Science.gov

Sample records for infrared finite observables

  1. Catalog of infrared observations

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    The infrared astronomical data base and its principal data product, the catalog of Infrared Observations (CIO), comprise a machine readable library of infrared (1 microns to 1000 microns astronomical observations. To date, over 1300 journal articles and 10 major survey catalogs are included in this data base, which contains about 55,000 individual observations of about 10,000 different infrared sources. Of these, some 8,000 sources are identifiable with visible objects, and about 2,000 do not have known visible counterparts.

  2. 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.

  3. Far infrared supplement: Catalog of infrared observations

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    The development of a new generation of orbital, airborne and ground-based infrared astronomical observatory facilities, including the infrared astronomical satellite (IRAS), the cosmic background explorer (COBE), the NASA Kuiper airborne observatory, and the NASA infrared telescope facility, intensified the need for a comprehensive, machine-readable data base and catalog of current infrared astronomical observations. The Infrared Astronomical Data Base and its principal data product, this catalog, comprise a machine-readable library of infrared (1 micrometer to 1000 micrometers) astronomical observations published in the scientific literature since 1965.

  4. Far infrared supplement: Catalog of infrared observations

    NASA Astrophysics Data System (ADS)

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

    1982-10-01

    The development of a new generation of orbital, airborne and ground-based infrared astronomical observatory facilities, including the infrared astronomical satellite (IRAS), the cosmic background explorer (COBE), the NASA Kuiper airborne observatory, and the NASA infrared telescope facility, intensified the need for a comprehensive, machine-readable data base and catalog of current infrared astronomical observations. The Infrared Astronomical Data Base and its principal data product, this catalog, comprise a machine-readable library of infrared (1 micrometer to 1000 micrometers) astronomical observations published in the scientific literature since 1965.

  5. Infrared observations of comets

    NASA Technical Reports Server (NTRS)

    Hanner, Martha S.

    1991-01-01

    Selected comets are observed in the near infrared (1 to 2.2 micron) and thermal infrared (3.5 to 20 micron) with the NASA Infrared Telescope Facility (IRTF) and other telescopes as appropriate, in order to characterize the physical properties of the dust grains; their composition, size distribution, emissivity, and albedo. Systematic variations in these properties among comets are looked for, in order to understand the heterogeneity of comet nuclei. Spectrophotometry of the 10 micron silicate emission feature is particularly emphasized. The rate of dust production from the nucleus and its temporal variability are also determined. Knowledge of the dust environment is essential to S/C design and mission planning for NASA's CRAF mission.

  6. Mauna Kea Observatory infrared observations

    NASA Technical Reports Server (NTRS)

    Jefferies, J. T.

    1974-01-01

    Galactic and solar system infrared observations are reported using a broad variety of radiometric and spectroscopic instrumentation. Infrared programs and papers published during this period are listed.

  7. 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.

  8. Algorithmic vs. finite difference Jacobians for infrared atmospheric radiative transfer

    NASA Astrophysics Data System (ADS)

    Schreier, Franz; Gimeno García, Sebastián; Vasquez, Mayte; Xu, Jian

    2015-10-01

    Jacobians, i.e. partial derivatives of the radiance and transmission spectrum with respect to the atmospheric state parameters to be retrieved from remote sensing observations, are important for the iterative solution of the nonlinear inverse problem. Finite difference Jacobians are easy to implement, but computationally expensive and possibly of dubious quality; on the other hand, analytical Jacobians are accurate and efficient, but the implementation can be quite demanding. GARLIC, our "Generic Atmospheric Radiation Line-by-line Infrared Code", utilizes algorithmic differentiation (AD) techniques to implement derivatives w.r.t. atmospheric temperature and molecular concentrations. In this paper, we describe our approach for differentiation of the high resolution infrared and microwave spectra and provide an in-depth assessment of finite difference approximations using "exact" AD Jacobians as a reference. The results indicate that the "standard" two-point finite differences with 1 K and 1% perturbation for temperature and volume mixing ratio, respectively, can exhibit substantial errors, and central differences are significantly better. However, these deviations do not transfer into the truncated singular value decomposition solution of a least squares problem. Nevertheless, AD Jacobians are clearly recommended because of the superior speed and accuracy.

  9. Constructing infrared finite propagators in inflating space-time

    SciTech Connect

    Rajaraman, Arvind; Kumar, Jason; Leblond, Louis

    2010-07-15

    The usual (Bunch-Davies) Feynman propagator of a massless field is not well defined in an expanding universe due to the presence of infrared divergences. We propose a new propagator which yields IR finite answers to any correlation function. The key point is that in a de Sitter space-time there is an ambiguity in the zero mode of the propagator. This ambiguity can be used to cancel the apparent divergences which arise in some loop calculations in eternally (or semieternally) inflating space-time. We refer to this process as zero-mode modification. The residual ambiguity is fixed by observational measurement.

  10. Infrared techniques for comet observations

    NASA Technical Reports Server (NTRS)

    Hanner, Martha S.; Tokunaga, Alan T.

    1991-01-01

    The infrared spectral region (1-1000 microns) is important for studies of both molecules and solid grains in comets. Infrared astronomy is in the midst of a technological revolution, with the development of sensitive 2D arrays leading to IR cameras and spectrometers with vastly improved sensitivity and resolution. The Halley campaign gave us tantalizing first glimpses of the comet science possible with this new technology, evidenced, for example, by the many new spectral features detected in the infrared. The techniques of photometry, imaging, and spectroscopy are reviewed in this chapter and their status at the time of the Halley observations is described.

  11. Infrared observations of faint comets

    NASA Technical Reports Server (NTRS)

    Campins, H.; Gradie, J.; Lebofsky, M.; Rieke, G.

    1981-01-01

    Infrared observations of the periodic comets Encke, Stephan-Oterma and Chernykh indicate that the dusty component in this class of comets is not radically different from the dusty component found in nonperiodic comets. The differences in the infrared behavior among these three comets suggest that a range of behaviors rather than a single behavior typifies the cometary activity. The range in albedo (0.02 to 0.10) of the dust calculated for the periodic comets is similar to the range in albedos seen among the asteroids.

  12. Infrared finite ghost propagator in the Feynman gauge

    SciTech Connect

    Aguilar, A. C.; Papavassiliou, J.

    2008-06-15

    We demonstrate how to obtain from the Schwinger-Dyson equations of QCD an infrared finite ghost propagator in the Feynman gauge. The key ingredient in this construction is the longitudinal form factor of the nonperturbative gluon-ghost vertex, which, contrary to what happens in the Landau gauge, contributes nontrivially to the gap equation of the ghost. The detailed study of the corresponding vertex equation reveals that in the presence of a dynamical infrared cutoff this form factor remains finite in the limit of vanishing ghost momentum. This, in turn, allows the ghost self-energy to reach a finite value in the infrared, without having to assume any additional properties for the gluon-ghost vertex, such as the presence of massless poles. The implications of this result and possible future directions are briefly outlined.

  13. Infrared observations of AE Aquarii

    NASA Technical Reports Server (NTRS)

    Tanzi, E. G.; Chincarini, G.; Tarenghi, M.

    1981-01-01

    Broadband infrared observations of the cataclysmic variable AE Aquarii are reported. The observations were obtained in the J, H, K and L filters with the InSb photometer attached to the 1-m telescope of the European Southern Observatory. The infrared energy distribution observed from 0.35 to 3.5 microns for phase 0.5 suggests a spectral type of K5 V for the secondary and a distance to the system of approximately 70 pc if an absolute magnitude of 7.3 is assumed. Monitoring of the flux at 2.2 microns reveals a variability with an amplitude of approximately 0.3 magnitude over one third of the orbital period, the nature of which is under investigation.

  14. Catalog of infrared observations including: Bibliography of infrared astronomy and index of infrared source positions

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    The Catalog of Infrared Observations and its Far Infrared Supplement summarize all infrared astronomical observations at infrared wavelengths published in the scientific literature between 1965 and 1982. The Catalog includes as appendices the Bibliography of infrared astronomy which keys observations in the Catalog with the original journal references, and the index of infrared source positions which gives source positions for alphabetically listed sources in the Catalog. The Catalog data base contains over 85,000 observations of about 10,000 infrared sources, of which about 2,000 have no known visible counterpart.

  15. Catalog of infrared observations. Part 2: Appendixes

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    The Catalog of Infrared Observations (CIO) is a compilation of infrared astronomical observational data obtained from an extensive literature search of astronomical journals and major astronomical catalogs and surveys. The literature searches are complete for years 1965 to 1986. Supporting appendixes are published in this part. The appendices include an atlas of infrared source positions, two bibliographies of infrared literature upon which the search was based, and, keyed to the main Catalog listings (organized alphabetically by first author, and by date), an atlas of infrared spectral ranges, and IRAS data for the CIO sources. The complete CIO database is available to qualified users in printed microfiche and magnetic tape formats.

  16. Observational constraints on finite scale factor singularities

    SciTech Connect

    Denkiewicz, Tomasz

    2012-07-01

    We discuss the combined constraints on a Finite Scale Factor Singularity (FSF) universe evolution scenario, which come from the shift parameter R, baryon acoustic oscillations (BAO) A, and from the type Ia supernovae. We show that observations allow existence of such singularities in the 2 × 10{sup 9} years in future (at 1σ CL) which is much farther than a Sudden Future Singularity (SFS), and that at the present moment of the cosmic evolution, one cannot differentiate between cosmological scenario which allow finite scale factor singularities and the standard ΛCDM dark energy models. We also show that there is an allowed value of m = 2/3 within 1σ CL, which corresponds to a dust-filled Einstein-de-Sitter universe limit of the early time evolution and so it is pasted into a standard early-time scenario.

  17. Catalog of Infrared Observations, Third Edition

    NASA Technical Reports Server (NTRS)

    Gezari, Daniel Y.; Schmitz, Marion; Pitts, Patricia S.; Mead, Jaylee M.

    1993-01-01

    The Far Infrared Supplement contains a subset of the data in the full Catalog of Infrared Observations (all observations at wavelengths greater than 4.6 microns). The Catalog of Infrared Observations (CIO), NASA RP-1294, is a compilation of infrared astronomical observational data obtained from an extensive literature search of scientific journals and major astronomical catalogs and surveys. The literature search is complete for years 1965 through 1990 in this Third Edition. The Catalog contains about 210,000 observations of roughly 20,000 individual sources and supporting appendices. The expanded Third Edition contains coded IRAS 4-band data for all CIO sources detected by IRAS. The appendices include an atlas of infrared source positions (also included in this volume), two bibliographies of Catalog listings, and an atlas of infrared spectral ranges. The complete CIO database is available to qualified users in printed, microfiche, and magnetic-tape formats.

  18. Catalog of infrared observations, third edition

    NASA Astrophysics Data System (ADS)

    Gezari, Daniel Y.; Schmitz, Marion; Pitts, Patricia S.; Mead, Jaylee M.

    1993-06-01

    The Far Infrared Supplement contains a subset of the data in the full Catalog of Infrared Observations (all observations at wavelengths greater than 4.6 microns). The Catalog of Infrared Observations (CIO), NASA RP-1294, is a compilation of infrared astronomical observational data obtained from an extensive literature search of scientific journals and major astronomical catalogs and surveys. The literature search is complete for years 1965 through 1990 in this Third Edition. The Catalog contains about 210,000 observations of roughly 20,000 individual sources and supporting appendices. The expanded Third Edition contains coded IRAS 4-band data for all CIO sources detected by IRAS. The appendices include an atlas of infrared source positions (also included in this volume), two bibliographies of Catalog listings, and an atlas of infrared spectral ranges. The complete CIO database is available to qualified users in printed, microfiche, and magnetic-tape formats.

  19. Finite Element Modeling for Infrared Thermography of Gfrp Bridge Decks

    NASA Astrophysics Data System (ADS)

    Hing, Cheng L.; Halabe, Udaya B.

    2008-02-01

    Glass Fiber Reinforced Polymer (GFRP) composite bridge decks are increasingly being used as replacements for old concrete decks and for new construction. The service performance of the GFRP bridge decks can be adversely affected by the formation of debonds between the wearing surface and the underlying bridge deck. Past experimental studies by the authors have shown the usefulness of the infrared thermography technique in detecting the subsurface debonds prior to maintenance and rehabilitation work. This paper investigates the use of finite element (FE) heat transfer modeling to predict infrared thermography images from GFRP bridge decks with subsurface debonds. The paper includes measurement of thermal properties of the GFRP bridge deck and the wearing surface, and heat transfer FE modeling of decks with debonds of different thicknesses. The results show that FE modeling can be a useful tool for predicting surface temperature profile under different heating conditions and debond sizes. Such predictions can help determine the required heat intensity and detectable debond sizes prior to experimental data acquisition in the field using an infrared camera.

  20. Infrared detectors for Earth observation

    NASA Astrophysics Data System (ADS)

    Barnes, K.; Davis, R. P.; Knowles, P.; Shorrocks, N.

    2016-05-01

    IASI (Infrared Atmospheric Sounding Interferometer), developed by CNES and launched since 2006 on the Metop satellites, is established as a major source of data for atmospheric science and weather prediction. The next generation - IASI NG - is a French national contribution to the Eumetsat Polar System Second Generation on board of the Metop second generation satellites and is under development by Airbus Defence and Space for CNES. The mission aim is to achieve twice the performance of the original IASI instrument in terms of sensitivity and spectral resolution. In turn, this places very demanding requirements on the infrared detectors for the new instrument. Selex ES in Southampton has been selected for the development of the infrared detector set for the IASI-NG instruments. The wide spectral range, 3.6 to 15.5 microns, is covered in four bands, each served by a dedicated detector design, with a common 4 x 4 array format of 1.3 mm square macropixels. Three of the bands up to 8.7 microns employ photovoltaic MCT (mercury cadmium telluride) technology and the very long wave band employs photoconductive MCT, in common with the approach taken between Airbus and Selex ES for the SEVIRI instrument on Second Generation Meteosat. For the photovoltaic detectors, the MCT crystal growth of heterojunction photodiodes is by the MOVPE technique (metal organic vapour phase epitaxy). Novel approaches have been taken to hardening the photovoltaic macropixels against localised crystal defects, and integrating transimpedance amplifiers for each macropixel into a full-custom silicon read out chip, which incorporates radiation hard design.

  1. Infrared Astronomy. [observations of extragalactic sources

    NASA Technical Reports Server (NTRS)

    Neugebauer, G.; Soifer, B. T.; Matthews, K.

    1981-01-01

    Several observational programs in infrared astronomy are described and significant findings are briefly discussed. The near infrared work concentrates largely on the use of the 5 m Hale telescope in spectroscopic and photometric studies of extragalactic sources. Observations of the P alpha line profile in a low redshift quasar, X-ray bursters, reflection nebula, and cataclysmic variables are included. Millimeter continuum observations of dust emission from quasars and galactic molecular clouds are also discussed. Finally, improvements to instrumentation are reported.

  2. Dynamical chiral symmetry with an infrared finite gluon propagator

    NASA Astrophysics Data System (ADS)

    Cardona, J. C.; Aguilar, A. C.

    2016-04-01

    In this work we study dynamical quark mass generation using an infrared finite gluon propagator obtained from quenched lattice simulations. The quark gap equation is solved using a purely non-Abelian Ansatz for the quark-gluon vertex, which displays a dependence on the ghost dressing function and the scalar component of quark-ghost scattering kernel. For the former quantity we use quenched lattice results, while for the latter we derive its own integral equation at the one-loop-dressed approximation. This latter quantity is then coupled to the system of equations governing the two Dirac structures of the quark propagator. It turns out that when a current quark mass of 5 MeV is introduced, the constituent quark mass generated from the gap equation is of the order of 310 MeV. In addition, the pion decay constant computed from the resulting quark propagator is in good agreement with the physical value.

  3. Infrared Observations of Cometary Dust and Nuclei

    NASA Technical Reports Server (NTRS)

    Lisse, Carey

    2004-01-01

    This bibliography lists citations for publications published under the grant. Subjects of the publications include cometary dust, instellar and interplanetary dust, comet nuclei and comae, Comet Hale-Bopp, infrared observations of comets, mass loss, and comet break-up.

  4. Infrared Observations of Cometary Dust and Nuclei

    NASA Technical Reports Server (NTRS)

    Lisse, Carey

    2004-01-01

    This bibliography lists citations for publications published under the grant. Subjects of the publications include cometary dust, instellar and interplanetary dust, comet nuclei and comae, Comet Hale-Bopp, infrared observations of comets, mass loss, and comet break-up.

  5. Infrared array detectors. [for astronomical observation

    NASA Technical Reports Server (NTRS)

    Arens, J. F.

    1982-01-01

    Arrays of detectors sensitive to infrared radiation will enable astronomical observations to be made with shorter observing times than with discrete detectors and with good relative spatial accuracy. Systems using such arrays are being developed for astronomy in several regions of the electromagnetic spectrum. An example of an infrared system is given here consisting of a 32x32 element bismuth doped silicon charge injection device array that has been used in an astronomical camera.

  6. Infrared array detectors. [for astronomical observation

    NASA Technical Reports Server (NTRS)

    Arens, J. F.

    1982-01-01

    Arrays of detectors sensitive to infrared radiation will enable astronomical observations to be made with shorter observing times than with discrete detectors and with good relative spatial accuracy. Systems using such arrays are being developed for astronomy in several regions of the electromagnetic spectrum. An example of an infrared system is given here consisting of a 32x32 element bismuth doped silicon charge injection device array that has been used in an astronomical camera.

  7. Catalog of infrared observations. Part 1: Data

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    The Catalog of Infrared Observations (CIO) is a compilation of infrared astronomical observational data obtained from an extensive literature search of astronomical journals and major astronomical catalogs and surveys. The literature searches are complete for 1965 through 1986 in this Second Edition. The Catalog is published in two parts, with the observational data (roughly 200,000 observations of 20,000 individual sources) listed in Part I, and supporting appendices in Part II. The expanded Second Edition contains a new feature: complete IRAS 4-band data for all CIO sources detected, listed with the main Catalog observations, as well as in complete detail in the Appendix. The appendices include an atlas of infrared source positions, two bibliographies of infrared literature upon which the search was based, and, keyed to the main Catalog listings (organized alphabetically by author and then chronologically), an atlas of infrared spectral ranges, and IRAS data from the CIO sources. The complete CIO database is available to qualified users in printed microfiche and magnetic tape formats.

  8. Astronomical observations with an infrared array camera

    SciTech Connect

    Tresch-Fienberg, R.M.

    1985-01-01

    Astronomical observations with an infrared array camera demonstrate that arrays are excellent for high spatial resolution photometric mapping of celestial objects. The author describes a a 16 x 16 pixel array camera system based on a bismuth-doped silicon charge injection device optimized for use in the 8-13 micron atmospheric window. Observing techniques and image processing algorithms that are unique to the use of an array detector are also discussed. Multi-wavelength, 1-2 arcsec resolution images of three different celestial objects are presented. For the galactic center, maps of the infrared color temperature and emission optical depth are derived. The results are consistent with a model in which a low density region with a massive luminosity source at its center is encircled by a ring of gas and dust from which material may be infalling toward the nucleus. Multiple luminosity sources are not required to explain the infrared appearance of the galactic center. Images of Seyfert galaxy NGC 1068 are the first to resolve the infrared structure of the nucleus and show that it is similar to that at optical and radio wavelengths. Infrared emission extended northeast of the nucleus is identified with the radio jet. Combined with optical spectra and charge coupled device images, the new data imply a causal relationship between the Seyfert activity in the nucleus and the starburst in the disk.

  9. Infrared Observations of Late Type Stars

    NASA Technical Reports Server (NTRS)

    Merrill, K. M.

    1977-01-01

    Substantive mass loss resulting in appreciable circumstellar dust envelopes is common in late-type stars. The evolutionary history and physical state of a cool star determine the chemistry within the outer stellar atmosphere mirrored by the molecular and particulate material present in the envelope. The observational consequences of this debris determined by moderate spectral resolution infrared spectrophotometry are reviewed. Significant information is provided by observations of the emergent energy flux of both the cool stellar photosphere and of the circumstellar dust envelope. The observation suggests that mass-loss occurs to some degree throughout late stellar evolutionary phases and that occasional periods of high mass loss are not uncommon.

  10. Near Infrared Astronomical Observing During the Daytime

    NASA Astrophysics Data System (ADS)

    Tinn Chee Jim, Kevin; Pier, Edward Alan; Cognion, Rita L.

    2015-08-01

    Ground-based, near-infrared astronomy has been mostly restriced to nighttime observing with occasional, bright solar system objects observed during the daytime. But for astronomical phenomena that are time-varying on timescales of less than a day, it would be advantageous to be able to gather data during the day and night. We explore some of the limitations of observing in the J, H, and K bands during the daytime. Atmospheric radiative transfer simulations show that K is the optimal common astronomical filter for daytime observations on Mauna Kea, but the J and H filters can also be used. Observations from Mauna Kea show that it is possible to observe objects at least as faint as K=15.5 during the early afternoon, with photometric accuracies only slightly worse than those obtained at night.

  11. 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.

  12. Dynamical observer for a flexible beam via finite element approximations

    NASA Technical Reports Server (NTRS)

    Manitius, Andre; Xia, Hong-Xing

    1994-01-01

    The purpose of this view-graph presentation is a computational investigation of the closed-loop output feedback control of a Euler-Bernoulli beam based on finite element approximation. The observer is part of the classical observer plus state feedback control, but it is finite-dimensional. In the theoretical work on the subject it is assumed (and sometimes proved) that increasing the number of finite elements will improve accuracy of the control. In applications, this may be difficult to achieve because of numerical problems. The main difficulty in computing the observer and simulating its work is the presence of high frequency eigenvalues in the finite-element model and poor numerical conditioning of some of the system matrices (e.g. poor observability properties) when the dimension of the approximating system increases. This work dealt with some of these difficulties.

  13. Infrared features of unquenched finite temperature lattice Landau gauge QCD

    SciTech Connect

    Furui, Sadataka; Nakajima, Hideo

    2007-09-01

    The color diagonal and color antisymmetric ghost propagators slightly above T{sub c} of N{sub f}=2 MILC 24{sup 3}x12 lattices are measured and compared with zero-temperature unquenched N{sub f}=2+1 MILC{sub c} 20{sup 3}x64 and MILC{sub f} 28{sup 3}x96 lattices and zero-temperature quenched 56{sup 4} {beta}=6.4 and 6.45 lattices. The expectation value of the color antisymmetric ghost propagator {phi}{sup c}(q) is zero, but its Binder cumulant, which is consistent with that of N{sub c}{sup 2}-1 dimensional Gaussian distribution below T{sub c}, decreases above T{sub c}. Although the color diagonal ghost propagator is temperature independent, the l{sup 1} norm of the color antisymmetric ghost propagator is temperature dependent. The expectation value of the ghost condensate observed at zero-temperature unquenched configuration is consistent with 0 in T>T{sub c}. We also measure transverse, magnetic, and electric gluon propagator and extract gluon screening masses. The running coupling measured from the product of the gluon dressing function and the ghost dressing function are almost temperature independent, but the effect of A{sup 2} condensate observed at zero temperature is consistent with 0 in T>T{sub c}. The transverse gluon dressing function at low temperature has a peak in the infrared at low temperature, but it becomes flatter at high temperature. The magnetic gluon propagator at high momentum depends on the temperature. These data imply that the magnetic gluon propagator and the color antisymmetric ghost propagator are affected by the presence of dynamical quarks, and there are strong nonperturbative effects through the temperature-dependent color antisymmetric ghost propagator.

  14. Dynamical renormalization group resummation of finite temperature infrared divergences

    SciTech Connect

    Boyanovsky, D.; de Vega, H.J. ); Boyanovsky, D.; de Vega, H.J.; Simionato, M. et Denis Diderot , Tour 16, 1er. etage, 4, Place Jussieu, 75252 Paris, Cedex 05 ); Holman, R. ); Simionato, M. )

    1999-09-01

    We introduce the method of dynamical renormalization group to study relaxation and damping out of equilibrium directly in real time and apply it to the study of infrared divergences in scalar QED. This method allows a consistent resummation of infrared effects associated with the exchange of quasistatic transverse photons and leads to anomalous logarithmic relaxation of the form e[sup [minus][alpha] hthinsp;T hthinsp;t hthinsp;ln[t/t[sub 0

  15. Infrared algorithm development for ocean observations

    NASA Technical Reports Server (NTRS)

    Brown, Otis B.

    1995-01-01

    Efforts continue under this contract to develop algorithms for the computation of sea surface temperature (SST) from MODIS infrared retrievals. This effort includes radiative transfer modeling, comparison of in situ and satellite observations, development and evaluation of processing and networking methodologies for algorithm computation and data accession, evaluation of surface validation approaches for IR radiances, and participation in MODIS (project) related activities. Efforts in this contract period have focused on radiative transfer modeling, evaluation of atmospheric correction methodologies, involvement in field studies, production and evaluation of new computer networking strategies, and objective analysis approaches.

  16. Infrared spectroscopy of exoplanets: observational constraints

    PubMed Central

    Encrenaz, Thérèse

    2014-01-01

    The exploration of transiting extrasolar planets is an exploding research area in astronomy. With more than 400 transiting exoplanets identified so far, these discoveries have made possible the development of a new research field, the spectroscopic characterization of exoplanets' atmospheres, using both primary and secondary transits. However, these observations have been so far limited to a small number of targets. In this paper, we first review the advantages and limitations of both primary and secondary transit methods. Then, we analyse what kind of infrared spectra can be expected for different types of planets and discuss how to optimize the spectral range and the resolving power of the observations. Finally, we propose a list of favourable targets for present and future ground-based observations. PMID:24664918

  17. Infrared spectroscopy of exoplanets: observational constraints.

    PubMed

    Encrenaz, Thérèse

    2014-04-28

    The exploration of transiting extrasolar planets is an exploding research area in astronomy. With more than 400 transiting exoplanets identified so far, these discoveries have made possible the development of a new research field, the spectroscopic characterization of exoplanets' atmospheres, using both primary and secondary transits. However, these observations have been so far limited to a small number of targets. In this paper, we first review the advantages and limitations of both primary and secondary transit methods. Then, we analyse what kind of infrared spectra can be expected for different types of planets and discuss how to optimize the spectral range and the resolving power of the observations. Finally, we propose a list of favourable targets for present and future ground-based observations.

  18. Infrared observations of the dust coma

    NASA Technical Reports Server (NTRS)

    Campins, Humberto C.; Tokunaga, Alan T.

    1988-01-01

    The main infrared observational results were briefly reviewed at the start of this session. The new results are summarized. All of these results have yet to be synthesized into a self-consistent picture of the dust grain composition, dust production history, outburst mechanisms, and composition of the nucleus. The workshop discussion was helpful in pointing out problems faced by theorists, such as data quality, the lack of the proper theory for computing the scattering and emission of irregular particles, and in some cases the lack of optical constants of realistic materials. It is expected that the gross spectral and dynamical properties of Halley's Comet can be understood in time, even if the details of the observations and the theoretical calculations continue to vex us in the future.

  19. Airborne Infrared Spectrograph for Eclipse Observations

    NASA Astrophysics Data System (ADS)

    Golub, L.; Cheimets, P.; DeLuca, E. E.; Samra, J.; Judge, P. G.

    2015-12-01

    Direct measurements of the coronal magnetic field have significant potential to enhance our understanding of coronal dynamics, and improve forecasting models. Of particular interest are observations of coronal field lines in the Transition Corona, the transitional region between closed and open flux systems, providing important information on eruptive instabilities and on the origin of the slow solar wind. While current instruments routinely observe the photospheric and chromospheric magnetic fields, the proposed airborne spectrometer will take a step toward the direct observation of coronal fields by measuring plasma emission in the infrared at high spatial and spectral resolution. The targeted lines are five forbidden magnetic dipole transitions between 1.4 and 4 um. The airborne system will consist of a telescope, grating spectrometer and pointing/stabilization system to be flown on the NSF/NCAR High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) during the 21 August 2017 total solar eclipse. We will discuss the scientific objectives of the 2017 flight, describe details of the instrument design, and present the observing program for the eclipse.

  20. Io Eclipse Observations: Does Loki Dominate Io's Infrared Flux?

    NASA Astrophysics Data System (ADS)

    Rathbun, J. A.; Spencer, J. R.

    2008-03-01

    Observations of Io's thermal infrared emission made from NASA's IRTF will be presented. We will determine whether Loki dominates Io's infrared flux and attempt to separate Loki's flux in order to compare it to a quantitative model of its eruption.

  1. Unified description of seagull cancellations and infrared finiteness of gluon propagators

    NASA Astrophysics Data System (ADS)

    Aguilar, A. C.; Binosi, D.; Figueiredo, C. T.; Papavassiliou, J.

    2016-08-01

    We present a generalized theoretical framework for dealing with the important issue of dynamical mass generation in Yang-Mills theories, and, in particular, with the infrared finiteness of the gluon propagators, observed in a multitude of recent lattice simulations. Our analysis is manifestly gauge invariant, in the sense that it preserves the transversality of the gluon self-energy, and gauge independent, given that the conclusions do not depend on the choice of the gauge-fixing parameter within the linear covariant gauges. The central construction relies crucially on the subtle interplay between the Abelian Ward identities satisfied by the nonperturbative vertices and a special integral identity that enforces a vast number of "seagull cancellations" among the one- and two-loop dressed diagrams of the gluon Schwinger-Dyson equation. The key result of these considerations is that the gluon propagator remains rigorously massless, provided that the vertices do not contain (dynamical) massless poles. When such poles are incorporated into the vertices, under the pivotal requirement of respecting the gauge symmetry of the theory, the terms comprising the Ward identities conspire in such a way as to still enforce the total annihilation of all quadratic divergences, inducing, at the same time, residual contributions that account for the saturation of gluon propagators in the deep infrared.

  2. Finite field of view effects on inversion of limb thermal emission observations. [balloon sounding of stratosphere

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Guo, J.; Conrath, B. J.; Kunde, V. G.; Maguire, W. C.

    1985-01-01

    It is pointed out that the technique of thermal emission spectroscopy provides an effective means for remote sounding of stratospheric temperature structure and constituent distributions. One procedure for measuring the stratospheric infrared spectrum involves the conduction of observations along ray paths tangent to the stratospheric limb. Thermal emission limb tangent observations have certain advantages compared to other types of observations. The techniques for determining temperature and trace gas distributions from limb thermal emission radiances are based on the assumption that the bulk of opacity lies near the tangent point. Ideally, the field of view (FOV) of the observing instrument should be very small. The effect of a finite FOV is to reduce the spatial resolution of the retrieved temperature and constituent profiles. The present investigation is concerned with the effects of the FOV on the inversion of infrared thermal emission measurements for balloon platforms. Attention is given to a convenient method for determining the weighting functions.

  3. Finite element corroboration of buckling phenomena observed in corrugated boxes

    Treesearch

    Thomas J. Urbanik; Edmond P. Saliklis

    2003-01-01

    Conventional compression strength formulas for corrugated fiberboard boxes are limited to geometry and material that produce an elastic postbuckling failure. Inelastic postbuckling can occur in squatty boxes and trays, but a mechanistic rationale for unifying observed strength data is lacking. This study combines a finite element model with a parametric design of the...

  4. Infrared observations of small solar system bodies

    NASA Technical Reports Server (NTRS)

    Brown, R. H.

    1991-01-01

    Infrared reflectance spectra were measured of dark primitive asteroids in the 2 to 5 micron wavelength region. The search was for organic complexes such and CN, CH, and NH in dark material on small bodies in the solar system. A search and study was made of volatiles such as nitrogen, methane, ammonia, and carbon monoxide, both as free ices and hydrates/clathrates, on icy surfaces in the outer solar system, using high resolution spectra obtained with a multichannel cooled grating, infrared spectrometer. An absorption that can be attributed to X-C (triple bond) N in the matrix of dark materials on the primitive asteroids.

  5. Easy Observation of Infrared Spectral Lines

    ERIC Educational Resources Information Center

    Cortel, Adolf

    2012-01-01

    The spectra of some chemical elements display intense infrared (IR) lines that can be used more effectively than the ones in the visible region for identification purposes. A simple setup, based on the IR sensitivity of a handycam in nightshot mode, is described to record the visible as well as the IR spectra from decorative bulbs or salts on the…

  6. Easy Observation of Infrared Spectral Lines

    ERIC Educational Resources Information Center

    Cortel, Adolf

    2012-01-01

    The spectra of some chemical elements display intense infrared (IR) lines that can be used more effectively than the ones in the visible region for identification purposes. A simple setup, based on the IR sensitivity of a handycam in nightshot mode, is described to record the visible as well as the IR spectra from decorative bulbs or salts on the…

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

  8. Infrared Observations of the Solar System in Support of Large Aperture Infrared Telescope (LARITS): Calibration

    DTIC Science & Technology

    1990-04-01

    Body Thermal Emission from The Full Moon A-4 5.5 Thesis Proposal:Surface Roughness and Infrared Emission from Solid- Surfaced Planetary Bodies Accession...Non-Gray-Body Thermal Thermal Emission from the Full Moon " and is being 0 reviewed by Icarus. 3 AFOSR85-0181 INFRARED OBSERVATIONS OF THE SOLAR SYSTEM...Icarus, Modeling the Non-Gray-Body Thermal Emission from the Full Moon , ( 5.5 ) Surface Roughness and Infrared Emission from Solid- Surfaced

  9. Cooled grating infrared spectrometer for astronomical observations

    NASA Technical Reports Server (NTRS)

    Houck, J. R.; Gull, G. E.

    1983-01-01

    A liquid helium-cooled infrared spectrometer for the 16 to 50 micron range is described. The instrument has six detectors, three each of Si:Sb and Ge:Ga and two diffraction gratings mounted back-to-back. Cold preoptics are used to match the spectrometer to the telescope. In its nominal configuration the system resolution is 0.03 micron from 16 to 30 microns and 0.07 micron from 28 to 50 microns. A cooled filter wheel is used to change order sorting filters. The gratings are driven by a steel band and gear train operating at 4 K. The detector outputs are amplified by a TIA, employing a matched pair of JFETs operating at 70 K inside the dewar. The external warm electronics include a gain stage for the TIA and dc-coupled gating circuit to remove charged-particle (cosmic-ray secondary)-induced noise spikes. The gating circuit reduces the overall system noise by a factor of two when the spectrometer is used on NASA's Kuiper Airborne Observatory. Sample spectra are presented and the deglitcher performance is illustrated.

  10. Infrared Observations Of Saturn's Rings : Azimuthal Variations And Thermal Modeling

    NASA Astrophysics Data System (ADS)

    Leyrat, C.; Spilker, L. J.; Altobelli, N.; Pilorz, S.; Ferrari, C.; Edgington, S. G.; Wallis, B. D.; Nugent, C.; Flasar, M.

    2007-12-01

    Saturn's rings represent a collection of icy centimeter to meter size particles with their local dynamic dictated by self gravity, mutual collisions, surface roughness and thickness of the rings themselves. The infrared observations obtained by the CIRS infrared spectrometer on board Cassini over the last 3.5 year contain informations on the local dynamic, as the thermal signature of planetary rings is influenced both by the ring structure and the particle properties. The ring temperature is very dependent on the solar phase angle (Spilker et al., this issue), and on the local hour angle around Saturn, depending on whether or not particles' visible hemispheres are heated by the Sun. The geometric filling factor, which can be estimated from CIRS spectra, is less dependent on the local hour angle, suggesting that the non isothermal behavior of particles' surfaces have low impact, but it is very dependent on the spacecraft elevation for the A and C rings. The ring small scale structure can be explored using CIRS data. Variations of the filling factor with the local hour angle relative to the spacecraft azimuth reveals self-gravity wakes. We derive morphological parameters of such wakes in both A and B rings assuming that wakes can be modeled either by regularly spaced bars with infinite or finite optical depth. Our results indicates that wakes in the A ring are almost flat, with a ratio height/width ≈ 0.44 ± 0.16 and with a pitch angle relative to the orbital motion direction of ≍ 27deg. This is consistent with UVIS (Colwell et al., 2006) and VIMS data (Hedman et al., 2007). Such models are more difficult to constrain in the B ring, but small variations of the filling factor indicate that the pitch angle decreases drastically in this ring. We also present a new thermal bar model to explain azimuthal variations of temperatures in the A ring. We compare results with previous ring thermal models of spherical particles. The Cassini/CIRS azimuthal scans data set is

  11. Observed Asteroid Surface Area in the Thermal Infrared

    NASA Astrophysics Data System (ADS)

    Nugent, C. R.; Mainzer, A.; Masiero, J.; Wright, E. L.; Bauer, J.; Grav, T.; Kramer, E.; Sonnett, S.

    2017-02-01

    The rapid accumulation of thermal infrared observations and shape models of asteroids has led to increased interest in thermophysical modeling. Most of these infrared observations are unresolved. We consider what fraction of an asteroid’s surface area contributes the bulk of the emitted thermal flux for two model asteroids of different shapes over a range of thermal parameters. The resulting observed surface in the infrared is generally more fragmented than the area observed in visible wavelengths, indicating high sensitivity to shape. For objects with low values of the thermal parameter, small fractions of the surface contribute the majority of thermally emitted flux. Calculating observed areas could enable the production of spatially resolved thermal inertia maps from non-resolved observations of asteroids.

  12. 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.

  13. Infrared imaging-spectroscopic observations of Venus atmosphere

    NASA Astrophysics Data System (ADS)

    Ohtsuki, Shoko; Sagawa, Hideo; Ueno, Munetaka

    2005-01-01

    We present a report on our recent observations of Venus atmosphere which we have performed in infrared wavelength at Okayama Astrophysical Observatory. The data show important results on the CO distribution and on O2 IRA (0,0) 1.27μm airglow in the atmosphere. The infrared windows of the Venusian atmosphere are rather developing areas and will give us important information on the dynamics of Venus atmosphere.

  14. Near-infrared photometric observations of Nova Ophiuchi 2012

    NASA Astrophysics Data System (ADS)

    Raj, Ashish; Ashok, N. M.; Banerjee, D. P. K.; Raman, V. Venkata

    2012-04-01

    Ashish Raj, N. M. Ashok, D. P. K. Banerjee and V. Venkata Raman, Physical Research Laboratory, report near-infrared J-, H-, and K-band photometry of the Nova Oph 2012 (cf. CBET 3072, 3081) obtained with the Mt. Abu 1.2-m telescope (+PRL Near-Infrared NICMOS3 Imager/Spectrometer). The preliminary reduction of these Mt. Abu observations, of Mar. 29, 31 and Apr. 2, 3 UT shows the brightening of the nova in the JHK bands.

  15. Infrared Observations in Antarctica: the SPIREX Project

    NASA Astrophysics Data System (ADS)

    Rathborne, Jill

    The 60cm SPIREX telescope located at the Amundsen-Scott South Pole Station was the first prototype system for a thermal IR imager in Antarctica. Observations over two winter seasons achieved remarkably high resolution wide field images in the wavelength range 3--5um across many star forming complexes. These images in particular reveal the locations of photodissociation regions (PDRs) and pinpoint young objects through their high L-band fluxes. This talk will give a briefly review of the SPIREX project and present a summary of observational results. The SPIREX project was a collaboration between the Center for Astrophysical Research in Antarctica (CARA) the National Optical Astronomy Observatories (NOAO) and the Joint Australian Centre for Astrophysical Research in Antarctica (JACARA).

  16. Infrared observations of outer planet satellites

    NASA Technical Reports Server (NTRS)

    Johnson, T. V.

    1988-01-01

    This task supports IR observations of the outer planet satellites. These data provide vital information about the thermophysical properties of satellite surfaces, including internal heat sources for Io. Observations include both broad and narrow band measurementsin the 2 to 20 micrometer spectral range. The program in the last year has aimed at obtaining lonitude coverage on Io to establish stability of hot spot patterns previously reported. Several runs produced the most complete data set for an apparition since the start of the program. Unfortunately, bad weather limited coverage of key longitude ranges containing the largest known hot spot Loki. Among the preliminary results is the observation of an outburst in Io's thermal flux that was measured at 4.8, 8.7 and 20 micrometer. Analysis of the data has given the best evidence to date of silicate volcanism on Io; this is one of the most significant pieces of the puzzle as to the relative roles of silicate and sulfur volcanism on Io. Researchers are collaborating with J. Goguen (NRC RRA to finish reduction of mutual event data, which have already improved ephermeris information for the satellites. The data appear to place significant limits on the characteristics of any leading side hot spots.

  17. Infrared observations of the Neptunian system

    NASA Technical Reports Server (NTRS)

    Conrath, B.; Flasar, F. M.; Hanel, R.; Kunde, V.; Maguire, W.; Pearl, J.; Pirraglia, J.; Samuelson, R.; Cruikshank, D.; Horn, L.

    1989-01-01

    Voyager 2's IR observations of Neptune encompass thermal emissions and broadband radiometer measurements of reflected solar radiation. Temperature maps were obtained for the planet between 80 deg S and 30 deg N for two atmospheric layers, one in the lower stratosphere and the other in the troposphere. The relatively warm pole and equator, with cooler midlatitudes, are qualitatively similar to Uranus, despite the two planets' very different obliquities and internal heat fluxes. Powerful wavelike longitudinal thermal structure is noted, of which some appears to be associated with the Great Dark Spot; a localized cold region uncorrelated with any visible feature is found in the lower stratosphere.

  18. A method for combining passive microwave and infrared rainfall observations

    NASA Technical Reports Server (NTRS)

    Kummerow, Christian; Giglio, Louis

    1995-01-01

    Because passive microwave instruments are confined to polar-orbiting satellites, rainfall estimates must interpolate across long time periods, during which no measurements are available. In this paper the authors discuss a technique that allows one to partially overcome the sampling limitations by using frequent infrared observations from geosynchronous platforms. To accomplish this, the technique compares all coincident microwave and infrared observations. From each coincident pair, the infrared temperature threshold is selected that corresponds to an area equal to the raining area observed in the microwave image. The mean conditional rainfall rate as determined from the microwave image is then assigned to pixels in the infrared image that are colder than the selected threshold. The calibration is also applied to a fixed threshold of 235 K for comparison with established infrared techniques. Once a calibration is determined, it is applied to all infrared images. Monthly accumulations for both methods are then obtained by summing rainfall from all available infrared images. Two examples are used to evaluate the performance of the technique. The first consists of a one-month period (February 1988) over Darwin, Australia, where good validation data are available from radar and rain gauges. For this case it was found that the technique approximately doubled the rain inferred by the microwave method alone and produced exceptional agreement with the validation data. The second example involved comparisons with atoll rain gauges in the western Pacific for June 1989. Results here are overshadowed by the fact that the hourly infrared estimates from established techniques, by themselves, produced very good correlations with the rain gauges. The calibration technique was not able to improve upon these results.

  19. Finite Volume Numerical Methods for Aeroheating Rate Calculations from Infrared Thermographic Data

    NASA Technical Reports Server (NTRS)

    Daryabeigi, Kamran; Berry, Scott A.; Horvath, Thomas J.; Nowak, Robert J.

    2003-01-01

    The use of multi-dimensional finite volume numerical techniques with finite thickness models for calculating aeroheating rates from measured global surface temperatures on hypersonic wind tunnel models was investigated. Both direct and inverse finite volume techniques were investigated and compared with the one-dimensional semi -infinite technique. Global transient surface temperatures were measured using an infrared thermographic technique on a 0.333-scale model of the Hyper-X forebody in the Langley Research Center 20-Inch Mach 6 Air tunnel. In these tests the effectiveness of vortices generated via gas injection for initiating hypersonic transition on the Hyper-X forebody were investigated. An array of streamwise orientated heating striations were generated and visualized downstream of the gas injection sites. In regions without significant spatial temperature gradients, one-dimensional techniques provided accurate aeroheating rates. In regions with sharp temperature gradients due to the striation patterns two-dimensional heat transfer techniques were necessary to obtain accurate heating rates. The use of the one-dimensional technique resulted in differences of 20% in the calculated heating rates because it did not account for lateral heat conduction in the model.

  20. Infrared observations of the Uranian system

    NASA Technical Reports Server (NTRS)

    Hanel, R.; Conrath, B.; Flasar, F. M.; Kunde, V.; Maquire, W.; Pearl, J.; Pirraglia, J.; Samuelson, R.; Horn, L.; Schulte, P.

    1986-01-01

    Initial results are presented from analyses of IR interferometer spectrometer data collected by Voyager 2 during passes of Uranus and the moons Miranda and Ariel. The data covered reflected solar radiation in the visible and near-IR and thermal emissions between 25 and 50 microns. An equatorial atmospheric He mole fraction of 0.10-0.20 and a mass fraction of 0.16-0.34 was observed for Uranus. Para-hydrogen was also a significant fraction Uranus CH4 atmosphere. Average polar and equatorial spectra were employed to generate vertical temperature profiles between 60-900 mbar, with the finding that the temperatures at the equator and the poles are markedly similar between 400-900 mbar. The effective temperature of Uranus had a calculated upper limit of about 59.4 K, while the subsolar temperatures of Miranda and Arial were around 86 and 84 K, respectively. The albedos of the two satellites indicated surface microstructures composed of isotopically scattering grains.

  1. Near-infrared observations of the variable crab nebula

    NASA Astrophysics Data System (ADS)

    Yamamoto, M.; Mori, K.; Shibata, S.; Tsujimoto, M.; Misawa, T.; Burrows, D.; Kawai, N.

    We present three near-infrared NIR observations of the Crab Nebula obtained with CISCO on the Subaru Telescope and Quick Infrared Camera on the University of HAWAII 88 inch Telescope The observations were performed on 2004 September 2005 February and 2005 October and were coordinated with X-ray observations obtained with the Chandra X-ray observatory within 10 days As shown in previous optical and X-ray monitoring observations outward-moving wisps and variable knots are detected also in our NIR observations The NIR variations are closely correlated with variations in the X-ray observations indicating that both variations are driven by the same physical process We discuss the origin of NIR-emitting particles based on the temporal variations as well as the spectral energy distributions of each variable component

  2. 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.

  3. An Airborne Infrared Spectrometer for Solar Eclipse Observations

    NASA Astrophysics Data System (ADS)

    Samra, Jenna; DeLuca, Edward E.; Golub, Leon; Cheimets, Peter; Philip, Judge

    2016-05-01

    The airborne infrared spectrometer (AIR-Spec) is an innovative solar spectrometer that will observe the 2017 solar eclipse from the NSF/NCAR High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER). AIR-Spec will image five infrared coronal emission lines to determine whether they may be useful probes of coronal magnetism.The solar magnetic field provides the free energy that controls coronal heating, structure, and dynamics. Energy stored in coronal magnetic fields is released in flares and coronal mass ejections and ultimately drives space weather. Therefore, direct coronal field measurements have significant potential to enhance understanding of coronal dynamics and improve solar forecasting models. Of particular interest are observations of field lines in the transitional region between closed and open flux systems, providing important information on the origin of the slow solar wind.While current instruments routinely observe only the photospheric and chromospheric magnetic fields, AIR-Spec will take a step toward the direct observation of coronal fields by measuring plasma emission in the infrared at high spatial and spectral resolution. During the total solar eclipse of 2017, AIR-Spec will observe five magnetically sensitive coronal emission lines between 1.4 and 4 µm from the HIAPER Gulfstream V at an altitude above 14.9 km. The instrument will measure emission line intensity, width, and Doppler shift, map the spatial distribution of infrared emitting plasma, and search for waves in the emission line velocities.AIR-Spec consists of an optical system (feed telescope, grating spectrometer, and infrared detector) and an image stabilization system, which uses a fast steering mirror to correct the line-of-sight for platform perturbations. To ensure that the instrument meets its research goals, both systems are undergoing extensive performance modeling and testing. These results are shown with reference to the science requirements.

  4. Finite Volume Numerical Methods for Aeroheating Rate Calculations from Infrared Thermographic Data

    NASA Technical Reports Server (NTRS)

    Daryabeigi, Kamran; Berry, Scott A.; Horvath, Thomas J.; Nowak, Robert J.

    2006-01-01

    The use of multi-dimensional finite volume heat conduction techniques for calculating aeroheating rates from measured global surface temperatures on hypersonic wind tunnel models was investigated. Both direct and inverse finite volume techniques were investigated and compared with the standard one-dimensional semi-infinite technique. Global transient surface temperatures were measured using an infrared thermographic technique on a 0.333-scale model of the Hyper-X forebody in the NASA Langley Research Center 20-Inch Mach 6 Air tunnel. In these tests the effectiveness of vortices generated via gas injection for initiating hypersonic transition on the Hyper-X forebody was investigated. An array of streamwise-orientated heating striations was generated and visualized downstream of the gas injection sites. In regions without significant spatial temperature gradients, one-dimensional techniques provided accurate aeroheating rates. In regions with sharp temperature gradients caused by striation patterns multi-dimensional heat transfer techniques were necessary to obtain more accurate heating rates. The use of the one-dimensional technique resulted in differences of 20% in the calculated heating rates compared to 2-D analysis because it did not account for lateral heat conduction in the model.

  5. Infrared sensing of non-observable human biometrics

    NASA Astrophysics Data System (ADS)

    Willmore, Michael R.

    2005-05-01

    Interest and growth of biometric recognition technologies surged after 9/11. Once a technology mainly used for identity verification in law enforcement, biometrics are now being considered as a secure means of providing identity assurance in security related applications. Biometric recognition in law enforcement must, by necessity, use attributes of human uniqueness that are both observable and vulnerable to compromise. Privacy and protection of an individual's identity is not assured during criminal activity. However, a security system must rely on identity assurance for access control to physical or logical spaces while not being vulnerable to compromise and protecting the privacy of an individual. The solution resides in the use of non-observable attributes of human uniqueness to perform the biometric recognition process. This discussion will begin by presenting some key perspectives about biometric recognition and the characteristic differences between observable and non-observable biometric attributes. An introduction to the design, development, and testing of the Thermo-ID system will follow. The Thermo-ID system is an emerging biometric recognition technology that uses non-observable patterns of infrared energy naturally emanating from within the human body. As with all biometric systems, the infrared patterns recorded and compared within the Thermo-ID system are unique and individually distinguishable permitting a link to be confirmed between an individual and a claimed or previously established identity. The non-observable characteristics of infrared patterns of human uniqueness insure both the privacy and protection of an individual using this type of biometric recognition system.

  6. Summary of observations of the infrared camera (IRC) onboard AKARI

    NASA Astrophysics Data System (ADS)

    Onaka, T.; Matsuhara, H.; Wada, T.; Ishihara, D.; Ohyama, Y.; Sakon, I.; Shimonishi, T.; Ohsawa, R.; Mori, T. I.; Egusa, F.; Usui, F.; Takita, S.; Murakami, H.; Oyabu, S.; Yamagishi, M.; Mori, T.; Mouri, A.; Kondo, T.; Suzuki, S.; Kaneda, H.; Ita, Y.; Ootsubo, T.

    2012-09-01

    AKARI, the Japanese satellite mission dedicated to infrared astronomy was launched in 2006 February and exhausted its liquid helium in 2007 August. During the cold mission phase, the Infrared Camera (IRC) onboard carried out an all-sky survey at 9 and 18µm with better spatial resolution and higher sensitivity than IRAS. Both bands also have slightly shorter wavelength coverage than IRAS 12 and 25μm bands and thus provide different information on the infrared sky. All-sky image data of the IRC are now in the final processing and will be released to the public within a year. After the exhaustion of the cryogen, the telescope and focal plane instruments of AKARI had still been kept at sufficiently low temperatures owing to the onboard cryocooler. Near-infrared (NIR) imaging and spectroscopic observations with the IRC had continued until 2011 May, when the spacecraft had a serious problem in the power supply system that forced us to terminate the observation. The IRC carried out nearly 20000 pointing observations in total despite of its near-earth orbit. About a half of them were performed after the exhaustion of the cryogen in the spectroscopic modes, which provided high-sensitivity NIR spectra from 2 to 5µm without disturbance of the terrestrial atmosphere. During the warm mission phase, the temperature of the instrument gradually increased and changed the array operation conditions. We present a summary of AKARI/IRC observations, including the all-sky mid-infrared diffuse data as well as the data taken in the warm mission phase.

  7. Titan's Atmospheric Composition from Observations by the Cassini Infrared Spectrometer

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; LeClair, A.; Flasar, F. M.; Kunde, V. G.; Conrath, B. J.; Coustenis, A.; Jennings, D. J.; Nixon, C. A.; Brasunas, J.; Achterberg, R. K.

    2006-01-01

    The Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft has been making observations during the fly-bys of Titan since the Saturn-Orbit-Insertion in July 2004. The observations provide infrared them1 emission spectra of Titan s atmosphere in three spectral channels covering the 10/cm to 1400/cm spectral region, with variable spectral resolutions of 0.53/cm and 2.8/cm. The uniquely observed spectra exhibit rotational and vibrational-rotational spectral lines of the molecular constituents of Titan s atmosphere that may be analyzed to retrieve information about the composition, thermal structure, and physical and dynamical processes in the remotely sensed atmosphere. We present an analysis of Titan's infrared spectra observed during July 2004 (TO), December 2004 (Tb) and February 2005 (T3), for retrieval of the stratospheric thermal structure, distribution of the hydrocarbons, nitriles, and oxygen bearing constituents, such as C2H2, C2H4, C2H6, C3H8, HCN, HC3N, CO, and CO2 . Preliminary results on the distribution and opacity of haze in Titan s atmosphere are discussed.

  8. Titan's Atmospheric Composition from Observations by the Cassini Infrared Spectrometer

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; LeClair, A.; Flasar, F. M.; Kunde, V. G.; Conrath, B. J.; Coustenis, A.; Jennings, D. J.; Nixon, C. A.; Brasunas, J.; Achterberg, R. K.

    2006-01-01

    The Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft has been making observations during the fly-bys of Titan since the Saturn-Orbit-Insertion in July 2004. The observations provide infrared them1 emission spectra of Titan s atmosphere in three spectral channels covering the 10/cm to 1400/cm spectral region, with variable spectral resolutions of 0.53/cm and 2.8/cm. The uniquely observed spectra exhibit rotational and vibrational-rotational spectral lines of the molecular constituents of Titan s atmosphere that may be analyzed to retrieve information about the composition, thermal structure, and physical and dynamical processes in the remotely sensed atmosphere. We present an analysis of Titan's infrared spectra observed during July 2004 (TO), December 2004 (Tb) and February 2005 (T3), for retrieval of the stratospheric thermal structure, distribution of the hydrocarbons, nitriles, and oxygen bearing constituents, such as C2H2, C2H4, C2H6, C3H8, HCN, HC3N, CO, and CO2 . Preliminary results on the distribution and opacity of haze in Titan s atmosphere are discussed.

  9. The Infrared Database of Extragalactic Observables from Spitzer (IDEOS)

    NASA Astrophysics Data System (ADS)

    Spoon, Henrik

    During the cryogenic phase of the successful Spitzer mission the Infrared Spectrograph (IRS) performed approximately 15,000 observations of galactic and extragalactic sources. Among these are low-resolution spectra of more than 4200 galaxies beyond the Local Group. Results have been published in a great number of papers, led not only by hardcore infrared observers but increasingly also by non-native infrared astronomers. As the PI team of the IRS instrument, we are especially proud of the achievements of the IRS spectrograph, and we feel a special obligation to enhance the legacy value of its many observations. Last Summer we completed the Cornell Atlas of Spitzer-IRS Sources (CASSIS), containing homogeneously, expert-reduced low-resolution IRS spectra for over 11,000 observations. The spectra are available for download from our newly created CASSIS web portal. Here we propose to continue these efforts by fitting the low-resolution extragalactic spectra in the CASSIS atlas and create an Infrared Database of Extragalactic Observables from Spitzer (IDEOS) of homogeneously measured mid-infrared spectroscopic observables of more than 4200 galaxies beyond the Local Group. IDEOS will provide astronomers with widely varying scientific interests access to diagnostics that were previously available only for limited samples, or available on-the- fly only to expert users. The completion of IDEOS will coincide with the completion of ALMA. By their nature, CASSIS galaxies are attractive targets for high S/N ALMA observations. IDEOS will provide easily-accessible mid-IR selection criteria for compilation of ALMA target lists for probing significant questions on the AGN environment, the nature of starburst activity, or the AGN/starburst connection. The virtual observatory accessibility will also greatly automate the collation of synoptic results, particularly in the compilation of SEDs and in the cross-matching of targets for trend plots of spectroscopic observables. IDEOS will

  10. Milli-Arcsecond Infrared Observations of the Nova RS Ophiuchi

    NASA Technical Reports Server (NTRS)

    Barry, Richard K.; Danchi, W. C.; Koresko, C.; Kuchner, M.; Traub, W. A.; Monnier, J. D.; Serabyn, E.; Mennesson, B.; Greenhouse, M. A.; Colavita, M. M.; hide

    2007-01-01

    We report on infrared interferometric measurements of the 2006 outburst of Nova RS Oph in H, K, and N bands. These measurements, conducted using the Infrared and Optical Telescope Array, the Palomar Testbed Interferometer, and the Keck Interferometer, show a small variation in the 3 mas size if this resolved source during the first 65 days of the outburst. Additionally, using interferometric closure phases, these observations show an unambiguous departure from point symmetry of the object. We also describe simultaneous N-band observations of the nova in two separate milli-arcsecond spatial regimes on day four in which we detect line emission indicating onset of the optically thin phase. These data represent the first science from the Keck Interferometer's nulling mode.

  11. Infrared Observations Of Dust Emission From Comet Hale-Bopp

    NASA Astrophysics Data System (ADS)

    Lisse, C. M.; Fernández, Y. R.; A'Hearn, M. F.; Kostiuk, T.; Livengood, T. A.; Käufl, H. U.; Hoffmann, W. F.; Dayal, A.; Ressler, M. E.; Hanner, M. S.; Fazio, G. G.; Hora, J. L.; Peschke, S. B.; Grün, E.; Deutsch, L. K.

    1997-07-01

    We present infrared imaging and photometry of the bright, giant comet C/1995 O1 (Hale-Bopp). The comet was observed in an extended infrared and optical observing campaign in 1996 1997. The infrared morphology of the comet was observed to change from the 6 to 8 jet “porcupine” structure in 1996 to the “pinwheel” structure seen in 1997; this has implications for the position of the rotational angular momentum vector. Long term light curves taken at 11.3 μm indicate a dust production rate that varies with heliocentric distance as ∶ r-1.4. Short term light curves taken at perihelion indicate a rotational periodicity of 11.3 hours and a projected dust outflow speed of ∶ 0.4 km s-1. The spectral energy distribution of the dust on October 31, 1996 is well modeled by a mixture of 70% silicaceous and 30% carbonaceous non-porous grains, with a small particle dominated size distribution like that seen for comet P/Halley (McDonnell et al., 1991), an overall dust production rate of 2 × 105 kg s-1, a dust-to-gas ratio of ∶5, and an albedo of 39%.

  12. Finite-Time Control by Observer-Based Output Feedback for Linear Discrete-Time Systems

    NASA Astrophysics Data System (ADS)

    Ichihara, Hiroyuki; Katayama, Hitoshi

    In this paper we consider finite-time stabilization and finite-time boundedness control problems for time-varying discrete-time systems. We give a set of sufficient conditions, in terms of difference LMIs, for the existence of observer-based output feedback controllers that make the system finite-time stable and finite-time bounded. We then reduce the obtained results to the ones for time-invariant discrete-time systems and derive numerically tractable sufficient conditions given by LMIs. We also show numerical examples to illustrate the design methods of observer-based output feedback controllers.

  13. VLBI observations of Infrared-Faint Radio Sources

    NASA Astrophysics Data System (ADS)

    Middelberg, Enno; Phillips, Chris; Norris, Ray; Tingay, Steven

    2006-10-01

    We propose to observe a small sample of radio sources from the ATLAS project (ATLAS = Australia Telescope Large Area Survey) with the LBA, to determine their compactness and map their structures. The sample consists of three radio sources with no counterpart in the co-located SWIRE survey (3.6 um to 160 um), carried out with the Spitzer Space Telescope. This rare class of sources, dubbed Infrared-Faint Radio Sources, or IFRS, is inconsistent with current galaxy evolution models. VLBI observations are an essential way to obtain further clues on what these objects are and why they are hidden from infrared observations: we will map their structure to test whether they resemble core-jet or double-lobed morphologies, and we will measure the flux densities on long baselines, to determine their compactness. Previous snapshot-style LBA observations of two other IFRS yielded no detections, hence we propose to use disk-based recording with 512 Mbps where possible, for highest sensitivity. With the observations proposed here, we will increase the number of VLBI-observed IFRS from two to five, soon allowing us to draw general conclusions about this intriguing new class of objects.

  14. Infrared observations of the Saturnian system from Voyager 2

    NASA Technical Reports Server (NTRS)

    Hanel, R.; Conrath, B.; Flasar, F. M.; Kunde, V.; Maguire, W.; Pearl, J.; Pirraglia, J.; Samuelson, R.; Cruikshank, D.; Gautier, D.

    1982-01-01

    During the passage of Voyager 2 through the Saturn system, infrared spectral and radiometric data were obtained for Saturn, Titan, Enceladus, Tethys, Iapetus, and the rings. Combined Voyager 1 and Voyager 2 observations of temperatures in the upper troposphere of Saturn indicate a seasonal asymmetry between the northern and southern hemispheres, with superposed small-scale meridional gradients. Comparison of high spatial resolution data from the two hemispheres poleward of 60 deg latitude suggests an approximate symmetry in the small-scale structure, consistent with the extension of a symmetric system of zonal jets into the polar regions. Longitudinal variations of 1 to 2 K are observed. Disk-averaged infrared spectra of Titan show little change over the 9-month interval between Voyager encounters. By combining Voyager 2 temperature measurements with ground-based geometric albedo determinations, phase integrals of 0.91 plus or minus 0.13 and 0.89 plus or minus 0.09 were derived for Tethys and Enceladus, respectively. The subsolar point temperature of dark material on Iapetus must exceed 110 K. Temperatures (and infrared optical depths) for the A and C rings and for the Cassini division are 69 plus or minus 1 K (0.40 plus or minus 0.05), 85 plus or minus 1 K (0.10 plus or minus 0.03), and 85 plus or minus 2 K (0.07 plus or minus 0.04), respectively.

  15. Infrared observations of the saturnian system from voyager 2.

    PubMed

    Hanel, R; Conrath, B; Flasar, F M; Kunde, V; Maguire, W; Pearl, J; Pirraglia, J; Samuelson, R; Cruikshank, D; Gautier, D; Gierasch, P; Horn, L; Ponnamperuma, C

    1982-01-29

    During the passage of Voyager 2 through the Saturn system, infrared spectral and radiometric data were obtained for Saturn, Titan, Enceladus, Tethys, Iapetus, and the rings. Combined Voyager 1 and Voyager 2 observations of temperatures in the upper troposphere of Saturn indicate a seasonal asymmetry between the northern and southern hemispheres, with superposed small-scale meridional gradients. Comparison of high spatial resolution data from the two hemispheres poleward of 60 degrees latitude suggests an approximate symmetry in the small-scale structure, consistent with the extension of a symmetric system of zonal jets into the polar regions. Longitudinal variations of 1 to 2 K are observed. Disk- averaged infrared spectra of Titan show little change over the 9-month interval between Voyager encounters. By combining Voyager 2 temperature measurements with ground-based geometric albedo determinations, phase integrals of 0.91 +/- 0.13 and 0.89 +/- 0.09 were derived for Tethys and Enceladus, respectively. The subsolar point temperature of dark material on Iapetus must exceed 110 K. Temperatures (and infrared optical depths) for the A and C rings and for the Cassini division are 69 +/- 1 K (0.40 +/- 0.05), 85 +/- 1 K (0.10 +/- 0.03), and 85 +/- 2 K (0.07 +/- 0.04), respectively.

  16. Near-infrared IFU and MOS observations of supernova remnants

    NASA Astrophysics Data System (ADS)

    Lee, Ho-Gyu

    2016-06-01

    We present near-infrared IFU and MOS observations of two bright [Fe II] line emitting supernova remnants (SNRs). The two SNRs, G11.2-0.3 and RCW103, are selected from our near-infrared [Fe II] 1.64 um narrow band imaging survey of SNRs such as UKIRT unbiased [Fe II] imaging survey of the the Galactic plane and AAT [Fe II] imaging of some core-collapse SNRs. We detect several near-infrared hyperfine lines of [Fe II] at the southeastern shell of G11.2-0.3. We estimate the line strength and extinction-corrected density, which gives a clue to the origin of the iron-rich southeastern shell of G11.2-0.3. We obtain the MOS spectra of [Fe II]-emitting clumps inside RCW103. The observed clumps move about hundreds kilometers in radial direction, suggesting that they are shocked dense materials lost by stellar wind at the final stage of the evolution of the progenitor star.

  17. Fault detection for linear distributed-parameter systems using finite-dimensional functional observers

    NASA Astrophysics Data System (ADS)

    Deutscher, Joachim

    2016-03-01

    In this article, finite-dimensional residual generators are directly designed for Riesz-spectral systems with bounded input and output operators to detect faults. This is achieved by using finite-dimensional observers, that can estimate linear functionals of the state without spillover. These observers allow for a decoupling of the unknown disturbances from the estimation error dynamics under mild assumptions. Then, a finite-dimensional residual generator is obtained by approximately decoupling the state from the residual, that is generated by the observer states and the outputs. It is shown that the resulting approximation error can be made small by increasing the observer order. Then, fault detection with the finite-dimensional residual generator can be assured by introducing a time-varying threshold. A faulty Euler-Bernoulli beam with structural damping illustrates the proposed finite-dimensional fault detection approach.

  18. Thermal Infrared Observations and Thermophysical Modeling of Phobos

    NASA Astrophysics Data System (ADS)

    Smith, Nathan Michael; Edwards, Christopher Scott; Mommert, Michael; Trilling, David E.; Glotch, Timothy

    2016-10-01

    Mars-observing spacecraft have the opportunity to study Phobos from Mars orbit, and have produced a sizeable record of observations using the same instruments that study the surface of the planet below. However, these observations are generally infrequent, acquired only rarely over each mission.Using observations gathered by Mars Global Surveyor's (MGS) Thermal Emission Spectrometer (TES), we can investigate the fine layer of regolith that blankets Phobos' surface, and characterize its thermal properties. The mapping of TES observations to footprints on the Phobos surface has not previously been undertaken, and must consider the orientation and position of both MGS and Phobos, and TES's pointing mirror angle. Approximately 300 fully resolved observations are available covering a significant subset of Phobos' surface at a variety of scales.The properties of the surface regolith, such as grain size, density, and conductivity, determine how heat is absorbed, transferred, and reradiated to space. Thermophysical modeling allows us to simulate these processes and predict, for a given set of assumed parameters, how the observed thermal infrared spectra will appear. By comparing models to observations, we can constrain the properties of the regolith, and see how these properties vary with depth, as well as regionally across the Phobos surface. These constraints are key to understanding how Phobos formed and evolved over time, which in turn will help inform the environment and processes that shaped the solar system as a whole.We have developed a thermophysical model of Phobos adapted from a model used for unresolved observations of asteroids. The model has been modified to integrate thermal infrared flux across each observed portion of Phobos. It will include the effects of surface roughness, temperature-dependent conductivity, as well as radiation scattered, reflected, and thermally emitted from the Martian surface. Combining this model with the newly-mapped TES

  19. Spitzer Infrared Spectrograph Observations of L, M, and T Dwarfs

    NASA Technical Reports Server (NTRS)

    Roellig, Thomas L.; VanCleve, Jeffrey E.; Sloan, Gregory C.; Wilson, John C.; Saumon, Didier; Leggett, Sandy K.; Marley, Mark S.; Cushing, Michael; Kirkpatrick, J. Davy; Mainzer, Amanda K.

    2004-01-01

    We present here the first mid-infriared spectra of brown dwarfs, together with observations of a low-mass star. Our targets are the M3.5 dwarf GJ 1001 A, the L8 dwarf DENIS-P JO255-4700, and the T1/T6 binary system epsilon Indi Ba/Bb. As expected, the mid- infrared spectral morphology of these objects changes rapidly with spectral class due to the changes in atmospheric chemistry resulting from their differing effective temperatures and atmospheric structures. By taking advantage of the unprecedented sensitivity of the Infrared Spectrograph instrument of the Spitzer Space Telescope we have detected for the first time the 7.6 micron methane band and confirmed the presence of ammonia in a T dwarf atmosphere.

  20. Infrared properties of dust grains derived from IRAS observations

    NASA Technical Reports Server (NTRS)

    Chlewicki, G.; Laureijs, R. J.; Clark, I. O.; Wesselius, P. R.

    1987-01-01

    The analysis of several diffuse interstellar clouds observed by the Infrared Astronomy Satellite (IRAS) is presented. The 60/100 micron flux ratios appear to be nearly constant in clouds with up to 1 sup m visual extinction at the center. Observations of a highly regular cloud in Chamaeleon show that the 12/100 micron ratio peaks at an intermediate radial distance and declines towards the center of the cloud. These observations indicate that nonequilibrium emission accounts only for the 12 and 25 micron bands; strong emission observed at the 60 micron band is probably due to equilibrium thermal radiation. The correlation of the 12 micron emission with a red excess observed for a high latitude cloud, L1780, is shown to be consistent with the assumption that both features are due to fluorescence by the same molecular species.

  1. Visible and Near Infrared Spectroscopic and Spectrophotometric Observations of NEOs

    NASA Astrophysics Data System (ADS)

    de Leon Cruz, J.; Licandro, J.; Serra-Ricart, M.

    2003-05-01

    In august 2002 we started an observational program to obtain physical information of a significant number of Near Earth Objects by means of simultaneous visible and near infrared spectroscopy and spectrophotometry using telescope facilities of Teide and El Roque de los Muchachos Observatories (Canary Islands, Spain). Near infrared spectroscopy is done using the 3.5-m TNG telescope with the NICS camera-spectrograph and its low resolution Amici prism disperser (Licandro et al. 2001, A&A 373, 29L). Visible spectroscopy is done using the 2.5-m NOT telescope with the ALFOSC camera-spectrograph. At present we have some spectra taken with both telescopes, and 4 nights schedulled for simultaneous observations next semester. Simultaneous visible and near-infrared photometry is done using the CCD camera attached to the 80-cm IAC80 telescope and B,V,R,I filters, and the 1.5-m Carlos Sanchez Telescope with CAIN camera (Nicmos 256x256 array) and J,H,K filters. Until this moment we have spent almost 50 nights for the photometric program, and schedulled 4 nights per month next semester. Our spectral analysis at visible wavelengths of these objects uses some of the techniques and taxonomic system developed by Bus (1999, PhD thesis), studying the presence or absence of specific spectral features in their reflectance spectra. In addition, near infrared spectra obtained for a number of NEOs enhances the compositional interpretation of our sample. Broad band spectrophotometric colors also provide low resolution spectra that can be compared with taxonomic classes defined by Tholen (1984, PhD Thesis). We also compare our spectral data with laboratory measurements of meteorites (Gaffey 1976, JGR 81,905) in order to stablish a possible link between main belt asteroids, near-Earth objects and meterorites, and to detect the effects of space weathering in the surface composition of our objects. A description of the program and preliminary results is presented.

  2. Solar System Observing with the Space Infrared Telescope Facility (SIRTF)

    NASA Technical Reports Server (NTRS)

    Cleve, J. Van; Meadows, V. S.; Stansberry, J.

    2003-01-01

    SIRTF is NASA's Space Infrared Telescope Facility. Currently planned for launch on 15 Apr 2003, it is the final element in NASA's Great Observatories Program. SIRTF has an 85 cm diameter f/12 lightweight beryllium telescope, cooled to lekss than 5.5K. It is diffraction-limited at 6.5 microns, and has wavelengthcoverage from 3-180 microns. Its estimated lifetime (limited by cryogen) is 2.5 years at minimum, with a goal of 5+ years. SIRTF has three instruments, IRAC, IRS, and MIPS. IRAC (InfraRed Array Camera) provides simultaneous images at wavelengths of 3.6, 4.5, 5.8, and 8.0 microns. IRS (InfraRed Spectrograph) has 4 modules providing low-resolution (R=60-120) spectra from 5.3 to 40 microns, high-resolution (R=600) spectra from 10 to 37 microns, and an autonomous target acquisition system (PeakUp) which includes small-field imaging at 15 microns. MIPS (Multiband Imaging Photometer for SIRTF)} does imaging photometry at 24, 70, and 160 m and low-resolution (R=15-25) spectroscopy (SED) between 55 and 96 microns. The SIRTF Guaranteed Time Observers (GTOs) are planning to observe Outer Solar System satellites and planets, extinct comets and low-albedo asteroids, Centaurs and Kuiper Belt Objects, cometary dust trails, and a few active short-period comets. The GTO programs are listed in detail in the SIRTF Reserved Observations Catalog (ROC). We would like to emphasize that there remain many interesting subjects for the General Observers (GO). Proposal success for the planetary observer community in the first SIRTF GO proposal cycle (GO-1) determines expectations for future GO calls and Solar System use of SIRTF, so we would like promote a strong set of planetary GO-1 proposals. Towards that end, we present this poster, and we will convene a Solar System GO workshop 3.5 months after launch.

  3. Far infrared supplement. Third edition: Catalog of infrared observations (lambda greater than or equal to 4.6 micrometers)

    NASA Technical Reports Server (NTRS)

    Gezari, Daniel Y.; Schmitz, Marion; Pitts, Patricia S.; Mead, Jaylee M.

    1993-01-01

    The Far Infrared Supplement contains a subset of the data in the full Catalog of Infrared Observations (all observations at wavelengths greater than 4.6 microns). The Catalog of Infrared Observations (CIO), NASA RP-1294, is a compilation of infrared astronomical observational data obtained from an extensive literature search of scientific journals and major astronomical catalogs and surveys. The literature search is complete for years 1965 through 1990 in this third edition. The catalog contains about 210,000 observations of roughly 20,000 individual sources, and supporting appendices. The expanded third edition contains coded IRAS 4-band data for all CIO sources detected by IRAS. The appendices include an atlas of infrared source positions (also included in this volume), two bibliographies of catalog listings, and an atlas of infrared spectral ranges. The complete CIO database is available to qualified users in printed, microfiche, and magnetic tape formats.

  4. Far infrared supplement. Third edition: Catalog of infrared observations (lambda greater than or equal to 4.6 micrometers)

    NASA Astrophysics Data System (ADS)

    Gezari, Daniel Y.; Schmitz, Marion; Pitts, Patricia S.; Mead, Jaylee M.

    1993-06-01

    The Far Infrared Supplement contains a subset of the data in the full Catalog of Infrared Observations (all observations at wavelengths greater than 4.6 microns). The Catalog of Infrared Observations (CIO), NASA RP-1294, is a compilation of infrared astronomical observational data obtained from an extensive literature search of scientific journals and major astronomical catalogs and surveys. The literature search is complete for years 1965 through 1990 in this third edition. The catalog contains about 210,000 observations of roughly 20,000 individual sources, and supporting appendices. The expanded third edition contains coded IRAS 4-band data for all CIO sources detected by IRAS. The appendices include an atlas of infrared source positions (also included in this volume), two bibliographies of catalog listings, and an atlas of infrared spectral ranges. The complete CIO database is available to qualified users in printed, microfiche, and magnetic tape formats.

  5. Thermal analysis of fused deposition modeling process using infrared thermography imaging and finite element modeling

    NASA Astrophysics Data System (ADS)

    Zhou, Xunfei; Hsieh, Sheng-Jen

    2017-05-01

    After years of development, Fused Deposition Modeling (FDM) has become the most popular technique in commercial 3D printing due to its cost effectiveness and easy-to-operate fabrication process. Mechanical strength and dimensional accuracy are two of the most important factors for reliability of FDM products. However, the solid-liquid-solid state changes of material in the FDM process make it difficult to monitor and model. In this paper, an experimental model was developed to apply cost-effective infrared thermography imaging method to acquire temperature history of filaments at the interface and their corresponding cooling mechanism. A three-dimensional finite element model was constructed to simulate the same process using element "birth and death" feature and validated with the thermal response from the experimental model. In 6 of 9 experimental conditions, a maximum of 13% difference existed between the experimental and numerical models. This work suggests that numerical modeling of FDM process is reliable and can facilitate better understanding of bead spreading and road-to-road bonding mechanics during fabrication.

  6. Observable measure of quantum coherence in finite dimensional systems.

    PubMed

    Girolami, Davide

    2014-10-24

    Quantum coherence is the key resource for quantum technology, with applications in quantum optics, information processing, metrology, and cryptography. Yet, there is no universally efficient method for quantifying coherence either in theoretical or in experimental practice. I introduce a framework for measuring quantum coherence in finite dimensional systems. I define a theoretical measure which satisfies the reliability criteria established in the context of quantum resource theories. Then, I present an experimental scheme implementable with current technology which evaluates the quantum coherence of an unknown state of a d-dimensional system by performing two programmable measurements on an ancillary qubit, in place of the O(d2) direct measurements required by full state reconstruction. The result yields a benchmark for monitoring quantum effects in complex systems, e.g., certifying nonclassicality in quantum protocols and probing the quantum behavior of biological complexes.

  7. Juno/JIRAM infrared observations of Jupiter Aurorae

    NASA Astrophysics Data System (ADS)

    Mura, Alessandro; Adriani, Alberto; Altieri, Francesca; Dinelli, Bianca Maria; Moriconi, Maria Luisa; Migliorini, Alessandra; Bolton, Scott J.; Connerney, Jack E. P.; Atreya, Sushil; Bagenal, Fran; Gladstone, Randy; Hansen-Koharcheck, Candy; Kurth, William S.; Levin, Steven M.; Lunine, Jonathan; Mauk, Barry H.; McComas, David J.; Amoroso, Marilena

    2017-04-01

    The Jovian Infrared Auroral Mapper (JIRAM) is an imager/spectrometer to study the jovian aurorae on board the NASA mission Juno. Jupiter's aurorae, the most powerful among the planets in the Solar System, are the results of high-energy electrons falling along the planet's magnetic field lines into the upper atmosphere, exciting the atmospheric gases, which then emit at different wavelengths. JIRAM, specifically, is designed to observe the intense emission of H3+, which is mainly possible in a spectral interval (3.2 to 4.0 μm) where the solar and thermal radiance emitted by the planet is very low due to intense atmospheric methane absorption band, resulting in high auroral contrast against Jupiter's dark disk. Hence, JIRAM is composed of two IR imager channels and one spectrometer in the range 2-5 um, with a spectral resolution of less than 10 nm and surface resolution as low as 50 km. One of the two imager channels is centered at 3.455 μm (in the H3+ emission region), to give a context information of auroral emission, for better understanding the spectrometer detailed measurement. In this presentation we show latest results on JIRAM's observations of the H3+ infrared emission. Taking advantage of optimal point of view given by the polar orbit of the Juno spacecraft, these observations provide spatial, spectral and temporal distribution of the Jovian auroras; the footprints of Io, Europa and Ganymede are also observed and studied.

  8. Infrared Observations of SO emission from Io's Atmosphere during Eclipse

    NASA Astrophysics Data System (ADS)

    de Kleer, K.; De Pater, I.; Adamkovics, M.

    2013-12-01

    Io, the volcanic moon of Jupiter, hosts an atmosphere dominated by SO2 and SO, but the question of the direct source of these molecules is still debated. Many different approaches have been taken to establish a link between volcanic activity on Io and atmospheric effects, to distinguish whether the atmosphere is supplied by volcanic outgassing or ice sublimation. In the infrared, atmospheric emission lines are lost in reflected sunlight; observing Io in eclipse provides a unique opportunity to study infrared lines, during a time when most of Io's atmosphere may be frozen out in Jupiter's shadow. In 1999 the a1Δ → Χ3Σ- transition of SO at 1.707 μm was discovered by de Pater et al. (2002); Laver et al. (2007) made additional observations, which they fit with equilibrium models to infer a likely volcanic origin for the SO. Here we present additional high spectral resolution observations of the 1.707 μm SO line while Io is in eclipse. We model these observations with equilibrium and non-LTE models, and address implications for the origin of SO on Io.

  9. Infrared Spectral Observations While Drilling into a Frozen Lunar Simulant

    NASA Technical Reports Server (NTRS)

    Roush, Ted L.; Colaprete, Anthony; Thompson, Sarah; Cook, Amanda; Kleinhenz, Julie

    2014-01-01

    Past and continuing observations indicate an enrichment of volatile materials in lunar polar regions. While these volatiles may be located near the surface, access to them will likely require subsurface sampling, during which it is desirable to monitor the volatile content. In a simulation of such activities, a multilayer lunar simulant was prepared with differing water content, and placed inside a thermal vacuum chamber at Glenn Research Center (GRC). The soil profile was cooled using liquid nitrogen. In addition to the soil, a drill and infrared (IR) spectrometer (1600-3400 nm) were also located in the GRC chamber. We report the spectral observations obtained during a sequence where the drill was repeatedly inserted and extracted, to different depths, at the same location. We observe an overall increase in the spectral signature of water ice over the duration of the test. Additionally, we observe variations in the water ice spectral signature as the drill encounters different layers.

  10. The diffuse infrared background - COBE and other observations

    NASA Technical Reports Server (NTRS)

    Hauser, M. G.; Kelsall, T.; Moseley, S. H., Jr.; Silverberg, R. F.; Murdock, T.; Toller, G.; Spiesman, W.; Weiland, J.

    1991-01-01

    The Diffuse Infrared Background Experiment (DIRBE) on the Cosmic Background Explorer (COBE) satellite is designed to conduct a sensitive search for an isotropic cosmic infrared background radiation over the spectral range from 1 to 300 micrometers. The cumulative emissions of pregalactic, protogalactic, and evolving galactic systems are expected to be recorded in this background. The DIRBE instrument, a 10 spectral band absolute photometer with an 0.7 deg field of view, maps the full sky with high redundancy at solar elongation angles ranging from 64 to 124 degrees to facilitate separation of interplanetary, Galactic, and extragalactic sources of emission. Initial sky maps show the expected character of the foreground emissions, with relative minima at wavelengths of 3.4 micrometers and longward of 100 micrometers. Extensive modelling of the foregrounds, just beginning, will be required to isolate the extragalactic component. In this paper, we summarize the status of diffuse infrared background observations from the DIRBE, and compare preliminary results with those of recent rocket and satellite instruments.

  11. Small particle cirrus observed by the Atmospheric Infrared Sounder

    NASA Astrophysics Data System (ADS)

    Kahn, B. H.; Eldering, A.; Fishbein, E. F.

    2003-04-01

    The high-resolution spectra of the Atmospheric Infrared Sounder (AIRS) have provided an opportunity to globally observe small particle-dominated cirrus clouds. The shape of the radiance spectra in the atmospheric windows is uniquely influenced by small ice crystals with an effective radius (reff) of a few 10s of microns and smaller. In some rare instances, minima in the AIRS brightness temperature (BT) spectra between 800 to 850 cm-1 are seen, consistent with the existence of ice particles with an reff smaller than 3 microns. Much more frequent occurences of small ice particle clouds with reff larger than 3 microns are observed through the large 998 to 811 cm-1 BT differences without minima. The small particle events are occasionally found in orographic cirrus clouds, in and around cumulonimbus towers, and in cirrus bands far removed from convection and orography. Several cases spanning the variety of small particle-dominated cirrus events will be presented. AIRS, located on the EOS-Aqua platform, is a high-resolution grating spectrometer that scans at angles 49.5 degrees on either side of nadir view, at both visible and infrared wavelengths. The surface footprint is 13.5 km at the nadir view, and coverage in the infrared is in three bandpasses (649-1136, 1265-1629, and 2169-2674 cm-1). Comparisons of observed spectra are made with simulated spectra generated by a plane-parallel scattering radiative transfer model using ice particle shapes and sizes calculated by the T-matrix method. These comparisons yield information on small particle cirrus cloud reff and optical depth. Aumann, H.H., and R.J. Pagano, Atmospheric Infrared Sounder on the Earth Observing System. Opt. Eng. 33, 776-784, 1994. Mishchenko, M.I., and L.D. Travis, Capabilities and limitations of a current Fortran implementation of the T-matrix method for randomly oriented, rotationally symmetric scatterers. J. Quant. Spectrosc. Radiat. Transfer, 60, 309-324, 1998. Moncet, J.L., and S.A. Clough

  12. Infrared Algorithm Development for Ocean Observations with EOS/MODIS

    NASA Technical Reports Server (NTRS)

    Brown, Otis B.

    1997-01-01

    Efforts continue under this contract to develop algorithms for the computation of sea surface temperature (SST) from MODIS infrared measurements. This effort includes radiative transfer modeling, comparison of in situ and satellite observations, development and evaluation of processing and networking methodologies for algorithm computation and data accession, evaluation of surface validation approaches for IR radiances, development of experimental instrumentation, and participation in MODIS (project) related activities. Activities in this contract period have focused on radiative transfer modeling, evaluation of atmospheric correction methodologies, undertake field campaigns, analysis of field data, and participation in MODIS meetings.

  13. Infrared algorithm development for ocean observations with EOS/MODIS

    NASA Technical Reports Server (NTRS)

    Brown, Otis B.

    1994-01-01

    Efforts continue under this contract to develop algorithms for the computation of sea surface temperature (SST) from MODIS infrared retrievals. This effort includes radiative transfer modeling, comparison of in situ and satellite observations, development and evaluation of processing and networking methodologies for algorithm computation and data accession, evaluation of surface validation approaches for IR radiances, and participation in MODIS (project) related activities. Efforts in this contract period have focused on radiative transfer modeling and evaluation of atmospheric path radiance efforts on SST estimation, exploration of involvement in ongoing field studies, evaluation of new computer networking strategies, and objective analysis approaches.

  14. Io Science Opportunities with JIMO: Observing in the Infrared

    NASA Technical Reports Server (NTRS)

    Smythe, W. D.; Lopes, R.; Spencer, J. R.

    2003-01-01

    The Jupiter Icy Moons Orbiter presents an opportunity to greatly improve our understanding of the most dynamic body in the solar system. Io is the best place to study tidal heating of the Galilean moons, provides unique insights into Earth history and is a unique laboratory for basic planetary physics. Many important questions about Io remain after Galileo that cannot be addressed from Earth or Earth orbit, but could be answered by limited observing time from JIMO with the appropriate instrumentation. Here we outline the requirements in the infrared.

  15. 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.

  16. Infrared Observations of the Thermal Emission from the Corona

    NASA Astrophysics Data System (ADS)

    Mampaso, A.; Sanchez-Magro, C.; Selby, M. J.; MacGregor, A. D.

    1983-06-01

    During the summer of 1978 the F Corona was observed from the ground in the near infrared at 2. and 3. in an attempt to measure the localized thermal emission from dust predicted by Peterson (1963) and several other workers. We failed to detect this emission even though our experimental errors were well below previously quoted emission values. If thermal emission peaks around the sun exist, we believe they are either much weaker or have different shapes compared to previous ones found. This result, if confirmed, will require a revision of the dynamics and physics of circumsolar dust.

  17. Spectrally resolved infrared radiances from AIRS observation and GCM simulation

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Ramaswamy, V.

    2007-12-01

    Global multi-year spectrally resolved infrared radiances observed by the Atmospheric Infrared Sound (AIRS) satellite instrument and simulated from the General Circulation Models (GCMs) of the Geophysical Fluid Dynamics Lab (GFDL) are processed to obtain long-term global and regional means as well as the associated spatial and temporal variability. The accumulated radiance data comprise a host of phenomena that are still largely unrecognized but reveal important physical processes. For instance, the correlation between the radiances and the Sea Surface Temperatures (SSTs) discloses the roles of water vapor in both upper (via its v2 band) and lower (via the continuum in the window region) troposphere, and that of clouds regarding the so called "super greenhouse effect" in Tropics. A comparison between observed and simulated radiances demonstrates that radiance affords a stricter and more insightful metric than the broadband flux. A seemingly good agreement of OLR flux may arise from cancellation of errors of opposite signs in different spectral regions; radiance biases are indicative of physical causes because the radiances at each frequency are sensitive to factor(s) at different levels. Model validation at the radiance level thus provides a complementary and integrative perspective to that obtained using meteorological variables. It is demonstrated that the radiance discrepancies between the GFDL model and the observation are consistent with the model biases in temperature, water vapor and clouds.

  18. Robust control of post-stall pitching maneuver based on finite-time observer.

    PubMed

    Wu, Dawei; Chen, Mou; Gong, Huajun

    2017-09-01

    This article presents a robust finite-time maneuver control scheme for the longitudinal attitude dynamic of the aircraft with unsteady aerodynamic disturbances and input saturation. To efficiently eliminate the influence of unsteady aerodynamic disturbances, nonlinear finite-time observers are developed. Despite the existence of the nonlinearity and the coupling between aircraft states and unsteady aerodynamic disturbances, the proposed observers can still precisely estimate the unmeasurable unsteady aerodynamic disturbances in finite time. To attenuate the effect caused by input saturation, a finite-time auxiliary system is constructed. With the error between the desired control input and saturation input as the input of the auxiliary system, the additional signals are generated to compensate for the effect of input saturation. Combined with the finite-time observers and the finite-time auxiliary system, a robust finite-time backstepping attitude control design is developed. The finite-time convergence of all closed-loop system signals is rigorously proved via Lyapunov analysis method under the developed robust attitude control schemes. Finally, simulation results are presented to illustrate the effectiveness of the proposed attitude control approaches. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  19. The nature of cometary dust as determined from infrared observations

    NASA Technical Reports Server (NTRS)

    Swamy, K. S. Krishna; Sandford, Scott A.; Allamandola, Louis J.; Witteborn, Fred C.; Bregman, Jesse D.

    1989-01-01

    The infrared measurements of comets, the compositional information available from interplanetary dust particles (IDPs), and the recent results of flybys to Comet Halley can help in restricting the nature and composition of cometary dust models (c.f., Proceedings of the 20th ESLAB Symposium on Exploration of Halley's Comet, 1986). Researchers tried to incorporate some of these results into a coherent model to account for the observed cometary infrared emission. The presence of 10 and 3.4 micron features in Comet Halley (c.f. Bregman et al. 1987; Wickramasinghe and Allen 1986) indicated the presence of at least two components in the grain material, namely silicates and some form of amorphous carbon. These two components could reside in separate grains or may be parts of composite particles. Both these cases have been considered (see Krishna Swamy el a. 1988a, 1988b). In the absence of refractive index data for cometary analogs, the authors used the optical constants of olivine-rich lunar material 12009.48 (Perry et al. 1972) for the infrared region and that of alpha:C-H film for amorphous carbon (angus et al. 1986). For the visible region, a value of m = 1.38-0.39i was used for the silicates, and values published by Arakawa et al. (1985) were used for the amorphous carbon. These materials should give a representative behavior of the expected results. The model results were compared to observational data. The strength of the 3.4 micron and 10 micron features relative to the adjacent continuum, as well as the slope of the continuum between 2500 and 1250 cm(exp -1) (4 to 8 microns), were used as criteria for comparison. Model calculations with alpha approx. equals -3.5, and also the size distribution function inferred for Comet Halley, with a mass fraction (X) of silicate to amorphous carbon grains of about 40 to 1 can fit the data. A good match is obtained for the infrared spectra of Comets Halley and West from a 40 to 1 mixture of silicate and amorphous carbon grains

  20. The NASA Infrared Telescope Facility (IRTF): New Observational Capabilities

    NASA Astrophysics Data System (ADS)

    Tokunaga, Alan T.; Bus, S. J.; Connelley, Michael S.; Rayner, John T.

    2015-11-01

    The NASA Infrared Telescope Facility (IRTF) is a 3.0-m infrared telescope located at an altitude of 4.2 km near the summit of Mauna Kea on the island of Hawaii. The IRTF was established by NASA to support planetary science missions. Current instruments include: (1) SpeX, a 0.7-5.3 μm moderate resolution spectrograph with a slit-viewing camera that is also an imager, (2) MORIS, a high-speed CCD imager attached to SpeX for simultaneous visible and near-infrared observations, and (3) CSHELL, a 1-5 μm high-resolution spectrograph. MORIS can also be used as a visible wavelength guider for SpeX. Detector upgrades have recently been made to SpeX. We discuss new observational capabilities resulting from completion of a new echelle spectrograph for 1-5 μm with resolving power of 70,000 with a 0.375 arcsec slit. This instrument will be commissioned starting in the spring of 2016. We also plan to restore to service our 8-25 μm camera, MIRSI. It will be upgraded with a closed-cycle cooler that will eliminate the need for liquid helium and allow continuous use of MIRSI on the telescope. This will enable thermal observations of NEOs on short notice. We also plan to upgrade MIRSI to have a simultaneous visible imager for guiding and for photometry. The IRTF supports remote observing from any site. This eliminates the need for travel to the observatory and short observing time slots can be supported. We also welcome onsite visiting astronomers. In the near future we plan to implement a low-order wave-front sensor to allow real-time focus and collimation of the telescope. This will greatly improve observational efficiency. For further information on the IRTF and its instruments including visitor instruments, see: http://irtfweb.ifa.hawaii.edu/. We gratefully acknowledge the support of NASA contract NNH14CK55B, NASA Science Mission Directorate.

  1. Infrared Observations During the Secondary Eclipse of HD209458b

    NASA Astrophysics Data System (ADS)

    Richardson, L. J.; Deming, D.; Wiedemann, G.; Goukenleuque, C.; Esposito, L. W.; Harrington, J.

    2001-11-01

    We discuss the status of our observational program to detect infrared radiation from the "transiting planet," HD209458b. Current models suggest that the planet could be as hot as 1400K, with a significant infrared output in spectral bands having minimum water vapor opacity. Our differential spectroscopic technique is designed to detect the subtle change in the 2-4 micron spectrum as the planet is blocked by the star during secondary eclipse. We have observed the system during three secondary eclipse events: two in July 2001 using ISAAC at the VLT (3.5-3.7 microns, R=3300) and one in September 2001 using the SpeX instrument at the IRTF (1.9-4.2 microns, R=1500). Analysis of these extensive data is in progress. Although direct detection of the planet is not guaranteed, initial examination of the data lead us to be optimistic concerning the utility of our differential spectroscopic approach. This work is sponsored by NASA's Origins of Solar Systems Program and by a NASA GSRF Fellowhsip to L.J.R.

  2. Infrared observations during the secondary eclipse of HD209458b

    NASA Astrophysics Data System (ADS)

    Richardson, L. J.; Deming, D.; Wiedemann, G.; Goukenleuque, C.; Esposito, L. W.; Harrington, J.

    2001-12-01

    We discuss the status of our observational program to detect infrared radiation from the "transiting planet," HD209458b. Current models suggest that the planet could be as hot as 1400K, with a significant infrared output in spectral bands having minimum water vapor opacity. Our differential spectroscopic technique is designed to detect the subtle change in the 2-4 micron spectrum as the planet is blocked by the star during secondary eclipse. We have observed the system during four secondary eclipse events: two in July 2001 using ISAAC at the VLT (3.5-3.7 microns, R=3300) and two in September 2001 using the SpeX instrument at the IRTF (1.9-4.2 microns, R=1500). Analysis of these extensive data is in progress. Although direct detection of the planet is not guaranteed, initial examination of the data lead us to be optimistic concerning the utility of our differential spectroscopic approach. This work is sponsored by NASA's Origins of Solar Systems Program and by a NASA GSRP Fellowship to L.J.R.

  3. 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.

  4. Using near infrared light for deep sea mining observation systems

    NASA Astrophysics Data System (ADS)

    Lu, Huimin; Li, Yujie; Li, Xin; Yang, Jianmin; Serikawa, Seiichi

    2015-10-01

    In this paper, we design a novel deep-sea near infrared light based imaging equipment for deep-sea mining observation systems. The spectral sensitivity peaks are in the red region of the invisible spectrum, ranging from 750nm to 900nm. In addition, we propose a novel underwater imaging model that compensates for the attenuation discrepancy along the propagation path. The proposed model fully considered the effects of absorption, scattering and refraction. We also develop a locally adaptive Laplacian filtering for enhancing underwater transmission map after underwater dark channel prior estimation. Furthermore, we propose a spectral characteristic-based color correction algorithm to recover the distorted color. In water tank experiments, we made a linear scale of eight turbidity steps ranging from clean to heavily scattered by adding deep sea soil to the seawater (from 500 to 2000 mg/L). We compared the results of different turbidity underwater scene, illuminated alternately with near infrared light vs. white light. Experiments demonstrate that the enhanced NIR images have a reasonable noise level after the illumination compensation in the dark regions and demonstrates an improved global contrast by which the finest details and edges are significantly enhanced. We also demonstrate that the effective distance of the designed imaging system is about 1.5 meters, which can meet the requirement of micro-terrain observation around the deep-sea mining systems. Remotely Operated Underwater Vehicle (ROV)-based experiments also certified the effectiveness of the proposed method.

  5. NOVEL OBSERVATIONS AND POTENTIAL APPLICATIONS USING DIGITAL INFRARED IRIS IMAGING

    PubMed Central

    Roberts, Daniel K.; Lukic, Ana; Yang, Yongyi; Moroi, Sayoko E.; Wilensky, Jacob T.; Wernick, Miles N.

    2017-01-01

    Digital infrared (IR) iris photography using a modified digital camera system was carried out on about 300 subjects seen during routine clinical care and research at one facility. Since this image database offered opportunity to gain new insight into the potential utility of IR iris imaging, it was surveyed for unique image patterns. Then, a selection of photos was compiled that would illustrate the spectrum of this imaging experience. Potentially informative image patterns were observed in subjects with cataracts, diabetic retinopathy, Posner-Schlossman syndrome, iridociliary cysts, long anterior lens zonules, nevi, oculocutaneous albinism, pigment dispersion syndrome, pseudophakia, suspected vascular anomaly, and trauma. Image patterns were often unanticipated regardless of pre-existing information and suggest that IR iris imaging may have numerous potential clinical and research applications, some of which may still not be recognized. These observations suggest further development and study of this technology. PMID:19320317

  6. Voyager infrared observations of Uranus' atmosphere - Thermal structure and dynamics

    NASA Astrophysics Data System (ADS)

    Flasar, F. M.; Conrath, B. J.; Pirraglia, J. A.; Gierasch, P. J.

    1987-12-01

    Temperatures in the Uranus atmosphere are derived from infrared spectrometer (IRIS) observations for a layer between 60 and 200 mbar, which includes the tropopause, where the vertical profile of temperature has a minimum. The variation with latitude of these temperatures and the implied thermal winds are in the same sense as those previously reported at the lower altitude range. The authors discuss the implications of this for dynamical models of the atmospheric thermal and wind structure. Finally, they use a linear, zonally symmetric model with radiative damping and frictional drag to estimate the magnitude of the frictional damping that is needed to account for the tropopause temperatures derived from IRIS observations and the zonal winds inferred from Voyager imaging data.

  7. Infrared and Submillimeter Observations Of IRAS 03245+3002

    NASA Astrophysics Data System (ADS)

    Doney, Kirstin D.; Kim, H.; Evans, N. J.

    2012-01-01

    We present a study of a young stellar object in the embedded phase, IRAS 03245+3002, which is part of the Dust, Ice, and Gas In Time (DIGIT) project which is designed to span the full range Lbol-Tbol diagram. The Spitzer Space Telescope and ground-based telescopes, 2MASS and CSO, have observed the object in the infrared and submillimeter wavelengths. The photometric data give constraints on the radiative transfer modeling and give an bolometric luminosity of 4.6L⊙. We also present the molecular line observations of six species toward IRAS 03245+3002 taken at CSO, the molecular line modeling, of which are still on going, will give an expectation of the molecular abundances of the source and will be presented in the poster. I would like to acknowledge Dr. Neal J. Evans II, Hyo Jeong Kim, and the University of Texas at Austin for their help and support.

  8. Further radio observations of IRAS extreme infrared galaxies

    NASA Astrophysics Data System (ADS)

    Antonucci, R. R. J.; Olszewski, E. W.

    1986-01-01

    Aaronson and Olszewski (1984) have identified five IRAS infrared sources, previously considered to be blank fields, with faint galaxies. The authors reported previously the results of their VLA D-array observations at 6 cm (Antonucci and Olszewski, 1985), which resulted in detections of all objects at the mJy level. The sources were unresolved by the ≡16 arcsec beam. The present paper reports on B-array observations at 6 and 20 cm, made in order to determine or limit the source angular sizes, and to measure the spectral indices. The source 0358+223 has an angular size of ≡3 arcsec at 20 cm, but no redshift is available for this object; also 0404+101 is marginally resolved at 20 cm. The other sources are unresolved by the ≡1.1 arcsec resolution deep 6 cm maps, implying linear sizes <2 kpc. The spectra are steep, indicating that the radiation mechanism is optically thin synchrotron emission.

  9. Near-infrared observations of IRAS minisurvey galaxies

    NASA Technical Reports Server (NTRS)

    Carico, David P.; Soifer, B. T.; Elias, J. H.; Matthews, K.; Neugebauer, G.; Beichman, C.; Persson, C. J.; Persson, S. E.

    1987-01-01

    Near infrared photometry at J, H, and K was obtained for 82 galaxies from the IRAS minisurvey. The near infrared colors of these galaxies cover a larger range in J-H and H-K than do normal field spiral galaxies, and evidence is presented of a tighter correlation between the near and far infrared emission in far infrared bright galaxies than exists between the far infrared and the visible emission. These results suggest the presence of dust in the far infrared bright galaxies, with hot dust emission contributing to the 2.2 micron emission, and extinction by dust affecting both the near infrared colors and the visible luminosities. In addition, there is some indication that the infrared emission in many of the minisurvey galaxies is coming from a strong nuclear component.

  10. Titan's Seasonal Changes Observed in the Thermal Infrared (Invited)

    NASA Astrophysics Data System (ADS)

    Jennings, D. E.; Anderson, C. M.; Nixon, C. A.; Bjoraker, G. L.; Achterberg, R. K.; Flasar, F.; Cottini, V.; Coustenis, A.; Vinatier, S.; Teanby, N. A.; Bampasidis, G.

    2013-12-01

    A central goal of the Cassini Mission is the detection and tracking of seasonal variations on Titan. Cassini arrived in the Saturn system in late northern winter and has so far observed for almost four Titan months, enough time to see significant changes as solar warming has moved northward. In the thermal infrared the shift has been apparent both in emission from the atmosphere and temperatures at the surface. Gases, clouds and aerosols in the atmosphere warm and cool with the seasons, accumulate and dissipate, and undergo transport on a global scale. Warming of the surface helps drive the exchange of heat and volatiles with the atmosphere, which contributes to weather. Seasonal activity in the north can be expected to be repeated in the south over the course of a year, so that it may be possible by the end of the Cassini Mission to combine winter-spring data from the north and summer-autumn data from the south to build up a picture that covers almost a full annual cycle. The Composite Infrared Spectrometer (CIRS) on Cassini records thermal infrared spectra in the 7-1000 micron range. CIRS has found that surface temperatures at Titan's poles are about 2.5 K lower than near the equator and that the temperatures moved from peaking south of the equator in 2005 to being approximately centered at the equator in 2011. As Titan passed through equinox in 2009, CIRS watched as atmospheric patterns that had been associated with northern winter began to emerge in the south. Emission from stratospheric gases and condensates varied dramatically as temperatures, chemistry and transport configurations adjusted to the season. Complex nitriles that had only been present at high northern latitudes began to appear near the South Pole while a polar ice cloud, originally identified in the north by its spectral emission, made an abrupt debut in the south. We expect much more evidence of seasonal evolution in the thermal infrared as CIRS continues to study Titan through the remainder of

  11. Infrared band strengths: Laboratory techniques and applications to astronomical observations

    NASA Astrophysics Data System (ADS)

    Gerakines, P. A.

    2002-09-01

    Whenever an abundance measurement is derived by way of infrared spectroscopy, it will typically make use of a laboratory-obtained conversion factor between the size of an IR absorption feature and the (column) density of the molecule under study. This factor is usually called the "absolute absorption intensity" by a chemist or the "band strength" by a typical IR astronomer. Band strengths have been studied in chemistry since the 1950s, and the commonly quoted "accuracy to with a factor of ten" historically required of astronomical calculations has not required much new input into this area. Today, however, astronomical measurements require much higher precision, and it is time for IR astronomers to ask more of laboratory measurements and to understand when and why to use IR band strengths in a more appropriate manner. The history, interpretation, measurement, and common astrophysical applications of infrared band strengths will be discussed. The "secrets" of the laboratory techniques involved in their measurement are described, and a compilation of results from the literature is given along with some new results. Typical astrophysical applications and appropriate uses will also be discussed. Common misconceptions are confronted and two challenges are presented: (i) to the laboratory astrophysics community to produce and advertise accurate values with caveats when necessary, and (ii) to the observational community to use the most appropriate results for the environment under study.

  12. Spitzer mid-infrared spectroscopic observations of planetary nebulae

    NASA Astrophysics Data System (ADS)

    Mata, H.; Ramos-Larios, G.; Guerrero, M. A.; Nigoche-Netro, A.; Toalá, J. A.; Fang, X.; Rubio, G.; Kemp, S. N.; Navarro, S. G.; Corral, L. J.

    2016-06-01

    We present Spitzer Space Telescope archival mid-infrared (mid-IR) spectroscopy of a sample of 11 planetary nebulae (PNe). The observations, acquired with the Spitzer Infrared Spectrograph (IRS), cover the spectral range 5.2-14.5 μm that includes the H2 0-0 S(2) to S(7) rotational emission lines. This wavelength coverage has allowed us to derive the Boltzmann distribution and calculate the H2 rotational excitation temperature (Tex). The derived excitation temperatures have consistent values ≃900 ± 70 K for different sources despite their different structural components. We also report the detection of mid-IR ionic lines of [Ar III], [S IV], and [Ne II] in most objects, and polycyclic aromatic hydrocarbon features in a few cases. The decline of the [Ar III]/[Ne II] line ratio with the stellar effective temperature can be explained either by a true neon enrichment or by high density circumstellar regions of PNe that presumably descend from higher mass progenitor stars.

  13. Distributed Software for Observations in the Near Infrared

    NASA Astrophysics Data System (ADS)

    Gavryusev, V.; Baffa, C.; Giani, E.

    We have developed an integrated system that performs astronomical observations in Near Infrared bands operating two-dimensional instruments at the Italian National Infrared Facility's \\htmllink{ARNICA}{http://helios.arcetri.astro.it:/home/idefix/Mosaic/ instr/arnica/arnica.html} and \\htmllink{LONGSP}{http://helios.arcetri.astro.it:/home/idefix/Mosaic/ instr/longsp/longsp.html}. This software consists of several communicating processes, generally executed across a network, as well as on a single computer. The user interface is organized as widget-based X11 client. The interprocess communication is provided by sockets and uses TCP/IP. The processes denoted for control of hardware (telescope and other instruments) should be executed currently on a PC dedicated for this task under DESQview/X, while all other components (user interface, tools for the data analysis, etc.) can also work under UNIX\\@. The hardware independent part of software is based on the Athena Widget Set and is compiled by GNU C to provide maximum portability.

  14. Truncated stellar disks in the near infrared. I. Observations

    NASA Astrophysics Data System (ADS)

    Florido, E.; Battaner, E.; Guijarro, A.; Garzón, F.; Castillo-Morales, A.

    2006-08-01

    We present NIR surface photometry of 11 edge-on galaxies obtained in the course of a long term project aimed at analysing the occurrence and type of the truncation of the outer disks. Observations were carried out at the 1.5 m CST (Carlos Sánchez Telescope) in Tenerife (Spain) using the CAIN infrared camera. 7 galaxies exhibit clear truncation on their disk profiles and 4 galaxies were observed to be clearly untruncated within observational limits. We describe the truncations as real, smooth and complete (as suggested by extrapolation and in the sense that the measured truncation curve goes into the noise at a truncation radius R_tr), following a decline proportional to (R_tr -R)-n (where R is the radius). Despite its deep photometric reach, the data presented do not permit a detailed exploration of the region where optical data show a second slope. Special care was taken concerning the surface brightness deprojection of edge-on galaxies, which was carried out by two methods, one comprising the inversion of Abel's integral equation and the other following a numerical method. These methods gave nearly identical results. NIR observations of truncations could differ from observations in the optical, since the two domains trace different stellar populations.

  15. Bias in Hotelling observer performance computed from finite data

    NASA Astrophysics Data System (ADS)

    Kupinski, Matthew A.; Clarkson, Eric; Hesterman, Jacob Y.

    2007-03-01

    An observer performing a detection task analyzes an image and produces a single number, a test statistic, for that image. This test statistic represents the observers "confidence" that a signal (e.g., a tumor) is present. The linear observer that maximizes the test-statistic SNR is known as the Hotelling observer. Generally, computation of the Hotelling SNR, or Hotelling trace, requires the inverse of a large covariance matrix. Recent developments have resulted in methods for the estimation and inversion of these large covariance matrices with relatively small numbers of images. The estimation and inversion of these matrices is made possible by a covariance matrix decomposition that splits the full covariance matrix into an average detector-noise component and a background-variability component. Because the average detector-noise component is often diagonal and/or easily estimated, a full-rank, invertible covariance matrix can be produced with few images. We have studied the bias of estimates of the Hotelling trace using this decomposition for high-detector-noise and low-detector noise situations. In extremely low-noise situations, this covariance decomposition may result in a significant bias. We will present a theoretical evaluation of the Hotelling-trace bias, as well as extensive simulation studies.

  16. Observation of collisionally transferred spikes in 13CH3F by infrared-infrared double resonance

    NASA Astrophysics Data System (ADS)

    Matsuo, Yukari; Schwendeman, R. H.

    1989-10-01

    The method of infrared-infrared double resonance has been used to record the line shapes of a number of transitions in the 2ν3←ν3 band of 13CH3F by means of an infrared microwave sideband laser spectrometer while the QR(4,3) transition in the ν3 band was being pumped by constant-frequency radiation from a CO2 laser operating on the 9P(32) transition. A double modulation technique was used to eliminate single-resonance effects. The double-resonance line shapes for a series of transitions whose lower state is the (J,3) level in the v3=1 vibrational state show a transferred spike whose width is narrow for J values near 5, but slowly increases as J increases. The transferred spike is superimposed on a component of the line shape that is Gaussian with the expected Doppler width. Evidence for a transferred spike still remains for J=22. By contrast, for K≠3, there is only a Gaussian component for any J, except for J≊5, K=6, for which some evidence for a transferred spike can be seen. If the dominant selection rule for collisionally induced transitions is ΔJ=0,±1, then observation of a transferred spike for J=22 indicates some retention of velocity after as many as 17 collisions. The transferred spikes have been analyzed by a line shape function based on the Keilson-Storer collision kernel and the results have been used to estimate the root-mean-square value of the change in velocity upon collision.

  17. Observation of finite-. beta. MHD phenomena in tokamaks

    SciTech Connect

    McGuire, K.M.

    1984-09-01

    Stable high-beta plasmas are required for the tokamak to attain an economical fusion reactor. Recently, intense neutral beam heating experiments in tokamaks have shown new effects on plasma stability and confinement associated with high beta plasmas. The observed spectrum of MHD fluctuations at high beta is clearly dominated by the n = 1 mode when the q = 1 surface is in the plasma. The m/n = 1/1 mode drives other n = 1 modes through toroidal coupling and n > 1 modes through nonlinear coupling. On PDX, with near perpendicular injection, a resonant interaction between the n = 1 internal kink and the trapped fast ions results in loss of beam particles and heating power. Key parameters in the theory are the value of q/sub 0/ and the injection angle. High frequency broadband magnetic fluctuations have been observed on ISX-B and D-III and a correlation with the deterioration of plasma confinement was reported. During enhanced confinement (H-mode) discharges in divertor plasmas, two new edge instabilities were observed, both localized radially near the separatrix. By assembling results from the different tokamak experiments, it is found that the simple theoretical ideal MHD beta limit has not been exceeded. Whether this represents an ultimate tokamak limit or if beta optimized configurations (Dee- or bean-shaped plasmas) can exceed this limit and perhaps enter a second regime of stability remains to be clarified.

  18. 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.

  19. Infrared observations of the Jovian system from Voyager 1

    NASA Technical Reports Server (NTRS)

    Hanel, R.; Conrath, B.; Flasar, M.; Kunde, V.; Lowman, P.; Maguire, W.; Gautier, D.; Gierasch, P.; Kumar, S.; Ponnamperuma, C.

    1979-01-01

    The infrared spectroscopy and radiometry investigation has obtained spectra of Jupiter and its satellites between approximately 180 and 2500 kayser with a spectral resolution of 4.3 kayser. The Jupiter spectra show clear evidence of H2, CH4, C2H2, C2H6, CH3D, NH3, PH3, H2O, and GeH4. A helium concentration of 0.11 plus or minus 0.03 by volume is obtained. Meridional temperature cross sections show considerable structure. At high latitudes, the stratosphere is warmer in the north than in the south. The upper troposphere and lower stratosphere are locally cold over the Great Red Spot. Amalthea is warmer than expected. Considerable thermal structure is observed on Io, including a relatively hot region in the vicinity of a volcanic feature.

  20. Infrared observations of the jovian system from voyager 1.

    PubMed

    Hanel, R; Conrath, B; Flasar, M; Kunde, V; Lowman, P; Maguire, W; Pearl, J; Pirraglia, J; Samuelson, R; Gautier, D; Gierasch, P; Kumar, S; Ponnamperuma, C

    1979-06-01

    The infrared spectroscopy and radiometry investigation has obtained spectra of Jupiter and its satellites between approximately 180 and 2500 cm(-1) with a spectral resolution of 4.3 cm(-1). The Jupiter spectra show clear evidence of H(2), CH(4) C(2)H(2), C(2)H(6), CH(3)D, NH(3), PH(3), H(2)O, and GeH(4). A helium concentration of 0.11 +/- 0.03 by volume is obtained. Meridional temperature cross sections show considerable structure. At high latitudes, the stratosphere is warmer in the north than in the south. The upper troposphere and lower stratosphere are locally cold over the Great Red Spot. Amalthea is warmer than expected. Considerable thermal structure is observed on Io, including a relatively hot region in the vicinity of a volcanic feature.

  1. Infrared observations of the mechanical performance of tennis strings

    NASA Astrophysics Data System (ADS)

    Luong, Minh Phong

    2001-03-01

    The paper aims to illustrate three advantages of infrared thermography as a non-destructive, non-contact and real time technique (a) to detect the occurrence of intrinsic dissipation localization, (b) to observe the progressive damage processes and mechanisms of tennis string failure, and (c) to determine the optimal tension for each type of string. Experimental results evidence a limit of acceptable damage beyond which strings will fail due to the coalescence of defects and/or weakness zones. In addition, owing to the thermomechanical coupling, this technique provides a simple means for evaluating the wear resistance of strings of interest for skilled tennis players who impart on the ball a great amount of spin combined with a high stroke velocity.

  2. THERMAL INFRARED MMTAO OBSERVATIONS OF THE HR 8799 PLANETARY SYSTEM

    SciTech Connect

    Hinz, Philip M.; Rodigas, Timothy J.; Kenworthy, Matthew A.; Sivanandam, Suresh; Meyer, Michael R.; Heinze, Aren N.; Mamajek, Eric E.

    2010-06-10

    We present direct imaging observations at wavelengths of 3.3, 3.8 (L' band), and 4.8 (M band) {mu}m, for the planetary system surrounding HR 8799. All three planets are detected at L' . The c and d components are detected at 3.3 {mu}m, and upper limits are derived from the M-band observations. These observations provide useful constraints on warm giant planet atmospheres. We discuss the current age constraints on the HR 8799 system and show that several potential co-eval objects can be excluded from being co-moving with the star. Comparison of the photometry is made to models for giant planet atmospheres. Models that include non-equilibrium chemistry provide a reasonable match to the colors of c and d. From the observed colors in the thermal infrared, we estimate T {sub eff} < 960 K for b and T {sub eff} = 1300 and 1170 K for c and d, respectively. This provides an independent check on the effective temperatures and thus masses of the objects from the Marois et al. results.

  3. RECONCILING THE INFRARED CATASTROPHE AND OBSERVATIONS OF SN 2011fe

    SciTech Connect

    Fransson, Claes; Jerkstrand, Anders

    2015-11-20

    The observational effects of the “Infrared Catastrophe” are discussed in view of the very late observations of the Type Ia SN 2011fe. Our model spectra at 1000 days take non-local radiative transfer into account and find that this has a crucial impact on the spectral formation. Although rapid cooling of the ejecta to a few 100 K occurs also in these models, the late-time optical/NIR flux is brighter by 1–2 mag due to redistribution of UV emissivity, resulting from non-thermal excitation and ionization. This effect brings models into better agreement with late-time observations of SN 2011fe, and other SNe Ia, and offers a solution to the long-standing discrepancy between models and observations. The models show that spectral formation shifts from Fe ii and Fe iii at 300 days to Fe i at 1000 days, which explains the apparent wavelength shifts seen in SN 2011fe. We discuss the effects of time dependence and energy input from {sup 57}Co, finding both to be important at 1000 days.

  4. Keck Near-Infrared AO Observation of Io in 2011

    NASA Astrophysics Data System (ADS)

    Cantrall, C.; De Pater, I.; Nelson, D. M.; Williams, D. A.; de Kleer, K.

    2015-12-01

    We report observation and analysis of 23 distinct hot spots on Io from images taken in November of 2011 on the 10-m W.M. Keck II telescope. The observations were obtained with 8 different near-infrared (1-5 μm) filters, although no hot spots were detected at the smallest wavelength filters of Hc (1.58 μm) and Kc (2.27 μm). The radiant flux of each hot spot at the different wavelengths was found, which allowed for 1-T and 2-T blackbody fits to obtain estimates of the temperature, emission area, and subsequently, the total radiant output. Global maps over a cylindrical coordinate system were also constructed at each wavelength. In general, Io appeared to be fairly quiescent compared to datasets obtained between 2001 and 2010, with no significant outburst at any particular hot spot. Using GIS software it was possible to create surface maps that display the changes in some of the major hot spots observed between 2001 and 2011. The analysis of these maps and comparison to observations at different time periods will help to further construct a timeline of Io's volcanic activity, which will lead to a better understanding of the variations in surface heat flow over time, the global distribution of hot spots, and the style of eruptions.

  5. Discontinuous Observers Design for Finite-Time Consensus of Multiagent Systems With External Disturbances.

    PubMed

    Liu, Xiaoyang; Ho, Daniel W C; Cao, Jinde; Xu, Wenying

    2016-08-24

    This brief investigates the problem of finite-time robust consensus (FTRC) for second-order nonlinear multiagent systems with external disturbances. Based on the global finite-time stability theory of discontinuous homogeneous systems, a novel finite-time convergent discontinuous disturbed observer (DDO) is proposed for the leader-following multiagent systems. The states of the designed DDO are then used to design the control inputs to achieve the FTRC of nonlinear multiagent systems in the presence of bounded disturbances. The simulation results are provided to validate the effectiveness of these theoretical results.

  6. Gemini near-infrared observations of Europa's Hydrated Surface Materials

    NASA Astrophysics Data System (ADS)

    Tsang, C.; Spencer, J. R.; Grundy, W. M.; Dalton, J. B.

    2012-12-01

    Europa is a highly dynamic icy moon of Jupiter. It is thought the moon harbors a subsurface ocean, with the potential to sustain life, with Europa being a key target of ESA's forthcoming Jupiter Icy Moons Orbiter (JUICE) mission. However, much is not known concerning the chemistry of the subsurface ocean. The surface is dominated by water ice, with a hydrated non-ice material component providing the distinctive albedo contrasts seen at visible and near-infrared wavelengths. These non-ice materials are concentrated at disrupted surface regions, providing a diagnostic probe for the chemistry and characteristics of the liquid ocean beneath. Leading but potentially competing theories on the composition of these hydrated non-ice materials suggest either sulfuric acid-water mixtures (Carlson et al., 1999) or hydrated magnesium/sodium salts (McCord et al., 1999). Recent reanalysis of Galileo-NIMS observations suggest a mixture of both - hydrated salts are present at all longitudes but the sulfuric acid hydrates are localized on the trailing side. We present preliminary analysis of new ground-based Gemini disk-resolved spectroscopy of Europa using the Near-Infrared Integrated Field Spectrometer (NIFS), taken in late 2011, at H (1.49 - 1.80 μm) and K bands (1.99 - 2.40 μm) with spectral resolving powers of ~ 5300. At these NIR wavelengths, with spectral resolution much better than Galileo-NIMS, the spectral absorption and continuum characteristics of these ice and non-ice materials can be separated out. In addition, the spatial resolution potentially allows identification of localized materials whose signature would be diluted in disk-integrated spectra. These observations of the trailing hemisphere use Altair adaptive optics to achieve spatial resolutions of 0.1" (~310 km per pixel) or better, potentially leading to better identification of the non-ice materials and their spatial distributions. References Carlson, R.W., R.E. Johnson, and M.S. Anderson 1999. Sulfuric acid

  7. Some observations of separated flow on finite wings

    NASA Technical Reports Server (NTRS)

    Winkelmann, A. E.; Ngo, H. T.; De Seife, R. C.

    1982-01-01

    Wind tunnel test results for aspects of flow over airfoils exhibiting single and multiple trailing edge stall 'mushroom' cells are reported. Rectangular wings with aspect ratios of 4.0 and 9.0 were tested at Reynolds numbers of 480,000 and 257,000, respectively. Surface flow patterns were visualized by means of a fluorescent oil flow technique, separated flow was observed with a tuft wand and a water probe, spanwise flow was studied with hot-wire anemometry, smoke flow and an Ar laser illuminated the centerplane flow, and photographs were made of the oil flow patterns. Swirl patterns on partially and fully stalled wings suggested vortex flow attachments in those regions, and a saddle point on the fully stalled AR=4.0 wing indicated a secondary vortex flow at the forward region of the separation bubble. The separation wake decayed downstream, while the tip vortex interacted with the separation bubble on the fully stalled wing. Three mushroom cells were observed on the AR=9.0 wing.

  8. Faculae at the poles of the Sun revisited: infrared observations

    NASA Astrophysics Data System (ADS)

    Blanco Rodríguez, J.; Kneer, F.

    2010-01-01

    Aims: This study extends earlier investigations on faculae and their small-scale magnetic fields near the solar poles (polar faculae - PFe) to measurements of the magnetically sensitive infrared (IR) Fe I lines at 1.5 μm, which provide more accurate information about the magnetic field than lines in the visible spectral range. Methods: PFe were observed with the Tenerife Infrared Polarimeter (TIP II) mounted at the Vacuum Tower Telescope/Observatorio del Teide/Tenerife. Several areas at various heliocentric angles were scanned. Faculae near the solar equator (equatorial faculae - EFe) were also observed for comparison with PFe. The full Stokes vector of the Fe I line pair at 1.5 μm was measured. The magnetic field properties were determined (1) from the centre of gravity (COG); (2) with the weak field approximation (WFA); (3) assuming the strong field regime (SFR); and (4) with inversions under the hypothesis of Milne-Eddington (ME) atmospheres. Line-of-sight (LOS) velocities were determined from the COG of I profiles and from the zero-crossing of the V profiles. Results: The main findings of this work can be divided in five parts: (1) the detected PFe do not harbour sufficient magnetic flux to account for the global flux observed with other methods. (2) Near the solar limb, the apparent, measured transversal field components are most times stronger than the longitudinal components by factors of up to 10 for both PFe and EFe, as found from observations with HINODE SOT. (3) Many PFe indeed harbour kilo-G magnetic fields. Of those, more than 85% possess the same magnetic polarity as the global field. The inclinations γ of the strong fields, \\vert B\\vert≥ 900 G in the SFR, are compatible with their vertical emergence from the solar surface. (4) The results for weaker fields, \\vert B\\vert≤ 600 G from ME inversions, indicate a random magnetic field orientation. (5) The velocities from I profiles and V zero-crossings are in average 0.3 km s-1 towards observer

  9. Exploration of the Saturn System by the Cassini Mission: Observations with the Cassini Infrared Spectrometer

    NASA Technical Reports Server (NTRS)

    Abbas, Mian M.

    2014-01-01

    Outline: Introduction to the Cassini mission, and Cassini mission Objectives; Cassini spacecraft, instruments, launch, and orbit insertion; Saturn, Rings, and Satellite, Titan; Composite Infrared Spectrometer (CIRS); and Infrared observations of Saturn and titan.

  10. Ground-based Infrared Observations of Water Vapor and Hydrogen Peroxide in the Atmosphere of Mars

    NASA Astrophysics Data System (ADS)

    Encrenaz, T.; Greathouse, T. K.; Bitner, M.; Kruger, A.; Richter, M. J.; Lacy, J. H.; Bézard, B.; Fouchet, T.; Lefevre, F.; Forget, F.; Atreya, S. K.

    2008-11-01

    Ground-based observations of water vapor and hydrogen peroxide have been obtained in the thermal infrared range, using the TEXES instrument at the NASA Infrared Telescope Facility, for different times of the seasonal cycle.

  11. Surface boiling - an "obvious" explanation for the observed limiting temperature of finite nuclei

    NASA Astrophysics Data System (ADS)

    Tõke, J.

    2012-07-01

    Limits of stability of nuclear systems are explored within the framework of a finite-range interacting Fermi gas model and microcanonical thermodynamics in Thomas-Fermi approximation. It is found that with increasing excitation energy, infinite systems become unstable against volume boiling, while finite systems become subject to surface boiling, providing a natural explanation for the observed saturationlike patterns, or limiting temperature, in caloric curves. Boiling patterns of iso-asymmetric matter are discussed.

  12. An Airborne Infrared Telescope and Spectrograph for Solar Eclipse Observations

    NASA Astrophysics Data System (ADS)

    DeLuca, Edward E.; Cheimets, Peter; Golub, Leon

    2014-06-01

    The solar infrared spectrum offers great possibilities for direct spatially resolved measurements of the solar coronal magnetic fields, via imaging of the plasma that is constrained to follow the magnetic field direction and via spectro-polarimetry that permits measurement of the field strength in the corona. Energy stored in coronal magnetic fields is released in flares and coronal mass ejections (CME) and provides the ultimate source of energy for space weather. The large scale structure of the coronal field, and the opening up of the field in a transition zone between the closed and open corona determines the speed and structure of the solar wind, providing the background environment through which CMEs propagate. At present our only direct measurements of the solar magnetic fields are in the photosphere and chromosphere. The ability to determine where and why the corona transitions from closed to open, combined with measurements of the field strength via infrared coronal spectro-polarimetry will give us a powerful new tool in our quest to develop the next generation of forecasting models.We describe a first step in achieving this goal: a proposal for a new IR telescope, image stabilization system, and spectrometer, for the NCAR HIPER GV aircraft. The telescope/spectrograph will operate in the 2-6micron wavelength region, during solar eclipses, starting with the trans-north American eclipse in August 2017. The HIAPER aircraft flying at ~35,000 ft will provide an excellent platform for IR observations. Our imaging and spectroscopy experiment will show the distribution and intensity of IR forbidden lines in the solar corona.

  13. Mid-Infrared Observation of Mass Loss in Elliptical Galaxies

    NASA Astrophysics Data System (ADS)

    Athey, Alex; Bregman, Joel; Bregman, Jesse; Temi, Pasquale; Sauvage, Marc

    2002-05-01

    Early-type galaxies exhibit thermal and molecular resonance emission from dust that is shed and heated through stellar mass loss as a subset of the population moves through the asymptotic giant branch (AGB) phase of evolution. Because this emission can give direct insight into stellar evolution in addition to galactic stellar mass loss and interstellar medium injection rates, we conducted a program to search for this signature emission with CAM on the Infrared Space Observatory. We obtained 6-15 μm imaging observations in six narrow bands for nine elliptical galaxies; every galaxy is detected in every band. For wavelengths shorter than 9 μm, the spectra are well matched by a blackbody originating from the K and M stars that dominate the integrated light of elliptical galaxies. At wavelengths between 9 and 15 μm, however, the galaxies display excess emission relative to the stellar photospheric radiation. Additional data taken with the fine-resolution circular variable filter on one source clearly shows broad emission from 9 to 15 μm, peaking around 10 μm. This result is consistent with the known broad silicate feature at 9.7 μm originating in the circumstellar envelopes of AGB stars. This emission is compared with studies of Galactic and Large Magellanic Cloud AGB stars to derive cumulative mass-loss rates. In general, these mass-loss rates agree with the expected ~0.8 Msolar yr-1 value predicted by stellar evolutionary models. Both the photospheric and circumstellar envelope emission follow a de Vaucouleurs R1/4 law, supporting the conclusion that the mid-infrared excess emission originates in the stellar component of the galaxies and acts as a tracer of AGB mass loss and mass injection into the interstellar medium.

  14. 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.

  15. The VIRMOS deep imaging survey. IV. Near-infrared observations

    NASA Astrophysics Data System (ADS)

    Iovino, A.; McCracken, H. J.; Garilli, B.; Foucaud, S.; Le Fèvre, O.; Maccagni, D.; Saracco, P.; Bardelli, S.; Busarello, G.; Scodeggio, M.; Zanichelli, A.; Paioro, L.; Bottini, D.; Le Brun, V.; Picat, J. P.; Scaramella, R.; Tresse, L.; Vettolani, G.; Adami, C.; Arnaboldi, M.; Arnouts, S.; Bolzonella, M.; Cappi, A.; Charlot, S.; Ciliegi, P.; Contini, T.; Franzetti, P.; Gavignaud, I.; Guzzo, L.; Ilbert, O.; Marano, B.; Marinoni, C.; Mazure, A.; Meneux, B.; Merighi, R.; Paltani, S.; Pellò, R.; Pollo, A.; Pozzetti, L.; Radovich, M.; Zamorani, G.; Zucca, E.; Bertin, E.; Bondi, M.; Bongiorno, A.; Cucciati, O.; Gregorini, L.; Mathez, G.; Mellier, Y.; Merluzzi, P.; Ripepi, V.; Rizzo, D.

    2005-11-01

    In this paper we present a new deep, wide-field near-infrared imaging survey. Our J- and K-band observations in four separate fields (0226-04, 2217+00, 1003+02, 1400+05) complement optical BVRI, ultraviolet and spectroscopic observations undertaken as part of the VIMOS-VLT deep survey (VVDS). In total, our survey spans ~400 arcmin2. Our catalogues are reliable in all fields to at least K˜20.75 and J˜21.50 (defined as the magnitude where object contamination is less than 10% and completeness greater than 90%). Taken together these four fields represents a unique combination of depth, wavelength coverage and area. Most importantly, our survey regions span a broad range of right ascension and declination which allow us to make a robust estimate of the effects of cosmic variance. We describe the complete data reduction process from raw observations to the construction of source lists and outline a comprehensive series of tests carried out to characterise the reliability of the final catalogues. From simulations we determine the completeness function of each final stacked image, and estimate the fraction of spurious sources in each magnitude bin. We compare the statistical properties of our catalogues with literature compilations. We find that our J- and K-selected galaxy counts are in good agreement with previously published works, as are our (J-K) versus K colour-magnitude diagrams. Stellar number counts extracted from our fields are consistent with a synthetic model of our galaxy. Using the location of the stellar locus in colour-magnitude space and the measured field-to-field variation in galaxy number counts we demonstrate that the absolute accuracy of our photometric calibration is at the 5% level or better. Finally, an investigation of the angular clustering of K-selected extended sources in our survey displays the expected scaling behaviour with limiting magnitude, with amplitudes in each magnitude bin in broad agreement with literature values. In summary

  16. Near infrared observations of the truncation of stellar disks

    NASA Astrophysics Data System (ADS)

    Florido, E.; Battaner, E.; Guijarro, A.; Garzón, F.; Jiménez-Vicente, J.

    2001-10-01

    We present a first study of truncation of the stellar disks of spiral galaxies in the near infrared. Observations of NGC 4013, NGC 4217, NGC 6504 and NGC 5981 were made with the CAIN NIR camera on the CST in Tenerife. This wavelength range provides the best description of the phenomenon, not only because extinction effects are minimized, but also because the distribution of the old stellar population is directly obtained. The four galaxies are edge-on and an inversion method was developed to obtain the deprojected profiles. We did not assume any model of the different galactic components. The ``truncation curve'', i.e. T(R) = mu (R)- mu D(R), where mu is the actual surface brightness in mag/arcsec2 and mu D the exponential disk surface brightness, has been obtained with unprecedented precision. It is suggested that T(R) is proportional to (Rt-R)-1, where Rt is the truncation radius, i.e. the radius beyond which no star is observed.

  17. Infrared Observations of Star-Forming Dwarf Galaxies with Spitzer

    NASA Astrophysics Data System (ADS)

    Rosenberg, J. L.; Ashby, M. L. N.; Salzer, J. J.

    2004-12-01

    We present a study of the infrared properties of a sample of actively star-forming dwarf galaxies (MB >-18) drawn from the KPNO International Spectroscopic Survey. Nearby actively star-forming dwarf galaxies are possible analogs to the high redshift star-forming systems that serve as galactic building blocks in hierarchical galaxy formation scenarios. These galaxies are gas-rich, metal-poor systems undergoing bursts of star formation in the local universe. A subset of such objects from the line-flux limited objective-prism survey of Salzer et al. (2001) lie in the NOAO Bootes field, and have therefore been observed by Spitzer as part of the IRAC Shallow Survey. We use the IRAC data to measure the stellar mass in these galaxies. In addition, we examine whether these metal-poor dwarf galaxies show warm dust emission, and examine whether it traces the star formation as it does in normal disk galaxies. J. L. Rosenberg would like to acknowledge the NSF Astronomy and Astrophysics Fellowship for support of this work. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. Support for this work was provided by NASA.

  18. Mid infrared observations of Van Maanen 2: no substellar companion.

    SciTech Connect

    Farihi, J; Becklin, E; Macintosh, B

    2004-11-03

    The results of a comprehensive infrared imaging search for the putative 0.06 M{sub {circle_dot}} astrometric companion to the 4.4 pc white dwarf van Mannen 2 are reported. Adaptive optics images acquired at 3.8 {micro}m reveal a diffraction limited core of 0.09 inch and no direct evidence of a secondary. Models predict that at 5 Gyr, a 50 M{sub J} brown dwarf would be only 1 magnitude fainter than van Maanen 2 at this wavelength and the astrometric analysis suggested a separation of 0.2 inch. In the case of a chance alignment along the line of sight, a 0.4 mag excess should be measured. An independent photometric observation at the same wavelength reveals no excess. In addition, there exist published ISO observations of van Maanen 2 at 6.8 {micro}m and 15.0 {micro}m which are consistent with photospheric flux of a 6750 K white dwarf. If recent brown dwarf models are correct, there is no substellar companion with T{sub eff} {approx}> 500 K.

  19. Observations of tropospheric trace gases from GOSAT thermal infrared spectra

    NASA Astrophysics Data System (ADS)

    Ohyama, Hirofumi; Shiomi, Kei; Kawakami, Shuji; Nakajima, Masakatsu; Maki, Takashi; Deushi, Makoto

    2013-04-01

    Thermal And Near infrared Sensor for carbon Observation-Fourier Transform Spectrometer (TANSO-FTS), which is one of the sensors onboard the Greenhouse gases Observing SATellite (GOSAT), measures the sunlight backscattered by the Earth's surface and atmosphere as well as the thermal radiance emitted from the Earth. Atmospheric trace gases such as ozone (O3), water vapor (H2O and HDO), methanol (CH3OH) and ammonia (NH3) are derived from the thermal infrared spectral radiance recorded with the TANSO-FTS by an optimal estimation retrieval approach. TANSO-FTS total ozone columns are compared with Dobson spectrophotometer and Ozone Monitoring Instrument (OMI) data. The TANSO-FTS total ozone retrievals exhibit a positive bias of 3-4% with a root-mean-square difference of 2-6% compared to the Dobson and OMI measurements. We compare TANSO-FTS tropospheric ozone columns to those from ozonesonde data as well as from a three-dimensional chemical-climate model (MRI-CCM2). The TANSO-FTS data have high correlations with the ozonesonde data. The seasonal trends of the retrieved tropospheric ozone are consistent with those of the ozonesonde data. The spatial distribution of the tropospheric ozone from the TANSO-FTS and MRI-CCM2 shows good agreement, especially in the high-level tropospheric ozone regions. We also retrieve tropospheric H2O and HDO profiles simultaneously, accounting for the cross correlations between the water isotopes. The joint retrieval results in precise estimation of the isotope ratio by partial cancellation of systematic errors common to both H2O and HDO. The retrieved profiles and columns are compared with radiosonde, GPS, and ground-based high-resolution FTS data. The temporal and spatial variations of the precipitable water and the isotope ratio are consistent with those of the validation data. Finally, air pollutants such as CH3OH and NH3 are retrieved using the retrieved ozone and water vapor. We present the latitudinal and seasonal variations of CH3OH

  20. Cirrus Infrared Parameters and Shortwave Reflectance Relations from Observations.

    NASA Astrophysics Data System (ADS)

    Spinhirne, James D.; Hart, William D.; Hlavka, Dennis L.

    1996-05-01

    A summary of experimental observations and analysis of cirrus from high-altitude aircraft remote sensing is presented. The vertical distribution of cirrus optical and infrared cross-section parameters and the relative effective emittance and visible reflectance are derived from nadir-viewing lidar and multispectral radiometer data for observations during the 1986 and 1991 FIRE cirrus experiments. Statistics on scattering and absorption cross sections in relation to altitude and temperature are given. The emittance and reflectance results are considered as a function of solar zenith angle. Comparative radiative transfer calculations based on the discrete-ordinate method were carried out for three representative cloud phase function models: a spherical water droplet, an ice column crystal cloud, and a Henyey-Greenstein function. The agreements between observations of the effective emittance and shortwave reflectance and the model calculations were a function of the solar zenith angle. At angles between 54° and 60° a Henyey-Greenstein (HG) function with an asymmetry factor of 0.6-0.7 produced the best comparison. At 66°-72° the ice column model was equally comparable to observations. Comparisons to the water cloud model wore poor in all cases. The effects of ice crystal microphysical variations on the observed results were not generally apparent, but one dramatic example of difference was found. In order to explain the variations noted for solar zenith angle, an instrument-the Tilt Scan CCD Camera radiometer-was developed to directly observe the shortwave bidirectional reflectance function for 1991 measurements. The results indicate a characteristic angular function of the visible reflectance of cirrus that is flatter than predicted by the ice column scattering model, but the overall asymmetry factor is comparable. The good agreement with values from an HG function at some angles is not generally applicable. The characteristics of the observed cirrus angular

  1. AIRS Infrared Radiance Validation Concept Using Earth Scene Observations

    NASA Astrophysics Data System (ADS)

    Hagan, D. E.; Aumann, H. H.; Pagano, T. S.; Strow, L. L.

    2001-05-01

    The Atmospheric Infrared Sounder (AIRS) will fly onboard the NASA Earth Observing Satellite (EOS)polar-orbiting Aqua spacecraft. AIRS, a high resolution infrared spectrometer with visible and near-infrared spectral channels, has been designed to provide atmospheric temperature and moisture profiles at least as accurate as those measured by standard radiosondes. Calibration studies of the response of each of the AIRS 4000+ detectors will begin as soon as the spacecraft orbit and instrument have stabilized. These studies are needed to help assess the contribution of instrument measurement errors to the spectral radiance determination. Some of the uncertainties will be determined from measurements of the onboard calibrators. Other sources of measurement uncertainty, such as scan mirror polarization and spectral response functions, require views of Earth at nadir and at oblique viewing angles, in cloud-free conditions. During early operation of the instrument, the blackbody radiance determination will rely on pre-launch measurements and models of the spectral response functions. During this phase of the operation, we have chosen an approach for initial assessment of the accuracy of the measured radiance that is not dependent on an exact knowledge of the spectral position of the detectors. Radiances will be evaluated in narrow regions that are well removed from spectral line features. There are potentially hundreds of detectors that can be used for this purpose. Our work to date has focused on a subset of these detectors located in atmospheric window regions between 2500-2700 cm-1 and 800-1200 cm-1. Pre-launch thermal-vacuum blackbody calibration results indicate that, using a reasonable cross-section of detectors, it should be possible to extrapolate the performance of a sparse set of detectors to the general state of the instrument calibration. In this paper we describe some initial results using a simple statistical methodology that compares outgoing radiances in

  2. Mid-Infrared observations of NGC6946 with ISOCAM

    NASA Astrophysics Data System (ADS)

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

    1996-05-01

    We present 7 and 15 mu m images of NGC 6946 taken with the CAM instrument on ISO. This is the first CAM data from our ``US Key Project'' (Helou et al. 1996), which uses ISO LWS, CAM and PHOT observations to study ISM properties in normal galaxies. NGC 6946 is a nearby flocculent spiral galaxy with mostly normal star-formation pattern that peaks very strongly near the nucleus. The images were taken with a resolution of 6 arcsec , corresponding to 300 pc for an assumed distance to NGC 6946 of 10 Mpc. The emission at 7 mu m is believed to be dominated by PAHs (Polycyclic Aromatic Hydrocarbons), and the 15 mu m emission is primarily from the stochastically heated VSG (Very Small Grains) and very hot dust very near HII regions. The mid-infrared maps of NGC 6946 at both wavelengths clearly trace the spiral structure, and resolve structure therein. They will allow us to study in detail the spatial distribution of these emission components and their relation to spiral arms and HII regions. The ratio of 7 to 15 mu m maps will trace the relative strength of the two emission mechanisms, and may well yield a measure of the hardness of the heating spectrum in various parts of the galaxy.

  3. Near-Infrared Observations of Compact Binary Systems

    NASA Astrophysics Data System (ADS)

    Khargharia, Juthika

    Low mass X-ray binaries (LMXBs) are a subset of compact binary systems in which a main-sequence or slightly evolved star fills its Roche lobe and donates mass to a neutron star or a black hole (BH) via an accretion disk. Robust estimates of compact object masses in these systems are required to enhance our current understanding of the physics of compact object formation, accretion disks and jets. Compact object masses are typically determined at near-infrared (NIR) wavelengths when the system is in quiescence and the donor star is the dominant source of flux. Previous studies have assumed that any non-stellar contribution at these wavelengths is minimal. However, this assumption is rarely true. By performing NIR spectroscopy, we determined the fractional donor star contribution to the NIR flux and the compact object masses in two LMXBs: V404 Cyg and Cen X-4. In our analysis, it was assumed that the light curve morphology remains consistent throughout quiescence. It has now been shown in several systems that veiling measurements from non-stellar sources are meaningful only if acquired contemporaneously with light curve measurements. We accounted for this in the measurement of the BH mass in the LMXB, XTE J1118+480. LMXBs are also considered to be the most likely candidates responsible for the formation of milli-second pulsars (MSP). Here, I present the unique case of PSR J1903+0327 that challenges this currently accepted theory of MSP formation and is a potential candidate for testing General Relativity. Observations in the NIR come with their own set of challenges. NIR detector arrays used in these observations generally have high dark current and readout noise. In an effort to lower the read noise in NICFPS at APO, we present a study done on the Hawaii-1RG engineering grade chip that served as a test bed for reducing the read noise in NICFPS.

  4. HST/WFPC2 Observations of Warm Ultraluminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Surace, Jason A.; Sanders, D. B.; Vacca, William D.; Veilleux, Sylvain; Mazzarella, J. M.

    1998-01-01

    We present new high-resolution B- and I-band images of a nearly complete sample of nine ``warm'' (f25/f60 > 0.2), ultraluminous infrared galaxies (ULIGs) obtained with the Wide Field Planetary Camera of the Hubble Space Telescope (HST). The HST images clearly reveal the presence of tidal tails and other features associated with merging galaxies. All of the warm ULIGs show evidence of complex structures such as dust lanes and spiral features in their inner few kiloparsecs. Additionally, they show compact, blue ``knots'' of star formation (between 4 and 31 knots per object) that appear similar to those seen in more nearby merger systems. Spectral synthesis modeling is used to estimate mean upper age limits and masses: the median upper age limit for the knots in individual galaxies is ~3 × 108 yr (ranging from ~107 to 1 × 109 yr), and the range of knot masses is ~105-109 M⊙. We also argue that these starburst knots cannot be significant contributors to the extremely high bolometric luminosity of these galaxies. Additionally, each object contains one or two knots whose luminosity and color are implausible in terms of star formation; we identify these as putative active nuclei. These observations are consistent with the hypothesis that warm ULIGs may represent a critical transition stage in the evolution of ULIGs into optical quasi-stellar objects. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  5. Rocket-borne instrument for observations of near-infrared and far-infrared extended astrophysical emission

    NASA Technical Reports Server (NTRS)

    Matsuhara, Hideo; Kawada, Mitsunobu; Matsumoto, Toshio; Matsuura, Shuji; Tanaka, Masahiro; Bock, James J.; Hristov, Viktor V.; Lange, Andrew E.; Mauskopf, Philip D.; Richards, Paul L.

    1994-01-01

    We give a detailed description of the design and flight performance of an instrument onboard the S-520-15 rocket of the Institute of Space and Astronautical Science. The isntrument, consisting of a near-infrared spectrometer and a far-infrared photometer at the focus of a 10 cm liquid-helium cooled telescope, was designed to observe both the brightness and distribution of diffuse emission with high sensitivity. The rocket was successfully launched and the instrument observed near-infrared and far-infrared continuum emission, as well as (C II) 157.7 micrometer line emission from regions at high Galactic latitude. We also give a brief description of the design and performance of an onboard attitude control system.

  6. Infrared observations of the spiral galaxy NGC 891

    NASA Astrophysics Data System (ADS)

    Whaley, Cynthia

    2007-08-01

    This thesis is a detailed, multi-waveband study of the inner 14 kpc of the famous spiral galaxy, NCG 891. The primary data have come from the Infrared Space Observatory's Camera. These data are images of the galaxy in 9 different mid-infrared wavebands. We have supported these data with archived data from the Spitzer Infrared Array Camera in 4 similar wavebands. Surface brightness contour maps of the galaxy were created and examined to determine where the mid-infrared emitters are located with respect to the galactic plane. We have determined that the main mid-infrared emission, due to warm dust and PAHs, lies in a thin disk of width 700 - 800 pc, but has faint emission that reaches up to about 2.3 kpc into the halo. The infrared spectral energy distribution (SED) for four environments in NGC 891 were created from the above mentioned wavebands as well as measurements from Spitzer's Multiband Imaging Photometer (3 Far-Infrared wavebands), the Two Micron All Sky Survey J, H, and K near-infrared wavebands, and the Sub- millimeter Common User Bolometer Array 450 and 850 mm bands. These spectra were fit with a SED model created by Frederic Galliano, and the physical properties of these environments were computed. The maps and SED show that while there is a relatively large amount of dust in NGC 891's halo, there is a depletion of PAHs beyond 2.3 kpc from the mid-plane. This is only the fourth galaxy to date that has PAH emission discovered in the halo, and it is the first in which the SED has been modeled for the halo.

  7. Remote sensing of aerosols over snow using infrared AATSR observations

    NASA Astrophysics Data System (ADS)

    Istomina, L. G.; von Hoyningen-Huene, W.; Kokhanovsky, A. A.; Schultz, E.; Burrows, J. P.

    2011-06-01

    Infrared (IR) retrievals of aerosol optical thickness (AOT) are challenging because of the low reflectance of aerosol layer at longer wavelengths. In this paper we present a closer analysis of this problem, performed with radiative transfer (RT) simulations for coarse and accumulation mode of four main aerosol components. It shows the strong angular dependence of aerosol IR reflectance at low solar elevations resulting from the significant asymmetry of aerosol phase function at these wavelengths. This results in detectable values of aerosol IR reflectance at certain non-nadir observation angles providing the advantage of multiangle remote sensing instruments for a retrieval of AOT at longer wavelengths. Such retrievals can be of importance e.g. in case of a very strong effect of the surface on the top of atmosphere (TOA) reflectance in the visible spectral range. In the current work, a new method to retrieve AOT of the coarse and accumulation mode particles over snow has been developed using the measurements of Advanced Along Track Scanning Radiometer (AATSR) on board the ENVISAT satellite. The algorithm uses AATSR channel at 3.7 μm and utilizes its dual-viewing observation technique, implying the forward view with an observation zenith angle of around 55 degrees and the nadir view. It includes cloud/snow discrimination, extraction of the atmospheric reflectance out of measured brightness temperature (BT) at 3.7 μm, and interpolation of look-up tables (LUTs) for a given aerosol reflectance. The algorithm uses LUTs, separately simulated with RT forward calculations. The resulting AOT at 500 nm is estimated from the value at 3.7 μm using a fixed Angström parameter. The presented method has been validated against ground-based Aerosol Robotic Network (AERONET) data for 4 high Arctic stations and shows good agreement. A case study has been performed at W-Greenland on 5 July 2008. The day before was characterized by a noticeable dust event. The retrieved AOT maps of

  8. Infrared, radio, and X-ray observations of Cygnus X-3

    NASA Technical Reports Server (NTRS)

    Becklin, E. E.; Neugebauer, G.; Hawkins, F. J.; Mason, K. O.; Sanford, P. W.; Matthews, K.; Packman, D.; Schupler, B.; Stark, A.; Wynn-Williams, C. G.

    1974-01-01

    Infrared observations of Cyg X-3 are presented along with X-ray and radio data. A study of the data shows evidence for several types of behavior in the infrared flux variations of Cyg X-3. It is pointed out that a lack of periodic variations observed can be due either to a real absence of these variations or to a masking by an outburst preceding the observation time. There is no simple radio-infrared correlation, although both radio and infrared emissions were observed during the same period of time.

  9. Infrared observations of Comet Austin (1990 V) by the COBE/Diffuse Infrared Background Experiment

    NASA Technical Reports Server (NTRS)

    Lisse, C. M.; Freudenreich, H. T.; Hauser, M. G.; Kelsall, T.; Moseley, S. H.; Reach, W. T.; Silverberg, R. F.

    1994-01-01

    Comet Austin was observed by the Cosmic Background Explorer (COBE)/Diffuse Infrared Background Experiment (DIRBE) with broadband photometry at 1-240 micrometers during the comet's close passage by Earth in 1990 May. A 6 deg long (6 x 10(exp 6) km) dust tail was found at 12 and 25 micrometers, with detailed structure due to variations in particle properties and mass-loss rate. The spectrum of the central 42 x 42 sq arcmin pixel was found to agree with that of a graybody of temperature 309 +/- 5 K and optical depth 7.3 +/- 10(exp -8). Comparison with IUE and ground-based obervations indicates that particles of radius greater than 20 micrometers predominate by surface area. A mass-loss rate of 510 (+510/-205) kg/s and a total tail mass of 7 +/- 2 x 10(exp 10) kg was found for a model dust tail composed of Mie spheres with a differential particle mass distribution dn/d log m approx. m(exp -0.63) and 2:1 silicate:amorphous carbon composition by mass.

  10. LOCAL LUMINOUS INFRARED GALAXIES. I. SPATIALLY RESOLVED OBSERVATIONS WITH THE SPITZER INFRARED SPECTROGRAPH

    SciTech Connect

    Pereira-Santaella, Miguel; Alonso-Herrero, Almudena; Colina, Luis; Diaz-Santos, Tanio; Rieke, George H.; Engelbracht, Charles W.; Smith, J.-D. T.; Perez-Gonzalez, Pablo G.

    2010-06-15

    We present results from the Spitzer Infrared Spectrograph spectral mapping observations of 15 local luminous infrared galaxies (LIRGs). In this paper, we investigate the spatial variations of the mid-IR emission which includes fine structure lines, molecular hydrogen lines, polycyclic aromatic features (PAHs), continuum emission, and the 9.7 {mu}m silicate feature. We also compare the nuclear and integrated spectra. We find that the star formation takes place in extended regions (several kpc) as probed by the PAH emission, as well as the [Ne II]12.81 {mu}m and [Ne III]15.56 {mu}m emissions. The behavior of the integrated PAH emission and 9.7 {mu}m silicate feature is similar to that of local starburst galaxies. We also find that the minima of the [Ne III]15.56 {mu}m/[Ne II]12.81 {mu}m ratio tends to be located at the nuclei and its value is lower than that of H II regions in our LIRGs and nearby galaxies. It is likely that increased densities in the nuclei of LIRGs are responsible for the smaller nuclear [Ne III]15.56 {mu}m/[Ne II]12.81 {mu}m ratios. This includes the possibility that some of the most massive stars in the nuclei are still embedded in ultracompact H II regions. In a large fraction of our sample, the 11.3 {mu}m PAH emission appears more extended than the dust 5.5 {mu}m continuum emission. We find a dependency of the 11.3 {mu}m PAH/7.7 {mu}m PAH and [Ne II]12.81 {mu}m/11.3 {mu}m PAH ratios with the age of the stellar populations. Smaller and larger ratios, respectively, indicate recent star formation. The estimated warm (300 K

  11. A multiwavelength observation and investigation of six infrared dark clouds

    NASA Astrophysics Data System (ADS)

    Zhang, Chuan-Peng; Yuan, Jing-Hua; Li, Guang-Xing; Zhou, Jian-Jun; Wang, Jun-Jie

    2017-02-01

    Context. Infrared dark clouds (IRDCs) are ubiquitous in the Milky Way, yet they play a crucial role in breeding newly-formed stars. Aims: With the aim of further understanding the dynamics, chemistry, and evolution of IRDCs, we carried out multiwavelength observations on a small sample. Methods: We performed new observations with the IRAM 30 m and CSO 10.4 m telescopes, with tracers HCO+, HCN, N2H+, C18O, DCO+, SiO, and DCN toward six IRDCs G031.97+00.07, G033.69-00.01, G034.43+00.24, G035.39-00.33, G038.95-00.47, and G053.11+00.05. Results: We investigated 44 cores including 37 cores reported in previous work and seven newly-identified cores. Toward the dense cores, we detected 6 DCO+, and 5 DCN lines. Using pixel-by-pixel spectral energy distribution (SED) fits of the Herschel 70 to 500 μm, we obtained dust temperature and column density distributions of the IRDCs. We found that N2H+ emission has a strong correlation with the dust temperature and column density distributions, while C18O showed the weakest correlation. It is suggested that N2H+ is indeed a good tracer in very dense conditions, but C18O is an unreliable one, as it has a relatively low critical density and is vulnerable to freezing-out onto the surface of cold dust grains. The dynamics within IRDCs are active, with infall, outflow, and collapse; the spectra are abundant especially in deuterium species. Conclusions: We observe many blueshifted and redshifted profiles, respectively, with HCO+ and C18O toward the same core. This case can be well explained by model "envelope expansion with core collapse (EECC)". The final datacubes (HCO+, HCN, N2H+, C18O) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/598/A76

  12. Molecular line observations of infrared dark clouds in the galaxy

    NASA Astrophysics Data System (ADS)

    Finn, Susanna C.

    Although massive stars play many important roles in the universe, their formation is poorly understood. Recently, a class of interstellar clouds known as Infrared Dark Clouds (IRDCs) has been identified as likely progenitors of massive stars and clusters. These clouds are dense (nH 2 > 105 cm--3), cold (T < 20 K), have very high column densities (N ˜ 1023--10 25 cm--2), and contain dense clumps and cores. In this dissertation, I present radio observations of a large sample of IRDCs in order to examine their properties and explore the hypothesis that high-mass stars and clusters form in these dense, cold molecular clouds. I determine kinematic distances to a large sample of IRDCs in the inner Galaxy based on CS (2--1) radial velocities. IRDCs are concentrated at specific Galactocentric radii and their distribution appears to trace Milky Way spiral structure. To identify IRDC clumps and determine properties such as mass, size, and chemical evolution, I map a sample of IRDCs in various high density-tracing molecular transitions. The size and mass estimates show that IRDC clumps are comparable in size to more evolved regions of massive star formation. I compare the integrated intensities and linewidths of the molecular emission with a proposed evolutionary sequence of the clumps. The ratio of N2H + with HNC, HCN, and HCO+ is a function of evolutionary stage. The linewidths and virial parameters of the clumps show no clear trend with the evolutionary sequence. Finally, I explore the filamentary shape of IRDCs. The "sausage instability," which describes clumps forming in a gas cylinder, is explored as a mechanism for star-forming clumps to collapse in filaments. First, I compare observations of the "Nessie Nebula," an extreme case of a filamentary IRDC, with predictions from the theory of the fluid instability and then expand the sample to other filamentary IRDCs. The observations are consistent with theoretical predictions of clump spacing, clump masses, and linear

  13. ISO completes its observations of the Universe by infrared light

    NASA Astrophysics Data System (ADS)

    1998-04-01

    At 07:00 on 8 April 1998, engineers at ESA's ground station at Villafranca near Madrid reported that ISO's telescope was beginning to warm up, above its nominal operating temperature close to absolute zero. This was the sign that ISO had exhausted the superfluid helium used to achieve the very low temperatures necessary for infrared astronomy. Observations ceased at 23h07 when the temperature of the instruments had risen above -269°C. At that time, ISO was observing the galaxy NGC 1808 with the camera (ISOCAM) for Prof. J. Hough (UK). The astronomers then handed ISO over to the engineering team for check-outs and decommissioning. The spacecraft will be switched off in about 28 days' time. Infrared rays come from cool places in the sky, and ISO would have been dazzled by its own heat unless its optical system were extremely cold. At its launch in November 1995, ISO carried a supply of 2000 litres of superfluid helium, which boils at -271 degrees C. Slow venting of the helium into space maintained the low temperature of the optical system. How did ISO achieve its extended life? Three months came from a prudent safety margin in the engineering calculations of the rate of loss of helium. Two months were the result of favourable circumstances in the launch campaign at Kourou in French Guiana. During a technical check of the Ariane 44P launcher, ISO's engineers seized the chance to recharge the helium, and the quick launch that followed meant that the outer parts of the cryogenic system of the spacecraft had little time to warm up in Kourou's tropical climate. Finally, the daily loss of helium turned out to be 17 less than expected, at the lower end of a range of possibilities considered by the engineers. That gave ISO an estimated five months of additional life. The date for the helium to run out remained somewhat uncertain, and astronomers and engineers have been alert to the possibility of its exhaustion for the past few weeks. The huge bonus to astronomers, from ISO

  14. Hard X-ray observations of ultraluminous infrared galaxies

    NASA Technical Reports Server (NTRS)

    Rieke, G. H.

    1988-01-01

    X-ray flux upper limits of 2-10 keV for ultraluminous infrared galaxies were drawn from the HEAO A-1 data base. The hard X-ray luminosities of these sources are much weaker relative to their total luminosities than would be expected for Seyfert 1 galaxies or quasi-stellar objects. Because of the low level of interstellar extinction for hard X-rays, this result suggests that the ultraluminous galaxies are not powered by embedded QSOs that are otherwise similar to other QSOs. Three other possibilities are: (1) the infrared galaxies may contain a form of X-ray-quiet active nucleus; (2) the X-ray sources in active nuclei may not turn on until after the circumnuclear gas has cleared; or (3) the bulk of the infrared luminosity in these galaxies may be generated by intense circumnuclear star formation.

  15. Hard X-ray observations of ultraluminous infrared galaxies

    SciTech Connect

    Rieke, G.H.

    1988-08-01

    X-ray flux upper limits of 2-10 keV for ultraluminous infrared galaxies were drawn from the HEAO A-1 data base. The hard X-ray luminosities of these sources are much weaker relative to their total luminosities than would be expected for Seyfert 1 galaxies or quasi-stellar objects. Because of the low level of interstellar extinction for hard X-rays, this result suggests that the ultraluminous galaxies are not powered by embedded QSOs that are otherwise similar to other QSOs. Three other possibilities are: (1) the infrared galaxies may contain a form of X-ray-quiet active nucleus; (2) the X-ray sources in active nuclei may not turn on until after the circumnuclear gas has cleared; or (3) the bulk of the infrared luminosity in these galaxies may be generated by intense circumnuclear star formation. 27 references.

  16. Infrared observations of the Saturnian system from Voyager 1

    NASA Technical Reports Server (NTRS)

    Hanel, R.; Conrath, B.; Flasar, F. M.; Kunde, V.; Maguire, W.; Pearl, J.; Pirraglia, J.; Samuelson, R.; Herath, L.; Allison, M.

    1981-01-01

    Atmospheric chemistry analyses of Saturn based on Voyager 1 infrared spectral and radiometric data are presented, including characteristics of the planet's rings and of Titan and other satellites. Infrared spectra of Saturn indicate the presence of H2, CH4, NH3, PH3, C2H2, and C2H6, with the possibility of C3H4 and C3H8. The atmospheric thermal structure of the planet shows hemispheric asymmetries that are consistent with seasonally varying insolation response, with an extensive small-scale latitudinal structure. Atmospheric chemistries of Titan, and optical and thermal characteristics for the rings of Saturn, are also given.

  17. Infrared observations of OB star formation in NGC 6334

    NASA Technical Reports Server (NTRS)

    Harvey, P. M.; Gatley, I.

    1982-01-01

    Infrared photometry and maps from 2 to 100 microns are presented for three of the principal far infrared sources in NGC 6334. Each region is powered by two or more very young stars. The distribution of dust and ionized gas is probably strongly affected by the presence of the embedded stars; one of the sources is a blister H II region, another has a bipolar structure, and the third exhibits asymmetric temperature structure. The presence of protostellar objects throughout the region suggests that star formation has occurred nearly simultaneously in the whole molecular cloud rather than having been triggered sequentially from within.

  18. Infrared observations of OB star formation in NGC 6334

    NASA Technical Reports Server (NTRS)

    Harvey, P. M.; Gatley, I.

    1983-01-01

    Infrared photometry and maps from 2 to 100 microns are presented for three of the principal far infrared sources in NGC 6334. Each region is powered by two or more very young stars. The distribution of dust and ionized gas is probably strongly affected by the presence of the embedded stars; one of the sources is a blister H II region, another has a bipolar structure, and the third exhibits asymmetric temperature structure. The presence of protostellar objects throughout the region suggests that star formation has occurred nearly simultaneously in the whole molecular cloud rather than having been triggered sequentially from within. Previously announced in STAR as N83-16263

  19. Infrared observations of OB star formation in NGC 6334

    NASA Technical Reports Server (NTRS)

    Harvey, P. M.; Gatley, I.

    1983-01-01

    Infrared photometry and maps from 2 to 100 microns are presented for three of the principal far infrared sources in NGC 6334. Each region is powered by two or more very young stars. The distribution of dust and ionized gas is probably strongly affected by the presence of the embedded stars; one of the sources is a blister H II region, another has a bipolar structure, and the third exhibits asymmetric temperature structure. The presence of protostellar objects throughout the region suggests that star formation has occurred nearly simultaneously in the whole molecular cloud rather than having been triggered sequentially from within. Previously announced in STAR as N83-16263

  20. New infrared observations of IRS1, IRS3 and the adjacent nebula in the OMC-2 cluster

    NASA Technical Reports Server (NTRS)

    Pendleton, Y.; Werner, M.; Capps, R.; Dinerstein, H. L.

    1984-01-01

    Near infrared reflection nebulae are often observed around embedded protostellar objects. New observations of the infrared cluster of low luminosity protostars in Orion Molecular Cloud 2 (OMC2) are reported. The asymmetric distribution of the extended emission seen about IRS1 is in fact another infrared reflection nebulae. Observations of near infrared polarimetry, photometry, and spectrophotometry were carried out.

  1. Near-infrared observations of the black hole transient GRS 1716-249.

    NASA Astrophysics Data System (ADS)

    Joshi, Vishal; Vadwale, Santosh; Ganesh, Shashikiran

    2017-03-01

    We report near-infrared photometric observations of GRS 1716-249 during the on-going outburst (ATel #9876, #9895, #10036, #10069). Observations were carried out on UT 20.99 March 2017 with the Mount Abu 1.2 meter telescope (+ PRL Near-Infrared Imager/Spectrograph).

  2. Infrared Observations of Comets Halley and Wilson and Properties of the Grains

    NASA Technical Reports Server (NTRS)

    Hanner, Martha S. (Editor)

    1988-01-01

    The presented papers and discussions at a workshop held at Cornell Univ. are summarized. The infrared observations of Comet Halley and Comet Wilson are reviewed and they are related to optical properties and composition of cometary grains. Relevant laboratory studies are also discussed. Recommendations are made for future infrared comet observations and supporting laboratory investigations.

  3. Infrared Red (IR) Earth Observations taken by Expedition 30 crewmember

    NASA Image and Video Library

    2011-12-25

    ISS030-E-015896 (25 Dec. 2011) --- This is an infrared image of Jakarta, Indonesia at night recorded by an Expedition 30 crew member aboard the Earth-orbiting International Space Station on Dec. 25, 2011. A 58-mm focal length was used.

  4. Infrared Observations of Temperature Modulations on the Hudson River

    NASA Astrophysics Data System (ADS)

    Zuckerman, S.; Anderson, S. P.; Zappa, C. J.; Smith, R. A.

    2011-12-01

    The thermal boundary layer at the surface of a river is constantly disrupted and renewed by physical processes associated with convection, turbulence, wind stress, heat flux, and other environmental factors. These disruptions cause temperature modulations in the surface layer which can be measured with an infrared (IR) sensor. Over the course of two ten-day periods in August and November of 2010, we imaged the Hudson River from atop a nearby cliff using a large-format, mid-wave IR sensor. Time series imagery was collected for 5 to 10 minute periods, every 30 minutes for the entirety of each experiment. In the field of view, several in situ instruments were mounted to a steel piling driven into the river bed. Above and below the water surface, an array of instruments were installed to measure heat flux, wind speed, air and water temperature, current velocity, humidity, radiance, and conductivity. In this analysis, we investigate the relationship between the temperature modulations present in the IR imagery, which are associated with coherent features advecting with the mean flow, and the environmental parameters measured from our in situ instruments. The IR imagery from these experiments show a diverse range of temperature modulation patterns, on scales of 20cm to several tens of meters, often masked by the presence of surface waves. At low grazing angles, the IR images of the water surface are comprised of a combination of emitted radiance from temperature modulations on the surface and reflected radiance from the sky above. To separate out the emitted signal from the reflected signal, we employ a Fourier space filtering technique to exclude the variance in the imagery due to the surface waves. We find the remaining emitted signal to be correlated with wind speed and the air-water temperature difference, and weakly or uncorrelated with stratification and mean current speed. We report on both the signal processing technique used to extract the emitted signal from

  5. Green{close_quote}s function approach to infrared factorization and finite eikonal corrections

    SciTech Connect

    Gellas, G.C.; Karanikas, A.I.; Ktorides, C.N. |

    1997-04-01

    The infrared sector of a generic gauge theory with spin-1/2 matter fields and, for simplicity, only one mass scale, is factored out via a procedure which relies on a path integral (worldline) casting of the field system. The basic idea is to employ a velocity expansion which imposes the spin-1/2 particle{close_quote}s mass as a cutoff for the factorized sector. Anomalous dimensions characterizing the infrared regime are derived in connection with two- and three-point Green{close_quote}s functions. Finally, an off mass shell expansion of the propagator is achieved which contains genuine corrections to the eikonal approximation. {copyright} 1997 Academic Press, Inc.

  6. 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

  7. 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.

  8. Infrared absorption by volcanic stratospheric aerosols observed by ISAMS

    SciTech Connect

    Grainger, R.G.; Lambert, A.; Taylor, F.W.; Remedios, J.J.; Rodgers, C.D.; Corney, M. ); Kerridge, B.J. )

    1993-06-18

    The upper atmosphere research satellite was lofted shortly after the Mt. Pinatubo volcano erupted, and is estimated to have injected 20 million metric tons of sulphur dioxide into the stratosphere. This gas typically is converted to sulphuric acid by interactions with water droplets in the stratosphere. These droplets are typically not saturated in acid density, so the sticking fraction is very high. The improved stratospheric and mesospheric sounder makes measurements in 14 infrared channels from 4 to 17 [mu]m. The authors have used the available infrared data channels to model the distribution and density of sulfuric acid aerosols in the stratospheric band about the equator as a result of this volcanic eruption. Knowing the spectral properties of the aerosol load will aid in modeling the radiative and climatic impacts of this volcanic ejecta.

  9. INFRARED OBSERVATIONAL MANIFESTATIONS OF YOUNG DUSTY SUPER STAR CLUSTERS

    SciTech Connect

    Martínez-González, Sergio; Tenorio-Tagle, Guillermo; Silich, Sergiy

    2016-01-01

    The growing evidence pointing at core-collapse supernovae as large dust producers makes young massive stellar clusters ideal laboratories to study the evolution of dust immersed in a hot plasma. Here we address the stochastic injection of dust by supernovae, and follow its evolution due to thermal sputtering within the hot and dense plasma generated by young stellar clusters. Under these considerations, dust grains are heated by means of random collisions with gas particles which result in the appearance of  infrared spectral signatures. We present time-dependent infrared spectral energy distributions that are to be expected from young stellar clusters. Our results are based on hydrodynamic calculations that account for the stochastic injection of dust by supernovae. These also consider gas and dust radiative cooling, stochastic dust temperature fluctuations, the exit of dust grains out of the cluster volume due to the cluster wind, and a time-dependent grain size distribution.

  10. An airborne infrared spectrometer for solar eclipse observations

    NASA Astrophysics Data System (ADS)

    Samra, Jenna; Cheimets, Peter; DeLuca, Edward; Galeros, John; Gauron, Thomas; Golub, Leon; Guth, Giora; Hertz, Edward; Judge, Philip; Koutchmy, Serge; Marquez, Vanessa

    2016-08-01

    This paper presents the design of an innovative solar spectrometer that will y on the NSF/NCAR Gulfstream V High-Performance Instrumented Airborne Platform for Environmental Research (GV HIAPER) during the 2017 solar eclipse. The airborne infrared spectrometer (AIR-Spec) is groundbreaking in two aspects: it will image infrared coronal emission lines that have never been measured, and it will bring high resolution imaging to GV HIAPER. The instrument development faces the challenges of achieving adequate resolution and signal-to-noise ratio in a compact package mounted to a noisy moving platform. To ensure that AIR-Spec meets its research goals, the instrument is undergoing pre-flight modeling and testing. The results are presented with reference to the instrument requirements.

  11. COBE diffuse infrared background experiment observations of the galactic bulge

    NASA Technical Reports Server (NTRS)

    Weiland, J. L.; Arendt, R. G.; Berriman, G. B.; Dwek, E.; Freudenreich, H. T.; Hauser, M. G.; Kelsall, T.; Lisse, C. M.; Mitra, M.; Moseley, S. H.

    1994-01-01

    Low angular resolution maps of the Galactic bulge at 1.25, 2.2, 3.5, and 4.9 micrometers obtained by the Diffuse Infrared Background Experiment (DIRBE) onboard NASA's Cosmic Background Explorer (COBE) are presented. After correction for extinction and subtraction of an empirical model for the Galactic disk, the surface brightness distribution of the bulge resembles a flattened ellipse with a minor-to-major axis ratio of approximately 0.6. The bulge minor axis scale height is found to be 2.1 deg +/- 0.2 deg for all four near-infrared wavelengths. Asymmetries in the longitudinal distribution of bulge brightness contours are qualitatively consistent with those expected for a triaxial bar with its near end in the first Galactic quadrant (0 deg less than l less than 90 deg). There is no evidence for an out-of-plane tilt of such a bar.

  12. On the performance of infrared sensors in earth observations

    NASA Technical Reports Server (NTRS)

    Johnson, L. F.

    1972-01-01

    The performance of infrared sensing systems is dependent upon the radiative properties of targets in addition to constraints imposed by system components. The unclassified state-of-the-art of infrared system performance figures is reviewed to indicate the relevance to system performance of target radiative properties. A theory of rough surface scattering is developed which allows the formulation of the reflective characteristics of extended targets. The thermal radiation emission from extended targets is formulated on the basis of internal radiation characteristics of natural materials and the transmissive scattering effects at the surface. Finally, the total radiative characteristics may be expressed as functions of material properties and incident and received directions, although the expressions are extremely complex functions and do not account for the effects of shadowing or multiple scattering. It is believed that the theory may be extended to include these effects and to incorporate the local radii of curvature of the surface.

  13. SPITZER OBSERVATIONS OF ABELL 1763. I. INFRARED AND OPTICAL PHOTOMETRY

    SciTech Connect

    Edwards, Louise O. V.; Fadda, Dario; Biviano, Andrea

    2010-02-15

    We present a photometric analysis of the galaxy cluster Abell 1763 at visible and infrared wavelengths. Included are fully reduced images in r', J, H, and K{sub s} obtained using the Palomar 200in telescope, as well as the IRAC and MIPS images from Spitzer. The cluster is covered out to approximately 3 virial radii with deep 24 {mu}m imaging (a 5{sigma} depth of 0.2 mJy). This same field of {approx}40' x 40' is covered in all four IRAC bands as well as the longer wavelength MIPS bands (70 and 160 {mu}m). The r' imaging covers {approx}0.8 deg{sup 2} down to 25.5 mag, and overlaps with most of the MIPS field of view. The J, H, and K{sub s} images cover the cluster core and roughly half of the filament galaxies, which extend toward the neighboring cluster, Abell 1770. This first, in a series of papers on Abell 1763, discusses the data reduction methods and source extraction techniques used for each data set. We present catalogs of infrared sources (with 24 and/or 70 {mu}m emission) and their corresponding emission in the optical (u', g', r', i', z'), and near- to far-IR (J, H, K{sub s} , IRAC, and MIPS 160 {mu}m). We provide the catalogs and reduced images to the community through the NASA/IPAC Infrared Science Archive.

  14. Calculation of positron observables using a finite-element-based approach

    SciTech Connect

    Klein, B. M.; Pask, J. E.; Sterne, P.

    1998-11-04

    We report the development of a new method for calculating positron observables using a finite-element approach for the solution of the Schrodinger equation. This method combines the advantages of both basis-set and real-space-grid approaches. The strict locality in real space of the finite element basis functions results in a method that is well suited for calculating large systems of a thousand or more atoms, as required for calculations of extended defects such as dislocations. In addition, the method is variational in nature and its convergence can be controlled systematically. The calculation of positron observables is straightforward due to the real-space nature of this method. We illustrate the power of this method with positron lifetime calculations on defects and defect-free materials, using overlapping atomic charge densities.

  15. Inference of Ice Cloud Properties from High-spectral Resolution Infrared Observations. Appendix 4

    NASA Technical Reports Server (NTRS)

    Huang, Hung-Lung; Yang, Ping; Wei, Heli; Baum, Bryan A.; Hu, Yongxiang; Antonelli, Paolo; Ackerman, Steven A.

    2005-01-01

    The theoretical basis is explored for inferring the microphysical properties of ice crystal from high-spectral resolution infrared observations. A radiative transfer model is employed to simulate spectral radiances to address relevant issues. The extinction and absorption efficiencies of individual ice crystals, assumed as hexagonal columns for large particles and droxtals for small particles, are computed from a combination of the finite- difference time-domain (FDTD) technique and a composite method. The corresponding phase functions are computed from a combination of FDTD and an improved geometric optics method (IGOM). Bulk scattering properties are derived by averaging the single- scattering properties of individual particles for 30 particle size distributions developed from in situ measurements and for additional four analytical Gamma size distributions for small particles. The non-sphericity of ice crystals is shown to have a significant impact on the radiative signatures in the infrared (IR) spectrum; the spherical particle approximation for inferring ice cloud properties may result in an overest&ation of the optical thickness and an inaccurate retrieval of effective particle size. Furthermore, we show that the error associated with the use of the Henyey-Greenstein phase function can be as larger as 1 K in terms of brightness temperature for larger particle effective size at some strong scattering wavenumbers. For small particles, the difference between the two phase functions is much less, with brightness temperatures generally differing by less than 0.4 K. The simulations undertaken in this study show that the slope of the IR brightness temperature spectrum between 790-960/cm is sensitive to the effective particle size. Furthermore, a strong sensitivity of IR brightness temperature to cloud optical thickness is noted within the l050-1250/cm region. Based on this spectral feature, a technique is presented for the simultaneous retrieval of the visible

  16. Spitzer and near-infrared observations of the young supernova remnant 3C397

    NASA Astrophysics Data System (ADS)

    Rho, Jeonghee; Jarrett, Tom

    2016-06-01

    We present Spitzer IRS, IRAC and MIPS observations and near-infrared imaging and spectroscopy of the young supernova remnant 3C397 (G41.1-0.2). Near-infrared observations were made using the Palomar 200 inch telescope. Both mid- and near-infrared spectra are dominated by Fe lines and near-infrared imaging shows bright Fe emission with a shell-like morphology. There is no molecular hydrogen line belong to the SNR and some are in background. The Ni, Ar, S and Si lines are detected using IRS and hydrogen recombination lines are detected in near-infrared. Two nickel lines at 18.24 and 10.69 micron are detected. 3C397 is ejecta-dominated, and our observations support 3C397 to be a Type Ia supernova.

  17. Interpretation of Mariner 10 infrared observations of Venus

    NASA Technical Reports Server (NTRS)

    Taylor, F. W.

    1975-01-01

    The infrared radiometer experiment on Mariner 10 measured limb-darkening curves for Venus in two spectral intervals, one near 11 microns and the other near 45 microns. These are analyzed in terms of the vertical opacity profile at each wavelength over a limited altitude range, approximately 60 to 80 km above the surface of the planet. Accurate multiple-scattering calculations are used to show that both opacity profiles are consistent with a model containing a cloud of sulphuric acid droplets with radii of 1.1 microns and a small amount of water vapor. Profiles of particle number density and humidity vs height are presented.

  18. Interpretation of Mariner 10 infrared observations of Venus

    NASA Technical Reports Server (NTRS)

    Taylor, F. W.

    1975-01-01

    The infrared radiometer experiment on Mariner 10 measured limb-darkening curves for Venus in two spectral intervals, one near 11 microns and the other near 45 microns. These are analyzed in terms of the vertical opacity profile at each wavelength over a limited altitude range, approximately 60 to 80 km above the surface of the planet. Accurate multiple-scattering calculations are used to show that both opacity profiles are consistent with a model containing a cloud of sulphuric acid droplets with radii of 1.1 microns and a small amount of water vapor. Profiles of particle number density and humidity vs height are presented.

  19. Atmospheric Infrared Sounder on the Earth Observing System

    NASA Technical Reports Server (NTRS)

    Aumann, H. H.

    1995-01-01

    The Atmospheric Infrared Sounder (AIRS) is a high spectral resolution IR spectrometer. AIRS, together with the Advanced Microwave Sounding Unit (AMSU) and the Microwave Humidity Sounder (MHS), is designed to meet the operational weather prediction requirements of the National Oceanic and Atmospheric Administration (NOAA) and the global change research objectives of the National Aeronautics and Space Administration (NASA). The three instruments will be launched in the year 2000 on the EOS-PM spacecraft. Testing of the AIRS engineering model will start in 1996.

  20. Near-Infrared Spectra of IC 59/63 and NGC 1535: Comparing Infrared and Ultraviolet Observations of H2

    NASA Astrophysics Data System (ADS)

    Luhman, M. L.; Luhman, K. L.; Benedict, T.; Jaffe, D. T.; Fischer, J.

    1997-05-01

    We present observations of near-infrared H2 line emission toward the reflection/emission nebulae, IC 59 and IC 63, and the planetary nebula, NGC 1535. Each source has been observed previously in the ultraviolet, where H2 was detected in emission toward IC 63 and in absorption toward NGC 1535. In IC 63, we have detected the 1.601 μm v = 6-4 Q(1), 2.121 μm v = 1-0 S(1), and 2.247 μm v = 2-1 S(1) lines of H2 arising from a near-infrared fluorescent cascade following ultraviolet continuum pumping. The detection marks the first time that both infrared and ultraviolet portions of the H2 fluorescent cascade have been measured in a region exposed to far-ultraviolet continuum photons. Furthermore, we also report 1-0 S(1) and 2-1 S(1) fluorescent emission toward IC 59, a source previously thought to display no H2 fluorescence and considered devoid of molecules based on ultraviolet and CO observations. Toward NGC 1535, we find no H2 emission in the near-infrared, in spite of the reported ultraviolet H2 absorption.

  1. Infrared observations of the jovian system from voyager 2.

    PubMed

    Hanel, R; Conrath, B; Flasar, M; Herath, L; Kunde, V; Lowman, P; Maguire, W; Pearl, J; Pirraglia, J; Samuelson, R; Gautier, D; Gierasch, P; Horn, L; Kumar, S; Ponnamperuma, C

    1979-11-23

    Infrared spectra obtainedfrom Voyager 2 have provided additional data on the Jovian system, complementing those obtained from Voyager 1. The abundance ratio of ethane to acetylene in Jupiter's atmosphere appears to be about three times larger in the polar regions than at lower latitudes. A decidedly hemispherical asymmetry exists, with somewhat higher ratios prevailing in northern latitudes. An overall increase in the abundance ratio by a factor of about 1.7 appears to have occurred between the Voyager 1 and 2 encounters. Global brightness temperature maps of Jupiter at 226 and 602 cm(-1) exhibit a large amount of local- and planetary-scale structure, as well as temporal variability. Although heterogeneous cloud structure and ammonia concentration in the lower troposphere may contribute to the appearance of the 226-cm(-1) map, the detail in the 602-cm(-1) maps probably represents the actual horizontal thermal structure near the tropopause and suggests that dynamical heating and cooling processes are important. Low-latitude surface temperatures on the Galilean satellites rangefrom approximately 80 K on the dark sides to 155 K at the subsolar point on Callisto. Below a thin insulating layer, the thermal inertia of Callisto is somewhat greater than that of Earth's moon. Upper limits on the infrared optical depth of the Jovian ring rangingfrom approximately 3 x 10(-4) at 250 cm(-1) to 3 x 10(-3) at 600 cm(-1) have been found.

  2. Finite temperature infrared spectroscopy of polycyclic aromatic hydrocarbon molecules: Path-integral molecular dynamics

    NASA Astrophysics Data System (ADS)

    Calvo, F.; Parneix, P.; Van-Oanh, N.-T.

    2010-03-01

    The vibrational spectra of the naphthalene, pyrene, and coronene molecules have been computed in the 0-3500 cm-1 infrared range using classical and quantum molecular dynamics simulations based on a dedicated tight-binding potential energy surface. The ring-polymer molecular dynamics (RPMD) and partially adiabatic centroid molecular dynamics (CMD) methods have been employed to account for quantum nuclear effects. The contributions of quantum delocalization to the line shift and broadening are significant in the entire spectral range and of comparable magnitude as pure thermal effects. While the two methods generally produce similar results, the CMD method may converge slower at low temperature with increasing Trotter discretization number. However, and contrary to the CMD method, the RPMD approach suffers from serious resonance problems at high frequencies and low temperatures.

  3. Infrared Observations of the Solar System in Support of Large Aperture Infrared Telescope (LARITS): Calibration. Appendices

    DTIC Science & Technology

    1990-04-01

    Johnson, PH. D., Thomas F. Greene, Ph.D. Students : Frank Lander and Karl J. Vogler Submitted to: Air Force Office of Scientific Research AFOSR/PKO, Bldg...Infrared Emission from Solid- Surfaced Planetary Bodies, a Ph.D. thesis proposal by Karl Vogler, ( 5.6 ) Description of the ADC-I data acquisition and... GRADUATE STUDENT ) 21 R.W.SHORTHILL (PRINCIPAL INVESTIGATOR) 16 APRIL 1986 AA’ COUNTER DRILL A FOR 1/4-20 ALLEN 2.00 0 HEAD SCREW (4 EA) 1- TAP 4-40

  4. Observing temperature fluctuations in humans using infrared imaging

    PubMed Central

    Liu, Wei-Min; Meyer, Joseph; Scully, Christopher G.; Elster, Eric; Gorbach, Alexander M.

    2013-01-01

    In this work we demonstrate that functional infrared imaging is capable of detecting low frequency temperature fluctuations in intact human skin and revealing spatial, temporal, spectral, and time-frequency based differences among three tissue classes: microvasculature, large sub-cutaneous veins, and the remaining surrounding tissue of the forearm. We found that large veins have stronger contractility in the range of 0.005-0.06 Hz compared to the other two tissue classes. Wavelet phase coherence and power spectrum correlation analysis show that microvasculature and skin areas without vessels visible by IR have high phase coherence in the lowest three frequency ranges (0.005-0.0095 Hz, 0.0095-0.02 Hz, and 0.02-0.06 Hz), whereas large veins oscillate independently. PMID:23538682

  5. High-resolution infrared observations of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Pott, Jörg-Uwe

    2012-07-01

    Interferometric resolution at IR wavelengths offers for the first time the possibility to zoom into the nuclei of galaxies beyond the circumnuclear stellar structures and spatially resolve gas and dust in the innermost regions (0.05-5pc), dominated by the central black hole. Ultimate goal is to reveal new aspects of AGN feeding, and interaction with its host galaxy. After first successes of resolving AGN with infrared interferometry (VLTI, Keck-IF), the second generation of high-resolution interferometric imagers behind 8m class telescopes is currently being built. I will summarize current aspects and successes of the field, and present our activities to provide extended capabilities for VLTI-Midi and -Matisse, LBT-Linc-Nirvana and Keck-Astra to study a larger sample of AGN in greater detail.

  6. Decentralized finite-time attitude synchronization for multiple rigid spacecraft via a novel disturbance observer.

    PubMed

    Zong, Qun; Shao, Shikai

    2016-11-01

    This paper investigates decentralized finite-time attitude synchronization for a group of rigid spacecraft by using quaternion with the consideration of environmental disturbances, inertia uncertainties and actuator saturation. Nonsingular terminal sliding mode (TSM) is used for controller design. Firstly, a theorem is proven that there always exists a kind of TSM that converges faster than fast terminal sliding mode (FTSM) for quaternion-descripted attitude control system. Controller with this kind of TSM has faster convergence and reduced computation than FTSM controller. Then, combining with an adaptive parameter estimation strategy, a novel terminal sliding mode disturbance observer is proposed. The proposed disturbance observer needs no upper bound information of the lumped uncertainties or their derivatives. On the basis of undirected topology and the disturbance observer, decentralized attitude synchronization control laws are designed and all attitude errors are ensured to converge to small regions in finite time. As for actuator saturation problem, an auxiliary variable is introduced and accommodated by the disturbance observer. Finally, simulation results are given and the effectiveness of the proposed control scheme is testified.

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  8. HERSCHEL OBSERVATIONS OF FAR-INFRARED COOLING LINES IN INTERMEDIATE REDSHIFT (ULTRA)-LUMINOUS INFRARED GALAXIES

    SciTech Connect

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

    2014-01-20

    We report the first results from a spectroscopic survey of the [C II] 158 μm line from a sample of intermediate redshift (0.2 infrared galaxies, (U)LIRGs (L {sub IR} > 10{sup 11.5} L {sub ☉}), using the Spectral and Photometric Imaging REceiver-Fourier Transform Spectrometer on board the Herschel Space Observatory. This is the first survey of [C II] emission, an important tracer of star formation, at a redshift range where the star formation rate density of the universe increases rapidly. We detect strong [C II] 158 μm line emission from over 80% of the sample. We find that the [C II] line is luminous, in the range (0.8-4) × 10{sup –3} of the far-infrared continuum luminosity of our sources, and appears to arise from photodissociation regions on the surface of molecular clouds. The L{sub [C} {sub II]}/L {sub IR} ratio in our intermediate redshift (U)LIRGs is on average ∼10 times larger than that of local ULIRGs. Furthermore, we find that the L{sub [C} {sub II]}/L {sub IR} and L{sub [CII]}/L{sub CO(1-0)} ratios in our sample are similar to those of local normal galaxies and high-z star-forming galaxies. ULIRGs at z ∼ 0.5 show many similarities to the properties of local normal and high-z star-forming galaxies. Our findings strongly suggest that rapid evolution in the properties of the star-forming regions of (U)LIRGs is likely to have occurred in the last 5 billion years.

  9. Remote Observing at the NASA Infrared Telescope Facility

    NASA Astrophysics Data System (ADS)

    Tokunaga, A. T.; Bus, S. J.; Denault, T.; Hawarden-Ogata, M.

    2003-05-01

    Although remote observations are widely practiced at observatories, the IRTF has recently implemented an approach that allows greater freedom in meeting user needs. Observations at the IRTF can now be supported from sites on the Big Island of Hawaii (Hilo or the mid-level facility) as well as sites anywhere in the world virtually without restriction. Observations are supported throughout the US and even to Paris, France. User requirements are modest: a unix workstation for controlling the instrument and a laptop for communications. For solar system observations, remote observing has been successfully used for synoptic observations (as short as one hour) and programs requiring a number of short observations spread over a semester. In some cases the option to work at sea level rather than the summit of Mauna Kea is essential for health reasons. Further information can be found at: http://irtfweb.ifa.hawaii.edu/userSupport/remote_obs/. We believe this the most flexible remote observing available at any observatory. We acknowledge the support of NASA Cooperative Agreement NCC 5-538.

  10. Near-infrared observations of the z about 2.3 IRAS source FSC 10214 + 4724

    NASA Technical Reports Server (NTRS)

    Soifer, B. T.; Neugebauer, G.; Graham, J. R.; Matthews, K.; Mazzarella, J. M.; Lonsdale, C. J.; Rowan-Robinson, M.; Broadhurst, T.; Lawrence, A.; Mcmahon, R.

    1991-01-01

    Near-infrared imaging and spectroscopy of the extremely luminous IRAS source FSC 10214 + 4724 have been obtained using the Cassegrain infrared camera on the 200-inch Hale Telescope. A low-resolution spectrum in the 2.0-2.4 micron atmospheric window shows a very strong H-alpha line at the optically determined redshift z = 2.286. The observed rest-frame equivalent width of H-alpha is 0.07 +/-0.02 microns, consistent with the largest values found in quasars. The images show an unresolved source, while the near-infrared colors are somewhat redder than the mean colors of quasars observed at the same redshift. The reddening inferred is about 1.5 mag, with an upper limit of about 3.0 mag. If FSC 10214 + 4724 is a quasar, the reddening-corrected bolometric luminosity is approximately equal to the observed infrared luminosity.

  11. Saturn's Atmospheric Composition from Observations by the Cassini/Composite Infrared Spectrometer

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Young, M.; LeClair, A. C.; Achterberg, R. K.; Flasar, F. M.; Kunde, V. G.

    2010-01-01

    Thermal emission infrared observation of Saturn s atmosphere are being made by the Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft since its insertion in Saturn s orbit on July 2nd, 2004. The measurements made in both limb and nadir modes of observations consist of infrared spectra in the 10-1400/cm region with a variable spectral resolution of 0.53/cm and 2.8/cm, and exhibit rotational and vibrational spectral features that may be analyzed for retrieval of the thermal structure and constituent distribution of Saturn s atmosphere. In this paper, we present a comprehensive analysis of the CIRS infrared observed spectra for retrieval of Saturn s atmospheric composition focusing on the distributions of some selected hydrocarbons, phosphine, ammonia, and possible determination of the isotopic ratios of some species with sufficiently strong isolated spectral features. A comparison of the retrieved constituent distributions with the available data in the literature will be made.

  12. Estimating interevent time distributions from finite observation periods in communication networks.

    PubMed

    Kivelä, Mikko; Porter, Mason A

    2015-11-01

    A diverse variety of processes-including recurrent disease episodes, neuron firing, and communication patterns among humans-can be described using interevent time (IET) distributions. Many such processes are ongoing, although event sequences are only available during a finite observation window. Because the observation time window is more likely to begin or end during long IETs than during short ones, the analysis of such data is susceptible to a bias induced by the finite observation period. In this paper, we illustrate how this length bias is born and how it can be corrected without assuming any particular shape for the IET distribution. To do this, we model event sequences using stationary renewal processes, and we formulate simple heuristics for determining the severity of the bias. To illustrate our results, we focus on the example of empirical communication networks, which are temporal networks that are constructed from communication events. The IET distributions of such systems guide efforts to build models of human behavior, and the variance of IETs is very important for estimating the spreading rate of information in networks of temporal interactions. We analyze several well-known data sets from the literature, and we find that the resulting bias can lead to systematic underestimates of the variance in the IET distributions and that correcting for the bias can lead to qualitatively different results for the tails of the IET distributions.

  13. Estimating interevent time distributions from finite observation periods in communication networks

    NASA Astrophysics Data System (ADS)

    Kivelä, Mikko; Porter, Mason A.

    2015-11-01

    A diverse variety of processes—including recurrent disease episodes, neuron firing, and communication patterns among humans—can be described using interevent time (IET) distributions. Many such processes are ongoing, although event sequences are only available during a finite observation window. Because the observation time window is more likely to begin or end during long IETs than during short ones, the analysis of such data is susceptible to a bias induced by the finite observation period. In this paper, we illustrate how this length bias is born and how it can be corrected without assuming any particular shape for the IET distribution. To do this, we model event sequences using stationary renewal processes, and we formulate simple heuristics for determining the severity of the bias. To illustrate our results, we focus on the example of empirical communication networks, which are temporal networks that are constructed from communication events. The IET distributions of such systems guide efforts to build models of human behavior, and the variance of IETs is very important for estimating the spreading rate of information in networks of temporal interactions. We analyze several well-known data sets from the literature, and we find that the resulting bias can lead to systematic underestimates of the variance in the IET distributions and that correcting for the bias can lead to qualitatively different results for the tails of the IET distributions.

  14. Submillimeter and Far-Infrared Observations of the Carina Nebula

    NASA Astrophysics Data System (ADS)

    Oberst, Thomas E.; Parshley, S. C.; Nikola, T.; Stacey, G. J.; Loehr, A.; Lane, A. P.; Stark, A. A.; Kamenetzky, J.

    2011-05-01

    We present the results of a 250 arcmin2 mapping of the 205 μm [NII] fine-structure emission over the northern Carina Nebula, including the Car I and Car II HII regions. Spectra were obtained using the South Pole Imaging Fabry-Perot Interferometer (SPIFI) at the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) at South Pole. We supplement the 205 μm data with new reductions of far-IR fine-structure spectra from the Infrared Space Observatory (ISO) in 63 μm [OI], 122 μm [NII], 146 μm [OI], and 158 μm [CII]. Morphological comparisons are made with optical, radio continuum and CO maps. The 122 [NII] / 205 [NII] line ratio is used to probe the density of the low-ionization gas, and the 158 [C II] / 205 [NII] line ratio is used to probe the fraction of C+ arising from photodissociation regions (PDRs). From the [OI] and [CII] data, we construct a PDR model of Carina following Kaufman et al. (1999). When the PDR properties are compared with other sources, Carina is found to be more akin to 30 Doradus than Galactic star-forming regions such as the Orion Bar, M17, or W49; this is consistent with the view of Carina as a more evolved region, where much of the parent molecular cloud has been ionized or swept away. These data constitute the first ever ground-based detection of the 205 μm [NII] line, and only the third detection overall since those of the COBE FIRAS and the KAO in the early 1990s.

  15. Retrieval of CFC concentrations from thermal infrared spectrum observed by Greenhouse gases Observation SATellite (GOSAT)

    NASA Astrophysics Data System (ADS)

    Inagoya, A.; Imasu, R.; Hayashi, Y.

    2011-12-01

    Chemical substances emitted by the anthropological activities cause serious environmental problems. Among them, CFCs have been depleting ozone layer in the stratosphere. Also, it is reported that their radiative forcing is 0.268 W/m2 and they could largely account for global warming. To mitigate these problems, it is important to estimate their distribution and amount globally with good accuracy. Though on site measurements provide considerably precise data, the observation sites are quite limited. In contrast, results retrieved from data obtained by remote sensing may contain more errors, but its wide spatial coverage is great advantage to monitor atmosphere globally and continuously for long term. The purpose of this study is to retrieve concentrations of CFC-11 and CFC-12, and replacements for CFCs from thermal infrared spectrum data obtained by Greenhouse gases Observation SATellite (GOSAT). We use spectrum data taken from its main sensor, Fourier transform spectrometer TANSO-FTS, particularly its band 4 (5.5 - 14.3μm). The sub-sensor called TANSO-CAI is used for cloud screening. To calculate simulated spectrum using a radiative transfer model, LBLRTM, the meteorological reanalysis data including atmospheric information at each point such as surface temperature and atmospheric composition are prepared. As the first step, we focus on CFC-11 and CFC-12 which have strong absorption band near 850 cm-1 and 920 cm-1 respectably. For retrieving the gases, the baselines of the observed and calculated spectrum need to be matched. However, it is not always true due to the uncertainty of information in the reanalysis data. To match baselines, we first set the constant emissivity and estimate the surface temperature. Even after the procedure, spectral residue still remained particularly on the peaks of water vapor absorption lines. We will retrieve more precise surface temperature and the amount of water vapor from observed each spectrum so that we could get better a

  16. Observation of Aubry-type transition in finite atom chains via friction.

    PubMed

    Bylinskii, Alexei; Gangloff, Dorian; Counts, Ian; Vuletić, Vladan

    2016-07-01

    The highly nonlinear many-body physics of a chain of mutually interacting atoms in contact with a periodic substrate gives rise to complex static and dynamical phenomena, such as structural phase transitions and friction. In the limit of an infinite chain incommensurate with the substrate, Aubry predicted a transition with increasing substrate potential, from the chain's intrinsic arrangement free to slide on the substrate, to a pinned arrangement favouring the substrate pattern. So far, the Aubry transition has not been observed. Here, using spatially resolved position and friction measurements of cold trapped ions in an optical lattice, we observed a finite version of the Aubry transition and the onset of its hallmark fractal atomic arrangement. Notably, the observed critical lattice depth for few-ion chains agrees well with the infinite-chain prediction. Our results elucidate the connection between competing ordering patterns and superlubricity in nanocontacts-the elementary building blocks of friction.

  17. Observation of enhanced visible and infrared emissions in photonic crystal thin-film light-emitting diodes

    SciTech Connect

    Cheung, Y. F.; Li, K. H.; Hui, R. S. Y.; Choi, H. W.

    2014-08-18

    Photonic crystals, in the form of closed-packed nano-pillar arrays patterned by nanosphere lithography, have been formed on the n-faces of InGaN thin-film vertical light-emitting diodes (LEDs). Through laser lift-off of the sapphire substrate, the thin-film LEDs conduct vertically with reduced dynamic resistances, as well as reduced thermal resistances. The photonic crystal plays a role in enhancing light extraction, not only at visible wavelengths but also at infrared wavelengths boosting heat radiation at high currents, so that heat-induced effects on internal quantum efficiencies are minimized. The observations are consistent with predictions from finite-difference time-domain simulations.

  18. Observation of enhanced visible and infrared emissions in photonic crystal thin-film light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Cheung, Y. F.; Li, K. H.; Hui, R. S. Y.; Choi, H. W.

    2014-08-01

    Photonic crystals, in the form of closed-packed nano-pillar arrays patterned by nanosphere lithography, have been formed on the n-faces of InGaN thin-film vertical light-emitting diodes (LEDs). Through laser lift-off of the sapphire substrate, the thin-film LEDs conduct vertically with reduced dynamic resistances, as well as reduced thermal resistances. The photonic crystal plays a role in enhancing light extraction, not only at visible wavelengths but also at infrared wavelengths boosting heat radiation at high currents, so that heat-induced effects on internal quantum efficiencies are minimized. The observations are consistent with predictions from finite-difference time-domain simulations.

  19. CALCULATION OF INTENSITY RATIOS OF OBSERVED INFRARED [Fe II] LINES

    SciTech Connect

    Deb, Narayan C.; Hibbert, Alan

    2010-03-10

    Two recent observational studies of the [Fe II] {lambda}12567/{lambda}16435 line ratio by Smith and Hartigan and Rodriguez-Ardila et al. have suggested that the available theoretical A-values could be incorrect to 10%-40%. We have carried out an extensive configuration interaction calculation of [Fe II] lines to investigate this claim, as well as the variability in observed line ratios for {lambda}8617/{lambda}9052 and {lambda}8892/{lambda}9227 of Dennefeld. For these transitions, we are generally in good agreement with the results of Nussbaumer and Storey, less so with those of Quinet et al. In comparison, the ratios derived from observations appear either to be less secure, or other factors influence those results.

  20. Characterizing asteroids multiply-observed at infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Koren, Seth C.; Wright, Edward L.; Mainzer, A.

    2015-09-01

    We report Markov chain Monte Carlo fits of the thermophysical model of Wright (Wright, E.L. [2007]. Astrophysics e-prints arXiv:astro-ph/0703058) to the fluxes of 10 asteroids which have been observed by both WISE and NEOWISE. This model is especially useful when one has observations of an asteroid at multiple epochs, as it takes advantage of the views of different local times and latitudes to determine the spin axis and the thermal parameter. Many of the asteroids NEOWISE observes will have already been imaged by WISE, so this proof of concept shows there is an opportunity to use a rotating cratered thermophysical model to determine surface thermal properties of a large number of asteroids.

  1. Collision of comet Shoemaker-Levy 9 with Jupiter observed by the NASA infrared telescope facility

    NASA Technical Reports Server (NTRS)

    Orton, G.; A'Hearn, M.; Baines, K.; Deming, D.; Dowling, T.; Goguen, J.; Griffith, C.; Hammel, H.; Hoffmann, W.; Hunten, D.; Zahnle, K. (Principal Investigator)

    1995-01-01

    The National Aeronautics and Space Administration (NASA) Infrared Telescope Facility was used to investigate the collision of comet Shoemaker-Levy 9 with Jupiter from 12 July to 7 August 1994. Strong thermal infrared emission lasting several minutes was observed after the impacts of fragments C, G, and R. All impacts warmed the stratosphere and some the troposphere up to several degrees. The abundance of stratospheric ammonia increased by more than 50 times. Impact-related particles extended up to a level where the atmospheric pressure measured several millibars. The north polar near-infrared aurora brightened by nearly a factor of 5 a week after the impacts.

  2. Collision of comet Shoemaker-Levy 9 with Jupiter observed by the NASA infrared telescope facility.

    PubMed

    Orton, G; A'Hearn, M; Baines, K; Deming, D; Dowling, T; Goguen, J; Griffith, C; Hammel, H; Hoffmann, W; Hunten, D

    1995-03-03

    The National Aeronautics and Space Administration (NASA) Infrared Telescope Facility was used to investigate the collision of comet Shoemaker-Levy 9 with Jupiter from 12 July to 7 August 1994. Strong thermal infrared emission lasting several minutes was observed after the impacts of fragments C, G, and R. All impacts warmed the stratosphere and some the troposphere up to several degrees. The abundance of stratospheric ammonia increased by more than 50 times. Impact-related particles extended up to a level where the atmospheric pressure measured several millibars. The north polar near-infrared aurora brightened by nearly a factor of 5 a week after the impacts.

  3. Infrared, submillimeter, and millimeter observations of the soft gamma-ray repeaters

    NASA Technical Reports Server (NTRS)

    Smith, I. A.; Joyce, R.; Schultz, A. S. B.; Hurley, K.; Vrba, F. J.; Hartmann, D.; Kouveliotou, C.; vanParadijs, J.; Waters, L. B. F. M.; Chernin, L. M.; Durouchoux, P.; Corbel, S.; Wallyn, P.

    1997-01-01

    Soft gamma ray repeaters appear to be a new class of neutron stars. While a counterpart to SGR 0525-66 was detected uniquely in the X-ray band, SGR 1806-20 and SGR 1900+14 have unusual stellar counterparts whose spectra peak in the infrared. The infrared spectra appear to contain several components: the photospheric emission from stars dominates at shorter wavelengths; a bright point source dominates at 25 micrometers, and an extended source dominates at 60 micrometers. The longer wavelength spectra are inconsistent with mono-energetic synchrotron and black body radiation models. Recent millimeter, submillimeter and infrared observations are reviewed. A preliminary analysis of the higher resolution infrared spectra of SGR 1806-20 and SGR 1900+14 is outlined. These confirm previous observations suggesting that SGR1806-20 has an outflow and that the stars comprising the counterpart to SGR 1900+14 have very similar spectra.

  4. 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.

  5. 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.

  6. Millimetre observations of infrared carbon stars. I. The data

    NASA Astrophysics Data System (ADS)

    Groenewegen, M. A. T.; Sevenster, M.; Spoon, H. W. W.; Pérez, I.

    2002-08-01

    Millimetre observations of IRAS selected red carbon stars are presented. About 260 stars have been observed with SEST and IRAM in the CO (1-0) and CO (2-1) lines and partially in HCN (1-0) and SiO (3-2). An overall detection rate, in at least one line, of about 80% is achieved. The survey represents the second largest survey for AGB stars, and the largest ever for carbon stars. Two new detections in SiO (3-2) in carbon stars are reported. When available, the SiO/HCN and HCN/CO (1-0) line ratios are consistent with the ratios expected for carbon stars. Based on observations collected at the European Southern Observatory, La Silla, Chile within program ESO 60.E-0103, 62.L-0128, 64.L-0012 and 66.D-0027. Also based on observations with the IRAM telescope, Granada, Spain under programs 98-97, 141-97 and 010-99. The complete Fig. 1 is only available in electronic form at http://www.edpsciences.org. The complete Table 3 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/390/501

  7. 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.

  8. 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.

  9. Infrared sky noise survey. [over observing sites in the U.S., Mexico, and Chile

    NASA Technical Reports Server (NTRS)

    Westphal, J. A.

    1974-01-01

    A 10 micron infrared sky noise survey, which was conducted during the period from June 1, 1970 to June 30, 1974, is reported along with associated electronics and recording equipment which was developed and deployed for periods up to 18 months at various potential or existing infrared observing sites in the U.S., Mexico, and Chile. The results of the data activity are given, and variables are defined which influence the intensity and duration of the sky noise.

  10. Nighttime reactive nitrogen measurements from stratospheric infrared thermal emission observations

    NASA Technical Reports Server (NTRS)

    Abbas, Mian M.; Kunde, Virgil G.; Brasunas, J. C.; Herman, J. R.; Massie, Steven T.

    1991-01-01

    IR thermal emission spectra of the earth's atmosphere in the 700-2000/cm region were obtained with a cryogenically cooled high-resolution interferometer spectrometer on a balloon flight from Palestine, Texas, on September 15-16, 1986. The observations exhibit spectral features of a number of stratospheric constituents, including important species of the reactive nitrogen family. An analysis of the observed data for simultaneously measured vertical distributions of O3, H2O, N2O, NO2, N2O5, HNO3, and ClONO2 is presented. These measurements permit the first direct determination of the nighttime total reactive nitrogen concentrations, and the partitioning of the important elements of the NO(x) family. Comparisons of the total reactive nitrogen budget are made with the measurements by the ATMOS experiment and with the predictions of one-dimensional and two-dimensional photochemical models.

  11. High-resolution, far-infrared observations of NGC 2071

    NASA Technical Reports Server (NTRS)

    Butner, Harold M.; Evans, Neal J., II; Harvey, Paul M.; Mundy, Lee G.; Natta, Antonella

    1990-01-01

    The far-IR emission of the visible reflection nebula NGC 2071 has been resolved at both 50 and 100 microns along several directions. The observations reveal an extended, roughly spherical source with an average source diameter of about 12 arcsec or 4700 AU at 50 microns and about 16 arcsec or 6200 AU at 100 microns. The source is modeled using a radiative transport code to match scans of the source and previous photometry. The luminosity of the source is 520 solar at a distance of 390 pc. The optical depth at 100 microns is 0.20, implying a mass of 1.2-10 solar within a radius of 5900 AU. The density gradient is in good agreement with theoretical models for infalling envelopes around protostars and in reasonable agreement with other observational determinations.

  12. Solution of nonlinear finite difference ocean models by optimization methods with sensitivity and observational strategy analysis

    NASA Technical Reports Server (NTRS)

    Schroeter, Jens; Wunsch, Carl

    1986-01-01

    The paper studies with finite difference nonlinear circulation models the uncertainties in interesting flow properties, such as western boundary current transport, potential and kinetic energy, owing to the uncertainty in the driving surface boundary condition. The procedure is based upon nonlinear optimization methods. The same calculations permit quantitative study of the importance of new information as a function of type, region of measurement and accuracy, providing a method to study various observing strategies. Uncertainty in a model parameter, the bottom friction coefficient, is studied in conjunction with uncertain measurements. The model is free to adjust the bottom friction coefficient such that an objective function is minimized while fitting a set of data to within prescribed bounds. The relative importance of the accuracy of the knowledge about the friction coefficient with respect to various kinds of observations is then quantified, and the possible range of the friction coefficients is calculated.

  13. Solution of nonlinear finite difference ocean models by optimization methods with sensitivity and observational strategy analysis

    NASA Technical Reports Server (NTRS)

    Schroeter, Jens; Wunsch, Carl

    1986-01-01

    The paper studies with finite difference nonlinear circulation models the uncertainties in interesting flow properties, such as western boundary current transport, potential and kinetic energy, owing to the uncertainty in the driving surface boundary condition. The procedure is based upon nonlinear optimization methods. The same calculations permit quantitative study of the importance of new information as a function of type, region of measurement and accuracy, providing a method to study various observing strategies. Uncertainty in a model parameter, the bottom friction coefficient, is studied in conjunction with uncertain measurements. The model is free to adjust the bottom friction coefficient such that an objective function is minimized while fitting a set of data to within prescribed bounds. The relative importance of the accuracy of the knowledge about the friction coefficient with respect to various kinds of observations is then quantified, and the possible range of the friction coefficients is calculated.

  14. Mid-Infrared Observations of the Galactic Center

    NASA Technical Reports Server (NTRS)

    Stolovy, Susan

    1997-01-01

    Under this grant, Susan Stolovy completed her thesis work and performed an analysis of the galactic center. For her thesis Susan analyzed observations of the galactic center obtained with the KAO using the KEGS spectrograph, built at Cornell. These observations present a study of the distribution and kinematics of the atomic gas in the inner few parsecs of the Galaxy as traced by the forbidden [SiII] line at 34.814 microns. The integrated [SiII] emission peaks near Sgr A* and extends past the inner edge of the Circumnuclear Disk (CND), passing through a gap in the dense molecular material to the northwest. The [SiII] maps have a spatial resolution of 15" and a spectral resolution of 50 km/s. The spectra, which are characterized by broad linewidths of order 100 km/s, are kinematically consistent with the CND rotation to the southwest but not to the north. The northern extension may be experiencing shocks and is likely to be infalling along the Northern Arm. Observations of high [Sill]/ [OI] and [SiII]/dust continuum ratios support the conjecture that turbulent motions and shocks in the inner few parsecs of the Galaxy are destroying dust grains, thus elevating the abundance of atomic silicon.

  15. How Well Can Infrared Sounders Observe the Atmosphere and Surface Through Clouds?

    NASA Technical Reports Server (NTRS)

    Zhou, Daniel K.; Larar, Allen M.; Liu, Xu; Smith, William L.; Strow, L. Larrabee; Yang, Ping

    2010-01-01

    Infrared sounders, such as the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared sounder (CrIS), have a cloud-impenetrable disadvantage in observing the atmosphere and surface under opaque cloudy conditions. However, recent studies indicate that hyperspectral, infrared sounders have the ability to detect cloud effective-optical and microphysical properties and to penetrate optically thin clouds in observing the atmosphere and surface to a certain degree. We have developed a retrieval scheme dealing with atmospheric conditions with cloud presence. This scheme can be used to analyze the retrieval accuracy of atmospheric and surface parameters under clear and cloudy conditions. In this paper, we present the surface emissivity results derived from IASI global measurements under both clear and cloudy conditions. The accuracy of surface emissivity derived under cloudy conditions is statistically estimated in comparison with those derived under clear sky conditions. The retrieval error caused by the clouds is shown as a function of cloud optical depth, which helps us to understand how well infrared sounders can observe the atmosphere and surface through clouds.

  16. Direct infrared observation of hydrogen chloride anions in solid argon.

    PubMed

    Huang, Tzu-Ping; Chen, Hui-Fen; Liu, Meng-Chen; Chin, Chih-Hao; Durrant, Marcus C; Lee, Yin-Yu; Wu, Yu-Jong

    2017-09-21

    To facilitate direct spectroscopic observation of hydrogen chloride anions (HCl(-)), electron bombardment of CH3Cl diluted in excess Ar during matrix deposition was used to generate this anion. Subsequent characterization were performed by IR spectroscopy and quantum chemical calculations. Moreover the band intensity of HCl(-) decays slowly when the matrix sample is maintained in the dark for a prolonged time. High-level ab inito calculation suggested that HCl(-) is only weakly bound. Atom-in-molecule charge analysis indicated that both atoms of HCl(-) are negatively charged and the Cl atom is hypervalent.

  17. Direct infrared observation of hydrogen chloride anions in solid argon

    NASA Astrophysics Data System (ADS)

    Huang, Tzu-Ping; Chen, Hui-Fen; Liu, Meng-Chen; Chin, Chih-Hao; Durrant, Marcus C.; Lee, Yin-Yu; Wu, Yu-Jong

    2017-09-01

    To facilitate direct spectroscopic observation of hydrogen chloride anions (HCl-), electron bombardment of CH3Cl diluted in excess Ar during matrix deposition was used to generate this anion. Subsequent characterization were performed by IR spectroscopy and quantum chemical calculations. Moreover the band intensity of HCl- decays slowly when the matrix sample is maintained in the dark for a prolonged time. High-level ab inito calculation suggested that HCl- is only weakly bound. Atom-in-molecule charge analysis indicated that both atoms of HCl- are negatively charged and the Cl atom is hypervalent.

  18. GOES imager visible-to-infrared channel registration using star observations

    NASA Astrophysics Data System (ADS)

    Chu, Donald; Baucom, Jeanette G.; Baltimore, Perry; Bremer, James C.

    2003-11-01

    Due to optical misalignment, visible and infrared channels of the Geostationary Operational Environmental Satellite (GOES) I-M Imager may not be properly registered. This "co-registration" error is currently estimated by comparing groups of visible and infrared observation residuals from the GOES Orbit and Attitude Tracking System (OATS). To make the channel-to-channel comparison more direct, it was proposed to compare individual observations rather than groups of observations. This has already been done for landmarks but not for stars. Stars would help determine nighttime co-registration when visible landmarks are not available. Although most stars in the GOES catalog are not detectable in the shortwave infrared channel, many are. Because stars drift west-to-east across the detectors and because of their high observation frequency, stars provide good east-west co-registration information. Due to the large detector fields-of-view, stars do not provide much information about north-south co-registration.

  19. Cumulus convection as observed from an airborne infrared radiometer

    NASA Technical Reports Server (NTRS)

    Szejwach, G.; Simpson, J.

    1982-01-01

    The implementation of high resolution passive radiative remote sensing of the cloudiness volume in the atmospheric window between 10.5-12.5 microns is described. Airborne radiometers, the NASA/Cloud Top Scanner, were used to obtain radiances during several passages over two merging cumulus clouds, with the data being converted into equivalent blackbody temperatures. Data were also gathered in the 0.55-0.70 micron visible bands as part of the SESAME-79 experiment. The number of points observed in the IR channel were adjusted to account for the viewing angle and areal extents were calculated. A relationship was assumed to exist between the brightness temperatures of the cloud surface and the level of cloudiness at a given atmospheric altitude. Further measurements with lidar scans are indicated in order to reduce the error levels associated with the method.

  20. Infrared observations of circumstellar ammonia in OH/IR supergiants

    SciTech Connect

    McLaren, R.A.; Betz, A.L.

    1980-09-15

    Ammonia has been detected in the circumstellar envelopes of VY Canis Majoris, VX Sagittarii, and IRC+10420 by means of several absorption lines in the ..nu../sub 2/ vibration-rotation band near 950 cm/sup -1/. The line profiles are well resolved (0.2 km s/sup -1/ resolution) and show the gas being accelerated to terminal expansion velocities near 30 km s/sup -1/. The observations reveal a method for determining the position of the central star on VLBI maps of OH maser emission to an accuracy of approx.0''.2. A firm lower limit of 2 x 10/sup 15/ cm/sup -2/ is obtained for the NH/sub 3/ column density in VY Canis Majoris.

  1. Infrared observations of circumstellar ammonia in OH/IR supergiants

    NASA Technical Reports Server (NTRS)

    Mclaren, R. A.; Betz, A. L.

    1980-01-01

    Ammonia has been detected in the circumstellar envelopes of VY Canis Majoris, VX Sagittarii, and IRC +10420 by means of several absorption lines in the nu-2 vibration-rotation band near 950 kaysers. The line profiles are well resolved (0.2 km/sec resolution) and show the gas being accelerated to terminal expansion velocities near 30 km/sec. The observations reveal a method for determining the position of the central star on VLBI maps of OH maser emission to an accuracy of approximately 0.2 arcsec. A firm lower limit of 2 x 10 to the 15th/sq cm is obtained for the NH3 column density in VY Canis Majoris.

  2. CoCo: an infrared cold coronagraph for astronomical observations

    NASA Astrophysics Data System (ADS)

    Wang, Shu-I.; Owensby, Pamela D.; Toomey, Douglas W.; Brown, Robert H.; Stahlberger, Werner E.; Cavedoni, Charles P.; Hua, Rong; Ftaclas, Christ

    1994-06-01

    This paper describes the design of an IR cold coronagraph (CoCo) built by SETS Technology, Inc., for use at the NASA 3 m IR Telescope Facility (IRTF) at Mauna Kea Observatory, for the imaging of faint IR sources in proximity to bright sources. The coronagraph is designed to obtain high contrast photometric images by use of an occulting mask and a pupil mask. The coronagraph is to be used in combination with the IRTF NSFCAM, which covers 1-5 micrometers and uses a 256x256 InSb array. The platescale can be varied from 0.06'/pixel to 0.15'/pixel, covering a field of view of 14' and 38', respectively. Selectable apodized and hard occulting masks are mounted on a wheel as the first element in the system to reduce scattered light. Selectable pupil masks are cooled to 77K within the CoCo cryostat. The cryostat consists of a liquid nitrogen can for cooling the optics, masks, and baffles. The CoCo dewar is mounted on a slide in a housing to allow it to move out of the beam path so that the NSFCAM may be used with or without the coronagraph during the same observing period.

  3. 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.

  4. OSSE observations of the ultraluminous infrared galaxies ARP 220 and MRK 273

    NASA Technical Reports Server (NTRS)

    Dermer, C. D.; Shier, L. M.; Sturner, S. J.; McNaron-Brown, K.; Bland-Hawthorn, J.

    1997-01-01

    The results of oriented scintillation spectrometer experiment (OSSE) observations of the ultraluminous infrared galaxies Arp 220 and Mrk 273 are reported. The pointings of Arp 220 and Mrk 273 concentrated on their upper limits. The gamma ray luminosities from these sources were found to be between one and two orders of magnitude smaller than the infrared luminosities. Multiwavelength luminosity spectra are produced from the radio to the gamma ray regime, and are compared with the typical multiwavelength spectra of active galactic nuclei. The lack of measured gamma ray emission provides no evidence for the existence of buried active galactic nuclei in these ultraluminous infrared galaxies, but is consistent with an origin of the infrared luminosity from starburst activity.

  5. Analysis and Design of Robust H∞ Fault Estimation Observer With Finite-Frequency Specifications for Discrete-Time Fuzzy Systems.

    PubMed

    Zhang, Ke; Jiang, Bin; Shi, Peng; Xu, Jinfa

    2015-07-01

    This paper addresses the problem of fault estimation observer design with finite-frequency specifications for discrete-time Takagi-Sugeno (T-S) fuzzy systems. First, for such T-S fuzzy models, an H∞ fault estimation observer with pole-placement constraint is proposed to achieve fault estimation. Based on the generalized Kalman-Yakubovich-Popov lemma, the given finite-frequency observer possesses less conservatism compared with the design of the entire-frequency domain. Furthermore, the performance of the presented fault estimation observer is further enhanced by adding the degree of freedom. Finally, two examples are presented to illustrate the effectiveness of the proposed strategy.

  6. Simulation of Satellite Observations of Induced Magnetic Fields using Scripted Finite Element Methods

    NASA Astrophysics Data System (ADS)

    Ribaudo, J. T.; Constable, C.; Parker, R. L.

    2009-12-01

    Scripted finite element methods allow flexible investigations of the influence of asymmetric external source fields and 3-dimensional (3D) internal electrical conductivity structure in the problem of global geomagnetic depth sounding. Our forward modeling is performed in the time and frequency domains via FlexPDE, a commercial finite element modeling package, and the technique has been validated against known solutions to 3D steady state and time-dependent problems. The induction problem is formulated in terms of the magnetic vector potential and electric scalar potential, and mesh density is managed both explicitly and through adaptive mesh refinement. We investigate the effects of 3D Earth conductivity on both satellite and ground-based magnetic field observations in the form of a geographically varying conductance map of the crust and oceans overlying a radially symmetric core and mantle. This map is used in conjunction with a novel boundary condition based on Ampere's Law to model variable near-surface induction without the computational expense of a 3D crust/ocean mesh and is valid for magnetic signals in the frequency range of interest for satellite induction studies. The simulated external magnetic field is aligned with Earth's magnetic pole, rather than its rotational pole, and increases in magnitude along the Earth/Sun axis. Earth rotates through this field with a period of 24 hours. Electromagnetic c-responses estimated from satellite data under the assumption that the primary and induced fields are dipolar in structure are known to be biased with respect to local time. We investigate the influence of Earth's rotation through the non-uniform external field on these c-responses, to determine whether this can explain the observed local time bias.

  7. Further joint X-ray, infrared and radio observations of Cygnus X-3

    NASA Technical Reports Server (NTRS)

    Mason, K. O.; Becklin, E. E.; Blankenship, L.; Brown, R. L.; Elias, J.; Hjellming, R. M.; Matthews, K.; Murdin, P. G.; Neugebauer, G.; Sanford, P. W.

    1975-01-01

    Observations of Cygnus X-3 were carried out at 2.5 - 7.5 keV, 2.2 micron, 8.1 GHz and 2.7 GHz over a two week period. The X-ray data show the periodic structure which is typical of Cyg X-3. At times the X-ray and infrared measurements show very similar periodic structure, both in phase and shape, while at other times the infrared data show no periodic variability. The radio fluxes were usually low during the period of observation; both the daily average radio flux levels and spectral index remained nearly constant.

  8. The thermal structure of Saturn: Inferences from ground-based and airborne infrared observations

    NASA Technical Reports Server (NTRS)

    Tokunaga, A.

    1978-01-01

    Spectroscopic and photometric infrared observations of Saturn are reviewed and compared to the expected flux from thermal structure models. Large uncertainties exist in the far-infrared measurements, but the available data indicate that the effective temperature of the disk of Saturn is 90 + or - 5 K. The thermal structure models proposed by Tokunaga and Cess and by Gautier et al. (model 'N') agree best with the observations. North-South limb scans of Saturn at 10 and 20 micrometers show that the temperature inversion is much stronger at the South polar region than at the equator.

  9. Infrared Spectra of (CO2)2-OCS Complex: Infrared Observation of Two Distinct Barrel-Shaped Isomers

    NASA Astrophysics Data System (ADS)

    Norooz Oliaee, J.; Dehghany, M.; Mivehvar, F.; Moazzen-Ahmadi, N.; McKellar, A. R. W.

    2010-06-01

    Spectra of (CO2)2-OCS complex in the region of the OCS ν 1 fundamental (˜ 2062 cm-1) are observed using a tunable diode laser to probe a pulsed supersonic slit jet expansion. A previous microwave study of the complex by Peebles and Kuczkowskia gave a distorted triangular cylinder. The geometerical disposition of the three dimer faces of this trimer are quite similar to the slipped CO2 dimer, the lowest energy form of OCS-CO2 (isomer a), also observed and analyzed in the microwave region, and the higher energy form of OCS-CO2 (isomer b), first observed by our group in the infrared region. Here we report the observation and analysis of two infrared bands, corresponding to two distinct isomers of the (CO2)2-OCS complex. A band around 2058.8 cm-1 was assigned to isomer I, which is the same as that studied previously by microwave spectroscopy. A second band around 2051.7 cm-1 was assigned to a higher energy isomer of the complex, isomer II, has not been observed previously, but expected on the basis of ab initio calculations. Approximate structural parameters for this new isomer were obtained by means of isotopic substitution. In contrast to isomer I, the geometerical disposition of the faces containing OCS and CO2 in isomer II are similar to isomer b of the OCS-CO2 complex. S. A. Peebles and R. L. Kuczkowski, J. Chem. Phys. 109, 5277 (1998). S. E. Novick, R. D. Suenram, and F. J. Lovas, J. Chem. Phys. 88, 687 (1988). M. Dehghany, J. Nooroz Oliaee, M. Afshari, N. Moazzen-Ahmadi, and A. R. W. McKellar, J. Chem. Phys. 130, 224310 (2009). H. Valdés and J. A. Sordo, Int. J. Comput. Chem. 23, 444 (2002).

  10. Io's volcanic enhancement observed in mid-infrared from the ground

    NASA Astrophysics Data System (ADS)

    Yoneda, M.; Miyata, T.; Tang, C. C. C.; Sako, S.; Kamizuka, T.; Nakamura, T.; Asano, K.; Uchiyama, M.; Okada, K.; Yoshii, Y.; Sakanoi, S.; Kasaba, Y.; Okano, S.

    2014-04-01

    We present new ground-based observations of Io's volcanic activity made in 2011 and 2012 using a 1-m telescope, at mid-infrared wavelengths where Io's thermal radiation dominates solar reflected light seen at shorter wavelengths. The emitted power from Daedalus in 2011 was estimated to be ~1013 (W). This level of power has never been observed from Daedalus from previous observations, and is almost as powerful as the lava lake Loki Patera, the most powerful hotspot on Io. However, the angular separation between Loki and Daedalus is only 0.1 arcsec at most. This means most of the ground-based telescopes cannot observe these two hotspots individually at infrared wavelengths. The possibility that the power of Daedalus has been underestimated should be noted. Previous thermal measurements from ground-based observations of Loki might be overestimated, as they may also include the thermal emissions from Daedalus as well. The diffraction limit in the mid-infrared range using a 1-m diameter telescopes is significantly larger than the angular size of Io from the ground. However, this study successfully distinguished a hotspot on Io by focusing on light curves that show Io's radiance as a function of Io's central longitude. The potential of small telescopes with infrared detectors for observing Io's volcanic activity should also be noted.

  11. Tropical Storm Beryl as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Figure 1: AIRS Microwave Image

    This is an infrared image of Tropical Storm Beryl in the western Atlantic, from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite on July 20, 2006, 1:30 am local time. This AIRS image shows the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of the hurricane. The infrared signal does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red). This infrared image shows three large regions of strong convection surrounding the core of the storm. The largest, on the northern edge of the core, also appears in the companion microwave image to contain intense precipitation.

    The image in figure 1 is created from microwave radiation emitted by Earth's atmosphere and received by the instrument. It shows where the heaviest rainfall is taking place (in blue) in the storm. Blue areas outside of the tropical storm, where there are either some clouds or no clouds indicate where the sea surface shines through.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a

  12. 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.

  13. The nature of AFGL 2591 and its associated molecular outflow: Infrared and millimeter-wave observations

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    The results of infrared photometry from 2 to 160 microns of AFGL and CO(12) observations of its associated molecular cloud and high velocity molecular outflow are presented and discussed. The observed solar luminosity is 6.7 x 10(4) at a distance of 2 kpc. The spectrum of AFGL 2591 is interpreted in the context of a model in which a single embedded object is the dominant source of the infrared luminosity. This object is determined to be surrounded by a compact, optically thick dust shell with a temperature in excess of several hundred degrees kelvin. The extinction to this source is estimated to be between 26 and 50 visual magnitudes. The absolute position of the infrared sources at 10 microns was determined to an accuracy of + or in. This indicates for the first time that the IR source and H2O source are not coincident. The CO(12) observations show the high-velocity molecular flow near AFGL 2591 to be extended, bipolar and roughly centered on the infrared emission. The observations suggest that the red-shifted flow component extends beyond the boundary of the ambient cloud within which AFGL 2591 is embedded. The CO(12) observations also show that AFGL 2591 is embedded in a molecular cloud with an LSR velocity of -5 km/s.

  14. High Resolution Observations of Magnetic Elements in the Visible and the Infrared

    NASA Astrophysics Data System (ADS)

    Rimmele, T.; Lin, H.

    1997-05-01

    High resolution observations of magnetic elements in the visible and infrared. We report on multi-wavelength observations of plage regions obtained at the Vacuum Tower Telescope at NSO/Sac-Peak . The data set includes high resolution images in the G-band (0.43 mu ), the visible (0.69 mu ) continuum and the infrared (1.6 mu ) continuum. In addition, deep integration full Stokes vector measurements in the FeI 1.56 mu lines, as well as, Ca-K slit jaw images were obtained. G-band bright points, which are observed mostly in supergranular lanes, are also visible as bright points in the visible continuum. Although the infrared observations are limited in spatial resolution to about 0."4 (the diffraction limit of the VTT/SP), the data indicates that G-band bright points are also bright in the infrared (1.6 mu ). We also discuss and compare properties of magnetic knots and small pores. Magnetic knots, which recently also have been referred to as azimuth centers (Lites et al. 1994), by definition show no darkening in individual continuum images. However, in the time-averaged imaging data, and in particular in the infrared, azimuth centers appear as dark features, which are clearly distinguishable from the quiet sun background. In the infrared most azimuth centers are visible as dark features even in individual snapshots. Many azimuth centers as well as some small pores are surrounded by a highly structured bright ring, which becomes more apparent with increasing height of formation. Results of the polarization analysis in the FeI 1.56 mu lines, including measurements of weak fields, are presented as well.

  15. Comparison of dynamical model atmospheres of Mira variables with mid-infrared interferometric and spectroscopic observations

    NASA Astrophysics Data System (ADS)

    Ohnaka, K.; Scholz, M.; Wood, P. R.

    2006-02-01

    We present a comparison of dynamical model atmospheres with mid-infrared (~11 μm) interferometric and spectroscopic observations of the Mira variable o Cet. The dynamical model atmospheres of Mira variables pulsating in the fundamental mode can fairly explain, without assuming ad-hoc components, the seemingly contradictory mid-infrared spectroscopic and interferometric observations of o Cet: the 11 μm sizes measured in the bandpass without any salient spectral features are about twice as large as those measured in the near-infrared. Our calculations of synthetic spectra show that the strong absorption due to a number of optically thick H2O lines is filled in by the emission of these H2O lines originating in the geometrically extended layers, providing a possible physical explanation for the picture proposed by Ohnaka (2004a) based on a semi-empirical modeling. This filling-in effect results in rather featureless, continuum-like spectra in rough agreement with the observed high-resolution 11 μm spectra, although the models still predict the H2O lines to be more pronounced than the observations. The inverse P-Cyg profiles of some strong H2O lines observed in the 11 μm spectra can also be reasonably reproduced by our dynamical model atmospheres. The presence of the extended H2O layers manifests itself as mid-infrared angular diameters much larger than the continuum diameter. The 11 μm uniform-disk diameters predicted by our dynamical model atmospheres are in fair agreement with those observed with the Infrared Spatial Interferometer (ISI), but still somewhat smaller than the observed diameters. We discuss possible reasons for this discrepancy and problems with the current dynamical model atmospheres of Mira variables.

  16. Luminous Infrared Galaxies Observed from the Ground and Space in the 2020s

    NASA Astrophysics Data System (ADS)

    Inami, Hanae; Armus, L.; Packham, C.; Dickinson, M.

    2014-07-01

    The dust-penetrating power of infrared observations will allow us to reveal the physical and chemical properties in and around the dust enshrouded nuclei of galaxies. While current near-infrared spectroscopic observations with 8-10m class telescopes can access to z=1-3 regime, they are still very challenging and limited to luminous targets. For z=0 objects, these telescopes can resolve HII regions, but we still do not fully understand the properties of more extreme star formation environments (e.g., rich in gas), which are more prevalent at higher redshifts. Near- and mid-infrared TMT instruments (e.g., two of the first light instruments IRIS and IRMS, and a planned mid-infrared instrument MICHI) will exploit TMT's unprecedented high spatial resolution to constrain the physical processes in individual dusty, intense star-forming regions of local galaxies as well as obtain resolved spectra for z=2-3 star-forming galaxies. During the era of 2020, JWST and SPICA are also expected to be commissioned. The high sensitivity of these space-based infrared observatories will facilitate investigations of the properties of dusty galaxies at even higher redshifts (z > 3). Only with the combination of ground- and space-observatories, we will be able to obtain a complete picture of star formation and AGN activity to explore the evolution of LIRGs which dominate the peak of the galaxy growth in the universe.

  17. Near- and far-infrared observations of interplanetary dust bands from the COBE diffuse infrared background experiment

    NASA Technical Reports Server (NTRS)

    Spiesman, William J.; Hauser, Michael G.; Kelsall, Thomas; Lisse, Carey M.; Moseley, S. Harvey, Jr.; Reach, William T.; Silverberg, Robert F.; Stemwedel, Sally W.; Weiland, Janet L.

    1995-01-01

    Data from the Diffuse Infrared Background Experiment (DIRBE) instrument aboard the Cosmic Background Explorer Satellite (COBE) spacecraft have been used to examine the near and far infrared signatures of the interplanetary dust (IPD) bands. Images of the dust band pairs at ecliptic latitudes of +/- 1.4 deg and +/- 10 deg have been produced at DIRBE wavelengths from 1.25 to 100 micrometers. The observations at the shorter wavelengths provide the first evidence of scattered sunlight from particles responsible for the dust bands. It is found that the grains in the bands and those in the smooth IPD cloud have similar spectral energy distributions, suggesting similar compositions and possibly a common origin. The scattering albedos from 1.25 to 3.5 micrometers for the grains in the dust bands and those in the IPD cloud are 0.22 and 0.29, respectively. The 10 deg band pair is cooler (185 +/- 10 K) than the smooth interplanetary dust cloud (259 +/- 10 K). From both parallactic and thermal analyses, the implied location of the grains responsible for the peak brightness of the 10 deg band pair is 2.1 +/- 0.1 AU the Sun A parallactic distance of 1.4 +/- 0.2 AU is found for the peak of the 1.4 deg band pair.

  18. Near- and far-infrared observations of interplanetary dust bands from the COBE diffuse infrared background experiment

    NASA Technical Reports Server (NTRS)

    Spiesman, William J.; Hauser, Michael G.; Kelsall, Thomas; Lisse, Carey M.; Moseley, S. Harvey, Jr.; Reach, William T.; Silverberg, Robert F.; Stemwedel, Sally W.; Weiland, Janet L.

    1995-01-01

    Data from the Diffuse Infrared Background Experiment (DIRBE) instrument aboard the Cosmic Background Explorer Satellite (COBE) spacecraft have been used to examine the near and far infrared signatures of the interplanetary dust (IPD) bands. Images of the dust band pairs at ecliptic latitudes of +/- 1.4 deg and +/- 10 deg have been produced at DIRBE wavelengths from 1.25 to 100 micrometers. The observations at the shorter wavelengths provide the first evidence of scattered sunlight from particles responsible for the dust bands. It is found that the grains in the bands and those in the smooth IPD cloud have similar spectral energy distributions, suggesting similar compositions and possibly a common origin. The scattering albedos from 1.25 to 3.5 micrometers for the grains in the dust bands and those in the IPD cloud are 0.22 and 0.29, respectively. The 10 deg band pair is cooler (185 +/- 10 K) than the smooth interplanetary dust cloud (259 +/- 10 K). From both parallactic and thermal analyses, the implied location of the grains responsible for the peak brightness of the 10 deg band pair is 2.1 +/- 0.1 AU the Sun A parallactic distance of 1.4 +/- 0.2 AU is found for the peak of the 1.4 deg band pair.

  19. Amplitude of the diurnal temperature cycle as observed by thermal infrared and microwave radiometers

    USDA-ARS?s Scientific Manuscript database

    Land surface temperature (LST) is a key input to physically-based retrieval algorithms of hydrological states and fluxes, and global measurements of LST are provided by many satellite platforms. Passive microwave (MW) observations offer an alternative to conventional thermal infrared (TIR) LST retri...

  20. Statistical retrieval of thin liquid cloud microphysical properties using ground-based infrared and microwave observations

    NASA Astrophysics Data System (ADS)

    Marke, Tobias; Ebell, Kerstin; Löhnert, Ulrich; Turner, David D.

    2016-12-01

    In this article, liquid water cloud microphysical properties are retrieved by a combination of microwave and infrared ground-based observations. Clouds containing liquid water are frequently occurring in most climate regimes and play a significant role in terms of interaction with radiation. Small perturbations in the amount of liquid water contained in the cloud can cause large variations in the radiative fluxes. This effect is enhanced for thin clouds (liquid water path, LWP <100 g/m2), which makes accurate retrieval information of the cloud properties crucial. Due to large relative errors in retrieving low LWP values from observations in the microwave domain and a high sensitivity for infrared methods when the LWP is low, a synergistic retrieval based on a neural network approach is built to estimate both LWP and cloud effective radius (reff). These statistical retrievals can be applied without high computational demand but imply constraints like prior information on cloud phase and cloud layering. The neural network retrievals are able to retrieve LWP and reff for thin clouds with a mean relative error of 9% and 17%, respectively. This is demonstrated using synthetic observations of a microwave radiometer (MWR) and a spectrally highly resolved infrared interferometer. The accuracy and robustness of the synergistic retrievals is confirmed by a low bias in a radiative closure study for the downwelling shortwave flux, even for marginally invalid scenes. Also, broadband infrared radiance observations, in combination with the MWR, have the potential to retrieve LWP with a higher accuracy than a MWR-only retrieval.

  1. Observations of Leonid Meteors Using a Mid-Wave Infrared Imaging Spectrograph

    NASA Technical Reports Server (NTRS)

    Rossano, G. S.; Russell, R. W.; Lynch, D. K.; Tessensohn, T. K.; Warren, D.; Jenniskens, P.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    We report broadband 3-5.5 micrometer detections of two Leonid meteors observed during the 1998 Leonid Multi-Instrument Aircraft Campaign. Each meteor was detected at only one position along their trajectory just prior to the point of maximum light emission. We describe the particular aspects of the Aerospace Corp. Mid-wave Infra-Red Imaging Spectrograph (MIRIS) developed for the observation of short duration transient events that impact its ability to detect Leonid meteors. This instrument had its first deployment during the 1998 Leonid MAC. We infer from our observations that the mid-infrared light curves of two Leonid meteors differed from the visible light curve. At the points of detection, the infrared emission in the MIRIS passband was 25 +/- 4 times that at optical wavelengths for both meteors. In addition, we find an upper limit of 800 K for the solid body temperature of the brighter meteor we observed, at the point in the trajectory where we made our mid-wave infrared detection.

  2. Infrared observations of Io during the mutual events of 1985 - Evidence of volcanic activity?

    NASA Astrophysics Data System (ADS)

    Medina, F.; Echevarria, J.; Ledezma, E.; Martinez, F.

    1989-08-01

    Infrared photometry for a 40 percent occultation of Io by Ganymede and a total occultation by Callisto is reported. Anomalous flux variations observed are interpreted as occultations of active hot spots on Io. Possible identification of these spots with well-known features are discussed.

  3. NASA Satellite Observes Iceland Eyjafjallajökull Volcano in Infrared

    NASA Image and Video Library

    2010-04-21

    The Advanced Land Imager onboard NASA Earth Observing-1 EO-1 spacecraft obtained this false-color infrared image of Iceland Eyjafjallajökull volcano on April 17, 2010. A strong thermal source is visible at the base of the Eyjafjallajökull plume.

  4. United Kingdom Infrared Telescope's Spectrograph Observations of Human-Made Space Objects

    NASA Technical Reports Server (NTRS)

    Buckalew, Brent; Abercromby, Kira; Lederer, Susan; Frith, James; Cowardin, Heather

    2017-01-01

    Presented here are the results of the United Kingdom Infrared Telescope (UKIRT) spectral observations of human-made space objects taken from 2014 to 2015. The data collected using the UIST infrared spectrograph cover the wavelength range 0.7-2.5 micrometers. Overall, data were collected on 18 different orbiting objects at or near the geosynchronous (GEO) regime. Thirteen of the objects are spacecraft, one is a rocket body, and four are cataloged as debris pieces. The remotely collected data are compared to the laboratory-collected reflectance data on typical spacecraft materials; thereby general materials are identified but not specific types. These results highlight the usefulness of observations in the infrared by focusing on features from hydrocarbons and silicon. The spacecraft show distinct features due to the presence of solar panels. Signature variations between rocket bodies, due to the presence of various metals and paints on their surfaces, show a clear distinction from those objects with solar panels, demonstrating that one can distinguish most spacecraft from rocket bodies through infrared spectrum analysis. Finally, the debris pieces tend to show featureless, dark spectra. These results show that the laboratory data in its current state give excellent indications as to the nature of the surface materials on the objects. Further telescopic data collection and model updates to include more materials, noise, surface roughness, and material degradation are necessary to make better assessments of orbital object material types. A comparison conducted between objects observed previously with the NASA Infrared Telescope Facility (IRTF) shows similar materials and trends from the two telescopes and from the two distinct data sets. However, based on the current state of the model, infrared spectroscopic data are adequate to classify objects in GEO as spacecraft, rocket bodies, or debris.

  5. Infrared Observations of Nova Sagittarii 2012 = Pnv J17452791-2305213

    NASA Astrophysics Data System (ADS)

    Raj, Ashish; Ashok, N. M.; Banerjee, D. P. K.; Venkata Raman, V.

    2012-05-01

    Ashish Raj, N. M. Ashok, D. P. K. Banerjee and V. Venkata Raman, Physical Research Laboratory, report near-infrared J-, H-, and K-band photometry of the Nova Sgr 2012 (cf. CBET 3089) obtained with the Mt. Abu 1.2-m telescope (+PRL Near-Infrared NICMOS3 Imager/Spectrometer). The preliminary reduction of these Mt. Abu observations of 2012 April 29.978 UT and May 1.896 UT shows the declining trend in the brightness of the nova in the JHK bands.

  6. InSAR Observations and Finite Element Modeling of Crustal Deformation Around a Surging Glacier, Iceland

    NASA Astrophysics Data System (ADS)

    Spaans, K.; Auriac, A.; Sigmundsson, F.; Hooper, A. J.; Bjornsson, H.; Pálsson, F.; Pinel, V.; Feigl, K. L.

    2014-12-01

    Icelandic ice caps, covering ~11% of the country, are known to be surging glaciers. Such process implies an important local crustal subsidence due to the large ice mass being transported to the ice edge during the surge in a few months only. In 1993-1995, a glacial surge occurred at four neighboring outlet glaciers in the southwestern part of Vatnajökull ice cap, the largest ice cap in Iceland. We estimated that ~16±1 km3 of ice have been moved during this event while the fronts of some of the outlet glaciers advanced by ~1 km.Surface deformation associated with this surge has been surveyed using Interferometric Synthetic Aperture Radar (InSAR) acquisitions from 1992-2002, providing high resolution ground observations of the study area. The data show about 75 mm subsidence at the ice edge of the outlet glaciers following the transport of the large volume of ice during the surge (Fig. 1). The long time span covered by the InSAR images enabled us to remove ~12 mm/yr of uplift occurring in this area due to glacial isostatic adjustment from the retreat of Vatnajökull ice cap since the end of the Little Ice Age in Iceland. We then used finite element modeling to investigate the elastic Earth response to the surge, as well as confirm that no significant viscoelastic deformation occurred as a consequence of the surge. A statistical approach based on Bayes' rule was used to compare the models to the observations and obtain an estimate of the Young's modulus (E) and Poisson's ratio (v) in Iceland. The best-fitting models are those using a one-kilometer thick top layer with v=0.17 and E between 12.9-15.3 GPa underlain by a layer with v=0.25 and E from 67.3 to 81.9 GPa. Results demonstrate that InSAR data and finite element models can be used successfully to reproduce crustal deformation induced by ice mass variations at Icelandic ice caps.Fig. 1: Interferograms spanning 1993 July 31 to 1995 June 19, showing the surge at Tungnaárjökull (Tu.), Skaftárjökull (Sk.) and S

  7. DISTRIBUTION OF CO{sub 2} IN SATURN'S ATMOSPHERE FROM CASSINI/CIRS INFRARED OBSERVATIONS

    SciTech Connect

    Abbas, M. M.; LeClair, A.; Woodard, E.; Young, M.; Stanbro, M.; Flasar, F. M.; Achterberg, R. K.; Bjoraker, G.; Brasunas, J.; Jennings, D. E.; Kunde, V. G. E-mail: Andre.C.LeClair@nasa.gov E-mail: mcs0001@uah.edu E-mail: f.m.flasar@nasa.gov; Collaboration: and the Cassini /CIRS team

    2013-10-20

    This paper focuses on the CO{sub 2} distribution in Saturn's atmosphere based on analysis of infrared spectral observations of Saturn made by the Composite Infrared Spectrometer aboard the Cassini spacecraft. The Cassini spacecraft was launched in 1997 October, inserted in Saturn's orbit in 2004 July, and has been successfully making infrared observations of Saturn, its rings, Titan, and other icy satellites during well-planned orbital tours. The infrared observations, made with a dual Fourier transform spectrometer in both nadir- and limb-viewing modes, cover spectral regions of 10-1400 cm{sup –1}, with the option of variable apodized spectral resolutions from 0.53 to 15 cm{sup –1}. An analysis of the observed spectra with well-developed radiative transfer models and spectral inversion techniques has the potential to provide knowledge of Saturn's thermal structure and composition with global distributions of a series of gases. In this paper, we present an analysis of a large observational data set for retrieval of Saturn's CO{sub 2} distribution utilizing spectral features of CO{sub 2} in the Q-branch of the ν{sub 2} band, and discuss its possible relationship to the influx of interstellar dust grains. With limited spectral regions available for analysis, due to low densities of CO{sub 2} and interference from other gases, the retrieved CO{sub 2} profile is obtained as a function of a model photochemical profile, with the retrieved values at atmospheric pressures in the region of ∼1-10 mbar levels. The retrieved CO{sub 2} profile is found to be in good agreement with the model profile based on Infrared Space Observatory measurements with mixing ratios of ∼4.9 × 10{sup –10} at atmospheric pressures of ∼1 mbar.

  8. Distribution of CO2 in Saturn's Atmosphere from Cassini/cirs Infrared Observations

    NASA Astrophysics Data System (ADS)

    Abbas, M. M.; LeClair, A.; Woodard, E.; Young, M.; Stanbro, M.; Flasar, F. M.; Kunde, V. G.; Achterberg, R. K.; Bjoraker, G.; Brasunas, J.; Jennings, D. E.; the Cassini/CIRS Team

    2013-10-01

    This paper focuses on the CO2 distribution in Saturn's atmosphere based on analysis of infrared spectral observations of Saturn made by the Composite Infrared Spectrometer aboard the Cassini spacecraft. The Cassini spacecraft was launched in 1997 October, inserted in Saturn's orbit in 2004 July, and has been successfully making infrared observations of Saturn, its rings, Titan, and other icy satellites during well-planned orbital tours. The infrared observations, made with a dual Fourier transform spectrometer in both nadir- and limb-viewing modes, cover spectral regions of 10-1400 cm-1, with the option of variable apodized spectral resolutions from 0.53 to 15 cm-1. An analysis of the observed spectra with well-developed radiative transfer models and spectral inversion techniques has the potential to provide knowledge of Saturn's thermal structure and composition with global distributions of a series of gases. In this paper, we present an analysis of a large observational data set for retrieval of Saturn's CO2 distribution utilizing spectral features of CO2 in the Q-branch of the ν2 band, and discuss its possible relationship to the influx of interstellar dust grains. With limited spectral regions available for analysis, due to low densities of CO2 and interference from other gases, the retrieved CO2 profile is obtained as a function of a model photochemical profile, with the retrieved values at atmospheric pressures in the region of ~1-10 mbar levels. The retrieved CO2 profile is found to be in good agreement with the model profile based on Infrared Space Observatory measurements with mixing ratios of ~4.9 × 10-10 at atmospheric pressures of ~1 mbar.

  9. 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.

  10. Far-infrared and submillimeter-wavelength observations of star-forming dense cores. I. Spectra

    SciTech Connect

    Ladd, E.F.; Adams, F.C.; Fuller, G.A.; Casey, S.; Davidson, J.A. Yerkes Observatory, Williams Bay, WI NASA, Ames Research Center, Moffett Field, CA )

    1991-01-01

    Far-infrared and submillimeter photometry of 10 low-mass star formation regions containing embedded IRAS sources is presented. These new observations define the peak of the spectral energy distributions of these objects and provide more precise estimates of their bolometric luminosities. Two new sources, L1527 and L483, are among the reddest known low-mass objects, with spectral energy distribution peaks at 100-200 microns and extremely steep IRAS slopes. These cold sources have spectra which are similar to blackbodies of 30-40 K but have significant excess emission on the Wien side. Models of the spectral energy distributions using a spherically symmetric core structure indicate that these sources have visual extinctions greater than 1000 mag. However, models with these large extinctions predict too little near-infrared emission. A nonspherically symmetric distribution of circumstellar material may play a role in the generation of the extra near-infrared emission. 64 refs.

  11. Spectral and Imaging Observations of a White-light Solar Flare in the Mid-infrared

    NASA Astrophysics Data System (ADS)

    Penn, Matt; Krucker, Säm; Hudson, Hugh; Jhabvala, Murzy; Jennings, Don; Lunsford, Allen; Kaufmann, Pierre

    2016-03-01

    We report high-resolution observations at mid-infrared wavelengths of a minor solar flare, SOL2014-09-24T17:50 (C7.0), using Quantum Well Infrared Photodetector cameras at an auxiliary of the McMath-Pierce telescope. The flare emissions, the first simultaneous observations in two mid-infrared bands at 5.2 and 8.2 μ {{m}} with white-light and hard X-ray coverage, revealed impulsive time variability with increases on timescales of ˜4 s followed by exponential decay at ˜10 s in two bright regions separated by about 13\\prime\\prime . The brightest source is compact, unresolved spatially at the diffraction limit (1\\_\\_AMP\\_\\_farcs;72 at 5.2 μ {{m}}). We identify the IR sources as flare ribbons also seen in white-light emission at 6173 Å observed by SDO/HMI, with twin hard X-ray sources observed by Reuven Ramaty High Energy Solar Spectroscopic Imager, and with EUV sources (e.g., 94 Å) observed by SDO/AIA. The two infrared points have nearly the same flux density (fν, W m-2 Hz) and extrapolate to a level of about an order of magnitude below that observed in the visible band by HMI, but with a flux of more than two orders of magnitude above the free-free continuum from the hot (˜15 MK) coronal flare loop observed in the X-ray range. The observations suggest that the IR emission is optically thin; this constraint and others suggest major contributions from a density less than about 4× {10}13 cm-3. We tentatively interpret this emission mechanism as predominantly free-free emission in a highly ionized but cool and rather dense chromospheric region.

  12. Infrared

    NASA Astrophysics Data System (ADS)

    Vollmer, M.

    2013-11-01

    'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the

  13. Comparing the diameters and visual albedos derived from radar and infrared observations

    NASA Astrophysics Data System (ADS)

    Taylor, P.; Howell, E.; Nolan, M.; Springmann, A.; Vervack, R., Jr.; Fernandez, Y.; Magri, C.

    2014-07-01

    Radar observations provide direct measurements of the physical sizes of near-Earth objects, independent of visual albedo, composition, and thermal properties, which can act as calibration or sanity checks for models of thermal-infrared emission by small bodies. Thermal modeling of infrared observations by the NEOWISE [1--3] and ExploreNEOs (Spitzer) [4--6] programs has provided diameters and visual albedos for several hundred near-Earth objects. Meanwhile, since 1998, the Arecibo radar program has detected over 350 near-Earth objects, including more than 40 objects from each of the NEOWISE and ExploreNEOs catalogs, providing rotation-rate, size, and shape constraints depending on the strength and resolution of the received echoes. In addition, our observations with the SpeX instrument on the NASA IRTF provide a sample of roughly two dozen objects, observed on multiple dates at different viewing geometries, that were also observed by the Arecibo radar and NEOWISE and/or ExploreNEOs programs. We will compare the diameters and visual albedos inferred from radar to those derived from thermal modeling of infrared observations from WISE, Spitzer, and/or the IRTF, and look for correlations between the outliers and their sizes, shapes, compositions, and viewing geometries, all of which can affect the assumptions made in the process of standard thermal modeling.

  14. Experimental observations and finite element analysis of the initiation of fiber microbuckling in notched composite laminates

    NASA Technical Reports Server (NTRS)

    Guynn, E. Gail; Bradley, Walter L.

    1989-01-01

    An understanding was developed of the factors that determine the semi-circular edge-notched compressive strength and the associated failure mode(s) were identified of thermoplastic composite laminates with multidirectional stacking sequences. The experimental observations and the detailed literature review suggest at least four factors that affected the determination of the strain levels at which fiber microbuckling initiates and thus, partially control the composite's compression strength. The dependent variables studied are the compressive strength of a reduced gage section compression specimen and the compression strength of a compression specimen with two semi-circular edge notches (no opposite free edges) centered along the gage section. In this research, specimens containing two semi-circular edge notches (no opposite free edges) were loaded in compression at a relatively slow rate to provide more stable development of fiber microbuckling damage. The results indicate that the local constraints (free surfaces, supporting ply orientation, and resin-rich regions) significantly affect the strain level for the initiation of in-plane fiber microbuckling. Preliminary results at an elevated temperature, 77 C, showed the shear stress yield strength of the resin was reduced and consequently, the resistance to fiber microbuckling was also reduced. The finite element analysis of the perfectly straight fiber problem indicates that the free surface effect causes a 10 percent reduction in the critical buckling strain. However, the experimentally measured reduction for fibers with an initial fiber curvature, was 35 percent.

  15. Patterns of tectonic stress in Sicily from borehole breakout observations and finite element modeling

    NASA Astrophysics Data System (ADS)

    Ragg, Steffen; Grasso, Mario; Müller, Birgit

    1999-08-01

    The orientation of in situ tectonic stress was deduced from borehole breakout analysis of 22 wells from onshore Sicily. The results allow us to distinguish the stress field of different geological units: (1) A nearly NNW (148°) orientation is detected in the Hyblean Plateau. (2) A NNE SHmax direction characterizes the Gela area. To the north, within the thrust belt (around Mount Judica), the SHmax direction swings to NE. In the northeastern segment of the foredeep, the Catania Plain, the direction of SHmax is roughly parallel to the NE trending grabens that mark the northern margin of the Hyblean Plateau. (3) The southwestern segment of the foredeep has no preferential SHmax orientation and may act as a transition zone with isotropic horizontal stresses. (4) In western Sicily a SHmax orientation from N-S to NW-SE is observed. This fits well the kinematics of the SE migrating Egadi and Adventure thrust belts and the direction of shortening inferred from the modern seismicity of the area. A three-dimensional finite element modeling, including the most important tectonic features, was performed. Modeling results of the stress field indicate that the NNW trending SHmax is locally influenced by the variation of crustal thickness and local zones of weakness. In addition, the Pantelleria Rift causes a rotation of the regional NW-SE stress orientation to NNE along the northern rim of the rift system, including large on-shore areas in the adjacent central south Sicily.

  16. Infrared observations of Jovian aurora from Juno's first orbits: Main oval and satellite footprints

    NASA Astrophysics Data System (ADS)

    Mura, A.; Adriani, A.; Altieri, F.; Connerney, J. E. P.; Bolton, S. J.; Moriconi, M. L.; Gérard, J.-C.; Kurth, W. S.; Dinelli, B. M.; Fabiano, F.; Tosi, F.; Atreya, S. K.; Bagenal, F.; Gladstone, G. R.; Hansen, C.; Levin, S. M.; Mauk, B. H.; McComas, D. J.; Sindoni, G.; Filacchione, G.; Migliorini, A.; Grassi, D.; Piccioni, G.; Noschese, R.; Cicchetti, A.; Turrini, D.; Stefani, S.; Amoroso, M.; Olivieri, A.

    2017-06-01

    The Jovian Infrared Auroral Mapper (JIRAM) is an imager/spectrometer on board NASA/Juno mission for the study of the Jovian aurorae. The first results of JIRAM's imager channel observations of the H3+ infrared emission, collected around the first Juno perijove, provide excellent spatial and temporal distribution of the Jovian aurorae, and show the morphology of the main ovals, the polar regions, and the footprints of Io, Europa and Ganymede. The extended Io "tail" persists for 3 h after the passage of the satellite flux tube. Multi-arc structures of varied spatial extent appear in both main auroral ovals. Inside the main ovals, intense, localized emissions are observed. In the southern aurora, an evident circular region of strong depletion of H3+ emissions is partially surrounded by an intense emission arc. The southern aurora is brighter than the north one in these observations. Similar, probably conjugate emission patterns are distinguishable in both polar regions.

  17. Optical and near infrared observations of the blazar 3C 279 with the REM telescope.

    NASA Astrophysics Data System (ADS)

    Impiombato, D.; Tosti, G.; Ciprini, C.; REM Collaboration.

    The Rapid Eye Mount (REM) telescope installed at La Silla (Cile) on June 2003, is a robotic telescope able the capability to observe in optical and infrared bands. Since the late commissioning phase a optical and infrared monitoring program of a sample of blazars, most emitting also in the gamma-ray band, was started. Such program is still on going and it make part of an observational activity aimed to the multiwavelength characterization possible blazars candidate to be observed also in gamma-ray by the instruments on board of AGILE satellites(launched on 23 April 2007) and Glast (that will be launched at the end of the 2007). In this poster we present the optical/near-IR data obtained during the January 2007, outburst of 3C279 (the prototype of the gamma-ray loud).

  18. Observation of head-shaking nystagmus with an infrared Frenzel's glass.

    PubMed

    Yuen, K; Fujimoto, M; Masuda, Y

    1995-01-01

    It has been reported that a head-shaking test is very useful in clinical practice. To observe head-shaking nystagmus (HSN) a Frenzel's glass and electronystagmography (ENG) have been used. Although observation with Frenzel's glass is a simple method, it tends to suppress after shaking nystagmus, as gazing is not completely eliminated with Frenzel's glass. An electronystagmogram in darkness can eliminate gazing completely, but it requires much trouble in routine use. We therefore tried to use Frenzel's glass with an infrared CCD camera. We observed highly provoked HSN like ENG in darkness and were able to use it without difficulty. We recognized the second phase in several cases with only an infrared Frenzel's glass and the rotatory component of the nystagmus. This method is more convenient and valuable for clinical use than ENG and Frenzel's glass.

  19. Validation of Carbon Monoxide and Methane Vertical Column Densities Retrieved from SCIAMACHY Infrared Nadir Observations

    NASA Astrophysics Data System (ADS)

    Hochstaffl, Philipp; Hamidouche, Mourad; Schreier, Franz; Gimeno Garcia, Sebastian; Lichtenberg, Günter

    2016-04-01

    Carbon monoxide and methane are key species of Earth's atmosphere, highly relevant for climate and air quality. Accordingly, a large number of spaceborne sensors are observing these species in the microwave, thermal and near infrared. For the analysis of short wave infrared spectra measured by SCIAMACHY aboard the ENVISAT satellite and similar instrument(s) we had developed the Beer InfraRed Retrieval Algorithm: BIRRA is a separable least squares fit of the measured radiance with respect to molecular column densities and auxiliary parameters (optional: surface albedo, baseline, slit function width, and wavenumber shift). BIRRA has been implemented in the operational SCIAMACHY L1 to 2 processor for the retrieval of CO and CH4 from channel 8 (2.3 mue) and 6 (1.6 mue), respectively. Our tests are based on separate comparisons with existing space or ground-based measurements of carbon monoxide and methane column densities. In this poster intercomparisons of CO and CH4 columns estimated from SCIAMACHY with coincident and co-located retrievals provided by ground-based Fourier transform infrared spectroscopy are provided. More specifically, we have used data from several NDACC (Network for the Detection of Atmospheric Composition Change) and TCCON (Total Carbon Column Observing Network) stations. Our strategy for quality check of these products and the selection of specific geographical areas will be discussed.

  20. Exploration of the Saturn System by the Cassini Mission: Observations with the Cassini Infrared Spectrometer

    NASA Technical Reports Server (NTRS)

    Abbas, Mian M.

    2014-01-01

    The Cassini mission is a joint NASA-ESA international mission, launched on October 17, 1997 with 12 instruments on board, for exploration of the Saturn system. A composite Infrared Spectrometers is one of the major instruments. Successful insertion of the spacecraft in Saturn's orbit for an extended orbital tour occurred on July 1, 2004. The French Huygens-Probe on board, with six instruments was programmed for a soft landing on Titan's surface occurred in January 2005. The broad range scientific objectives of the mission are: Exploration of the Saturn system for investigations of the origin, formation, & evolution of the solar system, with an extensive range of measurements and the analysis of the data for scientific interpretations. The focus of research dealing with the Cassini mission at NASA/MSFC in collaboration with the NASA/Goddard Space Flight Center, JPL, as well as the research teams at Oxford/UK and Meudon Observatory/France, involves the Infrared observations of Saturn and its satellites, for measurements of the thermal structure and global distributions of the atmospheric constituents. A brief description of the Cassini spacecraft, the instruments, the objectives, in particular with the infrared observations of the Saturn system will be given. The analytical techniques for infrared radiative transfer and spectral inversion programs, with some selected results for gas constituent distributions will be presented.

  1. A Compact Infrared Space Telescope MIRIS and its Preliminary Observational Results

    NASA Astrophysics Data System (ADS)

    Han, Wonyong; Pyo, Jeonghyun; Kim, Il-Joong; Lee, Dae-Hee; Jeong, Woong-Seob; Moon, Bongkon; Park, Youngsik; Park, Sung-Joon; Lee, Dukhang; Park, Won-Kee; Ko, Kyeongyeon; Kim, Min Gyu; Nam, Uk-Won; Park, Hong-Young; Lee, Hyung Mok; Matsumoto, Toshio

    2015-08-01

    The first Korean infrared space telescope MIRIS (Milti-purpose InfraRed Imaging System) was successfully launched in November 2013, as the main payload of Korean STSAT-3 (Science and Technology Satellite-3). After the initial on-orbit operation for verification, the observations are made with MIRIS for the fluctuation of Cosmic Infrared Background (CIB) and the Galactic Plane survey. For the study of near-infrared background, MIRIS surveyed large areas (> 10° x 10°) around the pole regions: the north ecliptic pole (NEP), the north and south Galactic poles (NGP, SGP), while the NEP region is continually monitored for the instrumental calibration and the zodiacal light study. In addition, the Paschen-α Galactic plane survey has been made with two narrow-band filters (at 1.88 μm and 1.84+1.92 μm) for the study of warm interstellar medium. We plan to continue surveying the entire galactic plane with the latitude of ±3°, and expect to be completed by 2015. The data are still under the stage of reduction and analysis, and guest observations are on-going. We present some of the preliminary results.

  2. AKARI OBSERVATION OF THE SUB-DEGREE SCALE FLUCTUATION OF THE NEAR-INFRARED BACKGROUND

    SciTech Connect

    Seo, H. J.; Lee, Hyung Mok; Lee, Myung Gyoon; Matsumoto, T.; Jeong, W.-S.; Pyo, J.

    2015-07-10

    We report spatial fluctuation analysis of the sky brightness in the near-infrared from observations toward the north ecliptic pole (NEP) by the AKARI at 2.4 and 3.2 μm. As a follow-up study of our previous work on the Monitor field of AKARI, we used NEP deep survey data, which covered a circular area of about 0.4 square degrees, in order to extend fluctuation analysis at angular scales up to 1000″. We found residual fluctuation over the estimated shot noise at larger angles than the angular scale of the Monitor field. The excess fluctuation of the NEP deep field smoothly connects with that of the Monitor field at angular scales of a few hundred arcseconds and extends without any significant variation to larger angular scales up to 1000″. By comparing excess fluctuations at two wavelengths, we confirm a blue spectral feature similar to the result of the Monitor field. We find that the result of this study is consistent with Spitzer Space Telescope observations at 3.6 μm. The origin of the excess fluctuation in the near-infrared background remains to be determined, but we could exclude zodiacal light, diffuse Galactic light, and unresolved faint galaxies at low redshift based on the comparison with mid- and far-infrared brightness, ground-based near-infrared images.

  3. United Kingdom Infrared Telescope's Spectrograph Observations of Human-Made Space Objects

    NASA Technical Reports Server (NTRS)

    Buckalew, Brent; Abercromby, Kira; Lederer, Susan; Cowardin, Heather; Frith, James

    2017-01-01

    Presented here are the results of the United Kingdom Infrared Telescope (UKIRT) spectral observations of human-made space objects taken from 2014 to 2015. The data collected using the UKIRT 1-5 micron Imager Spectrometer (UIST) cover the wavelength range 0.7-2.5 micrometers. Overall, data were collected on 18 different orbiting objects at or near geosynchronous orbit (GEO). Two of the objects are controlled spacecraft, twelve are non-controlled spacecraft, one is a rocket body, and three are cataloged as debris. The remotely collected data are compared to the laboratory-collected reflectance data on typical spacecraft materials; thereby general materials are identified but not specific types. These results highlight the usefulness of observations in the infrared by focusing on features from hydrocarbons and silicon. The spacecraft, both the controlled and non-controlled, show distinct features due to the presence of solar panels whereas the rocket bodies do not. Signature variations between rocket bodies, due to the presence of various metals and paints on their surfaces, show a clear distinction from those objects with solar panels, demonstrating that one can distinguish most spacecraft from rocket bodies through infrared spectrum analysis. Finally, the debris pieces tend to show featureless, dark spectra. These results show that the laboratory data in its current state give well-correlated indications as to the nature of the surface materials on the objects. Further telescopic data collection and model updates to include noise, surface roughness, and material degradation are necessary to make better assessments of orbital object material types. A comparison conducted between objects observed previously with the NASA Infrared Telescope Facility (IRTF) shows similar materials and trends from the two telescopes and different times. However, based on the current state of the model, infrared spectroscopic data are adequate to classify objects in GEO as spacecraft

  4. Infrared Telescope Facility's Spectrograph Observations of Human-Made Space Objects

    NASA Technical Reports Server (NTRS)

    Abercromby, K.; Buckalew, B.; Abell, P.; Cowardin, H.

    2015-01-01

    Presented here are the results of the Infrared Telescope Facility (IRTF) spectral observations of human-made space objects taken from 2006 to 2008. The data collected using the SpeX infrared spectrograph cover the wavelength range 0.7-2.5 micrometers. Overall, data were collected on 20 different orbiting objects at or near the geosynchronous (GEO) regime. Four of the objects were controlled spacecraft, seven were non-controlled spacecraft, five were rocket bodies, and the final four were cataloged as debris pieces. The remotely collected data are compared to the laboratory-collected reflectance data on typical spacecraft materials, thereby general materials are identified but not specific types. These results highlight the usefulness of observations in the infrared by focusing on features from hydrocarbons, silicon, and thermal emission. The spacecraft, both the controlled and non-controlled, show distinct features due to the presence of solar panels, whereas the rocket bodies do not. Signature variations between rocket bodies, due to the presence of various metals and paints on their surfaces, show a clear distinction from those objects with solar panels, demonstrating that one can distinguish most spacecraft from rocket bodies through infrared spectrum analysis. Finally, the debris pieces tend to show featureless, dark spectra. These results show that the laboratory data in its current state give excellent indications as to the nature of the surface materials on the objects. Further telescopic data collection and model updates to include noise, surface roughness, and material degradation are necessary to make better assessments of orbital object material types. However, based on the current state of the comparison between the observations and the laboratory data, infrared spectroscopic data are adequate to classify objects in GEO as spacecraft, rocket bodies, or debris.

  5. ISO Mid-Infrared Observations of Giant HII Regions in M33

    NASA Technical Reports Server (NTRS)

    Skelton, B. P.; Waller, W. H.; Hodge, P. W.; Boulanger, F.; Cornett, R. H.; Fanelli, M. N.; Lequeux, J.; Stecher, T. P.; Viallefond, F.; Hui, Y.

    1999-01-01

    We present Infrared Space Observatory Camera (ISOCAM) Circular Variable Filter scans of three giant HII regions in M33. IC 133, NGC 595, and CC 93 span a wide range of metallicity, luminosity, nebular excitation, and infrared excess; three other emission regions (CC 43, CC 99, and a region to the northeast of the core of NGC 595) are luminous enough in the mid-infrared to be detected in the observed fields. ISOCAM CVF observations provide spatially resolved observations (5'') of 151 wavelengths between 5.1 and 16.5 microns with a spectral resolution R = 35 to 50. We observe atomic emission lines ([Ne II], [Ne III], and [S IV]), several "unidentified infrared bands" (UIBs; 6.2, 7.7, 8.6, 11.3, 12.0, and 12.7 microns), and in some cases a continuum which rises steeply at longer wavelengths. We conclude that the spectra of these three GHRs are well explained by combinations of ionized gas, PAHs, and very small grains in various proportions and with different spatial distributions. Comparisons between observed ratios of the various UIBs with model ratios indicate that the PAHs in all three of the GHRs are dehydrogenated and that the small PAHs have been destroyed in IC 133 but have survived in NGC 595 and CC 93. The [Ne III]/[Ne II] ratios observed in IC 133 and NGC 595 are consistent with their ages of 5 and 4.5 Myr, respectively; the deduced ionization parameter is higher in IC 133, consistent with its more compact region of emission.

  6. ISO Mid-Infrared Observations of Giant HII Regions in M33

    NASA Technical Reports Server (NTRS)

    Skelton, B. P.; Waller, W. H.; Hodge, P. W.; Boulanger, F.; Cornett, R. H.; Fanelli, M. N.; Lequeux, J.; Stecher, T. P.; Viallefond, F.; Hui, Y.

    1999-01-01

    We present Infrared Space Observatory Camera (ISOCAM) Circular Variable Filter scans of three giant HII regions in M33. IC 133, NGC 595, and CC 93 span a wide range of metallicity, luminosity, nebular excitation, and infrared excess; three other emission regions (CC 43, CC 99, and a region to the northeast of the core of NGC 595) are luminous enough in the mid-infrared to be detected in the observed fields. ISOCAM CVF observations provide spatially resolved observations (5'') of 151 wavelengths between 5.1 and 16.5 microns with a spectral resolution R = 35 to 50. We observe atomic emission lines ([Ne II], [Ne III], and [S IV]), several "unidentified infrared bands" (UIBs; 6.2, 7.7, 8.6, 11.3, 12.0, and 12.7 microns), and in some cases a continuum which rises steeply at longer wavelengths. We conclude that the spectra of these three GHRs are well explained by combinations of ionized gas, PAHs, and very small grains in various proportions and with different spatial distributions. Comparisons between observed ratios of the various UIBs with model ratios indicate that the PAHs in all three of the GHRs are dehydrogenated and that the small PAHs have been destroyed in IC 133 but have survived in NGC 595 and CC 93. The [Ne III]/[Ne II] ratios observed in IC 133 and NGC 595 are consistent with their ages of 5 and 4.5 Myr, respectively; the deduced ionization parameter is higher in IC 133, consistent with its more compact region of emission.

  7. 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.

  8. 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.

  9. 9500 Nights of Mid-Infrared Observations of SN 1987A: the birth of the remnant

    NASA Astrophysics Data System (ADS)

    Bouchet, Patrice; Danziger, John

    2014-01-01

    The one-in-a-life-time event Supernova SN 1987A, the brightest supernova seen since Kepler's in 1604, has given us a unique opportunity to study the mechanics of a supernova explosion and now to witness the birth of a supernova remnant. A violent encounter is underway between the fastest-moving debris and the circumstellar ring: shocks excite ``hotspots''. ATCA/ANTF, Gemini, VLT, HST, Spitzer, Chandra, and recently ALMA observations have been so far organized to help understanding the several emission mechanisms at work. In the mid-infrared SN 1987A has transformed from a SN with the bulk of its radiation from the ejecta to a SNR whose emission is dominated by the interaction of the blast wave with the surrounding interstellar medium, a process in which kinetic energy is converted into radiative energy. Currently this remnant emission is dominated by material in or near the inner equatorial ring (ER). We give here a brief history of our mid-infrared observations, and present our last data obtained with the SPITZER infrared satellite and the ESO VLT and Gemini telescopes: we show how together with Chandra observations, they contribute to the understanding of this fascinating object. We argue also that our imaging observations suggest that warm dust is still present in the ejecta, and we dispute the presence of huge amount of very cold dust in it, as it has been claimed on the basis of data obtained with the HERSCHELl satellite.

  10. Hurricane Katrina as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: click on image for larger AIRS microwave image

    At 1:30 a.m. local time this morning, the remnants of (now Tropical Depression) Katrina were centered on the Mississippi-Tennessee border. This microwave image from the Atmospheric Infrared Sounder instrument on NASA's Aqua spacecrat shows that the area of most intense precipitation was concentrated to the north of the center of activity.

    The infrared image shows how the storms look through an AIRS Infrared window channel. Window channels measure the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures are associated with high, cold cloud tops that make up the top of the hurricane. The infrared signal does not penetrate through clouds, so the purple color indicates the cool cloud tops of the storm. In cloud-free areas, the infrared signal is retrieved at the Earth's surface, revealing warmer temperatures. Cooler areas are pushing to purple and warmer areas are pushing to red.

    The microwave image (figure 1) reveals where the heaviest precipitation in the hurricane is taking place. The blue areas within the storm show the location of this heavy precipitation. Blue areas outside of the storm where there are moderate or no clouds are where the cold (in the microwave sense) sea surface shines through.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard

  11. Hurricane Katrina as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: click on image for larger AIRS microwave image

    At 1:30 a.m. local time this morning, the remnants of (now Tropical Depression) Katrina were centered on the Mississippi-Tennessee border. This microwave image from the Atmospheric Infrared Sounder instrument on NASA's Aqua spacecrat shows that the area of most intense precipitation was concentrated to the north of the center of activity.

    The infrared image shows how the storms look through an AIRS Infrared window channel. Window channels measure the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures are associated with high, cold cloud tops that make up the top of the hurricane. The infrared signal does not penetrate through clouds, so the purple color indicates the cool cloud tops of the storm. In cloud-free areas, the infrared signal is retrieved at the Earth's surface, revealing warmer temperatures. Cooler areas are pushing to purple and warmer areas are pushing to red.

    The microwave image (figure 1) reveals where the heaviest precipitation in the hurricane is taking place. The blue areas within the storm show the location of this heavy precipitation. Blue areas outside of the storm where there are moderate or no clouds are where the cold (in the microwave sense) sea surface shines through.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard

  12. A Tool for Planning Optimal MOS Observations with the JWST Near-Infrared Spectrometer

    NASA Astrophysics Data System (ADS)

    Karakla, D.; Pontoppidan, K.; Beck, T.; Gilbert, K.; Curtis, G.

    2016-10-01

    The James Webb Space Telescope Near-Infrared Spectrograph (NIRSpec) will offer a powerful multi-object spectroscopic capability enabled by the instrument's micro-shutter arrays (MSAs). With this mode, the NIRSpec instrument can observe more than 100 targets simultaneously. The NIRSpec team at the Space Telescope Science Institute (STScI) has been developing an MSA Planning Tool (MPT) to facilitate the complex observation planning process for a variety of observing strategies. The MPT is available as part of the Astronomers Proposal Tool (APT).

  13. 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.

  14. Observation of runaway electrons by infrared camera in J-TEXT

    SciTech Connect

    Tong, R. H.; Chen, Z. Y. Zhang, M.; Huang, D. W.; Yan, W.; Zhuang, G.

    2016-11-15

    When the energy of confined runaway electrons approaches several tens of MeV, the runaway electrons can emit synchrotron radiation in the range of infrared wavelength. An infrared camera working in the wavelength of 3-5 μm has been developed to study the runaway electrons in the Joint Texas Experimental Tokamak (J-TEXT). The camera is located in the equatorial plane looking tangentially into the direction of electron approach. The runaway electron beam inside the plasma has been observed at the flattop phase. With a fast acquisition of the camera, the behavior of runaway electron beam has been observed directly during the runaway current plateau following the massive gas injection triggered disruptions.

  15. Observing Resolved Stellar Populations with the JWST Near-Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Gilbert, K. M.; Beck, T. L.; Karakla, D. M.

    2016-10-01

    The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) will provide a multi-object spectroscopy (MOS) mode through the Micro-Shutter Array (MSA). Each MSA quadrant is a grid of contiguous shutters that can be configured to form slits on more than 100 astronomical targets simultaneously. The combination of JWST's sensitivity and superb resolution in the infrared and NIRSpec's full wavelength coverage over 0.6 to 5 μm will open new parameter space for studies of galaxies and resolved stellar populations alike. We describe a NIRSpec MSA observing scenario of spectroscopy of individual stars in an external galaxy, and investigate the technical challenges posed by this scenario. This use case and others, including a deep galaxy survey and observations of Galactic HII regions, are guiding development of the NIRSpec user interfaces including proposal planning and pipeline calibrations.

  16. Observation of runaway electrons by infrared camera in J-TEXT.

    PubMed

    Tong, R H; Chen, Z Y; Zhang, M; Huang, D W; Yan, W; Zhuang, G

    2016-11-01

    When the energy of confined runaway electrons approaches several tens of MeV, the runaway electrons can emit synchrotron radiation in the range of infrared wavelength. An infrared camera working in the wavelength of 3-5 μm has been developed to study the runaway electrons in the Joint Texas Experimental Tokamak (J-TEXT). The camera is located in the equatorial plane looking tangentially into the direction of electron approach. The runaway electron beam inside the plasma has been observed at the flattop phase. With a fast acquisition of the camera, the behavior of runaway electron beam has been observed directly during the runaway current plateau following the massive gas injection triggered disruptions.

  17. Observation of runaway electrons by infrared camera in J-TEXT

    NASA Astrophysics Data System (ADS)

    Tong, R. H.; Chen, Z. Y.; Zhang, M.; Huang, D. W.; Yan, W.; Zhuang, G.

    2016-11-01

    When the energy of confined runaway electrons approaches several tens of MeV, the runaway electrons can emit synchrotron radiation in the range of infrared wavelength. An infrared camera working in the wavelength of 3-5 μm has been developed to study the runaway electrons in the Joint Texas Experimental Tokamak (J-TEXT). The camera is located in the equatorial plane looking tangentially into the direction of electron approach. The runaway electron beam inside the plasma has been observed at the flattop phase. With a fast acquisition of the camera, the behavior of runaway electron beam has been observed directly during the runaway current plateau following the massive gas injection triggered disruptions.

  18. Centaurs and Scattered Disk Objects in the Thermal Infrared: Analysis of WISE/NEOWISE Observations

    NASA Astrophysics Data System (ADS)

    Bauer, James M.; Grav, Tommy; Blauvelt, Erin; Mainzer, A. K.; Masiero, Joseph R.; Stevenson, Rachel; Kramer, Emily; Fernández, Yan R.; Lisse, C. M.; Cutri, Roc M.; Weissman, Paul R.; Dailey, John W.; Masci, Frank J.; Walker, Russel; Waszczak, Adam; Nugent, Carrie R.; Meech, Karen J.; Lucas, Andrew; Pearman, George; Wilkins, Ashlee; Watkins, Jessica; Kulkarni, Shrinivas; Wright, Edward L.; WISE Team; PTF Team

    2013-08-01

    The Wide-field Infrared Survey Explorer (WISE) observed 52 Centaurs and scattered disk objects (SDOs) in the thermal infrared, including 15 new discoveries. We present analyses of these observations to estimate sizes and mean optical albedos. We find mean albedos of 0.08 ± 0.04 for the entire data set. Thermal fits yield average beaming parameters of 0.9 ± 0.2 that are similar for both SDO and Centaur sub-classes. Biased cumulative size distributions yield size-frequency distribution power law indices of ~-1.7 ± 0.3. The data also reveal a relation between albedo and color at the 3σ level. No significant relation between diameter and albedos is found.

  19. CENTAURS AND SCATTERED DISK OBJECTS IN THE THERMAL INFRARED: ANALYSIS OF WISE/NEOWISE OBSERVATIONS

    SciTech Connect

    Bauer, James M.; Grav, Tommy; Blauvelt, Erin; Collaboration: WISE Team; PTF Team; and others

    2013-08-10

    The Wide-field Infrared Survey Explorer (WISE) observed 52 Centaurs and scattered disk objects (SDOs) in the thermal infrared, including 15 new discoveries. We present analyses of these observations to estimate sizes and mean optical albedos. We find mean albedos of 0.08 {+-} 0.04 for the entire data set. Thermal fits yield average beaming parameters of 0.9 {+-} 0.2 that are similar for both SDO and Centaur sub-classes. Biased cumulative size distributions yield size-frequency distribution power law indices of {approx}-1.7 {+-} 0.3. The data also reveal a relation between albedo and color at the 3{sigma} level. No significant relation between diameter and albedos is found.

  20. X-Ray and Infrared Observations of Embedded Young Stars in NGC 2264

    NASA Technical Reports Server (NTRS)

    Simon, Theordore; Dahm, S. E.

    2005-01-01

    Images of the NGC 2264 star-forming region, which we have acquired with the XMM-Newton spacecraft, reveal strong X-ray emission from three deeply embedded (Av > 10 mag) young stellar objects in the vicinity of Allen's infrared source (AFGL 989 = IRS 1) and Castelaz & Grasdalen s infrared source (RNO-EW = IRS 2). Thermal plasma models for the brightest source in X-rays, located 11 southwest of Allen's star, yield a quasi-steady luminosity of Lx = 10 ergs s-1 and an extraordinarily high X-ray temperature of 100 MK. The high temperature is consistent with the presence of emission lines of Fe xxv and Fe xxvi at photon energies of 6.7 and 6.9 keV, respectively. An even higher temperature of nearly 140 MK was observed during the rise phase of a powerful impulsive X-ray flare of another young star in the IRS 2 region. Moderate-resolution near-infrared (1-4 um) spectra of the embedded objects, obtained at the NASA Infrared Telescope Facility, exhibit deep water ice absorption bands, as well as a variety of emission and absorption features of H I, CO, and both neutral and ionized metals.

  1. Near-Infrared, Adaptive Optics Observations of the T Tauri Multiple-Star System

    NASA Astrophysics Data System (ADS)

    Furlan, Elise; Forrest, William J.; Watson, Dan M.; Uchida, Keven I.; Brandl, Bernhard R.; Keller, Luke D.; Herter, Terry L.

    2003-10-01

    With high angular resolution, near-infrared observations of the young stellar object T Tauri at the end of 2002, we show that, contrary to previous reports, none of the three infrared components of T Tau seem to coincide with the compact radio source that has apparently been ejected recently from the system (Loinard, Rodríguez, & Rodríguez). The compact radio source and the infrared object it has previously been identified with, T Tau Sb, have distinct paths that departed from orbital or uniform motion between 1997 and 2000, perhaps indicating that their interaction led to the ejection of the radio source. The path that T Tau Sb took between 1997 and 2003 may indicate that this star is still bound to the presumably more massive southern component, T Tau Sa. The radio source (if indeed distinct from T Tau Sb) is absent from our near-infrared images and must therefore be fainter than K=10.2 (if located within 100 mas of T Tau Sb, as the radio data would imply), still consistent with an identity as a low-mass star or substellar object.

  2. 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.

  3. Cloud mask via cumulative discriminant analysis applied to satellite infrared observations: scientific basis and initial evaluation

    NASA Astrophysics Data System (ADS)

    Amato, U.; Lavanant, L.; Liuzzi, G.; Masiello, G.; Serio, C.; Stuhlmann, R.; Tjemkes, S. A.

    2014-10-01

    We introduce a classification method (cumulative discriminant analysis) of the discriminant analysis type to discriminate between cloudy and clear-sky satellite observations in the thermal infrared. The tool is intended for the high-spectral-resolution infrared sounder (IRS) planned for the geostationary METEOSAT (Meteorological Satellite) Third Generation platform and uses IASI (Infrared Atmospheric Sounding Interferometer) data as a proxy. The cumulative discriminant analysis does not introduce biases intrinsic with the approximation of the probability density functions and is flexible enough to adapt to different strategies to optimize the cloud mask. The methodology is based on nine statistics computed from IASI spectral radiances, which exploit the high spectral resolution of the instrument and which effectively summarize information contained within the IASI spectrum. A principal component analysis prior step is also introduced, which makes the problem more consistent with the statistical assumptions of the methodology. An initial assessment of the scheme is performed based on global and regional IASI real data sets and cloud masks obtained from AVHRR (Advanced Very High Resolution Radiometer) and SEVIRI (Spinning Enhanced Visible and Infrared Imager) imagers. The agreement with these independent cloud masks is generally well above 80 %, except at high latitudes in the winter seasons.

  4. Cloud mask via cumulative discriminant analysis applied to satellite infrared observations: scientific basis and initial evaluation

    NASA Astrophysics Data System (ADS)

    Amato, U.; Lavanant, L.; Liuzzi, G.; Masiello, G.; Serio, C.; Stuhlmann, R.; Tjemkes, S. A.

    2014-06-01

    We introduce a classification method (Cumulative Discriminant Analysis) of the Discriminant Analysis type to discriminate between cloudy and clear sky satellite observations in the thermal infrared. The tool is intended for the high spectral resolution infrared sounder (IRS) planned for the geostationary METEOSAT (Meteorological Satellite) Third Generation platform and uses IASI (Infrared Atmospheric Sounding Interferometer) data as a proxy. The Cumulative Discriminant Analysis does not introduce biases intrinsic with the approximation of the probability density functions and is flexible enough to adapt to different strategies to optimize the cloud mask. The methodology is based on nine statistics computed from IASI spectral radiances, which exploit the high spectral resolution of the instrument and which effectively summarize information contained within the IASI spectrum. A Principal Component Analysis prior step is also introduced which makes the problem more consistent with the statistical assumptions of the methodology. An initial assessment of the scheme is performed based on global and regional IASI real data sets and cloud masks obtained from AVHRR (Advanced Very High Resolution Radiometer) and SEVIRI (Spinning Enhanced Visible and Infrared Imager) imagers. The agreement with these independent cloud masks is generally well above 80%, except at high latitudes in their winter seasons.

  5. Characteristics of Titan's haze derived from solar occultation observations in the infrared

    NASA Astrophysics Data System (ADS)

    Sotin, Christophe; Lawrence, Kenneth J.; Marmuse, Florian; Xu, Feng; West, Robert; Brown, Robert H.; Baines, Kevin; Buratti, Bonnie J.; Clark, Roger Nelson; Nicholson, Philip D.

    2016-10-01

    The Visual and Infrared Mapping Spectrometer (VIMS) has acquired 14 solar occultation observations between January 2006 and April 2016. The observations span a large range of latitude and seasons, allowing us to witness atmospheric variability. We use only the infrared channel of the VIMS instrument between 884- and 5108-nm. The observations are first processed to provide light curves which are the transmission through Titan's atmosphere as a function of the impact parameter. The transmission is calculated by dividing the signal by the solar spectrum obtained when the value of the impact parameter is much larger than the thickness of Titan's atmosphere, which makes it independent of the choice of the solar spectrum. The data set is composed of 14 3D arrays (transmission, wavelength, impact parameter). Errors are calculated using the SNR derived from the acquisition of the solar spectra and the value of transmission. The observations use a solar port which is aligned with the UVIS boresight in order to simultaneously record the atmospheric transmission in both UV and IR. For this purpose, VIMS has a solar port. However, one difficulty is to remove the additional light that often comes from the boresight. The technic will be described. In the seven infrared wavelengths where Titan's surface can be observed, the transmission is a direct measurement of the scattering by the aerosols. An inversion process has been set up to provide the density distribution of the aerosols as a function of altitude for each of these observations. The model is simple model with only one population of aerosols with a cross section that is wavelength-dependent. The model allows us to provide extinction curves at those wavelengths. The three observations obtained at the equator, close to where the Huygens probe landed, are compared with the DISR observations which have been recently revised (Doose et al., Icarus, 2016).This work has been performed at the Jet Propulsion Laboratory, California

  6. Infrared observations of IGR J17497-2821: new position, new candidate counterparts

    NASA Astrophysics Data System (ADS)

    Chaty; S.; Hatano; H.; Matsuoka; Y.; Nagata; T.

    2006-10-01

    Following the report by Kennea et al. (Atel #900) of a new Swift/XRT position for the recently discovered source IGR J17497-2821 (see Soldi et al., atel #885), we inspected our infrared (IR) images obtained in J, H and Ks bands of the field of IGR J17497-2821 at 1.4m IRSF at South African Astronomical Observatory (details on the observations and reduction are given in Chaty et al., atel #897).

  7. The Near-Earth Encounter of 2005 YU55: Thermal Infrared Observations from Gemini North

    NASA Technical Reports Server (NTRS)

    Lim, Lucy F.; Emery, Joshua P.; Moskovitz, Nicholas A.; Granvik, Mikael

    2012-01-01

    As part of a multi-observatory campaign to observe 2005 YU55 during its November 2011 encounter with the Earth, thermal infrared photometry and spectroscopy (7.9- 14 and 18-22 micron) were conducted using the Michelle instrument at Gemini North. Reduction of the 8.8 flm photometry and the spectroscopy from UT Nov-IO as well as of all the Gemini data from UT Nov-9 is in progress. Results will be discussed.

  8. Observation of the infrared spectrum of the triatomic deuterium molecular ion D/sub 3/ /sup +/

    SciTech Connect

    Shy, J.; Farley, J.W.; Lamb, W.E. Jr.; Wing, W.H.

    1980-08-18

    The infrared vibrational-rotational spectrum of the D/sub 3/ /sup +/ isotope of the simplest poly-atomic molecule is observed. Eight intervals between 1750 and 1850 cm/sup -1/ have been measured to an error of 0.0005 cm/sup -1/ or 0.3 ppm (at 70% confidence level). Four have been identified as members of the fundamental degenerate vibrational band. The rest apparently involve unidentified higher vibrational-rotational levels.

  9. The Convection of Close Red Supergiant Stars Observed With Near-Infrared Interferometry

    NASA Astrophysics Data System (ADS)

    Montargès, M.; Kervella, P.; Perrin, G.; Chiavassa, A.; Aurière, M.

    2015-12-01

    Our team has obtained observations of the photosphere of the two closest red supergiant stars Betelgeuse (α Ori) and Antares (α Sco) using near infrared interferometry. We have been monitoring the photosphere of Betelgeuse with the VLTI/PIONIER instrument for three years. On Antares, we obtained an unprecedented sampling of the visibility function. These data allow us to probe the convective photosphere of massive evolved stars.

  10. Impact of Spectroscopic Line Parameters on Carbon Monoxide Column Density Retrievals from Shortwave Infrared Nadir Observations

    NASA Astrophysics Data System (ADS)

    Schmidt, Denise; Gimeno Garcia, Sebastian; Schreier, Franz; Lichtenberg, Gunter

    2015-11-01

    Among the various input data required for the retrieval of atmospheric state parameters from infrared remote sensing observations molecular spectroscopy line data have a central role, because their quality is critical for the quality of the final product. Here we discuss the impact of the line parameters on vertical column densities (VCD) estimated from short wave infrared nadir observations. Using BIRRA (the Beer InfraRed Retrieval Algorithm) comprising a line-by-line radiative transfer code (forward model) and a separable nonlinear least squares solver for inversion we retrieve carbon monoxide from observations of SCIAMACHY aboard Envisat. Retrievals using recent versions of HITRAN und GEISA have been performed and the results are compared in terms of residual norms, molecular density scaling factors, their corresponding errors, and the final VCD product. The retrievals turn out to be quite similar for all three databases, so a definite recommendation in favor of one of these databases is difficult for the considered spectral range around 2.3 μm. Nevertheless, HITRAN 2012 appears to be advantageous when evaluating the different quality criteria.

  11. Using Near Infrared Observations and Models to Analyze Surface Compositions of Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    McGuire, Ryan

    Kuiper Belt Objects (KBOs) are primordial icy objects in the outer solar system. Compositional information for KBOs helps us understand the original environment of the solar system as well as identify objects that are compositionally anomalous. Due to the faint nature of KBOs, very few spectroscopic observations have been made of them. Instead, photometric observations at infrared wavelengths are made to partially construct their spectra. I calculate near infrared reflectances for 12 objects using photometric observations from the Gemini North telescope. I combine these near infrared reflectances with data from the Spitzer Space Telescope. This combination of Gemini and Spitzer photometry along with compositional model analysis allows us to find the surface composition (organics, H2O, CO2, CH4, and other hydrated silicates) for these 12 objects. I found that my objects fit into one of four taxonomic classes found in the Kuiper Belt. We have found using the color analysis, that Haumea has water on its surface and Eris is most likely to have methane on its surface. By analyzing this data we measure the compositional mixing in the outer solar system.

  12. Multi-Wavelength Observations of Asteroid 2100 Ra-Shalom: Visible, Infrared, and Thermal Spectroscopy Results

    NASA Technical Reports Server (NTRS)

    Clark, Beth Ellen; Shepard, M.; Bus, S. J.; Vilas, F.; Rivkin, A. S.; Lim, L.; Lederer, S.; Jarvis, K.; Shah, S.; McConnochie, T.

    2004-01-01

    The August 2003 apparition of asteroid 2100 Ra-Shalom brought together a collaboration of observers with the goal of obtaining rotationally resolved multiwavelength spectra at each of 5 facilities: infrared spectra at the NASA Infrared Telescope Facility (Clark and Shepard), radar images at Arecibo (Shepard and Clark), thermal infrared spectra at Palomar (Lim, McConnochie and Bell), visible spectra at McDonald Observatory (Vilas, Lederer and Jarvis), and visible lightcurves at Ondrojev Observatory (Pravec). The radar data was to be used to develop a high spatial resolution physical model to be used in conjunction with spectral data to investigate compositional and textural properties on the near surface of Ra Shalom as a function of rotation phase. This was the first coordinated multi-wavelength investigation of any Aten asteroid. There are many reasons to study near-Earth asteroid (NEA) 2100 Ra-Shalom: 1) It has a controversial classification (is it a C- or K-type object)? 2) There would be interesting dynamical ramifications if Ra-Shalom is a K-type because most K-types come from the Eos family and there are no known dynamical pathways from Eos to the Aten population. 3) The best available spectra obtained previously may indicate a heterogeneous surface (most asteroids appear to be fairly homogeneous). 4) Ra-Shalom thermal observations obtained previously indicated a lack of regolith, minimizing the worry of space weathering effects in the spectra. 5) Radar observations obtained previously hinted at interesting surface structures. 6) Ra-Shalom is one of the largest Aten objects. And 7) Ra-Shalom is on a short list of proposed NEAs for spacecraft encounters and possible sample returns. Preliminary results from the visible, infrared, and thermal spectroscopy measurements will be presented here.

  13. Titan Aerosol Analogs from Aromatic Precursors: Comparisons to Cassini CIRS Observations in the Thermal Infrared

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    Since Cassini's arrival at Titan, ppm levels of benzene (C6H6) as well as large positive ions, which may be polycyclic aromatic hydrocarbons (PAHs). have been detected in the atmosphere. Aromatic molecules. photolytically active in the ultraviolet, may be important in the formation of the organic aerosol comprising the Titan haze layer even when present at low mixing ratios. Yet there have not been laboratory simulations exploring the impact of these molecules as precursors to Titan's organic aerosol. Observations of Titan by the Cassini Composite Infrared Spectrometer (CIRS) in the far-infrared (far-IR) between 560 and 20/cm (approx. 18 to 500 microns) and in the mid-infrared (mid-IR) between 1500 and 600/cm (approx. 7 to 17 microns) have been used to infer the vertical variations of Titan's aerosol from the surface to an altitude of 300 km in the far-IR and between 150 and 350 km in the mid-IR. Titan's aerosol has several observed emission features which cannot be reproduced using currently available optical constants from laboratory-generated Titan aerosol analogs, including a broad far-IR feature centered approximately at 140/cm (71 microns).

  14. The infrared database of extragalactic observables from Spitzer - I. The redshift catalogue

    NASA Astrophysics Data System (ADS)

    Hernán-Caballero, Antonio; Spoon, Henrik W. W.; Lebouteiller, Vianney; Rupke, David S. N.; Barry, Donald P.

    2016-01-01

    This is the first of a series of papers on the Infrared Database of Extragalactic Observables from Spitzer (IDEOS). In this work, we describe the identification of optical counterparts of the infrared sources detected in Spitzer Infrared Spectrograph (IRS) observations, and the acquisition and validation of redshifts. The IDEOS sample includes all the spectra from the Cornell Atlas of Spitzer/IRS Sources (CASSIS) of galaxies beyond the Local Group. Optical counterparts were identified from correlation of the extraction coordinates with the NASA Extragalactic Database (NED). To confirm the optical association and validate NED redshifts, we measure redshifts with unprecedented accuracy on the IRS spectra (σ(Δz/(1+z)) ˜ 0.0011) by using an improved version of the maximum combined pseudo-likelihood method (MCPL). We perform a multistage verification of redshifts that considers alternate NED redshifts, the MCPL redshift, and visual inspection of the IRS spectrum. The statistics is as follows: the IDEOS sample contains 3361 galaxies at redshift 0 < z < 6.42 (mean: 0.48, median: 0.14). We confirm the default NED redshift for 2429 sources and identify 124 with incorrect NED redshifts. We obtain IRS-based redshifts for 568 IDEOS sources without optical spectroscopic redshifts, including 228 with no previous redshift measurements. We provide the entire IDEOS redshift catalogue in machine-readable formats. The catalogue condenses our compilation and verification effort, and includes our final evaluation on the most likely redshift for each source, its origin, and reliability estimates.

  15. Alma observations of nearby luminous infrared galaxies with various agn energetic contributions using dense gas tracers

    SciTech Connect

    Imanishi, Masatoshi; Nakanishi, Kouichiro

    2014-07-01

    We present the results of our ALMA Cycle 0 observations, using HCN/HCO{sup +}/HNC J = 4-3 lines, of six nearby luminous infrared galaxies with various energetic contributions from active galactic nuclei (AGNs) estimated from previous infrared spectroscopy. These lines are very effective for probing the physical properties of high-density molecular gas around the hidden energy sources in the nuclear regions of these galaxies. We find that HCN to HCO{sup +} J = 4-3 flux ratios tend to be higher in AGN-important galaxies than in starburst-dominated regions, as was seen at the J = 1-0 transition, while there is no clear difference in the HCN-to-HNC J = 4-3 flux ratios among observed sources. A galaxy with a starburst-type infrared spectral shape and very large molecular line widths shows a high HCN-to-HCO{sup +} J = 4-3 flux ratio, which could be due to turbulence-induced heating. We propose that enhanced HCN J = 4-3 emission relative to HCO{sup +} J = 4-3 could be used to detect more energetic activity than normal starbursts, including deeply buried AGNs, in dusty galaxy populations.

  16. 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.

  17. Measurements of C02 Distribution in Saturn's Atmosphere by Cassini-Infrared Observations

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; LeClair, A.; Woodard, E.; Young, M.; Stanbro, M.; Flasar, M.

    2013-01-01

    The Fourier transform infrared spectrometer aboard the Cassini spacecraft, inserted in Saturn s orbit in July 2004, has been providing high resolution/high sensitivity infrared (IR) spectra of the Saturnian system. The measurements cover the spectral range of 10-1400/cm with variable spectral resolutions of 0.53 to 15/cm, exhibiting spectral features of a series of trace gases including CO2 and H2O. The observed spectra may be analyzed for retrieval of global P/T and gas density profiles of Saturn. The infrared measurements of Saturn by ISO(SWS) have indicated unexpected large abundances of CO2 in Saturn's atmosphere. The rigorous photochemical models of Saturn's atmosphere that have been developed indicate exogenic oxygen influx of icy dust grains that lead to the production of CO2. The distribution of CO2 in Saturn's atmosphere needs to be confirmed, and the nature of exogenic sources remains to be investigated. This paper presents comprehensive measurements of the CO2 distribution in Saturn's atmosphere by Cassini IR observations.

  18. Centaurs and Scattered Disk Objects in the Thermal Infrared: Analysis of WISE/NEOWISE Observations

    NASA Astrophysics Data System (ADS)

    Bauer, James M.; Grav, T.; Mainzer, A. K.; Masiero, J. R.; Blauvelt, E.; Stevenson, R.; Kramer, E.; Fernandez, Y. R.; Lisse, C. M.; Cutri, R. M.; Weissman, P. R.; Dailey, J. W.; Masci, F. J.; Walker, R.; Waszczak, A.; Nugent, C. R.; Meech, K. J.; Lucas, A.; Pearman, G.; Wilkins, A.; Watkins, J.; Kulkarni, S.; Wright, E. L.; WISE Team; PTF Team

    2013-10-01

    The Wide-field Infrared Survey Explorer (WISE) observed 52 Centaurs and Scattered Disk Objects in the thermal infrared, including discoveries of 15 previously unknown objects. At this writing, this is the largest published collection of thermal infrared measurements of Centaur and SDOs. We present analyses of these observations to estimate sizes and mean optical albedos derived from photometry of the WISE images taken simultaneously at wavelengths of 3.4, 4.6, 12, and 22 microns. We find mean visual-wavelength geometric albedos of 0.08, +/- 0.04 standard deviations, for the entire data set. Thermal fits yield average beaming parameters of 0.9 +/- 0.2 that are similar for both SDO and Centaur sub-classes, and there appears to be no trend of beaming with heliocentric distance. Raw cumulative size distributions for objects with diameters > 20 km yield size-frequency distribution power law indices ~ -1.7 +/- 0.3. The data also reveal a relation between albedo and color at the 3-sigma level, with those objects with visual-wavelength B-R colors < 1.4 magnitudes having significantly lower albedos than those with B-R colors exceeding 1.4 magnitudes. No significant relation between diameter and albedos is found. We will also discuss the implications of these survey results concerning the related comet and TNO populations.

  19. Physical properties (particle size, rock abundance) from thermal infrared remote observations: Implications for Mars landing sites

    NASA Technical Reports Server (NTRS)

    Christensen, P. R.; Edgett, Kenneth S.

    1994-01-01

    Critical to the assessment of potential sites for the 1997 Pathfinder landing is estimation of general physical properties of the martian surface. Surface properties have been studied using a variety of spacecraft and earth-based remote sensing observations, plus in situ studies at the Viking lander sites. Because of their value in identifying landing hazards and defining scientific objectives, we focus this discussion on thermal inertia and rock abundance derived from middle-infrared (6 to 30 microns) observations. Used in conjunction with other datasets, particularly albedo and Viking orbiter images, thermal inertia and rock abundance provide clues about the properties of potential Mars landing sites.

  20. Adding Emission Line Diagnostics To The Infrared Database of Extragalactic Observables from Spitzer (IDEOS)

    NASA Astrophysics Data System (ADS)

    Spoon, Henrik

    During the cryogenic phase of the successful Spitzer mission the Infrared Spectrograph (IRS) made observations of about 15,000 objects. Among these are low-resolution (highresolution) spectra of more than 4200 (1800) galaxies beyond the Local Group. Results have been published in a great number of papers, led not only by hardcore infrared observers but increasingly also by non-native infrared astronomers. As the PI team of the IRS instrument, we are especially proud of the achievements of the IRS spectrograph, and we feel a special obligation to enhance the legacy value of its many observations. In 2011 we completed the Cornell Atlas of Spitzer-IRS Sources (CASSIS), containing homogeneously, expert-reduced low-resolution IRS spectra for over 13,000 observations. Earlier this year we added more than 7,000 spectra obtained with the high-resolution modules. All of these spectra benefit from the availability of our empirically derived super-sampled point-spread functions, which reduce the effects of bad and low-level rogue pixels in all IRS modules. All spectra are available for download from our CASSIS web portal. Building on this legacy, in 2013 we also started working on the soon to be completed Infrared Database of Extragalactic Observables from Spitzer (IDEOS), which contains mid-IR observables extracted from the low-resolution spectra in CASSIS. IDEOS provides astronomers with widely varying scientific interests access to diagnostics that were previously available only for limited samples, or available on the-fly only to expert users. Here we propose to continue these efforts by measuring the emission line fluxes for 3,000-4,500 galaxies in the CASSIS atlas to add powerful emission line diagnostics to our existing suite of mid-IR observables in IDEOS. IDEOS will be a great asset for future users of NASA's James Webb Space Telescope to select their samples and estimate required integration times. The completion of IDEOS will further coincide with the completion of

  1. Inference of Surface Chemical and Physical Properties Using Mid-Infrared (MIR) Spectral Observations

    NASA Technical Reports Server (NTRS)

    Roush, Ted L.

    2016-01-01

    Reflected or emitted energy from solid surfaces in the solar system can provide insight into thermo-physical and chemical properties of the surface materials. Measurements have been obtained from instruments located on Earth-based telescopes and carried on several space missions. The characteristic spectral features commonly observed in Mid-Infrared (MIR) spectra of minerals will be reviewed, along with methods used for compositional interpretations of MIR emission spectra. The influence of surface grain size, and space weathering processes on MIR emissivity spectra will also be discussed. Methods used for estimating surface temperature, emissivity, and thermal inertias from MIR spectral observations will be reviewed.

  2. Infrared observations of the galactic center. I - Nature of the compact sources

    NASA Technical Reports Server (NTRS)

    Becklin, E. E.; Matthews, K.; Neugebauer, G.; Willner, S. P.

    1978-01-01

    Photometry from 1.25 to 12 micrometers and spectrophotometry from 8 to 13 micrometers of the compact sources found in the galactic-center region are reported. In addition, revised 10 and new 20 micrometers maps with 2''.3 resolution are given. The nature of the compact sources is discussed. Some are best identified as stars or star clusters; the brightest source at 2 micrometers is probably a supergiant, and the infrared source near the nonthermal radio source is probably a stellar cluster with density greater than 1 million solar masses/cu pc. Other sources emit most of their luminosity at wavelengths of 10 micrometers and greater; this emission is probably from heated dust. One of the sources is observationally similar to extremely red OH/infrared stars. Other sources have luminosities and linear sizes similar to those of compact H II regions; emission from optically thin silicate dust is seen in these.

  3. Infrared observations of NGC 2071/IRS/ and AFGL 490 - Two low-luminosity young stars

    NASA Technical Reports Server (NTRS)

    Harvey, P. M.; Campbell, M. F.; Hoffmann, W. F.; Thronson, H. A., Jr.; Gatley, I.

    1979-01-01

    Infrared observations are presented of two compact sources associated with molecular clouds. Photometry from 2 to 200 microns of the source associated with an OH maser in NGC 2071, OH 205.1-14.1, shows a steep increase in flux from 2 to 50 microns. Scans at several wavelengths fail to resolve the source. Photometry at 50-200 microns of the other object, GL 490, when combined with earlier 2-20-micron spectrophotometry, shows an infrared energy distribution that is much broader than that of the NGC 2071 source. Both sources are interpreted as young, possibly pre-main-sequence objects with differences in energy distributions due principally to differences in the distribution of circumstellar matter.

  4. Direct observation of narrow mid-infrared plasmon linewidths of single metal oxide nanocrystals

    NASA Astrophysics Data System (ADS)

    Johns, Robert W.; Bechtel, Hans A.; Runnerstrom, Evan L.; Agrawal, Ankit; Lounis, Sebastien D.; Milliron, Delia J.

    2016-05-01

    Infrared-responsive doped metal oxide nanocrystals are an emerging class of plasmonic materials whose localized surface plasmon resonances (LSPR) can be resonant with molecular vibrations. This presents a distinctive opportunity to manipulate light-matter interactions to redirect chemical or spectroscopic outcomes through the strong local electric fields they generate. Here we report a technique for measuring single nanocrystal absorption spectra of doped metal oxide nanocrystals, revealing significant spectral inhomogeneity in their mid-infrared LSPRs. Our analysis suggests dopant incorporation is heterogeneous beyond expectation based on a statistical distribution of dopants. The broad ensemble linewidths typically observed in these materials result primarily from sample heterogeneity and not from strong electronic damping associated with lossy plasmonic materials. In fact, single nanocrystal spectra reveal linewidths as narrow as 600 cm-1 in aluminium-doped zinc oxide, a value less than half the ensemble linewidth and markedly less than homogeneous linewidths of gold nanospheres.

  5. Crystalline and Amorphous Ice on Enceladus: Observations from the Cassini Visual Infrared Mapping Spectrometer (VIMS)

    NASA Astrophysics Data System (ADS)

    Newman, Sarah; Buratti, B. J.; Brown, R. H.; Jaumann, R.; Bauer, J.; Momary, T.

    2006-09-01

    Photometric and spectral analysis of data from the Cassini Visual and Infrared Mapping Spectrometer (VIMS) has yielded intriguing findings regarding the properties and composition of the surface of Saturn's satellite Enceladus. Spectral cubes, which contain both spatial and spectral information, were obtained of this satellite with a wavelength distribution in the infrared far more extensive than from any previous observations. Using these cubes, we have discovered a distribution of amorphous and crystalline ices on the southern pole of Enceladus, indicating intense ion bombardment in those latitudes and recent geological activity at the "tiger stripe" linea. Using a composite mosaic of the satellite, we map this distribution of ices according to a "crystallinity factor" and consider investigation of the time scale of the geologic activity on the surface of Enceladus based on amorphization rates in the outer Solar System. Work funded by NASA.

  6. Direct observation of narrow mid-infrared plasmon linewidths of single metal oxide nanocrystals

    PubMed Central

    Johns, Robert W.; Bechtel, Hans A.; Runnerstrom, Evan L.; Agrawal, Ankit; Lounis, Sebastien D.; Milliron, Delia J.

    2016-01-01

    Infrared-responsive doped metal oxide nanocrystals are an emerging class of plasmonic materials whose localized surface plasmon resonances (LSPR) can be resonant with molecular vibrations. This presents a distinctive opportunity to manipulate light–matter interactions to redirect chemical or spectroscopic outcomes through the strong local electric fields they generate. Here we report a technique for measuring single nanocrystal absorption spectra of doped metal oxide nanocrystals, revealing significant spectral inhomogeneity in their mid-infrared LSPRs. Our analysis suggests dopant incorporation is heterogeneous beyond expectation based on a statistical distribution of dopants. The broad ensemble linewidths typically observed in these materials result primarily from sample heterogeneity and not from strong electronic damping associated with lossy plasmonic materials. In fact, single nanocrystal spectra reveal linewidths as narrow as 600 cm−1 in aluminium-doped zinc oxide, a value less than half the ensemble linewidth and markedly less than homogeneous linewidths of gold nanospheres. PMID:27174681

  7. Direct observation of narrow mid-infrared plasmon linewidths of single metal oxide nanocrystals

    DOE PAGES

    Johns, Robert W.; Bechtel, Hans A.; Runnerstrom, Evan L.; ...

    2016-05-13

    Infrared-responsive doped metal oxide nanocrystals are an emerging class of plasmonic materials whose localized surface plasmon resonances (LSPR) can be resonant with molecular vibrations. This presents a distinctive opportunity to manipulate light-matter interactions to redirect chemical or spectroscopic outcomes through the strong local electric fields they generate. Here we report a technique for measuring single nanocrystal absorption spectra of doped metal oxide nanocrystals, revealing significant spectral inhomogeneity in their mid-infrared LSPRs. Our analysis suggests dopant incorporation is heterogeneous beyond expectation based on a statistical distribution of dopants. The broad ensemble linewidths typically observed in these materials result primarily from sammore » ple heterogeneity and not from strong electronic damping associated with lossy plasmonic materials. In fact, single nanocrystal spectra reveal linewidths as narrow as 600 cm -1 in aluminium-doped zinc oxide, a value less than half the ensemble linewidth and markedly less than homogeneous linewidths of gold nanospheres.« less

  8. Direct observation of narrow mid-infrared plasmon linewidths of single metal oxide nanocrystals

    SciTech Connect

    Johns, Robert W.; Bechtel, Hans A.; Runnerstrom, Evan L.; Agrawal, Ankit; Lounis, Sebastien D.; Milliron, Delia J.

    2016-05-13

    Infrared-responsive doped metal oxide nanocrystals are an emerging class of plasmonic materials whose localized surface plasmon resonances (LSPR) can be resonant with molecular vibrations. This presents a distinctive opportunity to manipulate light-matter interactions to redirect chemical or spectroscopic outcomes through the strong local electric fields they generate. Here we report a technique for measuring single nanocrystal absorption spectra of doped metal oxide nanocrystals, revealing significant spectral inhomogeneity in their mid-infrared LSPRs. Our analysis suggests dopant incorporation is heterogeneous beyond expectation based on a statistical distribution of dopants. The broad ensemble linewidths typically observed in these materials result primarily from sam ple heterogeneity and not from strong electronic damping associated with lossy plasmonic materials. In fact, single nanocrystal spectra reveal linewidths as narrow as 600 cm -1 in aluminium-doped zinc oxide, a value less than half the ensemble linewidth and markedly less than homogeneous linewidths of gold nanospheres.

  9. Current Sounding Capability From Satellite Meteorological Observation With Ultraspectral Infrared Instruments

    NASA Technical Reports Server (NTRS)

    Zhou, Daniel K.; Liu, Xu; Larar, Allen M.

    2008-01-01

    Ultraspectral resolution infrared spectral radiance obtained from near nadir observations provide atmospheric, surface, and cloud property information. The intent of the measurement of tropospheric thermodynamic state and trace abundances is the initialization of climate models and the monitoring of air quality. The NPOESS Airborne Sounder Testbed-Interferometer (NAST-I), designed to support the development of future satellite temperature and moisture sounders, aboard high altitude aircraft has been collecting data throughout many field campaigns. An advanced retrieval algorithm developed with NAST-I is now applied to satellite data collected with the Atmospheric InfraRed Sounder (AIRS) on the Aqua satellite launched on 4 May 2002 and the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp satellite launched on October 19, 2006. These instruments possess an ultra-spectral resolution, for example, both IASI and NAST-I have 0.25 cm-1 and a spectral coverage from 645 to 2760 cm-1. The retrieval algorithm with a fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. The physical inversion scheme has been developed, dealing with cloudy as well as cloud-free radiance observed with ultraspectral infrared sounders, to simultaneously retrieve surface, atmospheric thermodynamic, and cloud microphysical parameters. A fast radiative transfer model, which applies to the clouded atmosphere, is used for atmospheric profile and cloud parameter retrieval. A one-dimensional (1-d) variational multi-variable inversion solution is used to improve an iterative background state defined by an eigenvector-regression-retrieval. The solution is iterated in order to account for non-linearity in the 1-d variational solution. It is shown that relatively accurate temperature and moisture retrievals can be achieved below optically thin clouds. For optically thick clouds, accurate temperature and moisture profiles down to

  10. Infrared observations of white dwarfs and the implications for the accretion of dusty planetary material

    NASA Astrophysics Data System (ADS)

    Bonsor, Amy; Farihi, Jay; Wyatt, Mark C.; van Lieshout, Rik

    2017-06-01

    Infrared excesses around metal-polluted white dwarfs have been associated with the accretion of dusty planetary material. This work analyses the available infrared data for an unbiased sample of white dwarfs and demonstrates that no more than 3.3 per cent can have a wide, flat, opaque dust disc, extending to the Roche radius, with a temperature at the disc inner edge of Tin = 1400 K, the standard model for the observed excesses. This is in stark contrast to the incidence of pollution of about 30 per cent. We present four potential reasons for the absence of an infrared excess in polluted white dwarfs, depending on their stellar properties and inferred accretion rates: (i) their dust discs are opaque, but narrow, thus evading detection if more than 85 per cent of polluted white dwarfs have dust discs narrower than δr < 0.04r, (ii) their dust discs have been fully consumed, which only works for the oldest white dwarfs with sinking time-scales longer than hundreds of years, (iii) their dust is optically thin, which can supply low accretion rates of <107 gs-1 if dominated by (Poynting-Robertson) PR-drag, and higher accretion rates, if inwards transport of material is enhanced, e.g. due to the presence of gas, (iv) their accretion is supplied by a pure gas disc, which could result from the sublimation of optically thin dust for T* > 20 000 K. Future observations sensitive to faint infrared excesses or the presence of gas can test the scenarios presented here, thereby better constraining the nature of the material fuelling accretion in polluted white dwarfs.

  11. Mid-infrared observations of sungrazing comet C/2012 S1 (ISON) with the Subaru Telescope

    NASA Astrophysics Data System (ADS)

    Ootsubo, T.; Usui, F.; Takita, S.; Watanabe, J.; Yanamandra-Fisher, P.; Honda, M.; Kawakita, H.; Furusho, R.

    2014-07-01

    Comets are the frozen reservoirs of the early solar nebula and are made of ice and dust. The determination of the properties for cometary dust provides us insight into both the early-solar-nebula environment and the formation process of the planetary system. A silicate feature is often observed in comet spectra in the mid-infrared region and may be used for probing the early history of the solar system. In most cases, the feature shows the existence of crystalline silicate (for example, 11.3 microns) together with amorphous silicate [1,2]. Since the crystallization of silicates from amorphous ones generally requires high-temperature annealing above 800 K (e.g., [3,4]), it is believed that the crystalline silicate grains produced at the inner part of the disk were transported to the outer cold regions where the comet nuclei formed. Comet C/2012 S1 (ISON) is a long-period Oort Cloud comet, discovered in September 2012. In particular, comet ISON is a sungrazing comet, which was predicted to pass close by the Sun and the Earth and becoming a bright object. Mid-infrared observations of this new comet and investigation of the 10-micron silicate feature help us understand the formation of crystalline silicate grains in the early solar nebula. We conducted observations of comet ISON in the mid-infrared wavelength region with the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the Subaru Telescope on Mauna Kea, Hawaii [5,6,7]. The observation of comet ISON was carried out on 2013 October 19 and 21 UT. Since the weather conditions were not so good when we observed, we carried out N-band imaging observations (8.8 and 12.4 microns) and N-band low-resolution spectroscopy. The spectrum of comet ISON can be fit with the 260--265-K blackbody spectrum when we use the regions of 7.8--8.2 and 12.4--13.0 microns as the continuum. The spectrum has only a weak silicate excess feature, which may be able to attribute to small amorphous olivine grains. We could not detect a clear

  12. D/H RATIO OF TITAN FROM OBSERVATIONS OF THE CASSINI/COMPOSITE INFRARED SPECTROMETER

    SciTech Connect

    Abbas, M. M.; LeClair, A.; Kandadi, H. E-mail: andre.c.leClair@nasa.go

    2010-01-01

    The Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft, launched in 1997 October and inserted into Saturn's orbit in 2004 July for exploration of the Saturnian system, has been making observations of Titan during its close flybys. The infrared spectra of Titan observed over a wide range of latitudes cover the 10-1400 cm{sup -1} spectral region with variable apodized resolutions from 0.53 to 15 cm{sup -1}. The spectra exhibit features of the nu{sub 4} band of methane (CH{sub 4}) in the 1300 cm{sup -1} region, and the deuterated isotope of methane (CH{sub 3}D) centered around 1156 cm{sup -1}, along with features of many trace constituents in other spectral regions, comprising hydrocarbons and nitriles in Titan's atmosphere. An analysis of the observed infrared spectra in the 1300 cm{sup -1} and 1156 cm{sup -1} regions, respectively, permits retrieval of the thermal structure and the CH{sub 3}D distributions of Titan's atmosphere. In this paper, we present a comprehensive analysis of the CIRS infrared spectra for retrieval of the CH{sub 3}D abundance and the corresponding D/H ratio in Titan's atmosphere. The analysis is based on the 0.53 cm{sup -1} resolution infrared spectra obtained during the Titan flybys from 2004 July 3 to 2008 May 28 over a range of latitudes extending from 74.{sup 0}4 N to 84.{sup 0}9 S. Using the CH{sub 4} mixing ratio of 1.4 x 10{sup -2} as measured by the Gas Chromatograph and Mass Spectrometer on the Huygens probe on the Cassini mission, we determine the D/H ratio of Titan as (1.58 +- 0.16) x 10{sup -4}, where the 1sigma uncertainty includes the standard deviation due to spectral noise and the estimated errors arising from uncertainties in the temperature retrieval, the mixing ratio of CH{sub 4}, and the spectral line parameters. Comparison of this value with the previously measured values for Titan as well as in other astrophysical sources, and its possible implications are discussed.

  13. SPICA infrared coronagraph for the direct observation of exo-planets

    NASA Astrophysics Data System (ADS)

    Enya, Keigo; Spica Working Group

    2010-04-01

    We present a mid-infrared coronagraph to target the direct observation of extrasolar planets, for Space Infrared telescope for Cosmology and Astrophysics (SPICA). SPICA is a proposed JAXA-ESA mission, which will carry a telescope cooled to 5 K with a 3.5 m diameter aperture, and is planned to be launched in 2018 by an H II family rocket. The SPICA mission gives us a unique opportunity for high-contrast observations because of the large telescope aperture, the simple pupil shape, and the capability for infrared observations from space. We have commenced studies for a coronagraph for SPICA, in which this coronagraph is currently regarded as an option of the focal plane instruments. The primary target of the SPICA coronagraph is the direct observation of Jovian exo-planets. A strategy of the baseline survey and the specifications for the coronagraph instrument for the survey are introduced together. The main wavelengths and the contrast required for the observations are 3.5-27 μm, and 10 -6, respectively. Laboratory experiments were performed with a visible laser to demonstrate the principles of the coronagraphs. In an experiment using binary-shaped pupil coronagraphs, a contrast of 6.7 × 10 -8 was achieved, as derived from the linear average in the dark region and the core of the point spread function (PSF). A coronagraph by a binary-shaped pupil mask is a baseline solution for SPICA because of its feasibility and robustness. On the other hand, a laboratory experiment of the phase induced amplitude apodization/binary-mask hybrid coronagraph has been executed to obtain an option of higher performance (i.e., smaller inner working angle and higher throughput), and a contrast of 6.5 × 10 -7 was achieved with active wavefront control. Potentially important by-product of the instrument, transit monitoring for characterization of exo-planets, is also described. We also present recent progress of technology on a design of a binary-shaped pupil mask for the actual pupil of

  14. Characteriizing Hydration in Asteroids from Observations in the Stratosphere with the BOPPS Infrared Camera

    NASA Astrophysics Data System (ADS)

    Hibbitts, C.; Cheng, A. F.; Young, E. F.

    2014-12-01

    The Balloon Observation Platform for Planetary Science (BOPPS) mission is planning to observe several asteroids during its one-day mission in mid to late September, 2014. The observations of asteroids are secondary objectives designed to demonstrate the ability of the BIRC (BOPPS InfraRed Camera) to detect and characterize the extent of hydration on airless bodies. Hydrated asteroids are in part described by the presence of an infrared absorption band near 3-microns, due to the presence of OH complexed onto materials in their surfaces. This band is expected to begin near 2.6 microns, with a minimum between 2.7 and 2.8 microns based on laboratory measurements of vacuum desiccated carbonaceous meteorites materials [1]. Although this measurement is obscured in ground-based observations by the presence of water vapor in our atmosphere, the BOPPS mission will fly sufficiently high (~ 120K') that telluric water absorptions will not be present potentially enabling precise identification of hydration features on airless bodies like asteroids. The BIRC measurements will be obtained with a cryogenic infrared camera equipped with a 9-position filter wheel with each infrared filter having a FWHM of ~ 3% of the center wavelength [2]. Six of these bands are selected to characterize the OH and H2O absorption feature, and are centered at 2.45 microns, 2.73 microns, 2.85 microns, 3.05 microns, 3.2 microns, and 4 microns. The other three bands are at 0.67 microns (astronomical R-band), 4.27 microns, and 4.6 microns (these last two are to characterize CO2 emissions from comets). The BOPPS mission plans to observe both 1Ceres and 4Vesta. Ceres has a strong water/hydroxyl band [3] whose position would be well characterized by this mission and has been reported to be a variable source of water vapor emission [4] . We will report initial results of BOPPS asteroid observations. References: [1] Takir et al., (2013), Meteor. & Planet. Sci., 48, 9, 1618-1637; [2] Cheng et al., (2014), Fall

  15. Mid-infrared Observation of C/2012 S1 (ISON) with Subaru+COMCIS

    NASA Astrophysics Data System (ADS)

    Ootsubo, T.; Watanabe, J.; Honda, M.; Yanamandra-Fisher, P. A.; Usui, F.; Takita, S.; Kasuga, T.; Furusho, R.; Fuse, T.; Nagashima, M.; Kawakita, H.; Fujiyoshi, T.

    2013-12-01

    Dust grains in comets have been used to investigate the formation conditions of the solar system. A silicate feature is often observed in comets as a 10-micron resonant feature. In most cases the feature shows the existence of crystalline silicate together with amorphous silicate. Since the crystalline silicate grains are generally made through high-temperature annealing above 800K from amorphous ones, it is believed that the crystalline silicate grains produced at the inner part of the disk were transported to the outer cold regions where comet nuclei formed. Comet C/2012 S1 (ISON) is a long-period Oort cloud comet, discovered in September 2012. Mid-IR observations of this new comet and investigation of the 10-micron silicate feature help us to understand the formation of crystalline silicate grains in the early solar nebula. In particular, comet ISON is a sungrazing comet, which is predicted to pass close by the Sun and Earth and becoming a bright object. We might expect possible splitting and exposing of pristine materials inside the nucleus after its perihelion passage. If it splits, we can also investigate the homogeneity of the comet nucleus, and can compare the results with ecliptic comets, such as 9P/Temple and 73P/SW. Even if it does not split, we can fully investigate the evolution of crystalline grains described above. Thus, observations both at pre- and post-pelihelion are indespensable. We have a plan to observe the comet ISON with COMICS (Cooled Mid-Infrared Camera and Spectrometer) mounted on the 8.2m Subaru Telescope on late October 2013 and mid-January 2014. Subaru+COMICS in mid-infrared is a powerful tool for spectroscopic observations of cometary silicate grains. COMICS observations occupy an important place among organized many facilities and science of comet observations. We will conduct imaging and low-dispersion spectroscopic observations in mid-infrared region for the comet. We will show the preliminary result of the observations on October

  16. Some Observations on the Current Status of Performing Finite Element Analyses

    NASA Technical Reports Server (NTRS)

    Raju, Ivatury S.; Knight, Norman F., Jr; Shivakumar, Kunigal N.

    2015-01-01

    Aerospace structures are complex high-performance structures. Advances in reliable and efficient computing and modeling tools are enabling analysts to consider complex configurations, build complex finite element models, and perform analysis rapidly. Many of the early career engineers of today are very proficient in the usage of modern computers, computing engines, complex software systems, and visualization tools. These young engineers are becoming increasingly efficient in building complex 3D models of complicated aerospace components. However, the current trends demonstrate blind acceptance of the results of the finite element analysis results. This paper is aimed at raising an awareness of this situation. Examples of the common encounters are presented. To overcome the current trends, some guidelines and suggestions for analysts, senior engineers, and educators are offered.

  17. Initial Checkout Results of the Compact Infrared Camera (circ) for Earth Observation

    NASA Astrophysics Data System (ADS)

    Kato, E.; Katayama, H.; Sakai, M.; Nakajima, Y.; Kimura, T.; Nakau, K.; Tonooka, H.

    2015-04-01

    Compact Infrared Camera (CIRC) is a technology-demonstration instrument equipped with an uncooled infrared array detector (microbolometer) for space application. CIRC is the first microbolometer sensor without a calibration function in orbit, like a shutter system or an onboard blackbody. The main objective of the CIRC is to detect wildfires, which are major and chronic disasters affecting various countries of Southeast Asia, particularly considering the effects of global warming and climate change. The CIRC achieves a small size (approximately 200 mm), light mass (approximately 3 kg), and low electrical power consumption (<20 W) by employing athermal optics and a shutterless system. The CIRC can be consequently mounted on multiple satellites to enable highfrequency observation. Installation of CIRCs on the ALOS-2 and on the JEM/CALET is expected to increase observation frequency. We present the initial check-out results of the CIRC onboard ALOS-2. Since the initial check-out phase (July 4-14, 2014), the CIRC has acquired the images of Earth. CIRC was demonstrated to function according to its intended design. After the early calibration validation phase, which confirmed the temperature accuracy of observed data, CIRC data has been available to the public January 2015 onward. We also introduce a few observational results about wildfire, volcanoes, and heat-island.

  18. AKARI OBSERVATION OF THE FLUCTUATION OF THE NEAR-INFRARED BACKGROUND

    SciTech Connect

    Matsumoto, T.; Seo, H. J.; Lee, H. M.; Jeong, W.-S.; Pyo, J.; Matsuura, S.; Matsuhara, H.; Oyabu, S.; Wada, T.

    2011-12-01

    We report a search for fluctuations of the sky brightness toward the north ecliptic pole with the Japanese infrared astronomical satellite AKARI, at 2.4, 3.2, and 4.1 {mu}m. We obtained circular maps with 10' diameter fields of view, which clearly show a spatial structure on the scale of a few hundred arcseconds. A power spectrum analysis shows that there is a significant excess fluctuation at angular scales larger than 100'' that cannot be explained by zodiacal light, diffuse Galactic light, shot noise of faint galaxies, or clustering of low-redshift galaxies. These results are consistent with observations at 3.6 and 4.5 {mu}m by NASA's Spitzer Space Telescope. The fluctuating component observed at large angular scales has a blue stellar spectrum which is similar to that of the spectrum of the excess isotropic emission observed with the Infrared Telescope in Space. A significant spatial correlation between wavelength bands was found, and the slopes of the linear correlations are consistent with the spectrum of the excess fluctuation. These findings indicate that the detected fluctuation could be attributed to the first stars of the universe, i.e., Population III stars. The observed fluctuation provides an important constraint on the era of the first stars.

  19. Spitzer Observations of Long-term Infrared Variability among Young Stellar Objects in Chamaeleon I

    NASA Astrophysics Data System (ADS)

    Flaherty, Kevin M.; DeMarchi, Lindsay; Muzerolle, James; Balog, Zoltan; Herbst, William; Megeath, S. Thomas; Furlan, Elise; Gutermuth, Robert

    2016-12-01

    Infrared variability is common among young stellar objects, with surveys finding daily to weekly fluctuations of a few tenths of a magnitude. Space-based observations can produce highly sampled infrared light curves, but are often limited to total baselines of about 1 month due to the orientation of the spacecraft. Here we present observations of the Chameleon I cluster, whose low declination makes it observable by the Spitzer Space Telescope over a 200-day period. We observe 30 young stellar objects with a daily cadence to better sample variability on timescales of months. We find that such variability is common, occurring in ˜80% of the detected cluster members. The change in [3.6]-[4.5] color over 200 days for many of the sources falls between that expected for extinction and fluctuations in disk emission. With our high cadence and long baseline we can derive power spectral density curves covering two orders of magnitude in frequency and find significant power at low frequencies, up to the boundaries of our 200-day survey. Such long timescales are difficult to explain with variations driven by the interaction between the disk and stellar magnetic field, which has a dynamical timescale of days to weeks. The most likely explanation is either structural or temperature fluctuations spread throughout the inner ˜0.5 au of the disk, suggesting that the intrinsic dust structure is highly dynamic.

  20. Observations of the Near-infrared Spectrum of the Zodiacal Light with CIBER

    NASA Astrophysics Data System (ADS)

    Tsumura, K.; Battle, J.; Bock, J.; Cooray, A.; Hristov, V.; Keating, B.; Lee, D. H.; Levenson, L. R.; Mason, P.; Matsumoto, T.; Matsuura, S.; Nam, U. W.; Renbarger, T.; Sullivan, I.; Suzuki, K.; Wada, T.; Zemcov, M.

    2010-08-01

    Interplanetary dust (IPD) scatters solar radiation which results in the zodiacal light that dominates the celestial diffuse brightness at optical and near-infrared wavelengths. Both asteroid collisions and cometary ejections produce the IPD, but the relative contribution from these two sources is still unknown. The low resolution spectrometer (LRS) onboard the Cosmic Infrared Background ExpeRiment (CIBER) observed the astrophysical sky spectrum between 0.75 and 2.1 μm over a wide range of ecliptic latitude. The resulting zodiacal light spectrum is redder than the solar spectrum, and shows a broad absorption feature, previously unreported, at approximately 0.9 μm, suggesting the existence of silicates in the IPD material. The spectral shape of the zodiacal light is isotropic at all ecliptic latitudes within the measurement error. The zodiacal light spectrum, including the extended wavelength range to 2.5 μm using Infrared Telescope in Space (IRTS) data, is qualitatively similar to the reflectance of S-type asteroids. This result can be explained by the proximity of S-type asteroidal dust to Earth's orbit, and the relatively high albedo of asteroidal dust compared with cometary dust.

  1. Near-Infrared Observations of Neptune's Tropospheric Cloud Layer with the Lick Observatory Adaptive Optics System

    NASA Astrophysics Data System (ADS)

    Roe, Henry G.; Gavel, Donald; Max, Claire; de Pater, Imke; Gibbard, Seran; Macintosh, Bruce; Baines, Kevin H.

    2001-09-01

    We provide one of the first constraints on the combined infrared single-scattering albedo and opacity of Neptune's upper tropospheric cloud layer. For the observations, we used the adaptive optics system on the Lick Observatory's 3 m Shane Telescope (Mount Hamilton, California). The cloud layer is thought to be composed of H2S and extend up to 3.5-4.5 bars. Previously, the single-scattering albedo was measured in the range 0.2-0.94 μm and found to be extremely high (>0.8), but decreasing with increasing wavelength. Assuming an optically thick cloud, we find the best-fit single-scattering albedo of a 3.5 bar layer to be 0.23+0.07-0.08 at 1.27 μm and 0.18+0.03-0.04 at 1.56 μm. Uncertainties in the column density of haze above the cloud layer, and from deconvolution to remove contaminating light scattered by the point-spread function from infrared-bright features, indicate that the cloud could be even darker, but it is unlikely to be brighter than we report. The cloud particles could be brighter than we report if the total near-infrared opacity of the cloud is very low or the cloud's scattering phase function is significantly more forward-scattering at 1.2-1.6 μm than at 0.75 μm.

  2. OBSERVATIONS OF THE NEAR-INFRARED SPECTRUM OF THE ZODIACAL LIGHT WITH CIBER

    SciTech Connect

    Tsumura, K.; Matsumoto, T.; Matsuura, S.; Wada, T.; Battle, J.; Bock, J.; Zemcov, M.; Cooray, A.; Hristov, V.; Levenson, L. R.; Mason, P.; Sullivan, I.; Keating, B.; Renbarger, T.; Lee, D. H.; Nam, U. W.; Suzuki, K.

    2010-08-10

    Interplanetary dust (IPD) scatters solar radiation which results in the zodiacal light that dominates the celestial diffuse brightness at optical and near-infrared wavelengths. Both asteroid collisions and cometary ejections produce the IPD, but the relative contribution from these two sources is still unknown. The low resolution spectrometer (LRS) onboard the Cosmic Infrared Background ExpeRiment (CIBER) observed the astrophysical sky spectrum between 0.75 and 2.1 {mu}m over a wide range of ecliptic latitude. The resulting zodiacal light spectrum is redder than the solar spectrum, and shows a broad absorption feature, previously unreported, at approximately 0.9 {mu}m, suggesting the existence of silicates in the IPD material. The spectral shape of the zodiacal light is isotropic at all ecliptic latitudes within the measurement error. The zodiacal light spectrum, including the extended wavelength range to 2.5 {mu}m using Infrared Telescope in Space (IRTS) data, is qualitatively similar to the reflectance of S-type asteroids. This result can be explained by the proximity of S-type asteroidal dust to Earth's orbit, and the relatively high albedo of asteroidal dust compared with cometary dust.

  3. Hurricane Ivan as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  4. Hurricane Ivan as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  5. An Overview of Ultraviolet Through Infrared Reflectance Spectroscopic Observations of Mercury During the First MESSENGER Flyby

    NASA Astrophysics Data System (ADS)

    Izenberg, N. R.; McClintock, W. E.; Holsclaw, G. M.; Robinson, M. S.; Blewett, D. T.; Domingue, D. L.; Head, J. W.; Jensen, E. A.; Kochte, M. C.; Lankton, M. R.; Murchie, S. L.; Sprague, A. L.; Vilas, F.; Solomon, S. C.

    2008-05-01

    During the first MESSENGER flyby of Mercury on January 14, 2008, the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) measured reflectance spectra from Mercury's surface over the wavelength range 220-1450 nm. These are the first high-spatial-resolution (<10 km) spectra at any wavelength and the first reported ultraviolet (UV, wavelength < 360 nm) observations of the surface. MASCS observed the sunlit surface for approximately 14 minutes after closest approach, acquiring over 650 spectra with the Visible and Infrared Spectrograph (VIRS) detectors of MASCS sensitive to wavelengths of 350-1450 nm. MASCS also obtained just under four grating scans in the middle ultraviolet (220-320 nm) using MASCS's Ultraviolet and Visible Spectrometer (UVVS) component. Most of the near-equatorial ground track of the observation covered terrain in the previously unseen hemisphere of Mercury but also crossed into the hemisphere viewed by Mariner 10 south of Mozart crater and in Tir Planitia. Ground-based observations of Mercury reveal a surface with a red, nearly featureless spectrum in the visible and near-infrared (wavelengths greater than ~ 500 nm) that has been interpreted as evidence for a largely iron-poor feldspathic composition. Initial analyses of VIRS spectra also show strongly red-sloped, near featureless spectra, appearing to support contentions of low iron abundance in surface materials. However, interpretation of Mercury's spectral reflectance is complicated by our lack of knowledge about the effects on its surface materials of space weathering, which both suppresses the strength of spectral absorption features and reddens the spectrum. Brightness variations and absorption bands in ultraviolet reflectance may help determine both the nature and extent of processes that modify observed reflectance at longer wavelengths. MASCS surface observation data demonstrate spectral variations across the Mercury surface that can be related to previous telescopic

  6. Spitzer IRS Observations of Edge-on Protoplanetary Disks and Infrared Companions

    NASA Astrophysics Data System (ADS)

    Kruger, Andrew J.

    2011-01-01

    Lahuis et al. (2006) showed that Spitzer IRS observations of gas phase molecular absorption toward young stars could be used to determine physical conditions within a few AU of the star. The pencil beam nature of this method requires an edge-on disk geometry with a large column between the observer and the emitting source. Molecular gas absorption has also been detected towards GV Tau N, a classical infrared companion (Koresko et al. 1997) that is likely a circumstellar disk seen near edge-on (Correia et al. 2007). We were granted time with Spitzer IRS to obtain high signal-to-noise spectra of 7 YSOs, three classified as disks seen near edge-on and four classical IRCs, to search for molecular absorption. We present findings from this Spitzer IRS project, along with near-infrared spectroscopy of CO fundamental transitions and mid-infrared imaging. We find that although DG Tau B shows CO2 gas absorption at a temperature similar to IRS 46 and GV Tau N, it likely originates from a moderately different region of the disk, indicating that the detection of organic molecules, even in edge-on disks, is highly sensitive to the line of sight. We further find DG Tau B likely displays high amounts of dust grain growth and settling, and we provide support for the VV CrA binary disk geometry where the absorption seen towards the IRC is due to the disk around the Primary being in the line of sight (Smith et al. 2009). This work is supported by NSF grant AST-0708074 and NASA support for Spitzer observations through contract RSA No. 1346810, issued by JPL.

  7. Upcoming and Future Missions in the Area of Infrared Astronomy: Spacecraft and Ground-based Observations

    NASA Technical Reports Server (NTRS)

    Sittler, E. C., Jr.

    2004-01-01

    The IRIS instrument on the Voyager spacecrafts made major discoveries with regard to the giant planets, their moons and rings and paved the way for future infrared observations for planetary missions within our solar system. The CIRS instrument of Cassini with much greater spectral-spatial resolution and sensitivity than that provided by IRIS is now rapidly approaching the Saturnian system with orbit insertion on July 1, 2004, for which CIRS is expected to provide an order of magnitude advance beyond that provided by IRIS. The Mars program is also presently dominated by infrared observations in the near to mid-infrared spectral bands for missions such as Mars Global Surveyor and its TES instrument and Odyssey with its THEMIS instrument. In the case of Earth science we have such missions as TIMED, which makes infrared observations of the thermosphere using the SABER instrument. With the newly formed New Frontiers Program we have the opportunity for $650M missions such as Kuiper Belt-Pluto Explorer and Jupiter Polar Orbiter with Probes. Under the Flagship line, once per decade, we have the opportunity for $1B missions for which Europa is presently being considered; for this mission infrared measurements could look for hot spots within the maze of cracks and faults on Europa s surface. On Kuiper Belt- Pluto there is an imaging near-IR spectrometer called LEISA. Another mission on the horizon is Titan Orbiter Aerorover Mission (TOAM) for which there is planned a state-of-art version of CIRS called TIRS on the orbiter that will map out the atmospheric composition with unprecedented wavelength coverage and spectral-spatial resolution. This instrument will also provide temperature maps of the surface of Titan to look for hot spots where life may form. On the same mission there will be a descent imager on the Aerorover (i.e., balloon) similar to that provided by LEISA on the Pluto mission to provide compositional-topographical maps of Titan s surface. Other future mission

  8. Observation and Modeling of the SVdiff-SHdiff splitting induced by elastic anisotropy and finite-frequency effects in D"

    NASA Astrophysics Data System (ADS)

    Hung, S. H.; Liao, T. Y.; Sales de Andrade, E.; Liu, Q.

    2014-12-01

    The existence of seismic anisotropy in D" has been diagnosed by the evident arrival-time shifts between SVdiff and SHdiff phases and discrepancies in SKS and SKKS splitting. Previous numerical modeling of seismic wave propagation demonstrates that the SVdiff and SHdiff arrivals are not synchronized in time even in an isotropic Earth model due to intrinsically different finite-frequency sensitivity of non-geometrical diffracted S waves between radial and transverse components. Therefore, prior to using diffracted shear wave phases to constrain seismic anisotropy in the lowermost mantle, we need to first clarify the finite-frequency effects of diffracted shear waves propagating through D" velocity heterogeneity. In this study, we collect broadband waveforms from intermediate and deep-focus earthquakes (> 150 km) with epicentral distances of 90-145o and magnitudes greater than 5.8 during 1997-2012. The splitting between the vertically (SV) and transversely (SH) polarized arrivals of S(diff) phases after correcting for upper mantle anisotropy are analyzed to investigate seismic anisotropy in D" induced by anisotropic material elasticity and finite-frequency wave propagation effects. Both positive and negative SVdiff-SHdiff split times are observed in seismically slow regions; however, the proposed viable scenario in which partial melts produced at the base of the hot mantle plumes have been aligned laterally in D" by the basal boundary flow can only explain relatively earlier SHdiff arrivals. Positive SV-SH times (i.e., SH traveling faster) found in high-velocity regions are consistent with the consequences caused by intrinsic LPO of pPv-MgSiO3 in horizontally-lying slabs and different finite-frequency sensitivity between SVdiff and SHdiff in the heterogeneous lowermost mantle. We will differentiate and quantify these two effects on the observed Sdiff splitting through simulating ground-truth finite-frequency shear wave diffraction in the 3-D tomography Earth model and

  9. 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.

  10. 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.

  11. X-RAY, OPTICAL, AND INFRARED OBSERVATIONS OF GX 339-4 DURING ITS 2011 DECAY

    SciTech Connect

    Dincer, Tolga; Kalemci, Emrah; Buxton, Michelle M.; Bailyn, Charles D.; Tomsick, John A.; Corbel, Stephane

    2012-07-01

    We report multiwavelength observations of the black hole transient GX 339-4 during its outburst decay in 2011 using the data from RXTE, Swift, and SMARTS. Based on the X-ray spectral, temporal, and optical and infrared (OIR) properties, the source evolved from the soft intermediate to the hard state. Twelve days after the start of the transition toward the hard state, a rebrightening was observed simultaneously in the optical and the infrared bands. Spectral energy distributions (SEDs) were created from observations at the start, and close to the peak of the rebrightening. The excess OIR emission above the smooth exponential decay yields flat spectral slopes for these SEDs. Assuming that the excess is from a compact jet, we discuss the possible locations of the spectral break that mark the transition from optically thick to optically thin synchrotron components. Only during the rising part of the rebrightening, we detected fluctuations with the binary period of the system. We discuss a scenario that includes irradiation of the disk in the intermediate state, irradiation of the secondary star during OIR rise, and jet emission dominating during the peak to explain the entire evolution of the OIR light curve.

  12. Simultaneous infrared and optical observations of the transiting debris cloud around WD 1145+017

    NASA Astrophysics Data System (ADS)

    Zhou, G.; Kedziora-Chudczer, L.; Bailey, J.; Marshall, J. P.; Bayliss, D. D. R.; Stockdale, C.; Nelson, P.; Tan, T. G.; Rodriguez, J. E.; Tinney, C. G.; Dragomir, D.; Colon, K.; Shporer, A.; Bento, J.; Sefako, R.; Horne, K.; Cochran, W.

    2016-12-01

    We present multiwavelength photometric monitoring of WD 1145+017, a white dwarf exhibiting periodic dimming events interpreted to be the transits of orbiting, disintegrating planetesimals. Our observations include the first set of near-infrared light curves for the object, obtained on multiple nights over the span of 1 month, and recorded multiple transit events with depths varying between ˜20 and 50 per cent. Simultaneous near-infrared and optical observations of the deepest and longest duration transit event were obtained on two epochs with the Anglo-Australian Telescope and three optical facilities, over the wavelength range of 0.5-1.2 μm. These observations revealed no measurable difference in transit depths for multiple photometric pass bands, allowing us to place a 2σ lower limit of 0.8 μm on the grain size in the putative transiting debris cloud. This conclusion is consistent with the spectral energy distribution of the system, which can be fit with an optically thin debris disc with minimum particle sizes of 10^{+5}_{-3} μm.

  13. Hurricane Frances as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS) and SeaWinds

    NASA Technical Reports Server (NTRS)

    2004-01-01

    this combination image, the AIRS infrared data reveals the temperature of the atmosphere around the storm, but doesn't tell us about the wind direction or relative intensity. The directional vectors of the SeaWinds data set show how the air is circulating around the storm.

    Scatterometers measure surface wind speed and direction by bouncing microwave pulses off the ocean's surface. The SeaWinds instruments measure the backscattered radar energy from wind-generated ocean waves. By making multiple measurements from different looks at the same location, we can infer the vector wind averaged over each 25 km resolution cell. The primary mission objective of the SeaWinds and QuikSCAT scatterometers is to obtain long-term, global coverage of the ocean vector winds for oceanographic and climate research. While not specifically designed for detailed mapping and tracking of hurricanes, both instruments have been found to be useful resources for operational forecasters.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  14. Hurricane Frances as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS) and SeaWinds

    NASA Technical Reports Server (NTRS)

    2004-01-01

    this combination image, the AIRS infrared data reveals the temperature of the atmosphere around the storm, but doesn't tell us about the wind direction or relative intensity. The directional vectors of the SeaWinds data set show how the air is circulating around the storm.

    Scatterometers measure surface wind speed and direction by bouncing microwave pulses off the ocean's surface. The SeaWinds instruments measure the backscattered radar energy from wind-generated ocean waves. By making multiple measurements from different looks at the same location, we can infer the vector wind averaged over each 25 km resolution cell. The primary mission objective of the SeaWinds and QuikSCAT scatterometers is to obtain long-term, global coverage of the ocean vector winds for oceanographic and climate research. While not specifically designed for detailed mapping and tracking of hurricanes, both instruments have been found to be useful resources for operational forecasters.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  15. Hurricane Alex as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Carolina, traveling northeast at 6 mph.

    [figure removed for brevity, see original site] August 1, 2004, 1:30am ET Daylight snapshot from AIRS visible/near-infrared. At the time AIRS made this observation, Alex was still a tropical depression and just getting organized.

    Movies Slice down the atmosphere with the AIRS infrared sensor.

    [figure removed for brevity, see original site] August 3, 2004, 1:30am ET Alex becomes the first hurricane of the 2004 North Atlantic season with sustained winds at 75 mph.

    [figure removed for brevity, see original site] August 2, 2004, 1:30pm ET Alex is located about 120 miles southeast of Charleston, South Carolina. Alex has now begun to move to the northeast and a general northeastward track is expected the next couple of days with a gradual acceleration in forward speed as it begins to interact with stronger upper level winds.

    [figure removed for brevity, see original site] August 2, 2004, 1:30am ET Alex now has sustained winds of 35 knots.

    [figure removed for brevity, see original site] August 1, 2004, 1:30pm ET Alex is tropical depression and beginning to get organized.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  16. Hurricane Alex as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Carolina, traveling northeast at 6 mph.

    [figure removed for brevity, see original site] August 1, 2004, 1:30am ET Daylight snapshot from AIRS visible/near-infrared. At the time AIRS made this observation, Alex was still a tropical depression and just getting organized.

    Movies Slice down the atmosphere with the AIRS infrared sensor.

    [figure removed for brevity, see original site] August 3, 2004, 1:30am ET Alex becomes the first hurricane of the 2004 North Atlantic season with sustained winds at 75 mph.

    [figure removed for brevity, see original site] August 2, 2004, 1:30pm ET Alex is located about 120 miles southeast of Charleston, South Carolina. Alex has now begun to move to the northeast and a general northeastward track is expected the next couple of days with a gradual acceleration in forward speed as it begins to interact with stronger upper level winds.

    [figure removed for brevity, see original site] August 2, 2004, 1:30am ET Alex now has sustained winds of 35 knots.

    [figure removed for brevity, see original site] August 1, 2004, 1:30pm ET Alex is tropical depression and beginning to get organized.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  17. Preliminary Results from the MSX Satellite: Infrared Observations of the Galactic Plane

    NASA Astrophysics Data System (ADS)

    Shipman, R. F.; Egan, M. P.; Price, S. D.

    1996-12-01

    We present preliminary results from observations of two regions in the Galactic plane from the mid-infrared radiometer aboard the Midcource Space Experiment (MSX). The observations cover a {1(deg) x 3(deg}) field of the Galactic center and a similar field at {l=28(deg}) . The radiometer abord MSX simultaneously observes 5 pass bands ranging from 4 to 25 {microns } with a spatial resolution of 18" . We present results for the MSX Band A detectors (6-11 \\: microns ) and compare the results with IRAS 12 \\: microns ISSA images and full resolution IRAS images from the Galactic Plane Supplement (GPS). The higher resolution of MSX clearly resolves the regions that were confused to IRAS. We compare the extracted source density as a function of galatic lattitude with current IRAS data and models.

  18. Infrared observations of the dark matter lens candidate Q2345+007

    NASA Technical Reports Server (NTRS)

    Mcleod, Brian; Rieke, Marcia; Weedman, Daniel

    1994-01-01

    Deep K-band observations are presented of the double image quasar Q2345+007. This has the largest separation (7.1 sec) of any quasar image pair considered as gravitationally lensed, so the required lens is massive (10(exp 13) solar masses). No lens has been detected in previous deep images at visible wavelengths, and we find no lens to limiting K magnitude 20.0 in the infrared image. This constrains any lens to being much less luminous than brightest cluster galaxies, while the lens must be much more massive than such galaxies to produce the observed separation. Because spectral data indicate exceptional intrinsic similarity in the quasar image components, this pair remains as the most intriguing example of an observed configuration requiring the presence of massive, concentrated dark matter acting as a gravitational lens.

  19. Infrared observations of the dark matter lens candidate Q2345+007

    NASA Technical Reports Server (NTRS)

    Mcleod, Brian; Rieke, Marcia; Weedman, Daniel

    1994-01-01

    Deep K-band observations are presented of the double image quasar Q2345+007. This has the largest separation (7.1 sec) of any quasar image pair considered as gravitationally lensed, so the required lens is massive (10(exp 13) solar masses). No lens has been detected in previous deep images at visible wavelengths, and we find no lens to limiting K magnitude 20.0 in the infrared image. This constrains any lens to being much less luminous than brightest cluster galaxies, while the lens must be much more massive than such galaxies to produce the observed separation. Because spectral data indicate exceptional intrinsic similarity in the quasar image components, this pair remains as the most intriguing example of an observed configuration requiring the presence of massive, concentrated dark matter acting as a gravitational lens.

  20. High spectral resolution observations of Martian atmosphere in infrared - submillimeter range from ground-based instruments.

    NASA Astrophysics Data System (ADS)

    Nakagawa, Hiromu; Kasaba, Yasumasa; Aoki, Shohei; Murata, Isao; Maezawa, Hiroyuki; Okano, Shoichi; Sagawa, Hideo; Kasai, Yasuko

    2010-05-01

    With increased knowledge on our "neighbor" planets Mars and Venus, based on recent aggressive explorations by the US and Europe, our image on them is changing significantly. In particular, Mars is called ‘a frozen water planet'. It is almost certain that Mars once had duration with warm and wet climate [Head et al., 1999; Donahue, 1995; Parker et al., 1993]. It still conserves a large amount of water ice under the surface [Boynton et al., 2002; Mitrofanov et al., 2002; Feldman et al., 2002]. The question "Why and when did they diverge?" is essential for their environments which potentially could create and keep the life or not. Many molecules in planetary atmospheres show transitions in the mid infrared - submillimeter region. Thus, high-resolution spectroscopy in this region is significantly indispensable to study planetary atmospheres. We searched sulfur oxide (SO2 and SO) in the Martian atmosphere by the Atacama Submillimeter Telescope Experiment (ASTE). Sulfur oxide is one of the most evident species in terrestrial volcanic gases. Although it has not yet been detected at Mars, this detection can constraint the Martian crustal and volcanic activities. We observed northern winter of Mars on 26/Dec./2007 (Ls=8.1) in 346 GHz range with ~ 1h integration, and got the upper limit of the SO2 mixing ratio, 2 ppb. We concluded that the crustal or volcanic gas produced into the atmosphere is tenuous in northern winter [Nakagawa et al., 2009]. Infrared heterodyne spectroscopy has proven to be a powerful tool for astrophysical studies. To achieve highest spectral resolution and sensitivity as well as compact instrumentation heterodyne systems are advantageous over direct-detection methods. Our group in Tohoku University has developed own heterodyne system for infrared spectrometer for Earth's atmosphere over the past 20 years. The failure of earlier attempts to build tunable systems using tunable diode lasers was due mostly to insufficient laser power. Recently, quantum

  1. 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.

  2. 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.

  3. A New Finite-Time Observer for Nonlinear Systems: Applications to Synchronization of Lorenz-Like Systems

    PubMed Central

    Aguilar-López, Ricardo

    2016-01-01

    This paper proposes a synchronization methodology of two chaotic oscillators under the framework of identical synchronization and master-slave configuration. The proposed methodology is based on state observer design under the frame of control theory; the observer structure provides finite-time synchronization convergence by cancelling the upper bounds of the main nonlinearities of the chaotic oscillator. The above is showed via an analysis of the dynamic of the so called synchronization error. Numerical experiments corroborate the satisfactory results of the proposed scheme. PMID:27738651

  4. A New Finite-Time Observer for Nonlinear Systems: Applications to Synchronization of Lorenz-Like Systems.

    PubMed

    Aguilar-López, Ricardo; Mata-Machuca, Juan L

    2016-01-01

    This paper proposes a synchronization methodology of two chaotic oscillators under the framework of identical synchronization and master-slave configuration. The proposed methodology is based on state observer design under the frame of control theory; the observer structure provides finite-time synchronization convergence by cancelling the upper bounds of the main nonlinearities of the chaotic oscillator. The above is showed via an analysis of the dynamic of the so called synchronization error. Numerical experiments corroborate the satisfactory results of the proposed scheme.

  5. Mid-infrared Spectroscopic Observations of the Dust-forming Classical Nova V2676 Oph

    NASA Astrophysics Data System (ADS)

    Kawakita, Hideyo; Ootsubo, Takafumi; Arai, Akira; Shinnaka, Yoshiharu; Nagashima, Masayoshi

    2017-02-01

    The dust-forming nova V2676 Oph is unique in that it was the first nova to provide evidence of C2 and CN molecules during its near-maximum phase and evidence of CO molecules during its early decline phase. Observations of this nova have revealed the slow evolution of its lightcurves and have also shown low isotopic ratios of carbon (12C/13C) and nitrogen (14N/15N) in its envelope. These behaviors indicate that the white dwarf (WD) star hosting V2676 Oph is a CO-rich WD rather than an ONe-rich WD (typically larger in mass than the former). We performed mid-infrared spectroscopic and photometric observations of V2676 Oph in 2013 and 2014 (respectively 452 and 782 days after its discovery). No significant [Ne ii] emission at 12.8 μm was detected at either epoch. These provided evidence for a CO-rich WD star hosting V2676 Oph. Both carbon-rich and oxygen-rich grains were detected in addition to an unidentified infrared feature at 11.4 μm originating from polycyclic aromatic hydrocarbon molecules or hydrogenated amorphous carbon grains in the envelope of V2676 Oph. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  6. Space-based infrared scanning sensor LOS determination and calibration using star observation

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Xu, Zhan; An, Wei; Deng, Xin-Pu; Yang, Jun-Gang

    2015-10-01

    This paper provides a novel methodology for removing sensor bias from a space based infrared (IR) system (SBIRS) through the use of stars detected in the background field of the sensor. Space based IR system uses the LOS (line of sight) of target for target location. LOS determination and calibration is the key precondition of accurate location and tracking of targets in Space based IR system and the LOS calibration of scanning sensor is one of the difficulties. The subsequent changes of sensor bias are not been taking into account in the conventional LOS determination and calibration process. Based on the analysis of the imaging process of scanning sensor, a theoretical model based on the estimation of bias angles using star observation is proposed. By establishing the process model of the bias angles and the observation model of stars, using an extended Kalman filter (EKF) to estimate the bias angles, and then calibrating the sensor LOS. Time domain simulations results indicate that the proposed method has a high precision and smooth performance for sensor LOS determination and calibration. The timeliness and precision of target tracking process in the space based infrared (IR) tracking system could be met with the proposed algorithm.

  7. An x-ray study of luminous infrared galaxies observed with ASCA

    NASA Astrophysics Data System (ADS)

    Misaki, K.; Iwasawa, K.; Taniguchi, Y.; Terashima, Y.; Kunieda, H.; Watarai, H.

    The discovery of ultra-luminous infrared galaxies (ULIRGs) has provided a clue to an evolutionary connection between starburst and active galactic nuclei. The IRAS color is suggested to be a possible trace of the evolution. We present the results of ASCA observations of two ULIRGs, IRAS20551-4250 and IRAS23128-5919, which are southern 100 μm bright galaxies with LIR ~ 1012Lsolar. Both are mergers and have a ``warm'' IRAS color (25μm100μm >= 0.15). The ASCA spectrum of IRAS20551-4250 can be characterized by two components, one of which is a soft thermal component (kT ~ 0.3keV) and the other is a hard power-law component absorbed by a column density of 1022 cm-2. The observed X-ray luminosity is ~ 2.5 × 1042 ergs/s in the rest frame 2-10keV band (assuming H0 = 50 km/s/Mpc). IRAS23128-5919 also shows a hard spectrum (LX ~ 3 × 1042 ergs/s), but thermal emission is not as clear as that in IRAS20551-4250. Since these targets are similar in infrared luminosity as well as in hard X-rays but not in soft X-rays, LIR would be associated with hard X-rays. In addition to these results, we here compare X-ray properties of ULIRGs with IR properties.

  8. Characterizing ultraviolet and infrared observational properties for galaxies. II. Features of attenuation law

    SciTech Connect

    Mao, Ye-Wei; Kong, Xu; Lin, Lin E-mail: xkong@ustc.edu.cn

    2014-07-01

    Variations in the attenuation law have a significant impact on observed spectral energy distributions for galaxies. As one important observational property for galaxies at ultraviolet and infrared wavelength bands, the correlation between infrared-to-ultraviolet luminosity ratio and ultraviolet color index (or ultraviolet spectral slope), i.e., the IRX-UV relation (or IRX-β relation), offered a widely used formula for correcting dust attenuation in galaxies, but the usability appears to be in doubt now because of considerable dispersion in this relation found by many studies. In this paper, on the basis of spectral synthesis modeling and spatially resolved measurements of four nearby spiral galaxies, we provide an interpretation of the deviation in the IRX-UV relation with variations in the attenuation law. From both theoretical and observational viewpoints, two components in the attenuation curve, the linear background and the 2175 Å bump, are suggested to be the parameters in addition to the stellar population age (addressed in the first paper of this series) in the IRX-UV function; different features in the attenuation curve are diagnosed for the galaxies in our sample. Nevertheless, it is often difficult to ascertain the attenuation law for galaxies in actual observations. Possible reasons for preventing the successful detection of the parameters in the attenuation curve are also discussed in this paper, including the degeneracy of the linear background and the 2175 Å bump in observational channels, the requirement for young and dust-rich systems to study, and the difficulty in accurate estimates of dust attenuations at different wavelength bands.

  9. Sea Ice and Ice Temperature Variability as Observed by Microwave and Infrared Satellite Data

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Recent reports of a retreating and thinning sea ice cover in the Arctic have pointed to a strong suggestion of significant warming in the polar regions. It is especially important to understand what these reports mean in light of the observed global warning and because the polar regions are expected to be most sensitive to changes in climate. To gain insight into this phenomenon, co-registered ice concentrations and surface temperatures derived from two decades of satellite microwave and infrared data have been processed and analyzed. While observations from meteorological stations indicate consistent surface warming in both regions during the last fifty years, the last 20 years of the same data set show warming in the Arctic but a slight cooling in the Antarctic. These results are consistent with the retreat in the Arctic ice cover and the advance in the Antarctic ice cover as revealed by historical satellite passive microwave data. Surface temperatures derived from satellite infrared data are shown to be consistent within 3 K with surface temperature data from the limited number of stations. While not as accurate, the former provides spatially detailed changes over the twenty year period. In the Arctic, for example, much of the warming occurred in the Beaufort Sea and the North American region in 1998 while slight cooling actually happened in parts of the Laptev Sea and Northern Siberia during the same time period. Big warming anomalies are also observed during the last five years but a periodic cycle of about ten years is apparent suggesting a possible influence of the North Atlantic Oscillation. In the Antarctic, large interannual and seasonal changes are also observed in the circumpolar ice cover with regional changes showing good coherence with surface temperature anomalies. However, a mode 3 is observed to be more dominant than the mode 2 wave reported in the literature. Some of these spatial and temporal changes appear to be influenced by the Antarctic

  10. Sea Ice and Ice Temperature Variability as Observed by Microwave and Infrared Satellite Data

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Recent reports of a retreating and thinning sea ice cover in the Arctic have pointed to a strong suggestion of significant warming in the polar regions. It is especially important to understand what these reports mean in light of the observed global warning and because the polar regions are expected to be most sensitive to changes in climate. To gain insight into this phenomenon, co-registered ice concentrations and surface temperatures derived from two decades of satellite microwave and infrared data have been processed and analyzed. While observations from meteorological stations indicate consistent surface warming in both regions during the last fifty years, the last 20 years of the same data set show warming in the Arctic but a slight cooling in the Antarctic. These results are consistent with the retreat in the Arctic ice cover and the advance in the Antarctic ice cover as revealed by historical satellite passive microwave data. Surface temperatures derived from satellite infrared data are shown to be consistent within 3 K with surface temperature data from the limited number of stations. While not as accurate, the former provides spatially detailed changes over the twenty year period. In the Arctic, for example, much of the warming occurred in the Beaufort Sea and the North American region in 1998 while slight cooling actually happened in parts of the Laptev Sea and Northern Siberia during the same time period. Big warming anomalies are also observed during the last five years but a periodic cycle of about ten years is apparent suggesting a possible influence of the North Atlantic Oscillation. In the Antarctic, large interannual and seasonal changes are also observed in the circumpolar ice cover with regional changes showing good coherence with surface temperature anomalies. However, a mode 3 is observed to be more dominant than the mode 2 wave reported in the literature. Some of these spatial and temporal changes appear to be influenced by the Antarctic

  11. Optical and Near Infrared Spectrophotometric Observations of Comet Hale-Bopp

    NASA Astrophysics Data System (ADS)

    Harker, D. E.; Woodward, C. E.; Gehrz, R. D.; Lyke, J.; Saxton, R. M.; McMurtry, C. W.; Rudy, R. J.

    1996-12-01

    Infrared imaging and spectrophotometric studies of transient activity in comets near perihelion passage can provide important information about the physical properties of comet nuclei, including the dust mass loss rate, the morphology of the dust coma, and the nature of short-term outbursts. The dependence of comet activity with heliocentric distance may be affected by many variables such as the surface state of the nucleus, the composition of the nucleus, the rotation rate of the nucleus, the location of active areas on the surface of the nucleus, and the response of the nucleus to solar heating. Variable jet activity may cause fluctuations in the size distribution of the dust that produce observable changes in the color, polarization, superheat, and silicate emission (e.g., Woodward et al. 1997; Gehrz and Ney 1992). We present here preliminary results of our coordinated optical/infrared imaging and infrared spectroscopic monitoring of Comet Hale-Bopp during pre-perihelion passage. Near-infrared spectra obtained in 1996 June are generally featureless and can be fit with a blackbody continuum with a temperature of ~ 5000 K. Imaging observations taken in September of 1996 (heliocentric distance=2.91 AU) indicate an increase in activity of the comet nucleus with the appearance of numerous anti-sunward jets as compared to May 1996 data (heliocentric distance=4.25 AU) . These broadband JHK images (2(') x 2(') field of view) show at least 5 jets fanning out from the nucleus. Cuts along these jets reveal that the surface brightness is falling off as r(-1) as predicted by standard models (Gehrz and Ney 1992). We will also present larger field of view (6(') 4.5(') ) optical images (UBVRI) taken during the same period that detail the extended morphology of the comet tails. References Gehrz,R.D. and E.P. Ney, 1992, Icarus 100,162-186. Woodward,C.E., Shure, M.A., Forrest, W.J., Jones, T.J., Gehrz, R.D., & Nagata, T. 1996, Icarus, 124, in press. Acknowledgments Lyke and Saxton

  12. Infrared observations of the X-ray quasars 0241+622 and MR2251-178

    NASA Technical Reports Server (NTRS)

    Soifer, B. T.; Neugebauer, G.; Matthews, K.

    1979-01-01

    Infrared observations of the recently discovered X-ray quasars 0241+622 and MR2251-178 are reported. Broadband photometry of both quasars was conducted in the 1.25 to 20 micron range and spectrophotometry of 0241+622 was carried out from 1.5 to 2.5 microns. The IR energy distributions of 0241+622, MR2251-178 and the X-ray quasar 3C273 are presented, noting that for wavelengths less than 10 microns, the energy distributions of all three quasars are similar and cannot be distinguished from those of other low redshift quasars. The observed IR, visual and X-ray luminosities of the three quasars are compared and are found not to be strongly correlated. It is remarked, however, that the three X-ray quasars are the brightest known quasars at IR and visual wavelengths, which supports the suggestion that all quasars are bright X-ray emitters.

  13. Infrared Spectrum of the CS_2 Tetramer: Observation of a Structure with D_{2d} Symmetry

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; Oliaee, J. Norooz; Moazzen-Ahmadi, N.; McKellar, A. R. W.

    2013-06-01

    Infrared spectra of carbon disulphide clusters are studied in the region of the CS_2 ν_3 fundamental band (˜1535 cm^{-1}), using a tuneable diode laser to probe a pulsed supersonic slit jet expansion. A symmetric rotor parallel band at 1551.438 cm^{-1} is assigned to CS_2 tetramer. The likely structure is a staggered and tilted barrel with D_{2d} symmetry, similar to the previously observed oblate tetramer of nitrous oxide, in reasonable agreement with that calculated from an empirical CS_2 intermolecular potential function. This is the first high-resolution spectroscopic detection of CS_2 tetramer, and the calculations suggest that there could be other lower energy isomers of (CS_2)_4 which are not yet observed.

  14. Infrared spectrum of the CS2 tetramer: Observation of a structure with D2d symmetry

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; Norooz Oliaee, J.; Moazzen-Ahmadi, N.; McKellar, A. R. W.

    2013-05-01

    Infrared spectra of carbon disulfide clusters are studied in the region of the CS2 ν3 fundamental band (≈1535 cm-1), using a tuneable diode laser to probe a pulsed supersonic slit jet expansion. A symmetric rotor parallel band at 1551.438 cm-1 is assigned to CS2 tetramer. The likely structure is a staggered and tilted barrel with D2d symmetry, similar to the previously observed oblate tetramer of nitrous oxide, and in reasonable agreement with that calculated from an empirical CS2 intermolecular potential function. This is the first high-resolution spectroscopic detection of CS2 tetramer, and the calculations suggest that there could be other low energy isomers of (CS2)4 which are not yet observed.

  15. Autonomous Observing and Control Systems for PAIRITEL, a 1.3m Infrared Imaging Telescope

    NASA Astrophysics Data System (ADS)

    Bloom, J. S.; Starr, D. L.; Blake, C. H.; Skrutskie, M. F.; Falco, E. E.

    2006-07-01

    The Peters Automated Infrared Imaging Telescope (PAIRITEL) is the first meter-class telescope operating as a fully robotic IR imaging system. Dedicated in October 2004, PAIRITEL began regular observations in mid-December 2004 as part of a 1.5 year commissioning period. The system was designed to respond without human intervention to new gamma-ray burst transients: this milestone was finally reached on November 9, 2005 but the telescope had a number of semi-automated sub-10 minute responses throughout early commissioning. When not operating in Target of Opportunity mode, PAIRITEL performs a number of queue scheduled transient monitoring campaigns. To achieve this level of automation, we have developed communicating tools to connect the various sub-systems: an intelligent queue scheduling database, run-time configurable observation sequence software, a data reduction pipeline, and a master state machine which monitors and controls all functions within and affecting the observatory.

  16. Observations with Near Infrared Spectrometer for Hayabusa Mission in the Cruising Phase

    NASA Technical Reports Server (NTRS)

    Abe, M.; Takagi, Y.; Kitazato, K.; Hiroi, T.; Abe, S.; Vilas, F.; Clark, B. E.; Fujiwara, A.

    2005-01-01

    NIRS is a near infrared spectrometer on-board the spacecraft HAYABUSA, which aims to return samples from a near-earth asteroid, 25143 Itokawa. HAYABUSA was successfully launched by Japanese M-V-5 rocket on May 9, 2003. After the successful earth swing-by on May 19, 2004, the spacecraft is now on the way toward the asteroid, where it will arrive in this summer. During the rendezvous phase with the asteroid, we will observe the asteroid surface using NIRS and obtain reflectance spectra of the surface materials across the wavelength range of 850nm to 2100nm. Based on ground-based observations [1],[2],[3], 25143 Itokawa appears to be an S(IV) type asteroid. NIRS can detect absorption bands due to olivine and pyroxene and investigate the mineralogical composition of the surface materials, and reveal a relationship between asteroids and meteorites.

  17. REANALYSIS OF THE NEAR-INFRARED EXTRAGALACTIC BACKGROUND LIGHT BASED ON THE IRTS OBSERVATIONS

    SciTech Connect

    Matsumoto, T.; Kim, M. G.; Pyo, J.; Tsumura, K.

    2015-07-01

    We reanalyze data of the near-infrared background taken by IRTS using up-to-date observational results of zodiacal light (ZL), integrated star light, and diffuse Galactic light. We confirm the existence of residual isotropic emission, which is slightly lower but almost the same as previously reported. At wavelengths longer than 2 μm, the result is fairly consistent with the recent observation with AKARI. We also perform the same analysis using a different ZL model by Wright and detect residual isotropic emission that is slightly lower than that based on the original Kelsall model. Both models show residual isotropic emission that is significantly brighter than the integrated light of galaxies.

  18. Multi-wavelength Observations of Fast Infrared Flares from V404 Cygni in 2015

    NASA Astrophysics Data System (ADS)

    Dallilar, Yigit; Casella, Piergiorgio; Marsh, Tom; Gandhi, Poshak; Fender, Rob; Littlefair, Stuart; Eikenberry, Steve; Garner, Alan; Stelter, Deno; Dhillon, Vik; Mooley, Kunal

    2016-07-01

    We used the fast photometry mode of our new Canarias InfraRed Camera Experiment (CIRCE) on the 10.4-meter Gran Telescopio Canarias to observe V404 Cyg, a stellar mass black hole binary, on June 25, 2015 during its 2015 outburst. CIRCE provided 10Hz sampling in the Ks-band (2.2 microns) In addition, we obtained simultaneous multi wavelength data from our collaborators: three GHz radio bands from the AMI telescope and three optical/UV bands (u', g', r') from ULTRACAM on the William Herschel 4.2-meter telescope. We identify fast (1-second) IR flares with optical counterparts of varying strength/color, which we argue arise from a relativistic jet outflow. These observations provide important constraints on the emission processes and physical conditions in the jet forming region in V404 Cygni. We will discuss these results as well as their implications for relativistic jet formation around stellar-mass black holes.

  19. Multi-wavelength Observations of Fast Infrared Flares from V404 Cygni in 2015

    NASA Astrophysics Data System (ADS)

    Eikenberry, Stephen S.; Dallilar, Yigit; Garner, Alan; Deno Stelter, R.; Gandhi, Poshak; Dhillon, Vik; Littlefair, Stuart; Marsh, Thomas; Fender, Rob P.; Mooley, Kunal

    2016-04-01

    We used the fast photometry mode of our new Canarias InfraRed Camera Experiment (CIRCE) on the 10.4-meter Gran Telescopio Canarias to observe V404 Cyg, a stellar mass black hole binary, on June 25, 2015 during its 2015 outburst. CIRCE provided 10Hz sampling in the Ks-band (2.2 microns) In addition, we obtained simultaneous multi wavelength data from our collaborators: three GHz radio bands from the AMI telescope and three optical/UV bands (u', g', r') from ULTRACAM on the William Herschel 4.2-meter telescope. We identify fast (1-second) IR flares with optical counterparts of varying strength/color, which we argue arise from a relativistic jet outflow. These observations provide important constraints on the emission processes and physical conditions in the jet forming region in V404 Cygni. We will discuss these results as well as their implications for relativistic jet formation around stellar-mass black holes.

  20. Ultraviolet, optical, and infrared observations of the intermediate polar TV Columbae

    NASA Technical Reports Server (NTRS)

    Mateo, M.; Szkody, P.; Hutchings, J.

    1985-01-01

    Forty-three IUE spectra of the X-ray discovered, triply periodic cataclysmic variable, TV Col are examined. The results show that the UV flux varies with the four-day period discovered by Motch in 1981. By fitting continuum models to the UV and optical fluxes, it is inferred that this modulation corresponds to the periodic heating of a normally 9000 K source within the binary system due to reprocessing of beamed X-ray and (possibly) EUV radiation from the vicinity of the degenerate star. The observed flux from this heated source is consistent with its origin at either the disk hot spot or the secondary star. Phasing arguments, however, favor the identification of the latter as the primary reprocessing site in the system. The infrared observations are not consistent with the model proposed by Watts et al. in 1982 and imply that the four-day period does not correspond to the orbital period of the binary.

  1. Multi-Wavelength Near Infrared Observations of Marum and Yasur Volcanoes, Vanuatu

    NASA Astrophysics Data System (ADS)

    Howell, Robert R.; Radebaugh, Jani; Lopes, Rosaly M.; Lorenz, Ralph D.; Turtle, Elizabeth P.

    2014-11-01

    To help understand and test models of thermal emission from planetary volcanoes, we obtained in May 2014 a variety of near-infrared observations of the very active Marum lava lake on Ambrym, Vanuatu, as well as the Strombolian activity at Yasur on Tanna. Our observations include high resolution images and movies made with standard and modified cameras and camcorders. In addition, to test the planetary emission models, which typically rely on multi-wavelength observations, we developed a small inexpensive prototype imager named "Kerby", which consists of three simultaneously active near-infrared cameras operating at 0.860, 0.775, and 0.675 microns, as well as a fourth visible wavelength RGB camera. This prototype is based on the Raspberry Pi and Pi-NoIR cameras. It can record full high definition video, and is light enough to be carried by backpack and run from batteries. To date we have concentrated on the analysis of the Marum data. During our observations of the 40 m diameter lava lake, convection was so vigorous that areas of thin crust formed only intermittently and persisted for tens of seconds to a few minutes at most. The convection pattern primarily consisted of two upwelling centers located about 8 m in from the margins on opposite sides of the lake. Horizontal velocities away from the upwelling centers were approximately 4 m/s. A hot bright margin roughly 0.4 m wide frequently formed around parts of the lake perimeter. We are in the process of establishing the absolute photometry calibration to obtain temperatures, temperature distributions, and magma cooling rates.

  2. MASSIVE YOUNG STELLAR OBJECTS IN THE GALACTIC CENTER. I. SPECTROSCOPIC IDENTIFICATION FROM SPITZER INFRARED SPECTROGRAPH OBSERVATIONS

    SciTech Connect

    An, Deokkeun; RamIrez, Solange V.; Boogert, A. C. Adwin; Sellgren, Kris; Arendt, Richard G.; Schultheis, Mathias; Cotera, Angela S.; Stolovy, Susan R.

    2011-08-01

    We present results from our spectroscopic study, using the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope, designed to identify massive young stellar objects (YSOs) in the Galactic center (GC). Our sample of 107 YSO candidates was selected based on Infrared Array Camera (IRAC) colors from the high spatial resolution, high sensitivity Spitzer/IRAC images in the Central Molecular Zone, which spans the central {approx}300 pc region of the Milky Way. We obtained IRS spectra over 5-35 {mu}m using both high- and low-resolution IRS modules. We spectroscopically identify massive YSOs by the presence of a 15.4 {mu}m shoulder on the absorption profile of 15 {mu}m CO{sub 2} ice, suggestive of CO{sub 2} ice mixed with CH{sub 3}OH ice on grains. This 15.4 {mu}m shoulder is clearly observed in 16 sources and possibly observed in an additional 19 sources. We show that nine massive YSOs also reveal molecular gas-phase absorption from CO{sub 2}, C{sub 2}H{sub 2}, and/or HCN, which traces warm and dense gas in YSOs. Our results provide the first spectroscopic census of the massive YSO population in the GC. We fit YSO models to the observed spectral energy distributions and find YSO masses of 8-23 M{sub sun}, which generally agree with the masses derived from observed radio continuum emission. We find that about 50% of photometrically identified YSOs are confirmed with our spectroscopic study. This implies a preliminary star formation rate of {approx}0.07 M{sub sun} yr{sup -1} at the GC.

  3. Modelling Herschel observations of infrared-dark clouds in the Hi-GAL survey

    NASA Astrophysics Data System (ADS)

    Stamatellos, D.; Griffin, M. J.; Kirk, J. M.; Molinari, S.; Sibthorpe, B.; Ward-Thompson, D.; Whitworth, A. P.; Wilcock, L. A.

    2010-11-01

    We demonstrate the use of the 3D Monte Carlo radiative transfer code PHAETHON to model infrared-dark clouds (IRDCs) that are externally illuminated by the interstellar radiation field (ISRF). These clouds are believed to be the earliest observed phase of high-mass star formation, and may be the high-mass equivalent of lower mass pre-stellar cores. We model three different cases as examples of the use of the code, in which we vary the mass, density, radius, morphology and internal velocity field of the IRDC. We show the predicted output of the models at different wavelengths chosen to match the observing wavebands of Herschel and Spitzer. For the wavebands of the long-wavelength Spectral and Photometric Imaging Receiver (SPIRE) photometer on Herschel, we also pass the model output through the SPIRE simulator to generate output images that are as close as possible to the ones that would be seen using SPIRE. We then analyse the images as if they were real observations, and compare the results of this analysis with the results of the radiative transfer models. We find that detailed radiative transfer modelling is necessary to accurately determine the physical parameters of IRDCs (e.g. dust temperature, density profile). This method is applied to study G29.55+00.18, an IRDC observed by the Herschel Infrared Galactic Plane Survey (Hi-GAL), and in the future it will be used to model a larger sample of IRDCs from the same survey. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. E-mail: d.stamatellos@astro.cf.ac.uk

  4. COMET 22P/KOPFF: DUST ENVIRONMENT AND GRAIN EJECTION ANISOTROPY FROM VISIBLE AND INFRARED OBSERVATIONS

    SciTech Connect

    Moreno, Fernando; Pozuelos, Francisco; Aceituno, Francisco; Casanova, Victor; Sota, Alfredo

    2012-06-20

    We present optical observations and Monte Carlo models of the dust coma, tail, and trail structures of the comet 22P/Kopff during the 2002 and 2009 apparitions. Dust loss rates, ejection velocities, and power-law size distribution functions are derived as functions of the heliocentric distance using pre- and post-perihelion imaging observations during both apparitions. The 2009 post-perihelion images can be accurately fitted by an isotropic ejection model. On the other hand, strong dust ejection anisotropies are required to fit the near-coma regions at large heliocentric distances (both inbound at r{sub h} = 2.5 AU and outbound at r{sub h} = 2.6 AU) for the 2002 apparition. These asymmetries are compatible with a scenario where dust ejection is mostly seasonally driven, coming mainly from regions near subsolar latitudes at far heliocentric distances inbound and outbound. At intermediate to near-perihelion heliocentric distances, the outgassing would affect much more extended latitude regions, the emission becoming almost isotropic near perihelion. We derived a maximum dust production rate of 260 kg s{sup -1} at perihelion, and an averaged production rate over one orbit of 40 kg s{sup -1}. An enhanced emission rate, also accompanied by a large ejection velocity, is predicted at r{sub h} > 2.5 pre-perihelion. The model has also been extended to the thermal infrared in order to be applied to available trail observations of this comet taken with IRAS and Infrared Space Observatory spacecrafts. The modeled trail intensities are in good agreement with those observations, which is remarkable taking into account that those data are sensitive to dust ejection patterns corresponding to several orbits before the 2002 and 2009 apparitions.

  5. Ground Based Observation of Isotopic Oxygen in the Martian Atmosphere Using Infrared Heterodyne Spectroscopy

    NASA Technical Reports Server (NTRS)

    Smith, R. L.; Kostiuk, T.; Livengood, T. A.; Fast, K. E.; Hewagama, T.; Delgado, J. D.; Sonnabend, G.

    2010-01-01

    Infrared heterodyne spectra of isotopic CO2 in the Martian atmosphere were obtained using the Goddard Heterodyne Instrument for Planetary Wind and Composition, HIPWAC, which was interfaced with the 3-meter telescope at the NASA Infrared Telescope Facility- Spectra were colle cted at a resolution of lambda/delta lambda=10(exp 7). Absorption fea tures of the CO2 isotopologues have been identified from which isotop ic ratios of oxygen have been determined. The isotopic ratios O-17/O -16 and O-18/O-16 in the Martian atmosphere can be related to Martian atmospheric evolution and can be compared to isotopic ratios of oxyg en in the Earth's atmosphere. Isotopic carbon and oxygen are importa nt constraints on any theory for the erosion of the Martian primordia l atmosphere and the interaction between the atmosphere and surface o r subsurface chemical reservoirs. This investigation explored the pr esent abundance of the stable isotopes of oxygen in Mars' atmospheric carbon dioxide by measuring rovibrational line absorption in isotop ic species of CO2 using groundbased infrared heterodyne spectroscopy in the vicinity of the 9.6 micron and 10.6 micron CO2 lasing bands. T he target transitions during this observation were O-18 C-12 O-16 as well as O-178 C-12 O-16 and O-16 C-113 O-16 at higher resolving power of lambda/delta lambda=10(exp 7) and with high signal-to-noise ratio (longer integration time) in order to fully characterize the absorpt ion line profiles. The fully-resolved lineshape of both the strong n ormal-isotope and the weak isotopic CO2 lines were measured simultane ously in a single spectrum.

  6. Observer-based robust finite time H∞ sliding mode control for Markovian switching systems with mode-dependent time-varying delay and incomplete transition rate.

    PubMed

    Gao, Lijun; Jiang, Xiaoxiao; Wang, Dandan

    2016-03-01

    This paper investigates the problem of robust finite time H∞ sliding mode control for a class of Markovian switching systems. The system is subjected to the mode-dependent time-varying delay, partly unknown transition rate and unmeasurable state. The main difficulty is that, a sliding mode surface cannot be designed based on the unknown transition rate and unmeasurable state directly. To overcome this obstacle, the set of modes is firstly divided into two subsets standing for known transition rate subset and unknown one, based on which a state observer is established. A component robust finite-time sliding mode controller is also designed to cope with the effect of partially unknown transition rate. It is illustrated that the reachability, finite-time stability, finite-time boundedness, finite-time H∞ state feedback stabilization of sliding mode dynamics can be ensured despite the unknown transition rate. Finally, the simulation results verify the effectiveness of robust finite time control problem.

  7. No evidence of a circumsolar dust ring from infrared observations of the 1991 solar eclipse.

    PubMed

    Lamy, P; Kuhn, J R; Lin, H; Koutchmy, S; Smartt, R N

    1992-09-04

    During the past 25 years there have been many attempts to detect a possible dust ring around the sun, with contradictory results. Before the 1991 eclipse, infrared eclipse experiments used single-element detectors to scan the corona along the ecliptic for excess surface brightness peaks. The availability of relatively large-format infrared array detectors now provides a considerable observational advantage: two-dimensional mapping of the brightness and polarization of the corona with high photometric precision. The 1991 eclipse path included the high-altitude Mauna Kea Observatory, a further advantage to measure the corona out to large angular distances from the sun. Results are reported from an experiment conducted on Mauna Kea with a HgCdTe-array detector sensitive to wavelengths between 1 and 2.5 micrometers, using broad-band J, H, and K filters. Although the sky conditions were not ideal, the H- and K-band surface brightnesses clearly show the inhomogeneous structure in the K-corona and the elliptical flattening of the F-corona, but no evidence of a circumsolar, local dust component out to 15 solar radii.

  8. Infrared observations of eight X-ray sources from Galactic plane surveys

    NASA Astrophysics Data System (ADS)

    Revnivtsev, M. G.; Kniazev, A.; Karasev, D. I.; Berdnikov, L.; Barway, S.

    2013-08-01

    Increasing the identification completeness of sources from new X-ray sky surveys is a necessary condition for further works on analyzing the formation and long-term evolution of star systems in our Galaxy. Infrared observations of several sources selected from Galactic plane surveys as candidates for low-mass X-ray binaries with the IRSF telescope at the South African Astronomical Observatory are presented. The infrared fluxes have been reliably measured from five of the eight sources (4U 1556-60, 4U 1708-40, AX J165901-4208, IGR J16287-5021, IGR J17350-2045, AX J171922-3703, SAX J1712.6-3739, 4U 1705-32). One of the objects (AX J165901-4208) may be a candidate for symbiotic X-ray binaries, i.e., binaries in which the companion of a relativistic object is a giant star. The distances have been estimated for three sources and the orbital periods have been estimated for two.

  9. Thermal Infrared Observations of Lava Flows During the 1984 Mauna Loa Eruption

    NASA Technical Reports Server (NTRS)

    Pieri, D. C.; Gillespie, R.; Kahle, A. B.; Kahle, J.; Baloga, S. M.

    1985-01-01

    Thermal infrared videotape images of the flowing lava streams and the vent areas at 10.6 microns were made, as well as some broadband images in the 8 to 12 micron range (for gas plume detection). These data were calibrated with on-site hand-held radiometer measurements, in-flow thermocouple measurements, and with later laboratory kiln measurements. Infrared video data are useful in quantitatively assessing the pattern and mode of flow thermal losses, particularly with regard to radiative losses from established/incipient floating crust. The general cooling of the flows downstream was readily apparent. Upper reaches of the active flow exhibited nearly crust-free main channels, radiating at about 700 to 800 degrees C. Below about the 7500 foot level (about 8 km from the vent) the flows formed nearly continuous crust and tended to spread, become less well-defined and founder due to a reduction in slope. Nevertheless, in thermal IR observations, the surface trace of the active subsurface channel was visible, radiating at about 500 to 700 degrees C. At the active flow front, most solid crust radiated at temperatures less than 500 to 600 degrees C, however bright high temperature interiors (approximately 900 to 1000 degrees C) were clearly visible though evolving fissures.

  10. WIDE-FIELD INFRARED SURVEY EXPLORER OBSERVATIONS OF THE EVOLUTION OF MASSIVE STAR-FORMING REGIONS

    SciTech Connect

    Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Padgett, D. L.; Rebull, L. M.

    2012-01-10

    We present the results of a mid-infrared survey of 11 outer Galaxy massive star-forming regions and 3 open clusters with data from the Wide-field Infrared Survey Explorer (WISE). Using a newly developed photometric scheme to identify young stellar objects and exclude extragalactic contamination, we have studied the distribution of young stars within each region. These data tend to support the hypothesis that latter generations may be triggered by the interaction of winds and radiation from the first burst of massive star formation with the molecular cloud material leftover from that earlier generation of stars. We dub this process the 'fireworks hypothesis' since star formation by this mechanism would proceed rapidly and resemble a burst of fireworks. We have also analyzed small cutout WISE images of the structures around the edges of these massive star-forming regions. We observe large (1-3 pc size) pillar and trunk-like structures of diffuse emission nebulosity tracing excited polycyclic aromatic hydrocarbon molecules and small dust grains at the perimeter of the massive star-forming regions. These structures contain small clusters of emerging Class I and Class II sources, but some are forming only a single to a few new stars.

  11. Wide-Field Infrared Survey Explorer Observations of the Evolution of Massive Star-Forming Regions

    NASA Technical Reports Server (NTRS)

    Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Rebull, L. M.; Padgett, D. L.; Asslef, R. J.

    2012-01-01

    We present the results of a mid-infrared survey of II outer Galaxy massive star-forming regions and 3 open clusters with data from the Wide-field Infrared Survey Explorer (WISE). Using a newly developed photometric scheme to identify young stellar objects and exclude extragalactic contamination, we have studied the distribution of young stars within each region. These data tend to support the hypothesis that latter generations may be triggered by the interaction of winds and radiation from the first burst of massive star formation with the molecular cloud material leftover from that earlier generation of stars. We dub this process the "fireworks hypothesis" since star formation by this mechanism would proceed rapidly and resemble a burst of fireworks. We have also analyzed small cutout WISE images of the structures around the edges of these massive star-forming regions. We observe large (1-3 pc size) pillar and trunk-like structures of diffuse emission nebulosity tracing excited polycyclic aromatic hydrocarbon molecules and small dust grains at the perimeter of the massive star-forming regions. These structures contain small clusters of emerging Class I and Class II sources, but some are forming only a single to a few new stars.

  12. Wide-Field Infrared Survey Explorer Observations of the Evolution of Massive Star-Forming Regions

    NASA Technical Reports Server (NTRS)

    Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Rebull, L. M.; Padgett, D. L.; Assef, R. J.

    2011-01-01

    We present the results of a mid-infrared survey of 11 outer Galaxy massive star-forming regions and 3 open clusters with data from the Wide-field Infrared Survey Explorer (WISE). Using a newly developed photometric scheme to identify young stellar objects and exclude extragalactic contamination, we have studied the distribution of young stars within each region. These data tend to support the hypothesis that latter generations may be triggered by the interaction of winds and radiation from the first burst of massive star formation with the molecular cloud material leftover from that earlier generation of stars.We dub this process the "fireworks hypothesis" since star formation by this mechanism would proceed rapidly and resemble a burst of fireworks.We have also analyzed small cutout WISE images of the structures around the edges of these massive star-forming regions. We observe large (1-3 pc size) pillar and trunk-like structures of diffuse emission nebulosity tracing excited polycyclic aromatic hydrocarbon molecules and small dust grains at the perimeter of the massive star-forming regions. These structures contain small clusters of emerging Class I and Class II sources, but some are forming only a single to a few new stars.

  13. Observation of several chlorine nitrate (ClONO2) bands in stratospheric infrared spectra

    NASA Technical Reports Server (NTRS)

    Zander, R.; Rinsland, C. P.; Farmer, C. B.; Brown, L. R.; Norton, R. H.

    1986-01-01

    Four of the most prominent and sharpest infrared absorption features of chlorine nitrate at 780.2, 807.7, 809.4, and 1292.6/cm have been observed in a series of infrared solar spectra obtained at an unapodized spectral resolution of 0.01/cm, using the Atmospheric Trace Molecule Spectroscopy instrument from on-board Sapcelab 3. A quantitative analysis of the nu4 Q branch at 780.2/cm has provided insight into the concentration of ClONO2 between 19 and 40 km altitude. While the mean profile deduced from three sunset occultations near 30 deg N latitude exhibits a shape close to that predicted by model calculations, its concentrations in the 20 to 32 km altitude range are, however, about 30 percent larger, reaching a peak concentration of 9 x 10 to the 8th molecules/cu cm at 25 km. The concentrations above 32 km, deduced from one sunrise occultation at 47 deg JS, are even larger than the corresponding sunset values at 30 deg N latitude. Some of these discrepancies may be caused by the rather large uncertainty in the assumed Q branch strength.

  14. Wide-Field Infrared Survey Explorer Observations of the Evolution of Massive Star-Forming Regions

    NASA Technical Reports Server (NTRS)

    Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Rebull, L. M.; Padgett, D. L.; Asslef, R. J.

    2012-01-01

    We present the results of a mid-infrared survey of II outer Galaxy massive star-forming regions and 3 open clusters with data from the Wide-field Infrared Survey Explorer (WISE). Using a newly developed photometric scheme to identify young stellar objects and exclude extragalactic contamination, we have studied the distribution of young stars within each region. These data tend to support the hypothesis that latter generations may be triggered by the interaction of winds and radiation from the first burst of massive star formation with the molecular cloud material leftover from that earlier generation of stars. We dub this process the "fireworks hypothesis" since star formation by this mechanism would proceed rapidly and resemble a burst of fireworks. We have also analyzed small cutout WISE images of the structures around the edges of these massive star-forming regions. We observe large (1-3 pc size) pillar and trunk-like structures of diffuse emission nebulosity tracing excited polycyclic aromatic hydrocarbon molecules and small dust grains at the perimeter of the massive star-forming regions. These structures contain small clusters of emerging Class I and Class II sources, but some are forming only a single to a few new stars.

  15. Wide-Field Infrared Survey Explorer Observations of the Evolution of Massive Star-Forming Regions

    NASA Technical Reports Server (NTRS)

    Koenig, X. P.; Leisawitz, D. T.; Benford, D. J.; Rebull, L. M.; Padgett, D. L.; Assef, R. J.

    2011-01-01

    We present the results of a mid-infrared survey of 11 outer Galaxy massive star-forming regions and 3 open clusters with data from the Wide-field Infrared Survey Explorer (WISE). Using a newly developed photometric scheme to identify young stellar objects and exclude extragalactic contamination, we have studied the distribution of young stars within each region. These data tend to support the hypothesis that latter generations may be triggered by the interaction of winds and radiation from the first burst of massive star formation with the molecular cloud material leftover from that earlier generation of stars.We dub this process the "fireworks hypothesis" since star formation by this mechanism would proceed rapidly and resemble a burst of fireworks.We have also analyzed small cutout WISE images of the structures around the edges of these massive star-forming regions. We observe large (1-3 pc size) pillar and trunk-like structures of diffuse emission nebulosity tracing excited polycyclic aromatic hydrocarbon molecules and small dust grains at the perimeter of the massive star-forming regions. These structures contain small clusters of emerging Class I and Class II sources, but some are forming only a single to a few new stars.

  16. Thermal Infrared Observations of Lava Flows During the 1984 Mauna Loa Eruption

    NASA Technical Reports Server (NTRS)

    Pieri, D. C.; Gillespie, R.; Kahle, A. B.; Kahle, J.; Baloga, S. M.

    1985-01-01

    Thermal infrared videotape images of the flowing lava streams and the vent areas at 10.6 microns were made, as well as some broadband images in the 8 to 12 micron range (for gas plume detection). These data were calibrated with on-site hand-held radiometer measurements, in-flow thermocouple measurements, and with later laboratory kiln measurements. Infrared video data are useful in quantitatively assessing the pattern and mode of flow thermal losses, particularly with regard to radiative losses from established/incipient floating crust. The general cooling of the flows downstream was readily apparent. Upper reaches of the active flow exhibited nearly crust-free main channels, radiating at about 700 to 800 degrees C. Below about the 7500 foot level (about 8 km from the vent) the flows formed nearly continuous crust and tended to spread, become less well-defined and founder due to a reduction in slope. Nevertheless, in thermal IR observations, the surface trace of the active subsurface channel was visible, radiating at about 500 to 700 degrees C. At the active flow front, most solid crust radiated at temperatures less than 500 to 600 degrees C, however bright high temperature interiors (approximately 900 to 1000 degrees C) were clearly visible though evolving fissures.

  17. Infrared Observations of the Orion Capsule During EFT-1 Hypersonic Reentry

    NASA Technical Reports Server (NTRS)

    Horvath, Thomas J.; Rufer, Shann J.; Schuster, David M.; Mendeck, Gavin F.; Oliver, A. Brandon; Schwartz, Richard J.; Verstynen, Harry A.; Mercer, C. David; Tack, Steven; Ingram, Ben; hide

    2016-01-01

    High-resolution infrared observations of the Orion capsule during its atmospheric reentry on December 5, 2015 were made from a US Navy NP-3D. This aircraft, equipped with a long-range optical sensor system, tracked the capsule from Mach 10 to 7 from a distance of approximately 60 nmi. Global surface temperatures of the capsule's thermal heatshield were derived from near infrared intensity measurements. The global surface temperature measurements complemented onboard instrumentation and were invaluable to the interpretation of the in-depth thermocouple measurements which rely on inverse heat transfer methods and material response codes to infer the desired surface temperature from the sub-surface measurements. The full paper will address the motivations behind the NASA Engineering Safety Center sponsored observation and highlight premission planning processes with an emphasis on aircraft placement, optimal instrument configuration and sensor calibrations. Critical aspects of mission operations coordinated from the NASA Johnson Spaceflight Center and integration with the JSC Flight Test Management Office will be discussed. A summary of the imagery that was obtained and processed to global surface temperature will be presented. At the capsule's point of closest approach relative to the imaging system, the spatial resolution was estimated to be approximately 15-inches per pixel and was sufficient to identify localized temperature increases associated with compression pad support hardware on the heatshield. The full paper will discuss the synergy of the quantitative imagery derived temperature maps with in-situ thermocouple measurements. Comparison of limited onboard surface thermocouple data to the image derived surface temperature will be presented. The two complimentary measurements serve as an example of the effective leveraging of resources to advance the understanding of high Mach number environments associated with an ablated heatshield and provide unique data

  18. Mid-infrared observations of O-type stars: spectral morphology

    NASA Astrophysics Data System (ADS)

    Marcolino, W. L. F.; Bouret, J.-C.; Lanz, T.; Maia, D. S.; Audard, M.

    2017-09-01

    We present mid-infrared (mid-IR) observations for a sample of 16 O-type stars. The data were acquired with the NASA Spitzer Space Telescope, using the IRS instrument at moderate resolution (R ∼ 600), covering the range of ∼10-37 μm. Our sample includes early, mid and late O supergiants and dwarfs. We explore for the first time their mid-IR spectral morphology in a quantitative way. We use NLTE expanding atmosphere models to help with line identifications, analyse profile contributions and line-formation regions. The O supergiants present a rich emission line spectra. The most intense features are from hydrogen - 6 α, 7 α and 8 α - that have non-negligible contributions of He i or He ii lines, depending on the spectral type. The spectrum of early O supergiants is a composite of H i and He ii lines, He i lines being absent. On the other hand, late O supergiants present features composed mainly by H i and He i lines. All emission lines are formed throughout the stellar wind. We found that O dwarfs exhibit a featureless mid-IR spectrum. Two stars of our sample exhibit very similar mid-IR features, despite having a very different optical spectral classification. The analysis of O-type stars based on mid-IR spectra alone to infer spectral classes or to estimate physical parameters may thus be prone to substantial errors. Our results may therefore inform spectroscopic observations of massive stars located in heavily obscured regions and help establish an initial framework for observations of massive stars using the Mid-Infrared Instrument on the James Webb Space Telescope.

  19. Contribution of ultraviolet and shortwave infrared observations to atmospheric correction of PACE ocean-color imagery

    NASA Astrophysics Data System (ADS)

    Frouin, Robert J.; Gross-Colzy, Lydwine S.

    2016-05-01

    The Pre-Aerosol, Cloud, and ocean Ecosystem (PACE) mission will carry into space a spectrometer measuring at 5 nm resolution in the ultraviolet (UV) to near infrared (NIR) and at lower resolution in spectral bands in the NIR and shortwave infrared (SWIR). These observations have great potential for improving estimates of marine reflectance in the post-EOS era. In view of this, we evaluate, using simulations with a coupled radiation transfer code, the gain in marine reflectance accuracy expected by including observations in the UV and SWIR compared with just using observations in the visible to NIR. The study is performed for the PACE threshold aggregate bands with respect to the standard set of bands used to generate ocean color products. The top-of-atmosphere (TOA) signal measured by the PACE spectrometer is simulated for a variety of realistic atmospheric and oceanic conditions. The TOA reflectance and the marine reflectance of the simulated ensemble are decomposed into principal components, and the components of the TOA reflectance sensitive to the ocean signal identified. Inverse models are constructed to retrieve the principal components of the marine reflectance, allowing a reconstruction, therefore an estimation of the marine reflectance. Theoretical performance is quantified as a function of angular geometry, aerosol properties, and water type, showing a significant improvement in retrieval accuracy when using the extended spectral range. On average over all the situations considered (including sun glint), the RMS error is reduced from 0.0037 to 0.0024 at 412 nm, from 0.0013 to 0.0007 at 665 nm, and from 0.0010 to 0.0004 at 865 nm (Case 2 waters are better handled). The performance is degraded at large zenith angles and aerosol optical thickness, is better at scattering angles around 120-130 degrees, and exhibits little dependence on aerosol single scattering albedo and aerosol scale height.

  20. Modelling Middle Infrared Thermal Imagery from Observed or Simulated Active Fire

    NASA Astrophysics Data System (ADS)

    Paugam, R.; Gastellu-Etchegorry, J. P.; Mell, W.; Johnston, J.; Filippi, J. B.

    2016-12-01

    The Fire Radiative Power (FRP) is used in the atmospheric and fire communities to estimate fire emission. For example, the current version of the emission inventory GFAS is using FRP observation from the MODIS sensors to derive daily global distribution of fire emissions. Although the FRP product is widely accepted, most of its theoretical justifications are still based on small scale burns. When up-scaling to large fires effects of view angle, canopy cover, or smoke absorption are still unknown. To cover those questions, we are building a system based on the DART radiative transfer model to simulate the middle infrared radiance emitted by a propagating fire front and propagating in the surrounding scene made of ambient vegetation and plume aerosols. The current version of the system was applied to fire ranging from a 1m2 to 7ha. The 3D fire scene used as input in DART is made of the flame, the vegetation (burnt and unburnt), and the plume. It can be either set up from [i] 3D physical based model scene (ie WFDS, mainly applicable for small scale burn), [ii] coupled 2D fire spread - atmospheric models outputs (eg ForeFire-MesoNH) or [iii] derived from thermal imageries observations (here plume effects are not considered). In the last two cases, as the complexity of physical processes occurring in the flame (in particular soot formation and emission) is not to solved, the flames structures are parameterized with (a) temperature and soot concentration based on empirical derived profiles and (b) 3D triangular shape hull interpolated at the fire front location. Once the 3D fire scene is set up, DART is then used to render thermal imageries in the middle infrared. Using data collected from burns conducted at different scale, the modelled thermal imageries are compared against observations, and effects of view angle are discussed.

  1. A global climatology of stratospheric gravity waves from Atmospheric Infrared Sounder observations

    NASA Astrophysics Data System (ADS)

    Hoffmann, Lars; Xue, Xianghui; Alexander, M. Joan

    2014-05-01

    We present the results of a new study that aims on the detection and classification of `hotspots' of stratospheric gravity waves on a global scale. The analysis is based on a nine-year record (2003 to 2011) of radiance measurements by the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite. We detect the presence of stratospheric gravity waves based on 4.3 micron brightness temperature variances. Our method is optimized for peak events, i.e., strong gravity wave events for which the local variance considerably exceeds background levels. We estimated the occurrence frequencies of these peak events for different seasons and time of day and used the results to find local maxima of gravity wave activity. In addition, we use AIRS radiances at 8.1 micron to simultaneously detect convective events, including deep convection in the tropics and mesoscale convective systems at mid latitudes. We classified the gravity waves according to their sources, based on seasonal occurrence frequencies for convection and by means of topographic data. Our study reproduces well-known hotspots of gravity waves, e.g., the mountain wave hotspots at the Andes and the Antarctic Peninsula or the convective hotspot during the thunderstorm season over the North American Great Plains. However, the high horizontal resolution of the AIRS observations also helped us to locate several smaller hotspots, which were partly unknown or poorly studied so far. Most of these smaller hotspots are found near orographic features like small mountain ranges, in coastal regions, in desert areas, or near isolated islands. This new study will help to select the most promising regions and seasons for future observational studies of gravity waves. Reference: Hoffmann, L., X. Xue, and M. J. Alexander, A global view of stratospheric gravity wave hotspots located with Atmospheric Infrared Sounder observations, J. Geophys. Res., 118, 416-434, doi:10.1029/2012JD018658, 2013.

  2. Thermal infrared observations of Mars (7.5-12.8 microns) during the 1990 opposition

    NASA Technical Reports Server (NTRS)

    Roush, T. L.; Witteborn, F.; Lucy, P. G.; Graps, A.; Pollack, J. B.

    1991-01-01

    Thirteen spectra of Mars, in the 7.5 to 12.8 micron wavelength were obtained on 7 Dec. 1990 from the Infrared Telescope Facility (IRTF). For these observations, a grating with an ultimate resolving power of 120 to 250 was used and wavelengths were calibrated for each grating setting by comparison with the absorption spectrum of polystyrene measured prior to each set of observations. By sampling the Nyquist limit at the shortest wavelengths, an effective resolving power of about 120 over the entire wavelength range was achieved. A total of four grating settings were required to cover the entire wavelength region. A typical observing sequence consisted of: (1) positioning the grating in one of the intervals; (2) calibrating the wavelength of positions; and (3) obtaining spectra for a number of spots on Mars. Several observations of the nearby stellar standard star, alpha Tauri, were also acquired throughout the night. Each Mars spectrum represents an average of 4 to 6 measurements of the individual Mars spots. As a result of this observing sequence, the viewing geometry for a given location or spot on Mars does not change, but the actual location of the spot on Mars's surface varies somewhat between the different grating settings. Other aspects of the study are presented.

  3. Finite difference method for solving the Schroedinger equation with band nonparabolicity in mid-infrared quantum cascade lasers

    SciTech Connect

    Cooper, J. D.; Valavanis, A.; Ikonic, Z.; Harrison, P.; Cunningham, J. E.

    2010-12-01

    The nonparabolic Schroedinger equation for electrons in quantum cascade lasers (QCLs) is a cubic eigenvalue problem (EVP) which cannot be solved directly. While a method for linearizing this cubic EVP has been proposed in principle for quantum dots [Hwang et al., Math. Comput. Modell., 40, 519 (2004)] it was deemed too computationally expensive because of the three-dimensional geometry under consideration. We adapt this linearization approach to the one-dimensional geometry of QCLs, and arrive at a direct and exact solution to the cubic EVP. The method is then compared with the well established shooting method, and it is shown to be more accurate and reliable for calculating the bandstructure of mid-infrared QCLs.

  4. High-dispersion infrared spectroscopic observations of comet 8P/Tuttle with VLT/CRIRES

    NASA Astrophysics Data System (ADS)

    Kobayashi, H.; Bockelée-Morvan, D.; Kawakita, H.; Dello Russo, N.; Jehin, E.; Manfroid, J.; Smette, A.; Hutsemékers, D.; Stüwe, J.; Weiler, M.; Arpigny, C.; Biver, N.; Cochran, A.; Crovisier, J.; Magain, P.; Sana, H.; Schulz, R.; Vervack, R. J.; Weaver, H.; Zucconi, J.-M.

    2010-01-01

    We report on the composition of the Halley-family comet (HFC) 8P/Tuttle investigated with high-dispersion near-infrared spectroscopic observations. The observations were carried out at the ESO VLT (Very Large Telescope) with the CRIRES instrument as part of a multi-wavelength observation campaign of 8P/Tuttle performed in late January and early February 2008. Radar observations suggested that 8P/Tuttle is a contact binary, and it was proposed that these components might be heterogeneous in chemistry. We determined mixing ratios of organic volatiles with respect to H2O and found that mixing ratios were consistent with previous near infrared spectroscopic observations obtained in late December 2007 and in late January 2008. It has been suggested that because 8P/Tuttle is a contact binary, it might be chemically heterogeneous. However, we find no evidence for chemical heterogeneity within the nucleus of 8P/Tuttle. We also compared the mixing ratios of organic molecules in 8P/Tuttle with those of both other HFCs and long period comets (LPCs) and found that HCN, C2H2, and C2H6 are depleted whereas CH4 and CH3OH have normal abundances. This may indicate that 8P/Tuttle was formed in a different region of the early solar nebula than other HFCs and LPCs. We estimated the conversion efficiency from C2H2 to C2H6 by hydrogen addition reactions on cold grains by employing the C2H6/(C2H6+C2H2) ratio. The C2H6/(C2H6+C2H2) ratio in 8P/Tuttle is consistent with the ratios found in other HFCs and LPCs within the error bars. We also discuss the source of C2 and CN based on our observations and conclude that the abundances of C2H2 and C2H6 are insufficient to explain the C2 abundances in comet 8P/Tuttle and that the abundance of HCN is insufficient to explain the CN abundances in the comet, so at least one additional parent is needed for each species, as pointed out in previous study. Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO Prog. 080.C

  5. CASSIS: The Cornell Atlas of Spitzer/Infrared Spectrograph Sources. II. High-resolution Observations

    NASA Astrophysics Data System (ADS)

    Lebouteiller, V.; Barry, D. J.; Goes, C.; Sloan, G. C.; Spoon, H. W. W.; Weedman, D. W.; Bernard-Salas, J.; Houck, J. R.

    2015-06-01

    The Infrared Spectrograph (IRS) on board the Spitzer Space Telescope observed about 15,000 objects during the cryogenic mission lifetime. Observations provided low-resolution (R=λ /{Δ }λ ≈ 60-127) spectra over ≈ 5-38 μm and high-resolution (R≈ 600) spectra over 10-37 μm. The Cornell Atlas of Spitzer/IRS Sources (CASSIS) was created to provide publishable quality spectra to the community. Low-resolution spectra have been available in CASSIS since 2011, and here we present the addition of the high-resolution spectra. The high-resolution observations represent approximately one-third of all staring observations performed with the IRS instrument. While low-resolution observations are adapted to faint objects and/or broad spectral features (e.g., dust continuum, molecular bands), high-resolution observations allow more accurate measurements of narrow features (e.g., ionic emission lines) as well as a better sampling of the spectral profile of various features. Given the narrow aperture of the two high-resolution modules, cosmic ray hits and spurious features usually plague the spectra. Our pipeline is designed to minimize these effects through various improvements. A super-sampled point-spread function was created in order to enable the optimal extraction in addition to the full aperture extraction. The pipeline selects the best extraction method based on the spatial extent of the object. For unresolved sources, the optimal extraction provides a significant improvement in signal-to-noise ratio over a full aperture extraction. We have developed several techniques for optimal extraction, including a differential method that eliminates low-level rogue pixels (even when no dedicated background observation was performed). The updated CASSIS repository now includes all the spectra ever taken by the IRS, with the exception of mapping observations.

  6. Observing Mesoscale Gravity Waves by Tomographic inversion of Infrared Limb-sounder Measurements

    NASA Astrophysics Data System (ADS)

    Ungermann, Joern; Hoffmann, Lars; Preusse, Peter; Kaufmann, Martin; Riese, Martin

    PREMIER is one of three candidates for ESA's 7th Earth Explorer mission that are currently undergoing feasibility studies. The main mission objective is to quantify processes controlling atmospheric composition in the mid/upper troposphere and lower stratosphere, a region of particular importance for climate change. PREMIER will therefore employ the first satellite Fourier transform infrared limb-imager combined with a millimetre-wave limb-sounder. The infrared limb-imager can be operated in a high spatial resolution mode for observations of small-scale structures in atmospheric temperatures and trace gas fields with unprecedented 3D sampling (0.5 km in the vertical direction, 50 km along track, 25 km across track). Global observations of gravity waves (GW) is a major objective of the PREMIER mission. GWs represent an important coupling mechanism for the middle atmosphere. They contribute to the driving of the quasi-biennial oscillation by about 50 %, are the major forcing mechanism of the summer branch of the Brewer-Dobson circulation, and contribute 30 to 50 % to the predicted increase of the Brewer-Dobson circulation due to climate change. GWs are also the main driver of mesospheric winds and cause the cold summer mesopause. We present a fast tomographic retrieval scheme, which is designed to fully exploit the high-resolution radiance observations of the dynamics mode. Based on a detailed analysis of the 'observational filter', we show that the dynamics mode provides unique information on global distributions of gravity waves. For comparison we also applied a conventional one-dimensional retrieval scheme, assuming a homogeneously stratified atmosphere. Based on an analysis of small-and meso-scale temperature wave perturbations (which may arise in the stratosphere due GWs) we find that the two-dimensional approach is much better capable of retrieving these structures. The achievable vertical resolution has values between the vertical sampling (0.5 km) of the

  7. Far-infrared observations of thermal dust emission from supernova 1987A

    NASA Technical Reports Server (NTRS)

    Moseley, S. H.; Dwek, E.; Glaccum, W.; Graham, J. R.; Loewenstein, R. F.

    1989-01-01

    Observations of SN1987A in the spectral range 18-35 microns taken on November 16 and 23, 1988, 632 and 639 days after core collapse, are reported. A strong and rather flat continuum underlies weak fine-structure lines from heavy elements and declines slowly between 24 and 30 microns. The spectral shape indicates thermal emission from an almost featureless dust component, probably graphite, with silicates contributing less than 20 percent of the emitting dust mass. Some of the emission may be an 'echo' of supernova light reflected from a preexisting dust cloud, but a better explanation which can account for the entirety of emission from infrared to gamma wavelengths, is that dust is being formed in the supernova ejecta. This also accounts more naturally for the inferred dust composition.

  8. Observation of correlated electronic decay in expanding clusters triggered by near-infrared fields

    PubMed Central

    Schütte, B.; Arbeiter, M.; Fennel, T.; Jabbari, G.; Kuleff, A.I.; Vrakking, M.J.J.; Rouzée, A.

    2015-01-01

    When an excited atom is embedded into an environment, novel relaxation pathways can emerge that are absent for isolated atoms. A well-known example is interatomic Coulombic decay, where an excited atom relaxes by transferring its excess energy to another atom in the environment, leading to its ionization. Such processes have been observed in clusters ionized by extreme-ultraviolet and X-ray lasers. Here, we report on a correlated electronic decay process that occurs following nanoplasma formation and Rydberg atom generation in the ionization of clusters by intense, non-resonant infrared laser fields. Relaxation of the Rydberg states and transfer of the available electronic energy to adjacent electrons in Rydberg states or quasifree electrons in the expanding nanoplasma leaves a distinct signature in the electron kinetic energy spectrum. These so far unobserved electron-correlation-driven energy transfer processes may play a significant role in the response of any nano-scale system to intense laser light. PMID:26469997

  9. Diatomic molecules in the solar infrared spectrum from ATMOS-SL 3 high resolution observations

    NASA Technical Reports Server (NTRS)

    Grevesse, Nicolas; Sauval, A. J.; Farmer, C. B.; Norton, R. H.

    1987-01-01

    The ATMOS Fourier Transform Spectrometer has observed, for the first time, the solar infrared spectrum, from 2 to 16 microns, free of any telluric absorption. A very large number of molecular lines are present on these high quality spectra: vibration-rotation lines of CO (Delta-v = 1 and 2; including the isotopic species C-13, O-18 and O-17), CH, NH, OH and pure rotation lines of OH. The analysis of these lines will allow to derive accurate values for the solar abundances of C, N and O and the isotopic ratios C-13/C-12, O-18/O-16, and O-17/O-16, to test the photospheric model from high to deep layers, to test the electric dipole moment functions of the different molecules and to derive much better molecular constants for CH.

  10. Infrared speckle observations of io: an eruption in the loki region.

    PubMed

    Howell, R R; McGinn, M T

    1985-10-04

    Speckle observations of Jupiter's satellite Io at a wavelength of 5 micrometers during July 1984 resolved the disk and showed emission from a hot spot in the Loki region. The hot spot contributed a flux approximately equal to 60 percent of that from the disk. Images reconstructed by means of the Knox-Thompson algorithm showed the spot moving across the disk as the satellite rotated. It was located at 301 degrees +/- 6 degrees west longitude, 10 degrees +/- 6 degrees north latitude, and had a radiance of (2.96 +/- 0.54) x 10(22) ergs sec(-1) cm(-1) sr(-1)/A where A is the area of the spot. For an assumed temperature of 400 K, the area of the source would be 11,400 square kilometers. An active "lava lake" similar to that seen by Voyager may be the source of the infrared emission.

  11. Infrared speckle observations of Io - An eruption in the Loki region

    NASA Technical Reports Server (NTRS)

    Howell, R. R.; Mcginn, M. T.

    1985-01-01

    Speckle observations of Jupiter's satellite Io at a wavelength of 5 micrometers during July 1984 resolved the disk and showed emission from a hot spot in the Loki region. The hot spot contributed a flux approximately equal to 60 percent of that from the disk. Images reconstructed by means of the Knox-Thompson algorithm showed the spot moving across the disk as the satellite rotated. It was located at 301 deg + or - 6 deg west longitude, 10 deg + or - 6 deg north latitude, and had a radiance of (2.96 + or - 0.54) x 10 to the 22nd ergs/sec cm sr/A where A is the area of the spot. For an assumed temperature of 400 K, the area of the source would be 11,400 square kilometers. An active 'lava lake' similar to that seen by Voyager may be the source of the infrared emission.

  12. Observation of correlated electronic decay in expanding clusters triggered by near-infrared fields

    NASA Astrophysics Data System (ADS)

    Schütte, B.; Arbeiter, M.; Fennel, T.; Jabbari, G.; Kuleff, A. I.; Vrakking, M. J. J.; Rouzée, A.

    2015-10-01

    When an excited atom is embedded into an environment, novel relaxation pathways can emerge that are absent for isolated atoms. A well-known example is interatomic Coulombic decay, where an excited atom relaxes by transferring its excess energy to another atom in the environment, leading to its ionization. Such processes have been observed in clusters ionized by extreme-ultraviolet and X-ray lasers. Here, we report on a correlated electronic decay process that occurs following nanoplasma formation and Rydberg atom generation in the ionization of clusters by intense, non-resonant infrared laser fields. Relaxation of the Rydberg states and transfer of the available electronic energy to adjacent electrons in Rydberg states or quasifree electrons in the expanding nanoplasma leaves a distinct signature in the electron kinetic energy spectrum. These so far unobserved electron-correlation-driven energy transfer processes may play a significant role in the response of any nano-scale system to intense laser light.

  13. Corrosion of nickel metal by hydrothermal sodium tungstate solution observed by in-situ infrared spectroscopy

    SciTech Connect

    Hoffmann, M.M.; Fulton, J.L.

    2000-05-01

    Corrosion of nickel metal in a high-temperature aqueous tungstate solution was described. The corrosion altered the solution's pH, which affected the equilibrium of the solution chemistry. These secondary effects of the corrosion process were observed with in-situ infrared (IR) spectroscopy, demonstrating that important information on corrosion phenomena at the solid-fluid interface may be obtained from in-situ spectroscopic studies of the fluid phase. Subsequent scanning electron microscopy (SEM) analysis of the corroded nickel metal and solid corrosion products support conclusions drawn from solution chemistry measurements. The presented findings are of interest to researchers and engineers that use pure nickel or nickel-bearing alloys as a material for high-temperature, high-pressure applications in aqueous solutions.

  14. Application of an automatic cloud tracking technique to Meteosat water vapor and infrared observations

    NASA Technical Reports Server (NTRS)

    Endlich, R. M.; Wolf, D. E.

    1980-01-01

    The automatic cloud tracking system was applied to METEOSAT 6.7 micrometers water vapor measurements to learn whether the system can track the motions of water vapor patterns. Data for the midlatitudes, subtropics, and tropics were selected from a sequence of METEOSAT pictures for 25 April 1978. Trackable features in the water vapor patterns were identified using a clustering technique and the features were tracked by two different methods. In flat (low contrast) water vapor fields, the automatic motion computations were not reliable, but in areas where the water vapor fields contained small scale structure (such as in the vicinity of active weather phenomena) the computations were successful. Cloud motions were computed using METEOSAT infrared observations (including tropical convective systems and midlatitude jet stream cirrus).

  15. Infrared observation of a new mixed trimer, CO - (CO2)2

    NASA Astrophysics Data System (ADS)

    Barclay, A. J.; McKellar, A. R. W.; Moazzen-Ahmadi, N.

    2017-06-01

    The infrared spectrum of the weakly-bound trimer CO - (CO2)2 is observed in the carbon monoxide CO stretch region. Both 12C16O - (12C16O2)2 and 12C16O - (12C18O2)2 isotopologues are studied. The trimer band which is composed uniquely of b-type transitions and with missing levels establishes the trimer structure as that of a CO2 dimer plus a CO monomer aligned along the dimer C2 symmetry axis. The dimer to monomer center of mass separation is 3.55 Å, and the structural parameters within the CO2 dimer subunit are about 3.45 Å and 58°. It is not certain if the (CO2)2 remains planar within the trimer.

  16. Infrared speckle observations of Io - an eruption in the Loki region

    SciTech Connect

    Howell, R.R.; Mcginn, M.T.

    1985-10-01

    Speckle observations of Jupiter's satellite Io at a wavelength of 5 micrometers during July 1984 resolved the disk and showed emission from a hot spot in the Loki region. The hot spot contributed a flux approximately equal to 60 percent of that from the disk.Images reconstructed by means of the Knox-Thompson algorithm showed the spot moving across the disk as the satellite rotated. It was located at 301 deg + or - 6 deg west longitude, 10 deg + or - 6 deg north latitude, and had a radiance of (2.96 + or - 0.54) x 10 to the 22nd ergs/sec cm sr/A where A is the area of the spot. For an assumed temperature of 400 K, the area of the source would be 11,400 square kilometers. An active lava lake similar to that seen by Voyager may be the source of the infrared emission. 10 references.

  17. Infrared speckle observations of Io - An eruption in the Loki region

    NASA Technical Reports Server (NTRS)

    Howell, R. R.; Mcginn, M. T.

    1985-01-01

    Speckle observations of Jupiter's satellite Io at a wavelength of 5 micrometers during July 1984 resolved the disk and showed emission from a hot spot in the Loki region. The hot spot contributed a flux approximately equal to 60 percent of that from the disk. Images reconstructed by means of the Knox-Thompson algorithm showed the spot moving across the disk as the satellite rotated. It was located at 301 deg + or - 6 deg west longitude, 10 deg + or - 6 deg north latitude, and had a radiance of (2.96 + or - 0.54) x 10 to the 22nd ergs/sec cm sr/A where A is the area of the spot. For an assumed temperature of 400 K, the area of the source would be 11,400 square kilometers. An active 'lava lake' similar to that seen by Voyager may be the source of the infrared emission.

  18. High Resolution Radio Observations Of Energetically Dominant Regions In Local Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Barcos-Munoz, Loreto

    2016-07-01

    Luminous and Ultra-luminous Infrared galaxies (U/LIRGs) are one of the most powerful classes of extragalactic objects in the local universe, and they provide a unique opportunity to study star formation and feedback processes in extreme environments. They are primarily observed to be interacting or merging disk galaxies. During the interaction, large amounts of gas are funneled to the central few kpc, triggering high star formation rates (SFR) and dust production. The absorption of UV and optical radiation from stars, or active galactic nuclei (AGN), by dust produces their observed high infrared luminosities.The high level of dust obscuration intrinsic to U/LIRGs makes them difficult to study. Radio interferometry is thus the perfect tool for revealing the nature of these systems - it provides the high spatial resolution needed to resolve energetically dominant regions in U/LIRGs at wavelengths that have both diagnostic power and transparency to dust. In this thesis, 6 and 33 GHz radio continuum interferometric observations with the upgraded Karl G. Jansky Very Large Array (VLA) are used to study a sample of 22 local U/LIRGs.First, a detailed analysis of the 6 and 33 GHz radio continuum emission from the closest ULIRG, Arp 220, is presented. This late stage merger is highly obscured, being optically thick even at mid-infrared wavelengths. Further, due to its extreme environment, it is often used as a template for high redshift starbursts. Arp 220 hosts two distinct nuclei that are separated by (\\sim) 370 pc. The nuclei are well resolved with the 33 GHz observations (i.e., with a spatial resolution of ˜ 30 pc). The deconvolved radii enclosing half of the total 33 GHz light are approximately 50 and 35 pc for the eastern and western nucleus, respectively. Literature values of the gas mass and infrared luminosity are combined with the 33 GHz sizes under the assumption of co-spatiality to show that Arp 220 has one of the highest molecular gas surface densities

  19. VizieR Online Data Catalog: Near-infrared observations of 84 KOI systems (Atkinson+, 2017)

    NASA Astrophysics Data System (ADS)

    Atkinson, D.; Baranec, C.; Ziegler, C.; Law, N.; Riddle, R.; Morton, T.

    2017-06-01

    The initial observations identifying companion candidates are from multiple Robo-AO observing runs on the Palomar Observatory 1.5m telescope, spanning 2012 July to September, 2013 April to October, 2014 June to September, and 2015 June. Observations were in either Sloan-i or a long-pass 600nm (LP600) filter, the latter being similar to the Kepler-bandpass when combined with the EMCCD's quantum efficiency curve for red/cool stars. The near-infrared observations are from the Near-InfraRed Camera 2 (NIRC2) instrument on the 10m Keck II telescope, conducted on 2013 June 24, August 24 and 25, 2014 August 17, 2015 July 25, and August 4 in the J, H, K, and/or Kp filters in the narrow mode of NIRC2 (9.952mas/pixel). The relative positions and raw contrast measurements of imaged companions are presented in Table4. The reduced apparent magnitudes, which use both measured contrasts and canonical apparent magnitudes of combined systems in Kepler literature, are presented in Table5. (5 data files).

  20. High spatial resolution infrared imaging of L1551-IRS 5 - Direct observations of its circumstellar envelope

    NASA Technical Reports Server (NTRS)

    Moneti, Andrea; Forrest, William J.; Pipher, Judith L.; Woodward, Charles E.

    1988-01-01

    Images of L1551-IRS 5 were obtained at 1.65, 2.2, and 3.8 microns using the University of Rochester's Infrared Array Camera. It is found that IRS 5 is spatially resolved, and that it is elongated: the observed FWHM size of IRS 5 is 4.1 x 2.8 arcsec-squared at 2.2 microns. These observations are interpreted in terms of a flattened circumstellar envelope that is viewed from about 18 deg above its equatorial plane, a configuration that has been treated theoretically by Lefevre et al. In this model the central star is not seen directly, but only light scattered toward the observer from the visible polar region, where the envelope is thinnest, is observed. It is deduced that the envelope has a diameter of 1000 AU, a molecular hydrogen density of greater than or approximately equal to 4 x 10 to the 6th/cu cm, and a mass of greater than or approximately equal to 0.02 M solar mass, which results in an extinction of Av greater than about 33 mag to the central source.

  1. Infrared Cloudy Radiative Transfer Validation Using Coincident AIRS and MODIS Observations

    NASA Astrophysics Data System (ADS)

    Fishbein, E.; Schreier, M. M.; Wilson, R. C.; Yue, Q.; Kahn, B. H.

    2016-12-01

    Modeling observed cloudy radiances of satellite-based infrared sounders is challenging because of scene heterogeneity. Comparisons of observed and calculated AIRS radiances are conditioned against cloud statistics from the MODIS cloud products to characterize the accuracy of the radiative transfer and its dependence of scene complexity. Radiances are calculated with the SARTA fast radiative transfer algorithm using atmospheric temperature, water vapor and ozone profiles from the ECMWF operational forecast, but cloud fields from the ECMWF forecasts, and AIRS L2 and MODIS L2 observational products. The error arising from differences in cloud representations and their translations to input to the radiative transfer models is discussed in the first half of the presentation, while the latter half deals with the treatment of scene heterogeneity and the error this adds to the modeled radiances. Calculated radiances smoothed over an AIRS footprint from high spatial atmospheric states are compared with radiances from smoothed states and observed radiances. The goal of this study is to quantify the improvement in cloudy radiative transfer modeling when external information about scene complexity is applied.

  2. Hurricane Frances as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS) - Total Water

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Born in the Atlantic, Hurricane Frances became a category 4 hurricane on August 31, 2004. Expectations are the hurricane will hit the Space Coast of Florida in Brevard County early Sunday morning.

    This movie is a time-series of maps that show AIRS observations of the total amount of water vapor present in the atmospheric column above each point of the Earth's surface. If all the water vapor in the column were forced to fall as rain, the depth of the resulting puddle on the surface at that point is equal to the value shown on the map. Fifty millimeters (mm) is about 2 inches. The large band of maximum water vapor in the neighborhood of the equator is the Intertropical Convergence Zone (ITCZ), a region of strong convection and powerful thunderstorms.

    This movie shows the total precipitable water vapor from August 23 through September 2, 2004. You can see Hurricane Frances as it moves through the Caribbean toward Florida, and the changes in intensity are visible. The eye has been marked with a red spot. The water vapor encompassed by the hurricane is also the result of the very strong convection which is an integral part of the formation and intensification of tropical storms. If you look at the last frame of the movie in the lower right corner, you can see the emergence of a new tropical storm. Ivan makes its debut in the Atlantic.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft

  3. Hurricane Frances as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS) - Total Water

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Born in the Atlantic, Hurricane Frances became a category 4 hurricane on August 31, 2004. Expectations are the hurricane will hit the Space Coast of Florida in Brevard County early Sunday morning.

    This movie is a time-series of maps that show AIRS observations of the total amount of water vapor present in the atmospheric column above each point of the Earth's surface. If all the water vapor in the column were forced to fall as rain, the depth of the resulting puddle on the surface at that point is equal to the value shown on the map. Fifty millimeters (mm) is about 2 inches. The large band of maximum water vapor in the neighborhood of the equator is the Intertropical Convergence Zone (ITCZ), a region of strong convection and powerful thunderstorms.

    This movie shows the total precipitable water vapor from August 23 through September 2, 2004. You can see Hurricane Frances as it moves through the Caribbean toward Florida, and the changes in intensity are visible. The eye has been marked with a red spot. The water vapor encompassed by the hurricane is also the result of the very strong convection which is an integral part of the formation and intensification of tropical storms. If you look at the last frame of the movie in the lower right corner, you can see the emergence of a new tropical storm. Ivan makes its debut in the Atlantic.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft

  4. An Interferometric Study of the Fomalhaut Inner Debris Disk. II. Keck Nuller Mid-infrared Observations

    NASA Astrophysics Data System (ADS)

    Mennesson, B.; Absil, O.; Lebreton, J.; Augereau, J.-C.; Serabyn, E.; Colavita, M. M.; Millan-Gabet, R.; Liu, W.; Hinz, P.; Thébault, P.

    2013-02-01

    We report on high-contrast mid-infrared observations of Fomalhaut obtained with the Keck Interferometer Nuller (KIN) showing a small resolved excess over the level expected from the stellar photosphere. The measured null excess has a mean value of 0.35% ± 0.10% between 8 and 11 μm and increases from 8 to 13 μm. Given the small field of view of the instrument, the source of this marginal excess must be contained within 2 AU of Fomalhaut. This result is reminiscent of previous VLTI K-band (sime2μm) observations, which implied the presence of a ~0.88% excess, and argued that thermal emission from hot dusty grains located within 6 AU from Fomalhaut was the most plausible explanation. Using a parametric two-dimensional radiative transfer code and a Bayesian analysis, we examine different dust disk structures to reproduce both the near- and mid-infrared data simultaneously. While not a definitive explanation of the hot excess of Fomalhaut, our model suggests that the most likely inner few AU disk geometry consists of a two-component structure, with two different and spatially distinct grain populations. The 2-11 μm data are consistent with an inner hot ring of very small (sime10-300 nm) carbon-rich grains concentrating around 0.1 AU. The second dust population—inferred from the KIN data at longer mid-infrared wavelengths—consists of larger grains (size of a few microns to a few tens of microns) located further out in a colder region where regular astronomical silicates could survive, with an inner edge around 0.4 AU-1 AU. From a dynamical point of view, the presence of the inner concentration of submicron-sized grains is surprising, as such grains should be expelled from the inner planetary system by radiation pressure within only a few years. This could either point to some inordinate replenishment rates (e.g., many grazing comets coming from an outer reservoir) or to the existence of some braking mechanism preventing the grains from moving out.

  5. Advanced fire observation by the Intelligent Infrared Sensor prototype FOCUS on the International Space Station

    NASA Astrophysics Data System (ADS)

    Oertel, D.; Haschberger, P.; Tank, V.; Lanzl, F.; Zhukov, B.; Jahn, H.; Briess, K.; Lorenz, E.; Roeser, H.-P.; Ginati, A.; Tobehn, C.; Schulte in den Bäumen, J.; Christmann, U.

    1999-01-01

    Current and planned operational space-borne Earth observation systems provide spatially, radiometrically or temporally crude data for the detection and monitoring of high temperature phenomena on the surface of our planet. High Temperature Events (HTE) very often cause environmental disasters. Such HTE are forest and savannah fires, fires of open coal mines, volcanic activities and others (e.g. fires of oil wells, pipelines etc.). A simultaneous co-registration of a combination of infrared (IR) and visible (VIS) channels is the key for a reliable autonomous on-board detection of High Temperature Events (HTE) on Earth surface, such as vegetation fires and volcano eruptions. This is the main feature of the FOCUS experiment. Furthermore there are ecology-oriented objectives of the FOCUS experiment mainly related to spectrometric/imaging remote inspection and parameter extraction of selected HTEs, and to the assessment of some ecological consequences of HTEs, such as aerosol and gas emission. Based on own experimental work and supported by Co-Investigators from Italy, Greece, France, Spain, Russia and Germany, DLR proposed in 1997 to use the International Space Station (ISS) in its early utilization phase as a platform and test-bed for an Intelligent Infrared Sensor prototype FOCUS of a future Environmental Disaster Recognition Satellite System. FOCUS is considered by ESA as an important mission combining a number of proven technologies and observation techniques to provide the scientific and operational user community with key data for the classification and monitoring of forest fires. FOCUS was selected as one of five European ``Groupings'' to be flown as an externally mounted payload during the early utilisation phase of the ISS. The FOCUS Phase A Study will be performed by OHB-System, DLR and Zeiss from September 1998 until May 1999.

  6. Mid-Infrared Observational and Theoretical Studies of Star Formation and Early Solar Systems

    NASA Technical Reports Server (NTRS)

    Jones, Barbara

    1997-01-01

    The first 2 years of this program were used to make mid-IR observations of regions of star formation in the Orion nebula with the UCSD mid-IR camera at the UCSD/University of Minnesota telescope at Mt. Lemmon. These observations attempted to make the first systematic study of an extended region, known to have newly forming stars, and expected to have complex mid-IR emission. We discovered, to our surprise, that most of the thermal emission originated from extended sources rather than from point sources. This interesting observation made the analysis of the data much more complex, since the chop/nod procedures used at these wavelengths produce a differential measurement of the emission in one region compared to that in the adjacent region. Disentangling complex extended emission in such a situation is very difficult. In parallel with this work we were also observing comets in the thermal infrared, the other component of the original proposal. Some spectacular data on the comet Swift-Tuttle was acquired and published. A changing jet structure observed over a 2 week period is described. The rotation period of the comet can be measured at 66 hours. The size of the nucleus can also be estimated (at 30 km) from the observed excess flux from the nucleus. These data have lead to the development of models describing the action of dust particles of differing sizes and composition leaving the nucleus. The spatial distribution of the predicted IR emission has been compared to the observed jet structures, leading to estimates of both particles sizes, relative amounts of silicate vs organic grains, and the amounts of dust emitted in the jets vs isotopic emission.

  7. Titan's lakes and Mare observed by the Visual and Infrared Mapping Spectrometer

    NASA Astrophysics Data System (ADS)

    Brown, R. H.; Soderblom, L. A.; Sotin, C.; Barnes, J. W.; Hayes, A. G.; Lawrence, K. J.; Le Mouelic, S.; Rodriguez, S.; Soderblom, J. M.; Baines, K. H.; Buratti, B. J.; Clark, R. N.; Jaumann, R.; Nicholson, P. D.; Stephan, K.

    2012-04-01

    Titan is the only place, besides Earth, that holds stable liquid bodies at its surface. The large Kraken Mare, first seen by ISS [1], was then observed by the radar instrument that discovered a large number of small lakes as well as two other Mare [2]. The liquid nature of these radar-dark features was later confirmed by the specular reflection observed by the Visual and Infrared Mapping Spectrometer (VIMS) over Kraken Mare [3] and by the very low albedo at 5-micron over Ontario Lacus [4]. The three largest lakes are called Mare and are all located in the North Pole area. It is remarkable that most of these lakes have been observed on the North Pole with only one large lake, Ontario lacus, located in the South Pole area. This observation suggests the influence of orbital parameters on the meteorology and the occurrence of rainfalls to refill the depressions [5]. Ethane was detected by the VIMS instrument as one component of Ontario lacus [4]. These lakes and Mare play a key role in Titan's meteorology as demonstrated by recent global circulation models [6]. Determining the composition and the evolution of those lakes has become a primary science objective of the Cassini extended mission. Since Titan entered northern spring in August 2009, the North Pole has been illuminated allowing observations at optical wavelengths. On June 5, 2010 the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft observed the northern pole area with a pixel size from 3 to 7 km. These observations demonstrate that little of the solar flux at 5-micron is scattered by the atmosphere, which allowed us to build a mosaic covering an area of more than 500,000 km2 that overlaps and complements observations made by the Synthetic Aperture Radar (SAR) in 2007. We find that there is an excellent correlation between the shape of the radar dark area, known as Ligeia Mare and the VIMS 5-micron dark unit. Matching most of the radar shoreline, the 2010 VIMS observations suggest

  8. Finite-Horizon H∞ Consensus for Multiagent Systems With Redundant Channels via An Observer-Type Event-Triggered Scheme.

    PubMed

    Xu, Wenying; Wang, Zidong; Ho, Daniel W C

    2017-06-06

    This paper is concerned with the finite-horizon H∞ consensus problem for a class of discrete time-varying multiagent systems with external disturbances and missing measurements. To improve the communication reliability, redundant channels are introduced and the corresponding protocol is constructed for the information transmission over redundant channels. An event-triggered scheme is adopted to determine whether the information of agents should be transmitted to their neighbors. Subsequently, an observer-type event-triggered control protocol is proposed based on the latest received neighbors' information. The purpose of the addressed problem is to design a time-varying controller based on the observed information to achieve the H∞ consensus performance in a finite horizon. By utilizing a constrained recursive Riccati difference equation approach, some sufficient conditions are obtained to guarantee the H∞ consensus performance, and the controller parameters are also designed. Finally, a numerical example is provided to demonstrate the desired reliability of redundant channels and the effectiveness of the event-triggered control protocol.

  9. Spatially resolved near infrared observations of Enceladus' tiger stripe eruptions from Cassini VIMS

    NASA Astrophysics Data System (ADS)

    Dhingra, Deepak; Hedman, Matthew M.; Clark, Roger N.; Nicholson, Philip D.

    2017-08-01

    Particle properties of individual fissure eruptions within Enceladus' plume have been analyzed using high spatial resolution Visible and Infrared Mapping Spectrometer (VIMS) observations from the Cassini mission. To first order, the spectra of the materials emerging from Cairo, Baghdad and Damascus sulci are very similar, with a strong absorption band around 3 μm due to water-ice. The band minimum position indicates that the ice grains emerging from all the fissures are predominantly crystalline, which implies that the water-ice particles' formation temperatures are likely above 130 K. However, there is also evidence for subtle variations in the material emerging from the different source fissures. Variations in the spectral slope between 1-2.5 μm are observed and probably reflect differences in the size distributions of particles between 0.5 and 5 μm in radius. We also note variations in the shape of the 3 μm water-ice absorption band, which are consistent with differences in the relative abundance of > 5 μm particles. These differences in the particle size distribution likely reflect variations in the particle formation conditions and/or their transport within the fissures. These observations therefore provide strong motivation for detailed modeling to help place important constraints on the diversity of the sub-surface environmental conditions at the geologically active south-pole of Enceladus.

  10. Observations of Ice Nucleation and Propagation in Plants Using Infrared Video Thermography.

    PubMed Central

    Wisniewski, M.; Lindow, S. E.; Ashworth, E. N.

    1997-01-01

    We evaluated the use of infrared (IR) video thermography to observe directly ice nucleation and propagation in plants. An imaging radiometer with an HgCdTe long-wave (8-12 [mu]m) detector was utilized to image the thermal response of plants during freezing. IR images were analyzed in real time and recorded on videotape. Information on the videotape was subsequently accessed and analyzed utilizing IR image analysis software. Freezing of water droplets as small as 0.5 [mu]L was clearly detectable with the radiometer. Additionally, a comparison of temperature tracking data collected by the radiometer with data collected with thermocouples showed close correspondence. Monitoring of an array of plant species under different freezing conditions revealed that ice nucleation and propagation are readily observable by thermal imaging. In many instances, the ice nucleation-active bacterium Pseudomonas syringae placed on test plants could be seen to initiate freezing of the whole plant. Apparent ice nucleation by intrinsic nucleators, despite the presence of ice nucleation-active bacteria, was also evident in some species. Floral bud tissues of peach (Prunus persica) could be seen to supercool below the temperature of stem tissues, and ice nucleation at the site of insertion of the thermocouple was frequently observed. Rates of propagation of ice in different tissues were also easily measured by thermal imaging. This study demonstrates that IR thermography is an excellent method for studying ice nucleation and propagation in plants. PMID:12223611

  11. Apache Point Observatory's All-Sky Camera: Observing Clouds in the Thermal Infrared

    NASA Astrophysics Data System (ADS)

    Anderson, K. S. J.; Brinkmann, J.; Carr, M.; Woods, D.; Finkbeiner, D. P.; Gunn, J. E.; Loomis, C. L.; Schlegel, D.; Snedden, S.

    2002-12-01

    Cloud cover at Apache Point Observatory is monitored by an all-sky camera system which images clouds in the thermal infrared. Even thin clouds, illuminated by thermal emission from the ground, can be detected. These same clouds are almost invisible at visual wavelengths, especially on moonless nights at this dark-sky observatory site. Our camera system uses an aluminum hyperboloidal mirror to provide a wide-angle view covering most of the sky; it is sensitive to radiation in the 8 to 12 micron wavelength interval. A cloud free atmosphere is fairly transparent in this window; clouds appear as bright structures against the darker sky background. Images are recorded at video rates, then summed and averaged in software to increase system sensitivity. Current all-sky images are available to on-site observers or through the Apache Point Observatory web pages. Cloud information is used to plan observing, make real-time observing decisions, and can provide useful estimates of atmospheric extinction and sky brightness at other wavelengths.

  12. High-Resolution Infrared Spectroscopic Observations of the Upper Scorpius Eclipsing Binary EPIC 203868608

    NASA Astrophysics Data System (ADS)

    Johnson, Marshall C.; Mace, Gregory N.; Kim, Hwihyun; Kaplan, Kyle; McLane, Jacob; Sokal, Kimberly R.

    2017-06-01

    EPIC 203868608 is a source in the ~10 Myr old Upper Scorpius OB association. Using K2 photometry and ground-based follow-up observations, David et al. (2016) found that it consists of two brown dwarfs with a tertiary object at a projected separation of ~20 AU; the former objects appear to be a double-lined eclipsing binary with a period of 4.5 days. This is one of only two known eclipsing SB2s where both components are below the hydrogen-burning limit. We present additional follow-up observations of this system from the IGRINS high-resolution near-infrared spectrograph at McDonald Observatory. Our measured radial velocities do not follow the orbital solution presented by David et al. (2016). Instead, our combined IGRINS plus literature radial velocity dataset appears to indicate a period significantly different than that of the eclipsing binary obvious from the K2 light curve. We will discuss possible scenarios to account for the conflicting observations of this system.

  13. Measurement of evapotranspiration with combined reflective and thermal infrared radiance observations

    NASA Technical Reports Server (NTRS)

    Hope, Allen S.

    1993-01-01

    The broad goal of the research summarized in this report was 'To facilitate the evaluation of regional evapotranspiration (ET) through the combined use of solar reflective and thermal infrared radiance observations.' The specific objectives stated by Goward and Hope (1986) were to: (1) investigate the nature of the relationship between surface temperature (T(sub S)) and the normalized difference vegetation index (NDVI) and develop an understanding of this relationship in terms of energy exchange processes, particularly latent flux heat (LE); (2) develop procedures to estimate large area LE using combined T(sub S) and NDVI observations obtained from AVHRR data; and (3) determine whether measurements derived from satellite observations relate directly to measurements made at the surface or from aircraft platforms. Both empirical and modeling studies were used to develop an understanding of the T(sub S)-NDVI relationship. Most of the modeling was based on the Tergra model as originally proposed by Goward. This model, and modified versions developed in this project, simulates the flows of water and energy in the soil-plant-atmosphere system using meteorological, soil and vegetation inputs. Model outputs are the diurnal course of soil moisture, T(sub S), LE and the other individual components of the surface energy balance.

  14. Value-added Impact from Future Geostationary Hyperspectral Infrared Sounder Observations on Hurricane Forecasts

    NASA Astrophysics Data System (ADS)

    Li, J.; Schmit, T. J.; Li, Z.; Zhu, F.; Lim, A.; Atlas, R. M.; John, P.

    2015-12-01

    Future geostationary (Geo) advanced InfraRed (IR) sounders have finer spatial, spectral, and temporal resolutions compared with the existing GOES sounders, providing much improved resolving power of atmospheric thermodynamic information. When quantitatively assessing the value-added impact from such instruments over the current sounding systems onboard the Low Earth Orbit (Leo) satellites, the real question is what is the optimal impact using the current assimilation/forecast systems. More specifically, will assimilation of more observations from Geo IR sounders with the current assimilation/forecast systems yield improved forecast as expected? And if so, how to assimilate the high temporal resolution Geo sounding information and what is the impact on forecasts? Taken tropical cyclone (TC) forecasting as an example, this study tries to address these questions through a quick regional Observing System Simulation Experiments (r-OSSE) study. The synthetic observations are simulated from the sample ECMWF T1279 nature run (NR) for Hurricane Sandy (2012), including RAOB, the Leo AIRS, and Geo AIRS. Various experiments were carried out using WRF 3.6.1 and GSI 3.3 to study the impact on Sandy track forecast. And the study shows that a) it is critical to assign an appropriate observational error (observation error covariance matrix - O matrix) in order to show improved positive impacts from Geo AIRS over Leo AIRS; b) cycling of 3/6-hourly shows improved positive impacts over none cycling, but hourly cycling does not show further improvement on forecasts among all experiments, and c) with thinning (120 ~ 240 km), the impacts have the following order: hourly > 3-hourly > 6-hourly > none cycling. These experiments indicate that while more observations may improve forecasts, much more observations are difficult to show further improvement with the current assimilation/forecast system configurations. There exists a tradeoff between the number of observations to be assimilated

  15. High resolution infrared astronomy satellite observations of a selected spiral galaxy

    NASA Technical Reports Server (NTRS)

    Kulkarni, S. R.

    1991-01-01

    The H I, infrared, CO, H alpha and H beta band observations of M51, the prototypical grand-design spiral galaxy, are used to study the consequences of star formation for the distribution of H I and dust. Using the new Very Large Array (VLA) map of 21 cm emission, the Owens Valley Radio Observatory CO mosaic map, and an H alpha imate, new tests were performed with the idea of Tilanus and Allen that the H I is largely a photodissociation product in star-forming regions. It is confirmed that the H I spiral arms are generally coincident with the H II region arms, and offset downstream from the CO arms. The radial distributions of total gas, H alpha and H I surface density have a simple explanation in the dissociation picture. The distributions also demonstrate how the surface density of H I might be related to the star formation efficiency in molecule-rich galaxies. The large width of the H I regions along the arms compared to that of the giant H II regions can be understood in terms of a simple calculation of the expected size of an H I region associated with a typical giant H II region. The longer lifetime of the stars producing dissociating radiation vs. those producing ionizing radiation and the relatively long molecular formation timescale will also contribute to the greater width of the H I arms if stars are continuously forming on the arms. The lack of detailed coincidence of the H I and H II regions along the inner arms has a variety of possible explanations. Two simple tests were performed to probe the origins of the IRAS emission in M51. First, it was found that the infrared excess (IFE) of M51 is 24, suggesting that a substantial fraction of the infrared emission arises from dust heated by photons which do not originate in massive star-formaing regions. Second, radial cuts through the IRAS bands show that at 12, 25, and 60 microns, the arm-interarm contrast of the IRAS emission is substantially less than that of the H alpha emission, providing further

  16. Infrared Radiative Forcing and Atmospheric Lifetimes of Trace Species Based on Observations from UARS

    NASA Technical Reports Server (NTRS)

    Minschwaner, K.; Carver, R. W.; Briegleb, B. P.

    1997-01-01

    Observations from instruments on the Upper Atmosphere Research Satellite (UARS) have been used to constrain calculations of infrared radiative forcing by CH4, CCl2F2 and N2O, and to determine lifetimes Of CCl2F2 and N2O- Radiative forcing is calculated as a change in net infrared flux at the tropopause that results from an increase in trace gas amount from pre-industrial (1750) to contemporary (1992) times. Latitudinal and seasonal variations are considered explicitly, using distributions of trace gases and temperature in the stratosphere from UARS measurements and seasonally averaged cloud statistics from the International Satellite Cloud Climatology Project. Top-of-atmosphere fluxes calculated for the contemporary period are in good agreement with satellite measurements from the Earth Radiation Budget Experiment. Globally averaged values of the radiative forcing are 0.536, 0.125, and 0.108 W m-2 for CH4, CCl2F2, and N2O, respectively. The largest forcing occurs near subtropical latitudes during summer, predominantly as a result of the combination of cloud-free skies and a high, cold tropopause. Clouds are found to play a significant role in regulating infrared forcing, reducing the magnitude of the forcing by 30-40% compared to the case of clear skies. The vertical profile of CCl2F2 is important in determining its radiative forcing; use of a height-independent mixing ratio in the stratosphere leads to an over prediction of the forcing by 10%. The impact of stratospheric profiles on radiative forcing by CH4 and N2O is less than 2%. UARS-based distributions of CCl2F2 and N2O are used also to determine global destruction rates and instantaneous lifetimes of these gases. Rates of photolytic destruction in the stratosphere are calculated using solar ultraviolet irradiances measured on UARS and a line-by-line model of absorption in the oxygen Schumann-Runge bands. Lifetimes are 114 +/- 22 and 118 +/- 25 years for CCl2F2 and N2O, respectively.

  17. Global trends in lake surface temperatures observed using multi-sensor thermal infrared imagery

    NASA Astrophysics Data System (ADS)

    Schneider, Philipp; Hook, Simon J.; Radocinski, Robert G.; Corlett, Gary K.; Hulley, Glynn C.; Schladow, S. Geoffrey; Steissberg, Todd E.

    2010-05-01

    Recent research has shown that the temperature of lakes and other inland water bodies does not only act as a good indicator of climate variability but under certain conditions can even increase more rapidly than the regional air temperature. Further investigation of this phenomenon in particular and of the interaction between lake temperature and climate variability in general requires extensive observations of lake temperature on a global scale. Current in situ records are limited in their spatial and/or temporal coverage and are thus insufficient for this task. However, a nearly 30-year archive of satellite-derived thermal infrared imagery from multiple sensors is available at this point and can be used to fill this data gap. We describe research on utilizing the existing archive of spaceborne thermal infrared imagery to generate multi-decadal time series of lake surface temperature for 170 of the largest lakes worldwide. The data used for this purpose includes imagery from the Advanced Very High Resolution Radiometers (AVHRR), the series of (Advanced) Along-Track Scanning Radiometers ((A)ATSR), and the Moderate Resolution Imaging Spectroradiometer (MODIS). Used in combination, these data sets offer a gapless time series of daily to near-daily thermal infrared retrievals from 1981 through present. In this contribution we demonstrate using comprehensive in situ data at Lake Tahoe, California/Nevada, that lake water surface temperature can be estimated using these sensors with an accuracy of up to 0.2 K. We further show that accurate continuous time series of water surface temperature can be derived from the data and that these time series can be used to detect significant trends in the temporal thermal behavior of lakes and other inland water bodies worldwide. Complementing our recent case study for lakes in California and Nevada for which a rapid increase in mean nighttime summertime lake surface temperatures of 0.11 K per year on average was found, we present

  18. Seven years of observations of mid-tropospheric CO 2 from the Atmospheric Infrared Sounder

    NASA Astrophysics Data System (ADS)

    Pagano, Thomas S.; Chahine, Moustafa T.; Olsen, Edward T.

    2011-09-01

    The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in the 3.7-15.4 μm spectral region with spectral resolving power of better than 1200. The AIRS was designed to measure temperature and water vapor profiles and cloud properties for improvement in weather forecast and improved parameterization of climate processes. Currently a subset of AIRS Level 1B Radiance Products is assimilated by NWP centers, resulting in significant forecast improvement. Scientists have also demonstrated accurate retrievals of minor gases from AIRS including carbon monoxide, methane, and ozone. The excellent sensitivity and stability of the AIRS instrument has recently allowed the AIRS team to successfully retrieve carbon dioxide (CO 2) concentrations in the mid-troposphere (8-10 km) with a horizontal resolution of 100 km and accuracy better than 2 ppm. The AIRS mid-tropospheric CO 2 yield is 15,000 measurements per 24-h period over land and ocean, day and night for clear and cloudy scenes. The AIRS CO 2 accuracy has been validated against a variety of mid-tropospheric aircraft measurements as well as upward looking interferometers. Findings from the AIRS data include higher than expected variability in the mid-troposphere, the presence of a seasonally variable belt of enhanced CO 2 in the southern hemisphere, and observations of impact of atmospheric dynamics on the CO 2 concentrations in the mid-troposphere including the effects of El Nino/La Nina and the Arctic polar vortex. The full mid-tropospheric AIRS CO 2 data set is now available at the NASA GES/DISC for the 8 year time span since AIRS became operational.

  19. CO Observations and Investigation of Triggered Star Formation toward the N10 Infrared Bubble and Surroundings

    NASA Astrophysics Data System (ADS)

    Gama, D. R. G.; Lepine, J. R. D.; Mendoza, E.; Wu, Y.; Yuan, J.

    2016-10-01

    We studied the environment of the dust bubble N10 in molecular emission. Infrared bubbles, first detected by the GLIMPSE survey at 8.0 μm, are ideal regions to investigate the effect of the expansion of the H ii region on its surroundings and the eventual triggering of star formation at its borders. In this work, we present a multi-wavelength study of N10. This bubble is especially interesting because infrared studies of the young stellar content suggest a scenario of ongoing star formation, possibly triggered on the edge of the H ii region. We carried out observations of 12CO(1-0) and 13CO(1-0) emission at PMO 13.7 m toward N10. We also analyzed the IR and sub-millimeter emission on this region and compare those different tracers to obtain a detailed view of the interaction between the expanding H ii region and the molecular gas. We also estimated the parameters of the denser cold dust condensation and the ionized gas inside the shell. Bright CO emission was detected and two molecular clumps were identified from which we have derived physical parameters. We also estimate the parameters for the densest cold dust condensation and for the ionized gas inside the shell. The comparison between the dynamical age of this region and the fragmentation timescale favors the “Radiation-Driven Implosion” mechanism of star formation. N10 is a case of particular interest with gas structures in a narrow frontier between the H ii region and surrounding molecular material, and with a range of ages of YSOs situated in the region, indicating triggered star formation.

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  1. Thermal features at Volcanoes in the cascade range, as observed by aerial infrared surveys

    USGS Publications Warehouse

    Moxham, R.M.

    1970-01-01

    There have been no substantial changes in the thermal patterns at the summit of Mount Rainier in the period September 1964-September 1966, within the detection limits of the infrared instrumentation. Some differences in radiance are attributed to differences in snow cover. The highest apparent temperature is at a snow-free area on the west flank of the summit cone, several hundred feet below the west crater rim. An anomaly at this site was recorded on both infrared surveys, but no prior reports of thermal activity here have been made by ground parties. Other anomalous thermal zones at the summit are on the northern quadrants of both crater rims. A very small, low-temperature fumarole reported on Mount Adams was not detected, nor were any other thermal manifestations recorded. One anomaly consisting of a close-spaced cluster of thermal spots was detected at The Boot on Mount St. Helens and corresponds to a known fumarole area. The only thermal feature seen on Mount Shasta is near the summit at a thermal spring that has been observed by many climbers. Two anomalies were found on the north flank of Lassen Peak. Thermal activity had not been previously reported at either site, though one is in a known solfatarized area. No ground investigation has been made at the other location. Much of the other thermal activity in the Lassen Peak area is in the northeast quadrant of Brokeoff Caldera. Most of these features are well documented in the literature; others not previously described are in fairly accessible areas and doubtless result from springs and fumaroles related to Brokeoff Caldera. ?? 1970 Stabilimento Tipografico Francesco Giannini & Figli.

  2. Thermal features at some Cascade volcanoes as observed by aerial infrared surveys

    USGS Publications Warehouse

    Moxham, R.M.

    1970-01-01

    There have been no substantial changes in the thermal patterns at the summit of Mount Rainier in the period September 1964–September 1966, within the detection limits of the infrared instrumentation. Some differences in radiance are attributed to differences in snow cover. The highest apparent temperature is at a snow-free area on the west flank of the summit cone, several hundred feet below the west crater rim. An anomaly at this site was recorded on both infrared surveys, but no prior reports of thermal activity here have been made by ground parties. Other anomalous thermal zones at the summit are on the northern quadrants of both crater rims. A very small, low-temperature fumarole reported on Mount Adams was not detected, nor were any other thermal manifestations recorded. One anomaly consisting of a close-spaced cluster of thermal spots was detected at The Boot on Mount St. Helens and corresponds to a known fumarole area. The only thermal feature seen on Mount Shasta is near the summit at a thermal spring that has been observed by many climbers. Two anomalies were found on the north flank of Lassen Peak. Thermal activity had not been previously reported at either site, though one is in a known solfatarized area. No ground investigation has been made at the other location. Much of the other thermal activity in the Lassen Peak area is in the northeast quadrant of Brokeoff Caldera. Most of these features are well documented in the literature; others not previously described are in fairly accessible areas and doubtless result from springs and fumaroles related to Brokeoff Caldera.

  3. Seven Years of Observations of Mid-Tropospheric CO2 from the Atmospheric Infrared Sounder

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Chahine, Moustafa T.; Olsen, Edward T.

    2010-01-01

    The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in the 3.7-15.4 um spectral region with spectral resolution of better than 1200. The AIRS was designed to measure temperature and water vapor profiles and cloud properties for improvement in weather forecast and improved parameterization of climate processes. Currently the AIRS Level 1B Radiance Products are assimilated by NWP centers and have shown considerable forecast improvement. Scientists have also demonstrated accurate retrievals of minor gases from AIRS including Carbon Monoxide, Methane, and Ozone. The excellent sensitivity and stability of the AIRS instrument has recently allowed the AIRS team to successfully retrieve Carbon Dioxide (CO2) concentrations in the mid-troposphere (8-10 km) with a horizontal resolution of 100 km and accuracy of 1-2 ppm. The AIRS retrieves over 15,000 measurements per day and can achieve full global coverage in 30 days. The AIRS CO2 accuracy has been validated against a variety of aircraft measurements in the mid-troposphere and upward looking interferometers. Findings from the AIRS data include higher than expected variability in the mid-troposphere, the presence of a belt of CO2 in the southern hemisphere, and numerous observations of atmospheric circulation including the effects of El Nino/La Nina on the CO2 concentrations in the mid-troposphere. The full mid-tropospheric AIRS CO2 data set is now available at the NASA GES/DISC for almost eight years since AIRS has been operational.

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  5. Finite Element Modeling of Ground Deformation and Gravity Data Observed at Mt Etna During the 1993-1997 Inflation Phase

    NASA Astrophysics Data System (ADS)

    Ganci, G.; Currenti, G.; Del Negro, C.

    2006-12-01

    Elastic finite element models are applied to investigate the effects of topography and medium heterogeneities on the surface deformation and the gravity field produced by volcanic pressure sources. Changes in the gravity field cannot be interpreted only in terms of gain of mass disregarding the deformations of the rocks surrounding the source. Contributions to gravity variations depend also on surface and subsurface mass redistribution driven by dilation of the volcanic source. Both ground deformation and gravity changes were firstly evaluated by solving a coupled axial symmetric problem to estimate the effects of topography and medium heterogeneities. Numerical results show significant discrepancies in the ground deformation and gravity field compared to those predicted by analytical solutions, which disregard topography, elastic heterogeneities and density subsurface structures. With this in mind, we reviewed the expected gravity changes accompanying the 1993- 1997 inflation phase on Mt Etna by setting up a fully 3D finite element model in which we used the real topography of Etna volcano to include the geometry and seismic tomography data to infer crustal heterogeneities. The inflation phase was clearly detected by different geodetic techniques (EDM, GPS, SAR and leveling data) that showed a uniform expansion of the overall volcano edifice. When the gravity data are integrated with ground deformation data and a coupled modeling is solved, a mass intrusion is expected at depth to justify both ground deformation and gravity observation. Our findings highlighted two main points. Firstly, geodetic and gravity data, which independently reflect the state of volcano, need to be jointly modeled in order to obtain a reliable estimate of the depth and density of the intrusion. Secondly, the application of finite element methods allows for a more accurate modeling procedure, which might provide sensible insight into volcanic source definition.

  6. X-ray, radio, and infrared observations of the 'rapid burster' /MXB 1730-335/ during 1979 and 1980

    NASA Technical Reports Server (NTRS)

    Lawrence, A.; Cominsky, L.; Lewin, W. H. G.; Oda, M.; Ogawara, Y.; Inoue, H.; Koyama, K.; Makishima, K.; Matsuoka, M.; Murakami, T.

    1983-01-01

    The paper reports partially simultaneous observations of the 'rapid burster' (MXB 1730-335) at X-ray, infrared, and radio wavelengths, covering several hundred hours during 1979 and 1980. None of the authors of this report saw any infrared or radio bursts. On several occasions an absence of infrared bursting was observed during X-ray bursting. On one occasion an absence of X-ray bursting was observed during a radio burst (4.1 GHz) reported by Calla et al. (1979). To date, radio bursts (a total of at least a dozen) have been reported only by Calla et al. (1980). Considering these and other observations summarized here, the reported radio bursts are either unreal or do not bear a simple relation to the X-ray bursts from the 'rapid burster'. The status of the reported infrared bursts also remain ambiguous. Limits to the brightness of any persistent radio source at the position of MXB 1730-335, limits to persistent X-ray emission during an extended X-ray quiet phase, and a measurement of the infrared polarization in the direction of the X-ray source are also reported.

  7. X-ray, radio, and infrared observations of the 'rapid burster' /MXB 1730-335/ during 1979 and 1980

    NASA Technical Reports Server (NTRS)

    Lawrence, A.; Cominsky, L.; Lewin, W. H. G.; Oda, M.; Ogawara, Y.; Inoue, H.; Koyama, K.; Makishima, K.; Matsuoka, M.; Murakami, T.

    1983-01-01

    The paper reports partially simultaneous observations of the 'rapid burster' (MXB 1730-335) at X-ray, infrared, and radio wavelengths, covering several hundred hours during 1979 and 1980. None of the authors of this report saw any infrared or radio bursts. On several occasions an absence of infrared bursting was observed during X-ray bursting. On one occasion an absence of X-ray bursting was observed during a radio burst (4.1 GHz) reported by Calla et al. (1979). To date, radio bursts (a total of at least a dozen) have been reported only by Calla et al. (1980). Considering these and other observations summarized here, the reported radio bursts are either unreal or do not bear a simple relation to the X-ray bursts from the 'rapid burster'. The status of the reported infrared bursts also remain ambiguous. Limits to the brightness of any persistent radio source at the position of MXB 1730-335, limits to persistent X-ray emission during an extended X-ray quiet phase, and a measurement of the infrared polarization in the direction of the X-ray source are also reported.

  8. X-ray, radio, and infrared observations of the ''Rapid Burster'' (MXB 1730-335) during 1979 and 1980

    SciTech Connect

    Lawrence, A.; Cominsky, L.; Lewin, W.H.G.

    1983-04-01

    We report partially simultaneous observations of the ''rapid burster'' (MXB 1730--335) at X-ray, infrared, and radio wavelengths, covering several hundred hours during 1979 and 1980. None of the authors of this report saw any infrared or radio bursts. On several occasions we observed an absence of infrared bursting during X-ray bursting. On one occasion we observed an absence of X-ray bursting during a radio burst (4.1 GHz) reported by Calla et al. To date, radio bursts (a total of at least a dozen) have been reported only by Calla et al. Considering our null observations, and others summarized here, the reported radio bursts are either unreal or do not bear a simple relation to the X-ray bursts from the ''rapid burster.'' The status of the reported infrared bursts also remains ambiguous. We also report limits to the brightness of any persistent radio source at the position of MXB 1730--335, limit to persistent X-ray emission during an extended X-ray quiet phase, and a measurement of the infrared polarization in the direction of the X-ray source.

  9. Development of infrared Echelle spectrograph and mid-infrared heterodyne spectrometer on a small telescope at Haleakala, Hawaii for planetary observation

    NASA Astrophysics Data System (ADS)

    Sakanoi, Takeshi; Kasaba, Yasumasa; Kagitani, Masato; Nakagawa, Hiromu; Kuhn, Jeff; Okano, Shoichi

    2014-08-01

    We report the development of infrared Echelle spectrograph covering 1 - 4 micron and mid-infrared heterodyne spectrometer around 10 micron installed on the 60-cm telescope at the summit of Haleakala, Hawaii (alt.=3000m). It is essential to carry out continuous measurement of planetary atmosphere, such as the Jovian infrared aurora and the volcanoes on Jovian satellite Io, to understand its time and spatial variations. A compact and easy-to-use high resolution infrared spectrometer provide the good opportunity to investigate these objects continuously. We are developing an Echelle spectrograph called ESPRIT: Echelle Spectrograph for Planetary Research In Tohoku university. The main target of ESPRIT is to measure the Jovian H3+ fundamental line at 3.9 micron, and H2 nu=1 at 2.1 micron. The 256x256 pixel CRC463 InSb array is used. An appropriate Echelle grating is selected to optimize at 3.9 micron and 2.1 micron for the Jovian infrared auroral observations. The pixel scale corresponds to the atmospheric seeing (0.3 arcsec/pixel). This spectrograph is characterized by a long slit field-of-view of ~ 50 arcsec with a spectral resolution is over 20,000. In addition, we recently developed a heterodyne spectrometer called MILAHI on the 60 cm telescope. MILAHI is characterized by super high-resolving power (more than 1,500,000) covering from 7 - 13 microns. Its sensitivity is 2400 K at 9.6 micron with a MCT photo diode detector of which bandwidth of 3000 MHz. ESPRIT and MILAHI is planned to be installed on 60 cm telescope is planned in 2014.

  10. Thunderstorm top structure observed by aircraft overflights with an infrared radiometer

    NASA Technical Reports Server (NTRS)

    Adler, R. F.; Shenk, W. E.; Markus, M. J.; Fenn, D. D.; Szejwach, G.

    1983-01-01

    Thunderstorm top structure is examined with high spatial resolution radiometric data (visible and infrared) from aircraft overflights together with other storm views, including geosynchronous satellite observations. Results show that overshooting cumuliform towers appear as distinct cold areas in the high resolution, 11-micron IR aircraft images, but that the geosynchronous satellite observations significantly overestimate the thunderstorm-top IR brightness temperature, T(B), due to field of view effects. Profiles of cloud top height and T(B) across overshooting features indicate an adiabatic cloud surface lapse rate. However, one-dimensional cloud model results indicate that when comparing thunderstorm top temperature and height at different times or different storms, a temperature-to-height conversion of about 7 K/km is appropriate. Examination of mature storm evolution indicates that, during periods when the updraft is relatively intense, the satellite IR 'cold point' is aligned with the low-level radar reflectivity maximum, but during periods of updraft weakening and lowering cloud top heights, the satellite T(B) minimum occurs downwind with cirrus anvil debris. The growth period of a relatively weak cumulonimbus cluster is also examined with aircraft and satellite data.

  11. Skylab near-infrared observations of clouds indicating supercooled liquid water droplets

    NASA Technical Reports Server (NTRS)

    Curran, R. J.; Wu, M.-L. C.

    1982-01-01

    Orographically-induced lee-wave clouds were observed over New Mexico by a multichannel scanning radiometer on Skylab during December 1973. Channels centered at 0.83, 1.61 and 2.125 microns were used to determine the cloud optical thickness, thermodynamic phase and effective particle size. An additional channel centered at 11.4 microns was used to determine cloud-top temperature, which was corroborated through comparison with the stereographically determined cloud top altitudes and conventional temperature soundings. Analysis of the measured near-infrared reflection functions at 1.61 and 2.125 microns are most easily interpreted as indicating the presence of liquid-phase water droplets. This interpretation is not conclusive even after considerable effort to understand possible sources for misinterpretation. However, if accepted the resulting phase determination is considered anomalous due to the inferred cloud-top temperatures being in the -32 to -47 C range. Theory for the homogeneous nucleation of pure supercooled liquid water droplets predicts very short lifetimes for the liquid phase at these cold temperatures. A possible explanation for the observations is that the wave-clouds are composed of solution droplets. Impurities in the cloud droplets could decrease the homogeneous freezing rate for these droplets, permitting them to exist for a longer time in the liquid phase, at the cold temperatures found.

  12. Lunar Crater Ejecta: Physical Properties Revealed by Radar and Thermal Infrared Observations

    NASA Technical Reports Server (NTRS)

    Ghent, R. R.; Carter, L. M.; Bandfield, J. L.; Udovicic, C. J. Tai; Campbell, B. A.

    2015-01-01

    We investigate the physical properties, and changes through time, of lunar impact ejecta using radar and thermal infrared data. We use data from two instruments on the Lunar Reconnaissance Orbiter (LRO) - the Diviner thermal radiometer and the Miniature Radio Frequency (Mini-RF) radar instrument - together with Earth-based radar observations. We use this multiwavelength intercomparison to constrain block sizes and to distinguish surface from buried rocks in proximal ejecta deposits. We find that radar-detectable rocks buried within the upper meter of regolith can remain undisturbed by surface processes such as micrometeorite bombardment for greater than 3 Gyr. We also investigate the thermophysical properties of radar-dark haloes, comprised of fine-grained, rock-poor ejecta distal to the blocky proximal ejecta. Using Diviner data, we confirm that the halo material is depleted in surface rocks, but show that it is otherwise thermophysically indistinct from background regolith. We also find that radar-dark haloes, like the blocky ejecta, remain visible in radar observations for craters with ages greater than 3 Ga, indicating that regolith overturn processes cannot replenish their block populations on that timescale.

  13. Properties of Small Dark Features Observed in the Pure Near-Infrared and Visible Continua

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Cao, Wenda; Ma, Jun; Hartkorn, Klaus; Jing, Ju; Denker, Carsten; Wang, Haimin

    2005-08-01

    High-resolution images in the visible and near-infrared (NIR) continua at around 1560 nm were obtained of solar active regions NOAA AR 10707 and AR 10486 with the Dunn Solar Telescope (DST) at the National Solar Observatory/Sacramento Peak (NSO/SP) on 2004 December 1 and 2 and 2003 October 29. The images were taken with the high-order adaptive optics (HOAO) system, and the spatial resolution was close to the diffraction limit of the 76 cm aperture DST in both wavelengths. For the 2004 December run, the NIR observations were made with a newly developed Lyot filter system, which was designed at the Center for Solar-Terrestrial Research (CSTR)/New Jersey Institute of Technology (NJIT). The filter has a bandpass of 2.5 Å that allows us to observe the pure NIR continuum at the opacity minimum. Our data show that all dark features in the NIR are also dark in the visible light. There is no evidence showing the existence of so-called dark faculae, i.e., faculae that have negative contrasts in the NIR but positive contrasts in the visible. The negative peak contrasts of these small pores are about 50% in the visible and 25% in the NIR, and their dimensions are in the range of 1"-4".

  14. Near-infrared emission-line and continuum observations from the 1991 eclipse

    NASA Astrophysics Data System (ADS)

    Penn, M. J.; Arnaud, J.; Mickey, D. L.; Labonte, B. J.

    1994-11-01

    We report observations made during the 1991 July 11 total solar eclipse from the University of Hawaii 61 cm south telescope on the summit of Mauna Kea, Hawaii. The eclipse observations entail CCD imaging of a coronal region on the southeast limb of the Sun using four wavelength channels isolated with narrowband interference filters. We obtain two long exposure images in each channel including the continuum (lambda = 10690 A), the two near-infrared (Fe XIII) emission lines (lambda = 10747, 10798 A), and the He I line (lambda = 10830 A). We calibrate the images to the center-of-disk solar intensity. The (Fe XIII) images are the first coronal images published from these emission lines. We find significant structural differences between the line and continuum images implying large temperature gradients in our small field of view. We compute the line ratio of the two (Fe XIII) emission lines (R) and find that the ratio is within the limits 1.2 greater than or = R greater than or = 15.0. We examine the motion seen in the prominence structure and find transverse velocities of up to about 30 km/s. Finally we see no cold coronal emission to a limit of 2 x 10-7 solar BETA.

  15. Skylab near-infrared observations of clouds indicating supercooled liquid water droplets

    NASA Technical Reports Server (NTRS)

    Curran, R. J.; Wu, M.-L. C.

    1982-01-01

    Orographically-induced lee-wave clouds were observed over New Mexico by a multichannel scanning radiometer on Skylab during December 1973. Channels centered at 0.83, 1.61 and 2.125 microns were used to determine the cloud optical thickness, thermodynamic phase and effective particle size. An additional channel centered at 11.4 microns was used to determine cloud-top temperature, which was corroborated through comparison with the stereographically determined cloud top altitudes and conventional temperature soundings. Analysis of the measured near-infrared reflection functions at 1.61 and 2.125 microns are most easily interpreted as indicating the presence of liquid-phase water droplets. This interpretation is not conclusive even after considerable effort to understand possible sources for misinterpretation. However, if accepted the resulting phase determination is considered anomalous due to the inferred cloud-top temperatures being in the -32 to -47 C range. Theory for the homogeneous nucleation of pure supercooled liquid water droplets predicts very short lifetimes for the liquid phase at these cold temperatures. A possible explanation for the observations is that the wave-clouds are composed of solution droplets. Impurities in the cloud droplets could decrease the homogeneous freezing rate for these droplets, permitting them to exist for a longer time in the liquid phase, at the cold temperatures found.

  16. Observational Studies of Pre-Stellar Cores and Infrared Dark Clouds

    NASA Astrophysics Data System (ADS)

    Caselli, Paola

    2011-12-01

    Stars like our Sun and planets like our Earth form in dense regions within interstellar molecular clouds, called pre-stellar cores (PSCs). PSCs provide the initial conditions in the process of star and planet formation. In the past 15 years, detailed observations of (low-mass) PSCs in nearby molecular cloud complexes have allowed us to find that they are cold (T < 10K) and quiescent (molecular line widths are close to thermal), with a chemistry profoundly affected by molecular freeze-out onto dust grains. In these conditions, deuterated molecules flourish, becoming the best tools to unveil the PSC physical and chemical structure. Despite their apparent simplicity, PSCs still offer puzzles to solve and they are far from being completely understood. For example, what is happening to the gas and dust in their nuclei (the future stellar cradles) is still a mystery that awaits for ALMA. Other important questions are: how do different environments and external conditions affect the PSC physical/chemical structure? Are PSCs in high-mass star forming regions similar to the well-known low-mass PSCs? Here I review observational and theoretical work on PSCs in nearby molecular cloud complexes and the ongoing search and study of massive PSCs embedded in infrared dark clouds (IRDCs), which host the initial conditions for stellar cluster and high-mass star formation.

  17. Five intermolecular vibrations of the CO2 dimer observed via infrared combination bands.

    PubMed

    Norooz Oliaee, J; Dehghany, M; Rezaei, Mojtaba; McKellar, A R W; Moazzen-Ahmadi, N

    2016-11-07

    The weakly bound van der Waals dimer (CO2)2 has long been of considerable theoretical and experimental interest. Here, we study its low frequency intermolecular vibrations by means of combination bands in the region of the CO2 monomer ν3 fundamental (≈2350 cm(-1)), which are observed using a tunable infrared laser to probe a pulsed supersonic slit jet expansion. With the help of a recent high level ab initio calculation by Wang, Carrington, and Dawes, four intermolecular frequencies are assigned: the in-plane disrotatory bend (22.26 cm(-1)); the out-of-plane torsion (23.24 cm(-1)); twice the disrotatory bend (31.51 cm(-1)); and the in-plane conrotatory bend (92.25 cm(-1)). The disrotatory bend and torsion, separated by only 0.98 cm(-1), are strongly mixed by Coriolis interactions. The disrotatory bend overtone is well behaved, but the conrotatory bend is highly perturbed and could not be well fitted. The latter perturbations could be due to tunneling effects, which have not previously been observed experimentally for CO2 dimer. A fifth combination band, located 1.3 cm(-1) below the conrotatory bend, remains unassigned.

  18. GLIMPSE Proper: Mid-Infrared Observations of Proper Motion and Variability Towards Galactic Center

    NASA Astrophysics Data System (ADS)

    Benjamin, Robert; Babler, Brian; Churchwell, Ed; Clarkson, Will; Kirkpatrick, Davy; Meade, Marilyn; Whitney, Barbara

    2015-10-01

    We propose to re-image 43.4 square degrees of the Galactic center to measure the proper motions of over fifteen million sources within 5 degrees of Galactic center over the last decade. This stellar sample will be over 20 times larger than the previous optical ground-based measurements and will allow us to constrain the anisotropic stellar velocity dispersion as a function of direction and distance as well as test previous claims of streaming motions associated with the near/far side of the Galactic bar, the X-shaped bar, and the vertically thin extended Long Bar. Not only will this be the largest Galactic bulge proper motion survey to date, it will also be the most uniform as mid-infrared observations are minimally affected by extinction over most of the region. We also expect to find at least 150 high proper motion stars (>100 mas/yr) which could be substellar objects and possible microlensing candidates against the crowded Galactic bulge. We will put constraints on the current production rate of hyper-velocity stars thought to be formed in binary interactions with the supermassive black hole of the Galaxy. Finally, we will be able to identify many new variable stars, particularly in the central 2x1.5 degree region of the Galaxy which has only been observed in a single epoch with Spitzer; we expect to find 1000 new sources with variability amplitudes greater than 0.2 mag.

  19. Lunar crater ejecta: Physical properties revealed by radar and thermal infrared observations

    NASA Astrophysics Data System (ADS)

    Ghent, R. R.; Carter, L. M.; Bandfield, J. L.; Tai Udovicic, C. J.; Campbell, B. A.

    2016-07-01

    We investigate the physical properties, and changes through time, of lunar impact ejecta using radar and thermal infrared data. We use data from two instruments on the Lunar Reconnaissance Orbiter (LRO) - the Diviner thermal radiometer and the Miniature Radio Frequency (Mini-RF) radar instrument - together with Earth-based radar observations. We use this multiwavelength intercomparison to constrain block sizes and to distinguish surface from buried rocks in proximal ejecta deposits. We find that radar-detectable rocks buried within the upper meter of regolith can remain undisturbed by surface processes such as micrometeorite bombardment for >3 Gyr. We also investigate the thermophysical properties of radar-dark haloes, comprised of fine-grained, rock-poor ejecta distal to the blocky proximal ejecta. Using Diviner data, we confirm that the halo material is depleted in surface rocks, but show that it is otherwise thermophysically indistinct from background regolith. We also find that radar-dark haloes, like the blocky ejecta, remain visible in radar observations for craters with ages >3 Ga, indicating that regolith overturn processes cannot replenish their block populations on that timescale.

  20. Five intermolecular vibrations of the CO2 dimer observed via infrared combination bands

    NASA Astrophysics Data System (ADS)

    Norooz Oliaee, J.; Dehghany, M.; Rezaei, Mojtaba; McKellar, A. R. W.; Moazzen-Ahmadi, N.

    2016-11-01

    The weakly bound van der Waals dimer (CO2)2 has long been of considerable theoretical and experimental interest. Here, we study its low frequency intermolecular vibrations by means of combination bands in the region of the CO2 monomer ν3 fundamental (≈2350 cm-1), which are observed using a tunable infrared laser to probe a pulsed supersonic slit jet expansion. With the help of a recent high level ab initio calculation by Wang, Carrington, and Dawes, four intermolecular frequencies are assigned: the in-plane disrotatory bend (22.26 cm-1); the out-of-plane torsion (23.24 cm-1); twice the disrotatory bend (31.51 cm-1); and the in-plane conrotatory bend (92.25 cm-1). The disrotatory bend and torsion, separated by only 0.98 cm-1, are strongly mixed by Coriolis interactions. The disrotatory bend overtone is well behaved, but the conrotatory bend is highly perturbed and could not be well fitted. The latter perturbations could be due to tunneling effects, which have not previously been observed experimentally for CO2 dimer. A fifth combination band, located 1.3 cm-1 below the conrotatory bend, remains unassigned.

  1. Observation requirements for the second generation EUMETSAT polar system visible/infrared imager

    NASA Astrophysics Data System (ADS)

    Phillips, P. L.; Schlüssel, P.; Accadia, C. J.; Banfi, S.; Zerfowski, I.

    2011-11-01

    The EUMETSAT Polar System Second Generation (EPS-SG) will continue operational meteorological measurements from polar orbiting satellites in the mid-morning orbit in the 2020 timeframe. The Metop Second Generation (Metop- SG) satellites will carry a payload which is primarily dedicated to operational meteorology and climate monitoring. A core mission within this payload is an optical imager required to meet the imagery user needs for Numerical Weather Prediction (NWP), Nowcasting (NWC) and climate applications. As NWP progresses towards operation on higher spatial resolution grids, improved representation of atmospheric processes encompassing the whole Earth system will be required, hence the availability of observations of clouds and aerosols as well as surface parameters will play an increasing role in a skilful weather forecast. Imagery data will also be very important in NWC applications, particularly in polar regions where space-borne imagery from geostationary satellites is not available. The EPS-SG Visible/Infrared Imaging mission (VII) follows on from an important list of predecessors such as the Advanced Very High Resolution Radiometer (AVHRR) and the Moderate resolution Imaging Spectro-radiometer (MODIS). The VII mission is planned to be implemented by the METimage instrument, developed by Deutsches Zentrum für Luft und Raumfahrt (DLR). METimage is a cross-purpose medium resolution, multi-spectral optical imager, measuring the optical spectrum of radiation emitted and reflected by the Earth from a low-altitude sun synchronous orbit over a minimum swath width of 2800 km. The spectral and radiometric performances and space-time resolution introduce novel observing capabilities that will enhance the observation potential compared to current operational optical imagers. These enhanced capabilities along with the evolution of the VII observation requirements are discussed.

  2. Infrared Observations with the 1.6 Meter New Solar Telescope in Big Bear: Origins of Space Weather

    DTIC Science & Technology

    2015-05-21

    solar storms, coronal mass ejections, solar activity, solar flares , New Solar Telescope, IRIM 16.  SECURITY CLASSIFICATION OF: 17.  LIMITATION OF...AFRL-OSR-VA-TR-2015-0125 Infrared Observations with the New Solar Telescope Philip Goode NEW JERSEY INST OF TECH NEWARK Final Report 05/21/2015...COVERED (From - To)      01-04-2012 to 31-03-2015 4.  TITLE AND SUBTITLE Infrared Observations with the 1.6 Meter New Solar Telescope in Big Bear: Origins

  3. Mars Infrared Spectroscopy: From Theory and the Laboratory To Field Observations

    NASA Technical Reports Server (NTRS)

    Kirkland, Laurel (Editor); Mustard, John (Editor); McAfee, John (Editor); Hapke, Bruce (Editor); Ramsey, Michael (Editor)

    2002-01-01

    The continuity and timely implementation of the Mars exploration strategy relies heavily on the ability of the planetary community to interpret infrared spectral data. However, the increasing mission rate, data volume, and data variety, combined with the small number of spectroscopists within the planetary community, will require a coordinated community effort for effective and timely interpretation of the newly acquired and planned data sets. Relevant spectroscopic instruments include the 1996 TES, 2001 THEMIS, 2003 Pancam, 2003 Mini-TES, 2003 Mars Express OMEGA, 2003 Mars Express PFS, and 2005 CFUSM. In light of that, leaders of the Mars spectral community met June 4-6 to address the question: What terrestrial theoretical, laboratory, and field studies are most needed to best support timely interpretations of current and planned visible infrared spectrometer data sets, in light of the Mars Program goals? A primary goal of the spectral community is to provide a reservoir of information to enhance and expand the exploration of Mars. Spectroscopy has a long history of providing the fundamental compositional discoveries in the solar system, from atmospheric constituents to surface mineralogy, from earth-based to spacecraft-based observations. However, such spectroscopic compositional discoveries, especially surface mineralogies, have usually come after long periods of detailed integration of remote observations, laboratory analyses, and field measurements. Spectroscopic information of surfaces is particularly complex and often is confounded by interference of broad, overlapping absorption features as well as confusing issues of mixtures, coatings, and grain size effects. Thus some spectroscopic compositional discoveries have come only after many years of research. However, we are entering an era of Mars exploration with missions carrying sophisticated spectrometers launching about every 2 years. It is critical that each mission provide answers to relevant questions

  4. Optical and infrared observations of the young SMC blob N26 and its environment

    NASA Astrophysics Data System (ADS)

    Testor, G.; Heydari-Malayeri, M.; Chen, C.-H. R.; Lemaire, J. L.; Sewiło, M.; Diana, S.

    2014-04-01

    Context. High-excitation compact H ii regions of the Magellanic Clouds are sites of recent massive star formation in low metallicity environments. Aims: Detailed study of these regions and their environments using high-spatial resolution observations is necessary to better understand massive star formation, which is still an unsolved problem. We aim at a detailed study of the Small Magellanic Cloud compact H ii region N26, which is only ~4'' in diameter. Methods: This study is based on high spatial resolution imaging (~0.̋1-0.̋3) in JHKs and L' bands, using the VLT equipped with the NAOS adaptive optics system. A larger region (~50 pc × 76 pc) was also imaged at medium spatial resolution, using the ESO 2.2 m telescope in optical wavelengths. We also used the JHKs archival data from the IRSF survey and the Spitzer Space Telescope SAGE-SMC survey. Results: Our high-resolution JHKs data of the compact high-excitation H ii region N26 reveal a new, bright component (C) between the two already known optical components A and B. Components A and C are resolved into several stars. Component A is the main ionization source of N26 and coincides with the radio continuum source B0046-7333. A new compact H ii region with very faint [O iii] λ5007 emission has been discovered. In the mid-infrared, our field resembles a shell formed by filaments and dust clumps, coinciding with the molecular cloud SMCB2. Region N22, located in the center of the shell, is the most excited H ii region of the complex and seems to have created a cavity in SMCB2. We derive nebular parameters from spectra, and using color-magnitude and color-color diagrams, we identify stellar sources that show significant near-infrared excess emission in order to identify the best YSO candidates. Based on observations obtained at the European Southern Observatory, El Paranal, Chile.Full Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc

  5. Multidirectional visible and shortwave infrared polarimeter for atmospheric aerosol and cloud observation: OSIRIS (Observing System Including PolaRisation in the Solar Infrared Spectrum)

    NASA Astrophysics Data System (ADS)

    Auriol, F.; Léon, J.-F.; Balois, J.-Y.; Verwaerde, C.; François, P.; Riedi, J.; Parol, F.; Waquet, F.; Tanré, D.; Goloub, P.

    2008-12-01

    The aim of this project is to improve the characterization of radiative and microphysical properties of aerosols and clouds in the atmosphere. These two atmospheric components and their interactions are among the main sources of uncertainty in the numerical forecast of climate change. In this context, we have designed a new airborne polarimeter for measuring directional, total and polarized radiances in the 440 to 2200 nm spectral range. This instrument is based on the POLDER concept, instrument that is currently aboard the PARASOL microsatellite. This new sensor consists in two optical systems for the visible to near infrared range (440 to 940 nm) and the shortwave infrared (940 to 2200 nm). Each optical system is composed of a wide field-of-view optics (114° and 105° respectively) associated to two rotating wheels for interferential filters and analysers respectively, and a 2D array of detectors. For each channel, the total and polarized radiances are computed using the measurements performed with the three analysers shifted by an angle of 60°. Thanks to the large field of view of the optics, any target is seen under several viewing angles during the aircraft motion. This type of instrument has been designed for the retrieval of optical thickness and microphysical properties of aerosols as well as for the determination of microphysical, macrophysical and radiative properties of clouds. In this paper, we will present this new instrument design and some preliminary results recently obtained during the first field campaign in May 2008 over Europe.

  6. Morphology, near-infrared luminosity, and mass of the Galactic bulge from COBE DIRBE observations

    NASA Technical Reports Server (NTRS)

    Dwek, E.; Arendt, R. G.; Hauser, M. G.; Kelsall, T.; Lisse, C. M.; Moseley, S. H.; Silverberg, R. F.; Sodroski, T. J.; Weiland, J. L.

    1995-01-01

    Near-infrared images of the Galactic bulge at 1.25, 2.2, 3.5, and 4.9 microns obtained by the Diffuse Infrared Background Experiment (DIRBE) onboard the Cosmic Background Explorer (COBE) satellite are used to characterize its morphology and to determine its infrared luminosity and mass. Earlier analysis of the DIRBE observations (Weiland et al. 1994) provided supporting evidence for the claim made by Blitz & Spergel (1991) that the bulge is bar-shaped with its near end in the first Galactic quadrant. Adopting various triaxial analytical functions to represent the volume emissivity of the source, we confirm the barlike nature of the bulge and show that triaxial Gaussian-type functions provide a better fit to the data than other classes of functions, including an axisymmetric spheroid. The introduction of a `boxy' geometry, such as the one used by Kent, Dame, & Fazio (1991) improves the fit to the data. Our results show that the bar is rotated in the plane with its near side in the first Galactic quadrant creating an angle of 20 deg +/- 10 deg between its major axis and the line of sight to the Galactic center. Typical axis ratios of the bar are (1:0.33 +/- 0.11:0.23 +/- 0.08), resembling the geometry of prolate spheroids. There is no statistically significant evidence for an out-of-plane tilt of the bar at 2.2 microns, and marginal evidence for a tilt of approximately equal 2 deg at 4.9 microns. The introduction of a roll around the intrinsic major axis of the bulge improves the `boxy' appearance of some functions. A simple integration of the observed projected intensity of the bulge gives a bulge luminosity of 1.2 x 10(exp 9), 4.1 x 10(exp 8), 2.3 x 10(exp 8), and 4.3 x 10(exp 7) solar luminosity, respectively, at 1.25, 2.2, 3.5, and 4.9 microns wavelength for a Galactocentric distance of 8.5 kpc. The 2.2 microns luminosity function of the bulge population in the direction of Baade's window yields a bolometric luminosity of L(sub bol) = 5.3 x 10(exp 9) solar

  7. Observation of two-photon photoemission from cesium telluride photocathodes excited by a near-infrared laser

    NASA Astrophysics Data System (ADS)

    Panuganti, H.; Piot, P.

    2017-02-01

    We explore the nonlinear photoemission in cesium telluride (Cs2Te) photocathodes where an ultrashort (˜100 fs full width at half max) 800-nm infrared laser is used as the drive-laser in lieu of the typical ˜266-nm ultraviolet laser. An important figure of merit for photocathodes, the quantum efficiency, we define here for nonlinear photoemission processes in order to compare with linear photoemission. The charge against drive-laser (infrared) energy is studied for different laser energy and intensity values and cross-compared with previously performed similar studies on copper [P. Musumeci et al., Phys. Rev. Lett. 104, 084801 (2010)], a metallic photocathode. We particularly observe two-photon photoemission in Cs2Te using the infrared laser in contrast to the anticipated three-photon process as observed for metallic photocathodes.

  8. Lower-tropospheric CO2 from near-infrared ACOS-GOSAT observations

    DOE PAGES

    Kulawik, Susan S.; O'Dell, Chris; Payne, Vivienne H.; ...

    2017-04-27

    We present two new products from near-infrared Greenhouse Gases Observing Satellite (GOSAT) observations: lowermost tropospheric (LMT, from 0 to 2.5 km) and upper tropospheric–stratospheric (U, above 2.5 km) carbon dioxide partial column mixing ratios. We compare these new products to aircraft profiles and remote surface flask measurements and find that the seasonal and year-to-year variations in the new partial column mixing ratios significantly improve upon the Atmospheric CO2 Observations from Space (ACOS) and GOSAT (ACOS-GOSAT) initial guess and/or a priori, with distinct patterns in the LMT and U seasonal cycles that match validation data. For land monthly averages, we findmore » errors of 1.9, 0.7, and 0.8 ppm for retrieved GOSAT LMT, U, and XCO2; for ocean monthly averages, we find errors of 0.7, 0.5, and 0.5 ppm for retrieved GOSAT LMT, U, and XCO2. In the southern hemispheric biomass burning season, the new partial columns show similar patterns to MODIS fire maps and MOPITT multispectral CO for both vertical levels, despite a flat ACOS-GOSAT prior, and a CO–CO2 emission factor comparable to published values. The difference of LMT and U, useful for evaluation of model transport error, has also been validated with a monthly average error of 0.8 (1.4) ppm for ocean (land). LMT is more locally influenced than U, meaning that local fluxes can now be better separated from CO2 transported from far away.« less

  9. Mid-J CO Shock Tracing Observations of Infrared Dark Clouds. III. SLED Fitting

    NASA Astrophysics Data System (ADS)

    Pon, A.; Kaufman, M. J.; Johnstone, D.; Caselli, P.; Fontani, F.; Butler, M. J.; Jiménez-Serra, I.; Palau, A.; Tan, J. C.

    2016-08-01

    Giant molecular clouds contain supersonic turbulence that can locally heat small fractions of gas to over 100 K. We run shock models for low-velocity, C-type shocks propagating into gas with densities between 103 and 105 cm-3 and find that CO lines are the most important cooling lines. Comparison to photodissociation region (PDR) models indicates that mid-J CO lines (J = 8 \\to 7 and higher) should be dominated by emission from shocked gas. In Papers I and II we presented CO J = 3 \\to 2, 8 \\to 7, and 9 \\to 8 observations toward four primarily quiescent clumps within infrared dark clouds. Here we fit PDR models to the combined spectral line energy distributions and show that the PDR models that best fit the low-J CO emission underpredict the mid-J CO emission by orders of magnitude, strongly hinting at a hot gas component within these clumps. The low-J CO data clearly show that the integrated intensities of both the CO J = 8 \\to 7 and 9 \\to 8 lines are anomalously high, such that the line ratio can be used to characterize the hot gas component. Shock models are reasonably consistent with the observed mid-J CO emission, with models with densities near {10}4.5 cm-3 providing the best agreement. Where this mid-J CO is detected, the mean volume filling factor of the hot gas is 0.1%. Much of the observed mid-J CO emission, however, is also associated with known protostars and may be due to protostellar feedback.

  10. Toward the Direct Measurement of Coronal Magnetic Fields: An Airborne Infrared Spectrometer for Eclipse Observations

    NASA Astrophysics Data System (ADS)

    Samra, J.; DeLuca, E. E.; Golub, L.; Cheimets, P.

    2014-12-01

    The solar magnetic field enables the heating of the corona and provides its underlying structure. Energy stored in coronal magnetic fields is released in flares and coronal mass ejections (CME) and provides the ultimate source of energy for space weather. Therefore, direct measurements of the coronal magnetic field have significant potential to enhance understanding of coronal dynamics and improve solar forecasting models. Of particular interest are observations of coronal field lines in the transitional region between closed and open flux systems, providing important information on the origin of the slow solar wind. While current instruments routinely observe only the photospheric and chromospheric magnetic fields, a proposed airborne spectrometer will take a step toward the direct observation of coronal fields by measuring plasma emission in the infrared at high spatial and spectral resolution. The targeted lines are four forbidden magnetic dipole transitions between 2 and 4 μm. The airborne system will consist of a telescope, grating spectrometer, and pointing/stabilization system to be flown on the NSF/NCAR High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) during the August 2017 total solar eclipse. The project incorporates several optical engineering challenges, centered around maintaining adequate spectral and spatial resolution in a compact and inexpensive package and on a moving platform. Design studies are currently underway to examine the tradeoffs between various optical geometries and control strategies for the pointing/stabilization system. The results will be presented and interpreted in terms of the consequences for the scientific questions. In addition, results from a laboratory prototype and simulations of the final system will be presented.

  11. Hard X-Ray Emission of the Luminous Infrared Galaxy NGC 6240 as Observed by Nustar

    NASA Technical Reports Server (NTRS)

    Puccetti, S.; Comastri, A.; Bauer, F. E.; Brandt, W. N.; Fiore, F.; Harrison, F. A.; Luo, B.; Stern, D.; Urry, C. M.; Alexander, D. M.; Annuar, A.; Arévalo, P.; Balokovic, M.; Boggs, S. E.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Gandhi, P.; Hailey, C. J.; Koss, M. J.; La Massa, S.; Marinucci, A.; Ricci, C.; Walton, D. J.; Zappacosta, L.; Zhang, W.

    2016-01-01

    We present a broadband (approx.0.3-70 keV) spectral and temporal analysis of NuSTAR observations of the luminous infrared galaxy NGC 6240 combined with archival Chandra, XMM-Newton, and BeppoSAX data. NGC 6240 is a galaxy in a relatively early merger state with two distinct nuclei separated by approx.1.5. Previous Chandra observations resolved the two nuclei and showed that they are both active and obscured by Compton-thick material. Although they cannot be resolved by NuSTAR, we were able to clearly detect, for the first time, both the primary and the reflection continuum components thanks to the unprecedented quality of the NuSTAR data at energies >10 keV. The NuSTAR hard X-ray spectrum is dominated by the primary continuum piercing through an absorbing column density which is mildly optically thick to Compton scattering (tau approx. = 1.2, NH approx. 1.5×10(exp 24)/sq cm. We detect moderately hard X-ray (>10 keV) flux variability up to 20% on short (15-20 ks) timescales. The amplitude of the variability is largest at approx..30 keV and is likely to originate from the primary continuum of the southern nucleus. Nevertheless, the mean hard X-ray flux on longer timescales (years) is relatively constant. Moreover, the two nuclei remain Compton-thick, although we find evidence of variability in the material along the line of sight with column densities NH < or = 2×10(exp 23)/sq cm over long (approx.3-15 yr) timescales. The observed X-ray emission in the NuSTAR energy range is fully consistent with the sum of the best-fit models of the spatially resolved Chandra spectra of the two nuclei.

  12. Hard X-Ray Emission of the Luminous Infrared Galaxy NGC 6240 as Observed by Nustar

    NASA Technical Reports Server (NTRS)

    Puccetti, S.; Comastri, A.; Bauer, F. E.; Brandt, W. N.; Fiore, F.; Harrison, F. A.; Luo, B.; Stern, D.; Urry, C. M.; Alexander, D. M.; hide

    2016-01-01

    We present a broadband (approx.0.3-70 keV) spectral and temporal analysis of NuSTAR observations of the luminous infrared galaxy NGC 6240 combined with archival Chandra, XMM-Newton, and BeppoSAX data. NGC 6240 is a galaxy in a relatively early merger state with two distinct nuclei separated by approx.1.5. Previous Chandra observations resolved the two nuclei and showed that they are both active and obscured by Compton-thick material. Although they cannot be resolved by NuSTAR, we were able to clearly detect, for the first time, both the primary and the reflection continuum components thanks to the unprecedented quality of the NuSTAR data at energies >10 keV. The NuSTAR hard X-ray spectrum is dominated by the primary continuum piercing through an absorbing column density which is mildly optically thick to Compton scattering (tau approx. = 1.2, NH approx. 1.5×10(exp 24)/sq cm. We detect moderately hard X-ray (>10 keV) flux variability up to 20% on short (15-20 ks) timescales. The amplitude of the variability is largest at approx..30 keV and is likely to originate from the primary continuum of the southern nucleus. Nevertheless, the mean hard X-ray flux on longer timescales (years) is relatively constant. Moreover, the two nuclei remain Compton-thick, although we find evidence of variability in the material along the line of sight with column densities NH < or = 2×10(exp 23)/sq cm over long (approx.3-15 yr) timescales. The observed X-ray emission in the NuSTAR energy range is fully consistent with the sum of the best-fit models of the spatially resolved Chandra spectra of the two nuclei.

  13. THERMAL MODEL CALIBRATION FOR MINOR PLANETS OBSERVED WITH WIDE-FIELD INFRARED SURVEY EXPLORER/NEOWISE

    SciTech Connect

    Mainzer, A.; Masiero, J.; Bauer, J.; Ressler, M.; Eisenhardt, P.; Grav, T.; Wright, E.; Cutri, R. M.; McMillan, R. S.; Cohen, M.

    2011-08-01

    With the Wide-field Infrared Survey Explorer (WISE), we have observed over 157,000 minor planets. Included in these are a number of near-Earth objects, main-belt asteroids, and irregular satellites which have well measured physical properties (via radar studies and in situ imaging) such as diameters. We have used these objects to validate models of thermal emission and reflected sunlight using the WISE measurements, as well as the color corrections derived in Wright et al. for the four WISE bandpasses as a function of effective temperature. We have used 50 objects with diameters measured by radar or in situ imaging to characterize the systematic errors implicit in using the WISE data with a faceted spherical near-Earth asteroid thermal model (NEATM) to compute diameters and albedos. By using the previously measured diameters and H magnitudes with a spherical NEATM model, we compute the predicted fluxes (after applying the color corrections given in Wright et al.) in each of the four WISE bands and compare them to the measured magnitudes. We find minimum systematic flux errors of 5%-10%, and hence minimum relative diameter and albedo errors of {approx}10% and {approx}20%, respectively. Additionally, visible albedos for the objects are computed and compared to the albedos at 3.4 {mu}m and 4.6 {mu}m, which contain a combination of reflected sunlight and thermal emission for most minor planets observed by WISE. Finally, we derive a linear relationship between subsolar temperature and effective temperature, which allows the color corrections given in Wright et al. to be used for minor planets by computing only subsolar temperature instead of a faceted thermophysical model. The thermal models derived in this paper are not intended to supplant previous measurements made using radar or spacecraft imaging; rather, we have used them to characterize the errors that should be expected when computing diameters and albedos of minor planets observed by WISE using a spherical

  14. Continuous uniformly finite time exact disturbance observer based control for fixed-time stabilization of nonlinear systems with mismatched disturbances

    PubMed Central

    Liu, Chongxin; Liu, Hang

    2017-01-01

    This paper presents a continuous composite control scheme to achieve fixed-time stabilization for nonlinear systems with mismatched disturbances. The composite controller is constructed in two steps: First, uniformly finite time exact disturbance observers are proposed to estimate and compensate the disturbances. Then, based on adding a power integrator technique and fixed-time stability theory, continuous fixed-time stable state feedback controller and Lyapunov functions are constructed to achieve global fixed-time system stabilization. The proposed control method extends the existing fixed-time stable control results to high order nonlinear systems with mismatched disturbances and achieves global fixed-time system stabilization. Besides, the proposed control scheme improves the disturbance rejection performance and achieves performance recovery of nominal system. Simulation results are provided to show the effectiveness, the superiority and the applicability of the proposed control scheme. PMID:28406966

  15. Cross-track Infrared Sounder (CrIS) satellite observations of tropospheric ammonia

    NASA Astrophysics Data System (ADS)

    Shephard, M. W.; Cady-Pereira, K. E.

    2015-03-01

    Observations of atmospheric ammonia are important in understanding and modelling the impact of ammonia on both human health and the natural environment. We present a detailed description of a robust retrieval algorithm that demonstrates the capabilities of utilizing Cross-track Infrared Sounder (CrIS) satellite observations to globally retrieval ammonia concentrations. Initial ammonia retrieval results using both simulated and real observations show that (i) CrIS is sensitive to ammonia in the boundary layer with peak vertical sensitivity typically around ~ 850-750 hPa (~ 1.5 to 2.5 km), which can dip down close to the surface (~ 900 hPa) under ideal conditions, (ii) it has a minimum detection limit of ~ 1 ppbv (peak profile value typically at the surface), and (iii) the information content can vary significantly with maximum values of ~ 1 degree-of-freedom for signal. Comparisons of the retrieval with simulated "true" profiles show a small positive retrieval bias of 6% with a standard deviation of ~ ± 20% (ranging from ± 12 to ± 30% over the vertical profile). Note that these uncertainty estimates are considered as lower bound values as no potential systematic errors are included in the simulations. The CrIS NH3 retrieval applied over the Central Valley in CA, USA, demonstrates that CrIS correlates well with the spatial variability of the boundary layer ammonia concentrations seen by the nearby Quantum Cascade-Laser (QCL) in situ surface and the Tropospheric Emission Spectrometer (TES) satellite observations as part of the DISCOVER-AQ campaign. The CrIS and TES ammonia observations show quantitatively similar retrieved boundary layer values that are often within the uncertainty of the two observations. Also demonstrated is CrIS's ability to capture the expected spatial distribution in the ammonia concentrations, from elevated values in the Central Valley from anthropogenic agriculture emissions, to much lower values in the unpolluted or clean surrounding

  16. Observation of finite-wavelength screening in high-energy-density matter

    PubMed Central

    Chapman, D. A.; Vorberger, J.; Fletcher, L. B.; Baggott, R. A.; Divol, L.; Döppner, T.; Falcone, R. W.; Glenzer, S. H.; Gregori, G.; Guymer, T. M.; Kritcher, A. L.; Landen, O. L.; Ma, T.; Pak, A. E.; Gericke, D. O.

    2015-01-01

    A key component for the description of charged particle systems is the screening of the Coulomb interaction between charge carriers. First investigated in the 1920s by Debye and Hückel for electrolytes, charge screening is important for determining the structural and transport properties of matter as diverse as astrophysical and laboratory plasmas, nuclear matter such as quark-gluon plasmas, electrons in solids, planetary cores and charged macromolecules. For systems with negligible dynamics, screening is still mostly described using a Debye–Hückel-type approach. Here, we report the novel observation of a significant departure from the Debye–Hückel-type model in high-energy-density matter by probing laser-driven, shock-compressed plastic with high-energy X-rays. We use spectrally resolved X-ray scattering in a geometry that enables direct investigation of the screening cloud, and demonstrate that the observed elastic scattering amplitude is only well described within a more general approach. PMID:25904218

  17. Observation of finite-wavelength screening in high-energy-density matter

    NASA Astrophysics Data System (ADS)

    Chapman, D. A.; Vorberger, J.; Fletcher, L. B.; Baggott, R. A.; Divol, L.; Döppner, T.; Falcone, R. W.; Glenzer, S. H.; Gregori, G.; Guymer, T. M.; Kritcher, A. L.; Landen, O. L.; Ma, T.; Pak, A. E.; Gericke, D. O.

    2015-04-01

    A key component for the description of charged particle systems is the screening of the Coulomb interaction between charge carriers. First investigated in the 1920s by Debye and Hückel for electrolytes, charge screening is important for determining the structural and transport properties of matter as diverse as astrophysical and laboratory plasmas, nuclear matter such as quark-gluon plasmas, electrons in solids, planetary cores and charged macromolecules. For systems with negligible dynamics, screening is still mostly described using a Debye-Hückel-type approach. Here, we report the novel observation of a significant departure from the Debye-Hückel-type model in high-energy-density matter by probing laser-driven, shock-compressed plastic with high-energy X-rays. We use spectrally resolved X-ray scattering in a geometry that enables direct investigation of the screening cloud, and demonstrate that the observed elastic scattering amplitude is only well described within a more general approach.

  18. Observation of finite-wavelength screening in high-energy-density matter

    DOE PAGES

    Chapman, D. A.; Vorberger, J.; Fletcher, L. B.; ...

    2015-04-23

    A key component for the description of charged particle systems is the screening of the Coulomb interaction between charge carriers. First investigated in the 1920s by Debye and Hückel for electrolytes, charge screening is important for determining the structural and transport properties of matter as diverse as astrophysical and laboratory plasmas, nuclear matter such as quark-gluon plasmas, electrons in solids, planetary cores and charged macromolecules. For systems with negligible dynamics, screening is still mostly described using a Debye–Hückel-type approach. Here, we report the novel observation of a significant departure from the Debye–Hückel-type model in high-energy-density matter by probing laser-driven, shock-compressedmore » plastic with high-energy X-rays. We use spectrally resolved X-ray scattering in a geometry that enables direct investigation of the screening cloud, and demonstrate that the observed elastic scattering amplitude is only well described within a more general approach.« less

  19. Observation of finite-wavelength screening in high-energy-density matter

    SciTech Connect

    Chapman, D. A.; Vorberger, J.; Fletcher, L. B.; Baggott, R. A.; Divol, L.; Döppner, T.; Falcone, R. W.; Glenzer, S. H.; Gregori, G.; Guymer, T. M.; Kritcher, A. L.; Landen, O. L.; Ma, T.; Pak, A. E.; Gericke, D. O.

    2015-04-23

    A key component for the description of charged particle systems is the screening of the Coulomb interaction between charge carriers. First investigated in the 1920s by Debye and Hückel for electrolytes, charge screening is important for determining the structural and transport properties of matter as diverse as astrophysical and laboratory plasmas, nuclear matter such as quark-gluon plasmas, electrons in solids, planetary cores and charged macromolecules. For systems with negligible dynamics, screening is still mostly described using a Debye–Hückel-type approach. Here, we report the novel observation of a significant departure from the Debye–Hückel-type model in high-energy-density matter by probing laser-driven, shock-compressed plastic with high-energy X-rays. We use spectrally resolved X-ray scattering in a geometry that enables direct investigation of the screening cloud, and demonstrate that the observed elastic scattering amplitude is only well described within a more general approach.

  20. Observation of finite-wavelength screening in high-energy-density matter.

    PubMed

    Chapman, D A; Vorberger, J; Fletcher, L B; Baggott, R A; Divol, L; Döppner, T; Falcone, R W; Glenzer, S H; Gregori, G; Guymer, T M; Kritcher, A L; Landen, O L; Ma, T; Pak, A E; Gericke, D O

    2015-04-23

    A key component for the description of charged particle systems is the screening of the Coulomb interaction between charge carriers. First investigated in the 1920s by Debye and Hückel for electrolytes, charge screening is important for determining the structural and transport properties of matter as diverse as astrophysical and laboratory plasmas, nuclear matter such as quark-gluon plasmas, electrons in solids, planetary cores and charged macromolecules. For systems with negligible dynamics, screening is still mostly described using a Debye-Hückel-type approach. Here, we report the novel observation of a significant departure from the Debye-Hückel-type model in high-energy-density matter by probing laser-driven, shock-compressed plastic with high-energy X-rays. We use spectrally resolved X-ray scattering in a geometry that enables direct investigation of the screening cloud, and demonstrate that the observed elastic scattering amplitude is only well described within a more general approach.

  1. Evolution of Titan's Lakes and Seas: Insights from Recent Infrared Observations

    NASA Astrophysics Data System (ADS)

    Sotin, C.; Seignovert, B.; Lawrence, K.; Barnes, J. W.; Brown, R. H.; Hayes, A.; Le Mouelic, S.; Baines, K. H.; Buratti, B. J.; Clark, R. N.; Nicholson, P. D.

    2013-12-01

    Titan's North Pole has been illuminated since the spring equinox in August 2009, allowing optical remote sensing instruments to acquire images of the lakes and seas that were discovered by the radar instrument earlier in the Cassini mission [1]. The illumination geometry continually improves with the incidence angle decreasing to its minimum at the summer solstice in 2017. Combined with highly inclined flybys that allow for small values of the emission angle, the 2013 observations are much less affected by the haze scattering because the optical path through the atmosphere is much shorter. The Visual and Infrared Mapping Spectrometer (VIMS) can observe Titan's surface in seven infrared atmospheric windows between 0.96- and 5-μm. This study describes observations acquired during the recent T93 flyby on July 26, 2013. The footprint ranges from 10 km/pixel to 3 km/pixel. Maps of the three large seas (Ligeia Mare, Punga Mare, and Kraken Mare) at seven different wavelengths are being constructed and a mosaic of the lake area is being assembled. Ligeia Mare was previously imaged by the VIMS in June 2010 [2]. A preliminary analysis of the 2-μm map suggests that the shoreline has not evolved since 2010. The shape of the 2- μm atmospheric window will be compared between the two images and between the mare and the shore to investigate whether liquid ethane is present as is the case on Ontario lacus [3]. The lake area located between 0 and 90W was imaged with a resolution that allows comparison with the radar images. A preliminary comparison between the two data sets shows a very strong correlation. One part of Punga mare and a lake known as Kivu lacus were acquired on the same image. The northeastern part of Punga Mare seems entailed by a river network. No connections between Punga mare and Kivu lacus are observed on the VIMS image. Kivu lacus seems to lie in the center of a circular depression whose limit is bright at 2-μm. Equipotential maps are built from the

  2. The Hyperspectral Infrared Imager (HyspIRI) and Global Observations of Tidal Wetlands

    NASA Astrophysics Data System (ADS)

    Turpie, K. R.; Klemas, V. V.; Byrd, K. B.; Kelly, M.; Jo, Y. H.

    2016-02-01

    HyspIRI mission will employ a high-spectral resolution VSWIR spectrometer, with a 30 m spatial resolution and swath width equal to Landsat legacy instruments. The spectrometer is expected to have a signal-to-noise (SNR) ratio comparable to or better than the Hyperspectral Imager of the Coastal Ocean (HICO). The mission will also provide an imaging radiometer with eight thermal bands at 60m resolution 600 km swath width. HyspIRI will offer new and unique opportunities to globally study ecosystems where land meets sea. In particular, the mission will be a boon to observations of tidal wetlands, which are highly productive and act as critical habitat for a wide variety of plants, fish, shellfish, and other wildlife. These ecotones between aquatic and terrestrial environments also provide protection from storm damage, run-off filtering, and recharge of aquifers. Many wetlands along coasts have been exposed to stress-inducing alterations globally, including dredge and fill operations, hydrologic modifications, pollutants, impoundments, fragmentation by roads/ditches, and sea level rise. For wetland protection and sensible coastal development, there is a need to monitor these ecosystems at global and regional scales. We will describe how the HyspIRI hyperspectral and thermal infrared sensors can be used to study and map key ecological properties of tidal salt and brackish marshes and mangroves, and perhaps other major wetland types, including freshwater marshes and wooded/shrub wetlands.

  3. Observations of the Infrared Solar Spectrum from Space by the ATMOS Experiment

    NASA Technical Reports Server (NTRS)

    Abrams, M. C.; Goldman, A.; Gunson, M. R.; Rinsland, C. P.; Zander, R.

    1999-01-01

    The final flight of the Atmospheric Trace Molecule Spectroscopy experiment as part of the Atmospheric na Laboratory for Applications and Science (ATLAS-3) Space Shuttle mission in 1994 provided a new opportunity to measure broadband 625-4800/ cm, 2.1 - 16 micron infrared solar spectra at an unapodized resolution of 0.0l/ cm from space. The majority of the observations were obtained as exoatmospheric, of near Sun center, absorption spectra, which were later ratioed to grazing atmospheric measurements to compute the atmospheric transmission of the Earth's atmosphere and analyzed for vertical profiles of minor and trace gases. Relative to the SPACELAB-3 mission that produced 4800 high Sun spectra (which were averaged into four grand average spectra), the ATLAS-3 mission produced some 40,000 high Sun spectra (which have been similarly averaged) with an improvement in signal-to-noise ratio of a factor of 3-4 in the spectral region between 1000 and 4800/ cm. A brief description of the spectral calibration and spectral quality is given as well as the location of electronic archives of these spectra.

  4. Stellar radial velocities using a laser frequency comb: Application and observations in the near infrared

    NASA Astrophysics Data System (ADS)

    Osterman, Steve

    2011-04-01

    The laser frequency comb presents the potential for a revolutionary increase in radial velocity precision by providing a calibration reference of unprecedented quality in terms of wavelength knowledge, repeatability, number, density, and regularity of lines. However, implementation has proven challenging, particularly in the near infrared. Nevertheless, with the right combination of comb and instrument, promising first steps have been taken, allowing for the derivation of stellar radial velocities in a wavelength range which is well suited to the observation of M dwarfs. These stars, with low mass and low luminosity, are the most prevalent class of stars within 10 parsecs and can be expected to yield a higher reflex velocity for a terrestrial mass planet in the liquid water habitable zone than would be the case with a more massive star such as our own. We present the design and both laboratory and on-sky performance of an H-band laser frequency comb used in conjunction with the Penn State Pathfinder testbed spectrograph and discuss lessons learned and plans for follow on testing with both the Pathfinder and the CSHELL instruments.

  5. 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.

  6. Infrared Spectroscopic Observations of the Secondary Stars of Short-period Sub-gap Cataclysmic Variables

    NASA Astrophysics Data System (ADS)

    Hamilton, Ryan T.; Harrison, Thomas E.; Tappert, Claus; Howell, Steve B.

    2011-02-01

    We present K-band spectroscopy of short-period, "sub-gap" cataclysmic variable (CV) systems obtained using ISAAC on the Very Large Telescope. We show the infrared (IR) spectra for nine systems below the 2-3 hr period gap: V2051 Oph, V436 Cen, EX Hya, VW Hyi, Z Cha, WX Hyi, V893 Sco, RZ Leo, and TY PsA. We are able to clearly detect the secondary star in all but WX Hyi, V893 Sco, and TY PsA. We present the first direct detection of the secondary stars of V2051 Oph, V436 Cen, and determine new spectral classifications for EX Hya, VW Hyi, Z Cha, and RZ Leo. We find that the CO band strengths of all but Z Cha appear normal for their spectral types, in contrast to their longer period cousins above the period gap. This brings the total number of CVs and pre-CVs with moderate resolution (R >~ 1500) IR spectroscopy to 61 systems: 19 pre-CVs, 31 non-magnetic systems, and 11 magnetic or partially magnetic systems. We discuss the trends seen in the IR abundance patterns thus far and highlight a potential link between anomalous abundances seen in the IR with the C IV/N V anomaly seen in the ultraviolet. We present a compilation of all systems with sufficient resolution IR observations to assess the CO band strengths and, by proxy, obtain an estimate on the C abundance on the secondary star.

  7. Experimental observation of infrared spectral enlargement in As2S3 suspended core microstructured fiber

    NASA Astrophysics Data System (ADS)

    El-Amraoui, M.; Fatome, J.; Jules, J. C.; Kibler, B.; Gadret, G.; Skripatchev, I.; Messadeq, Y.; Renversez, G.; Szpulak, M.; Troles, J.; Brilland, L.; Smektala, F.

    2010-04-01

    The development of chalcogenide glasses fibers for application in the infrared wavelength region between 1 and 10 μm is a big opportunity. More particularly, the possibility to generate efficient non linear effects above 2 μm is a real challenge. We present in this work the elaboration and optical characterizations of suspended core microstructured optical fibers elaborated from the As2S3 chalcogenide glass. As an alternative to the stack and draw process a mechanical machining has been used to the elaboration of the preforms. The drawing of these preforms into fibers allows reaching a suspended core geometry, in which a 2.5 μm diameter core is linked to the fiber clad region by three supporting struts. The zero dispersion wavelength is thus shifted towards 2 μm. At 1.55 μm our fibers exhibit a dispersion around -250 ps/nm/km. Their background level of losses is below 0,5 dB/m. By pumping them at 1.55 μm with a ps source, we observe self phase modulation as well as Raman generation. Finally a strong spectral enlargement is obtained with an average output power of - 5 dbm.

  8. Thermal infrared and visual observations of a water ice lag in the Mars southern summer

    USGS Publications Warehouse

    Titus, T.N.

    2005-01-01

    We present thermal infrared and visual evidence for the existence of water ice lags in the early southern summer. The observed H2O-ice lags lay in and near a chasma and appears to survive between 6-8 sols past the sublimation of the CO2. Possible sources of the H2O that compose the lag are (1) atmospheric H2O that is incorporated into the seasonal cap during condensation, (2) cold trapping of atmospheric water vapor onto the surface of the cap in the spring, or (3) a combination of the 2 processes where water is released from the sublimating cap only to be transported back over the cap edge and cold trapped. We refer to this later process as the "Houben" effect which may enrich the amount of water contained in the seasonal cap at 85??S by as much as a factor of 15. This phenomenon, which has already been identified for the northern retreating cap, may present an important water transport mechanism in the Southern Hemisphere.

  9. NEAR-INFRARED OBSERVATIONS OF GQ LUP b USING THE GEMINI INTEGRAL FIELD SPECTROGRAPH NIFS

    SciTech Connect

    Lavigne, Jean-Francois; Doyon, Rene; Lafreniere, David; Marois, Christian; Barman, Travis

    2009-10-20

    We present new JHK spectroscopy (R approx 5000) of GQ Lup b, acquired with the Near-Infrared Integral Field Spectrograph and the adaptive optics system ALTAIR at the Gemini North telescope. Angular differential imaging was used in the J and H bands to suppress the speckle noise from GQ Lup A; we show that this approach can provide improvements in signal-to-noise ratio (S/N) by a factor of 2-6 for companions located at subarcsecond separations. Based on high-quality observations and Global Astrometric lnterferometer for Astrophysics synthetic spectra, we estimate the companion effective temperature to T {sub eff} = 2400 +- 100 K, its gravity to log g = 4.0 +- 0.5, and its luminosity to log(L/L {sub sun}) = -2.47 +- 0.28. Comparisons with the predictions of the DUSTY evolutionary tracks allow us to constrain the mass of GQ Lup b to 8-60 M {sub Jup}, most likely in the brown dwarf regime. Compared with the spectra published by Seifahrt and collaborators, our spectra of GQ Lup b are significantly redder (by 15%-50%) and do not show important Pabeta emission. Our spectra are in excellent agreement with the lower S/N spectra previously published by McElwain and collaborators.

  10. Near-Infrared Observations of GQ Lup b Using the Gemini Integral Field Spectrograph NIFS

    NASA Astrophysics Data System (ADS)

    Lavigne, Jean-François; Doyon, René; Lafrenière, David; Marois, Christian; Barman, Travis

    2009-10-01

    We present new JHK spectroscopy (R ~ 5000) of GQ Lup b, acquired with the Near-Infrared Integral Field Spectrograph and the adaptive optics system ALTAIR at the Gemini North telescope. Angular differential imaging was used in the J and H bands to suppress the speckle noise from GQ Lup A; we show that this approach can provide improvements in signal-to-noise ratio (S/N) by a factor of 2-6 for companions located at subarcsecond separations. Based on high-quality observations and Global Astrometric lnterferometer for Astrophysics synthetic spectra, we estimate the companion effective temperature to T eff = 2400 ± 100 K, its gravity to log g = 4.0 ± 0.5, and its luminosity to log(L/L sun) = -2.47 ± 0.28. Comparisons with the predictions of the DUSTY evolutionary tracks allow us to constrain the mass of GQ Lup b to 8-60 M Jup, most likely in the brown dwarf regime. Compared with the spectra published by Seifahrt and collaborators, our spectra of GQ Lup b are significantly redder (by 15%-50%) and do not show important Paβ emission. Our spectra are in excellent agreement with the lower S/N spectra previously published by McElwain and collaborators.

  11. NEAR-INFRARED OBSERVATIONS OF COMET-LIKE ASTEROID (596) SCHEILA

    SciTech Connect

    Yang Bin; Hsieh, Henry E-mail: hsieh@ifa.hawaii.edu

    2011-08-20

    Asteroid (596) Scheila was reported to exhibit a cometary appearance and an increase in brightness on UT 2010 December 10.4. We used the IRCS spectrograph on the 8 m Subaru telescope to obtain medium-resolution spectra of Scheila in the HK band (1.4-2.5 {mu}m) and low-resolution spectra in the KL band (2.0-4.0 {mu}m) on UT 2010 December 13 and 14. In addition, we obtained low-resolution spectroscopy using the SpeX spectrograph on the 3 m NASA Infrared Telescope Facility on UT 2011 January 4 and 5. The spectrum of Scheila shows a consistent red slope from 0.8 to 4.0 {mu}m with no apparent absorption features, resembling spectra of D-type asteroids. An intimate mixing model suggests that the amount of water ice that might be present on the surface of Scheila is no more than a few percent. The spectrum of the Tagish Lake chondrite matches the asteroid's spectrum at shorter wavelengths ({lambda} < 2.5 {mu}m), but no hydration features are observed at longer wavelengths on Scheila. Our analysis corroborates other studies suggesting that the comet-like activity of Scheila is likely not caused by the sublimation of water ice. The dust coma and tail may be results of a recent impact event.

  12. COBE diffuse infrared background experiment observations of Galactic reddening and stellar populations

    NASA Technical Reports Server (NTRS)

    Arendt, R. G.; Berriman, G. B.; Boggess, N.; Dwek, E.; Hauser, M. G.; Kelsall, T.; Moseley, S. H.; Murdock, T. L.; Odegard, N.; Silverberg, R. F.

    1994-01-01

    This Letter describes the results of an initial study of Galactic extinction and the colors of Galactic stellar populations in the near-IR using the Diffuse Infrared Background Experiment (DIRBE) aboard the Cosmic Background Explorer (COBE) spacecraft. The near-IR reddening observed by DIRBE is consistent with the extinction law tabulated by Rieke & Lebofsky (1985). The distribution of dust and stars in most of the first and fourth quadrants of the Galactic plane (0 deg less than l less than 90 deg, and 270 deg less than l less than 360 deg, respectively) can be modeled as a stellar background source seen through up to approximately 4 mag of extinction at 1.25 micrometers. The unreddened near-IR colors of the Galactic disk are similar to those of late-K and M giants. The Galactic bulge exhibits slightly bluer colors in the 2.2-3.5 micrometers range, as noted by Terndrup et al. (1991). Star-forming regions exhibit colors that indicate the presence of a approximately 900 K continuum produced by hot dust or polycyclic aromatic hydrocarbons (PAHs) contributing at wavelengths as short as 3.5 micrometers.

  13. 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.

  14. 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.

  15. Development of a near-infrared balloon-borne camera for dayside and sunlit auroral observations

    NASA Astrophysics Data System (ADS)

    Zhou, X.-Y.; Lummerzheim, D.; Gladstone, R.; Rafol, S. B.; Gunapala, S.; He, Y.-T.; Hampton, D.

    2017-04-01

    Imaging aurora in daylight is a difficult and challenging task. The brightness of the sunlit atmosphere overwhelms the auroral emissions at visible wavelengths. Modeling of atmospheric brightness suggests that the contrast between auroral brightness and sky brightness makes it possible to image the aurora at near-infrared (NIR) wavelengths from sufficient altitudes. Preliminary experiments confirmed that the auroral N2+ Meinel emissions at about 1100 nm are bright enough to be extracted from atmospheric background brightness during daylight at about 40 km of a balloon altitude, which lead to the development of a high-performance NIR InGaAs camera that can be flown on a high-altitude and long-duration balloon. Auroral observations from such a platform are highly accommodated to current space missions (such as Time History of Events and Macroscale Interactions during Substorms/Acceleration Reconnection Turbulence and Electrodynamics of Moon's Interaction with the Sun, Magnetospheric Multiscale, Cluster, Geotail, and Defense Meteorological Satellite Program) and many ground-based measurements and will enhance the science return significantly.

  16. Far-infrared observations of a luminous dust-shrouded source in the nucleus of NGC 4945

    NASA Technical Reports Server (NTRS)

    Brock, David; Joy, Marshall; Lester, Daniel F.; Harvey, Paul M.; Ellis, H. Benton, Jr.

    1988-01-01

    High-resolution far-infrared observations of the galaxy NGC 4945 have been obtained from the Kuiper Airborne Observatory. Using new observational techniques and nonlinear deconvolution routines, it is found that virtually all of the far-infrared luminosity originates from a nuclear source no larger than 12 arcsec x 9 arcsec (225 pc x 170 pc) in extent. This size constraint, coupled with the far-infrared dust temperature, indicates that the source is deeply embedded in dust: the lower limit for the 100 micron optical depth is 0.35, which is by far the largest yet measured in an external galaxy. Published optical spectra of NGC 4945 reveal a heavily obscured nonthermal source which exhibits broad line profiles typical of a Seyfert 2 active nucleus; it is concluded that the far-infrared emission is probably due to thermal radiation from dust grains surrounding the nonthermal nuclear source. A compact cluster of massive young stars may also contribute to the infrared luminosity, but the evidence for such star-forming activity is weak.

  17. Joint US-Japan Observations with the Infrared Space Observatory (ISO): Deep Surveys and Observations of High-Z Objects

    NASA Technical Reports Server (NTRS)

    Sanders, David B.

    1997-01-01

    Several important milestones were passed during the past year of our ISO observing program: (1) Our first ISO data were successfully obtained. ISOCAM data were taken for our primary deep field target in the 'Lockman Hole'. Thirteen hours of integration (taken over 4 contiguous orbits) were obtained in the LW2 filter of a 3 ft x 3 ft region centered on the position of minimum HI column density in the Lockman Hole. The data were obtained in microscanning mode. This is the deepest integration attempted to date (by almost a factor of 4 in time) with ISOCAM. (2) The deep survey data obtained for the Lockman Hole were received by the Japanese P.I. (Yoshi Taniguchi) in early December, 1996 (following release of the improved pipeline formatted data from Vilspa), and a copy was forwarded to Hawaii shortly thereafter. These data were processed independently by the Japan and Hawaii groups during the latter part of December 1996, and early January, 1997. The Hawaii group made use of the U.S. ISO data center at IPAC/Caltech in Pasadena to carry out their data reduction, while the Japanese group used a copy of the ISOCAM data analysis package made available to them through an agreement with the head of the ISOCAM team, Catherine Cesarsky. (3) Results of our LW2 Deep Survey in the Lockman Hole were first reported at the ISO Workshop "Taking ISO to the Limits: Exploring the Faintest Sources in the Infrared" held at the ISO Science Operations Center in Villafranca, Spain (VILSPA) on 3-4 February, 1997. Yoshi Taniguchi gave an invited presentation summarizing the results of the U.S.-Japan team, and Dave Sanders gave an invited talk summarizing the results of the Workshop at the conclusion of the two day meeting. The text of the talks by Taniguchi and Sanders are included in the printed Workshop Proceedings, and are published in full on the Web. By several independent accounts, the U.S.-Japan Deep Survey results were one of the highlights of the Workshop; these data showed

  18. Observational studies on the near-infrared unidentified emission bands in galactic H II regions

    SciTech Connect

    Mori, Tamami I.; Onaka, Takashi; Sakon, Itsuki; Ohsawa, Ryou; Bell, Aaron C.; Ishihara, Daisuke; Shimonishi, Takashi

    2014-03-20

    Using a large collection of near-infrared spectra (2.5-5.4 μm) of Galactic H II regions and H II region-like objects, we perform a systematic investigation of astronomical polycyclic aromatic hydrocarbon (PAH) features. Thirty-six objects were observed using the infrared camera on board the AKARI satellite as a part of a director's time program. In addition to the well known 3.3-3.6 μm features, most spectra show a relatively weak emission feature at 5.22 μm with sufficient signal-to-noise ratios, which we identify as the PAH 5.25 μm band (previously reported). By careful analysis, we find good correlations between the 5.25 μm band and both the aromatic hydrocarbon feature at 3.3 μm and the aliphatic hydrocarbon features at around 3.4-3.6 μm. The present results give us convincing evidence that the astronomical 5.25 μm band is associated with C-H vibrations, as suggested by previous studies, and show its potential to probe the PAH size distribution. The analysis also shows that the aliphatic-to-aromatic ratio of I {sub 3.4-3.6} {sub μm}/I {sub 3.3} {sub μm} decreases against the ratio of the 3.7 μm continuum intensity to the 3.3 μm band, I {sub cont,} {sub 3.7} {sub μm}/I {sub 3.3} {sub μm}, which is an indicator of the ionization fraction of PAHs. The midinfrared color of I {sub 9} {sub μm}/I {sub 18} {sub μm} also declines steeply against the ratio of the hydrogen recombination line Brα at 4.05 μm to the 3.3 μm band, I {sub Brα}/I {sub 3.3} {sub μm}. These facts indicate possible dust processing inside or at the boundary of ionized gas.

  19. Variation in sunspot properties between 1999 and 2011 as observed with the Tenerife Infrared Polarimeter

    NASA Astrophysics Data System (ADS)

    Rezaei, R.; Beck, C.; Schmidt, W.

    2012-05-01

    Aims: We study the variation in the magnetic field strength and the umbral intensity of sunspots during the declining phase of the solar cycle No. 23 and in the beginning of cycle No. 24. Methods: We analyze a sample of 183 sunspots observed from 1999 until 2011 with the Tenerife Infrared Polarimeter (TIP) at the German Vacuum Tower Telescope (VTT). The magnetic field strength is derived from the Zeeman splitting of the Stokes-V signal in one near-infrared spectral line, either Fe i 1564.8 nm, Fe i 1089.6 nm, or Si i 1082.7 nm. This avoids the effects of the unpolarized stray light from the field-free quiet Sun surroundings that can affect the splitting seen in Stokes-I in the umbra. The minimum umbral continuum intensity and umbral area are also measured. Results: We find that there is a systematic trend for sunspots in the late stage of the solar cycle No. 23 to be weaker, i.e., to have a smaller maximum magnetic field strength than those at the start of the cycle. The decrease in the field strength with time of about 94 Gyr-1 is well beyond the statistical fluctuations that would be expected because of the larger number of sunspots close to cycle maximum (14 Gyr-1). In the same time interval, the continuum intensity of the umbra increases with a rate of 1.3 (±0.4)% of Ic yr-1, while the umbral area does not show any trend above the statistical variance. Sunspots in the new cycle No. 24 show higher field strengths and lower continuum intensities than those at the end of cycle No. 23, interrupting the trend. Conclusions: Sunspots have an intrinsically weaker field strength and brighter umbrae at the late stages of solar cycles compared to their initial stages, without any significant change in their area. The abrupt increase in field strength in sunspots of the new cycle suggests that the cyclic variations are dominating over any long-term trend that continues across cycles. We find a slight decrease in field strength and an increase in intensity as a long

  20. Observing Infrared Emission Lines of Neutron-Capture Species in Planetary Nebulae: New Detections with IGRINS

    NASA Astrophysics Data System (ADS)

    Dinerstein, Harriet L.; Sterling, N. C.; Kaplan, Kyle F.; Bautista, Manuel A.

    2015-08-01

    As the former envelopes of evolved stars, planetary nebulae (PNe) present an opportunity to study slow neutron-capture reactions (the “s-process”) during the AGB. Such studies differ from those of AGB stars in two ways. First, PNe represent the end point of self-enrichment and dredge-up in the star and most of its mass return to the ISM, enabling us to infer the nucleosynthetic yield of a specific element. Second, some s-process products are observable in PNe but difficult or impossible to observe in cool stars. These include some species with nuclear charge Z in the 30’s for which the major synthesis sites are uncertain. Optical emission lines of trans-iron species have been observed in some PNe, but are faint and can suffer from blending with lines of more abundant elements (Péquignot & Baluteau 1994, A&A, 283, 593; Sharpee et al. 2007, ApJ, 659, 1265). Observing infrared transitions from low energy states has proven to be a fruitful alternate approach. We used K-band lines of Se (Z=34) and Kr (Z=36) to study the demographics of their abundances in a large sample of Milky Way PNe (Dinerstein 2001, ApJ, 550, L223; Sterling & Dinerstein 2008, ApJ, 174, 158; Sterling, Porter, & Dinerstein 2015, submitted). An L-band emission line of Zn identified by Dinerstein & Geballe (2001, ApJ, 562, 515) and further observed by Smith, Zijlstra, & Dinerstein 2014 (MNRAS, 441, 3161), can be used as a tracer of the Fe-group, enabling determinations of the key stellar population diagnostic ratio [alpha/Fe] in PNe (see poster by Dinerstein et al., Focus Meeting 4). Using IGRINS, a high spectral resolution H and K band spectrometer (Park & Jaffe et al. 2014, Proc SPIE, 9147), we have discovered several new lines not previously reported in any astronomical object. Our detection of an H-band line of Rb (Z=37) confirms previous claims of optical Rb detections and indicates enrichment by a factor of ~4 in the PN NGC 7027 (Sterling, Dinerstein, Kaplan, & Bautista, in preparation

  1. Observation of the water cycle from space with the Atmospheric Infrared Sounder (AIRS)

    NASA Astrophysics Data System (ADS)

    Chahine, M. T.; Waliser, D. E.; Fetzer, E. J.; Olsen, E. T.

    2007-12-01

    AIRS is one of six instruments on board the Aqua satellite, part of NASA's Earth Observing System launched in a sun synchronous near polar orbit on May 4, 2002. AIRS and its partner microwave instrument, AMSU A, provide high quality data facilitating studies of the global water and energy cycles, climate variation and trends, and the response of the climate system to increased greenhouse gases. The exceptional stability of the AIRS instrument provides a climate record of thermal infrared radiance spectra spanning the 3.74 15.4 mm spectral band with 2378 channels at a nominal resolution of 1/1200. (Chahine et al, in BAMS, July 2006) Accurate knowledge of the vertical distribution of water vapor in the atmosphere is critically important to the determination of the warming the Earth will experience as a result of anthropogenic forcing. Comparison of the AIRS specific humidity product to state of the art climate models has shown most models exhibit a pattern of drier than observed (by 10 25%) in the tropics below 800 hPa and moister than observed (by 25 100%) between 300 and 600 hPa in the extra tropics (Pierce et al, GRL 2006). The AIRS water vapor measurements also reveal tropospheric moisture perturbations that are much larger than those depicted in previous NCAR/NCEP reanalysis and ECMWF analysis datasets, both of which have been widely used as observations to validate models. This suggests that the impact of convection induced downdrafts on the atmospheric boundary layer is significantly underestimated in both ECMWF and NCEP reanalysis (Fu et al., GRL 2006). AIRS data have led to the discovery of significant differences in the lower troposphere moisture and temperature fields during the spatial temporal evolution of the Madden Julian Oscillation (MJO). The anomalous lower troposphere temperature structure is observed in detail by AIRS for the Indian and western Pacific Oceans, while it remains much less well defined in the NCEP temperature fields (Tian et al

  2. Near-infrared colors of asteroid 2012 DA14 at its closest approach to Earth: Observations with the Nishiharima Infrared Camera (NIC)

    NASA Astrophysics Data System (ADS)

    Takahashi, Jun; Urakawa, Seitaro; Terai, Tsuyoshi; Hanayama, Hidekazu; Arai, Akira; Honda, Satoshi; Takagi, Yuhei; Itoh, Yoichi; Zenno, Takahiro; Ishiguro, Masateru

    2014-06-01

    We present the results of our JHKs photometry of asteroid 2012 DA14 at its closest approach to Earth on 2013 February 15. Possible spectral changes associated with resurfacing by planetary encounters are of great interest. The Earth flyby of 2012 DA14 provided a rare opportunity to investigate this effect. Our observations were conducted using the Nishiharima Infrared Camera (NIC) attached to the 2.0 m Nayuta telescope at the Nishi-Harima Astronomical Observatory. Despite the extraordinarily fast sky motion of up to near 50″ s-1, the telescope successfully tracked the asteroid. The NIC achievement of three-band simultaneous observations allowed us to reliably deduce the colors of this fast-moving object. The derived near-infrared relative reflectances are flat, which is consistent with the classification of the asteroid as L-type. The J - H and H - Ks colors at 0.5-1 hr after the closest approach are compared with those observed by de León (2013, A&A, 555, L2) at ˜ 10 hr after the closest time. We did not detect color changes significantly exceeding the photometric errors, which are ˜ 0.1 mag. This project has demonstrated the potential of the NIC as a three-band simultaneous imager, especially for observations of rapidly time-variable phenomena.

  3. Relationship between ice water path and downward longwave radiation for clouds optically thin in the infrared: Observations and model calculations

    NASA Technical Reports Server (NTRS)

    Uttal, Taneil; Matrosov, Sergey Y.; Snider, Jack B.; Kropfli, Robert A.

    1994-01-01

    A vertically pointing 3.2-cm radar is used to observe altostratus and cirrus clouds as they pass overhead. Radar reflectivities are used in combination with an empirical Z(sub i)-IWC (ice water content) relationship developed by Sassen (1987) to parameterize IWC, which is then integrated to obtain estimates of ice water path (IWP). The observed dataset is segregated into all-ice and mixed-phase periods using measurements of integrated liquid water paths (LWP) detected by a collocated, dual-channel microwave radiometer. The IWP values for the all ice periods are compared to measurements of infrared (IR) downward fluxes measured by a collocated narrowband (9.95-11.43 microns) IR radiometer, which results in scattergrams representing the observed dependence of IR fluxes on IWP. A two-stream model is used to calculate the infrared fluxes expected from ice clouds with boundary conditions specified by the actual clouds, and similar curves relating IWP and infrared fluxes are obtained. The model and observational results suggest that IWP is one of the primary controls on infrared thermal fluxes for ice clouds.

  4. The dusty AGB star RS CrB: first mid-infrared interferometric observations with the Keck telescopes

    NASA Technical Reports Server (NTRS)

    Mennesson, B.; Koresko, C.; Creech-Eakman, M. J.; Serabyn, E.; Colavita, M. M; Akeson, R.; Appleby, E.; Bell, J.; Booth, A.; Crawford, S.; Dahl, W.; Fanson, J.; Felizardo, C.; Garcia, J.; Gathright, J.; Herstein, J.; Hovland, E.; Hrynevych, M.; Johansson, E.; Le Mignant, D.; Ligon, R.; Millan-Gabet, R.; Moore, J.; Neyman, C.; Palmer, D.

    2005-01-01

    We report interferometric observations of the semiregular variable star RS CrB, a red giant with strong silicate emission features. The data were among the first long-baseline mid-infrared stellar fringes obtained between the Keck telescopes, using parts of the new nulling beam combiner.

  5. The life cycles of Be viscous decretion discs: time-dependent modelling of infrared continuum observations

    NASA Astrophysics Data System (ADS)

    Vieira, R. G.; Carciofi, A. C.; Bjorkman, J. E.; Rivinius, Th.; Baade, D.; Rímulo, L. R.

    2017-01-01

    We apply the viscous decretion disc (VDD) model to interpret the infrared disc continuum emission of 80 Be stars observed in different epochs. In this way, we determined 169 specific disc structures, namely their density scale, ρ0, and exponent, n. We found that the n values range mainly between 1.5 and 3.5, and ρ0 varies between 10-12 and 10-10 g cm-3, with a peak close to the lower value. Our large sample also allowed us to firmly establish that the discs around early-type stars are denser than in late-type stars. Additionally, we estimated the disc mass decretion rates and found that they range between 10-12 and 10-9 M⊙ yr-1. These values are compatible with recent stellar evolution models of fast-rotating stars. One of the main findings of this work is a correlation between the ρ0 and n values. In order to find out whether these relations can be traced back to the evolution of discs or have some other origin, we used the VDD model to calculate temporal sequences under different assumptions for the time profile of the disc mass injection. The results support the hypothesis that the observed distribution of disc properties is due to a common evolutionary path. In particular, our results suggest that the time-scale for disc growth, during which the disc is being actively fed by mass injection episodes, is shorter than the time-scale for disc dissipation, when the disc is no longer fed by the star and dissipates as a result of the viscous diffusion of the disc material.

  6. Global Infrared Observations of Roughness Induced Transition on the Space Shuttle Orbiter

    NASA Technical Reports Server (NTRS)

    Horvath, Thomas J.; Zalameda, Joseph N.; Wood, William A.; Berry, Scott A.; Schwartz, Richard J.; Dantowitz, Ronald F.; Spisz, Thomas S.; Taylor, Jeff C.

    2012-01-01

    High resolution infrared observations made from a mobile ground based optical system captured the laminar-to-turbulent boundary layer transition process as it occurred during Space Shuttle Endeavour's return to earth following its final mission in 2011. The STS-134 imagery was part of a larger effort to demonstrate an emerging and reliable non-intrusive global thermal measurement capability and to complement a series of boundary layer transition flight experiments that were flown on the Shuttle. The STS-134 observations are believed to be the first time that the development and movement of a hypersonic boundary layer transition front has been witnessed in flight over the entire vehicle surface and in particular, at unprecedented spatial resolution. Additionally, benchmark surface temperature maps of the Orbiter lower surface collected over multiple flights and spanning a Mach range of 18 to 6 are now available and represent an opportunity for collaborative comparison with computational techniques focused on hypersonic transition and turbulence modeling. The synergy of the global temperature maps with the companion in-situ thermocouple measurements serve as an example of the effective leveraging of resources to achieve a common goal of advancing our understanding of the complex nature of high Mach number transition. It is shown that quantitative imaging can open the door to a multitude of national and international opportunities for partnership associated with flight-testing and subsequent validation of numerical simulation techniques. The quantitative imaging applications highlighted in this paper offer unique and complementary flight measurement alternatives and suggest collaborative instrumentation opportunities to advance the state of the art in transition prediction and maximize the return on investment in terms of developmental flight tests for future vehicle designs.

  7. Project 1640 Observations of Brown Dwarf GJ 758 B: Near-infrared Spectrum and Atmospheric Modeling

    NASA Astrophysics Data System (ADS)

    Nilsson, R.; Veicht, A.; Giorla Godfrey, P. A.; Rice, E. L.; Aguilar, J.; Pueyo, L.; Roberts, L. C., Jr.; Oppenheimer, R.; Brenner, D.; Luszcz-Cook, S. H.; Bacchus, E.; Beichman, C.; Burruss, R.; Cady, E.; Dekany, R.; Fergus, R.; Hillenbrand, L.; Hinkley, S.; King, D.; Lockhart, T.; Parry, I. R.; Sivaramakrishnan, A.; Soummer, R.; Vasisht, G.; Zhai, C.; Zimmerman, N. T.

    2017-03-01

    The nearby Sun-like star GJ 758 hosts a cold substellar companion, GJ 758 B, at a projected separation of ≲30 au, previously detected in high-contrast multi-band photometric observations. In order to better constrain the companion’s physical characteristics, we acquired the first low-resolution (R ˜ 50) near-infrared spectrum of it using the high-contrast hyperspectral imaging instrument Project 1640 on Palomar Observatory’s 5 m Hale telescope. We obtained simultaneous images in 32 wavelength channels covering the Y, J, and H bands (˜952-1770 nm), and used data processing techniques based on principal component analysis to efficiently subtract chromatic background speckle-noise. GJ 758 B was detected in four epochs during 2013 and 2014. Basic astrometric measurements confirm its apparent northwest trajectory relative to the primary star, with no clear signs of orbital curvature. Spectra of SpeX/IRTF observed T dwarfs were compared to the combined spectrum of GJ 758 B, with χ 2 minimization suggesting a best fit for spectral type T7.0 ± 1.0, but with a shallow minimum over T5-T8. Fitting of synthetic spectra from the BT-Settl13 model atmospheres gives an effective temperature T eff = 741 ± 25 K and surface gravity {log}g=4.3+/- 0.5 dex (cgs). Our derived best-fit spectral type and effective temperature from modeling of the low-resolution spectrum suggest a slightly earlier and hotter companion than previous findings from photometric data, but do not rule out current results, and confirm GJ 758 B as one of the coolest sub-stellar companions to a Sun-like star to date.

  8. Near-Infrared Photon-Counting Camera for High-Sensitivity Observations

    NASA Technical Reports Server (NTRS)

    Jurkovic, Michael

    2012-01-01

    The dark current of a transferred-electron photocathode with an InGaAs absorber, responsive over the 0.9-to-1.7- micron range, must be reduced to an ultralow level suitable for low signal spectral astrophysical measurements by lowering the temperature of the sensor incorporating the cathode. However, photocathode quantum efficiency (QE) is known to reduce to zero at such low temperatures. Moreover, it has not been demonstrated that the target dark current can be reached at any temperature using existing photocathodes. Changes in the transferred-electron photocathode epistructure (with an In- GaAs absorber lattice-matched to InP and exhibiting responsivity over the 0.9- to-1.7- m range) and fabrication processes were developed and implemented that resulted in a demonstrated >13x reduction in dark current at -40 C while retaining >95% of the approximately equal to 25% saturated room-temperature QE. Further testing at lower temperature is needed to confirm a >25 C predicted reduction in cooling required to achieve an ultralow dark-current target suitable for faint spectral astronomical observations that are not otherwise possible. This reduction in dark current makes it possible to increase the integration time of the imaging sensor, thus enabling a much higher near-infrared (NIR) sensitivity than is possible with current technology. As a result, extremely faint phenomena and NIR signals emitted from distant celestial objects can be now observed and imaged (such as the dynamics of redshifting galaxies, and spectral measurements on extra-solar planets in search of water and bio-markers) that were not previously possible. In addition, the enhanced NIR sensitivity also directly benefits other NIR imaging applications, including drug and bomb detection, stand-off detectio