resolving out extended emission of the low-redshift sources with relatively high-resolution interferometric data, although contamination from active galactic nuclei could still play a significant role. We also find tentative evidence that the longer wavelength cooler dust is heated by an evolved stellar population which does not trace the star formation rate as closely as the shorter wavelength <~ 250μm emission or the radio emission, supporting suggestions based on detailed models of individual galaxies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. E-mail: m.j.jarvis@herts.ac.uk

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

    NASA Astrophysics Data System (ADS)

    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.

  16. The Galactic Center in the Far-infrared

    NASA Astrophysics Data System (ADS)

    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.

  17. The Far-Infrared Spectrum of Arp 220

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    ISO/LWS grating observations of the ultraluminous infrared galaxy Arp 220 shows absorption in molecular lines of OH, H 2 0 , CH, NH, and "3, well as in the [0 I] 63 pm line and emission in the [C 111 158 pm 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 pm 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 (about 2 x 10 sup 17 cm sup-2). The H2O column density is also high toward the nucleus (2 - 10 x 1017 cm-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 NH3 toward the nucleus, with values of about 1.5 x 10supl6 cmsup-2 and about 3 x 10supl6 cmsup-2, respectively, whereas the NH2 column density is lower than about 2 x 10sup15 cmsup-2. A combination of PDRs in the extended region and hot cores with enhanced H20 photodissociation and a possible shock contribution in the nuclei may explain the relative column densities of OH and H20, whereas the nitrogen chemistry may be strongly affected by cosmic ray ionization. The [C II] 158 pm line is well reproduced by our models and its "deficit" relative to the CII/FIR ratio in normal and starburst galaxies is suggested to be mainly a consequence of the dominant non-PDR component of far- infrared radiation, ALTHOUGH OUR MODELS ALONE CANNOT RULE OUT EXTINCTION EFFECTS IN THE

  18. Far-Infrared Investigation of Class 0 Sources: Line Cooling

    NASA Astrophysics Data System (ADS)

    Giannini, Teresa; Nisini, Brunella; Lorenzetti, Dario

    2001-07-01

    We have investigated with the Long Wavelength Spectrometer (LWS) of the Infrared Space Observatory (ISO) the far-infrared spectra (43-197 μm) of a sample of 17 class 0 sources and their associated outflows. In addition to [O I] 63 μm, the pure rotational lines of abundant molecules such as CO, H2O, and OH are frequently observed in these sources, at variance with more evolved young stellar objects. We found, in agreement with previous studies conducted on individual sources, that the molecular line excitation arises from small regions, with typical sizes of 10-9 sr, of warm (200far-infrared (FIR) line cooling LFIR=L(O I)+L(CO)+L(H2O)+L(OH), which amounts to ~10-2 to 10-1 Lsolar, is roughly equal to the outflow kinetic luminosity as estimated by means of millimeter molecular mapping. This circumstance demonstrates that the FIR line cooling can be a valid direct measure of the power deposited in the outflow, not affected by geometrical or opacity problems like the determination of Lkin or by extinction problems like the near-infrared shocked H2 emission. We finally remark that the strong molecular emission observed, and in particular H2O emission, is a peculiarity of the environments of class 0 sources. The present analysis shows that the ratio between FIR molecular line luminosity and bolometric luminosity (Lmol/Lbol) is always larger than ~10-3 in class 0 objects. We

  19. The Far-Infrared Spectrum of Arp 220

    NASA Technical Reports Server (NTRS)

    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

  20. The Far-Infrared Spectrum of Arp 220

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    ISO/LWS grating observations of the ultraluminous infrared galaxy Arp 220 shows absorption in molecular lines of OH, H 2 0 , CH, NH, and "3, well as in the [0 I] 63 pm line and emission in the [C 111 158 pm 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 pm 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 (about 2 x 10 sup 17 cm sup-2). The H2O column density is also high toward the nucleus (2 - 10 x 1017 cm-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 NH3 toward the nucleus, with values of about 1.5 x 10supl6 cmsup-2 and about 3 x 10supl6 cmsup-2, respectively, whereas the NH2 column density is lower than about 2 x 10sup15 cmsup-2. A combination of PDRs in the extended region and hot cores with enhanced H20 photodissociation and a possible shock contribution in the nuclei may explain the relative column densities of OH and H20, whereas the nitrogen chemistry may be strongly affected by cosmic ray ionization. The [C II] 158 pm line is well reproduced by our models and its "deficit" relative to the CII/FIR ratio in normal and starburst galaxies is suggested to be mainly a consequence of the dominant non-PDR component of far- infrared radiation, ALTHOUGH OUR MODELS ALONE CANNOT RULE OUT EXTINCTION EFFECTS IN THE

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

    SciTech Connect

    Zako, A.; Miyauchi, Y.; Koga, A.

    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.

  2. Design of a far-infrared CHI wiggler free-electron laser

    SciTech Connect

    Jackson, R.H.; Blank, M.; Freund, H.P.

    1995-12-31

    The preliminary design of a far-infrared free-electron laser with a Coaxial Hybrid Iron (CHI) wiggler is presented. The CHI wiggler consists of a central rod and outer ring of alternating ferrite and dielectric spacers. A periodic wiggler field is produced when the CHI structure is immersed in an axial magnetic field. The design under investigation makes use of 1A, 1MV annular electron beam interacting with the TE{sub 01} coaxial waveguide mode at approximately 1 THz ({lambda} = 300 {mu}m). The nominal wiggler period is 0.5 cm and the inner and outer waveguide radii are 0.4 and 0.8 cm, respectively. An axial guide field of 5-10 kG is used. The device performance is modeled with slow-time-scale nonlinear code. Self fields and axial velocity spread are included in the model. Theoretical results will be presented.

  3. SEASONAL DISAPPEARANCE OF FAR-INFRARED HAZE IN TITAN'S STRATOSPHERE

    SciTech Connect

    Jennings, Donald E.; Anderson, C. M.; Flasar, F. M.; Cottini, V.; Samuelson, R. E.; Nixon, C. A.; Kunde, V. G.; Achterberg, R. K.; De Kok, R.; Coustenis, A.; Vinatier, S.; Calcutt, S. B.

    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.

  4. Seasonal Disappearance of Far-Infrared Haze in Titan's Stratosphere

    NASA Technical Reports Server (NTRS)

    Jennings, Donald E.; Anderson, C. M.; Flasar, F. M.; Nixon, C. A.; Kunde, V. G.; Achterberg, R. K.; Cottini, V.; deKok, R.; Coustenis, A.; Vinatier, S.; hide

    2012-01-01

    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 HC3N gas in Titan's polar stratosphere, pointing to a nitrile origin.

  5. Far-Infrared Spectroscopy of Anti-Vinyl Alcohol

    NASA Astrophysics Data System (ADS)

    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)

  6. The Far-Infrared Spectral Energy Distributions of Quasars

    NASA Technical Reports Server (NTRS)

    Wilkes, Belinda J.; West, Donald K. (Technical Monitor)

    2001-01-01

    The origin of the infrared emission in Active Galactic Nuclei (AGN), whose strength is comparable to the optical/ultraviolet (OUV) emission, is generally thought to be a combination of thermal emission from dust and non-thermal, synchrotron emission. Although data are sparse, particularly in the far-infrared, the broad wavelength range of this emission suggests a wide range of temperatures and a combination of AGN and starburst heating mechanisms. The strength of the non-thermal emission is expected to be related to the radio emission. While this scenario is well-established, basic questions, such as the spatial and temperature distribution of the dust, the relative importance of AGN and starburst heating, and the significance of the non-thermal contribution remain largely undetermined. The wide wavelength range of the Infrared Space Observatory (ISO) combined with its arcmin spatial resolution and increased sensitivity facilitated the observation of a larger subset of the AGN population than previously covered, allowing these questions to be investigated in more detail. This paper will review the spectral energy distributions (SED) of AGN with particular emphasis on the infrared emission and on ISO's contributions to our knowledge. Preliminary results from ISO observations of X-ray selected and high-redshift AGN will be described.

  7. Operation results of the KSTAR far infrared interferometer

    NASA Astrophysics Data System (ADS)

    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.

  8. Far-infrared continuum absorption of olivine at low temperatures

    NASA Astrophysics Data System (ADS)

    Mutschke, H.; Zeidler, S.; Chihara, H.

    2013-10-01

    The far-infrared continuum opacity of cold dust is an important quantity for the study of debris disks in planetary systems and of protoplanetary disks. Olivine is considered the most abundant crystalline dust species in such environments. We present spectroscopic absorption measurements on olivine plates of the order of a millimeter thickness at wavelengths between 60 and 400 μ m for temperatures down to 10 K. Our data reveal a strong temperature dependence of the continuum absorption coefficient, i.e. more than an order of magnitude decrease at 100 μ m for 10 K compared to room temperature. The absolute values are generally much lower than those measured with olivine powders embedded into polyethylene pellets, even if the difference between plate and powder samples is taken into account by theoretical models. In contrast to this, the room temperature data are in relatively good agreement with simulations using optical constants determined from reflection measurements. At low temperatures, the absorption coefficient of olivine was measurable with sufficient accuracy only up to 90 μ m for 10 K and up to 110 μ m for 100 K. These data reveal a drastic change in the spectral slope (from β ~ 2.0 to β > 5.0) for the continuum underlying the 69-μ m band, which is not predicted by the low-temperature optical constants determined for forsterite.

  9. Development of the Far-Infrared Interferometric Telescope Experiment

    NASA Astrophysics Data System (ADS)

    Kanoh, T.; Shibai, H.; Fukagawa, M.; Matsuo, T.; Kato, E.; Itoh, Y.; Kawada, M.; Watabe, T.; Kohyama, T.; Matsumoto, Y.; Morishita, H.; Yamamoto, K.; Kanoh, R.; Nakashima, A.; Tanabe, M.; Narita, M.

    2009-08-01

    We have developed the Far-Infrared Interferometric Telescope Experiment (FITE). It will be the first astronomical infrared interferometer working in space. FITE is a balloon-borne telescope, and will operate in the stratosphere (at an altitude of 35 kilometers). FITE is a Michelson-type stellar interferometer, and has a long baseline of 20 meters (at maximum). The purpose of the FITE project is to achieve a high spatial resolution of 1 arcsecond at a wavelength of 100 micrometers. For its first flight, FITE has an 8-meter baseline, and the aim is to measure the interference fringes with a spatial resolution of 2.5 arcseconds. In order to achieve this aim, the two beams must be focused within 2.5 arcseconds accuracy in the imaging quality, within 10 arcseconds of accuracy in the beam alignment, and within 30 micrometers accuracy in the optical path length between the two beams. Also, the orientation of the telescope must be controlled within 2.5 arcseconds accuracy. To achieve such accuracy, the structural parts of the telescope are made of carbon-fiber reinforced plastics that have very low thermal expansion coefficient and a large Young's modulus. During observation, the optical alignment is actively adjusted by the alignment mechanisms. We also adopt a three-axis attitude control system to stabilize the orientation of the telescope with high accuracy. FITE is a very unique approach, and it serves as a step in the further development of larger-scale infrared interferometry in space.

  10. Far Infrared and Submillimeter Observations of the Giant Planets

    NASA Technical Reports Server (NTRS)

    Loewenstein, R. F.; Harper, D. A.; Hildebrand, R. H.; Keene, J.; Orton, G. S.; Whitcomb, S. E.

    1984-01-01

    Far infrared measurements of the effective temperatures of Jupiter, Saturn, Uranus and Neptune were made. The measurements presented here cover the range from 35-1000 micrometers in relatively narrow bands. The observations at lambda 350 micrometers were made at the 3m NASA Infrared Telescope Facility (IRTF) of the Mauna Kea Observatory; those at lambda 350 micrometer were made on the Kuiper Airborne Observatory (KAO). All observations of Saturn were made when the ring inclination to Earth was 1.7 deg assuring an unambiguous measurement of the flux from the disk itself. Mars was used as the calibration reference. The results represent a consistent set of calibration standards. In these measurements, it is assumed that sub b(lambda = 350 micrometers) = T sub (lambda 350 micrometers). Measurements have been made of roughly 50% of the total flux emitted by Jupiter, 65% by Saturn, and 92% by Uranus and Neptune. These measurements therefore permit a considerable reduction in the uncertainties associated with the bolometric thermal outputs of the planets. The effective temperatures (T sub e) and the ratios of emitted to absorbed solar radiation were calculated.

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

    NASA Astrophysics Data System (ADS)

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

    1998-03-01

    Composite samples of small (dimension < 10 =B5m) alkali halide crystallites in a polymer matrix (low density polyethylene and polytetrafluoroethylene) have been prepared. The far infrared optical spectra of these samples are presented, spanning a temperature range of 300 to <10 K, and a dominant absorption feature due to absorption by the transverse optic phonon of the alkali halide constituent is observed. An effective medium analysis of the samples, using the Maxwell-Garnett model, is shown to accurately reproduce the main absorption feature, but requires a shape factor for the inclusion geometry corresponding to flat, plate-like inclusions, and a plausible explanation for such a geometry is proposed. The temperature dependence of the frequency and linewidth of the absorption peak is presented. The temperature shift of the line-center-frequency is found to be adequately described by a quasiharmonic description of the transverse optic phonon energy shift of the alkali halide due to lattice 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.

  12. SAFIRE: A Far-Infrared Imaging Spectrometer for SOFIA

    NASA Technical Reports Server (NTRS)

    Shafer, Richard A.; Benford, D. J.; Moseley, S. H.; Pajot, F.; Stacey, G. J.; Staguhn, J. G.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The SOFIA airborne observatory will provide a high spatial resolution, low background telescope for far-infrared astrophysical investigations. Selected as a PI instrument for SOFIA, SAFIRE is an imaging Fabry-Perot spectrograph covering 145 micrometers-655 micrometers with spectral resolving power of approx. 1500 (200km/s). This resolution is well matched to extragalactic emission lines and yields the greatest sensitivity for line detection. SAFIRE will make important scientific contributions to the study of the powering of ULIRGs and AGN, the role of CII cooling in extragalactic star formation, the evolution of matter in the early Universe, and the energetics of the Galactic center. SAFIRE will employ a two-dimensional pop-up bolometer array to provide background-limited imaging spectrometry. Superconducting transition edge bolometers and SQUID amplifiers have been developed for these detectors. An engineering prototype of SAFIRE with a small but cutting edge detector array will be available for use during the initial SOFIA operations; further expansion to larger format arrays will be incorporated during SAFIRE's lifetime.

  13. Far-infrared Hall Effect in YBCO films

    NASA Astrophysics Data System (ADS)

    Grayson, M.; Rigal, L.; Cerne, J.; Schmadel, D. C.; Drew, H. D.; Kung, P.-J.

    2001-03-01

    In order to gain insight into the so-called "anomalous Hall effect" in Hi Tc superconductors(T.R. Chien, D.A. Brawner, Z.Z. Wang, and N.P. Ong, PRB 43, 6242(1991).) we explore Hall measurements at far-infrared (FIR) frequencies and study the temperature dependence. We separately measure the real and imaginary parts of the magneto-optical response of YBCO thin films to polarized FIR light (15-250 cm-1). The induced rotation of linearly polarized light tells us the real part of the Faraday angle, Re[θ_F(ω)], and the induced dichroism of circularly polarized light tells us Im[θ_F(ω)]. We can then deduce the complex Hall angle without resorting to Kramers-Kronig (K-K) analysis. Since both the Hall angle and the Faraday angle obey sum rules, we can compare to higher frequencies(Cerne, et al., invited talk) and determine additional information about the spectral response at intermediate frequencies. The consistency of these results is verified with K-K analysis.

  14. SAFIRE: A Far-Infrared Imaging Spectrometer for SOFIA

    NASA Technical Reports Server (NTRS)

    Shafer, Richard A.; Benford, D. J.; Moseley, S. H.; Pajot, F.; Stacey, G. J.; Staguhn, J. G.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The SOFIA airborne observatory will provide a high spatial resolution, low background telescope for far-infrared astrophysical investigations. Selected as a PI instrument for SOFIA, SAFIRE is an imaging Fabry-Perot spectrograph covering 145 micrometers-655 micrometers with spectral resolving power of approx. 1500 (200km/s). This resolution is well matched to extragalactic emission lines and yields the greatest sensitivity for line detection. SAFIRE will make important scientific contributions to the study of the powering of ULIRGs and AGN, the role of CII cooling in extragalactic star formation, the evolution of matter in the early Universe, and the energetics of the Galactic center. SAFIRE will employ a two-dimensional pop-up bolometer array to provide background-limited imaging spectrometry. Superconducting transition edge bolometers and SQUID amplifiers have been developed for these detectors. An engineering prototype of SAFIRE with a small but cutting edge detector array will be available for use during the initial SOFIA operations; further expansion to larger format arrays will be incorporated during SAFIRE's lifetime.

  15. Far-infrared mapping of Cassiopeia A with ISOPHOT

    NASA Astrophysics Data System (ADS)

    Tuffs, Richard. J.; Popescu, Cristina C.; Völk, Heinrich J.

    2005-01-01

    We investigate the content of circumstellar and ejected dust within the prototype remnant of the core collapse supernova Cassiopeia A. We used maps of the spatial and spectral distribution of far-infrared continuum emission at 60, 100, 170 and 200 μm, obtained with the ISOPHOT instrument on board the Infrared Space Observatory. Our multi-wavelength coverage, combined with the fact that the colour temperature of the emission from cold dust in Cas A differs from that of the confusing foreground clouds, allows us to achieve the first detection of thermal FIR emission from the remnant longwards of 100 μm. We find no evidence for the presence of 2-4 Msolar of cold dust in the remnant as reported by Dunne et al. (2004) on the basis of SCUBA maps. In addition to the cold dust, we detect small quantities of hot, collisionally-heated grains towards both the shocked X-ray-emitting ejecta and circumstellar medium, as previously detected in measurements by IRAS.

  16. Far infrared microbolometers for radiometric measurements of ice cloud

    NASA Astrophysics Data System (ADS)

    Ngo Phong, Linh; Proulx, Christian; Oulachgar, Hassane; Châteauneuf, François

    2015-02-01

    Focal planes of 80x60 VOx microbolometers with pixel pitch of 104 μm were developed in support of the remote sensing of ice clouds in the spectral range from 7.9 to 50 μm. A new design that relies on the use of central posts to support the microbolometer platform was shown effective in minimizing the structural deformation usually occurred in platforms of large area. A process for goldblack coating and patterning of the focal plane arrays was established. It was found that the goldblack absorbs more than 98 % and 92 % of incident light respectively at wavelengths shorter and longer than 20 μm. Moreover, a spectral uniformity of better than 96 % was achieved in all spectral channels required for the measurements. The noise figures derived from the data acquired over short periods of acquisition time showed the evidence of a correlation with the format of the addressed sub-arrays. This correlation was not observed in the data acquired over long periods of time, suggesting the presence of low frequency effects. Regardless of the length of acquisition time, an improvement of noise level could be confirmed when the operating temperature was increased. The dependence of responsivity on sub-array format and operating temperature was investigated. The noise equivalent power derived from this study was found to be in the range from 45 to 80 pW, showing that the far infrared focal plane arrays are suited for use in the intended application.

  17. Development of a Submillimeter/Far-Infrared Radiometer for Cirrus Measurements

    NASA Technical Reports Server (NTRS)

    Hayton, Darren; Ade, Peter; Evans, Frank; Lee, Clare; Nolt, Ira; Vanek, Mike

    2004-01-01

    We introduce a low-cost, lightweight and compact polarisation-sensitive radiometer for the measurement of Cirrus clouds in the submillimeter and far-infrared region (10 150 cm-1). It is widely recognised that enhanced global measurements of cirrus properties are essential to the development of General Circulation and Climate Prediction Models since cirrus clouds have a strong effect on the Earth's Global Radiation Budget. The purpose of this project is to design and build a novel instrument suitable for aircraft deployment in order to measure Ice Water Path (IWP) along with cirrus particle size and shape. This airborne instrument, which is currently under development in Cardiff, will serve as a prototype for a future satellite-based radiometer. The radiometer will capitalize on the ongoing measurements of the NASA-led, Fourier Transform interferometer-based, FIRSC (Far-Infrared Sensor for Cirrus) instrument for which Cardiff has been closely associated. Data from FIRSC campaigns is being used to select optimum radiometer channels that exhibit good sensitivity to specific cirrus. This new multichannel radiometer will, however, have some key advantages over similar spectroscopic instruments, for example, portability, increased optical efficiency, a multi-angle field of view and a reduced integration period leading to an improved spatial resolution. The radiometer will benefit from the application of state-of-the-art submm/FIR polarizer and solid filter technology currently being developed in Cardiff. The instrument will require a detector array that is robust enough to withstand aircraft/space deployment.

  18. A single-photon detector in the far-infrared range

    PubMed

    Komiyama; Astafiev; Antonov; Kutsuwa; Hirai

    2000-01-27

    The far-infrared region (wavelengths in the range 10 microm-1 mm) is one of the richest areas of spectroscopic research, encompassing the rotational spectra of molecules and vibrational spectra of solids, liquids and gases. But studies in this spectral region are hampered by the absence of sensitive detectors--despite recent efforts to improve superconducting bolometers, attainable sensitivities are currently far below the level of single-photon detection. This is in marked contrast to the visible and near-infrared regions (wavelengths shorter than about 1.5 microm), in which single-photon counting is possible using photomultiplier tubes. Here we report the detection of single far-infrared photons in the wavelength range 175-210 microm (6.0-7.1 meV), using a single-electron transistor consisting of a semiconductor quantum dot in high magnetic field. We detect, with a time resolution of a millisecond, an incident flux of 0.1 photons per second on an effective detector area of 0.1 mm2--a sensitivity that exceeds previously reported values by a factor of more than 10(4). The sensitivity is a consequence of the unconventional detection mechanism, in which one absorbed photon leads to a current of 10(6)-10(12) electrons through the quantum dot. By contrast, mechanisms of conventional detectors or photon assisted tunnelling in single-electron transistors produce only a few electrons per incident photon.

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

    NASA Astrophysics Data System (ADS)

    Hardcastle, M. J.; Virdee, J. S.; 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.; Michałowski, 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.

    2010-11-01

    We use the Herschel-Astrophysical Terahertz Large Area Survey (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 active galactic nuclei (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-dependent effect that is not seen in our data (which only span a limited range in radio luminosity) but which may well be detectable with the full Herschel-ATLAS data set. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. E-mail: m.j.hardcastle@herts.ac.uk

  20. The radio emission from the ultraluminous far-infrared galaxy NGC 6240

    NASA Technical Reports Server (NTRS)

    Colbert, Edward J. M.; Wilson, Andrew S.; Bland-Hawthorn, Jonathan

    1994-01-01

    We present new radio observations of the 'prototypical' ultraluminous far-infrared galaxy NGC 6240, obtained using the Very Large Array (VLA) at lambda = 20 cm in B-configuration and at lambda = 3.6 cm in A-configuration. These data, along with those from four previous VLA observations, are used to perform a comprehensive study of the radio emission from NGC 6240. Approximately 70% (approximately 3 x 10(exp 23) W/Hz) of the total radio power at 20 cm originates from the nuclear region (approximately less than 1.5 kpc), of which half is emitted by two unresolved (R approximately less than 36 pc) cores and half by a diffuse component. The radio spectrum of the nuclear emission is relatively flat (alpha approximately equals 0.6; S(sub nu) proportional to nu(exp -alpha). The supernova rate required to power the diffuse component is consistent with that predicted by the stellar evolution models of Rieke et al. (1985). If the radio emission from the two compact cores is powered by supernova remnants, then either the remnants overlap and form hot bubbles in the cores, or they are very young (approximately less than 100 yr.) Nearly all of the remaining 30% of the total radio power comes from an 'armlike' region extending westward from the nuclear region. The western arm emission has a steep spectrum (alpha approximately equals 1.0), suggestive of aging effects from synchrotron or inverse-Compton losses, and is not correlated with starlight; we suggest that it is synchrotron emission from a shell of material driven by a galactic superwind. Inverse Compton scattering of far-infrared photons in the radio sources is expected to produce an X-ray flux of approximately 2 - 6 x 10(exp -14) ergs/s/sq cm in the 2 - 10 keV band. No significant radio emission is detected from or near the possible ultramassive 'dark core'.

  1. The radio emission from the ultraluminous far-infrared galaxy NGC 6240

    NASA Technical Reports Server (NTRS)

    Colbert, Edward J. M.; Wilson, Andrew S.; Bland-Hawthorn, Jonathan

    1994-01-01

    We present new radio observations of the 'prototypical' ultraluminous far-infrared galaxy NGC 6240, obtained using the Very Large Array (VLA) at lambda = 20 cm in B-configuration and at lambda = 3.6 cm in A-configuration. These data, along with those from four previous VLA observations, are used to perform a comprehensive study of the radio emission from NGC 6240. Approximately 70% (approximately 3 x 10(exp 23) W/Hz) of the total radio power at 20 cm originates from the nuclear region (approximately less than 1.5 kpc), of which half is emitted by two unresolved (R approximately less than 36 pc) cores and half by a diffuse component. The radio spectrum of the nuclear emission is relatively flat (alpha approximately equals 0.6; S(sub nu) proportional to nu(exp -alpha). The supernova rate required to power the diffuse component is consistent with that predicted by the stellar evolution models of Rieke et al. (1985). If the radio emission from the two compact cores is powered by supernova remnants, then either the remnants overlap and form hot bubbles in the cores, or they are very young (approximately less than 100 yr.) Nearly all of the remaining 30% of the total radio power comes from an 'armlike' region extending westward from the nuclear region. The western arm emission has a steep spectrum (alpha approximately equals 1.0), suggestive of aging effects from synchrotron or inverse-Compton losses, and is not correlated with starlight; we suggest that it is synchrotron emission from a shell of material driven by a galactic superwind. Inverse Compton scattering of far-infrared photons in the radio sources is expected to produce an X-ray flux of approximately 2 - 6 x 10(exp -14) ergs/s/sq cm in the 2 - 10 keV band. No significant radio emission is detected from or near the possible ultramassive 'dark core'.

  2. Far-infrared excess emission as a tracer of disk-halo interaction

    NASA Astrophysics Data System (ADS)

    Lenz, D.; Kerp, J.; Flöer, L.; Winkel, B.; Boulanger, F.; Lagache, G.

    2015-01-01

    Context. Given the current and past star-formation in the Milky Way in combination with the limited gas supply, the re-fuelling of the reservoir of cool gas is an important aspect of Galactic astrophysics. The infall of H i halo clouds can, among other mechanisms, contribute to solving this problem. Aims: We study the intermediate-velocity cloud IVC135+54 and its spatially associated high-velocity counterpart to look for signs of a past or ongoing interaction. Methods: Using the Effelsberg-Bonn H i Survey data, we investigated the interplay of gas at different velocities. In combination with far-infrared Planck and IRIS data, we extended this study to interstellar dust and used the correlation of the data sets to infer information on the dark gas. Results: The velocity structure indicates a strong compression and deceleration of the infalling high-velocity cloud (HVC), associated with far-infrared excess emission in the intermediate-velocity cloud. This excess emission traces molecular hydrogen, confirming that IVC135+54 is one of the very few molecular halo clouds. The high dust emissivity of IVC135+54 with respect to the local gas implies that it consists of disk material and does not, unlike the HVC, have an extragalactic origin. Conclusions: Based on the velocity structure of the HVC and the dust content of the IVC, a physical connection between them appears to be the logical conclusion. Since this is not compatible with the distance difference between the two objects, we conclude that this particular HVC might be much closer to us than complex C. Alternatively, the indicators for an interaction are misleading and have another origin.

  3. The properties of mid- to far- infrared emission in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Sakon, Itsuki; Onaka, Takashi; Kaneda, Hidehiro; Tokura, Daisuke; Tajiri, Yuka Y.; Takahashi, Hidenori; Kato, Daisuke; Onishi, Toshikazu

    similar to the Milky way, suggesting the lack of the smaller VSGs (see Figure 2). Next we examine the IRAS colors in the LMC and find that the "linearly rising component" in the plots of excess emission relative to the total far-infrared emission against the dust temperature seen in our Galactic plane (Sakon et al. 2004) also exists in the LMC data and corresponds to the data around young stellar clusters. At the same time, we recognize that the "horizontally spreading component" in the same plots corresponds to the data in general regions of the LMC other than those around young star clusters. These bimodal sequences can be explained by the temperature range of dust which we see at once in the line of sight; the range of dust temperature we see at once is greatly affected whether young star clusters are included or not. We have also investigated the properties of PAHs and VSGs in CO molecular clouds, in which we find that the color of 12μm to 25μm is typically large. This characteristic may be attributed to the shielding of UV radiation fields in dense molecular clouds.

  4. AKARI far-infrared maps of the zodiacal dust bands

    NASA Astrophysics Data System (ADS)

    Ootsubo, Takafumi; Doi, Yasuo; Takita, Satoshi; Nakagawa, Takao; Kawada, Mitsunobu; Kitamura, Yoshimi; Matsuura, Shuji; Usui, Fumihiko; Arimatsu, Ko

    2016-06-01

    Zodiacal emission is thermal emission from interplanetary dust. Its contribution to the sky brightness is non-negligible in the region near the ecliptic plane, even in the far-infrared (far-IR) wavelength regime. We analyze zodiacal emission observed by the AKARI far-IR all-sky survey, which covers 97% of the entire sky at arcminute-scale resolution in four photometric bands, with central wavelengths of 65, 90, 140, and 160 μm. AKARI detected small-scale structures in the zodiacal dust cloud, including the asteroidal dust bands and the circumsolar ring, at far-IR wavelengths. Although the smooth component of the zodiacal emission structure in the far-IR sky can be reproduced well by models based on existing far-IR observations, previous zodiacal emission models have discrepancies in the small-scale structures compared with observations. We investigate the geometry of the small-scale dust-band structures in the AKARI far-IR all-sky maps and construct template maps of the asteroidal dust bands and the circumsolar ring components based on the AKARI far-IR maps. In the maps, ± 1.4°, ± 2.1°, and ± 10° asteroidal dust-band structures are detected in the 65 μm and 90 μm bands. A possible ± 17° band may also have been detected. No evident dust-band structures are identified in either the 140 μm or the 160 μm bands. By subtracting the dust-band templates constructed in this paper, we can achieve a similar level of flux calibration of the AKARI far-IR all-sky maps in the |β| < 40° region to that in the region for |β| > 40°.

  5. The Intrinsic Far-infrared Continua of Type-1 Quasars

    NASA Astrophysics Data System (ADS)

    Lyu, Jianwei; Rieke, George H.

    2017-06-01

    The range of currently proposed active galactic nucleus (AGN) far-infrared templates results in uncertainties in retrieving host galaxy information from infrared observations and also undermines constraints on the outer part of the AGN torus. We discuss how to test and reconcile these templates. Physically, the fraction of the intrinsic AGN IR-processed luminosity compared with that from the central engine should be consistent with the dust-covering factor. In addition, besides reproducing the composite spectral energy distributions (SEDs) of quasars, a correct AGN IR template combined with an accurate library of star-forming galaxy templates should be able to reproduce the IR properties of the host galaxies, such as the luminosity-dependent SED shapes and aromatic feature strengths. We develop tests based on these expected behaviors and find that the shape of the AGN intrinsic far-IR emission drops off rapidly starting at ˜20 μm and can be matched by an Elvis et al.-like template with a minor modification. Despite the variations in the near- to mid-IR bands, AGNs in quasars and Seyfert galaxies have remarkably similar intrinsic far-IR SEDs at λ ˜ 20-100 μm, suggesting a similar emission character of the outermost region of the circumnuclear torus. The variations of the intrinsic AGN IR SEDs among the type-1 quasar population can be explained by the changing relative strengths of four major dust components with similar characteristic temperatures, and there is evidence for compact AGN-heated dusty structures at sub-kiloparsec scales in the far-IR.

  6. Far-infrared spectroscopy of impurities in semiconductors

    NASA Astrophysics Data System (ADS)

    Stradling, R. A.

    1991-06-01

    Far-infrared spectroscopy of the electronic transitions between bound states of impurities provides a very high resolution technique for studying chemical shifts and thereby identifying residual contaminants. The use of photoconductivity generated within the sample itself, usually by the photothermal mechanism ("photothermal ionisation spectroscopy"), enables very high sensitivity to be achieved even with very thin films or ultrahigh-purity material. The current knowledge about the identity of the residual shallow donors in GaAs, InP, InAs and InSb obtained with this technique is reviewed. With high-purity materials the magneto-optical spectrum of the shallow donors can be particularly rich and more than fifty lines can be observed with both GaAs and InP. Hydrostatic pressure provides a valuable additional experimental parameter in studies of impurities. Not only does the pressure-induced increase in mass improve the resolution of the "fine structure" due to different chemical species but additional states can be introduced into the forbidden energy gap. Results with both InSb and GaAs have shown that generally donors in direct-gap III-V materials may be expected to have three types of state: the familiar gamma-associated donors, localised states with A 1 symmetry which are normally resonant within the conduction band and metastable DX states. Negatively charged shallow donor states (D - states) and "molecular" combinations where the electrons are shared between two or more donor sites have been studied by infrared spectroscopy of III-V materials. These states are important precursors of the metal-insulator transition. Recently there have been a number of studies of impurities within quantum wells and heterostructures. The dependence of impurity energy on distance from the well edge has been established and it has been shown that high concentrations of D - states can be formed by remote deping of the structures.

  7. Far-Infrared Water Emissions from Magnetohydrodynamic Shock Waves

    NASA Technical Reports Server (NTRS)

    Kaufman, Michael J.; Neufeld, David A.

    1996-01-01

    Nondissociative, magnetohydrodynamic, C-type shock waves are expected to be a prodigious source of far-infrared water emissions in dense interstellar regions. We have constructed a model to calculate the farinfrared H20 line spectra that emerge from such shocks. Using the best estimates currently available for the radiative cooling rate and the degree of ion-neutral coupling within the shocked gas, we modeled the temperature structure of MHD shocks using standard methods in which the charged and neutral particles are treated separately as two weakly coupled, interpenetrating fluids. Then we solved the equations of statistical equilibrium to find the populations of the lowest 179 and 170 rotational states of ortho- and para-H2O We have completed an extensive parameter study to determine the emergent H2O line luminosities as a function of preshock density in the range n(H2) equals 10(exp 4) - 10(sup 6.5)/cc and shock velocity in the range upsilon(sub s) = 5 - 40 km/ s. We find that numerous rotational transitions of water are potentially observable using the Infrared Space Observatory and the Submillimeter Wave Astronomy Satellite and may be used as diagnostics of the shocked gas. We have also computed the rotational and ro-vibrational emissions expected from H2, CO, and OH, and we discuss how complementary observations of such emissions may be used to further constrain the shock conditions. In common with previous studies, we come close to matching the observed H2, and high-J CO emissions from the Orion-KL star-forming region on the basis of a single shock model. We present our predictions for the strengths of H2O line emission from the Orion shock, and we show how our results may be scaled to other regions where molecular shocks are likely to be present.

  8. Far-infrared line emission from high-redshift galaxies

    NASA Astrophysics Data System (ADS)

    Vallini, Livia; Gallerani, Simona; Ferrara, Andrea; Baek, Sunghye

    2013-08-01

    By combining high-resolution, radiative transfer cosmological simulations of z ≈ 6 galaxies with a subgrid multiphase model of their interstellar medium, we derive the expected intensity of several far-infrared emission lines ([C II] 158, [O I] 63 and [N II] 122 μm) for different values of the gas metallicity, Z. For Z = Z⊙, the [C II] spectrum is very complex due to the presence of several emitting clumps of individual sizes ≲3 kpc; the peak is displaced from the galaxy centre by ≈100 km s-1. While the [O I] spectrum is also similarly displaced, the [N II] line comes predominantly from the central ionized regions of the galaxy. When integrated over ˜ 500 km s- 1, the [C II] line flux is 185 mJy km s- 1; 95 per cent of such flux originates from the cold (T ≈ 250 K) H I phase and only 5 per cent from the warm (T ≈ 5000 K) neutral medium. The [O I] and [N II] fluxes are ˜6 and ˜90 times lower than the [C II] one, respectively. By comparing our results with observations of Himiko, the most extended and luminous Lyman alpha emitter at z = 6.6, we find that the gas metallicity in this source must be subsolar. We conclude that the [C II] line from z ≈ 6 galaxies is detectable by the ALMA full array in 1.9 < tON < 7.7 h observing time, depending on Z.

  9. A Hot-Electron Far-Infrared Direct Detector

    NASA Technical Reports Server (NTRS)

    Karasik, B. S.; McGrath, W. R.; LeDuc, H. G.

    2000-01-01

    A new approach is proposed to improve the sensitivity of direct-detection bolometers at millimeter, submillimeter and far-infrared wavelengths. The idea is to adjust a speed of the thermal relaxation of hot-electrons in a nanometer size normal metal or super-conductive transition edge bolometer by controlling the elastic electron mean free path. If the bolometer contacts are made of a superconductor with high critical temperature (Nb, Pb etc.) then the thermal diffusion into the contacts is absent because of the Andreev's reflection and the electron-phonon relaxation is the only mechanism for heat removal. The relaxation rate should behave as T(sup 4)l at subkelvin temperatures (l is the electron elastic mean free path) and can be reduced by factor of 10-100 by decreasing l. Then an antenna- or waveguide-coupled bolometer with a time constant about 10(exp -3) to 10(exp -5) s at T approximately equals 0.1-0.3 K will exhibit photon-noise limited performance in millimeter and submillimeter range. The choice of the bolometer material is a tradeoff between a low electron heat capacity and fabrication. A state-of-the-art bolometer currently offers NEP = 10(exp -17) W(Square root of (Hz)) at 100 mK along with a approximately equals 2 msec time constant. The bolometer we propose will have a figure-of-merit, NEP(square root (r)), which is 10(exp 3) times smaller. This will allow for a tremendous increase in speed which will have a significant impact for observational mapping applications. Alternatively, the bolometer could operate at higher temperature with still superior sensitivity. This device can significantly increase a science return and reduce the cost for future observational missions. This research was performed by the Center for Space Microelectronics Technology, Jet Propulsion Laboratory, California Institute of Technology, and was sponsored by NASA, Office of Space Science.

  10. A Hot-Electron Far-Infrared Direct Detector

    NASA Technical Reports Server (NTRS)

    Karasik, B. S.; McGrath, W. R.; LeDuc, H. G.

    2000-01-01

    A new approach is proposed to improve the sensitivity of direct-detection bolometers at millimeter, submillimeter and far-infrared wavelengths. The idea is to adjust a speed of the thermal relaxation of hot-electrons in a nanometer size normal metal or super-conductive transition edge bolometer by controlling the elastic electron mean free path. If the bolometer contacts are made of a superconductor with high critical temperature (Nb, Pb etc.) then the thermal diffusion into the contacts is absent because of the Andreev's reflection and the electron-phonon relaxation is the only mechanism for heat removal. The relaxation rate should behave as T(sup 4)l at subkelvin temperatures (l is the electron elastic mean free path) and can be reduced by factor of 10-100 by decreasing l. Then an antenna- or waveguide-coupled bolometer with a time constant about 10(exp -3) to 10(exp -5) s at T approximately equals 0.1-0.3 K will exhibit photon-noise limited performance in millimeter and submillimeter range. The choice of the bolometer material is a tradeoff between a low electron heat capacity and fabrication. A state-of-the-art bolometer currently offers NEP = 10(exp -17) W(Square root of (Hz)) at 100 mK along with a approximately equals 2 msec time constant. The bolometer we propose will have a figure-of-merit, NEP(square root (r)), which is 10(exp 3) times smaller. This will allow for a tremendous increase in speed which will have a significant impact for observational mapping applications. Alternatively, the bolometer could operate at higher temperature with still superior sensitivity. This device can significantly increase a science return and reduce the cost for future observational missions. This research was performed by the Center for Space Microelectronics Technology, Jet Propulsion Laboratory, California Institute of Technology, and was sponsored by NASA, Office of Space Science.

  11. The polarization of the far-infrared radiation from the Galactic center

    NASA Technical Reports Server (NTRS)

    Werner, M. W.; Davidson, J. A.; Morris, M.; Novak, G.; Platt, S. R.

    1988-01-01

    The first detection of linear polarization of the far-infrared (100-micron) radiation from the about 3-pc-diameter dust ring surrounding the galactic nucleus is reported. The percentage of polarization is between 1 and 2 percent at the three measured positions. It is argued that the polarized radiation is produced by thermal emission from elongated interstellar grains oriented by the local magnetic field. The dust ring is optically thin at 100 microns; therefore the observations sample dust through the entire depth of the cloud and are free of confusing effects due to embedded sources, scattering, or selective absorption. These data provide the first information about the configuration of the magnetic field in the dust ring.

  12. Infrared, Fourier transform far infrared spectroscopy, and viscosimetry research of aqueous-glycol fluids with thickener reology properties

    NASA Astrophysics Data System (ADS)

    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. Dark Field Microscopy for Analytical Laboratory Courses

    ERIC Educational Resources Information Center

    Augspurger, Ashley E.; Stender, Anthony S.; Marchuk, Kyle; Greenbowe, Thomas J.; Fang, Ning

    2014-01-01

    An innovative and inexpensive optical microscopy experiment for a quantitative analysis or an instrumental analysis chemistry course is described. The students have hands-on experience with a dark field microscope and investigate the wavelength dependence of localized surface plasmon resonance in gold and silver nanoparticles. Students also…

  14. Dark Field Microscopy for Analytical Laboratory Courses

    ERIC Educational Resources Information Center

    Augspurger, Ashley E.; Stender, Anthony S.; Marchuk, Kyle; Greenbowe, Thomas J.; Fang, Ning

    2014-01-01

    An innovative and inexpensive optical microscopy experiment for a quantitative analysis or an instrumental analysis chemistry course is described. The students have hands-on experience with a dark field microscope and investigate the wavelength dependence of localized surface plasmon resonance in gold and silver nanoparticles. Students also…

  15. Dark-field third-harmonic imaging

    NASA Astrophysics Data System (ADS)

    Doronina-Amitonova, L. V.; Lanin, A. A.; Fedotov, I. V.; Ivashkina, O. I.; Zots, M. A.; Fedotov, A. B.; Anokhin, K. V.; Zheltikov, A. M.

    2013-08-01

    Coherent cancellation of third-harmonic generation (THG) in a tightly focused laser beam is shown to enable a label-free imaging of individual neurons in representative brain tissues. The intrinsic coherence of third-harmonic buildup and cancellation combined with the nonlinear nature of the process enhances the locality of the dark signal in THG, translating into a remarkable sharpness of dark-field THG images. Unique advantages of this technique for high-contrast subcellular-resolution neuroimaging are demonstrated by comparing THG images of hippocampus and somatosensory cortex in a mouse brain with images visualizing fluorescent protein biomarkers.

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

    SciTech Connect

    Wardlow, Julie L.; Calanog, J.; Cooray, A.; Malhotra, S.; Zheng, Z.; Rhoads, J.; Finkelstein, S.; Bock, J.; Bridge, C.; Ciardullo, R.; Gronwall, C.; Conley, A.; Farrah, D.; Gawiser, E.; Heinis, S.; Ibar, E.; Ivison, R. J.; Marsden, G.; Oliver, S. J.; Riechers, D.; 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.

  17. The MPE/UCB Far-Infrared imaging Fabry-Perot Interferometer (FIFI)

    NASA Astrophysics Data System (ADS)

    Poglitsch, Albrecht; Beeman, J. W.; Geis, N.; Genzel, Reinhard; Haggerty, M.; Haller, E. E.; Jackson, J. M.; Rumitz, M.; Stacey, Gordon J.; Townes, Charles H.

    1990-12-01

    FIFI, an imaging spectrometer with two or three Fabry-Perot Interferometers (FPI) in series for airborne astronomical observations in the far infrared range (lambda = 40 to 200 microns) is described. It employs 5 by 5 arrays of photoconducting detectors and offers spectral resolutions as small as 2 km/s. Resolution and bandwidth can be set over a wide range to match a variety of astronomical sources. Cryogenic optics minimizes thermal background radiation and provides for inflight step tunable spatial resolution. At 158 microns wavelength the background limited NEP is 3 x 10-15 W/Hz at 40 km/s resolution and with two FPI's; with three FPI's the expected NEP is less than or = 10-15 W/Hz km/s resolution. The frequency shopping mode allows for line detection in extended objects. Absolute internal flux calibration ensures adequate flat fielding of the array elements.

  18. A Far Infrared Photometer (FIRP) for the infrared telescope in space (IRTS)

    NASA Technical Reports Server (NTRS)

    Freund, M. M.; Hirao, T.; Matsumoto, T.; Sato, S.; Watabe, T.; Brubaker, G. K.; Duband, L.; Grossman, B.; Larkin, N.; Lumetta, S.

    1993-01-01

    We describe the design and calibration of the Far-Infrared Photometer (FIRP), one of four focal plane instruments on the Infrared Telescope in Space (IRTS). The FIRP will provide absolute photometry in four bands centered at 150, 250, 400, and 700 micrometers with spectral resolution lambda/(Delta lambda) approx. = 3 and spatial resolution Delta theta = 0.5 degrees. High sensitivity is achieved by using bolometric detectors operated at 300 mK in an AC bridge circuit. The closed-cycle He-3 refrigerator can be recycled in orbit. A 2 K shutter provides a zero reference for each field of view. More than 10% of the sky will be surveyed during the approximately 3 week mission lifetime with a sensitivity of less than 10(exp -13) W/((sq cm)(sr)) per 0.5 degree pixel.

  19. The Interferometer As An Optical Mixer: A Novel Approach To Far Infrared Spectroscopy

    SciTech Connect

    Zerbini, M.; Franconi, E

    2008-03-12

    In Tokamaks, the Electron Cyclotron Emission (ECE) radiation frequency spans from 80 GHz up to 1 THz for high magnetic field (Bt>5 T) and higher harmonics (n>2). This frequency ranges between Microwaves and Far Infrared (FIR), moulding an intrinsically hybrid nature for ECE diagnostics{sup (1)}. Signal detection is carried out in two surprisingly different ways: electronics and optics. The two detection methods, beyond the chief external differences, are conceptually the same. The dualism often reflects the mindset of the laboratory performing the measurement. In this paper we discuss a different approach to an integrated instrument. A traditional quasi-optical interferometer is the first down-conversion stage with intrinsic broad band capability. Its output signal can then be analysed with a radio-style detection, in the amenable kHz frequency range.

  20. Far-infrared tangential interferometer/polarimeter design and installation for NSTX-U

    SciTech Connect

    Scott, E. R.; Barchfeld, R.; Riemenschneider, P.; Domier, C. W.; Sohrabi, M.; Luhmann, N. C.; Muscatello, C. M.; Kaita, R.; Ren, Y.

    2016-11-15

    The Far-infrared Tangential Interferometer/Polarimeter (FIReTIP) system has been refurbished and is being reinstalled on the National Spherical Torus Experiment—Upgrade (NSTX-U) to supply real-time line-integrated core electron density measurements for use in the NSTX-U plasma control system (PCS) to facilitate real-time density feedback control of the NSTX-U plasma. Inclusion of a visible light heterodyne interferometer in the FIReTIP system allows for real-time vibration compensation due to movement of an internally mounted retroreflector and the FIReTIP front-end optics. Real-time signal correction is achieved through use of a National Instruments CompactRIO field-programmable gate array.

  1. Far-infrared tangential interferometer/polarimeter design and installation for NSTX-U

    DOE PAGES

    Scott, E. R.; Barchfeld, R.; Riemenschneider, P.; ...

    2016-08-09

    Here, the Far-infrared Tangential Interferometer/Polarimeter (FIReTIP) system has been refurbished and is being reinstalled on the National Spherical Torus Experiment—Upgrade (NSTX-U) to supply real-time line-integrated core electron density measurements for use in the NSTX-U plasma control system (PCS) to facilitate real-time density feedback control of the NSTX-U plasma. Inclusion of a visible light heterodyne interferometer in the FIReTIP system allows for real-time vibration compensation due to movement of an internally mounted retroreflector and the FIReTIP front-end optics. Real-time signal correction is achieved through use of a National Instruments CompactRIO field-programmable gate array.

  2. Far-infrared properties of (TMTSF)/sub 2/ClO/sub 4/

    SciTech Connect

    Challener, W.A.; Richards, P.L.; Greene, R.L.

    1983-01-01

    The far-infrared properties of (TMTSF)/sub 2/ ClO/sub 4/ have been measured for frequencies between 4 and 40 cm/sup -1/. At 2K, phonon-like peaks in reflectance are seen at 7 and 29 cm/sup -1/. Increasing the temperature to 80K causes these peaks to gradually disappear, but not to shift appreciably in frequency. Radiation-induced defects substantially reduce the height of the 29 cm/sup -1/ peak with a magnetic field of up to 40 KG applied parallel to the C*-axis. These results suggest a coupled electronic-molecular vibration origin for these features. They are incompatible with the recently proposed /1/ interpretation of the 29 cm/sup -1/ feature as a quasi-one-dimensional superconductive pseudogap.

  3. Far-infrared intersubband photodetectors based on double-step III-nitride quantum wells

    NASA Astrophysics Data System (ADS)

    Sudradjat, Faisal F.; Zhang, Wei; Woodward, Jeffrey; Durmaz, Habibe; Moustakas, Theodore D.; Paiella, Roberto

    2012-06-01

    Far-infrared photoconductive detectors based on intersubband transitions in III-nitride semiconductor quantum wells are demonstrated. The device active material is based on a double-step quantum-well design, where two different (Al)GaN compositions are used both in the wells and in the barriers. With this approach, one can create a virtually flat multiple-quantum-well potential energy profile, where the deleterious effects of the intrinsic spontaneous and piezoelectric fields of nitride heterostructures are almost completely eliminated. Photocurrent spectra centered at a wavelength of 23 μm (13 THz frequency) are resolved up to 50 K, with responsivity of approximately 7 mA/W.

  4. The fine-structure intervals of (N-14)+ by far-infrared laser magnetic resonance

    NASA Technical Reports Server (NTRS)

    Brown, John M.; Varberg, Thomas D.; Evenson, Kenneth M.; Cooksy, Andrew L.

    1994-01-01

    The far-infrared laser magnetic resonance spectra associated with both fine-structure transitions in (N-14)+ in its ground P-3 state have been recorded. This is the first laboratory observation of the J = 1 left arrow 0 transition and its frequency has been determined two orders of magnitude more accurately than previously. The remeasurement of the J = 2 left arrow 1 spectrum revealed a small error in the previous laboratory measurements. The fine-structure splittings (free of hyperfine interactions) determined in this work are (delta)E(sub 10) = 1461.13190 (61) GHz, (delta)E(sub 21) = 2459.38006 (37) GHz. Zero-field transition frequencies which include the effects of hyperfine structure have also been calculated. Refined values for the hyperfine constants and the g(sub J) factors have been obtained.

  5. The Far-Infrared Photometer on the Infrared Telescope in Space

    NASA Technical Reports Server (NTRS)

    Lange, A. E.; Freund, M. M.; Sato, S.; Hirao, T.; Matsumoto, T.; Watabe, T.

    1994-01-01

    We describe the design and calibration of the Far-Infrared Photometer (FIRP), one of four focal plane instruments on the Infrared Telescope in Space (IRTS). The FIRP will provide absolute photometry in four bands centered at 150, 250, 400, and 700 microns with spectral resolution wavelength/wavelength spread is approximately 3 and spatial resolution delta theta = 0.5 degrees. High sensitivity is achieved by using bolometric detectors operated at 300 mK in an AC bridge circuit. The closed-cycle He-3 refrigerator can be recycled in orbit. A 2 K shutter provides a zero reference for each field of view. More than 10% of the sky will be surveyed during the 3 week mission lifetime with a sensitivity of less than 10(exp -13) W per sq cm per sr per 0.5 degree pixel.

  6. The Orion Nebula in the Far-Infrared: FIFI-LS/SOFIA Mapped the PDR

    NASA Astrophysics Data System (ADS)

    Klein, Randolf

    2016-01-01

    The Orion Nebula is the closest massive star forming region allowing us to study the physical conditions in such a region with high spatial resolution. We used the far infrared integral-field spectrometer, FIFI-LS, on-board the airborne observatory SOFIA to study the atomic and molecular gas in the Orion Nebula at medium spectral resolution. The large maps in several fine structure lines obtained with FIFI-LS cover the nebula from the BN/KL-object in the west to the bar in the south-east and gull feature in north-east. The fine structure lines can be used as a diagnostic for the physical conditions of the photon-dominated region (PDR), the interface between the HII-region and the molecular cloud.

  7. A Far Infrared Photometer (FIRP) for the infrared telescope in space (IRTS)

    NASA Technical Reports Server (NTRS)

    Freund, M. M.; Hirao, T.; Matsumoto, T.; Sato, S.; Watabe, T.; Brubaker, G. K.; Duband, L.; Grossman, B.; Larkin, N.; Lumetta, S.

    1993-01-01

    We describe the design and calibration of the Far-Infrared Photometer (FIRP), one of four focal plane instruments on the Infrared Telescope in Space (IRTS). The FIRP will provide absolute photometry in four bands centered at 150, 250, 400, and 700 micrometers with spectral resolution lambda/(Delta lambda) approx. = 3 and spatial resolution Delta theta = 0.5 degrees. High sensitivity is achieved by using bolometric detectors operated at 300 mK in an AC bridge circuit. The closed-cycle He-3 refrigerator can be recycled in orbit. A 2 K shutter provides a zero reference for each field of view. More than 10% of the sky will be surveyed during the approximately 3 week mission lifetime with a sensitivity of less than 10(exp -13) W/((sq cm)(sr)) per 0.5 degree pixel.

  8. Observations of downwelling far-infrared emission at Table Mountain California made by the FIRST instrument

    NASA Astrophysics Data System (ADS)

    Mlynczak, Martin G.; Cageao, Richard P.; Mast, Jeffrey C.; Kratz, David P.; Latvakoski, Harri; Johnson, David G.

    2016-02-01

    The Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument measured downwelling far-infrared (far-IR) and mid-infrared (mid-IR) atmospheric spectra from 200 to 800 cm-1 at Table Mountain, California (elevation 2285 m). Spectra were recorded during a field campaign conducted in early autumn 2012, subsequent to a detailed laboratory calibration of the instrument. Radiosondes launched coincident with the FIRST observations provide temperature and water vapor profiles for model simulation of the measured spectra. Results from the driest day of the campaign (October 19, with less than 3 mm precipitable water) are presented here. Considerable spectral development is observed between 400 and 600 cm-1. Over 90% of the measured radiance in this interval originates within 2.8 km of the surface. The existence of temperature inversions close to the surface necessitates atmospheric layer thicknesses as fine as 10 m in the radiative transfer model calculations. A detailed assessment of the uncertainties in the FIRST measurements and in the model calculations shows that the measured radiances agree with the model radiance calculations to within their combined uncertainties. The uncertainties in modeled radiance are shown to be larger than the measurement uncertainties. Overall, the largest source of uncertainty is in the water vapor concentration used in the radiative transfer calculations. Proposed new instruments with markedly higher measurement accuracy than FIRST will be able to measure the far-IR spectrum to much greater accuracy than it can be computed. As such, accurate direct measurements of the far-IR, and not solely calculations, are essential to the assessment of climate change.

  9. Far-infrared observations of an unbiased sample of gamma-ray burst host galaxies

    NASA Astrophysics Data System (ADS)

    Kohn, S. A.; Michałowski, M. J.; Bourne, N.; Baes, M.; Fritz, J.; Cooray, A.; De Looze, I.; De Zotti, G.; Dannerbauer, H.; Dunne, L.; Dye, S.; Eales, S.; Furlanetto, C.; Gonzalez-Nuevo, J.; Ibar, E.; Ivison, R. J.; Maddox, S. J.; Scott, D.; Smith, D. J. B.; Smith, M. W. L.; Symeonidis, M.; Valiante, E.

    2015-04-01

    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 20 BeppoSAX and Swift GRB host galaxies (at an average redshift of z = 3.1) located in the Herschel Astrophysical Terahertz Large Area Survey, the Herschel Virgo Cluster Survey, the Herschel Fornax Cluster Survey, the Herschel Stripe 82 Survey and the Herschel Multi-tiered Extragalactic Survey, totalling 880 deg2, or ˜3 per cent 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 Herschel survey - therefore our sample can be considered completely unbiased. Using deep data at wavelengths of 100-500 μm, we tentatively detected 1 out of 20 GRB hosts located in these fields. We constrain their dust masses and star formation rates (SFRs), and discuss these in the context of recent measurements of submillimetre galaxies and ultraluminous infrared galaxies. The average far-infrared flux of our sample gives an upper limit on SFR of <114 M⊙ yr-1. The detection rate of GRB hosts is consistent with that predicted assuming that GRBs trace the cosmic SFR density in an unbiased way, i.e. that the fraction of GRB hosts with SFR > 500 M⊙ yr-1 is consistent with the contribution of such luminous galaxies to the cosmic star formation density.

  10. Herschel-Astrophysical Terahertz Large Area Survey: detection of a far-infrared population around galaxy clusters

    NASA Astrophysics Data System (ADS)

    Coppin, K. E. K.; Geach, J. E.; Smail, Ian; Dunne, L.; Edge, A. C.; Ivison, R. J.; Maddox, S.; Auld, R.; Baes, M.; Buttiglione, S.; Cava, A.; Clements, D. L.; Cooray, A.; Dariush, A.; de Zotti, G.; Dye, S.; Eales, S.; Fritz, J.; Hopwood, R.; Ibar, E.; Jarvis, M.; Michałowski, M. J.; Murphy, D. N. A.; Negrello, M.; Pascale, E.; Pohlen, M.; Rigby, E.; Rodighiero, G.; Scott, D.; Serjeant, S.; Smith, D. J. B.; Temi, P.; van der Werf, P.

    2011-09-01

    We report the detection of a significant excess in the surface density of far-infrared sources from the Herschel-Astrophysical Terahertz Large Area Survey within ˜1 Mpc of the centres of 66 optically selected clusters of galaxies in the Sloan Digital Sky Survey with ˜ 0.25. From the analysis of the multiwavelength properties of their counterparts we conclude that the far-infrared emission is associated with dust-obscured star formation and/or active galactic nuclei (AGN) within galaxies in the clusters themselves. The excess reaches a maximum at a radius of ˜0.8 Mpc, where we find 1.0 ± 0.3 S250 > 34 mJy sources on average per cluster above what would be expected for random field locations. If the far-infrared emission is dominated by star formation (as opposed to AGN) then this corresponds to an average star formation rate of ˜7 M⊙ yr-1 per cluster in sources with LIR > 5 × 1010 L⊙. Although lensed sources make a negligible contribution to the excess signal, a fraction of the sources around the clusters could be gravitationally lensed, and we have identified a sample of potential cases of cluster-lensed Herschel sources that could be targeted in follow-up studies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

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

    SciTech Connect

    Cardozo, Benjamin Lewin

    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.

  12. High resolution far-infrared observations of the evolved H II region M16

    SciTech Connect

    McBreen, B.; Fazio, G.G.; Jaffe, D.T.

    1982-03-01

    M16 is an evolved, extremely density bounded H II region, which now consists only of a series of ionization fronts at molecular cloud boundaries. The source of ionization is the OB star cluster (NGC 6611) which is about 5 x 10/sup 6/ years old. We used the CFA/UA 102 cm balloon-borne telescope to map this region and detected three far-infrared (far-IR) sources embedded in an extended ridge of emission. Source I is an unresolved far-IR source embedded in a molecular cloud near a sharp ionization front. An H/sub 2/O maser is associated with this source, but no radio continuum emission has been observed. The other two far-IR sources (II and III) are associated with ionized gas-molecular cloud interfaces, with the far-IR radiation arising from dust at the boundary heated by the OB cluster. Source II is located at the southern prominent neutral intrusion with its associated bright rims and dark ''elephant trunk'' globules that delineate the current progress of the ionization front into the neutral material, and Source III arises at the interface of the northern molecular cloud fragment.

  13. Far-infrared pedestrian detection for advanced driver assistance systems using scene context

    NASA Astrophysics Data System (ADS)

    Wang, Guohua; Liu, Qiong; Wu, Qingyao

    2016-04-01

    Pedestrian detection is one of the most critical but challenging components in advanced driver assistance systems. Far-infrared (FIR) images are well-suited for pedestrian detection even in a dark environment. However, most current detection approaches just focus on pedestrian patterns themselves, where robust and real-time detection cannot be well achieved. We propose a fast FIR pedestrian detection approach, called MAP-HOGLBP-T, to explicitly exploit the scene context for the driver assistance system. In MAP-HOGLBP-T, three algorithms are developed to exploit the scene contextual information from roads, vehicles, and background objects of high homogeneity, and we employ the Bayesian approach to build a classifier learner which respects the scene contextual information. We also develop a multiframe approval scheme to enhance the detection performance based on spatiotemporal continuity of pedestrians. Our empirical study on real-world datasets has demonstrated the efficiency and effectiveness of the proposed method. The performance is shown to be better than that of state-of-the-art low-level feature-based approaches.

  14. Dark Field Microscopy for Analytical Laboratory Courses

    SciTech Connect

    Augspurger, Ashley E; Stender, Anthony S; Marchuk, Kyle; Greenbowe, Thomas J; Fang, Ning

    2014-06-10

    An innovative and inexpensive optical microscopy experiment for a quantitative analysis or an instrumental analysis chemistry course is described. The students have hands-on experience with a dark field microscope and investigate the wavelength dependence of localized surface plasmon resonance in gold and silver nanoparticles. Students also observe and measure individual crystal growth during a replacement reaction between copper and silver nitrate. The experiment allows for quantitative, qualitative, and image data analyses for undergraduate students.

  15. Structure formation with scalar field dark matter: the field approach

    SciTech Connect

    Magaña, Juan; Sánchez-Salcedo, F.J.; Matos, Tonatiuh; Suárez, Abril E-mail: tmatos@fis.cinvestav.mx E-mail: jsanchez@astro.unam.mx

    2012-10-01

    We study the formation of structure in the Universe assuming that dark matter can be described by a scalar field Φ-tilde with a potential V(Φ) = −m{sup 2}Φ-tilde {sup 2}/2+λΦ-tilde {sup 4}/4. We derive the evolution equations of the scalar field in the linear regime of perturbations. We investigate the symmetry breaking and possibly a phase transition of this scalar field in the early Universe. At low temperatures, the scalar perturbations have an oscillating growing mode and therefore, this kind of dark matter could lead to the formation of gravitational structures. In order to study the nonlinear regime, we use the spherical collapse model and show that, in the quadratic potential limit, this kind of dark matter can form virialized structures. The main difference with the traditional Cold Dark Matter paradigm is that the formation of structure in the scalar field model can occur at earlier times. Thus, if the dark matter behaves as a scalar field, large galaxies are expected to be formed already at high redshifts.

  16. Decaying Higgs Fields and Cosmological Dark Energy

    NASA Astrophysics Data System (ADS)

    Patla, B.; Nemiroff, R. J.

    2005-05-01

    The observed dark energy in the universe might give particles inertial mass. We investigate one realization of this idea, that the dark energy field might be a decayed scalar component of a scalar field in the early universe that creates inertial mass through spontaneous symmetry breaking, e.g. a Higgs field. To investigate this possibility, the cosmological Friedmann equation of energy balance is augmented in a standard way to incorporate a minimally coupled cosmological Higgs. For epochs where the expansion of the universe is driven by matter and radiation and not the scalar field, the observed hidden nature of the Higgs field can be codified into a single differential equation that we call the ``hidden higgs" condition. The resulting differential equation is solved for the time dependant scalar field and a simple and interesting solution is found analytically. Such a Higgs field decays from Planck scale energies rapidly and approximately exponentially from onset, leaving only the initially negligible constant term of the potential as a final cosmological constant. Such evolution replaces the hierarchy problem with the problem of explaining why such evolution is physically justified, leaving the coincidence problem still unresolved.

  17. Dark Field Imaging of Plasmonic Resonator Arrays

    NASA Astrophysics Data System (ADS)

    Aydinli, Atilla; Balci, Sinan; Karademir, Ertugrul; Kocabas, Coskun

    2012-02-01

    We present critical coupling of electromagnetic waves to plasmonic cavity arrays fabricated on Moir'e surfaces. The critical coupling condition depends on the superperiod of Moir'e surface, which also defines the coupling between the cavities. Complete transfer of the incident power can be achieved for traveling wave plasmonic resonators, which have relatively short superperiod. When the superperiod of the resonators increases, the coupled resonators become isolated standing wave resonators in which complete transfer of the incident power is not possible. Dark field plasmon microscopy imaging and polarization dependent spectroscopic reflection measurements reveal the critical coupling conditions of the cavities. We image the light scattered from SPPs in the plasmonic cavities excited by a tunable light source. Tuning the excitation wavelength, we measure the localization and dispersion of the plasmonic cavity mode. Dark field imaging has been achieved in the Kretschmann configuration using a supercontinuum white light laser equipped with an acoustooptic tunable filter. Polarization dependent spectroscopic reflection and dark field imaging measurements are correlated and found to be in agreement with FDTD simulations.

  18. Generation of tunable and broadband far-infrared laser pulses during two-color filamentation

    SciTech Connect

    Theberge, Francis; Chateauneuf, Marc; Roy, Gilles; Mathieu, Pierre; Dubois, Jacques

    2010-03-15

    Tunable far-infrared laser pulses were generated efficiently during two-color filamentation in air. Understanding the creation of few-cycle far-infrared laser pulses is important since it is at the frontier between two possible generation mechanisms. The first one is the four-wave mixing generation, associated to the generation of wavelengths from ultraviolet up to mid-infrared laser pulses. The second process is the formation of transient photocurrent, which was recently used to describe the generation of submillimetric (terahertz) waves. Comparison between experiments and simulations revealed that the four-wave mixing mechanism is dominant for the far-infrared generation during two-color filamentation.

  19. Scalar field dark matter and the Higgs field

    NASA Astrophysics Data System (ADS)

    Bertolami, O.; Cosme, Catarina; Rosa, João G.

    2016-08-01

    We discuss the possibility that dark matter corresponds to an oscillating scalar field coupled to the Higgs boson. We argue that the initial field amplitude should generically be of the order of the Hubble parameter during inflation, as a result of its quasi-de Sitter fluctuations. This implies that such a field may account for the present dark matter abundance for masses in the range 10-6-10-4eV, if the tensor-to-scalar ratio is within the range of planned CMB experiments. We show that such mass values can naturally be obtained through either Planck-suppressed non-renormalizable interactions with the Higgs boson or, alternatively, through renormalizable interactions within the Randall-Sundrum scenario, where the dark matter scalar resides in the bulk of the warped extra-dimension and the Higgs is confined to the infrared brane.

  20. The radio-far infrared correlation: Spiral and blue compact dwarf galaxies opposed

    NASA Technical Reports Server (NTRS)

    Klein, U.; Wunderlich, E.

    1987-01-01

    The recently established correlation between radio continuum and far infrared emission in galaxies was further investigated by comparing normal spiral and blue compact dwarf galaxies. The puzzling result is that the ratio of radio to far infrared luminosity and its dispersion is the same for both samples, although their ratios of blue to far infrared luminosity, their radio spectral indices and their dust temperatures exhibit markedly different mean values and dispersions. This suggests that the amount of energy radiated in the two regimes is enhanced in the same way although the mechanisms responsible for the two components are rather different and complex. The fact that the blue light does not increase at the same proportion shows that both the radio and the far infrared emission are connected with the recent star formation history.

  1. A spherical lamellar grating interferometer for airborne astronomical observations of far infrared objects

    NASA Technical Reports Server (NTRS)

    Pipher, J. L.; Savedoff, M. P.; Duthie, J. G.

    1976-01-01

    A lamellar grating has been developed to be used for very far infrared observations on the airborne observatory. The design characteristics and performance during laboratory testing and initial observations of Jupiter at wavelengths between 50 and 500 microns are presented.

  2. The far-infrared view of M87 as seen by the Herschel Space Observatory

    NASA Astrophysics Data System (ADS)

    Baes, M.; Clemens, M.; Xilouris, E. M.; Fritz, J.; Cotton, W. D.; Davies, J. I.; Bendo, G. J.; Bianchi, S.; Cortese, L.; De Looze, I.; Pohlen, M.; Verstappen, J.; Böhringer, H.; Bomans, D. J.; Boselli, A.; Corbelli, E.; Dariush, A.; di Serego Alighieri, S.; Fadda, D.; Garcia-Appadoo, D. A.; Gavazzi, G.; Giovanardi, C.; Grossi, M.; Hughes, T. M.; Hunt, L. K.; Jones, A. P.; Madden, S.; Pierini, D.; Sabatini, S.; Smith, M. W. L.; Vlahakis, C.; Zibetti, S.

    2011-02-01

    The origin of the far-infrared emission from the nearby radio galaxy M87 remains a matter of debate. Some studies find evidence of a far-infrared excess due to thermal dust emission, whereas others propose that the far-infrared emission can be explained by synchrotron emission without the need for an additional dust emission component. We observed M87 with PACS and SPIRE as part of the Herschel Virgo Cluster Survey (HeViCS). We compare the new Herschel data with a synchrotron model based on infrared, submm and radio data to investigate the origin of the far-infrared emission. We find that both the integrated SED and the Herschel surface brightness maps are adequately explained by synchrotron emission. At odds with previous claims, we find no evidence of a diffuse dust component in M87.

  3. Perturbations of ultralight vector field dark matter

    NASA Astrophysics Data System (ADS)

    Cembranos, J. A. R.; Maroto, A. L.; Núñez Jareño, S. J.

    2017-02-01

    We study the dynamics of cosmological perturbations in models of dark matter based on ultralight coherent vector fields. Very much as for scalar field dark matter, we find two different regimes in the evolution: for modes with {k}^2≪ Hma, we have a particle-like behaviour indistinguishable from cold dark matter, whereas for modes with {k}^2≫ Hma, we get a wave-like behaviour in which the sound speed is non-vanishing and of order c s 2 ≃ k 2/ m 2 a 2. This implies that, also in these models, structure formation could be suppressed on small scales. However, unlike the scalar case, the fact that the background evolution contains a non-vanishing homogeneous vector field implies that, in general, the evolution of the three kinds of perturbations (scalar, vector and tensor) can no longer be decoupled at the linear level. More specifically, in the particle regime, the three types of perturbations are actually decoupled, whereas in the wave regime, the three vector field perturbations generate one scalar-tensor and two vector-tensor perturbations in the metric. Also in the wave regime, we find that a non-vanishing anisotropic stress is present in the perturbed energy-momentum tensor giving rise to a gravitational slip of order ( Φ - Ψ)/ Φ ˜ c s 2 . Moreover in this regime the amplitude of the tensor to scalar ratio of the scalar-tensor modes is also h/ Φ ˜ c s 2 . This implies that small-scale density perturbations are necessarily associated to the presence of gravity waves in this model. We compare their spectrum with the sensitivity of present and future gravity waves detectors.

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

    NASA Technical Reports Server (NTRS)

    Meixner, M.; Cooray, A.; Carter, R.; DiPirro, M.; Flores, A.; Leisawitz, D.; Armus, L.; Battersby, C.; Bergin, E.; Bradford, C. M.; Ennico, K.; Milam, S.; Roellig. T.

    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.

  5. Stratospheric OH measurements with a far-infrared limb observing spectrometer

    NASA Technical Reports Server (NTRS)

    Pickett, H. M.; Peterson, D. B.

    1993-01-01

    The Far-Infrared Limb Observing Spectrometer (FILOS) is an instrument designed to measure the hydroxyl radical (OH) and other chemical species in the upper atmosphere using limb emission in the far-infrared region of the spectrum. FILOS uses three Fabry-Perot etalons in series to obtain high spectral resolution near 101/cm and 118/cm. The instrument concept, calibration, and atmospheric measurements are discussed.

  6. Stratospheric OH measurements with a far-infrared limb observing spectrometer

    NASA Astrophysics Data System (ADS)

    Pickett, H. M.; Peterson, D. B.

    1993-11-01

    The Far-Infrared Limb Observing Spectrometer (FILOS) is an instrument designed to measure the hydroxyl radical (OH) and other chemical species in the upper atmosphere using limb emission in the far-infrared region of the spectrum. FILOS uses three Fabry-Perot etalons in series to obtain high spectral resolution near 101 cm-1 and 118 cm-1. The instrument concept, calibration, and atmospheric measurements are discussed.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  9. Experimental studies of the far-infrared spectra of cosmic-type ices

    NASA Technical Reports Server (NTRS)

    Hudson, Reggie L.

    1992-01-01

    Work performed during the period is reported. The abstract of a paper presented at the Second International Workshop on the Nature of Cometary Organic Matter is included. Far infrared spectra of amorphous and crystalline water ice before and after proton irradiation is presented. Also, a study of clathrate hydrates was conducted in which a methanol (CH3OH) clathrate hydrate was prepared and its far-infrared spectrum investigated. This paper is also included.

  10. Far-infrared photometry of Titan and Iapetus

    SciTech Connect

    Loewenstein, R.F.; Harper, D.A.; Shaya, E.

    1980-01-01

    Titan was observed in four broad passbands between 35 and 150 microns. The brightness temperature in this interval is roughly constant at 76 plus or minus 3 K. Integrating Titan's spectrum from 5 to 150 microns yields an effective temperature of 86 plus or minus 3 K. Both the bright and dark hemispheres of Iapetus were observed in one broadband filter with a flux-weighted mean wavelength approximately equal to 66 microns. The brightness temperatures for these two sides of Iapetus are 96 plus or minus 9 K and 114 plus or minus 10 K, respectively. The bright-side Bond albedo is calculated to be 0.61(+0.16 -0.22).

  11. Use of the Far Infrared Tangential Interferometer/Polarimeter diagnostic for the study of rf driven plasma waves on NSTX.

    PubMed

    Kim, J; Lee, K C; Kaita, R; Phillips, C K; Domier, C W; Valeo, E; Luhmann, N C; Bonoli, P T; Park, H

    2010-10-01

    A rf detection system for waves in the 30 MHz range has been constructed for the Far Infrared Tangential Interferometer/Polarimeter on National Spherical Torus Experiment (NSTX). It is aimed at monitoring high frequency density fluctuations driven by 30 MHz high harmonic fast wave fields. The levels of density fluctuations at various radial chords and antenna phase angles can be estimated using the electric field calculated by TORIC code and linearized continuity equation for the electron density. In this paper, the experimental arrangement for the detection of rf signal and preliminary results of simulation will be discussed.

  12. The effective field theory of dark energy

    SciTech Connect

    Gubitosi, Giulia; Vernizzi, Filippo; Piazza, Federico E-mail: fpiazza@apc.univ-paris7.fr

    2013-02-01

    We propose a universal description of dark energy and modified gravity that includes all single-field models. By extending a formalism previously applied to inflation, we consider the metric universally coupled to matter fields and we write in terms of it the most general unitary gauge action consistent with the residual unbroken symmetries of spatial diffeomorphisms. Our action is particularly suited for cosmological perturbation theory: the background evolution depends on only three operators. All other operators start at least at quadratic order in the perturbations and their effects can be studied independently and systematically. In particular, we focus on the properties of a few operators which appear in non-minimally coupled scalar-tensor gravity and galileon theories. In this context, we study the mixing between gravity and the scalar degree of freedom. We assess the quantum and classical stability, derive the speed of sound of fluctuations and the renormalization of the Newton constant. The scalar can always be de-mixed from gravity at quadratic order in the perturbations, but not necessarily through a conformal rescaling of the metric. We show how to express covariant field-operators in our formalism and give several explicit examples of dark energy and modified gravity models in our language. Finally, we discuss the relation with the covariant EFT methods recently appeared in the literature.

  13. Cosmic Gauge-Field Dark Energy

    NASA Astrophysics Data System (ADS)

    Devulder, Christopher; Caldwell, Robert

    2017-01-01

    We present a cosmological model in which dark energy consists of a cosmic gauge field. At early times it behaves like radiation; at late times it drives cosmic acceleration. By varying the number of fields, their coupling strength and handedness, a wide range of behavior is shown to emerge. Joint constraints on the model from SNe, BAO and CMB data are presented. We discuss the possibility that the gauge field may seed a spectrum of primordial gravitational waves with a distinct imprint on the power spectrum, as well as act like a dissipative medium for high frequency gravitational waves. We show that this model could have an impact on the B-mode polarization pattern in the CMB, as well as future probes that use standard sirens to constrain the energy budget of the Universe.

  14. A CONDITIONAL LUMINOSITY FUNCTION MODEL OF THE COSMIC FAR-INFRARED BACKGROUND ANISOTROPY POWER SPECTRUM

    SciTech Connect

    De Bernardis, Francesco; Cooray, Asantha

    2012-11-20

    The cosmic far-infrared background (CFIRB) is expected to be generated by faint, dusty star-forming galaxies during the peak epoch of galaxy formation. The anisotropy power spectrum of the CFIRB captures the spatial distribution of these galaxies in dark matter halos and the spatial distribution of dark matter halos in the large-scale structure. Existing halo models of CFIRB anisotropy power spectrum either are incomplete or lead to halo model parameters that are inconsistent with the galaxy distribution selected at other wavelengths. Here, we present a conditional luminosity function approach to describe the far-IR bright galaxies. We model the 250 {mu}m luminosity function and its evolution with redshift and model-fit the CFIRB power spectrum at 250 {mu}m measured by the Herschel Space Observatory. We introduce a redshift-dependent duty cycle parameter so that we are able to estimate the typical duration of the dusty star formation process in the dark matter halos as a function of redshifts. We find that the duty cycle of galaxies contributing to the far-IR background is 0.3-0.5 with a dusty star formation phase lasting for {approx}0.3-1.6 Gyr. This result confirms the general expectation that the far-IR background is dominated by star-forming galaxies in an extended phase, not bright starbursts that are driven by galaxy mergers and last {approx}10-100 Myr. The halo occupation number for satellite galaxies has a power-law slope that is close to unity over 0 < z < 4. We find that the minimum halo mass for dusty, star-forming galaxies with L {sub 250} > 10{sup 10} L {sub Sun} is 2 Multiplication-Sign 10{sup 11} M {sub Sun} and 3 Multiplication-Sign 10{sup 10} M {sub Sun} at z = 1 and 2, respectively. Integrating over the galaxy population with L {sub 250} > 10{sup 9} L {sub Sun }, we find that the cosmic density of dust residing in the dusty, star-forming galaxies is responsible for the background anisotropies {Omega}{sub dust} {approx} 3 Multiplication-Sign 10{sup

  15. FAR-INFRARED PROPERTIES OF LYMAN BREAK GALAXIES FROM COSMOLOGICAL SIMULATIONS

    SciTech Connect

    Cen Renyue

    2011-12-15

    Utilizing state-of-the-art adaptive mesh refinement cosmological hydrodynamic simulations with ultra-high resolution (114 h{sup -1} pc) and a large sample size ({>=}3300 galaxies of stellar mass {>=}10{sup 9} M{sub Sun }), we show how the stellar light of Lyman break galaxies at z = 2 is distributed between optical/ultraviolet (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 M{sub Sun} yr{sup -1}) and extant FIR luminosity function at the bright end ({>=}20 M{sub Sun} yr{sup -1}). We quantify that galaxies more massive or having higher star formation rate (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 = 1-100 M{sub Sun} yr{sup -1} is a power law with a slope of about -1.7. We further predict that there is a 'galaxy desert' at SFR{sub FIR} < 0.02(SFR{sub UV}/10 M{sub Sun} yr{sup -1}){sup 2.1} M{sub Sun} yr{sup -1} in the SFR{sub UV} - SFR{sub FIR} plane. Detailed distributions of SFR{sub FIR} at a fixed SFR{sub UV} are presented. Upcoming observations by the Atacama Large Millimeter Array should test this model. If confirmed, it validates the predictions of the standard cold dark matter model and has important implications on the intrinsic SFR function of galaxies at high redshift.

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

    PubMed

    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.

  17. Germanium:gallium photoconductors for far infrared heterodyne detection

    NASA Technical Reports Server (NTRS)

    Park, I. S.; Haller, E. E.; Grossman, E. N.; Watson, Dan M.

    1988-01-01

    Highly compensated Ge:Ga photoconductors for high bandwidth heterodyne detection have been fabricated and evaluated. Bandwidths up to 60 MHz have been achieved with a corresponding current responsivity of 0.01 A/W. The expected dependence of bandwidth on bias field is obtained. It is noted that increased bandwidth is obtained at the price of greater required local oscillator power.

  18. Focal plane optics in far-infrared and submillimeter astronomy

    NASA Technical Reports Server (NTRS)

    Hildebrand, R. H.

    1985-01-01

    The construction of airborne observatories, high mountain-top observatories, and space observatories designed especially for infrared and submillimeter astronomy has opened fields of research requiring new optical techniques. A typical far-IR photometric study involves measurement of a continuum spectrum in several passbands between approx 30 microns and 1000 microns and diffraction-limited mapping of the source. At these wavelengths, diffraction effects strongly influence the design of the field optics systems which couple the incoming flux to the radiation sensors (cold bolometers). The Airy diffraction disk for a typical telescope at submillimeter wavelengths approx 100 microns-1000 microns is many millimeters in diameter; the size of the field stop must be comparable. The dilute radiation at the stop is fed through a Winston nonimaging concentrator to a small cavity containing the bolometer. The purpose of this paper is to review the principles and techniques of infrared field optics systems, including spectral filters, concentrators, cavities, and bolometers (as optical elements), with emphasis on photometric systems for wavelengths longer than 60 microns.

  19. Focal plane optics in far-infrared and submillimeter astronomy

    NASA Technical Reports Server (NTRS)

    Hildebrand, R. H.

    1986-01-01

    The construction of airborne observatories, high mountain-top observatories, and space observatories designed especially for infrared and submillimeter astronomy has opened fields of research requiring new optical techniques. A typical far-IR photometric study involves measurement of a continuum spectrum in several passbands between approx 30 microns and 1000 microns and diffraction-limited mapping of the source. At these wavelengths, diffraction effects strongly influence the design of the field optics systems which couple the incoming flux to the radiation sensors (cold bolometers). The Airy diffraction disk for a typical telescope at submillimeter wavelengths approx 100 microns-1000 microns is many millimeters in diameter; the size of the field stop must be comparable. The dilute radiation at the stop is fed through a Winston nonimaging concentrator to a small cavity containing the bolometer. The purpose of this paper is to review the principles and techniques of infrared field optics systems, including spectral filters, concentrators, cavities, and bolometers (as optical elements), with emphasis on photometric systems for wavelengths longer than 60 microns.

  20. Focal plane optics in far-infrared and submillimeter astronomy

    NASA Technical Reports Server (NTRS)

    Hildebrand, R. H.

    1986-01-01

    The construction of airborne observatories, high mountain-top observatories, and space observatories designed especially for infrared and submillimeter astronomy has opened fields of research requiring new optical techniques. A typical far-IR photometric study involves measurement of a continuum spectrum in several passbands between approx 30 microns and 1000 microns and diffraction-limited mapping of the source. At these wavelengths, diffraction effects strongly influence the design of the field optics systems which couple the incoming flux to the radiation sensors (cold bolometers). The Airy diffraction disk for a typical telescope at submillimeter wavelengths approx 100 microns-1000 microns is many millimeters in diameter; the size of the field stop must be comparable. The dilute radiation at the stop is fed through a Winston nonimaging concentrator to a small cavity containing the bolometer. The purpose of this paper is to review the principles and techniques of infrared field optics systems, including spectral filters, concentrators, cavities, and bolometers (as optical elements), with emphasis on photometric systems for wavelengths longer than 60 microns.

  1. A far-infrared mapping spectrometer for SOFIA

    NASA Astrophysics Data System (ADS)

    Nikola, Thomas; Stacey, Gordon J.; Herter, Terry

    2007-09-01

    We present a concept for a far-IR integral field spectrograph for SOFIA, the Cornell Mapping Spectrometer (CMS). CMS takes advantage of the next generation of large bolometer arrays to deliver moderate resolution spectroscopy in the wavelength range between 40 μm and 220 μm over a large field of view. Two separate wavelength channels with each employing six SCUBA-2-like bolometer arrays will provide 64 element spectra over a 10 × 12 spatial pixel footprint. By matching the pixel size to the beam size the field of view obtained is 190" × 160" at the important [CII] line in the long-λ channel and 77" × 64" at the [OI] line in the short-λ channel. The sliced image is fed into an R2 echelle spectrometer of modest resolving power (R ~ 2000). The grating will operate in 4th order at 158 μm in the long-λ channel and 4th order at 63 μm in the short-λ channel. This results in nearly matching orders for other important fine-structure lines of [NII] and [OIII]. Filterwheels are placed right in front of the detector arrays to separate the orders. By subdividing the detector assemblies and appropriately placing the 3 × 1 detector sub-assemblies it is possible to observe four fine-structure lines simultaneously. CMS combines the advantages of a FIFI-LS design (instantaneous spatial and spectral coverage) with the sensitivity advantage of bolometers over photo-conductors. This will make CMS the instrument of choice for deep spectroscopic integrations of extended regions in galaxies.

  2. Implications of charge ordering in high Tc cuprate superconductors in far-infrared spectroscopy.

    PubMed

    Kim, Y H; Hor, P H

    2013-09-04

    We addressed the issue of the absence of far-infrared signatures pertaining to charge ordering in the published far-infrared reflectivity data of La2-xSrxCuO4 single crystals while other experimental probes reveal that charge ordering is a hallmark of superconducting cuprates. Through direct comparison of the far-infrared data reported by various groups side by side and also with the Raman scattering data, we found that the inconsistencies stem from the failure in capturing delicate spectral features embedded in the close-to-perfect ab-plane far-infrared reflectivity of La2-xSrxCuO4 single crystals by misidentifying the reflectivity as the Drude-like metallic reflectivity. The analysis of the close-to-true reflectivity data reveals that only a small fraction (<3%) of the total doping-induced charge carriers (electrons) are itinerant on the electron lattice made up with the rest of the electrons (>97%) at all doping levels up to 16%. We conclude that the far-infrared reflectivity study is far from being ready to construct a coherent picture of the ubiquitous charge ordering phenomenon and its relationship with the high Tc superconductivity.

  3. The origin of the far-infrared luminosity within the spiral galaxy M101

    NASA Technical Reports Server (NTRS)

    Devereux, Nicholas A.; Scowen, Paul A.

    1994-01-01

    High resolution 60 and 100 micron images obtained with the Infared Astronomical Satellite (IRAS) are compared with H alpha images in order to investigate the origin of the far-infrared luminosity within the late-type spiral galaxy M101. There is a good correspondence between the far-infrared and H-alpha morphology. The far-infrared and H-alpha luminosities have been measured at 129 independent locations on the star forming disk of M101. After correcting the H-alpha luminosity for extinction and extrapolating the IRAS (40-120 microns) luminosity to 1000 microns we find that the far-infrared luminosity is commensurate with that expected from the O and B stars which are required to ionize the hydrogen gas, at all locations within M101. Additionally, the IRAS HiRes 60 and 100 micron images reveal that the dust temperature peaks coincide identically with the location of H II regions. The far-infrared luminosity of M101 is radiated primarily by dust with temperatures well in excess of that expected for cirrus, but similar to that observed for Galactic and extragalactic H II regions.

  4. Far-Infrared and Submillimeter Spectroscopy of Low to Moderate Redshift Normal and Active Galaxies

    NASA Technical Reports Server (NTRS)

    Fischer, Jacqueline

    2004-01-01

    Broadband surveys with planned observatories such as SIRTF, ASTRO-F, NGST, Herschel, SMA, and ALMA will provide large samples of dust-enshrouded galaxies undergoing varying proportions of star formation and accretion onto supermassive black holes. Recent evidence suggests that the mass of supermassive central black holes are proportional to central velocity dispersions of their host galaxy bulges, but it is not yet known how these properties are evolutionarily connected. To trace the evolution of these components during the important luminous, dusty merger episodes as a function of redshift, sensitive mid- to far-infrared spectroscopic diagnostic observations from space will be necessary. The high sensitivity and spatial resolution of a large aperture, natural background limited far-infrared/submillimeter telescope such as SAFAIR will allow detection and identification of the far-infrared/submillimeter components of galaxies and of a multitude of rest-frame mid- to far-infrared recombination, fine-structure, and molecular lines toward dusty galactic nuclei. The line diagnostics beginning to be developed from ISO work will help determine important parameters such as the intrinsic spectral energy distribution, ionization parameters, metallicities, densities, extinction to the embedded energy sources, and ultimately the star-formation and accretion rates in these galaxies. Ultimately, the higher spatial resolution provided by a cold, far-infrared submillimeter interferometer is needed to view the distribution of structure in galaxies in order to unravel the as yet untold story of the evolution of galaxies over the lifetime of the Universe.

  5. The Herschel Virgo Cluster Survey . VI. The far-infrared view of M 87

    NASA Astrophysics Data System (ADS)

    Baes, M.; Clemens, M.; Xilouris, E. M.; Fritz, J.; Cotton, W. D.; Davies, J. I.; Bendo, G. J.; Bianchi, S.; Cortese, L.; De Looze, I.; Pohlen, M.; Verstappen, J.; Böhringer, H.; Bomans, D. J.; Boselli, A.; Corbelli, E.; Dariush, A.; di Serego Alighieri, S.; Fadda, D.; Garcia-Appadoo, D. A.; Gavazzi, G.; Giovanardi, C.; Grossi, M.; Hughes, T. M.; Hunt, L. K.; Jones, A. P.; Madden, S.; Pierini, D.; Sabatini, S.; Smith, M. W. L.; Vlahakis, C.; Zibetti, S.

    2010-07-01

    The origin of the far-infrared emission from the nearby radio galaxy M 87 remains a matter of debate. Some studies find evidence of a far-infrared excess due to thermal dust emission, whereas others propose that the far-infrared emission can be explained by synchrotron emission without the need for an additional dust emission component. We present Herschel PACS and SPIRE observations of M 87, taken as part of the science demonstration phase observations of the Herschel Virgo Cluster Survey. We compare these data with a synchrotron model based on mid-infrared, far-infrared, submm and radio data from the literature to investigate the origin of the far-infrared emission. Both the integrated SED and the Herschel surface brightness maps are adequately explained by synchrotron emission. At odds with previous claims, we find no evidence of a diffuse dust component in M 87, which is not unexpected in the harsh X-ray environment of this radio galaxy sitting at the core of the Virgo cluster. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  6. Far infrared spectrum of Methanol-D2 in the lowest torsional state (e0)

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Indra

    2016-03-01

    The infrared (IR) and far infrared (FIR) absorption spectra have been measured for the Methanol-D1 and D2 species in the wave number range of 20-1200 cm-1 at the Justus Liebig Universität in Giessen, Germany using a Brüker Fourier Transform spectrometer at a resolution of 0.002 cm-1. The spectra looked very complicated but analyses were possible for the lower lying states. At higher wave number regions spectra of few vibrational fundamental modes were visible. In this communication, the details of the assignments and analyses of the lowest lying internal rotational state (e0) for Methanol-D2 are reported. A catalog of about 900 assigned spectral lines has been prepared and is made available from the author to conserve space. As application of this work, it was possible to assign some optically pumped FIR laser lines to quantum states. The results should be useful for "radio astronomers" and in the field of optically pumped FIR and Sub-millimeter Wave (SMMW) lasers which are used in Tokamaks for plasma diagnostics and as local oscillators in radio detection from space.

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

    SciTech Connect

    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. MID- AND FAR-INFRARED PROPERTIES OF A COMPLETE SAMPLE OF LOCAL ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Ichikawa, Kohei; Ueda, Yoshihiro; Terashima, Yuichi; Oyabu, Shinki; Gandhi, Poshak; Nakagawa, Takao; Matsuta, Keiko

    2012-07-20

    We investigate the mid- (MIR) to far-infrared (FIR) properties of a nearly complete sample of local active galactic nuclei (AGNs) detected in the Swift/Burst Alert Telescope (BAT) all-sky hard X-ray (14-195 keV) survey, based on the cross correlation with the AKARI infrared survey catalogs complemented by those with Infrared Astronomical Satellite and Wide-field Infrared Survey Explorer. Out of 135 non-blazer AGNs in the Swift/BAT nine-month catalog, we obtain the MIR photometric data for 128 sources either in the 9, 12, 18, 22, and/or 25 {mu}m band. We find good correlation between their hard X-ray and MIR luminosities over three orders of magnitude (42 < log {lambda}L{sub {lambda}}(9, 18 {mu}m) < 45), which is tighter than that with the FIR luminosities at 90 {mu}m. This suggests that thermal emission from hot dusts irradiated by the AGN emission dominate the MIR fluxes. Both X-ray unabsorbed and absorbed AGNs follow the same correlation, implying isotropic infrared emission, as expected in clumpy dust tori rather than homogeneous ones. We find excess signals around 9 {mu}m in the averaged infrared spectral energy distribution from heavy obscured 'new type' AGNs with small scattering fractions in the X-ray spectra. This could be attributed to the polycyclic aromatic hydrocarbon emission feature, suggesting that their host galaxies have strong starburst activities.

  9. Semiconductor detectors and focal plane arrays for far-infrared imaging

    NASA Astrophysics Data System (ADS)

    Rogalski, A.

    2013-12-01

    The detection of far-infrared (far-IR) and sub-mm-wave radiation is resistant to the commonly employed techniques in the neighbouring microwave and IR frequency bands. In this wavelength detection range the use of solid state detectors has been hampered for the reasons of transit time of charge carriers being larger than the time of one oscillation period of radiation. Also the energy of radiation quanta is substantially smaller than the thermal energy at room temperature and even liquid nitrogen temperature. The realization of terahertz (THz) emitters and receivers is a challenge because the frequencies are too high for conventional electronics and the photon energies are too small for classical optics. Development of semiconductor focal plane arrays started in seventies last century and has revolutionized imaging systems in the next decades. This paper presents progress in far-IR and sub-mm-wave semiconductor detector technology of focal plane arrays during the past twenty years. Special attention is given on recent progress in the detector technologies for real-time uncooled THz focal plane arrays such as Schottky barrier arrays, field-effect transistor detectors, and microbolometers. Also cryogenically cooled silicon and germanium extrinsic photoconductor arrays, and semiconductor bolometer arrays are considered.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Fringe jump analysis and electronic corrections for the Tore Supra far infrared interferometer.

    PubMed

    Gil, C; Barbuti, A; Elbèze, D; Pastor, P; Philip, J; Toulouse, L

    2008-10-01

    On the Tore Supra tokamak, the ten-channel far infrared interferometer consists of a double color (119 and 195 microm) system with two detectors for each channel to measure the plasma density. The phase measurement is obtained by combining a 100 kHz shifted reference beam with the probing beam that has crossed the plasma. The achieved precision--a few percent of a fringe--is very good compared with the expected variations due to plasma, which are on the order of several fringes. However, the counting of the fringe variations can be affected when the signal is perturbed by electromagnetic interferences or when it deviates in the presence of strong plasma refraction changes occurring during ICRH breakdowns, pellet injections, or disruptions. This induces a strong decrease in the reliability of the measurement, which is an important concern when the diagnostic is used for density control. We describe in this paper the renewing of the electronics that has been achieved to reduce and correct the number of the so-called fringe jumps. A new zero crossing method for phase measurement is used, together with a field programmable gate array semiconductor integration, to measure the phase and activate the algorithm of corrections every 10 micros. Comparisons between a numerical oscilloscope analysis and the corrected acquired data in the case of laboratory amplitude modulation tests and in the case of real plasma perturbations are also discussed.

  13. Monitoring the Far Infrared Variability of Deeply Embedded Protostars with SOFIA/HAWC

    NASA Astrophysics Data System (ADS)

    Johnstone, Doug

    2015-10-01

    Low-mass stars form via gravitational collapse of molecular cloud cores. The evolution of the mass accretion onto a forming protostar depends on the rate at which the interior of the core collapses, the significance of a circumstellar disk as a temporary mass reservoir, and the physics of how the gas is transported through the disk and accretes onto the central star. Despite a clear requirement for time dependency in the accretion rate onto deeply embedded protostars and a large number of theoretical mechanisms for powering variability, our understanding of both the timescale and amplitude of variability is almost entirely unconstrained. The bolometric luminosity of deeply embedded protostars is a direct proxy for the accretion luminosity, modified only by the addition of the stellar luminosity itself. For deeply embedded protostars, the spectral energy distribution peaks in the far infrared, near 100 microns, making this an ideal wavelength for long-term monitoring of accretion variability. We propose to use SOFIA/HAWC at 89 and 154 microns to monitor three star-forming fields (Cepheus, Perseus, and Serpens) as part of a long-term campaign dedicated to uncovering the observational signature of episodic accretion. These observations will aid in our understanding of how stars accumulate their final mass and are neceassry for discriminating between the various theoretical models of episodic accretion onto deeply embedded protostars.

  14. FAR-INFRARED IMAGING OF POST-ASYMPTOTIC GIANT BRANCH STARS AND (PROTO)-PLANETARY NEBULAE WITH THE AKARI FAR-INFRARED SURVEYOR

    SciTech Connect

    Cox, N. L. J.; Garcia-Hernandez, D. A.; Manchado, A.

    2011-04-15

    By tracing the distribution of cool dust in the extended envelopes of post-asymptotic giant branch stars and (proto)-planetary nebulae ((P)PNe), we aim to recover, or constrain, the mass-loss history experienced by these stars in their recent past. The Far-Infrared Surveyor (FIS) instrument on board the AKARI satellite was used to obtain far-infrared maps for a selected sample of post-AGB stars and (P)PNe. We derived flux densities (aperture photometry) for 13 post-AGB stars and (P)PNe at four far-infrared wavelengths (65, 90, 140, and 160 {mu}m). Radial (azimuthally averaged) profiles are used to investigate the presence of extended emission from cool dust. No (detached) extended emission is detected for any target in our sample at levels significant with respect to background and cirrus emission. Only IRAS 21046+4739 reveals tentative excess emission between 30'' and 130''. Estimates of the total dust and gas mass from the obtained maps indicate that the envelope masses of these stars should be large in order to be detected with the AKARI FIS. Imaging with higher sensitivity and higher spatial resolution is needed to detect and resolve, if present, any cool compact or extended emission associated with these evolved stars.

  15. Status of far infrared tangential interferometry/polarimetry system on NSTX (abstract)

    NASA Astrophysics Data System (ADS)

    Park, H.; Deng, B.; Domier, C. W.; Johnson, M.; Luhmann, N. C.

    2001-01-01

    Measurement of the core BT(r,t) value is essential in National Spherical Torus Experiment (NSTX), since effects of paramagnetism and diamagnetism in the Spherical Torus are expected to be considerably greater than that in higher aspect ratio tokamaks. Therefore, plasma parameters dependent upon BT such as the q-profile and local q value cannot be evaluated without independent measurement of BT(r,t). The multichord tangential far infrared interferometer/polarimeter (FIReTIP) system currently under development for NSTX will provide temporally and radially resolved toroidal field profile [BT(r,t)] and two-dimensional (2D) electron density profile [ne(r,t)] data. The seven channel system is based on three FIR lasers including the Stark tuned FIR laser operating at 119 μm which is an optimum wavelength for NSTX plasma parameters. The optical system is configured as a Michelson system using retroreflectors. The final system design is completed and initial two channels will be installed this fiscal year to support NSTX operation. The channel spacing of FIReTIP system is optimized via data analysis with various expected electron density and magnetic field profile shapes. In simulation study, the solution of self-consistent magnetohydrodynamics equilibrium was used to project a diamagnetic effect on the toroidal magnetic field. A detailed inversion process based on assumed profiles of the electron density and self-consistent toroidal field is exercised to estimate the source of errors for both local density and local magnetic field. The outcome of the proposed system is crucial to the study of confinement, heating and stability of NSTX plasmas.

  16. Self-interacting complex scalar field as dark matter

    SciTech Connect

    Briscese, F.

    2011-10-14

    We study the viability of a a complex scalar field {chi} with self-interacting potential V = m{sub 0}{sup {chi}/}2|{chi}|{sup 2}+h|{chi}|{sup 4} as dark matter. Due to the self interaction, the scalar field forms a Bose-Einstein condensate at early times that represents dark matter. The self interaction is also responsible of quantum corrections to the scalar field mass that naturally give the dark matter domination at late times without any fine tuning on the energy density of the scalar field at early times. Finally the properties of the spherically symmetric dark matter halos are also discussed.

  17. The nature of unidentified far-infrared point sources

    NASA Technical Reports Server (NTRS)

    Reach, William T.; Heiles, Carl; Koo, Bon-Chul

    1993-01-01

    Sources discovered by the Infrared Astronomical Satellite with spectra that rise steeply from 60 to 100 microns are a mixed sample of external galaxies, condensations in the interstellar medium, and potentially unknown astronomical objects. Sources in regions of low total H I column density (as determined with the all-sky 21-cm line surveys), and with no nearby cataloged external galaxy, were observed for presence of 20-cm continuum emission (with the NRAO VLA), enhanced 21-cm H I line emission (with the NAIC Arecibo 305 m), and molecular line emission (with the NRAO 12 m, HCRO 6 m, and FCRAO 14 m). Based on the CO detection rate, 70 percent of our sample are small interstellar molecular clouds. The remainder are mostly faint external galaxies. The dust column densities of the interstellar condensations were determined from the IR flux, using a spherical-cloud model for the radiative transfer of the interstellar radiation field (ISRF). The CO column densities were determined using the large-velocity-gradient model for the excitation and radiative transfer of the rotational transitions. About half of the interstellar sources have normal dust-to-gas ratios and ISRF heating. Sources with excess infrared emission, compared to the molecular column density, are protostellar candidates.

  18. Far-Infrared Spectral Observations of the Galaxy by COBE

    SciTech Connect

    Reach, W.T.; Dwek, E.; Fixsen, D.J.; Hewagama, T.; Mather, J.C.; Shafer, R.A.; Banday, A.J.; Bennett, C.L.; Cheng, E.S.; Eplee Jr., R.E.,; Leisawi tz, D.; Lubin, P.M.; Read, S.M.; Rosen, L.P.; Shuman, F.G.D.; Smoot, G.F.; Sodroski, T.J.; Wright, E.L.

    1994-10-27

    We derive Galactic continuum spectra from 5-96 cm(-1) fromCOBE/FIRAS observations. The spectra are dominated by warm dust emission,which may be fitted with a single temperature in the range 16-21 K (fornu(2) emissivity) along each line of sight. Dust heated by the attenuatedradiation field in molecular clouds gives rise tointermediate-temperature (10-14 K) emission in the inner Galaxy only. Awidespread, very cold component (4-7 K) with optical depth that isspatially correlated with the warm component is also detected. The coldcomponent is unlikely to be due to very cold dust shielded from starlightbecause it is present at high latitude. We consider hypotheses that thecold component is due to enhanced submillimeter emissivity of the dustthat gives rise to the warm component, or that it may be due to verysmall, large, or fractal particles. Lack of substantial power above theemission from warm dust places strong constraints on the amount of coldgas in the Galaxy. The microwave sky brightness due to interstellar dustis dominated by the cold component, and its angular variation could limitour ability to discern primordial fluctuations in the cosmic microwavebackground radiation.

  19. Far-infrared investigations of the surface modes in CdS thin films

    NASA Astrophysics Data System (ADS)

    Trajić, J.; Gilić, M.; Romčević, N.; Romčević, M.; Stanišić, G.; Lazarević, Z.; Joksimović, D.; Yahia, I. S.

    2014-09-01

    The properties of Cadmium sulphide (CdS) thin films were investigated by applying atomic force microscopy (AFM) and far-infrared spectroscopy. CdS thin films were prepared using thermal evaporation technique under a base pressure of 2 × 10-5 torr. The quality of these films was investigated by AFM spectroscopy. We apply far-infrared spectroscopy to investigate the optical properties of CdS thin films, and reveal the existence of a surface optical phonon (SOP) mode at 297 cm-1. For the first time, the dielectric function of CdS thin film is modeled as a mixture of homogenous spherical inclusions in air by the Maxwell-Garnet formula. In the analysis of the far-infrared reflection spectra, a numerical model for calculating the reflectivity coefficient for a system which includes films and substrates has been applied.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  2. Method for generation of tunable far infrared radiation from two-dimensional plasmons

    NASA Technical Reports Server (NTRS)

    Katz, Joseph (Inventor)

    1989-01-01

    Tunable far infrared radiation is produced from two-dimensional plasmons in a heterostructure, which provides large inversion-layer electron densities at the heterointerface, without the need for a metallic grating to couple out the radiation. Instead, a light interference pattern is produced on the planar surface of the heterostructure using two coherent laser beams of a wavelength selected to be strongly absorbed by the heterostructure in order to penetrate through the inversion layer. The wavelength of the far infrared radiation coupled out can then be readily tuned by varying the angle between the coherent beams, or varying the wavelength of the two interfering coherent beams, thus varying the periodicity of the photoconductivity grating to vary the wavelength of the far infrared radiation being coupled out.

  3. Charting the Winds that Change the Universe, II: The Single Aperture Far Infrared Observatory (SAFIR)

    NASA Technical Reports Server (NTRS)

    Rieke, G. H.; Benford, D. J.; Harvey, P. M.; Lawrence, C. R.; Leisawitz, D. T.; Lester, D. F.; Mather, J. C.; Stacey, G. J.; Werner, M. W.; Yorke, H. W.

    2004-01-01

    SAFIR will study the birth and evolution of stars and planetary systems so young that they are invisible to optical and near-infrared telescopes such as NGST. Not only does the far-infrared radiation penetrate the obscuring dust clouds that surround these systems, but the protoplanetary disks also emit much of their radiation in the far infrared. Furthermore, the dust reprocesses much of the optical emission from the newly forming stars into this wavelength band. Similarly, the obscured central regions of galaxies, which harbor massive black holes and huge bursts of star formation, can be seen and analyzed in the far infrared. SAFIR will have the sensitivity to see the first dusty galaxies in the universe. For studies of both star-forming regions in our galaxy and dusty galaxies at high redshifts, SAFIR will be essential in tying together information that NGST will obtain on these systems at shorter wavelengths and that ALMA will obtain at longer wavelengths.

  4. Mechanism of the Far-Infrared Absorption of Carbon-Nanotube Films

    NASA Astrophysics Data System (ADS)

    Kampfrath, T.; von Volkmann, K.; Aguirre, C. M.; Desjardins, P.; Martel, R.; Krenz, M.; Frischkorn, C.; Wolf, M.; Perfetti, L.

    2008-12-01

    The far-infrared conductivity of single-wall carbon-nanotube ensembles is dominated by a broad absorption peak around 4 THz whose origin is still debated. We observe an overall depletion of this peak when the nanotubes are excited by a short visible laser pulse. This finding excludes optical absorption due to a particle-plasmon resonance and instead shows that interband transitions in tubes with an energy gap of ˜10meV dominate the far-infrared conductivity. A simple model based on an ensemble of two-level systems naturally explains the weak temperature dependence of the far-infrared conductivity by the tube-to-tube variation of the chemical potential.

  5. Two views of the Andromeda Galaxy H-alpha and far infrared

    NASA Technical Reports Server (NTRS)

    Devereux, Nicholas A.; Price, Rob; Wells, Lisa A.; Duric, Neb

    1994-01-01

    A complete H-alpha image of the Andromeda Galaxy (M31) is presented allowing the first direct measurement of the total H-alpha luminosity which is (7.3 +/- 2.4) x 10(exp 6) solar luminosity. The H-alpha emission is associated with three morphologically distinct components; a large scale star-forming ring, approximately 1.65 deg in diameter, contributing 66% of the total H-alpha emission, a bright nucleus contributing 6% of the total H-alpha emission with the remaining 28% contributed by a previously unidentified component of extended and filamentary H-alpha emission interior to the star forming ring. The correspondence between the H-alpha image and the Infrared Astronomy Satellite (IRAS) far-infrared high resolution image is striking when both are convolved to a common resolution of 105 arcsec. The close correspondence between the far-infrared and H-alpha images suggests a common origin for the two emissions. The star-forming ring contributes 70% of the far-infrared luminosity of M31. Evidence that the ring emission is energized by high mass stars includes the fact that peaks in the far-infrared emission coincide identically with H II regions in the H-alpha image. In addition, the far-infrared to H-alpha luminosity ratio within the star-forming ring is similar to what one would expect for H II regions powered by stars of spectral types ranging between O9 and B0. The origin of the filamentary H-alpha and far-infrared luminosity interior to the star-forming ring is less clear, but it is almost certainly not produced by high mass stars.

  6. Heterodyne Receiver Requirements for the Single Aperture Far-Infrared (SAFIR) Observatory

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J.; Kooi, Jacob; Oegerle, William (Technical Monitor)

    2003-01-01

    In the next few years, work will commence in earnest on the development of technology for the next generation large cryogenic far-infrared telescope: the Single Aperture Far- Infrared (SAFIR) Observatory. SAFIR's science goals are driven by the fact that youngest stages of almost all phenomena in the universe are shrouded in absorption by cool dust, resulting in the energy being emitted primarily in the far-infrared. The earliest stages of star formation, when gas and dust clouds are collapsing and planets forming, can only be observed in the far-infrared. Spectral diagnostics in the far-infrared are typically quite narrow (approx. 1 km/s) and require high sensitivity to detect them. SAFIR is a 10 m-class telescope designed for cryogenic operation at L2, removing all sources of thermal emission from the telescope and atmosphere. Despite its limited collecting area and angular resolution as compared to the ALMA interferometer, its potential for covering the entire far-infrared band cannot be matched by any ground-based or airborne observatory. This places a new challenge on heterodyne receivers: broad frequency coverage. The ideal mixer would be able to detect frequencies over several octaves (e.g., 0.6 THz - 12 THz) with near quantum-limited performance at all frequencies. In contrast to ground-based observatories, it may not be necessary to strive for high instantaneous bandwidth, as direct detection spectroscopy is preferable for bandwidths of Delta v/ v greater than or equal to 10(exp -4) (e.g., 1 GHz at 10 THz). We consider likely directions for technology development for heterodyne receivers for SAFIR.

  7. Fine-scale structure in the far-infrared Milky-Way

    NASA Technical Reports Server (NTRS)

    Waller, William H.; Wall, William F.; Reach, William T.; Varosi, Frank; Ebert, Rick; Laughlin, Gaylin; Boulanger, Francois

    1995-01-01

    This final report summarizes the work performed and which falls into five broad categories: (1) generation of a new data product (mosaics of the far-infrared emission in the Milky Way); (2) acquisition of associated data products at other wavelengths; (3) spatial filtering of the far-infrared mosaics and resulting images of the FIR fine-scale structure; (4) evaluation of the spatially filtered data; (5) characterization of the FIR fine-scale structure in terms of its spatial statistics; and (6) identification of interstellar counterparts to the FIR fine-scale structure.

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

    DOEpatents

    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.

  9. Evidence for a variable far-infrared source in NGC 6334

    NASA Technical Reports Server (NTRS)

    Mcbreen, B.; Fazio, G. G.; Stier, M.; Wright, E. L.

    1979-01-01

    NGC 6334 has been mapped with a 40-250 micron photometer with 1 arcmin resolution. Six sources of far-infrared radiation have been detected. The second-strongest source was not detected in an earlier (2.7 years) 40-350 micron survey of the same region. This source is interpreted as a variable far-infrared source. The new source, located at the position of OH and H2O maser sources, is extended (0.7 arcmin FWHM) and has a bolometric luminosity of 190,000 solar luminosities and may represent a hitherto unobserved transient stage of protostellar collapse.

  10. Triple unification of inflation, dark matter, and dark energy using a single field

    SciTech Connect

    Liddle, Andrew R.; Pahud, Cedric; Urena-Lopez, L. Arturo

    2008-06-15

    We construct an explicit scenario whereby the same material driving inflation in the early universe can comprise dark matter in the present universe, using a simple quadratic potential. Following inflation and preheating, the density of inflaton/dark matter particles is reduced to the observed level by a period of thermal inflation, of a duration already invoked in the literature for other reasons. Within the context of the string landscape, one can further argue for a nonzero vacuum energy of this field, thus unifying inflation, dark matter, and dark energy into a single fundamental field.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. The Physics of the Far-infrared-Radio Correlation. I. Calorimetry, Conspiracy, and Implications

    NASA Astrophysics Data System (ADS)

    Lacki, Brian C.; Thompson, Todd A.; Quataert, Eliot

    2010-07-01

    The far-infrared (FIR) and radio luminosities of star-forming galaxies are linearly correlated over a very wide range in star formation rate, from normal spirals like the Milky Way to the most intense starbursts. Using one-zone models of cosmic ray (CR) injection, cooling, and escape in star-forming galaxies, we attempt to reproduce the observed FIR-radio correlation (FRC) over its entire span. The normalization and linearity of the FRC, together with constraints on the CR population in the Milky Way, have strong implications for the CR and magnetic energy densities in star-forming galaxies. We show that for consistency with the FRC, ~2% of the kinetic energy from supernova explosions must go into high-energy primary CR electrons and that ~10%-20% must go into high-energy primary CR protons. Secondary electrons and positrons are likely comparable to or dominate primary electrons in dense starburst galaxies. We discuss the implications of our models for the magnetic field strengths of starbursts, the detectability of starbursts by Fermi, and CR feedback. Overall, our models indicate that both CR protons and electrons escape from low surface density galaxies, but lose most of their energy before escaping dense starbursts. The FRC is caused by a combination of the efficient cooling of CR electrons (calorimetry) in starbursts and a conspiracy of several factors. For lower surface density galaxies, the decreasing radio emission caused by CR escape is balanced by the decreasing FIR emission caused by the low effective UV dust opacity. In starbursts, bremsstrahlung, ionization, and inverse Compton cooling decrease the radio emission, but they are countered by secondary electrons/positrons and the dependence of synchrotron frequency on energy, both of which increase the radio emission. Our conclusions hold for a broad range of variations in our fiducial model, such as those including winds, different magnetic field strengths, and different diffusive escape times.

  13. Terahertz dark-field imaging of biomedical tissue

    NASA Astrophysics Data System (ADS)

    Löffler, Torsten; Bauer, T.; Siebert, Karsten; Roskos, Hartmut G.; Fitzgerald, A.; Czasch, S.

    2001-12-01

    We investigate dark-field imaging in the terahertz (THz) fre-quency regime with the intention to enhance image contrast through the analysis of scattering and diffraction signatures. A gold-on-TPX test structure and an archived biomedical tissue sample are examined in conventional and dark-field transmission geometry. In particular, the capability of the technique for tumor detection is addressed.

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

    NASA Astrophysics Data System (ADS)

    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. Effect of rare earth Ce on the far infrared radiation property of iron ore tailings ceramics

    SciTech Connect

    Liu, Jie; Meng, Junping; Liang, Jinsheng; Duan, Xinhui; Huo, Xiaoli; Tang, Qingguo

    2015-06-15

    Highlights: • Detailed process proposed for preparation of iron ore tailings ceramics. • Replace natural minerals with iron ore tailings as raw materials for preparing functional ceramics. • Impact mechanism of Ce on far infrared ceramics, as well as its optimum addition amounts can be obtained. • Propose a new perspective on considering the mechanism of far infrared radiation. - Abstract: A kind of far infrared radiation ceramics was prepared by using iron ore tailings, CaCO{sub 3} and SiO{sub 2} as main raw materials, and Ce as additive. The result of Fourier transform infrared spectroscopy showed that the sample exhibits excellent radiation value of 0.914 when doping 7 wt.% Ce. Ce{sup 4+} dissolved into iron diopside and formed interstitial solid solution with it sintered at 1150 °C. The oxidation of Fe{sup 2+} to Fe{sup 3+} caused by Ce{sup 4+} led to a decrease of crystallite sizes and enhancement of Mg–O and Fe–O vibration in iron diopside, which consequently improved the far infrared radiation properties of iron ore tailings ceramics.

  16. Multicolour far infrared photometry of galactic H2 regions. [data acquisition using high altitude balloons

    NASA Technical Reports Server (NTRS)

    Olthof, H.

    1974-01-01

    Results are presented of far infrared photometric measurements of H2 regions in the galactic plane between longitudes 350 and 40 degrees. The results are combined from balloon flights in 1972 and 1973 carried out in cooperation with CNES in the south of France.

  17. Infrared and far-infrared transition frequencies for the CH2 radical. [in interstellar gas clouds

    NASA Technical Reports Server (NTRS)

    Sears, T. J.; Mckellar, A. R. W.; Bunker, P. R.; Evenson, K. M.; Brown, J. M.

    1984-01-01

    A list of frequencies and intensities for transitions of CH2 in the middle and far infrared regions is presented which should aid in the detection of CH2 and provide valuable information on the local physical and chemical environment. Results are presented for frequency, vacuum wavelength, and line strength for rotational transition frequencies and for the transition frequencies of the v(2) band.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Design of high-T[sub c] superconducting bolometers for a far infrared imaging array

    SciTech Connect

    Verghese, S.; Richards, P.L. ); Fork, D.K. ); Char, K. ); Geballe, T.H. . Dept. of Applied Physics)

    1992-08-01

    The design of high-[Tc] superconducting bolometers for use in a far infrared imaging array from wavelengths 30--100[mu]m is discussed. Measurements of the voltage noise in thin films of YBa[sub 2]CU[sub 3]O[sub 7-[var sigma

  20. Charting the Winds that Change the Universe, II The Single Aperture Far Infrared Observatory (SAFIR)

    NASA Technical Reports Server (NTRS)

    Leisawitz, David

    2003-01-01

    The Single Aperture Far Infrared Observatory (SAFIR) will study the birth and evolution of stars and planetary systems so young that they are invisible to optical and near-infrared telescopes such as NGST. Not only does the far-infrared radiation penetrate the obscuring dust clouds that surround these systems, but the protoplanetary disks also emit much of their radiation in the far infrared. Furthermore, the dust reprocesses much of the optical emission from the newly forming stars into this wavelength band. Similarly, the obscured central regions of galaxies, which harbor massive black holes and huge bursts of star formation, can be seen and analyzed in the far infrared. SAFIR will have the sensitivity to see the first dusty galaxies in the universe. For studies of both star-forming regions in our galaxy and dusty galaxies at high redshifts, SAFIR will be essential in tying together information that NGST will obtain on these systems at shorter wavelengths and that ALMA will obtain at longer wavelengths.

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

    SciTech Connect

    Gutiérrez, W.; García, L. F.; Mikhailov, I. D.

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    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 measure of the total dust mass. The ratio of far-infrared to sub-millimetre flux is found to be greater for targets with discs that are brighter at millimetre wavelengths and that have steeper sub-millimetre slopes. Furthermore, discs with flared geometry have, on average, larger excesses than flat geometry discs. Finally, we estimate the extents of these discs (or provide upper limits) from the observations. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  3. CNES detector developments from far-infrared to mm: status and roadmap

    NASA Astrophysics Data System (ADS)

    Geoffray, H.; Monfardini, A.; Marnieros, S.; Piat, M.; Rodriguez, L.; Bardoux, A.

    2014-07-01

    CNES (French Space Agency) continuously drives the development of detectors for Space based Astronomy. Several detector concepts are developped by French Laboratories, from far infrared to mm wavelength. This paper gives a status on these developments as well as an overview of the associated roadmap.

  4. Determination of atmospheric temperature, water vapor, and heating rates from mid- and far- infrared hyperspectral measurements

    NASA Astrophysics Data System (ADS)

    Feldman, D.; Liou, K.; Yung, Y.; Johnson, D.; Mlynczak, M.

    2007-12-01

    Comprehensive satellite-borne far-infrared (15-100 μm) hyperspectral measurements of the earth have not been implemented since the short-lived Infrared Interferometer Sounder-D (IRIS-D) instrument on the Nimbus-4 satellite ceased operation in 1971 due primarily to instrumentation limitations and mission cost considerations. Recently, the development of the Far Infrared Spectroscopy of the Troposphere (FIRST) instrument [Mlynczak et al, 2006], a balloon-borne FTS which records spectra from 5 to 200 μm, provides a test-bed for the development of space-based far-infrared measurements for climate change monitoring. A comparison of the retrieval capabilities of a notional space-based instrument of comparable performance to FIRST and the currently-operational mid-infrared instrument AIRS is presented. Temperature and water vapor retrievals are compared (in an orbital simulation framework) along with the relative ability of the retrievals from these two instruments to constrain the heating rate profile. Also, the skill with which the AIRS measurements can be used to extrapolate the cloud radiative effect into the far-infrared is explored. Finally, FIRST test flight spectra are presented in the framework of other A-Train measurements such as MODIS and CALIPSO, followed by a discussion of climate applications.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  7. Interacting diffusive unified dark energy and dark matter from scalar fields

    NASA Astrophysics Data System (ADS)

    Benisty, David; Guendelman, E. I.

    2017-06-01

    Here we generalize ideas of unified dark matter-dark energy in the context of two measure theories and of dynamical space time theories. In two measure theories one uses metric independent volume elements and this allows one to construct unified dark matter-dark energy, where the cosmological constant appears as an integration constant associated with the equation of motion of the measure fields. The dynamical space-time theories generalize the two measure theories by introducing a vector field whose equation of motion guarantees the conservation of a certain Energy Momentum tensor, which may be related, but in general is not the same as the gravitational Energy Momentum tensor. We propose two formulations of this idea: (I) by demanding that this vector field be the gradient of a scalar, (II) by considering the dynamical space field appearing in another part of the action. Then the dynamical space time theory becomes a theory of Diffusive Unified dark energy and dark matter. These generalizations produce non-conserved energy momentum tensors instead of conserved energy momentum tensors which leads at the end to a formulation of interacting DE-DM dust models in the form of a diffusive type interacting Unified dark energy and dark matter scenario. We solved analytically the theories for perturbative solution and asymptotic solution, and we show that the Λ CDM is a fixed point of these theories at large times. Also a preliminary argument as regards the good behavior of the theory at the quantum level is proposed for both theories.

  8. Observations of CO isotopic emission and the far-infrared continuum of Centaurus A

    NASA Technical Reports Server (NTRS)

    Eckart, A.; Cameron, M.; Rothermel, H.; Wild, W.; Zinnecker, H.; Olberg, M.; Rydbeck, G.; Wiklind, T.

    1990-01-01

    Researchers present maps of the CO-12(1=0) line and the 100 micron and 50 micron far-infrared emission of Centaurus A, as well as measurements of the CO-12(2-1), CO-13(1-0), and the C-18O(1-0) lines at selected positions. The observations were taken with the Swedish-ESO Submillimeter Telescope (SEST) and the CPC instrument on board the Infrared Astronomy Satellite (IRAS). The millimeter data show that the bulk molecular material is closely associated with the dust lane and contained in a disk of about 180 seconds diameter and a total molecular mass of about 2 x 10 to the 8th power solar mass. The total molecular mass of the disk and bulge is of the order of 3 x 10 to the 8th power solar mass. The molecular gas in the nucleus is warm with a kinetic temperature of the order of 15 K and a number density of 10 to the 3rd power to 3 x 10 to the 4th power cm(-3). Absorption features in the CO-12 and CO-13 lines against the nuclear continuum emission indicate that the properties of giant molecular clouds are comparable to those of the Galaxy. The far-infrared data show that to a good approximation the dust temperature is constant across the dust lane at a value of about 42 K. The ratio between the far-infrared luminosity and the total molecular mass is 18 solar luminosity/solar mass and close to the mean value obtained for isolated galaxies. A comparison of the CO-12(1-0) and the far-infrared data indicates that a considerable amount of the far-infrared emission is not intimately associated with massive star formation.

  9. A microbolometer-based far infrared radiometer to study thin ice clouds in the Arctic

    NASA Astrophysics Data System (ADS)

    Libois, Quentin; Proulx, Christian; Ivanescu, Liviu; Coursol, Laurence; Pelletier, Ludovick S.; Bouzid, Yacine; Barbero, Francesco; Girard, Éric; Blanchet, Jean-Pierre

    2016-04-01

    A far infrared radiometer (FIRR) dedicated to measuring radiation emitted by clear and cloudy atmospheres was developed in the framework of the Thin Ice Clouds in Far InfraRed Experiment (TICFIRE) technology demonstration satellite project. The FIRR detector is an array of 80 × 60 uncooled microbolometers coated with gold black to enhance the absorptivity and responsivity. A filter wheel is used to select atmospheric radiation in nine spectral bands ranging from 8 to 50 µm. Calibrated radiances are obtained using two well-calibrated blackbodies. Images are acquired at a frame rate of 120 Hz, and temporally averaged to reduce electronic noise. A complete measurement sequence takes about 120 s. With a field of view of 6°, the FIRR is not intended to be an imager. Hence spatial average is computed over 193 illuminated pixels to increase the signal-to-noise ratio and consequently the detector resolution. This results in an improvement by a factor of 5 compared to individual pixel measurements. Another threefold increase in resolution is obtained using 193 non-illuminated pixels to remove correlated electronic noise, leading an overall resolution of approximately 0.015 W m-2 sr-1. Laboratory measurements performed on well-known targets suggest an absolute accuracy close to 0.02 W m-2 sr-1, which ensures atmospheric radiance is retrieved with an accuracy better than 1 %. Preliminary in situ experiments performed from the ground in winter and in summer on clear and cloudy atmospheres are compared to radiative transfer simulations. They point out the FIRR ability to detect clouds and changes in relative humidity of a few percent in various atmospheric conditions, paving the way for the development of new algorithms dedicated to ice cloud characterization and water vapor retrieval.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Far-Infrared and Optical Studies of Gallium Arsenide and Aluminum Gallium Arsenide Semiconductor Structures

    NASA Astrophysics Data System (ADS)

    Stanaway, Mark Brian

    Available from UMI in association with The British Library. Requires signed TDF. This thesis reports far-infrared (FIR) and photoluminescence studies, performed at low temperatures (4.2K) and at magnetic fields up to 25T, of selectively and inadvertently doped bulk and low dimensional gallium arsenide (GaAs) and aluminium gallium arsenide (AlGaAs) semiconductor structures grown by molecular beam epitaxy. High-resolution FIR magnetospectroscopy of ultra -high mobility n-GaAs reveals a variety of shallow donor intra-impurity transitions plus spin-split higher Landau level transitions in the photoconductive response. The first observation of polarons bound to D^ - ions in bulk n-GaAs is reported. The excited state spectrum of the confined silicon donor in GaAs/AlGaAs multi-quantum wells (MQWs) has been examined. Narrower linewidths and more higher excited state donor transitions are noted in the present photoconductive investigation compared with previous reports. The electron recombination dynamics has been examined in silicon-doped GaAs/AlGaAs MQWs and homogeneous and sheet -doped bulk n-GaAs samples using time-resolved FIR photoconductivity. The extrinsic response of doped MQW structures suggests a potential use as a fast, sensitive detectors of FIR. FIR transmission measurements are reported for GaAs/AlGaAs quantum wells (QWs) of various widths in magnetic fields of up to 20T, tilted away from the normal to the QW plane by angles up to theta = 50^circ. Deviation of the cyclotron resonance field from a costheta law are interpreted using theoretical models describing Landau level/electric subband coupling. The in-plane magnetic field and excitation power dependence of the photoluminescence intensity of a GaAs/AlGaAs QW spectral feature is interpreted in terms of charge transfer in the QW, using a coupled oscillator model, and the efficiency of nonradiative electronic traps. In-plane magnetic field studies of the photoluminescence from a superlattice structure

  12. Far-infrared electroluminescence characteristics of an InGaP/InGaAs/Ge triple-junction solar cell under forward DC bias

    NASA Astrophysics Data System (ADS)

    Wenbo, Xiao; Xingdao, He; Yiqing, Gao; Zhimin, Zhang; Jiangtao, Liu

    2012-06-01

    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.

  13. Dynamical dispersion relation for ELKO dark spinor fields

    NASA Astrophysics Data System (ADS)

    Bernardini, A. E.; da Rocha, Roldão

    2012-10-01

    An intrinsic mass generation mechanism for exotic ELKO dark matter fields is scrutinized, in the context of the very special relativity (VSR). Our results are reported on unraveling inequivalent spin structures that educe an additional term on the associated Dirac operator. Contrary to the spinor fields of mass dimension 3/2, this term is precluded to be absorbed as a shift of some gauge vector potential, regarding the equations for the dark spinor fields. It leads to some dynamical constraints that can be intrinsically converted into a dark spinor mass generation mechanism, with the encoded symmetries maintained by the VSR. The dynamical mass is embedded in the VSR framework through a natural coupling to the kink solution of a λϕ4 theory for a scalar field ϕ. Our results evince the possibility of novel effective scenarios, derived from exotic couplings among dark spinor fields and scalar field topological solutions.

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

    PubMed

    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.

  15. A far-infrared radiometer to study optically thin ice clouds in the Arctic

    NASA Astrophysics Data System (ADS)

    Libois, Q.; Ivanescu, L.; Blanchet, J. P.; Barbero, F.; Laurence, C.; Pelletier, L. S.; Proulx, C.; Dejmek, M.

    2015-12-01

    The water cycle in the dry and cold Arctic is not well understood. In particular, ice clouds, which play a significant role in the radiative budget of this region, are poorly known. In addition to filling a gap in cloud observation at high latitudes, the deployment of CALIPSO and CloudSat satellites also highlighted the ubiquity of optically thin ice clouds during the polar night in the Arctic. These clouds can significantly alter the amount of far infrared radiation escaping the Earth, and consequently the temperatures in the upper atmosphere. Since their signature in the far infrared is also very sensitive to their microphysical properties (crystals size and shape) and optical depth, these quantities can be retrieved from satellite observations. Such measurements in the far infrared (particularly beyond 30 μm), were until recently constrained by technical limitations, but recent advancements in micro-bolometers technology at INO (Québec) has allowed to study this under-explored spectral region. In this context, a satellite mission dedicated to studying thin ice clouds in the Arctic (TICFIRE) is under review at the Canadian Space Agency. We present here the Far InfraRed Radiometer (FIRR), which is meant to be a breadboard for the future satellite instrument. The FIRR measures atmospheric radiation in 9 spectral bands extending from 8 to 50 μm. After characterization in the laboratory, it was operated from the ground under various atmospheric conditions. These measurements were successfully compared to radiative transfer simulations, pointing out the potential of the FIRR to detect ice clouds and to measure low water vapor contents. In April 2015, the FIRR was operated on board an aircraft during the pan-arctic NETCARE campaign. It was looking downward to mimic satellite observations, which is to our knowledge a first in the far infrared. Simultaneously, atmospheric profiles and clouds microphysical properties were measured by probes mounted on the same aircraft

  16. Dark-field illuminated reflectance fiber bundle endoscopic microscope

    NASA Astrophysics Data System (ADS)

    Liu, Xuan; Huang, Yong; Kang, Jin U.

    2011-04-01

    We propose a reflectance fiber bundle microscope using a dark-field illumination configuration for applications in endoscopic medical imaging and diagnostics. Our experiment results show that dark-field illumination can effectively suppress strong specular reflection from the proximal end of the fiber bundle. We realized a lateral resolution of 4.4 μm using the dark-field illuminated fiber bundle configuration. To demonstrate the feasibility of using the system to study cell morphology, we obtained still and video images of two thyroid cancer cell lines. Our results clearly allow differentiation of different cancer cell types.

  17. Far Infrared Photoconductivity Studies in Mercury Cadmium-Telluride Superlattices and

    NASA Astrophysics Data System (ADS)

    Boero, Francis Joseph

    The advent of the molecular gas far-infrared (FIR) laser in 1972 has provided a monochromatic source in the heretofore inaccessible spectral region of 70-1500 (mu)m. When this source was integrated with a liquid Helium dewar and superconducting magnet the resulting instrument was ideally suited to magneto-optical studies of low energy electronic structures. The capabilities of the new spectrometer were directed towards newly developed one and two dimensional materials. A FIR laser optically pumped by a CO(,2) laser was constructed to cover the range 100-1000 (mu)m (10-100 cm('-1)). Special attention was given to selection of a minimal set of molecular gasses to cover this range as well as the development of an oversize waveguide system to transmit the energy into the experimental dewar. The development process included the design and optimization of reference bolometry for use at high magnetic fields. A superlattice composed of laser deposited HgTe and CdTe (layer thicknesses 110/200 Angstroms) was studied and found to exhibit a photoconductive resonance at 19 cm('-1) at 1.6 K. The lineshape and resonance strength were magnetic field dependent with the effect vanishing at 2.6 Tesla. The resonance was attributed to an energy level resonant with the bottom of the superlattice conduction band. By correlating S d-H measurements with photoconductive data the resonant level was placed 16 cm('-1) above the chemical potential. Extensive photoconductive measurements in the temperature range 1.7-3.2 K were made on the 1-dimensional organic superconductor (TMTSF)(,2)PF(,6). Photoconductivity variations with temperature, T, and magnetic field, B, were obtained at ambient pressure. The spin-density-wave gap determined optically was found to be 23 cm('-1) inconsistent with a measured thermal gap of 18 cm('-1). Photoconductive lineshapes were consistent with a 1-dimensional density of states. Both lineshape and gap discrepancy could be reconciled with a quasi 2-dimensional band

  18. Vector field models of modified gravity and the dark sector

    SciTech Connect

    Zuntz, J.; Ferreira, P. G.; Zlosnik, T. G; Bourliot, F.; Starkman, G. D.

    2010-05-15

    We present a comprehensive investigation of cosmological constraints on the class of vector field formulations of modified gravity called generalized Einstein-aether models. Using linear perturbation theory we generate cosmic microwave background and large-scale structure spectra for general parameters of the theory, and then constrain them in various ways. We investigate two parameter regimes: a dark matter candidate where the vector field sources structure formation, and a dark energy candidate where it causes late-time acceleration. We find that the dark matter candidate does not fit the data, and identify five physical problems that can restrict this and other theories of dark matter. The dark energy candidate does fit the data, and we constrain its fundamental parameters; most notably we find that the theory's kinetic index parameter n{sub ae} can differ significantly from its {Lambda}CDM value.

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

    PubMed

    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.

  20. Architecture and performance of the space-based Far-Infrared Interferometer Instrument Simulator

    NASA Astrophysics Data System (ADS)

    Juanola-Parramon, R.; Fenech, D. M.; Savini, G.

    2016-04-01

    FIRI (Far Infra-Red Interferometer) is a spatial and spectral space interferometer with an operating wavelength range of 25-400 μm and sub-arcsecond angular resolution. It is based on the combination of stellar interferometry and Fourier transform spectroscopy to perform spectroscopy at high angular resolution in the far-infrared. The resulting technique is referred to as double Fourier spatio-spectral interferometry. With increased spatial and spectral resolution come a number of interesting science cases such as the formation and evolution of AGN and the characterization of gas, ice and dust in discs undergoing planetary formation, among others. To study the feasibility of a FIRI system, the Far-Infrared Interferometer Instrument Simulator (FIInS) has been developed. With FIInS, once a set of modelled scientific data is available, one can compare an input sky map with the synthesized one after data reduction algorithms have been applied.

  1. Conceptual thermal design and analysis of a far-infrared/mid-infrared remote sensing instrument

    NASA Technical Reports Server (NTRS)

    Roettker, William A.

    1992-01-01

    This paper presents the conceptual thermal design and analysis results for the Spectroscopy of the Atmosphere using Far-Infrared Emission (SAFIRE) instrument. SAFIRE has been proposed for Mission to Planet Earth to study ozone chemistry in the middle atmosphere using remote sensing of the atmosphere in the far-infrared (21-87 microns) and mid-infrared (9-16 microns) spectra. SAFIRE requires that far-IR detectors be cooled to 3-4 K and mid-IR detectors to 80 K for the expected mission lifetime of five years. A superfluid helium dewar and Stirling-cycle cryocoolers provide the cryogenic temperatures required by the infrared detectors. The proposed instrument thermal design uses passive thermal control techniques to reject 465 watts of waste heat from the instrument.

  2. Collision-induced absorption in the far infrared spectrum of Titan

    NASA Technical Reports Server (NTRS)

    Hunt, J. L.; Poll, J. D.; Goorvitch, D.; Tipping, R. H.

    1983-01-01

    The effects of collision-induced absorption on the far infrared spectrum of Titan have been investigated. After a review of the procedure for the theoretical calculation of the N2 translation-rotational spectrum, new results for the temperature range o 70 to 120 K are reported. These are used as input data for a simple atmospheric model in order to compute the far infrared radiance, brightness temperature, and specral limb function. This source of opacity alone is not capable of explaining the Voyager results. When the collision-induced methane is included, the results are in closer agreement in the range between 200 and 300/cm, suggesting that a more complete treatment of collision-induced absorption including particularly CH4-N2, N2-H2, and H2-H2 results, may provide sufficient opacity to reduce or obviate the need for opacities due to clouds or aerosols in order to explain the observed spectra.

  3. Far-infrared line observations of planetary nebulae. 1: The O 3 spectrum

    NASA Technical Reports Server (NTRS)

    Dinerstein, H. L.; Lester, D. F.; Werner, M. W.

    1985-01-01

    Observations of the far-infrared fine structure lines of O III have been obtained for six planetary nebulae. The infrared measurements are combined with optical O III line fluxes to probe physical conditions in the gas. From the observed line intensity ratios, a simultaneous solution was obtained for electron temperature and density, as well as means of evaluating the importance of inhomogeneities. Densities determined from the far-infrared O III lines agree well density diagnostics from other ions, indicating a fairly homogeneous density in the emitting gas. Temperatures are determined separately from the O III 4363/5007 A and 5007 A/52 micron intensity ratios and compared. Systematically higher values are derived from the former ratio, which is expected from a nebula which is not isothermal. Allowance for the presence of temperature variations within these nebulae raises their derived oxygen abundances, determinations to be reconciled with the solar value.

  4. Far-Infrared [CII] Line Observation of the Galactic Plane by IRTS

    NASA Astrophysics Data System (ADS)

    Makiuti, Sin'itirou; Shibai, Hiroshi; Okuda, Haruyuki; Nakagawa, Takao; Matsuhara, Hideo; Hiromoto, Norihisa; Okumura, Ken'ichi

    1996-10-01

    A detailed map of the distribution of the [CII] 158 mu m line intensity from the galactic plane around l = 50(deg) was obtained by the Far-Infrared Line Mapper (FILM) on board the Infrared Telescope in Space (IRTS). The distribution of the [CII] emission is similar to that of the far-infrared continuum emission. There are a number of discrete sources, most of which correspond to known objects, such as compact HII regions and molecular clouds, near to the galactic plane. Moreover, an extended component concentrated in the galactic plane was found, and its distribution does not clearly depend on the galactic longitude in the observed area. This extended component decreases rapidly as the galactic latitude increases. The FWHM of this component is about 2.(deg) 6 in the galactic latitude. This is larger than that of the CO (J=1 -> 0) intensity, but is much smaller than that of the HI 21 cm intensity.

  5. New far infrared images of bright, nearby, star-forming regions

    NASA Technical Reports Server (NTRS)

    Harper, D. AL, Jr.; Cole, David M.; Dowell, C. Darren; Lees, Joanna F.; Lowenstein, Robert F.

    1995-01-01

    Broadband imaging in the far infrared is a vital tool for understanding how young stars form, evolve, and interact with their environment. As the sensitivity and size of detector arrays has increased, a richer and more detailed picture has emerged of the nearest and brightest regions of active star formation. We present data on M 17, M 42, and S 106 taken recently on the Kuiper Airborne Observatory with the Yerkes Observatory 60-channel far infrared camera, which has pixel sizes of 17 in. at 60 microns, 27 in. at 100 microns, and 45 in. at 160 and 200 microns. In addition to providing a clearer view of the complex central cores of the regions, the images reveal new details of the structure and heating of ionization fronts and photodissociation zones where radiation form luminous stars interacts with adjacent molecular clouds.

  6. Investigations of Ge-Te-AgI chalcogenide glass for far-infrared application.

    PubMed

    Wang, Xunsi; Nie, Qiuhua; Wang, Guoxiang; Sun, Jie; Song, Baoan; Dai, Shixun; Zhang, Xianghua; Bureau, Bruno; Boussard, Catherine; Conseil, Clément; Ma, Hongli

    2012-02-01

    A serious of tellurium based chalcogenide glass were prepared and investigated. As it being transparent nearly up to 25 μm and strong anti-hydrability, it becomes an optimized material for far-infrared application. Here, AgI was incorporated into the glasses acting as a glass modifier. With the help of AgI, a highest glass transition temperature, T(g) (151 °C) can be obtained. Detailed physics and chemic properties of the glasses were analyzed with DTA and XRD. The infrared optical transmission spectra were studied with the help of FTIR and Raman test. A purifying process was adopted to eliminate the affections of impurities in the tellurium glass. These serious of glasses are all high transparent in the 8-20 μm region, which fits for the applications of far-infrared optic imaging and sensing. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Simultaneous far-infrared, near-infrared, and radio observations of OH/IR stars

    NASA Technical Reports Server (NTRS)

    Werner, M. W.; Beckwith, S.; Gatley, I.; Sellgren, K.; Whiting, D. L.; Berriman, G.

    1980-01-01

    Simultaneous far-infrared, near-infrared, and radio observations have been made of five infrared stars which show OH maser emission at 1612 MHz. These stars have very thick circumstellar dust shells and are not seen optically. The data permit a direct comparison of the far-infrared and maser emission from these sources, which strongly supports the hypothesis that the maser emission is pumped by 35 micron photons. A comparison with data obtained at earlier epochs suggests that the maser emission is saturated. The infrared and radio data are used together with estimates of the source distances to determine the luminosities and mass loss rates for these objects. The luminosities lie in the range 2000-30,000 solar luminosities and are consistent with either Mira variable or M supergiant classifications for the underlying stars. The estimated mass loss rates lie between 0.000005-0.00007 solar mass/year.

  8. New far infrared images of bright, nearby, star-forming regions

    NASA Technical Reports Server (NTRS)

    Harper, D. AL, Jr.; Cole, David M.; Dowell, C. Darren; Lees, Joanna F.; Lowenstein, Robert F.

    1995-01-01

    Broadband imaging in the far infrared is a vital tool for understanding how young stars form, evolve, and interact with their environment. As the sensitivity and size of detector arrays has increased, a richer and more detailed picture has emerged of the nearest and brightest regions of active star formation. We present data on M 17, M 42, and S 106 taken recently on the Kuiper Airborne Observatory with the Yerkes Observatory 60-channel far infrared camera, which has pixel sizes of 17 in. at 60 microns, 27 in. at 100 microns, and 45 in. at 160 and 200 microns. In addition to providing a clearer view of the complex central cores of the regions, the images reveal new details of the structure and heating of ionization fronts and photodissociation zones where radiation form luminous stars interacts with adjacent molecular clouds.

  9. Far-infrared spectroscopy of NGC 6946, IC 342, and Arp 299

    NASA Technical Reports Server (NTRS)

    Lord, Steven D.; Hollenbach, David J.; Colgan, Sean W. J.; Haas, Michael R.; Rubin, Robert H.; Erickson, Edwin F.

    1990-01-01

    Researchers investigated the physical conditions in the infrared bright galaxies NGC 6946, IC 342, and Arp 299 through measurements of far-infrared emission lines from Si II, O I, C II, and O III using the facility Cooled Grating Spectrometer on the Kuiper Airborne Observatory. These data are interpreted using our theoretical models for photodissociation regions and H II regions. For the central 45 inches of these galaxies, researchers determined that the dominant excitation mechanism for the far infrared radiation (FIR) lines is far ultraviolet radiation (FUR) radiation from young stars, and the authors derived the total mass, density, and temperature of the warm atomic gas and the typical sizes, number densities, and filling factors for the interstellar clouds.

  10. Helium-cooled Michelson interferometer for far-infrared astronomy aboard German Infrared Laboratory /GIRL/

    NASA Astrophysics Data System (ADS)

    Drapatz, S.; Hofmann, R.; Katterloher, R.

    1981-01-01

    It is pointed out that high-resolution spectroscopy in the mid and far-infrared region is potentially of great importance for the study of astronomical objects. This importance is partly related to the location of the atomic and ionic emission lines of abundant elements in the considered region. In addition, this spectral region contains also the vibration and rotational line spectra of important molecules. In order to take advantage of the envisaged potential, a He-cooled Michelson interferometer is being developed for the German Infra-Red Laboratory (GIRL) which is to be flown on board of Spacelab in 1986. The considered instrument is the first He-cooled interferometer for high spectral resolution in the far-infrared region. Attention is given to the design of the experiment, its construction, the development status and future aspects.

  11. Conceptual thermal design and analysis of a far-infrared/mid-infrared remote sensing instrument

    NASA Technical Reports Server (NTRS)

    Roettker, William A.

    1992-01-01

    This paper presents the conceptual thermal design and analysis results for the Spectroscopy of the Atmosphere using Far-Infrared Emission (SAFIRE) instrument. SAFIRE has been proposed for Mission to Planet Earth to study ozone chemistry in the middle atmosphere using remote sensing of the atmosphere in the far-infrared (21-87 microns) and mid-infrared (9-16 microns) spectra. SAFIRE requires that far-IR detectors be cooled to 3-4 K and mid-IR detectors to 80 K for the expected mission lifetime of five years. A superfluid helium dewar and Stirling-cycle cryocoolers provide the cryogenic temperatures required by the infrared detectors. The proposed instrument thermal design uses passive thermal control techniques to reject 465 watts of waste heat from the instrument.

  12. Far-infrared spectroscopy of CdTe1-xSex(In): Phonon properties

    NASA Astrophysics Data System (ADS)

    Petrović, M.; Romčević, N.; Trajić, J.; Dobrowolski, W. D.; Romčević, M.; Hadžić, B.; Gilić, M.; Mycielski, A.

    2014-11-01

    The far-infrared reflectivity spectra of CdTe0.97Se0.03 and CdTe0.97Se0.03(In) single crystals were measured at different temperatures. The analysis of the far-infrared spectra was carried out by a fitting procedure based on the dielectric function which includes spatial distribution of free carriers as well as their influence on the plasmon-phonon interaction. We found that the long wavelength optical phonon modes of CdTe1-xSex mixed crystals exhibit a two-mode behavior. The local In mode at about 160 cm-1 is observed. In both sample, a surface layer with a low concentration of free carriers (depleted region) are formed.

  13. Negative refraction and self-collimation in the far infrared with aligned carbon nanotube films

    NASA Astrophysics Data System (ADS)

    Zhang, Richard Z.; Zhang, Zhuomin M.

    2015-06-01

    This study demonstrates the far-infrared self-collimation and low-loss transmission of aligned carbon nanotube (CNT) films or arrays. The anisotropic dielectric functions of the CNT array is modeled using the effective medium theory considering the degree of alignment. The spectral regions where hyperbolic dispersion is satisfied are in the far-infrared. In the hyperbolic regime, energy propagates inside the CNT film along the optical axis for nearly all incidence angles. The self-collimation effect is also examined for tilted CNT thin films by tracing the Poynting vector trajectories. Low-loss transmission is explored to understand the impact of alignment on the penetration depth and transmission through the film. In conjunction with the surface radiative properties, the self-collimation and transmission characteristics are distinguished between the two hyperbolic bands of the CNT film. The insight obtained from this work may lead to the utilization of CNT arrays in polarization filtering and infrared imaging.

  14. Far-infrared vibrational modes of DNA components studied by terahertz time-domain spectroscopy.

    PubMed

    Fischer, B M; Walther, M; Uhd Jepsen, P

    2002-11-07

    The far-infrared dielectric function of a wide range of organic molecules is dominated by vibrations involving a substantial fraction of the atoms forming the molecule and motion associated with intermolecular hydrogen bond vibrations. Due to their collective nature such modes are highly sensitive to the intra- and intermolecular structure and thus provide a unique fingerprint of the conformational state of the molecule and effects of its environment. We demonstrate the use of terahertz time-domain spectroscopy (THz-TDS) for recording the far-infrared (0.5-4.0 THz) dielectric function of the four nucleobases and corresponding nucleosides forming the building blocks of deoxyribose nucleic acid (DNA). We observe numerous distinct spectral features with large differences between the molecules in both frequency-dependent absorption coefficient and index of refraction. Assisted by results from density-functional calculations we interpret the origin of the observed resonances as vibrations of hydrogen bonds between the molecules.

  15. Far-infrared contraband-detection-system development for personnel-search applications

    SciTech Connect

    Schellenbaum, R. L.

    1982-09-01

    Experiments have been conducted toward the development of an active near-millimeter-wave, far infrared, personnel search system for the detection of contraband. These experiments employed a microwave hybrid tee interferometer/radiometer scanning system and quasi-optical techniques at 3.3-mm wavelength to illuminate and detect the reflection from target objects against a human body background. Clothing and other common concealing materials are transport at this wavelength. Retroreflector arrays, in conjunction with a Gunn diode radiation source, were investigated to provide all-angle illumination and detection of specular reflections from unaligned and irregular-shaped objects. Results indicate that, under highly controlled search conditions, metal objects greater than or equal to 25 cm/sup 2/ can be detected in an enclosure lined with retroreflectors. Further development is required to produce a practical personnel search system. The investigation and feasibility of alternate far infrared search techniques are presented. 23 figures, 2 tables.

  16. A high resolution far-infrared survey of a section of the galactic plane. I - The nature of the sources

    NASA Technical Reports Server (NTRS)

    Jaffe, D. T.; Stier, M. T.; Fazio, G. G.

    1982-01-01

    Far-infrared, radio continuum and (C-12)O and (C-13)O line observations are presented of 42 far-infrared sources. The sources range in luminosity from 4000 to 3,000,000 solar luminosities. Most of them are associated with (C-12)O peaks. More than half the sources have associated H2O maser emission, and half possess associated radio continuum emission at a limit of 100 mJy. Eight have radio emission at weaker levels. In many cases, the far-infrared source is smaller than its associated radio source. The difference can be explained in the context of the 'blister' picture of H II regions. One group of sources emits many fewer Lyman continuum photons than expected, considering the far-infrared luminosities. A number of possible reasons for this are examined; the explanation holding that clusters of early type stars rather than single stars excite the far-infrared sources is considered the most reasonable.

  17. A high resolution far-infrared survey of a section of the galactic plane. I - The nature of the sources

    NASA Technical Reports Server (NTRS)

    Jaffe, D. T.; Stier, M. T.; Fazio, G. G.

    1982-01-01

    Far-infrared, radio continuum and (C-12)O and (C-13)O line observations are presented of 42 far-infrared sources. The sources range in luminosity from 4000 to 3,000,000 solar luminosities. Most of them are associated with (C-12)O peaks. More than half the sources have associated H2O maser emission, and half possess associated radio continuum emission at a limit of 100 mJy. Eight have radio emission at weaker levels. In many cases, the far-infrared source is smaller than its associated radio source. The difference can be explained in the context of the 'blister' picture of H II regions. One group of sources emits many fewer Lyman continuum photons than expected, considering the far-infrared luminosities. A number of possible reasons for this are examined; the explanation holding that clusters of early type stars rather than single stars excite the far-infrared sources is considered the most reasonable.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  20. Development of far infrared attenuation to measure electron densities in cw pin discharge lasers

    NASA Technical Reports Server (NTRS)

    Babcock, R. V.

    1977-01-01

    A two beam attenuation technique was devised to measure electron densities 10 to the 9th power to 10 to the 11th power cm/3 resolved to 1 cm, in a near atmospheric COFFEE laser discharge, using 496 micrometer and 1,220 micrometer radiations from CH3F, optically pumped by a CO2 laser. A far infrared generator was developed which was suitable except for a periodic intensity variation in FIR output deriving from frequency variation of the pump radiation.

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

    NASA Technical Reports Server (NTRS)

    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. Plans for a far-infrared free-electron laser in India

    SciTech Connect

    Krishnagopal, S.; Kumar, V.; Ramamurthi, S.S.

    1995-12-31

    The Centre for Advanced Technology is building the INDUS complex of synchrotron radiation sources. As part of this programme it is also proposed to build a far-infrared free-electron laser oscillator. This will use a microtron injector and a 40 period undulator made of NdFeB permanent magnets, and is designed to law around 200 microns. We discuss details of the FEL design and the present status of experimental activities on this front.

  3. A new software tool for computing Earth's atmospheric transmission of near- and far-infrared radiation

    NASA Technical Reports Server (NTRS)

    Lord, Steven D.

    1992-01-01

    This report describes a new software tool, ATRAN, which computes the transmittance of Earth's atmosphere at near- and far-infrared wavelengths. We compare the capabilities of this program with others currently available and demonstrate its utility for observational data calibration and reduction. The program employs current water-vapor and ozone models to produce fast and accurate transmittance spectra for wavelengths ranging from 0.8 microns to 10 mm.

  4. Negative index short-slab pair and continuous wires metamaterials in the far infrared regime.

    PubMed

    Gundogdu, T F; Katsarakis, N; Kafesaki, M; Penciu, R S; Konstantinidis, G; Kostopoulos, A; Economou, E N; Soukoulis, C M

    2008-06-09

    Using transmission and reflection measurements under normal incidence in one and three layers of a mum-scale metamaterial consisting of pairs of short-slabs and continuous wires, fabricated by a photolithography procedure, we demonstrate the occurrence of a negative refractive index regime in the far infrared range, ~2.4-3 THz. The negative index behavior in that system at ~2.4-3 THz is further confirmed by associated simulations, which are in qualitative agreement with the experimental results.

  5. A far-infrared spectral sequence of galaxies: trends and models

    SciTech Connect

    Fischer, Jacqueline; Abel, N. P.; González-Alfonso, E.; Dudley, C. C.; Satyapal, S.; Van Hoof, P. A. M.

    2014-11-10

    We present a framework for the interpretation of the far-infrared spectra of galaxies in which we have expanded the model parameters compared with previous work by varying the ionization parameter U, column density N(H), and gas density at the cloud face n(H{sup +}) for a central starburst or active galactic nucleus (AGN). We compare these models carried out with the Cloudy spectral synthesis code to trends in line-to-total far-infrared luminosity ratios, far-infrared fine-structure line ratios, IRAS colors, and OH and H{sub 2}O column densities found in the well-studied sample of 10 nearby galaxies from the IRAS Bright Galaxy Sample with infrared luminosities greater than 10{sup 10} L {sub ☉} and IRAS 60 μm fluxes equal to or greater than that of the nearby ultraluminous infrared galaxy (ULIRG) Arp 220. We find that the spectral sequence extending from normal starburst-type emission-line-dominated spectra to ULIRG-type absorption-dominated spectra with significant absorption from excited levels can be best explained by simultaneously increasing the hydrogen column density, from as low as 10{sup 21} cm{sup –2} to as high as 10{sup 24.8} cm{sup –2} or greater, and the ionization parameter, from as low as 10{sup –4} to as high as 1. The starburst models best reproduce most of the sequence, while AGN models are somewhat better able to produce the high OH and H{sub 2}O column densities in Arp 220. Our results suggest that the molecular interstellar medium in ULIRG-like, molecular-absorption-dominated systems is located close to and at least partially obscures the source of power throughout much of the far-infrared, which must be taken into account in order to properly interpret diagnostics of both their sources of power and of feedback.

  6. The Relationship Between Dynamics and Structure in the Far Infrared Absorption Spectrum of Liquid Water

    SciTech Connect

    Woods, K.

    2005-01-14

    Using an intense source of far-infrared radiation, the absorption spectrum of liquid water is measured at a temperature ranging from 269 to 323 K. In the infrared spectrum we observe modes that are related to the local structure of liquid water. Here we present a FIR measured spectrum that is sensitive to the low frequency (< 100cm{sup -1}) microscopic details that exist in liquid water.

  7. The Case for Space-Borne Far-Infrared Line Surveys

    NASA Technical Reports Server (NTRS)

    Bock, J. J.; Bradford, C. M.; Dragovan, M.; Earle, L.; Glenn, J.; Naylor, B.; Nguyen, H. T.; Zmuidzinas, J.

    2004-01-01

    The combination of sensitive direct detectors and a cooled aperture promises orders of magnitude improvement in the sensitivity and survey time for far-infrared and submillimeter spectroscopy compared to existing or planned capabilities. Continuing advances in direct detector technology enable spectroscopy that approaches the background limit available only from space at these wavelengths. Because the spectral confusion limit is significantly lower than the more familiar spatial confusion limit encountered in imaging applications, spectroscopy can be carried out to comparable depth with a significantly smaller aperture. We are developing a novel waveguide-coupled grating spectrometer that disperses radiation into a wide instantaneous bandwidth with moderate resolution (R 1000) in a compact 2-dimensional format. A line survey instrument coupled to a modest cooled single aperture provides an attractive scientific application for spectroscopy with direct detectors. Using a suite of waveguide spectrometers, we can obtain complete coverage over the entire far-infrared and sub-millimeter. This concept requires no moving parts to modulate the optical signal. Such an instrument would be able to conduct a far-infrared line survey 10 6 times faster than planned capabilities, assuming existing detector technology. However, if historical improvements in bolometer sensitivity continue, so that photon-limited sensitivity is obtained, the integration time can be further reduced by 2 to 4 orders of magnitude, depending on wavelength. The line flux sensitivity would be comparable to ALMA, but at shorter wavelengths and with the continuous coverage needed to extract line fluxes for sources at unknown redshifts. For example, this capability would break the current spectroscopic bottleneck in the study of far-infrared galaxies, the recently discovered, rapidly evolving objects abundant at cosmological distances.

  8. Far-Infrared Observations of Radio Quasars and FR II Radio Galaxies

    NASA Astrophysics Data System (ADS)

    Shi, Y.; Rieke, G. H.; Hines, D. C.; Neugebauer, G.; Blaylock, M.; Rigby, J.; Egami, E.; Gordon, K. D.; Alonso-Herrero, A.

    2005-08-01

    We report MIPS photometry of 20 radio-loud quasars and galaxies at 24 and 70 μm (and of five at 160 μm). We combine this sample with additional sources detected in the far-infrared by IRAS and ISO for a total of 47 objects, including 23 steep-spectrum type I AGNs: radio-loud quasars and broad-line radio galaxies; and 24 type II AGNs: narrow-line and weak-line FR II radio galaxies. Of this sample, the far-infrared emission of all but 3C 380 appears to be dominated by emission by dust heated by the AGN and by star formation. The AGN appears to contribute more than 50% of the far-infrared luminosity in most of the sources. It is also expected that the material around the nucleus is optically thin in the far-infrared. Thus, the measurements at these wavelengths can be used to test the orientation-dependent unification model. As predicted by the model, the behavior of the sources is consistent with the presence of an obscuring circumnuclear torus; in fact, we find that it may still have significant optical depth at 24 μm. In addition, as expected for the radio-loud quasars, there is a significant correlation between the low-frequency radio (178 MHz) and the 70 μm emission, two presumably isotropic indicators of nuclear activity. This result is consistent with the simple unified scheme. However, there is a population of radio galaxies that are underluminous at 70 μm compared with the radio-loud quasars and hence are a challenge to the simple unified model.

  9. Tunable far infrared studies of molecular parameters in support of stratospheric measurements

    NASA Technical Reports Server (NTRS)

    Chance, Kelly V.; Evenson, K. M.; Park, K.; Radostitz, J. V.; Jennings, D. A.; Nolt, I. G.; Vanek, M. D.

    1991-01-01

    Lab studies were made in support of far infrared spectroscopy of the stratosphere using the Tunable Far InfraRed (TuFIR) method of ultrahigh resolution spectroscopy and, more recently, spectroscopic and retrieval calculations performed in support of satellite-based atmospheric measurement programs: the Global Ozone Monitoring Experiment (GOME), and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY).

  10. Radio continuum and far-infrared emission of spiral galaxies: Implications of correlations

    NASA Technical Reports Server (NTRS)

    Rengarajan, T. N.; Iyengar, K. V. K.

    1990-01-01

    Researchers present a study extending the correlation seen between radio continuum and far-infrared emissions from spiral galaxies to a lower frequency of 408 MHz and also as a function of radio spectral index. The tight correlation seen between the two luminosities is then used to constrain several parameters governing the emissions such as the changes in star formation rate and mass function, frequency of supernovae that are parents of the interstellar electrons and factors governing synchrotron radio emission.

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    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 and (sub)-mm fluxes are available. We 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 spectral slopes between near- and far-infrared are mostly between -0.5 and -1.2 in our sample, which is comparable to more massive T Tauri stars; this may imply that the disk shapes are similar as well, although highly flared disks are rare among brown dwarfs. We find that dust temperatures in the range of 7-15 K, calculated with T ≈ 25 (L/L⊙)0.25 K, are appropriate for deriving disk masses from (sub)-mm fluxes for these low luminosity objects. About half of our sample hosts disks with at least one Jupiter mass, confirming that many brown dwarfs harbor sufficient material for the formation of Earth-mass planets in their midst. Herschel is a ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  12. Mode structure in an optically pumped D sub 2 O far-infrared ring laser

    SciTech Connect

    Yuan, D.C. ); Soumagne, G.; Siegrist, M.R. )

    1990-02-01

    The mode structures in an optically pumped D {sub 2} O far-infrared ring laser and a corresponding linear resonator are compared in this paper. While single-mode operation can be obtained over the whole useful pressure range in the ring structure, this is only possible at pressures greater than 8 torr in the linear resonator case. A numerical model predicts quite well the pulse shape, pressure dependence, and influence of the resonator quality in the ring cavity.

  13. Performances Of Arrays Of Ge:Ga Far-Infrared Detectors

    NASA Technical Reports Server (NTRS)

    Mccreight, C.; Farhoomand, J.

    1992-01-01

    Report presents evaluation of performances of two electronic modules containing few-element linear focal-plane arrays of Ge:Ga photodetectors and associated multiplexing readout circuitry. Tested to demonstrate feasibility of many-element, two-dimensional focal-plane arrays of far-infrared detectors and associated circuitry for use in astronomical and other low-background scientific observations. Revealed deficiencies that must be overcome in future designs.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Mode structure in an optically pumped D2O far-infrared ring laser

    NASA Astrophysics Data System (ADS)

    Yuan, D. C.; Soumagne, G.; Siegrist, M. R.

    1990-02-01

    The mode structures in an optically pumped D2O far-infrared ring laser and a corresponding linear resonator have been compared. While single-mode operation can be obtained over the whole useful pressure range in the ring structure, this is only possible at pressures greater than 8 torr in the linear resonator case. A numerical model predicts quite well the pulse shape, pressure dependence, and influence of the resonator quality in the ring cavity.

  16. Evidence that far-infrared radiation promotes growth of xenopus laevis

    NASA Astrophysics Data System (ADS)

    Shiurba, Robert; Hirabayashi, Tatsuo; Kiyokawa, Shin; Fukui, Akimasa; Miyanaga, Yuko; Kojima, Issey; Asashima, Makoto

    1999-01-01

    In most ectotherms, environmental temperature has differential effects on growth and differentiation. For example, amphibian size at maturity decreases with increasing temperature. To address how radiant heat in the form of far-infrared radiation (FIR) may affect development of the aquatic ectotherm Xenopus laevis, we continuously irradiated swimming larvae as they developed into young adults. Here we report evidence that FIR promotes growth of these organisms in an aqueous environment.

  17. A Herschel/PACS Far-infrared Line Emission Survey of Local Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Díaz-Santos, T.; Armus, L.; Charmandaris, V.; Lu, N.; Stierwalt, S.; Stacey, G.; Malhotra, S.; van der Werf, P. P.; Howell, J. H.; Privon, G. C.; Mazzarella, J. M.; Goldsmith, P. F.; Murphy, E. J.; Barcos-Muñoz, L.; Linden, S. T.; Inami, H.; Larson, K. L.; Evans, A. S.; Appleton, P.; Iwasawa, K.; Lord, S.; Sanders, D. B.; Surace, J. A.

    2017-09-01

    We present an analysis of {[{{O}}{{I}}]}63, [O iii]88, [N ii]122, and {[{{C}}{{II}}]}158 far-infrared (FIR) fine-structure line observations obtained with Herschel/PACS, for ∼240 local luminous infrared galaxies (LIRGs) in the Great Observatories All-sky LIRG Survey. We find pronounced declines (“deficits”) of line-to-FIR continuum emission for [N ii]122, {[{{O}}{{I}}]}63, and {[{{C}}{{II}}]}158 as a function of FIR color and infrared luminosity surface density, {{{Σ }}}{IR}. The median electron density of the ionized gas in LIRGs, based on the [N ii]122/[N ii]205 ratio, is {n}{{e}} = 41 cm‑3. We find that the dispersion in the {[{{C}}{{II}}]}158 deficit of LIRGs is attributed to a varying fractional contribution of photodissociation regions (PDRs) to the observed {[{{C}}{{II}}]}158 emission, f([{{C}} {{II}}{]}158{PDR}) = [{{C}} {{II}}{]}158{PDR}/{[{{C}}{{II}}]}158, which increases from ∼60% to ∼95% in the warmest LIRGs. The {[{{O}}{{I}}]}63/[{{C}} {{II}}{]}158{PDR} ratio is tightly correlated with the PDR gas kinetic temperature in sources where {[{{O}}{{I}}]}63 is not optically thick or self-absorbed. For each galaxy, we derive the average PDR hydrogen density, {n}{{H}}, and intensity of the interstellar radiation field, G, in units of {G}0 and find G/{n}{{H}} ratios of ∼0.1–50 {G}0 cm3, with ULIRGs populating the upper end of the distribution. There is a relation between G/{n}{{H}} and {{{Σ }}}{IR}, showing a critical break at {{{Σ }}}{IR}* ≃ 5 × 1010 L ⊙ kpc‑2. Below {{{Σ }}}{IR}* , G/{n}{{H}} remains constant, ≃0.32 {G}0 cm3, and variations in {{{Σ }}}{IR} are driven by the number density of star-forming regions within a galaxy, with no change in their PDR properties. Above {{{Σ }}}{IR}* , G/{n}{{H}} increases rapidly with {{{Σ }}}{IR}, signaling a departure from the typical PDR conditions found in normal star-forming galaxies toward more intense/harder radiation fields and compact geometries typical of starbursting sources.

  18. Simple Technique for Dark-Field Photography of Immunodiffusion Bands

    PubMed Central

    Jensh, Ronald P.; Brent, Robert L.

    1969-01-01

    A simple dark-field photographic technique was developed which enables laboratory personnel with minimal photographic training to easily record antigen-antibody patterns on immunodiffusion plates. Images PMID:4979944

  19. The Herschel Exploitation of Local Galaxy Andromeda (HELGA). I. Global far-infrared and sub-mm morphology

    NASA Astrophysics Data System (ADS)

    Fritz, J.; Gentile, G.; Smith, M. W. L.; Gear, W. K.; Braun, R.; Duval, J. Roman; Bendo, G. J.; Baes, M.; Eales, S. A.; Verstappen, J.; Blommaert, J. A. D. L.; Boquien, M.; Boselli, A.; Clements, D.; Cooray, A. R.; Cortese, L.; De Looze, I.; Ford, G. P.; Galliano, F.; Gomez, H. L.; Gordon, K. D.; Lebouteiller, V.; O'Halloran, B.; Kirk, J.; Madden, S. C.; Page, M. J.; Remy, A.; Roussel, H.; Spinoglio, L.; Thilker, D.; Vaccari, M.; Wilson, C. D.; Waelkens, C.

    2012-10-01

    Context. We have obtained Herschel images at five wavelengths from 100 to 500 μm of a ~5.5 × 2.5 degree area centred on the local galaxy M 31 (Andromeda), our nearest neighbour spiral galaxy, as part of the Herschel guaranteed time project "HELGA". The main goals of HELGA are to study the characteristics of the extended dust emission, focusing on larger scales than studied in previous observations of Andromeda at an increased spatial resolution, and the obscured star formation. Aims: In this paper we present data reduction and Herschel maps, and provide a description of the far-infrared morphology, comparing it with features seen at other wavelengths. Methods: We used high-resolution maps of the atomic hydrogen, fully covering our fields, to identify dust emission features that can be associated to M 31 with confidence, distinguishing them from emission coming from the foreground Galactic cirrus. Results: Thanks to the very large extension of our maps we detect, for the first time at far-infrared wavelengths, three arc-like structures extending out to ~21, ~26 and ~31 kpc respectively, in the south-western part of M 31. The presence of these features, hosting ~2.2 × 106 M⊙ of dust, is safely confirmed by their detection in HI maps. Overall, we estimate a total dust mass of ~5.8 × 107 M⊙, about 78% of which is contained in the two main ring-like structures at 10 and 15 kpc, at an average temperature of 16.5 K. We find that the gas-to-dust ratio declines exponentially as a function of the galacto-centric distance, in agreement with the known metallicity gradient, with values ranging from 66 in the nucleus to ~275 in the outermost region. Conclusions: Dust in M 31 extends significantly beyond its optical radius (~21 kpc) and what was previously mapped in the far-infrared. An annular-like segment, located approximately at R25, is clearly detected on both sides of the galaxy, and two other similar annular structures are undoubtedly detected on the south

  20. The Infrared Spectral Energy Distribution of Normal Star-forming Galaxies: Calibration at Far-Infrared and Submillimeter Wavelengths

    NASA Astrophysics Data System (ADS)

    Dale, Daniel A.; Helou, George

    2002-09-01

    New far-infrared and submillimeter data are used to solidify and to extend to long wavelengths the empirical calibration of the infrared spectral energy distribution (SED) of normal star-forming galaxies. As was found by Dale and coworkers in 2001, a single parameter family, characterized by fν(60μm)/fν(100μm), is adequate to describe the range of normal galaxy SEDs observed by the Infrared Astronomical Satellite and Infrared Space Observatory from 3 to 100 μm. However, predictions based on the first-generation models at longer wavelengths (122-850 μm) are increasingly overluminous compared to the data for smaller fν(60μm)/fν(100μm), or alternatively, for weaker global interstellar radiation fields. After slightly modifying the far-infrared/submillimeter dust emissivity in those models as a function of the radiation field intensity to better match the long-wavelength data, a suite of SEDs from 3 μm to 20 cm in wavelength is presented. Results from relevant applications are also discussed, including submillimeter-based photometric redshift indicators, the infrared energy budget and simple formulae for recovering the bolometric infrared luminosity, and dust mass estimates in galaxies. Regarding the latter, since galaxy infrared SEDs are not well described by single blackbody curves, the usual methods of estimating dust masses can be grossly inadequate. The improved model presented herein is used to provide a more accurate relation between infrared luminosity and dust mass.

  1. Application of far infrared rare earth mineral composite materials to liquefied petroleum gas.

    PubMed

    Zhu, Dongbin; Liang, Jinsheng; Ding, Yan; Xu, Anping

    2010-03-01

    Far infrared rare earth mineral composite materials were prepared by the coprecipitation method using tourmaline, cerium acetate, and lanthanum acetate as raw materials. The results of Fourier transform infrared spectroscopy show that tourmaline modified with the rare earths La and Ce has a better far infrared emitting performance. Through XRD analysis, we attribute the improved far infrared emission properties of the tourmaline to the unit cell shrinkage of the tourmaline arising from La enhancing the redox properties of nano-CeO2. The effect of the composite materials on the combustion of liquefied petroleum gas (LPG) was studied by the flue gas analysis and water boiling test. Based on the results, it was found that the composite materials could accelerate the combustion of LPG, and that the higher the emissivity of the rare earth mineral composite materials, the better the effects on combustion of LPG. In all activation styles, both air and LPG to be activated has a best effect, indicating the activations having a cumulative effect.

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

    PubMed

    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.

  3. Diffuse far-infrared [C II] line emission from high Galactic latitude

    NASA Astrophysics Data System (ADS)

    Makiuti, S.; Shibai, H.; Nakagawa, T.; Okuda, H.; Okumura, K.; Matsuhara, H.; Hiromoto, N.; Doi, Y.

    2002-02-01

    The Far-Infrared Line Mapper (FILM) onboard the Infrared Telescope in Space (IRTS) made a survey for the far-infrared [C Ii] 158 mu m line emission with high sensitivity and moderate spatial resolution. We have found that diffuse [C Ii] line emission extends to high Galactic latitude regions. The [C Ii] line intensity at | b | ~ 60deg ranges from 2*E-7 to 1.5*E-6 erg cm-2 s-1 sr-1. Comparisons of the distribution of the [C Ii] line emission with those of the H I column density and far-infrared radiation show some correlations, but the [C Ii] line emission differs from the far-IR and HI emission at high Galactic latitudes. These differences suggest that the [C Ii] line primarily comes from ionized gas in the high-latitude regions. The intensities of the [C Ii] line emission on the southern side (b < 0deg) of the Galactic plane are systematically larger than those on the northern side (b > 0deg). We infer from this difference that there is a displacement of the Sun with respect to the center of interstellar medium from which the [C Ii] line comes. When an exponential distribution is assumed for the [C Ii] emitting gas, it is expected that the Sun is located at the distance of about 17% of the scale height above the center of the gas. This is consistent with the previously reported displacement of the Sun from the Galactic plane.

  4. First Light from the Far-Infrared Spectroscopy of the Troposphere (FIRST) Instrument

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.; Johnson, David G.; Latvakoski, Harri; Jucks, Kenneth; Watson, Mike; Bingham, Gail; Kratz, David P.; Traub, Wesley A.; Wellard, Stanley J.; Hyde, Charles R.; Liu, Xu

    2005-01-01

    We present first light spectra from the new Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument. FIRST is a Fourier Transform Spectrometer developed to measure accurately the far-infrared (15 to 100 micrometers; 650 to 100 wavenumbers) emission spectrum of the Earth and its atmosphere. The observations presented here were obtained during a high altitude balloon flight from Ft. Sumner, New Mexico on 7 June 2005. The flight data demonstrate the instrument's ability to observe the entire energetically significant infrared emission spectrum (50 to 2000 wavenumbers) at high spectral and spatial resolution on a single focal plane in an instrument with one broad spectral bandpass beamsplitter. Comparisons with radiative transfer calculations demonstrate that FIRST accurately observes the very fine spectral structure in the far-infrared. Comparisons of the atmospheric window radiances measured by FIRST and by instruments on the NASA Aqua satellite that overflew FIRST are in excellent agreement. FIRST opens a new window on the spectrum that can be used for studying atmospheric radiation and climate, cirrus clouds, and water vapor in the upper troposphere.

  5. THE EXTRAORDINARY FAR-INFRARED VARIATION OF A PROTOSTAR: HERSCHEL/PACS OBSERVATIONS OF LRLL54361

    SciTech Connect

    Balog, Zoltan; Detre, Örs H.; Bouwmann, Jeroen; Nielbock, Markus; Klaas, Ulrich; Krause, Oliver; Henning, Thomas; Muzerolle, James; Flaherty, Kevin; Furlan, Elise; Gutermuth, Rob; Juhasz, Attila; Bally, John; Marton, Gabor

    2014-07-10

    We report Herschel/Photodetector Array Camera and Spectrometer (PACS) photometric observations at 70 μm and 160 μm of LRLL54361—a suspected binary protostar that exhibits periodic (P = 25.34 days) flux variations at shorter wavelengths (3.6 μm and 4.5 μm) thought to be due to pulsed accretion caused by binary motion. The PACS observations show unprecedented flux variation at these far-infrared wavelengths that are well correlated with the variations at shorter wavelengths. At 70 μm the object increases its flux by a factor of six while at 160 μm the change is about a factor of two, consistent with the wavelength dependence seen in the far-infrared spectra. The source is marginally resolved at 70 μm with varying FWHM. Deconvolved images of the sources show elongations exactly matching the outflow cavities traced by the scattered light observations. The spatial variations are anti-correlated with the flux variation, indicating that a light echo is responsible for the changes in FWHM. The observed far-infrared flux variability indicates that the disk and envelope of this source is periodically heated by the accretion pulses of the central source, and suggests that such long wavelength variability in general may provide a reasonable proxy for accretion variations in protostars.

  6. Non-destructively reading out information embedded inside real objects by using far-infrared light

    NASA Astrophysics Data System (ADS)

    Okada, Ayumi; Silapasuphakornwong, Piyarat; Suzuki, Masahiro; Torii, Hideyuki; Takashima, Youichi; Uehira, Kazutake

    2015-09-01

    This paper presents a technique that can non-destructively read out information embedded inside real objects by using far-infrared-light. We propose a technique that can protect the copyrights of digital content for homemade products using digital fabrication technologies such as those used in 3D printers. It embeds information on copyrights inside real objects produced by 3D printers by forming fine structures inside the objects as a watermark that cannot be observed from the outside. Fine structures are formed near the surface inside real objects when they are being fabricated. Information embedded inside real objects needs to be read out non-destructively. We used a technique that could non-destructively read out information from inside real objects by using far-infrared light. We conducted experiments where we structured fine cavities inside objects. The disposition of the fine domain contained valuable information. We used the flat and curved surfaces of the objects to identify them. The results obtained from the experiments demonstrated that the disposition patterns of the fine structures appeared on the surface of objects as a temperature profile when far-infrared light was irradiated on their surface. Embedded information could be read out successfully by analyzing the temperature profile images of the surface of the objects that were captured with thermography and these results demonstrated the feasibility of the technique we propose.

  7. Study of Several Potentials as Scalar Field Dark Matter Candidates

    SciTech Connect

    Matos, Tonatiuh; Vazquez-Gonzalez, Alberto; Magan a, Juan

    2008-12-04

    In this work we study several scalar field potentials as a plausible candidate to be the dark matter in the universe. The main idea is the following; if the scalar field is an ultralight boson particle, it condensates like a Bose-Einstein system at very early times and forms the basic structure of the Universe. Real scalar fields collapse in equilibrium configurations which oscillate in space-time (oscillatons). The cosmological behavior of the field equations are solved using the dynamical system formalism. We use the current cosmological parameters as constraints for the free parameters of the scalar field potentials. We are able to reproduce very well the cosmological predictions of the standard {lambda}CDM model with some scalar field potentials. Therefore, scalar field dark matter seems to be a good alternative to be the nature of the dark matter of the universe.

  8. Indium Hybridization of Large Format TES Bolometer Arrays to Readout Multiplexers for Far-Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Miller, Timothy M.; Costen, Nick; Allen, Christine

    2007-01-01

    The advance of new detector technologies combined with enhanced fabrication methods has resulted in an increase in development of large format arrays. The next generation of scientific instruments will utilize detectors containing hundreds to thousands of elements providing a more efficient means to conduct large area sky surveys. Some notable detectors include a 32x32 x-ray microcalorimeter for Constellation-X, an infrared bolometer called SAFIRE to fly on the airborne observatory SOFIA, and the sub-millimeter bolometer SCUBA-2 to be deployed at the JCMT which will use more than 10,000 elements for two colors, each color using four 32x40 arrays. Of these detectors, SCUBA-2 is farthest along in development and uses indium hybridization to multiplexers for readout of the large number of elements, a technology that will be required to enable the next generation of large format arrays. Our current efforts in working toward large format arrays have produced GISMO, the Goddard IRAM Superconducting 2-Millimeter observer. GISMO is a far infrared instrument to be field tested later this year at the IRAM 30 meter telescope in Spain. GISMO utilizes transition edge sensor (TES) technology in an 8x16 filled array format that allows for typical fan-out wiring and wire-bonding to four 1x32 NIST multiplexers. GISMO'S electrical wiring is routed along the tops of 30 micron walls which also serve as the mechanical framework for the array. This architecture works well for the 128 element array, but is approaching the limit for routing the necessary wires along the surface while maintaining a high fill factor. Larger format arrays will benefit greatly from making electrical connections through the wafer to the backside, where they can be hybridized to a read-out substrate tailored to handling the wiring scheme. The next generation array we are developing is a 32x40 element array on a pitch of 1135 microns that conforms to the NIST multiplexer, already developed for the SCUBA-2

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

    NASA Astrophysics Data System (ADS)

    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.

  10. A self-consistent analysis of far-infrared and submillimeter wavelength metal-grating free electron lasers

    NASA Astrophysics Data System (ADS)

    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 1 mm to 100 microns could be optimized at the output efficiencies around 1 percent with the use of a 100 keV to 1 MeV electron beam of current densities from 10 to 100(A/sq cm) and a 10 to 20 cm 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, output power and efficiency up to 600 watts, and 2 percent at about 35 GHz.

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

    NASA Astrophysics Data System (ADS)

    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

  12. Intersubband Rabi oscillations in asymmetric nanoheterostructures: implications for a tunable continuous-wave source of a far-infrared and THz radiation.

    PubMed

    Kukushkin, V A

    2012-06-01

    A tunable continuous-wave source of a far-infrared and THz radiation based on a semiconductor nanoheterostructure with asymmetric quantum wells is suggested. It utilizes Rabi oscillations at a transition between quantum well subbands excited by external femtosecond pulses of a mid-infrared electromagnetic field. Due to quantum well broken inversion symmetry the subbands possess different average dipole moments, which enables the creation of polarization at the Rabi frequency as the subband populations change. It is shown that if this polarization is excited so that it is periodic in space, then, though being pulsed, it can produce continuous-wave output radiation. Changing the polarization space period and the time intervals between the exciting pulses, one can tune the frequency of this radiation throughout the far-infrared and THz range. In the present work a concrete multiple quantum well heterostructure design and a scheme of its space-periodic polarization are suggested. It is shown that for existing sources of mid-infrared femtosecond pulses the proposed scheme can provide a continuous-wave output power of order the power of far-infrared and THz quantum cascade lasers. Being added to the possibility of its output frequency tuning, this can make the suggested device attractive for fundamental research and various applications.

  13. Effective field theory of dark matter: a global analysis

    NASA Astrophysics Data System (ADS)

    Liem, Sebastian; Bertone, Gianfranco; Calore, Francesca; de Austri, Roberto Ruiz; Tait, Tim M. P.; Trotta, Roberto; Weniger, Christoph

    2016-09-01

    We present global fits of an effective field theory description of real, and complex scalar dark matter candidates. We simultaneously take into account all possible dimension 6 operators consisting of dark matter bilinears and gauge invariant combinations of quark and gluon fields. We derive constraints on the free model parameters for both the real (five parameters) and complex (seven) scalar dark matter models obtained by combining Planck data on the cosmic microwave background, direct detection limits from LUX, and indirect detection limits from the Fermi Large Area Telescope. We find that for real scalars indirect dark matter searches disfavour a dark matter particle mass below 100 GeV. For the complex scalar dark matter particle current data have a limited impact due to the presence of operators that lead to p-wave annihilation, and also do not contribute to the spin-independent scattering cross-section. Although current data are not informative enough to strongly constrain the theory parameter space, we demonstrate the power of our formalism to reconstruct the theoretical parameters compatible with an actual dark matter detection, by assuming that the excess of gamma rays observed by the Fermi Large Area Telescope towards the Galactic centre is entirely due to dark matter annihilations. Please note that the excess can very well be due to astrophysical sources such as millisecond pulsars. We find that scalar dark matter interacting via effective field theory operators can in principle explain the Galactic centre excess, but that such interpretation is in strong tension with the non-detection of gamma rays from dwarf galaxies in the real scalar case. In the complex scalar case there is enough freedom to relieve the tension.

  14. Heavy dark matter annihilation from effective field theory.

    PubMed

    Ovanesyan, Grigory; Slatyer, Tracy R; Stewart, Iain W

    2015-05-29

    We formulate an effective field theory description for SU(2)_{L} triplet fermionic dark matter by combining nonrelativistic dark matter with gauge bosons in the soft-collinear effective theory. For a given dark matter mass, the annihilation cross section to line photons is obtained with 5% precision by simultaneously including Sommerfeld enhancement and the resummation of electroweak Sudakov logarithms at next-to-leading logarithmic order. Using these results, we present more accurate and precise predictions for the gamma-ray line signal from annihilation, updating both existing constraints and the reach of future experiments.

  15. Scalar field descriptions of two dark energy models

    NASA Astrophysics Data System (ADS)

    Panotopoulos, Grigorios

    2017-07-01

    We give a scalar field description of two dark energy parametrizations, and we analyze in detail its cosmology both at the level of background evolution and at the level of linear perturbations. In particular, we compute the statefinder parameters and the growth index as functions of the redshift for both dark energy parametrizations, and the comparison with the Λ CDM model as well as with a few well-known geometrical dark energy models is shown. In addition, the combination parameter A =f σ8 of both models is compared against current data.

  16. CROSS-CORRELATION OF NEAR- AND FAR-INFRARED BACKGROUND ANISOTROPIES AS TRACED BY SPITZER AND HERSCHEL

    SciTech Connect

    Thacker, Cameron; Gong, Yan; Cooray, Asantha; Mitchell-Wynne, Ketron; Bernardis, Francesco De; Smidt, Joseph

    2015-10-01

    We present the cross-correlation between the far-infrared (far-IR) background fluctuations as measured with the Herschel Space Observatory at 250, 350, and 500 μm and the near-infrared (near-IR) background fluctuations with the Spitzer Space Telescope at 3.6 and 4.5 μm. The cross-correlation between the FIR and NIR background anisotropies is detected such that the correlation coefficient at a few to 10 arcminute angular scale decreases from 0.3 to 0.1 when the FIR wavelength increases from 250 to 500 μm. We model the cross-correlation using a halo model with three components: (a) FIR bright or dusty star-forming galaxies below the masking depth in Herschel maps, (b) NIR faint galaxies below the masking depth, and (c) intra-halo light (IHL), or diffuse stars in dark matter halos, that is likely dominating the large-scale NIR fluctuations. The model is able to reasonably reproduce the auto-correlations at each of the FIR wavelengths and at 3.6 μm and their corresponding cross-correlations. While the FIR and NIR auto-correlations are dominated by faint, dusty, star-forming galaxies and IHL, respectively, we find that roughly half of the cross-correlation between the NIR and FIR backgrounds is due to the same dusty galaxies that remain unmasked at 3.6 μm. The remaining signal in the cross-correlation is due to IHL present in the same dark matter halos as those hosting the same faint and unmasked galaxies.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. A rocket-borne observation of the far-infrared sky at high Galactic latitude

    NASA Technical Reports Server (NTRS)

    Kawada, M.; Bock, J. J.; Hristov, V. V.; Lange, A. E.; Matsuhara, H.; Matsumoto, T.; Matsuura, S.; Mauskopf, P. D.; Richards, P. L.; Tanaka, M.

    1994-01-01

    We have measured the surface brightness of the far-infrared sky at lambda = 134, 154, and 186 micrometers at high Galactic latitude using a liquid-He-cooled, rocket-borne telescope. The telescope scanned over a 5 deg x 20 deg region which includes infrared cirrus, high-latitude molecular clouds, the starburst galaxy M82, and the H I Hole in Ursa Major, a region with uniquely low H I column density. The measured brightness at 134, 154, and 186 micrometers is well correlated with the 100 micrometers brightness measured by IRAS and, in regions excluding molecular clouds, with H I column density. The spectrum of the component correlated with H I is well fitted by a gray-body spectrum with a temperature of 16.4 (+2.3/-1.8) K, assuming an emissivity proportional to lambda(exp -2). Assuming a constant far-infrared dust emissivity per hydrogen nucleus, the ratio of the H2 column density to the velocity-integrated CO intensity in the high-latitude molecular cloud is NH2/W(sub co) = (1.6 +/- 0.3) x 10(exp 20)/sq cm/(K km/s). The residual brightness after subtracting the emission correlated with H I column density is lambda I(sub lambda)(154 micrometers) = (1.4 +/- 0.6) x 10(exp -12) W/sq cm/sr, yielding an upper limit to the far-infrared extragalactic background radiation of lambda I(sub lambda)(154 micrometers) is less than 2.6 x 10(exp -12) W/sq cm/sr.

  19. Retrieval of atmospheric parameters and radiative properties using Far-Infrared remote sensing measurements

    NASA Astrophysics Data System (ADS)

    Jamali, Maryam; Milz, Mathias; Martín-Torres, Javier; Palchetti, Luca

    2016-04-01

    The far-infrared (FIR) spectral region, covering wavelengths between 15 μm (667 cm-1) and about 1 μm (10,000 cm-1) plays a critical role in the climate system. A good knowledge of the radiation processes in this spectral region is of high interest for observations and understanding of heating and cooling rates, and global energy balance. Even though approximately 50% of terrestrial radiation occurs in the FIR and despite the critical FIR contribution to the Earth's energy balance, this spectral region has been only studied by a few number of instruments. Also the full FIR spectral region has not ever been directly observed from space. High spectral resolution observations in this region can help to enlighten its role for the global energy budget and atmospheric radiation processes. Among others, the reasons for this lack of measurements are: (i) the decreasing intensity of the radiation towards longer wavelengths; and, then (ii) the high sensitivity and cooling of the detectors requirements. These requirements are now overcome and future space missions will have the capability to measure the full FIR and then open fully one-half of the Earth's spectrum, and accordingly improve our ability to model and assess climate processes. The aim of the study is to assess the use of FIR remote sensing instruments for retrievals of atmospheric parameters and radiative properties such as heating and cooling rates. Case studies with simulated spectra, together with ground based measurements in the FIR at Dome C over the Antarctic Plateau at 3,230 m a.s.l. (above sea level) in clear-sky conditions, which been observed almost continuously since 2012, are used to assess the potential of remote sensing instruments in the far-infrared region. Appropriate selection of spectral channels to directly measure the far-infrared spectra as needed for future space missions and recommended.

  20. THE FAR-INFRARED SPECTROSCOPY OF VERY LARGE NEUTRAL POLYCYCLIC AROMATIC HYDROCARBONS

    SciTech Connect

    Ricca, Alessandra; Bauschlicher, Charles W.; Mattioda, Andrew L.; Boersma, Christiaan; Allamandola, Louis J.

    2010-01-20

    Here we report the computed far-infrared (FIR) spectra of neutral polycyclic aromatic hydrocarbon (PAH) molecules containing at least 82 carbons up to 130 carbons and with shapes going from compact round and oval-type structures to rectangular and to trapezoidal. The effects of size and shape on the FIR band positions and intensities are discussed. Using FIR data from the NASA Ames PAH IR Spectroscopic Database Version 1.1, we generate synthetic spectra that support the suggestion that the 16.4, 17.4, and 17.8 mum bands arise from PAHs.

  1. Superfluid-helium-cooled rocket-borne far-infrared radiometer.

    PubMed

    Blair, A G; Edeskuty, F; Hiebert, R D; Jones, D M; Shipley, J P; Williamson, K D

    1971-05-01

    A far-infrared radiometer, cooled to 1.6 K by superfluid helium, has been flown in a Terrier-Sandhawk rocket. The instrument was designed to measure night-sky radiation in three wavelength passbands between 6 mm and 0.1 mm at altitudes between 120 km and 350 km. A failure in the rocket nose cone separation system prevented the measurement of this radiation, but the performance of the instrument during flight was generally satisfactory. Design features and operational characteristics of the cryogenic, optical, detection, and electronic systems are presented.

  2. Far-infrared emission, gas, and ultraluminous HII regions in M101

    NASA Astrophysics Data System (ADS)

    Kenney, J. D. P.; Scoville, N. Z.

    We have made deconvolved maps of M101 in each of the 4 IRAS bands using a new maximum-entropy based model for reconstructing distributions with correlated structure on multiple scales. This new deconvolution procedure, developed by Weir (1992, J.Opt.Soc.Am., submitted), is superior to other maximum entropy-based techniques for several reasons. For our purposes, an important advantage is that it has less artifacts and greatly reduced systematic biases compared with the 'HiRes' maps of M101 produced by Aumann, Fowler, and Melnyk (1990, AJ, 99, 1674), thus it is accurate enough to perform aperture photometry. The deconvolved maps have a maximum resolution of approximately 30 sec, sufficient to resolve the brightest HII complexes and much of the spiral structure. The new maps and our comparison of the far-infrared, gas, and optical distributions are being written up in Kenney, Weir & Scoville (1992, in preparation). The quality of the reconstructed far-infrared maps is good enough for us to carry out most of the analyses outlined in the original proposal. From a ratio of the 60 micron and 100 micron maps, we have found that the ultraluminous HII complexes in the outer galaxy have the hottest dust temperatures with T approximately 50-60 K, which is twice as hot as most of the disk. Their extraordinary luminosity in the far-infrared is due to a relatively small amount of dust being heated to high temperatures, rather than a large concentration of dust and gas. A map of the dust opacity at 60 microns shows good overall agreement with a map of cold gas (HI+H2), indicating that throughout most of the galaxy only approximately 20 percent of the dust is warm enough to be detected by IRAS. The ultraluminous HII complexes have a high luminosity-to-gas mass ratio, independent of whether the far-infrared or the H-alpha emission line is used to measure the luminosity, which implies that gas is being converted into high mass stars more rapidly in these complexes compared to other

  3. Detection of pulsed far-infrared and terahertz light with an atomic force microscope

    NASA Astrophysics Data System (ADS)

    Ortega, J.-M.; Glotin, F.; Prazeres, R.; Berthet, J.-P.; Dazzi, A.

    2012-10-01

    We show that a commercial atomic force microscope can be used at room temperature as a detector throughout the infrared spectrum simply by recording the induced oscillation of its cantilever after irradiation by a pulsed laser. The oscillation amplitude can be made larger by spraying an absorbing graphite layer on the tip side. We demonstrate that its good sensitivity is due to a bilayer effect: their different thermal expansion coefficient forcing them to bend under irradiation. For the far-infrared spectral range, this device avoids the use of Helium cooled detectors and their numerous constraints.

  4. Computational design of solar reflection and far-infrared transmission films for a variable emittance device.

    PubMed

    Shimazaki, Kazunori; Ohnishi, Akira; Nagasaka, Yuji

    2003-03-01

    A smart radiation device (SRD) that is a variable emittance radiator has been studied as a method of thermal control for spacecraft. The SRD consists of manganese oxide with a perovskite-type structure, and the total hemispherical emittance of the SRD changes considerably depending on temperature. Here we propose an optimal method of designing multilayer films for the SRD by using agenetic algorithm. The multilayer films reflect solar radiation and transmit far-infrared radiation to maintain variation of the infrared optical properties of the SRD.

  5. Microstructure and far infrared emission properties of tourmaline powders eroded by hydrochloric acid.

    PubMed

    Liang, Jinsheng; Li, Juan; Meng, Junping; Ding, Yan; Xue, Gang

    2010-03-01

    The microstructure and far infrared emission properties of tourmaline powders eroded by hydrochloric acid were investigated. The indexes including crystal structure, unit cell volume, microstructure and infrared spectra were characterized by X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The results show that the crystal structure was not changed; however, the unit cell volume decreased, the angularities of tourmaline particles became smooth, and there appeared nanohollows on their surfaces. The infrared emission properties were enhanced at proper concentrations of hydrochloric acid solutions.

  6. Temperature dependence of optically dumped far-infrared (FIR) laser output power

    NASA Technical Reports Server (NTRS)

    Lawandy, N. M.

    1978-01-01

    The temperature dependence of the small signal gain and saturation power are derived using temperature-dependent rates in a four-level model. An expression is developed for the output power of a far-infrared oscillator as a function of temperature for both fixed pressure and fixed density. The results are valid in the regime of homogeneous broadening of the rotational transition and Doppler broadening of the pump transition. It is shown that, for most lasers, both the small signal gain and the saturation power decrease with increasing temperature. These effects have the overall result of increasing output power with decreasing temperatures.

  7. Far-infrared investigations of a methanol clathrate hydrate - Implications for astronomical observations

    NASA Technical Reports Server (NTRS)

    Hudson, Reggie L.; Moore, Marla H.

    1993-01-01

    Observations of nonterrestrial clathrate hydrates are still lacking despite the fact that clathrates first were suggested to exist in cometary and interstellar ices over 40 years ago. Spectroscopy, the most direct method of astronomical detection, has been hampered by the similarity of clathrate hydrate spectra to those of unenclathrated guest molecules and solid H2O. We have prepared a methanol (CH3OH) clathrate hydrate, using a recently published procedure, and have investigated its far-infrared spectrum. The spectrum is quite different from that of either unenclathrated CH3OH or solid H2O and so should be of value in astronomical searches for this clathrate.

  8. Method and means for generation of tunable laser sidebands in the far-infrared region

    NASA Technical Reports Server (NTRS)

    Pickett, Herbert M. (Inventor); Farhoomand, Jam (Inventor)

    1987-01-01

    A method for generating tunable far-infrared radiation is described. The apparatus includes a Schottky-barrier diode which has one side coupled through a conductor to a waveguide that carries a tunable microwave frequency; the diode has an opposite side which is coupled through a radiating whisker to a bias source. Infrared light is directed at the diode, and infrared light with tunable sidebands is radiated by the whisker through an open space to a reflector. The original infrared is separated from a tunable infrared sideband by a polarizing Michelson interferometer.

  9. Design of high-T{sub c} superconducting bolometers for a far infrared imaging array

    SciTech Connect

    Verghese, S.; Richards, P.L.; Fork, D.K.; Char, K.; Geballe, T.H.

    1992-08-01

    The design of high-{Tc} superconducting bolometers for use in a far infrared imaging array from wavelengths 30--100{mu}m is discussed. Measurements of the voltage noise in thin films of YBa{sub 2}CU{sub 3}O{sub 7-{var_sigma}} on yttria-stabilized zirconia buffer layers on silicon substrates are used to make performance estimates. Useful opportunities exist for imaging and spectroscopy with bolometer arrays made on micro-machined silicon membranes. A circuit on each pixel which performs some signal integration can improve the sensitivity of large two-dimensional arrays of bolometers which use multiplexed readout amplifiers.

  10. Non-Markovian far-infrared spectra of HCl and DCl in liquid SF6

    NASA Astrophysics Data System (ADS)

    Hernández, A. Calvo; Velasco, S.; Mauricio, F.

    1986-01-01

    The far-infrared spectrum of dilute solutions of HCl and DCl in liquid SF6 have been calculated by applying of two non-Markovian spectral theories previously reported in a recent work [A. Calvo Hernández, S. Velasco, and F. Mauricio, Phys. Rev. A 31, 3419 (1985)]. The calculated spectra are compared with the experimental spectra. Even though the systems under study are relatively far from the Markovian limit, the agreement between theoretical and experimental spectra shows the wide range of validity of both non-Markovian spectral theories.

  11. Probing the structures of gas-phase rhodium cluster cations by far-infrared spectroscopy

    SciTech Connect

    Harding, D. J.; Gruene, P.; Haertelt, M.; Meijer, G.; Fielicke, A.; Hamilton, S. M.; Hopkins, W. S.; Mackenzie, S. R.; Neville, S. P.; Walsh, T. R.

    2010-12-07

    The geometric structures of small cationic rhodium clusters Rh{sub n}{sup +} (n = 6-12) are investigated by comparison of experimental far-infrared multiple photon dissociation spectra with spectra calculated using density functional theory. The clusters are found to favor structures based on octahedral and tetrahedral motifs for most of the sizes considered, in contrast to previous theoretical predictions that rhodium clusters should favor cubic motifs. Our findings highlight the need for further development of theoretical and computational methods to treat these high-spin transition metal clusters.

  12. Upper limit for stratospheric HBr using far-infrared thermal emission spectroscopy

    NASA Technical Reports Server (NTRS)

    Traub, W. A.; Johnson, D. G.; Jucks, K. W.; Chance, K. V.

    1992-01-01

    An upper limit is measured for stratospheric HBr from three balloon flights. The observations were made with the FIRS-2 far-infrared Fourier transform spectrometer. The 1sigma upper limits from the 1988, 1989, and 1990 balloon flights are 13 pptv at 35 km, 7 pptv at 32 km, and 3 pptv at 31 km, respectively. Combining all 3 flights, the weighted average 1sigma upper limit for HBr is 4 pptv at 32 km. This value is significantly smaller than the only other previously published spectroscopic value of 20 +/- 7 pptv (2sigma), but is consistent with a theoretical estimate which predicts roughly 0.4 pptv at this altitude.

  13. Balloon-borne three-meter telescope for far-infrared and submillimeter astronomy

    NASA Technical Reports Server (NTRS)

    Fazio, Giovanni G.; Hoffmann, William F.; Harper, Doyal A.

    1988-01-01

    The scientific objectives, engineering analysis and design, results of technology development, and focal-plane instrumentation for a two-meter balloon-borne telescope for far-infrared and submillimeter astronomy are presented. The unique capabilities of balloon-borne observations are discussed. A program summary emphasizes the development of the two-meter design. The relationship of the Large Deployable Reflector (LDR) is also discussed. Detailed treatment is given to scientific objectives, gondola design, the mirror development program, experiment accommodations, ground support equipment requirements, NSBF design drivers and payload support requirements, the implementation phase summary development plan, and a comparison of three-meter and two-meter gondola concepts.

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

    SciTech Connect

    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.

  15. The Optical Properties of Solids in the Far Infrared and Submillimeter Regions.

    NASA Astrophysics Data System (ADS)

    Ordal, Mark Allen

    1985-12-01

    The optical properties of solids in the far infrared and submillimeter regions are treated in three manuscripts. The first manuscript approximates the optical constants of 14 metals with the Drude model. The second manuscript presents measured values for the absorption coefficient of Dupont Teflon FEP in the 20 to 130 cm('-1) region. The third manuscript describes an improved nonresonant cavity method for measuring the optical constants of metals at long wavelengths. In addition, the third manuscript presents preliminary nonresonant cavity measurements on Fe in the 64 to 322 cm('-1) region.

  16. Far infrared structure of spiral galaxies from the IRAS CPC images

    NASA Technical Reports Server (NTRS)

    Wainscoat, Richard J.; Chokshi, Arati; Doyle, Laurance R.

    1989-01-01

    Significant extended far infrared (50 micron and 100 micron) structure was found for five face-on spiral galaxies (NGC2403, M51, M83, NGC6946, and IC342) from fourteen galaxies searched in the Infrared Astronomy Satellite (IRAS) chopped photometric channel (CPC) catalogue. Images were initially processed to remove instrumental and background artifacts, the isophotal centroids of each image determined, and multiple images of each galaxy (for each wavelength) superimposed and averaged to improve signal-to-noise. Calibration of these images was performed using IRAS survey array data. Infrared isophotes were then superimposed on optical (blue) images so that direct structural comparisons could be made.

  17. Wavefront Sensing and Control Technology for Submillimeter and Far-Infrared Space Telescopes

    NASA Technical Reports Server (NTRS)

    Redding, Dave

    2004-01-01

    The NGST wavefront sensing and control system will be developed to TRL6 over the next few years, including testing in a cryogenic vacuum environment with traceable hardware. Doing this in the far-infrared and submillimeter is probably easier, as some aspects of the problem scale with wavelength, and the telescope is likely to have a more stable environment; however, detectors may present small complications. Since this is a new system approach, it warrants a new look. For instance, a large space telescope based on the DART membrane mirror design requires a new actuation approach. Other mirror and actuation technologies may prove useful as well.

  18. High frequency electron nuclear double resonance at 239 GHz using a far-infrared laser source

    SciTech Connect

    Paschedag, L.; van Tol, J.; Wyder, P.

    1995-10-01

    We report on the application of {sup 14}N electron nuclear double resonance (ENDOR) at 8.5 T and 239 GHz ({lambda}=1.2 mm) in a {gamma}-irradiated betaine arsenate single crystal. A laser was used as a far-infrared radiation source in a transmission-type electron paramagnetic resonance (EPR) setup without a cavity. The four expected nitrogen ENDOR lines were observed, but due to insufficient saturation of the EPR transitions the signal/noise ratio was not larger than 10 and the signals vanished at temperatures above 20 K. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  1. Far-infrared investigations of a methanol clathrate hydrate - Implications for astronomical observations

    NASA Technical Reports Server (NTRS)

    Hudson, Reggie L.; Moore, Marla H.

    1993-01-01

    Observations of nonterrestrial clathrate hydrates are still lacking despite the fact that clathrates first were suggested to exist in cometary and interstellar ices over 40 years ago. Spectroscopy, the most direct method of astronomical detection, has been hampered by the similarity of clathrate hydrate spectra to those of unenclathrated guest molecules and solid H2O. We have prepared a methanol (CH3OH) clathrate hydrate, using a recently published procedure, and have investigated its far-infrared spectrum. The spectrum is quite different from that of either unenclathrated CH3OH or solid H2O and so should be of value in astronomical searches for this clathrate.

  2. Analyzing Microchips With Dark-Field Negative Photomicrography

    NASA Technical Reports Server (NTRS)

    Suszko, S. F.

    1985-01-01

    Inverse development process yields fine details. Photomicrographic technique produces images of integrated-circuit chips. Technique based on dark-field illumination: (chip lit with bright central spot of light and photographed by light scattered or diffracted from spot. Reveals more about microstructure patterns related to photoresist masking than more conventional bright-field method.

  3. Analyzing Microchips With Dark-Field Negative Photomicrography

    NASA Technical Reports Server (NTRS)

    Suszko, S. F.

    1985-01-01

    Inverse development process yields fine details. Photomicrographic technique produces images of integrated-circuit chips. Technique based on dark-field illumination: (chip lit with bright central spot of light and photographed by light scattered or diffracted from spot. Reveals more about microstructure patterns related to photoresist masking than more conventional bright-field method.

  4. Bose-Einstein condensates from scalar field dark matter

    SciTech Connect

    Urena-Lopez, L. Arturo

    2010-12-07

    We review the properties of astrophysical and cosmological relevance that may arise from the bosonic nature of scalar field dark matter models. The key property is the formation of Bose-Einstein condensates, but we also consider the presence of non-empty excited states that may be relevant for the description of scalar field galaxy halos and the properties of rotation curves.

  5. OH far-infrared emission from low- and intermediate-mass protostars surveyed with Herschel-PACS

    NASA Astrophysics Data System (ADS)

    Wampfler, S. F.; Bruderer, S.; Karska, A.; Herczeg, G. J.; van Dishoeck, E. F.; Kristensen, L. E.; Goicoechea, J. R.; Benz, A. O.; Doty, S. D.; McCoey, C.; Baudry, A.; Giannini, T.; Larsson, B.

    2013-04-01

    Context. The OH radical is a key species in the water chemistry network of star-forming regions, because its presence is tightly related to the formation and destruction of water. Previous studies of the OH far-infrared emission from low- and intermediate-mass protostars suggest that the OH emission mainly originates from shocked gas and not from the quiescent protostellar envelopes. Aims: We aim to study the excitation of OH in embedded low- and intermediate-mass protostars, determine the influence of source parameters on the strength of the emission, investigate the spatial extent of the OH emission, and further constrain its origin. Methods: This paper presents OH observations from 23 low- and intermediate-mass young stellar objects obtained with the PACS integral field spectrometer on-board Herschel in the context of the "Water In Star-forming regions with Herschel" (WISH) key program. Radiative transfer codes are used to model the OH excitation. Results: Most low-mass sources have compact OH emission (≲5000 AU scale), whereas the OH lines in most intermediate-mass sources are extended over the whole 47.″0 × 47.″0 PACS detector field-of-view (≳20 000 AU). The strength of the OH emission is correlated with various source properties such as the bolometric luminosity and the envelope mass, but also with the [OI] and H2O emission. Rotational diagrams for sources with many OH lines show that the level populations of OH can be approximated by a Boltzmann distribution with an excitation temperature at around 70 K. Radiative transfer models of spherically symmetric envelopes cannot reproduce the OH emission fluxes nor their broad line widths, strongly suggesting an outflow origin. Slab excitation models indicate that the observed excitation temperature can either be reached if the OH molecules are exposed to a strong far-infrared continuum radiation field or if the gas temperature and density are sufficiently high. Using realistic source parameters and

  6. Far-Infrared Extinction Mapping: a window to the darkest depths

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan

    Star formation is a complex process. Progress in its understanding requires detailed observational constraints on the initial conditions, i.e., dense clumps and cores in giant molecular clouds (GMCs). Such structures have been studied by their extinction of NearInfrared (NIR) and Mid-Infrared (MIR) background light in Infrared Dark Clouds (IRDCs). More recently, with the resolution and sensitivity of Herschel images, regions appearing as dark shadows at Far-Infrared (FIR) wavelengths up to 160 ¼m have been discovered! The goal of this proposal is to develop analysis methods of FIR extinction (FIREX) mapping using images from Spitzer-MIPS at 24 ¼m and Herschel-PACS at 70, 100 and 160 ¼m that allow quantitative measurements of cloud column density, temperature and MIR-FIR dust opacity structures, building on the exploratory work of Lim & Tan (2014, hereafter LT14). This technique has two main advantages over the more commonly used method of fitting grey-body models to FIR and sub-mm emission: firstly, by having higher angular resolution, especially the common 6 resolution of Spitzer-MIPS at 24¼m and Herschel-PACS at 70 ¼m; secondly, by being independent of the dust temperature, if lower than a given critical value. Furthermore, FIREX mapping has an advantage over NIR & MIR extinction (NIREX/MIREX) mapping of being able to probe to higher column densities. We will: (1) Develop the FIREX mapping methods of LT14, including expanding the sample from 1 to 10 IRDCs that will require new methods to allow for unsaturated cases where a cloud s densest region does not effectively block all the background emission. This will involve accurate measurement of the MIR to FIR spectral energy distribution (SED) of the diffuse interstellar medium dust in the local Galactic plane. We will also make extinction maps over entire IRDCs, rather than just localized clumps of LT14, by modeling foreground intensity variations. We will analyze data at additional wavelengths, i.e., 12

  7. Hyperspectral dark-field microscopy of gold nanodisks.

    PubMed

    Grasseschi, Daniel; Lima, Filipe S; Nakamura, Marcelo; Toma, Henrique E

    2015-02-01

    The light scattering properties of hexagonal and triangular gold nanodisks were investigated by means of Cytoviva hyperspectral dark-field microscopy, exploring the huge enhancement of the scattered waves associated with the surface plasmon resonance (SPR) effect. Thanks to the high resolution capability of the dark-field microscope, the SPR effect turned it possible to probe the individual nanoparticles directly from their hyperspectral images, extrapolating the classical optical resolution limit, and providing their corresponding extinction spectra. Blue spectral shifts involving the in-plane dipolar modes were observed for the hexagonal gold nanodisks in relation to the triangular ones, allowing their spectroscopic differentiation in the dark-field images. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Energy weighted x-ray dark-field imaging.

    PubMed

    Pelzer, Georg; Zang, Andrea; Anton, Gisela; Bayer, Florian; Horn, Florian; Kraus, Manuel; Rieger, Jens; Ritter, Andre; Wandner, Johannes; Weber, Thomas; Fauler, Alex; Fiederle, Michael; Wong, Winnie S; Campbell, Michael; Meiser, Jan; Meyer, Pascal; Mohr, Jürgen; Michel, Thilo

    2014-10-06

    The dark-field image obtained in grating-based x-ray phase-contrast imaging can provide information about the objects' microstructures on a scale smaller than the pixel size even with low geometric magnification. In this publication we demonstrate that the dark-field image quality can be enhanced with an energy-resolving pixel detector. Energy-resolved x-ray dark-field images were acquired with a 16-energy-channel photon-counting pixel detector with a 1 mm thick CdTe sensor in a Talbot-Lau x-ray interferometer. A method for contrast-noise-ratio (CNR) enhancement is proposed and validated experimentally. In measurements, a CNR improvement by a factor of 1.14 was obtained. This is equivalent to a possible radiation dose reduction of 23%.

  9. Study for the analysis of the observations, and numerical data representing the planets as far-infrared calibration sources

    NASA Technical Reports Server (NTRS)

    Wu, Shi Tsan; Zhou, Minggang

    1994-01-01

    The existing radiative transfer and inversion programs will be modified for application to the atmospheres of Uranus, Neptune, and Jupiter. The programs will be employed for analysis of KAO planetary observations in order to develop far infrared photometric calibration standards. This work will be carried out on MSFC computers. The expected end product of this task is a working program for analysis of the observations, and numerical data representing the planets as far-infrared calibration sources.

  10. Towards Background-Limited Kinetic Inductance Detectors for a Cryogenic Far-Infrared Space Telescope

    NASA Astrophysics Data System (ADS)

    Fyhrie, A.; Glenn, J.; Wheeler, J.; Day, P.; Eom, B. H.; Leduc, H.; Skrutskie, M.

    2016-08-01

    Arrays of tens of thousands of sensitive far-infrared detectors coupled to a cryogenic 4-6 m class orbital telescope are needed to trace the assembly of galaxies over cosmic time. The sensitivity of a 4 Kelvin telescope observing in the far-infrared (30-300 \\upmu m) would be limited by zodiacal light and Galactic interstellar dust emission, and require broadband detector noise equivalent powers (NEPs) in the range of 3× 10^{-19} W/√{Hz}. We are fabricating and testing 96 element arrays of lumped-element kinetic inductance detectors (LEKIDs) designed to reach NEPs near this level in a low-background laboratory environment. The LEKIDs are fabricated with aluminum: the low normal-state resistivity of Al permits the use of very thin wire-grid absorber lines (150 nm) for efficient absorption of radiation, while the small volumes enable high sensitivities because quasiparticle densities are high. Such narrow absorption lines present a fabrication challenge, but we deposit TiN atop the Al to increase the robustness of the detectors and achieve a 95 % yield. We present the design of these Al/TiN bilayer LEKIDs and preliminary sensitivity measurements at 350 \\upmu m optically loaded by cold blackbody radiation.

  11. A CO and far-infrared study of the S254-S258 region

    NASA Technical Reports Server (NTRS)

    Heyer, Mark H.; Snell, Ronald L.; Morgan, James; Schloerb, F. Peter

    1989-01-01

    The molecular cloud associated with compact radio and bright optical H II regions is studied from observations of (C-12)O, (C-13)O, HCN J = 1-0 emission. The far-infrared and millimeter molecular line emission from the S254-S258 molecular cloud is analyzed, using co-added survey data from IRAS, to investigate the coupling between the dust and gas components and the internal energetics associated with molecular clouds. The dust component is analyzed by fitting model intensities, derived from a dust mass column density temperature relation, to the observed far-infrared emission. Such modeling is shown to provide a more complete description of the cold dust component which comprises most of the dust mass than can be determined from the standard single temperature analysis. Local heating of the dust component by newborn massive stars associated with the H II regions of the cloud is inferred from the spatial distribution of temperatures of grains which make the largest contributions to the observed 60 and 100 micron emission.

  12. Far infrared spectra of solid state aliphatic amino acids in different protonation states

    NASA Astrophysics Data System (ADS)

    Trivella, Aurélien; Gaillard, Thomas; Stote, Roland H.; Hellwig, Petra

    2010-03-01

    Far infrared spectra of zwitterionic, cationic, and anionic forms of aliphatic amino acids in solid state have been studied experimentally. Measurements were done on glycine, L-alanine, L-valine, L-leucine, and L-isoleucine powder samples and film samples obtained from dried solutions prepared at pH ranging from 1 to 13. Solid state density functional theory calculations were also performed, and detailed potential energy distributions were obtained from normal mode results. A good correspondence between experimental and simulated spectra was achieved and this allowed us to propose an almost complete band assignment for the far infrared spectra of zwitterionic forms. In the 700-50 cm-1 range, three regions were identified, each corresponding to a characteristic set of normal modes. A first region between 700 and 450 cm-1 mainly contained the carboxylate bending, rocking, and wagging modes as well as the ammonium torsional mode. The 450-250 cm-1 region was representative of backbone and sidechain skeletal bending modes. At last, the low wavenumber zone, below 250 cm-1, was characteristic of carboxylate and skeletal torsional modes and of lattice modes. Assignments are also proposed for glycine cationic and anionic forms, but could not be obtained for all aliphatic amino acids due to the lack of structural data. This work is intended to provide fundamental information for the understanding of peptides vibrational properties.

  13. Performance and application of far infrared rays emitted from rare earth mineral composite materials.

    PubMed

    Liang, Jinsheng; Zhu, Dongbin; Meng, Junping; Wang, Lijuan; Li, Fenping; Liu, Zhiguo; Ding, Yan; Liu, Lihua; Liang, Guangchuan

    2008-03-01

    Rare earth mineral composite materials were prepared using tourmaline and cerous nitrate as raw materials. Through characterization by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, dynamic contact angle meter and tensiometer, and Fourier transform infrared spectroscopy, it was found that the composite materials had a better far infrared emitting performance than tourmaline, which depended on many factors such as material composition, microstructure, and surface free energy. Based on the results of the flue gas analyzer and the water boiling test, it was found that the rare earth mineral composite materials could accelerate the combustion of liquefied petroleum gas and diesel oil. The results showed that the addition of Ce led to the improvement of far infrared emitting performance of tourmaline due to the decrease of cell volume caused by the oxidation of more Fe2+ ions and the increase of surface free energy. The application of rare earth mineral composite materials to diesel oil led to a decrease in surface tension and flash point, and the fuel saving ratio could reach 4.5%. When applied to liquefied petroleum gas, the composite materials led to the enhanced combustion, improved fuel consumption by 6.8%, and decreased concentration of CO and O2 in exhaust gases by 59.7% and 16.2%, respectively; but the temperature inside the flue increased by 10.3%.

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

    PubMed

    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 < 0.01, which means that the effect is significant. It can be explained that the water activated by the 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.

  15. H-ATLAS: the far-infrared properties of galaxies in and around the Coma cluster

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    We describe a far-infrared survey of the Coma cluster and the galaxy filament it resides within. Our survey covers an area of ˜150 deg2 observed by Herschel H-ATLAS (Herschel Astrophysical Terahertz Large Area Survey) in five bands at 100, 160, 250, 350 and 500 μm. The SDSS spectroscopic survey (mr ≤ 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. For comparison, we also define a sample of 951 galaxies in the connecting filament - the Coma Filament Catalogue. 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 per cent) and 422 of 951 (44 per cent) of the cluster and filament galaxies in the SPIRE 250 μm 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 find no differences between the dust masses and temperatures of cluster and filament galaxies with the exception of early-type galaxy dust temperatures, which are significantly hotter in the cluster than in the filament (X-ray heating?). From a chemical evolution model, we find no evidence for different evolutionary processes (gas loss or infall) between galaxies in the cluster and filament.

  16. The nature of the emission-line nebulae in powerful far-infrared galaxies

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    The authors discuss their program of narrow-band (H alpha + (NII)) imaging of a sample of 30 powerful far-infrared galaxies (FIRG's) chosen to have far-infrared spectral energy distributions similar to the prototype FIRG's Arp 220, NGC 3690, NGC 6240, and M82. The emission-line nebulae of these IR color-selected sample (ICSS) galaxies as a class are both impressively large (mean half light radius, r approx. 1.3 Kpc, and mean diameter, D approx. 16 Kpc) and luminous (L sub TOT approx. 10(exp 8) solar lumninosity; uncorrected for internal extinction). The mean total H alpha + (NII) luminosity of the FIRG's is comparable to that found for pairs of optically selected interacting galaxies (Bushouse, Lamb, and Werner 1988), but is a factor of approx. 5 greater than that of isolated spirals (Kennicutt and Kent 1983). Only approx. 25 percent of the nearby (z approx. less than 0.10) FIRG's have morphologies suggesting that large HII-regions contribute significantly to their emission-line appearance. The broad-band morphologies of our IR color-selected galaxies fall into three major categories. Nearly 75 percent are single galaxy systems, with the remaining FIRG's being either multiple nuclei systems, or members of interacting pairs. Since the authors saw few (10 percent) currently interacting FIRG's, yet many (80 percent) with highly distorted continuum morphologies, their IR color criteria may be preferentially selecting galaxies that have undergone highly inelastic, rapidly merging interactions.

  17. Far infrared spectra of solid state aliphatic amino acids in different protonation states.

    PubMed

    Trivella, Aurélien; Gaillard, Thomas; Stote, Roland H; Hellwig, Petra

    2010-03-21

    Far infrared spectra of zwitterionic, cationic, and anionic forms of aliphatic amino acids in solid state have been studied experimentally. Measurements were done on glycine, L-alanine, L-valine, L-leucine, and L-isoleucine powder samples and film samples obtained from dried solutions prepared at pH ranging from 1 to 13. Solid state density functional theory calculations were also performed, and detailed potential energy distributions were obtained from normal mode results. A good correspondence between experimental and simulated spectra was achieved and this allowed us to propose an almost complete band assignment for the far infrared spectra of zwitterionic forms. In the 700-50 cm(-1) range, three regions were identified, each corresponding to a characteristic set of normal modes. A first region between 700 and 450 cm(-1) mainly contained the carboxylate bending, rocking, and wagging modes as well as the ammonium torsional mode. The 450-250 cm(-1) region was representative of backbone and sidechain skeletal bending modes. At last, the low wavenumber zone, below 250 cm(-1), was characteristic of carboxylate and skeletal torsional modes and of lattice modes. Assignments are also proposed for glycine cationic and anionic forms, but could not be obtained for all aliphatic amino acids due to the lack of structural data. This work is intended to provide fundamental information for the understanding of peptides vibrational properties.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Radio continuum and far-infrared observations of low surface brightness galaxies

    NASA Technical Reports Server (NTRS)

    Hoeppe, G.; Brinks, E.; Klein, U.; Giovanardi, C.; Altschuler, D. R.; Price, R. M.; Deeg, H. -J.

    1994-01-01

    We present Very Large Array (VLA) radio continuum and Infrared Astronomy Satellite (IRAS) far-infrared (FIR) observations of 16 low luminosity galaxies of mostly low surface brightness. All galaxies had previously claimed single dish radio continuum detections. However, at the frequencies of our observations (1.49 and 8.48 GHz), we find significant radio emission for two objects only. We show that the other previously claimed detections are due to confusion with physically unrelated background sources. This implies a low radio continuum detection rate for these galaxies. Re-reduced IRAS scans yield significant far-infrared flux densities in at least one IRAS band for 6 of the 16 galaxies. These, together with the FIR and radio continuum upper limits, are consistent with the well established radio/FIR relation, where most of our galaxies populate the low-luminosity end. From the radio continuum and FIR flux densities and their upper limits we estimate the current star formation rates and demonstrate that the galaxies are currently passive in forming stars, in agreement with previous optical investigations. There is an indication that the galaxies were forming stars more intensively averaged over their lifetime than they are presently.

  20. Characterization of liquid phase epitaxial GaAs forblocked-impurity-band far-infrared detectors

    SciTech Connect

    Cardozo, B.L.; Reichertz, L.A.; Beeman, J.W.; Haller, E.E.

    2004-04-07

    GaAs Blocked-Impurity-Band (BIB) photoconductor detectors have the potential to become the most sensitive, low noise detectors in the far-infrared below 45.5 cm{sup -1} (220 {micro}m). We have studied the characteristics of liquid phase epitaxial GaAs films relevant to BIB production, including impurity band formation and the infrared absorption of the active section of the device. Knowledge of the far-infrared absorption spectrum as a function of donor concentration combined with variable temperature Hall effect and resistivity studies leads us to conclude that the optimal concentration for the absorbing layer of a GaAs BIB detector lies between 1 x 10{sup 15} and 6.7 x 10{sup 15} cm{sup -3}. At these concentrations there is significant wavefunction overlap which in turn leads to absorption beyond the 1s ground to 2p bound excited state transition of 35.5 cm{sup -1} (282 {micro}m). There still remains a gap between the upper edge of the donor band and the bottom of the conduction band, a necessity for proper BIB detector operation.

  1. Cryogenic far-infrared laser absorptivity measurements of the Herschel Space Observatory telescope mirror coatings.

    PubMed

    Fischer, Jacqueline; Klaassen, Tjeerd; Hovenier, Niels; Jakob, Gerd; Poglitsch, Albrecht; Sternberg, Oren

    2004-07-01

    Far-infrared laser calorimetry was used to measure the absorptivity, and thus the emissivity, of aluminum-coated silicon carbide mirror samples produced during the coating qualification run of the Herschel Space Observatory telescope to be launched by the European Space Agency in 2007. The samples were measured at 77 K to simulate the operating temperature of the telescope in its planned orbit about the second Lagrangian point, L2, of the Earth-Sun system. Together, the telescope's equilibrium temperature in space and the emissivity of the mirror surfaces will determine the far-infrared-submillimeter background and thus the sensitivity of two of the three astronomical instruments aboard the observatory if stray-light levels can be kept low relative to the mirror emission. Absorptivities of both clean and dust-contaminated samples were measured at 70, 118, 184, and 496 microm. Theoretical fits to the data predict absorptivities of 0.2-0.4% for the clean sample and 0.2-0.8% for the dusty sample, over the spectral range of the Herschel Space Observatory instruments.

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

    PubMed

    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.

  3. THE SPECTRAL ENERGY DISTRIBUTION OF THE CARINA NEBULA FROM FAR-INFRARED TO RADIO WAVELENGTHS

    SciTech Connect

    Salatino, M.; De Bernardis, P.; Masi, S.; Polenta, G.

    2012-03-20

    Multi-wavelength observations are necessary for understanding the physical properties of astrophysical sources. In this paper, we use observations in the far-infrared to radio range to derive the spectral energy distribution (SED) of the Carina nebula. To do this, we carefully subtract the irregularly varying diffuse emission from the Galactic plane, which can be of the order of 10% of the nebula flux at these wavelengths. We find that the far-infrared SED can be modeled as emission from a dust population with a single temperature T{sub d} = (34.5{sup +2.0}{sub -1.8}) K and with a spectral index of emissivity {alpha} = -1.37{sup +0.09}{sub -0.08}. We also find a total infrared luminosity of the nebula of (7.4{sup +2.5}{sub -1.4}) Multiplication-Sign 10{sup 6} L{sub Sun} and, assuming a single temperature of the dust, a mass of the dust of (9500{sup +4600}{sub -3500}) M{sub Sun }.

  4. Extended far-infrared emission and star formation in Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Marston, A. P.

    1994-01-01

    An investigation into the extended distribution of far-infrared (FIR) emission associated with nearby Seyfert galaxies is made using a set of MEM reconstructions of IRAS Chopped Photometric Channel (CPC) data (Marston 1993). The data is compared to a set of HII/starburst galaxy images similarly processed in order to compare distributions and FIR color properties. It is shown that the central 1 kpc or so of Seyfert galaxies show extended FIR emission. FIR colors suggest that the bulk of this emission is not directly associated with an active nucleus. They further suggest that the origins of the majority of the emission is from heated dust associated with star formation surrounding the nucleus rather than dust heated by the active nucleus. Nearby Seyfert galaxies are shown to have a higher concentration of far-infrared emission from their centers than the HII/starburst galaxies and a number appear to reside in disk galaxies with relatively low ongoing star formation in their disks. An example of this is NGC 7582 which has a smooth disk but an active nucleus/starbust center.

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

    NASA Astrophysics Data System (ADS)

    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 < λ < 1 mm) are excellent tracers of star formation, but detecting them requires the next generation of sensitive detectors. We are 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.

  6. Carbon monoxide and far-infrared observations of the S 155-Cepheus B region

    NASA Astrophysics Data System (ADS)

    Minchin, Nigel R.; Ward-Thompson, Derek; White, Glenn J.

    1992-11-01

    We present maps of the CO J = 3-2 and (C-13)O J = 2-1 molecular line and mid- to far-infrared continuum emission of the interface between the Cepheus B molecular cloud and the S155 H II region. Far-infrared dust color temperature and optical depth maps show the molecular cloud to be externally heated and that the edge of the cloud is compressed by the expansion of S155. The data are compared with current models, and various dust grain parameters are derived. A hotspot is observed in the CO J = 3-2 emission line, at a position coincident with the radio continuum and infrared emission peaks. The infrared, radio continuum, and molecular line emission from the hotspot are all consistent with it being a compact H II region, ionized by an embedded B1-B0.5 star. The position of the compact H II region, adjacent to the northwestern edge of Cep B, suggests it is the product of a phase of sequential OB star formation.

  7. Far-infrared and sub-millimetre imaging of HD 76582's circumstellar disc

    NASA Astrophysics Data System (ADS)

    Marshall, Jonathan P.; Booth, Mark; Holland, Wayne; Matthews, Brenda C.; Greaves, Jane S.; Zuckerman, Ben

    2016-07-01

    Debris discs, 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 disc 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 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 disc 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 μm reveals a steep fall-off that we interpret as a disc dominated by moderately sized dust grains (amin = 36 μm), perhaps indicative of a non-steady-state collisional cascade within the disc. A disc architecture of three distinct annuli, comprising an unresolved component at 20 au and outer components at 80 and 270 au, along with a very steep particle size distribution (γ = 5), is proposed to match the observations.

  8. Drying effects of vacuum far-infrared on aquilaria malaccensis leaves

    NASA Astrophysics Data System (ADS)

    Alwi, Habsah; Abdulbari Ali, Sherif; Hamid, Ku Halim Ku; Zaid Shamsudin, Mohamad; Che Radzi, Nurhaslina; Zaki, Nurul Asyikin Md; Najwa Muhd, Miradatul

    2017-08-01

    Vacuum far-infrared radiation is an advanced drying technique that has the unique characteristics of energy transfer mechanism. In vacuum drying, the moisture evaporates at lower temperature while in infrared drying, the energy is absorbed directly which save a considerable amount of energy. The combination of the two would results in the time savings and enhancement of product quality. The effects of vacuum far-infrared drying on colour changes, elements and moisture content removal of Aquilaria Malaccensis’ leaves were investigated. The parameter of the experiments were set to be temperature of 40, 50 and 60 °C, pressure of 0.6 and 0.8 bar, and a residence time of 120 minutes. The drying process reaches it optimum condition at temperature of 50°C and pressure of 0.6 bar, where the colour changes of the leaves, moisture content removal and elemental analyzer showed the best result of all six runs. The optimum drying conditions are recommended for further researches of the leaves.

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

    PubMed Central

    Ke, Yu-Min; Ou, Ming-Chiu; Ho, Cheng-Kun; Lin, Yung-Sheng; Liu, Ho-Yen; Chang, Wen-An

    2012-01-01

    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. PMID:23320024

  10. BLAST: A FAR-INFRARED MEASUREMENT OF THE HISTORY OF STAR FORMATION

    SciTech Connect

    Pascale, Enzo; Ade, Peter A. R.; Dye, Simon; Eales, Steve A.; Griffin, Matthew; Hargrave, Peter C.; Mauskopf, Philip; Moncelsi, Lorenzo; Bock, James J.; Chapin, Edward L.; Halpern, Mark; Marsden, Gaelen; Ngo, Henry; Devlin, Mark J.; Klein, Jeff; Gundersen, Joshua O.; Hughes, David H.; Netterfield, Calvin B.; Olmi, Luca; Patanchon, Guillaume

    2009-12-20

    We directly measure redshift evolution in the mean physical properties (far-infrared luminosity, temperature, and mass) of the galaxies that produce the cosmic infrared background (CIB), using measurements from the Balloon-borne Large Aperture Submillimeter Telescope (BLAST), and Spitzer which constrain the CIB emission peak. This sample is known to produce a surface brightness in the BLAST bands consistent with the full CIB, and photometric redshifts are identified for all of the objects. We find that most of the 70 mum background is generated at z approx< 1 and the 500 mum background generated at z approx> 1. A significant growth is observed in the mean luminosity from approx10{sup 9}-10{sup 12} L{sub sun}, and in the mean temperature by 10 K, from redshifts 0 < z < 3. However, there is only weak positive evolution in the comoving dust mass in these galaxies across the same redshift range. We also measure the evolution of the far-infrared luminosity density, and the star formation rate history for these objects, finding good agreement with other infrared studies up to z approx 1, exceeding the contribution attributed to optically selected galaxies.

  11. Far-infrared spectroscopy of the troposphere: instrument description and calibration performance.

    PubMed

    Latvakoski, Harri; Mlynczak, Martin G; Johnson, David G; Cageao, Richard P; Kratz, David P; Johnson, Kendall

    2013-01-10

    The far-infrared spectroscopy of the troposphere (FIRST) instrument is a Fourier transform spectrometer developed to measure the Earth's thermal emission spectrum with a particular emphasis on far-infrared (far-IR) wavelengths greater than 15 μm. FIRST was developed under NASA's Instrument Incubator Program to demonstrate technology for providing measurements from 10 to 100 μm (1000 to 100 cm(-1)) on a single focal plane with a spectral resolution finer than 1 cm(-1). Presently no spectrometers in orbit are capable of directly observing the Earth's far-IR spectrum. This fact, coupled with the fundamental importance of the far-IR to Earth's climate system, provided the impetus for the development of FIRST. In this paper the FIRST instrument is described and results of a detailed absolute laboratory calibration are presented. Specific channels in FIRST are shown to be accurate in the far-IR to better than 0.3 K at 270 K scene temperature, 0.5 K at 247 K, and 1 K at 225 K.

  12. Far-infrared spectroscopy of the troposphere: calibration with a cold background.

    PubMed

    Latvakoski, Harri; Mlynczak, Martin G; Cageao, Richard P; Johnson, David G; Kratz, David P

    2014-08-20

    The far-infrared spectroscopy of the troposphere (FIRST) instrument is a Fourier-transform spectrometer developed to measure the Earth's thermal emission spectrum with a particular emphasis on the far-infrared. FIRST has observed the atmosphere from both the ground looking up and from a high-altitude balloon looking down. A recent absolute laboratory calibration of FIRST under ground-like operating conditions showed accuracy to better than 0.3 K at near-ambient temperatures (270-325 K) but reduced accuracy at lower temperatures. This paper presents calibration results for balloon-flight conditions using a cold blackbody to simulate the space view used for on-board calibration. An unusual detector nonlinearity was discovered and corrected, and stray light was measured and removed. Over most of the range of Earth scene temperatures (205-300 K), the accuracy of FIRST is 0.35-0.15 K (one sigma).

  13. Far-infrared absorption of water clusters by first-principles molecular dynamics.

    PubMed

    Lee, Mal-Soon; Baletto, F; Kanhere, D G; Scandolo, S

    2008-06-07

    Based on first-principle molecular dynamic simulations, we calculate the far-infrared spectra of small water clusters (H(2)O)(n) (n = 2, 4, 6) at frequencies below 1000 cm(-1) and at 80 K and at atmospheric temperature (T>200 K). We find that cluster size and temperature affect the spectra significantly. The effect of the cluster size is similar to the one reported for confined water. Temperature changes not only the shape of the spectra but also the total strength of the absorption, a consequence of the complete anharmonic nature of the classical dynamics at high temperature. In particular, we find that in the frequency region up to 320 cm(-1), the absorption strength per molecule of the water dimer at 220 K is significantly larger than that of bulk liquid water, while tetramer and hexamer show bulklike strengths. However, the absorption strength of the dimer throughout the far-infrared region is too small to explain the measured vapor absorption continuum, which must therefore be dominated by other mechanisms.

  14. Dark energy cosmology with tachyon field in teleparallel gravity

    SciTech Connect

    Motavalli, H. Akbarieh, A. Rezaei; Nasiry, M.

    2016-07-15

    We construct a tachyon teleparallel dark energy model for a homogeneous and isotropic flat universe in which a tachyon as a non-canonical scalar field is non-minimally coupled to gravity in the framework of teleparallel gravity. The explicit form of potential and coupling functions are obtained under the assumption that the Lagrangian admits the Noether symmetry approach. The dynamical behavior of the basic cosmological observables is compared to recent observational data, which implies that the tachyon field may serve as a candidate for dark energy.

  15. Dark energy cosmology with tachyon field in teleparallel gravity

    NASA Astrophysics Data System (ADS)

    Motavalli, H.; Akbarieh, A. Rezaei; Nasiry, M.

    2016-07-01

    We construct a tachyon teleparallel dark energy model for a homogeneous and isotropic flat universe in which a tachyon as a non-canonical scalar field is non-minimally coupled to gravity in the framework of teleparallel gravity. The explicit form of potential and coupling functions are obtained under the assumption that the Lagrangian admits the Noether symmetry approach. The dynamical behavior of the basic cosmological observables is compared to recent observational data, which implies that the tachyon field may serve as a candidate for dark energy.

  16. TALC: a new deployable concept for a 20m far-infrared space telescope

    NASA Astrophysics Data System (ADS)

    Durand, Gilles; Sauvage, Marc; Bonnet, Aymeric; Rodriguez, Louis; Ronayette, Samuel; Chanial, Pierre; Scola, Loris; Révéret, Vincent; Aussel, Hervé; Carty, Michael; Durand, Matthis; Durand, Lancelot; Tremblin, Pascal; Pantin, Eric; Berthe, Michel; Martignac, Jérôme; Motte, Frédérique; Talvard, Michel; Minier, Vincent; Bultel, Pascal

    2014-08-01

    TALC, Thin Aperture Light Collector is a 20 m space observatory project exploring some unconventional optical solutions (between the single dish and the interferometer) allowing the resolving power of a classical 27 m telescope. With TALC, the principle is to remove the central part of the prime mirror dish, cut the remaining ring into 24 sectors and store them on top of one-another. The aim of this far infrared telescope is to explore the 600 μm to 100 μm region. With this approach we have shown that we can store a ring-telescope of outer diameter 20m and ring thickness of 3m inside the fairing of Ariane 5 or Ariane 6. The general structure is the one of a bicycle wheel, whereas the inner sides of the segments are in compression to each other and play the rule of a rim. The segments are linked to each other using a pantograph scissor system that let the segments extend from a pile of dishes to a parabolic ring keeping high stiffness at all time during the deployment. The inner corners of the segments are linked to a central axis using spokes as in a bicycle wheel. The secondary mirror and the instrument box are built as a solid unit fixed at the extremity of the main axis. The tensegrity analysis of this structure shows a very high stiffness to mass ratio, resulting into 3 Hz Eigen frequency. The segments will consist of two composite skins and honeycomb CFRP structure build by replica process. Solid segments will be compared to deformable segments using the controlled shear of the rear surface. The adjustment of the length of the spikes and the relative position of the side of neighbor segments let control the phasing of the entire primary mirror. The telescope is cooled by natural radiation. It is protected from sun radiation by a large inflatable solar screen, loosely linked to the telescope. The orientation is performed by inertia-wheels. This telescope carries a wide field bolometer camera using cryocooler at 0.3K as one of the main instruments. This

  17. Unified dark energy and dark matter from a scalar field different from quintessence

    SciTech Connect

    Gao Changjun; Kunz, Martin; Liddle, Andrew R.; Parkinson, David

    2010-02-15

    We explore unification of dark matter and dark energy in a theory containing a scalar field of non-Lagrangian type, obtained by direct insertion of a kinetic term into the energy-momentum tensor. This scalar is different from quintessence, having an equation of state between -1 and 0 and a zero sound speed in its rest frame. We solve the equations of motion for an exponential potential via a rewriting as an autonomous system, and demonstrate the observational viability of the scenario, for sufficiently small exponential potential parameter {lambda}, by comparison to a compilation of kinematical cosmological data.

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

    SciTech Connect

    Yordanov, P.; Boris, A. V.; Freeland, J. W.; Kavich, J. J.; Chakhalian, J.; Lee, Ho Nyung; Keimer, Bernhard

    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.

  19. Quantum Dynamics of Dark and Dark-Bright Solitons beyond the Mean-Field Approximation

    NASA Astrophysics Data System (ADS)

    Krönke, Sven; Schmelcher, Peter

    2014-05-01

    Dark solitons are well-known excitations in one-dimensional repulsively interacting Bose-Einstein condensates, which feature a characteristical phase-jump across a density dip and form stability in the course of their dynamics. While these objects are stable within the celebrated Gross-Pitaevskii mean-field theory, the situation changes dramatically in the full many-body description: The condensate being initially in a dark soliton state dynamically depletes and the density notch fills up with depleted atoms. We analyze this process in detail with a particular focus on two-body correlations and the fate of grey solitons (dark solitons with finite density in the notch) and thereby complement the existing results in the literature. Moreover, we extend these studies to mixtures of two repulsively interacting bosonic species with a dark-bright soliton (dark soliton in one component filled with localized atoms of the other component) as the initial state. All these many-body quantum dynamics simulations are carried out with the recently developed multi-layer multi-configuration time-dependent Hartree method for bosons (ML-MCTDHB).

  20. Radiometric performances of the Fourier transform spectrometer for the Radiation Explorer in the Far-Infrared (REFIR) space mission

    NASA Astrophysics Data System (ADS)

    Palchetti, Luca; Bianchini, Giovanni; Pellegrini, Marco; Esposito, Francesco; Restieri, Rosa; Pavese, Giulia

    2004-11-01

    In the framework of the Radiation Explorer in the Far InfraRed space mission for the characterization in the far infrared of the Earth outgoing emission, a breadboard version of the Fourier transform spectrometer, which is the core instrument of the payload package, has been developed. The Fourier transform spectrometer operates in the spectral range of 100-1100 cm-1 with a resolution of 0.5 cm-1, 6.5 s acquisition time, and signal-to-noise ratio better than 100. It is a compact prototype designed both for laboratory applications and for field campaigns, in particular for operations in high-altitude ground-based sites and on-board of stratospheric balloon platforms. This paper describes the instrument characterization performed in laboratory conditions and under vacuum. The study has allowed to study the trade-off among all the instrument parameters and to test the new optical design of the interferometer, with particular attention to the photolithographic beam splitters and the room-temperature pyroelectric detectors. The instrument was operated for the first time in a field campaign in June 2004 from 1247~m altitude ground-based site located in the South of Italy. The results of this test and the comparison with the measurements taken with a BOMEM spectrometer, that partially overlaps the REFIR bandwidth in the higher spectral region, are reported. Info can be found at http://radiation.ifac.cnr.it.

  1. REGIONAL VARIATIONS IN THE DENSE GAS HEATING AND COOLING IN M51 FROM HERSCHEL FAR-INFRARED SPECTROSCOPY

    SciTech Connect

    Parkin, T. J.; Wilson, C. D.; Schirm, M. R. P.; Foyle, K.; Baes, M.; De Looze, I.; Boquien, M.; Boselli, A.; Cooray, A.; Cormier, D.; Karczewski, O. Ł.; Lebouteiller, V.; Madden, S. C.; Sauvage, M.; Spinoglio, L.

    2013-10-20

    We present Herschel PACS and SPIRE spectroscopy of the most important far-infrared cooling lines in M51, [C II](158 μm), [N II](122 and 205 μm), [O I](63 and 145 μm), and [O III](88 μm). 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 (FUV) radiation field, G{sub 0}, resolving details on physical scales of roughly 600 pc. We find an average [C II]/F{sub TIR} of 4 × 10{sup –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 FUV radiation field, G{sub 0}, and the hydrogen density, n, peaking in the nucleus of the galaxy, and 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 properties of the molecular clouds in both regions are essentially the same.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Optical characterisation and analysis of multi-mode pixels for use in future far infrared telescopes

    NASA Astrophysics Data System (ADS)

    McCarthy, Darragh; Trappe, Neil; Murphy, J. Anthony; Doherty, Stephen; Gradziel, Marcin; O'Sullivan, Créidhe; Audley, Michael D.; de Lange, Gert; van der Vorst, Maarten

    2016-07-01

    In this paper we present the development and verification of feed horn simulation code based on the mode- matching technique to simulate the electromagnetic performance of waveguide based structures of rectangular cross-section. This code is required to model multi-mode pyramidal horns which may be required for future far infrared (far IR) space missions where wavelengths in the range of 30 to 200 µm will be analysed. Multi-mode pyramidal horns can be used effectively to couple radiation to sensitive superconducting devices like Kinetic Inductance Detectors (KIDs) or Transition Edge Sensor (TES) detectors. These detectors could be placed in integrating cavities (to further increase the efficiency) with an absorbing layer used to couple to the radiation. The developed code is capable of modelling each of these elements, and so will allow full optical characterisation of such pixels and allow an optical efficiency to be calculated effectively. As the signals being measured at these short wavelengths are at an extremely low level, the throughput of the system must be maximised and so multi-mode systems are proposed. To this end, the focal planes of future far IR missions may consist of an array of multi-mode rectangular feed horns feeding an array of, for example, TES devices contained in individual integrating cavities. Such TES arrays have been fabricated by SRON Groningen and are currently undergoing comprehensive optical, electrical and thermal verification. In order to fully understand and validate the optical performance of the receiver system, it is necessary to develop comprehensive and robust optical models in parallel. We outline the development and verification of this optical modelling software by means of applying it to a representative multi-mode system operating at 150 GHz in order to obtain sufficiently short execution times so as to comprehensively test the code. SAFARI (SPICA FAR infrared Instrument) is a far infrared imaging grating spectrometer

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

    NASA Astrophysics Data System (ADS)

    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

  5. Study of BL Lac objects in far infrared and submillimetre region

    NASA Astrophysics Data System (ADS)

    Seal Braun, P.

    2017-07-01

    Here 35 BL Lac objects are studied from far infrared to submillimetre region (60 μm-850 μm) using the observational data from IRAS, ISO and SCUBA. Twelve Fanaroff-Riley radio galaxies are also studied for comparison. Using the flux densities at the far infrared and submillimetre bands, the luminosities, dust temperatures and dust masses are estimated. Total infrared luminosities L_{TIR} (8-1000 μm) (L_{⊙}) are derived from total flux densities (F_{8{-}1000}). The flux ratios at 100/60 vs. 170/100 plane show almost no correlation whereas the flux ratios at 60/850 vs. 100/850 plane show good correlation. About 50% of these sources show high F_{170} /F_{100} flux ratios indicating the presence of cold dust. Dust temperatures estimated from far infrared flux densities (F_{60} / F_{100}), vary from 25 K to 50 K, considering emissivity β = 1.5. The variation of dust temperature with total infrared luminosities L_{TIR} (L_{⊙}) shows good correlation whereas the variation of flux densities at 850 μm with total infrared luminosities L_{TIR} (L_{⊙}) shows weak correlation. The submillimetre luminosities at 850 μm (L_{850 } (L_{⊙})) and cold dust masses at 850 μm (Md) are estimated using the flux densities at 850 μm. The variation of the cold dust masses at 850 μm (Md (M0)) with submillimetre luminosities (L_{850 } (L_{⊙})) shows very good correlation. The submillimetre flux densities of BL Lac objects are much higher than the flux densities of radio galaxies or quasars but comparable to those of FR I radio galaxies. So the total IR luminosities (L_{TIR} (L_{⊙})), Luminosity at 850 μm (L_{850} (L_{⊙})) and cold dust mass (Md (M0)) of FR I radio galaxies are compared with the BL Lac objects. It is possible to compare the molecular gas mass M_{H2} with cold dust mass (Md) for only one BL Lac object W Com, due to unavailability of proper observational data.

  6. International Conference on Millimeter Wave and Far-Infrared Technology (1st) Held in Beijing, China, August 17-21, 1992

    DTIC Science & Technology

    1993-03-01

    Speci aP PUBLISHING HOUSE OF ELECTRONICS INDUSTRY rS Sponored By International Conference on Millimeter Wave and CIE Far-infrared Technology l August 17...support from many Industrial institutions such as Nanjing Semiconductor Research Institute,Beijing Electron Tube plant and 14th Radio Plant of Shanghai...Vacuum Technology, John Wiley & Sons, (1980)9 7. F. 3. Liao.Acta Electronica Sinica (In Chineoe)19(3)(1991)89 8. Guang-Yi Liu. 34th International Field

  7. Accurate determination of the fine-structure intervals in the 3P ground states of C-13 and C-12 by far-infrared laser magnetic resonance

    NASA Technical Reports Server (NTRS)

    Cooksy, A. L.; Saykally, R. J.; Brown, J. M.; Evenson, K. M.

    1986-01-01

    Accurate values are presented for the fine-structure intervals in the 3P ground state of neutral atomic C-12 and C-13 as obtained from laser magnetic resonance spectroscopy. The rigorous analysis of C-13 hyperfine structure, the measurement of resonant fields for C-12 transitions at several additional far-infrared laser frequencies, and the increased precision of the C-12 measurements, permit significant improvement in the evaluation of these energies relative to earlier work. These results will expedite the direct and precise measurement of these transitions in interstellar sources and should assist in the determination of the interstellar C-12/C-13 abundance ratio.

  8. Sensitivity of Atom Interferometry to Ultralight Scalar Field Dark Matter.

    PubMed

    Geraci, Andrew A; Derevianko, Andrei

    2016-12-23

    We discuss the use of atom interferometry as a tool to search for dark matter (DM) composed of virialized ultralight fields (VULFs). Previous work on VULF DM detection using accelerometers has considered the possibility of equivalence-principle-violating effects whereby gradients in the dark matter field can directly produce relative accelerations between media of differing composition. In atom interferometers, we find that time-varying phase signals induced by coherent oscillations of DM fields can also arise due to changes in the atom rest mass that can occur between light pulses throughout the interferometer sequence as well as changes in Earth's gravitational field. We estimate that several orders of magnitude of unexplored phase space for VULF DM couplings can be probed due to these new effects.

  9. Sensitivity of Atom Interferometry to Ultralight Scalar Field Dark Matter

    NASA Astrophysics Data System (ADS)

    Geraci, Andrew A.; Derevianko, Andrei

    2016-12-01

    We discuss the use of atom interferometry as a tool to search for dark matter (DM) composed of virialized ultralight fields (VULFs). Previous work on VULF DM detection using accelerometers has considered the possibility of equivalence-principle-violating effects whereby gradients in the dark matter field can directly produce relative accelerations between media of differing composition. In atom interferometers, we find that time-varying phase signals induced by coherent oscillations of DM fields can also arise due to changes in the atom rest mass that can occur between light pulses throughout the interferometer sequence as well as changes in Earth's gravitational field. We estimate that several orders of magnitude of unexplored phase space for VULF DM couplings can be probed due to these new effects.

  10. Coincidence problem in YM field dark energy model

    NASA Astrophysics Data System (ADS)

    Zhao, Wen; Zhang, Yang

    2006-09-01

    The coincidence problem is studied in the effective Yang Mills condensate dark energy model. As the effective YM Lagrangian is completely determined by quantum field theory, there is no adjustable parameter in this model except the energy scale, and the cosmic evolution only depends on the initial conditions. For generic initial conditions with the YM condensate subdominant to the radiation and matter, the model always has a tracking solution, the Universe transits from matter-dominated into the dark energy dominated stage only recently z˜0.3, and evolve to the present state with Ω˜0.73 and Ω˜0.27.

  11. Search for Kilonovae in Dark Energy Survey Supernova Fields

    NASA Astrophysics Data System (ADS)

    Doctor, Zoheyr; DES-GW Team; DES-SN Team

    2016-03-01

    The Dark Energy Camera on the Blanco 4-m Telescope is an ideal instrument for identifying rapid optical transients with its large field of view and four optical filters. We utilize two seasons of data from the Dark Energy Survey to search for kilonovae, an optical counterpart to gravitational waves from binary neutron star mergers. Kilonova lightcurves from Barnes and Kasen inform our analysis for removing background signals such as supernovae. We simulate DES observations of kilonovae with the SNANA software package to estimate our search efficiency and optimize cuts. Finally, we report rate limits for binary neutron star mergers and compare to existing rate estimates.

  12. Dark matter deprivation in the field elliptical galaxy NGC 7507

    NASA Astrophysics Data System (ADS)

    Lane, Richard R.; Salinas, Ricardo; Richtler, Tom

    2015-02-01

    Context. Previous studies have shown that the kinematics of the field elliptical galaxy NGC 7507 do not necessarily require dark matter. This is troubling because, in the context of ΛCDM cosmologies, all galaxies should have a large dark matter component. Aims: Our aims are to determine the rotation and velocity dispersion profile out to larger radii than do previous studies, and, therefore, more accurately estimate of the dark matter content of the galaxy. Methods: We use penalised pixel-fitting software to extract velocities and velocity dispersions from GMOS slit mask spectra. Using Jeans and MONDian modelling, we then produce models with the goal of fitting the velocity dispersion data. Results: NGC 7507 has a two-component stellar halo, with the outer halo counter rotating with respect to the inner halo, with a kinematic boundary at a radius of ~110'' (~12.4 kpc). The velocity dispersion profile exhibits an increase at ~70'' (~7.9 kpc), reminiscent of several other elliptical galaxies. Our best fit models are those under mild anisotropy, which include ~100 times less dark matter than predicted by ΛCDM, although mildly anisotropic models that are completely dark matter free fit the measured dynamics almost equally well. Our MONDian models, both isotropic and anisotropic, systematically fail to reproduce the measured velocity dispersions at almost all radii. Conclusions: The counter-rotating outer halo implies a merger remnant, as does the increase in velocity dispersion at ~70''. From simulations it seems plausible that the merger that caused the increase in velocity dispersion was a spiral-spiral merger. Our Jeans models are completely consistent with a no dark matter scenario, however, some dark matter can be accommodated, although at much lower concentrations than predicted by ΛCDM simulations. This indicates that NGC 7507 may be a dark matter free elliptical galaxy. Regardless of whether NGC 7507 is completely dark matter free or very dark matter poor

  13. Far-infrared image restoration analysis of the protostellar cluster in S140

    NASA Technical Reports Server (NTRS)

    Lester, D. F.; Harvey, P. M.; Joy, M.; Ellis, H. B., Jr.

    1986-01-01

    Image restoration techniques are applied to one-dimensional scans at 50 and 100 microns of the protostellar cluster in S140. These measurements resolve the surrounding nebula clearly, and Fourier methods are used to match the effective beam profiles at these wavelengths. This allows the radial distribution of temperature and dust column density to be derived at a diffraction limited spatial resolution of 23 arcsec (0.1 pc). Evidence for heating of the S140 molecular cloud by a nearby ionization front is established, and the dissociation of molecules inside the ionization front is spatially well correlated with the heating of the dust. The far-infrared spectral distribution of the three near-infrared sources within 10 arcsesc of the cluster center is presented.

  14. Segment-based region of interest generation for pedestrian detection in far-infrared images

    NASA Astrophysics Data System (ADS)

    Kim, D. S.; Lee, K. H.

    2013-11-01

    We present a region of interest (ROI) generation method specialized for nighttime pedestrian detection using far-infrared (FIR) images. Because pedestrians typically appear brighter than background in FIR images, previous research efforts primarily attempted to extract ROIs based on the intensity threshold. However this approach has problems resulting from the intensity variances of pedestrians due to their clothing and, especially in urban scenarios, and other heat sources that emit more heat than the pedestrians. In this paper, we propose a novel ROI generation method that is based on combining image segments instead of using the intensity threshold. In order to minimize dependence on brightness, we utilize the low-frequency characteristics of FIR images. As a result, our proposed method generates a small number of ROIs at an acceptable miss rate and the generated ROIs provide advantages for classification because the pedestrians are satisfactorily arranged within a bounding box. Experiments conducted indicate that our proposed method performs reliably in urban scenarios.

  15. Stratospheric minor constituent distributions from far-infrared thermal emission spectra

    NASA Technical Reports Server (NTRS)

    Abbas, Mian M.; Traub, Wesley A.

    1992-01-01

    We retrieve mixing ratio profiles of O3, H2(O-16), H2(O-17), H2(O-18), HF, and HCl from far-infrared thermal emission observations of the limb in the 80-220 cm/sec spectral region. The observations were made with a balloon-borne Fourier transform spectrometer as a part of the 1983 Balloon Intercomparison Campaign (BIC-2). A subset of the data was analyzed previously using the method in the work of Traub et al. (1982, 1991); in the present paper we use an alternative method of calibration and analysis, given by Abbas et al. (1985). The retrieved constituent profiles are compared with the measurements made with other instruments on the BIC-2 flights. The results for the concentrations of H2(O-17) and H2(O-18) obtained in this study indicate no isotopic enhancement or depletion with a standard deviation of about 20 percent.

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

    NASA Technical Reports Server (NTRS)

    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.

  17. Space-exposure effects on optical-baffle coatings at far-infrared wavelengths

    NASA Technical Reports Server (NTRS)

    Blue, M. D.; Perkowitz, S.

    1992-01-01

    Reflectance of six optical-black coatings was remeasured over the near-infrared to the far-infrared region after nearly six years in space aboard the Long Duration Exposure Facility satellite. Measurements were made at room temperature and at cryogenic temperatures. The most notable effect was a general decrease in reflectance for typical samples at all wavelengths. Analysis indicates that this decrease is caused by an increase in absorption resulting from an increase in the imaginary part of the index of refraction, and not by a change in thickness, or increased surface roughness giving rise to increased scattering. These results suggest that such optical-baffle materials will provide enhanced performance as a result of aging in the space environment.

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

    NASA Technical Reports Server (NTRS)

    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.

  19. Determination of the Far-Infrared Cosmic Background Using COBE/DIRBE and WHAM Data

    NASA Technical Reports Server (NTRS)

    Odegard, N.; Arendt, R. G.; Dwek, E.; Haffner, L. M.; Hauser, M. G.; Reynolds, R. J.

    2007-01-01

    Determination of the cosmic infrared background (CIB) at far infrared wavelengths using COBE/DIRBE data is limited by the accuracy to which foreground interplanetary and Galactic dust emission can be modeled and subtracted. Previous determinations of the far infrared CIB (e.g., Hauser et al. 1998) were based on the detection of residual isotropic emission in skymaps from which the emission from interplanetary dust and the neutral interstellar medium were removed. In this paper we use the Wisconsin H(alpha) Mapper (WHAM) Northern Sky Survey as a tracer of the ionized medium to examine the effect of this foreground component on determination of the CIB. We decompose the DIRBE far infrared data for five high Galactic latitude regions into HI- and H(alpha)- correlated components and a residual component. Eased on FUSE H2 absorption line observations, the contribution of a11 H2-correlated component is expected to he negligible. We find the H(alpha)-correlated component to be consistent with zero for each region, and we find that addition of an H(alpha)-correlated component in modeling the foreground emission has negligible effect on derived CIB results. Our CIB detections and 2(sigma) upper limits are essentially the same as those derived by Hauser et al. and are given by (nu)I(sub nu)(nW/sq m/sr) < 75, < 32, 25+/-8, and 13+/-3 at gamma = 60, 100, 140, and 240 microns, respectively. Our residuals have not been subjected to a detailed anisotropy test, so our CIB results do not supersede those of Hauser et al. Mie derive upper limits on the 100 micron emissivity of the ionized medium that are typically about 40% of the 100 micron emissivity of the neutral atomic medium. This low value may be caused in part by a lower dust-to-gas mass ratio in the ionized medium than in the neutral medium, and in part by a shortcoming of using H(alpha) intensity as a tracer of far infrared emission. If H(alpha) is not a reliable tracer, our analysis would underestimate the emissivity of

  20. Stratospheric minor constituent distributions from far-infrared thermal emission spectra

    NASA Astrophysics Data System (ADS)

    Abbas, Mian M.; Traub, Wesley A.

    1992-11-01

    We retrieve mixing ratio profiles of O3, H2(O-16), H2(O-17), H2(O-18), HF, and HCl from far-infrared thermal emission observations of the limb in the 80-220 cm/sec spectral region. The observations were made with a balloon-borne Fourier transform spectrometer as a part of the 1983 Balloon Intercomparison Campaign (BIC-2). A subset of the data was analyzed previously using the method in the work of Traub et al. (1982, 1991); in the present paper we use an alternative method of calibration and analysis, given by Abbas et al. (1985). The retrieved constituent profiles are compared with the measurements made with other instruments on the BIC-2 flights. The results for the concentrations of H2(O-17) and H2(O-18) obtained in this study indicate no isotopic enhancement or depletion with a standard deviation of about 20 percent.

  1. Hydration-dependent far-infrared absorption in lysozyme detected using synchrotron radiation.

    PubMed Central

    Moeller, K D; Williams, G P; Steinhauser, S; Hirschmugl, C; Smith, J C

    1992-01-01

    Using the National Synchrotron Light Source (NSLS) at Brookhaven far-infrared absorption in the frequency range 15-45 cm-1 was detected in samples of lysozyme at different hydrations and in water. The absorption is due to the presence of low-frequency (picosecond timescale) motion in the samples, such as are calculated in molecular dynamics simulations. The form of the transmission profile is temperature independent but varies significantly with the degree of hydration of the protein. At higher hydrations the profile resembles closely that of pure water in the region 20-45 cm-1. At a low hydration marked differences are seen with, in particular, the appearance of a transmission minimum at 19 cm-1. The possible origins of the hydration dependence are discussed. The results demonstrate the usefulness of long-wavelength synchrotron radiation for the characterisation of biologically-important low-frequency motions in protein samples. PMID:1540696

  2. Mid-infrared versus far-infrared (THz) relative intensities of room-temperature Bacillus spores

    NASA Astrophysics Data System (ADS)

    Johnson, Timothy J.; Valentine, Nancy B.; Sharpe, Steven W.

    2005-02-01

    We have simultaneously recorded the mid-IR and far-IR (a.k.a. terahertz, THz) spectra of the sporulated form of five Bacillus bacteria: Bacillus subtilis ATCC 49760, B. subtilis ATCC 6051, Bacillus thuringiensis subsp. kurstaki ATCC 35866, Bacillus globigii 01, and Bacillus atrophaeus 49337. The 295 K spectra were recorded from ˜8 to 6000 cm -1 using spore counts on the order of 10 9 deposited onto windows transparent in both the mid- and far-infrared. The results indicate that any room-temperature THz absorption features due to the spores are at least 28 times weaker (based on p-p noise) than the corresponding mid-IR amide I band.

  3. Probing Dirac electron transport in graphene by far-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Shan, Jie; He, Keliang; Zhao, Liang; Mak, Kin Fai; Petrone, Nick; Hone, Jim; Heinz, Tony

    2012-02-01

    The transport properties of Dirac fermions in graphene are a subject of intense interest. While various scattering mechanisms including impurities, graphene phonons and substrate phonons have been examined by dc transport measurements,ootnotetextDas Sarma, S., Adam, S., Hwang, E. H. & Rossi, E. Rev. Mod. Phys. 83, 407-470, (2011). direct determination of the scattering rates under different experimental conditions remains challenging.ootnotetextHorng, J. et al. Phys. Rev. B 83, 165113, (2011). In this paper we report on the far-infrared optical conductivity spectrum of monolayer graphene samples obtained by Fourier transform infrared spectroscopy. From the frequency dependence of the optical conductivity we determine both the Drude weight and the carrier scattering rate. The dependence of these transport parameters on temperature and electrostatic doping will be presented, and the importance of many-body Coulomb interactions between Dirac electrons will be discussed.

  4. Measurement of the stratospheric hydrogen peroxide concentration profile using far infrared thermal emission spectroscopy

    NASA Technical Reports Server (NTRS)

    Chance, K. V.; Johnson, D. G.; Traub, W. A.; Jucks, K. W.

    1991-01-01

    The first unequivocal measurement of hydrogen peroxide in the stratosphere have been made, a concentration profile obtained from a balloon platform using Fourier transform thermal emission spectroscopy in the far infrared. Measurements were made using the 112/cm R-Q5 branch of the rotational-torsional spectrum, with some confirmation from the 94/cm R-Q4 branch. The volume mixing ratio of H2O2 is 1.6 x 10 to the -10th at 38.4 km, decreasing to 0.6 x 10 to the -10th at 23.8 km, with uncertainties of about 16 percent. These measurements are compared to a recent stratospheric model calculation.

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

    NASA Technical Reports Server (NTRS)

    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.

  6. Effects of particle size on far infrared emission properties of tourmaline superfine powders.

    PubMed

    Meng, Junping; Jin, Wei; Liang, Jinsheng; Ding, Yan; Gan, Kun; Yuan, Youde

    2010-03-01

    Tourmaline superfine powders with different particle sizes were prepared by grinding, superfine ball milling, and high-speed centrifugation. The powders were characterized by scanning electron microscopy, X-ray diffraction, dynamic contact angle meter and tensiometry, and Fourier transform infrared spectrometry. The results show that tourmaline powders exhibit improved far infrared emission properties as the particle size decreases. The increased surface free energy and proportion of the polar component are considered to play an important role for their properties. The spontaneous polarization is increased, and the dipole moment of tourmaline is stimulated to a high energy level more easily for the chemical bond vibration, so that the energy is apt to emit by transition. In the range of 2000-500 cm(-1), the emissivity values of the samples with D50 size of 2.67 microm and 0.2 microm are 0.973 and 0.991, respectively.

  7. Far Infrared Line Profiles from Photodissociation Regions and Warm Molecular Clouds

    NASA Technical Reports Server (NTRS)

    Boreiko, R. T.; Betz, A. L.

    1998-01-01

    This report summarizes the work done under NASA Grant NAG2-1056 awarded to the University of Colorado. The aim of the project was to analyze data obtained over the past several years with the University of Colorado far-infrared heterodyne spectrometer aboard the Kuiper Airborne Observatory. Of particular interest were observations of CO and ionized carbon (C II) in photodissociation regions (PDRS) at the interface between UV-ionized H II regions and the neutral molecular clouds supporting star formation. These data, obtained with a heterodyne spectrometer having a resolution of 3.2 MHz, which is equivalent to a velocity resolution of 0.2 km s(exp -1) at 60 microns and 1.0 km s(exp -1) at 300 microns, were analyzed to obtain physical parameters such as density and temperature in the observed PDR.

  8. Vibration mitigation in J-TEXT far-infrared diagnostic systems

    SciTech Connect

    Li, Q.; Chen, J.; Zhuang, G.; Wang, Z. J.; Gao, L.; Chen, W.

    2012-10-15

    Optical structure stability is an important issue for far-infrared (FIR) phase measurements. To ensure good signal quality, influence of vibration should be minimized. Mechanical amelioration and optical optimization can be taken in turn to decrease vibration's influence and ensure acceptable measurement. J-TEXT (Joint Texal Experiment Tokamak, formerly TEXT-U) has two FIR diagnostic systems: a HCN interferometer system for electron density measurement and a three-wave polarimeter-interferometer system (POLARIS) for electron density and Faraday effect measurements. All use phase detection techniques. HCN interferometer system has almost eliminated the influence of vibration after mechanical amelioration and optical optimization. POLARIS also obtained first experimental results after mechanical stability improvements and is expected to further reduce vibration's influence on Faraday angle to 0.1 Degree-Sign after optical optimization.

  9. Far-Infrared Line Mapper (FILM) on the Infrared Telescope in Space

    NASA Astrophysics Data System (ADS)

    Shibai, Hiroshi; Yui, Masao; Matsuhara, Hideo; Hiromoto, Norihisa; Nakagawa, Takao; Okuda, Haruyuki

    1994-06-01

    We have developed a Far-Infrared Line Mapper (FILM) as one of the four focal plane instruments on the Infrared Telescope in Space (IRTS). The FILM is a grating spectrometer designed to simultaneously measure (C II) 158 microns and (O I) 63 microns line intensities and continuum emission near the (C II) line with spatial resolution of 8 arcmin. Very high sensitivity and accuracy are achieved by using stressed and unstressed Ge: Ga detectors at 1.8 K with a helium cooled telescope and by using a spectral scanner to distinguish the line emission from the continuum emission. Line intensities of the (C II) and the (O I) will be mapped over 10% of the sky with much higher sensitivity than the previous survey measurements.

  10. Dichroic filters to protect milliwatt far-infrared detectors from megawatt ECRH radiation.

    PubMed

    Bertschinger, G; Endres, C P; Lewen, F; Oosterbeek, J W

    2008-10-01

    Dichroic filters have been used to shield effectively the far infrared (FIR) detectors at the interferometer/polarimeter on TEXTOR. The filters consist of metal foils with regular holes, the hole diameter, the mutual spacing and the thickness of the foils are chosen to transmit radiation at the design frequency with transmission >90%. The attenuation at the low frequency end of the bandpass filter is about 30 dB per octave, the high frequency transmission is between 20% and 40%. The filters have been used to block the stray radiation from the megawatt microwave heating beam to the detectors of the FIR interferometer, operating with power on the detector in the milliwatt range. If required, the low frequency attenuation can be still enhanced, without compromising the transmission in the passband. The FIR interferometer used for plasma density and position control is no longer disturbed by electromagnetic waves used for plasma heating.

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

    NASA Astrophysics Data System (ADS)

    Wu, Hao-Yi; Doré, Olivier

    2017-01-01

    Cosmic far-infrared background (CFIRB) probes unresolved dusty star-forming galaxies across cosmic time and is complementary to ultraviolet and optical observations of galaxy evolution. In this work, we interpret the observed CFIRB anisotropies using an empirical model based on resolved galaxies in ultraviolet and optical surveys. Our model includes stellar mass functions, star-forming main sequence, and dust attenuation. We find that the commonly used linear Kennicutt relation between infrared luminosity and star-formation rate over-produces the observed CFIRB amplitudes. The observed CFIRB requires that low-mass galaxies have lower infrared luminosities than expected from the Kennicutt relation, implying that low-mass galaxies have lower dust content and weaker dust attenuation. Our results demonstrates that CFIRB not only provides a stringent consistency check for galaxy evolution models but also constrains the dust content of low-mass galaxies.

  12. A new, compact far-infrared source in the W31 region

    NASA Technical Reports Server (NTRS)

    Fazio, G. G.; Lada, C. J.; Kleinmann, D. E.; Wright, E. L.; Ho, P. T. P.; Low, F. J.

    1978-01-01

    In a survey of the W31 region, a compact far-infrared source was detected at the position of the radio continuum source G 10.6-0.4. Associated with this infrared source and in close coincidence with its position is an H II region with a compact core and extended halo as well as OH and H2O masers. An extended molecular cloud, centered on these sources, has also been detected. The compact source and associated masers may be located at the H II region-molecular-cloud interface in a thin shocked layer of neutral gas driven into the molecular cloud by the expansion of the H II region. The compact H II region is depleted of dust and must be surrounded by a very dense shell of dust and gas (hydrogen number density in excess of 200,000 per cu cm). The source probably represents an early stage of stellar evolution.

  13. FIFI: The MPE Garching/UC Berkeley Far-Infrared Imaging Fabry-Perot Interferometer

    NASA Technical Reports Server (NTRS)

    Geis, Norbert; Genzel, Reinhard; Haggerty, M.; Herrmann, F.; Jackson, J.; Madden, Suzanne C.; Nikola, T.; Poglitsch, Albrecht; Rumitz, M.; Stacey, G. J.

    1995-01-01

    We describe the performance characteristics of the MPE Garching/UC Berkeley Far-Infrared Imaging Fabry-Perot Interferometer (FIFI) for the Kuiper Airborne Observatory (KAO). The spectrometer features two or three cryogenic tunable Fabry-Perot filters in series giving spectral resolution R of up to 10(exp 5) in the range of 40 microns less than lambda less than 200 microns, and an imaging 5x5 array of photoconductive detectors with variable focal plane plate scale. The instrument works at background limited sensitivity of up to 2 x 10(exp -19) W cm(exp -2) Hz(exp -1/2) per pixel per resolution element at R = 10(exp 5) on the KAO.

  14. Optics alignment of a balloon-borne far-infrared interferometer BETTII

    NASA Astrophysics Data System (ADS)

    Dhabal, Arnab; Rinehart, Stephen A.; Rizzo, Maxime J.; Mundy, Lee; Sampler, Henry; Juanola-Parramon, Roser; Veach, Todd; Fixsen, Dale; de Lorenzo, Jordi Vila Hernandez; Silverberg, Robert F.

    2017-04-01

    The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-m baseline far-infrared (FIR: 30-90 μm) interferometer providing spatially resolved spectroscopy. The initial scientific focus of BETTII is on clustered star formation, but this capability likely has a much broader scientific application. One critical step in developing an interferometer, such as BETTII, is the optical alignment of the system. We discuss how we determine alignment sensitivities of different optical elements on the interferogram outputs. Accordingly, an alignment plan is executed that makes use of a laser tracker and theodolites for precise optical metrology of both the large external optics and the small optics inside the cryostat. We test our alignment on the ground by pointing BETTII to bright near-infrared sources and obtaining their images in the tracking detectors.

  15. FIFI: The MPE Garching/UC Berkeley Far-Infrared Imaging Fabry-Perot Interferometer

    NASA Technical Reports Server (NTRS)

    Geis, Norbert; Genzel, Reinhard; Haggerty, M.; Herrmann, F.; Jackson, J.; Madden, Suzanne C.; Nikola, T.; Poglitsch, Albrecht; Rumitz, M.; Stacey, G. J.

    1995-01-01

    We describe the performance characteristics of the MPE Garching/UC Berkeley Far-Infrared Imaging Fabry-Perot Interferometer (FIFI) for the Kuiper Airborne Observatory (KAO). The spectrometer features two or three cryogenic tunable Fabry-Perot filters in series giving spectral resolution R of up to 10(exp 5) in the range of 40 microns less than lambda less than 200 microns, and an imaging 5x5 array of photoconductive detectors with variable focal plane plate scale. The instrument works at background limited sensitivity of up to 2 x 10(exp -19) W cm(exp -2) Hz(exp -1/2) per pixel per resolution element at R = 10(exp 5) on the KAO.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  18. Vibration mitigation in J-TEXT far-infrared diagnostic systems.

    PubMed

    Li, Q; Chen, J; Zhuang, G; Wang, Z J; Gao, L; Chen, W

    2012-10-01

    Optical structure stability is an important issue for far-infrared (FIR) phase measurements. To ensure good signal quality, influence of vibration should be minimized. Mechanical amelioration and optical optimization can be taken in turn to decrease vibration's influence and ensure acceptable measurement. J-TEXT (Joint Texal Experiment Tokamak, formerly TEXT-U) has two FIR diagnostic systems: a HCN interferometer system for electron density measurement and a three-wave polarimeter-interferometer system (POLARIS) for electron density and Faraday effect measurements. All use phase detection techniques. HCN interferometer system has almost eliminated the influence of vibration after mechanical amelioration and optical optimization. POLARIS also obtained first experimental results after mechanical stability improvements and is expected to further reduce vibration's influence on Faraday angle to 0.1° after optical optimization.

  19. Vibration mitigation in J-TEXT far-infrared diagnostic systemsa)

    NASA Astrophysics Data System (ADS)

    Li, Q.; Chen, J.; Zhuang, G.; Wang, Z. J.; Gao, L.; Chen, W.

    2012-10-01

    Optical structure stability is an important issue for far-infrared (FIR) phase measurements. To ensure good signal quality, influence of vibration should be minimized. Mechanical amelioration and optical optimization can be taken in turn to decrease vibration's influence and ensure acceptable measurement. J-TEXT (Joint Texal Experiment Tokamak, formerly TEXT-U) has two FIR diagnostic systems: a HCN interferometer system for electron density measurement and a three-wave polarimeter-interferometer system (POLARIS) for electron density and Faraday effect measurements. All use phase detection techniques. HCN interferometer system has almost eliminated the influence of vibration after mechanical amelioration and optical optimization. POLARIS also obtained first experimental results after mechanical stability improvements and is expected to further reduce vibration's influence on Faraday angle to 0.1° after optical optimization.

  20. Space-exposure effects on optical-baffle coatings at far-infrared wavelengths

    NASA Technical Reports Server (NTRS)

    Blue, M. D.; Perkowitz, S.

    1992-01-01

    Reflectance of six optical-black coatings was remeasured over the near-infrared to the far-infrared region after nearly six years in space aboard the Long Duration Exposure Facility satellite. Measurements were made at room temperature and at cryogenic temperatures. The most notable effect was a general decrease in reflectance for typical samples at all wavelengths. Analysis indicates that this decrease is caused by an increase in absorption resulting from an increase in the imaginary part of the index of refraction, and not by a change in thickness, or increased surface roughness giving rise to increased scattering. These results suggest that such optical-baffle materials will provide enhanced performance as a result of aging in the space environment.

  1. Far infrared and near millimeter wave characterisation of samples in an international sample exchange

    NASA Astrophysics Data System (ADS)

    Simonis, G. J.; Stead, M.

    1991-10-01

    The instrument used to characterize the materials is a polarizing Fourier transform interferometer operating in free space. Atmospheric effects are not substantial over the operational frequency range (100 to 550 GHz) and the free space path lengths (meters) of these studies. The interferometer is composed of components mounted on an optical table. The source is a 100 W one atmosphere water cooled mercury arc lamp. The source is modulated at 75 Hz with an optical chopper in order to do synchronous detection processing with a lockin amplifier. The use of amplitude modulation rather than phase modulation minimizes the low frequency far infrared rolloff of the instrument function at the low millimeter wave frequencies where the available lamp power is very limited. The wire grating beam splitters also reduce the low frequency rolloff that would otherwise be introduced by the use of mylar beam splitters. A diagrammatic representation of the polarizing interferometer used is presented.

  2. Wavelength-independent anti-interference coating for the far-infrared

    NASA Technical Reports Server (NTRS)

    Mcknight, S. W.; Stewart, K. P.; Drew, H. D.; Moorjani, K.

    1987-01-01

    The transmission and reflection of radiation at an interface between two dielectrics with a thin conducting film is analyzed under conditions appropriate to the far-infrared. When the transmission is from a more dense to a less dense optical medium it is demonstrated that the reflectivity can be made arbitrarily small for a wide range of wavelengths by selecting the appropriate sheet resistance for the conducting film. This property can be exploited to produce a coating that drastically reduces the interference fringes in a flat plane-parallel dielectric substrate or window. The condition depends only on the film resistance which can be monitored precisely during deposition. This effect is demonstrated by evaporating films of nichrome on silicon substrates, which reduce the interference fringe contrast to less than 1 percent transmittance from 10-100/cm. Near the antiinterference condition the fringe contrast is shown to be a sensitive probe of the film conductivity.

  3. Optics Alignment of a Balloon-Borne Far-Infrared Interferometer BETTII

    NASA Technical Reports Server (NTRS)

    Dhabal, Arnab; Rinehart, Stephen A.; Rizzo, Maxime J.; Mundy, Lee; Sampler, Henry; Juanola Parramon, Roser; Veach, Todd; Fixsen, Dale; Vila Hernandez De Lorenzo, Jor; Silverberg, Robert F.

    2017-01-01

    The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-m baseline far-infrared (FIR: 30 90 micrometer) interferometer providing spatially resolved spectroscopy. The initial scientific focus of BETTII is on clustered star formation, but this capability likely has a much broader scientific application.One critical step in developing an interferometer, such as BETTII, is the optical alignment of the system. We discuss how we determine alignment sensitivities of different optical elements on the interferogram outputs. Accordingly, an alignment plan is executed that makes use of a laser tracker and theodolites for precise optical metrology of both the large external optics and the small optics inside the cryostat. We test our alignment on the ground by pointing BETTII to bright near-infrared sources and obtaining their images in the tracking detectors.

  4. On the Assignment of Optically Pumped Far-Infrared Laser Emission from CH 3OH

    NASA Astrophysics Data System (ADS)

    Lees, R. M.; Xu, Li-Hong

    1999-08-01

    Progress in the analysis of the infrared spectrum of CH3OH in the 930-1450 cm-1 region has led to assignments, confirmations, or new insights for a number of far-infrared laser (FIRL) transition systems optically pumped by CO2 lasers. Many of the systems involve FIRL transitions among the CO-stretching, CH3-rocking, OH-bending, and CH3-deformation vibrational modes, giving useful information on the torsion-rotation structure of the methanol vibrational energy manifold. Some anomalies and mysteries concerning the identity of the lasing levels have been resolved, but several new ones have arisen. Altogether, 45 CH3OH IR-pump/FIR-laser systems are examined in light of the new spectroscopic information; about half of the system assignments are new and half have been previously reported in the literature and are here confirmed, extended, or revised.

  5. Mid- and far-infrared spectroscopy of ices - Optical constants and integrated absorbances

    NASA Technical Reports Server (NTRS)

    Hudgins, D. M.; Sandford, S. A.; Allamandola, L. J.; Tielens, A. G. G. M.

    1993-01-01

    Laboratory spectra through the mid-infrared (4000 to 500/cm (2.5-20 microns) have been used to calculate the optical constants (n and k) and integrated absorption coefficients (A) for a variety of pure and mixed molecular ices of relevance to astrophysics. The ices studied were H2O, CH3OH, CO2, OCS, CH4, CO2 + CH4, CO2 + OCS, CO + CH4, CO + OCS, O2 + CH4, O2 + OCS, N2 + CH4, N2 + OCS, H2O + CH4, H2O + OCS, and H2O + CH3OH + CO + NH3. In addition, the measurements have been extended through the far-infrared (500 to 50/cm (20-200 microns) for the H2O, CH3OH, and H2O + CH3OH + CO + NH3 ices.

  6. Wavelength-independent anti-interference coating for the far-infrared

    NASA Technical Reports Server (NTRS)

    Mcknight, S. W.; Stewart, K. P.; Drew, H. D.; Moorjani, K.

    1987-01-01

    The transmission and reflection of radiation at an interface between two dielectrics with a thin conducting film is analyzed under conditions appropriate to the far-infrared. When the transmission is from a more dense to a less dense optical medium it is demonstrated that the reflectivity can be made arbitrarily small for a wide range of wavelengths by selecting the appropriate sheet resistance for the conducting film. This property can be exploited to produce a coating that drastically reduces the interference fringes in a flat plane-parallel dielectric substrate or window. The condition depends only on the film resistance which can be monitored precisely during deposition. This effect is demonstrated by evaporating films of nichrome on silicon substrates, which reduce the interference fringe contrast to less than 1 percent transmittance from 10-100/cm. Near the antiinterference condition the fringe contrast is shown to be a sensitive probe of the film conductivity.

  7. Specification and Design of the SBRC-190: A Cryogenic Multiplexer for Far Infrared Photoconductor Detectors

    NASA Technical Reports Server (NTRS)

    Erickson, E. F.; Young, E. T.; Wolf, J.; Asbrock, J. F.; Lum, N.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    Arrays of far-infrared photoconductor detectors operate at a few degrees Kelvin and require electronic amplifiers in close proximity. For the electronics, a cryogenic multiplexer is ideal to avoid the large number of wires associated with individual amplifiers for each pixel, and to avoid adverse effects of thermal and radiative heat loads from the circuitry. For low background applications, the 32 channel CRC 696 CMOS device was previously developed for SIRTF, the cryogenic Space Infrared Telescope Facility. For higher background applications, we have developed a similar circuit, featuring several modifications: (a) an AC coupled, capacitive feedback transimpedence unit cell, to minimize input offset effects, thereby enabling low detector biases, (b) selectable feedback capacitors to enable operation over a wide range of backgrounds, and (c) clamp and sample & hold output circuits to improve sampling efficiency, which is a concern at the high readout rates required. We describe the requirements for and design of the new device.

  8. Far-Infrared Hydrogen Lasers in the Peculiar Star MWC 349A

    NASA Technical Reports Server (NTRS)

    Strelnitski, Vladimir; Haas, Michael R.; Smith, Howard A.; Erickson, Edwin F.; Colgan, Sean W. J.; Hollenbach, David J.

    1996-01-01

    Far-infrared hydrogen recombination lines H15(alpha)(169.4 micrometers), H12(alpha)(88.8 micrometers), and H10(alpha)(52.5 micrometers) were detected in the peculiar luminous star MWC 349A from the Kuiper Airborne Observatory. Here it is shown that at least H15(alpha) is strongly amplified, with the probable amplification factor being greater than or about equal to 10(exp 3) and a brightness temperature that is greater than or about equal to 10(exp 7) kelvin. The other two lines also show signs of amplification, although to a lesser degree. Beyond H10(alpha) the amplification apparently vanishes. The newly detected amplified lines fall into the laser wavelength domain. These lasers, as well as the previously detected hydrogen masers may originate in the photoionized circumstellar disk of MWC 349A and constrain the disk's physics and structure.

  9. Balloon-borne three-meter telescope for far-infrared and submillimeter astronomy

    NASA Technical Reports Server (NTRS)

    Fazio, G. G.

    1985-01-01

    Presented are scientific objectives, engineering analysis and design, and results of technology development for a Three-Meter Balloon-Borne Far-Infrared and Submillimeter Telescope. The scientific rationale is based on two crucial instrumental capabilities: high angular resolution which approaches eight arcseconds at one hundred micron wavelength, and high resolving power spectroscopy with good sensitivity throughout the telescope's 30-micron to 1-mm wavelength range. The high angular resolution will allow us to resolve and study in detail such objects as collapsing protostellar condensations in our own galaxy, clusters of protostars in the Magellanic clouds, giant molecular clouds in nearby galaxies, and spiral arms in distant galaxies. The large aperture of the telescope will permit sensitive spectral line measurements of molecules, atoms, and ions, which can be used to probe the physical, chemical, and dynamical conditions in a wide variety of objects.

  10. Far-Infrared Study of BaTi4O9 Microwave Dielectric Ceramics

    NASA Astrophysics Data System (ADS)

    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.

  11. A variable reflectivity output coupler for optically pumped far infrared lasers

    NASA Astrophysics Data System (ADS)

    Graf, U. U.; Harris, A. I.; Stutzki, J.; Genzel, R.

    1992-06-01

    The design and performance of a variable reflectivity output coupler for optically pumped far infrared lasers are investigated. The output coupler is a compact, tunable Michelson interferometer. The output coupling ratio is adjustable between 0 and equal to or greater than 60% for laser line wavelengths between 110 and 500 micrometers. This output coupler provides increased output power and flexibility. Beam profile measurements show that the Michelson output coupler produces a well collimated Gaussian laser beam. Design features are: the use of a 10 micrometers reflection coated quartz vacuum window which acts as a dichroic mirror for the pump radiation; the high mechanical stability obtained by leaf sping flexure mount of the movable Michelson mirror and by restricted alignment devices.

  12. Dichroic filters to protect milliwatt far-infrared detectors from megawatt ECRH radiation

    SciTech Connect

    Bertschinger, G.; Oosterbeek, J. W.; Endres, C. P.; Lewen, F.

    2008-10-15

    Dichroic filters have been used to shield effectively the far infrared (FIR) detectors at the interferometer/polarimeter on TEXTOR. The filters consist of metal foils with regular holes, the hole diameter, the mutual spacing and the thickness of the foils are chosen to transmit radiation at the design frequency with transmission >90%. The attenuation at the low frequency end of the bandpass filter is about 30 dB per octave, the high frequency transmission is between 20% and 40%. The filters have been used to block the stray radiation from the megawatt microwave heating beam to the detectors of the FIR interferometer, operating with power on the detector in the milliwatt range. If required, the low frequency attenuation can be still enhanced, without compromising the transmission in the passband. The FIR interferometer used for plasma density and position control is no longer disturbed by electromagnetic waves used for plasma heating.

  13. Time evolution of interstellar dust and far-infrared luminosity of disk galaxies

    NASA Technical Reports Server (NTRS)

    Wang, Boqi

    1991-01-01

    The evolution of interstellar dust in disk galaxies is modeled, assuming that dust forms predominantly in molecular clouds associated with star formation. Analytical solutions for the dust abundance in disk galaxies as a function of galaxy age are obtained for the prompt initial enrichment and accretion models of chemical evolution, consistent with observations of the heavy element abundance in the Galaxy. Star formation rates in the disks of galaxies are taken as either constant or decreasing exponentially with time. It is found that the total amount of dust in the early history of galaxies can be up to 4 times the value observed today. The total emission from dust in galaxies is calculated, using an average dust temperature derived from IRAS observations. In the strongly evolving models, the far-infrared luminosity from galaxies can be roughly two orders of magnitude larger than the current value.

  14. Isotope effects in far-infrared spectra of bis(theophyllinato)copper(II)-complexes

    NASA Astrophysics Data System (ADS)

    Drożdżewski, Piotr; Kordon, Ewa

    1998-07-01

    Far-infrared spectra have been measured for 63Cu and 65Cu isotope substituted theophylline (Tp)-metal ion complexes: Cu(Tp) 2(NH 3) 2 · 2H 2O, Cu(Tp) 2(NH 3) 2, Cu(Tp) 2 · 2H 2O and Cu(Tp) 2. In addition, spectrum of Cu(Tp) 2(ND 3) 2 · 2D 2O has been recorded. Metal-theophylline, metal-ammine and water librational and translational modes have been assigned based on observed isotope shifts and complex dehydration effects. The copper-ammine vibrations have been found at 453 and 224 cm -1, whereas the bis(theophyllinato)copper(II) modes have been detected at 192 cm -1 for Cu(Tp) 2(NH 3) 2 and presumably at about 170 cm -1 for Cu(Tp) 2.

  15. Mid-Infrared Versus Far-Infrared (THz) Relative Intensities of Room-temperature Bacillus Spores

    SciTech Connect

    Johnson, Timothy J.; Valentine, Nancy B.; Sharpe, Steven W.

    2005-02-14

    We have simultaneously recorded the mid-IR and far-IR (sometimes called terahertz, THz) spectra of the sporulated form of five common Bacillus bacteria: Bacillus subtilis ATCC 49760, Bacillus subtilis ATCC 6051, B. thuringiensis subsp. kurstaki ATCC 35866, Bacillus globigii 01, and B. atrophaeus 49337. The 295 K spectra were recorded from {approx}8 to 6,000 cm{sup -1} of samples deposited onto windows transparent in both the mid- and far-infrared. The results indicate that any room-temperature THz absorption features due to the bacterial spores are at least 28 times weaker (based on p-p noise) than the corresponding mid-IR amide I band.

  16. Far Infrared Spectroscopy of H II Regions. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Ward, D. B.

    1975-01-01

    The far infrared spectra of H II regions are investigated. A liquid helium cooled grating spectrometer designed to make observations from the NASA Lear Jet is described along with tests of the instrument. The observing procedure on the Lear Jet telescope is described and the method of data analysis is discussed. Results are presented from a search for the (O III) 88.16 micron line. An upper limit on the emission in this line is obtained and line detection is described. Results are compared to theoretical predictions, and future applications of fine structure line observations are discussed. Coarse resolution results are given along with calibration problems. The spectra obtained are compared to models for dust emission.

  17. Analysis and design of optically pumped far infrared oscillators and amplifiers

    NASA Technical Reports Server (NTRS)

    Galantowicz, T. A.

    1978-01-01

    A waveguide laser oscillator was designed and experimental measurements made of relationships among output power, pressure, pump power, pump frequency, cavity tuning, output beam pattern, and cavity mirror properties for various active gases. A waveguide regenerative amplifier was designed and gain measurements were made for various active gases. An external Fabry-Perot interferometer was fabricated and used for accurate wavelength determination and for measurements of the refractive indices of solids transparent in the far infrared. An electronic system was designed and constructed to provide an appropriate error signal for use in feedback control of pump frequency. Pump feedback from the FIR laser was decoupled using a vibrating mirror to phase modulate the pump signal.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Stable 1.25 watts CW far infrared laser radiation at the 119 micron methanol line

    NASA Technical Reports Server (NTRS)

    Farhoomand, Jam; Pickett, Herbert M.

    1987-01-01

    Far-infrared CW radiation of 1.25 watts has been obtained at the 119 micron methanol line with a CO2 pump power of 125 watts, and the maximum frequency fluctuation of the free running laser is measured to be less than + or - 100 kHz per hour. Reflecting optics have been used, when possible, to minimize CO2 degradation, and the frequency stability is ensured by cooling the input and output couplers. The input and output assemblies within the lasing medium are enclosed to minimize the external effects on the cavity length and to eliminate the mechanical instabilities associated with the use of bellows. The vibrational bottle-neck is broken by cooling the resonator wall to 5 deg and adding He as the buffer gas.

  20. A new, compact far-infrared source in the W31 region

    NASA Technical Reports Server (NTRS)

    Fazio, G. G.; Lada, C. J.; Kleinmann, D. E.; Wright, E. L.; Ho, P. T. P.; Low, F. J.

    1978-01-01

    In a survey of the W31 region, a compact far-infrared source was detected at the position of the radio continuum source G 10.6-0.4. Associated with this infrared source and in close coincidence with its position is an H II region with a compact core and extended halo as well as OH and H2O masers. An extended molecular cloud, centered on these sources, has also been detected. The compact source and associated masers may be located at the H II region-molecular-cloud interface in a thin shocked layer of neutral gas driven into the molecular cloud by the expansion of the H II region. The compact H II region is depleted of dust and must be surrounded by a very dense shell of dust and gas (hydrogen number density in excess of 200,000 per cu cm). The source probably represents an early stage of stellar evolution.