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. Catalog of infrared observations

    NASA Astrophysics Data System (ADS)

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

    1984-05-01

    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.

  3. 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.

  4. 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.

  5. 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.

  6. Infrared observations of the planets

    NASA Technical Reports Server (NTRS)

    Low, F. J.

    1974-01-01

    The planetary observations presented are divided into three parts: (1) infrared photometry at all wavelengths accessible from the ground; (2) high resolution infrared mapping of Jupiter with special emphasis at 5 microns; and (3) extensive infrared observations of Comet Kohoutek. Results are briefly summarized.

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

    NASA Astrophysics Data System (ADS)

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

    1988-08-01

    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.

  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. 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.

  11. Evidence for infrared-finite coupling in Sudakov resummation

    SciTech Connect

    Grunberg, Georges

    2006-05-01

    New arguments are presented in favor of the infrared-finite coupling approach to power corrections in the context of Sudakov resummation. The more regular infrared behavior of some peculiar combinations of Sudakov anomalous dimensions, free of Landau singularities at large N{sub f}, is pointed out. A general conflict between the infrared-finite coupling and infrared renormalon approaches to power corrections is explained, and a possible resolution is proposed, which makes use of the arbitrariness of the choice of constant terms in the Sudakov exponent. Evidence for an infrared-finite perturbative effective coupling in the Drell-Yan process at large N{sub f} (albeit at odds with the infrared renormalon argument) is found within the framework of Sudakov resummation for eikonal cross sections of Laenen, Sterman and Vogelsang.

  12. 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.

  13. Infrared astronomical data base and catalog of infrared observations

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    The NASA/Goddard Space Flight Center has developed a computer data base of infrared astronomical observations. The data base represents a machine-readable library of infrared observational data published in the relevant literature since 1960 for celestial sources outside the solar system. It likewise includes the contents of infrared surveys and catalogs. A catalog of infrared observations has been developed in both printed and magnetic-tape formats. The data base will be accessed through a bibliographic guide and an atlas of infrared source names and positions. Future plans also include two-dimensional graphical displays of infrared data and a user-interactive data terminal.

  14. 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.

  15. Infrared astronomical data base and catalog of infrared observations

    NASA Astrophysics Data System (ADS)

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

    A computer data base of infrared astronomical observations has been established at NASA/Goddard Space Flight Center. It contains a summary of all infrared (1-100 microns) observations of celestial sources outside the solar system, published in the major scientific journals since 1960, as well as the contents of infrared surveys and catalogs. A Catalog of Infrared Observations (CIO) has been developed from the data base in printed and magnetic tape versions. A bibliographic Guide to the Infrared Astronomical Literature, and an Altas of Infrared Source Names and Positions will be published in conjunction with the catalog. Future plans include development of an interactive data system at Goddard which will give a user direct access to the computerized data.

  16. Infrared astronomical data base and catalog of infrared observations

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    A computer data base of infrared astronomical observations has been established at NASA/Goddard Space Flight Center. It contains a summary of all infrared (1-100 microns) observations of celestial sources outside the solar system, published in the major scientific journals since 1960, as well as the contents of infrared surveys and catalogs. A Catalog of Infrared Observations (CIO) has been developed from the data base in printed and magnetic tape versions. A bibliographic Guide to the Infrared Astronomical Literature, and an Altas of Infrared Source Names and Positions will be published in conjunction with the catalog. Future plans include development of an interactive data system at Goddard which will give a user direct access to the computerized data.

  17. Scattering matrix of infrared radiation by ice finite circular cylinders.

    PubMed

    Xu, Lisheng; Ding, Jilie; Cheng, Andrew Y S

    2002-04-20

    Scattering matrix characteristics of polydisperse, randomly oriented, small ice crystals modeled by finite circular cylinders with various ratios of the length to diameter (L/D) ratio are calculated by use of the exact T-matrix approach, with emphasis on the thermal infrared spectral region that extends from the atmospheric short-wave IR window to the far-IR wavelengths to as large as 30 microm. The observed ice crystal size distribution and the well-known power-law distribution are considered. The results of the extensive calculations show that the characteristics of scattering matrix elements of small ice circular cylinders depend strongly on wavelengths and refractive indices, particle size distributions, and the L/D ratios. The applicability of the power-law distribution and particle shapes for light scattering calculations for small ice crystals is discussed. The effects of the effective variance of size distribution on light scattering characteristics are addressed. It seems from the behavior of scattering matrix elements of small ice crystals that the combination of 25 and 3.979 microm has some advantages and potential applications for remote sensing of cirrus and other ice clouds.

  18. 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.

  19. 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.

  20. Catalog of infrared observations. Part 2: Appendixes

    NASA Astrophysics Data System (ADS)

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

    1987-12-01

    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.

  1. 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.

  2. 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.

  3. 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.

  4. Infrared observations of southern RV Tauri stars.

    NASA Technical Reports Server (NTRS)

    Gehrz, R. D.; Ney, E. P.

    1972-01-01

    Photometric measurements from 2.2 to 18 microns are reported for six southern RV Tauri stars. Four of the six have anomalous infrared excess radiation similar to that observed in other RV Tauri stars. The infrared spectra of IW Car, AR Pup, and SX Cen resemble that of oxygen-rich RV Tau. RU Cen is similar to AC Her.

  5. 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.

  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. Catalog of infrared observations. Part 1: Data

    NASA Astrophysics Data System (ADS)

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

    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.

  9. 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.

  10. Infrared observations of RS CVn stars

    NASA Technical Reports Server (NTRS)

    Berriman, G.; De Campli, W. M.; Werner, M. W.; Hatchett, S. P.

    1983-01-01

    The paper presents infrared photometry of the RS CVn binary stars AR Lac (1.2-10 microns) and MM Her (1.2-3.5 microns) as they egressed from their primary and secondary eclipses; of the eclipsing systems RS CVn and Z Her at maximum light (1.2-10 microns) and of the non-eclipsing systems UX Ari and HR 1099 (1.2-10 microns). An analysis of these and published V data based on flux ratio diagrams (linear analogues of color-color diagrams) shows that G and K stars supply the infrared light of these systems. In AR Lac, the combined light of a G5-K0 subgiant and either a late F dwarf or an early F subgiant can account for the observed visual and infrared light curves. None of these systems shows infrared emission from circumstellar matter. This result is simply understood: dust grains would not be expected to form in the physical conditions surrounding the subgiant, and the corona and chromosphere (whose properties have been deduced from spectroscopic X-ray observations) should not produce appreciable infrared emission.

  11. 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.

  12. 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.

  13. 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

  14. Longwave infrared observation of urban landscapes

    NASA Technical Reports Server (NTRS)

    Goward, S. N.

    1981-01-01

    An investigation is conducted regarding the feasibility to develop improved methods for the identification and analysis of urban landscapes on the basis of a utilization of longwave infrared observations. Attention is given to landscape thermal behavior, urban thermal properties, modeled thermal behavior of pavements and buildings, and observed urban landscape thermal emissions. The differential thermal behavior of buildings, pavements, and natural areas within urban landscapes is found to suggest that integrated multispectral solar radiant reflectance and terrestrial radiant emissions data will significantly increase potentials for analyzing urban landscapes. In particular, daytime satellite observations of the considered type should permit better identification of urban areas and an analysis of the density of buildings and pavements within urban areas. This capability should enhance the utility of satellite remote sensor data in urban applications.

  15. 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.

  16. 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. PMID:24664918

  17. 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.

  18. 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.

  19. Observations of Circumstellar Disks with Infrared Interferometry

    NASA Technical Reports Server (NTRS)

    Akeson, Rachel

    2008-01-01

    Star formation is arguably the area of astrophysics in which infrared interferometry has had the biggest impact. The optically thick portion of T Tauri and Herbig Ae/Be disks DO NOT extend to a few stellar radii of the stellar surface. Emission is coming from near the dust sublimation radius, but not all from a single radius. The Herbig Ae stars can be either flared or self-shadowed but very massive (early Be) stars are geometrically thin. The Herbig Ae stars can be either flared or self-shadowed but very massive (early Be) stars are geometrically thin. Observational prospects are rapidly improving: a) Higher spectral resolution will allow observations of the gas: jets, winds, accretion. b) Closure phase and imaging will help eliminate model uncertainties/dependencies.

  20. Infrared lidar observations of stratospheric aerosols.

    PubMed

    Forrister, H N; Roberts, D W; Mercer, A J; Gimmestad, G G

    2014-06-01

    We observed the stratospheric aerosol layer at 34° north latitude with a photon-counting 1574 nm lidar on three occasions in 2011. During all of the observations, we also operated a nearby 523.5 nm micropulse lidar and acquired National Weather Service upper air data. We analyzed the lidar data to find scattering ratio profiles and the integrated aerosol backscatter at both wavelengths and then calculated the color ratio and wavelength exponent for lidar backscattering from the stratospheric aerosols. The visible-light integrated backscatter values of the layer were in the range 2.8-3.5×10⁻⁴ sr⁻¹ and the infrared integrated backscatter values ranged from 2.4 to 3.7×10⁻⁵  sr⁻¹. The wavelength exponent was determined to be 1.9±0.2.

  1. 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.

  2. 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

  3. SCUBA Observations of MSX Infrared Dark Clouds

    NASA Astrophysics Data System (ADS)

    Carey, S. J.; Redman, R. O.; Feldman, P. A.; Egan, M. P.; Shipman, R. F.

    1999-01-01

    We present 850 and 450 μ m continuum images of 9 infrared dark clouds (IRDCs; Egan et al. 1998, ApJ, 494, L199) taken with the Submillimeter Common-User Bolometer Array (SCUBA) on the JCMT. The IRDCs appear to be very large (1-10 pc diameter) molecular cores with gas densities > 106 cm-3 and temperatures around 10 K. Approximately 5000 IRDCs have been identified in a survey of the inner Galactic Plane with the distribution of IRDCs peaking at the longitudes of spiral arm tangent points and the molecular ring. All nine clouds were detected as strong submillimeter sources with peak flux densities of 1 Jy/beam at 850 μ m. In general, the submillimeter emission follows the mid-infrared extinction and H2CO rotational line emission morphologies (Carey et al. 1998, ApJ, 508, 721). The submillimeter data reveals substructure in the IRDCs including bright 850 μ m knots. The observed H2CO line profiles are non-Gaussian suggesting the presence of molecular outflows in some of the IRDCs. It is likely that the 850 μ m emission peaks are either Class 0 protostars or pre-protostellar objects. Estimates of the dust mass and temperature will be compared to previous estimates of gas mass and temperature for IRDCs.

  4. 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.

  5. 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.

  6. 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.

  7. Robust finite time observer design for multicellular converters

    NASA Astrophysics Data System (ADS)

    Defoort, Michael; Djemai, Mohamed; Floquet, Thierry; Perruquetti, Wilfrid

    2011-11-01

    In this article, a nonlinear finite time observer is designed for multicellular converters. The aim is to estimate the capacitor voltages by taking into account the hybrid behaviour of the converter. This article extends the validity of the strong Lyapunov function, proposed in Moreno and Osorio (Moreno, J., and Osorio, M. (2008), 'A Lyapunov Approach to Second Order Sliding Mode Controllers and Observers', in Proceedings of the IEEE Conference on Decision and Control, New Orleans, USA, pp. 2856-2861), in order to deeply study the reaching time estimation and robustness of the homogeneous finite time observer given in Perruquetti et al. (Perruquetti, W., Floquet, T., and Moulay, E. (2008), 'Finite Time Observers: Application to Secure Communication', IEEE Transactions on Automatic Control, 53, 356-360). The proposed approach enables the stabilisation of the observation errors in spite of the presence of perturbations and uncertainties. Some simulations and comparisons with the super-twisting sliding mode observer highlight the efficiency of the proposed strategy.

  8. 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.

  9. 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…

  10. Easy observation of infrared spectral lines

    NASA Astrophysics Data System (ADS)

    Cortel, Adolf

    2012-05-01

    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 flame of a Bunsen burner.

  11. Catalog of Infrared Observations. Part I: Data. Part II: Appendixes.

    NASA Astrophysics Data System (ADS)

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

    The Catalog of Infrared Observations (CIO) is a compilation of infrared astronomical data obtained from an extensive literature search of astronomical journals and major astronomical catalogs and surveys. The literature searches are complete for years 1965 through 1986. 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 an atlas of infrared spectral ranges, and IRAS data for the CIO sources. The complete CIO database is available in printed microfiche and magnetic tape formats.

  12. Infrared observations of galactic bulge X-ray sources

    NASA Technical Reports Server (NTRS)

    Hertz, P.; Grindlay, J. E.

    1984-01-01

    Nine unidentified galactic bulge X-ray sources, the recently identified X-ray burster MXB 1728-34, and two optically identified sources (Sco X-1 and MXB 1735-44) were observed with the NASA 3 m Infrared Telescope Facility. The data constrain both the presence of diffuse infrared sources near the X-ray positions and the flux of possible infrared counterparts. None of the nine unidentified sources lies within obscured globular clusters, although there is marginal evidence for diffuse infrared emission near 4U 1822-00 and 4U 1916-05. This implies that at most two additional luminous galactic bulge X-ray sources lie within undiscovered, obscured globular clusters. No infrared counterparts were detected for unidentified sources; the limits derived are consistent with all of the sources observed being similar to the low mass X-ray binary Sco X-1.

  13. 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

  14. Infrared observations of P/Halley and P/Encke

    NASA Technical Reports Server (NTRS)

    Gehrz, Robert D.; Ney, E. P.

    1988-01-01

    Broadband optical/infrared photometers responding from 0.5 to 23 microns mounted on the Univ. of Minnesota (UM) O'Brien 76-cm telescope, Wyoming Infrared Observatory 234-cm telescope, and UM's Mount Lemmon Infrared Observatory 152-cm telescope were used to measure comet Halley more than 30 times between 12 Dec. 1985 to 6 May 1986. The Wyoming system was used to measure P/Encke on 24 Jul. 1987. The equipment and observations of Halley were fully described by Gehrz and Ney. Conclusions based on a preliminary analysis of the Halley and P/Encke data are reported.

  15. NGC 2024: Far-infrared and radio molecular observations

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    Far infrared continuum and millimeter wave molecular observations are presented for the infrared and radio source NGC 2024. The measurements are obtained at relatively high angular resolution, enabling a description of the source energetics and mass distribution in greater detail than previously reported. The object appears to be dominated by a dense ridge of material, extended in the north/south direction and centered on the dark lane that is seen in visual photographs. Maps of the source using the high density molecules CS and HCN confirm this picture and allow a description of the core structure and molecular abundances. The radio molecular and infrared observations support the idea that an important exciting star in NGC 2024 has yet to be identified and is centered on the dense ridge about 1' south of the bright mid infrared source IRS 2. The data presented here allows a presentation of a model for the source.

  16. 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.

  17. Observation of infrared emission spectra from silicon combustion products

    NASA Astrophysics Data System (ADS)

    Smit, Kenneth J.; De Yong, Leo V.; Gray, Rodney

    1996-05-01

    The combustion of silicon based pyrotechnic compositions is observed with time resolved infrared spectrometry. This revealed the build up of strong emission at 9.1 ± 0.1 μm, which is associated with condensed silicon dioxide particulates. Time averaged spectra for compositions containing different oxidants or binders illustrate the dependence of SiO 2 emission intensity on composition.

  18. Carbon Monoxide Retrievals From Short Wave Infrared Observations Of Sciamachy

    NASA Astrophysics Data System (ADS)

    Schreier, Franz; Gimeno-Garcia, Sebastian; Lihtenberg, Gunter; Hess, Michael

    2013-12-01

    For the estimation of vertical column densities from short-wave near infrared nadir observations from SCIA- MACHY (and similar instruments like GOSAT) the “Beer InfraRed Retrieval Algorithm” BIRRA has been developed that performs a nonlinear or separable least squares fit of concentration profile scaling factors along with some auxiliary parameters. Our recent work focuses on improvements with respect to wavelength calibration, a more flexible multiwindow fitting scheme, and a better modeling of SCIAMACHY's channel 8 spectral response function. Here we present results from carbon monoxide retrevials from SCIAMACHY's channel 8 indicating the significant impact of fitting the wavelength shift.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Thermal-infrared spectral observations of geologic materials in emission

    NASA Technical Reports Server (NTRS)

    Christensen, Philip R.; Luth, Sharon J.

    1987-01-01

    The thermal-infrared spectra of geologic materials in emission were studied using the prototype Thermal Emission Spectrometer (TES). A variety of of processes and surface modifications that may influence or alter the spectra of primary rock materials were studied. It was confirmed that thermal emission spectra contain the same absorption features as those observed in transmission and reflection spectra. It was confirmed that the TES instrument can be used to obtain relevant spectra for analysis of rock and mineral composition.

  4. 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%.

  5. 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

  6. 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.

  7. Sensitive observations with the Spacelab 2 infrared telescope

    NASA Astrophysics Data System (ADS)

    Young, E. T.; Rieke, G. H.; Gautier, T. N.; Hoffmann, W. F.; Low, F. J.; Poteet, W.; Fazio, G. G.; Koch, D.; Traub, W. A.; Urban, E. W.

    The small helium-cooled infrared telescope (Spacelab IRT) is a multiband instrument capable of highly sensitive observations from space. The experiment consists of a cryogenically cooled, very well baffled telescope with a ten channel focal plane array. During the Spacelab 2 flight of the Space Shuttle, this instrument will make observations between 5 and 120 micron wavelength that will be background limited by the expected zodiacal emission. Design considerations necessitated by this level of performance are discussed in this paper. In particular, the operation of a very sensitive focal plane array in the space environment is described. The Spacelab IRT will be used to map the extended, low-surface brightness celestial emission. During the seven day length of the mission better than 70 percent sky coverage is expected. The instrument will also be used to measure the infrared contamination environment of the Space Shuttle. This information will be important in the development of the next generation of infrared astronomical instruments. The performance of the Spacelab IRT, in particular its sensitivity to the contamination environment is detailed.

  8. Infrared observations of the saturnian system from voyager 1.

    PubMed

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

    1981-04-10

    During the passage of Voyager 1 through the Saturn system, the infrared instrument acquired spectral and radiometric data on Saturn, the rings, and Titan and other satellites. Infrared spectra of Saturn indicate the presence of H(2), CH(4), NH(3), PH(3), C(2)H(2), C(2)H(6), and possibly C(3)H(4) and C(3)H(8). A hydrogen mole fraction of 0.94 is inferred with an uncertainty of a few percent, implying a depletion of helium in the atmosphere of Saturn relative to that of Jupiter. The atmospheric thermal structure of Saturn shows hemisphere asymmetries that are consistent with a response to the seasonally varying insolation. Extensive small-scale latitudinal structure is also observed. On Titan, positive identifications of infrared spectral features are made for CH(4), C(2)H(2), C(2)H(4), C(2)H(6), and HCN; tentative identifications are made for C(3)H(4) and C(3)H(8). The infrared continuum opacity on Titan appears to be quite small between 500 and 600 cm(-1), implying that the solid surface is a major contributor to the observed emission over this spectral range; between 500 and 200 cm(-1) theopacity increases with decreasing wave number, attaining an optical thickness in excess of 2 at 200 cm(-1). Temperatures near the 1-millibar level are independent of longitude and local time but show a decrease of approximately 20 K between the equator and north pole, which suggests a seasonally dependent cyclostrophic zonal flow in the stratosphere of approximately 100 meters per second. Measurements of the C ring of Saturn yield a temperature of 85 +/- 1 K and an infrared optical depth of 0.09 +/- 0.01. Radiometer observations of sunlight transmitted through the ring system indicate an optical depth of 10(-1.3 +/-0.3) for the Cassini division. A phase integral of 1.02 +/- 0.06 is inferred for Rhea, which agrees with values for other icy bodies in the solar system. Rhea eclipse observations indicate the presence of surface materials with both high and low thermal inertias, the

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. STS-56 color infrared Earth observation of northern Argentina

    NASA Technical Reports Server (NTRS)

    1993-01-01

    STS-56 color infrared Earth observation taken aboard Discovery, Orbiter Vehicle (OV) 103, shows the agricultural frontier (rectangular field patterns) impinging on the natural grasslands (pampas) of northern Argentina. Note the sharp delineation between the upland agricultural areas (red and pink rectangles), and the lowland semi-arid grasslands or pampas (shown in violet and purple). In addition, several large smoke plumes associated with biomass burning are visible. These smoke plumes and their burn point sources are considered to be evident of extended agricultural preparations in the lowland pampas.

  17. 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.

  18. 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

  19. 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.

  20. Observable Measure of Quantum Coherence in Finite Dimensional Systems

    NASA Astrophysics Data System (ADS)

    Girolami, Davide

    2014-10-01

    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.

  1. 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.

  2. 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. PMID:25379903

  3. 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.

  4. 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.

  5. Venus Near-Infrared Spectra: SCIAMACHY-Observations and Modeling

    NASA Astrophysics Data System (ADS)

    Vasquez, Mayte; Schreier, Franz; Gimeno--Garcia, Sebastian; Gottwald, Manfred

    SCIAMACHY (Scanning Imaging Spectrometer for Atmospheric Chartography) onboard EN-VISAT successfully captured visible and near-infrared spectra of sunlight scattered and reflected from Venus atmosphere. Observations took place in March, when SCIAMACHY captured light mainly from the limb of Venus, and in June 2009, when a larger fraction of the planetary disk was illuminated representing a nadir viewing. Venus spectra were simulated using a line-by-line radiative transfer model, which also takes into account single scattering from atmospheric particles and molecules. Comparing SCIAMACHY's Venus observations with modeled spectra serves as a test for radiative transfer modeling of planetary atmospheres, an essential prereq-uisite for the search of living planets.

  6. Effective Radius Retrieval Using Microwave and Near-Infrared Observations

    NASA Astrophysics Data System (ADS)

    Schofield, R.; Daniel, J. S.; Solomon, S.; Miller, H. L.; Portmann, R. W.; Turner, D. D.

    2005-12-01

    The role that aerosols play in changing the radiative properties of clouds is uncertain, with even the sign of the forcing undetermined. The need for remotely sensing clouds is becoming more apparent with the desire to achieve a global estimate of the radiative forcing due to changes in clouds. A new technique of combining microwave and near-infrared spectroscopic measurements of liquid water path (LWP) and path integrated liquid water path (PLWP) respectively, to obtain effective radius information is outlined. Microwave measurements of brightness temperature are made routinely as part of the Aerosol and Radiation Measurement (ARM) program. Near-infrared measurements are conducted using spectroscopic measurements made in the wavelength region between 900 and 1700 nm. The effective radius of clouds is retrieved using an optimal estimation retrieval scheme that takes into account the measurements, their uncertainties, prior knowledge of the effective radius and its uncertainty. The technique is applied to ground-based observations of clouds made during September at Barrow, Alaska, 2004.

  7. XMM-Newton observations of three interacting luminous infrared galaxies

    SciTech Connect

    Mudd, Dale; Mathur, Smita; Guainazzi, Matteo; Piconcelli, Enrico; Nicastro, Fabrizio; Bianchi, Stefano; Komossa, S.; Vignali, Cristian; Lanzuisi, Giorgio; Fiore, Fabrizio; Maiolino, Roberto

    2014-05-20

    We investigate the X-ray properties of three interacting luminous infrared galaxy systems. In one of these systems, IRAS 18329+5950, we resolve two separate sources. A second and third source, IRAS 19354+4559 and IRAS 20550+1656, have only a single X-ray source detected. We compare the observed emission to point-spread function (PSF) profiles and determine that they are all consistent with the PSF, albeit with large uncertainties for some of our sources. We then model the spectra to determine soft (0.5-2 keV) and hard (2-10 keV) luminosities for the resolved sources and compare these to relationships found in the literature between infrared and X-ray luminosities for starburst galaxies. We obtain luminosities (0.5-10 keV) ranging from 1.7 to 7.3 × 10{sup 41} erg s{sup –1} for our systems. These X-ray luminosities are consistent with predictions for star-formation-dominated sources and thus are most likely due to starbursts, but we cannot conclusively rule out active galactic nuclei.

  8. 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.

  9. Reconciling the Infrared Catastrophe and Observations of SN 2011fe

    NASA Astrophysics Data System (ADS)

    Fransson, Claes; Jerkstrand, Anders

    2015-11-01

    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 57Co, finding both to be important at 1000 days.

  10. 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.

  11. 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.

  12. 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.

  13. Mid-Infrared observations of NGC 1068 with the Infrared Space Observatory

    NASA Astrophysics Data System (ADS)

    Le Floc'h, E.; Mirabel, I. F.; Laurent, O.; Charmandaris, V.; Gallais, P.; Sauvage, M.; Vigroux, L.; Cesarsky, C.

    2001-02-01

    We report on Mid-Infrared (MIR) observations of the Seyfert 2 galaxy NGC 1068, obtained with ISOCAM in low-resolution spectro-imaging mode. The spatial resolution ( ~ 5 arcsec) allows us to disentangle the circumnuclear starburst regions from the emission of the active galactic nucleus (AGN). The global spatial distribution of the Unidentified Infrared Bands (UIBs) is similar to the cold dust component, traced by the 450 mu m emission and the gaseous component obtained from the 12CO(1-0) map. However, a shift between the maximum of the UIB and 450 mu m emission is clearly seen in our maps. The UIBs in the MIR (5-16 mu m) originate almost exclusively from the starburst regions in the galactic disk with an emission peaking at the extremity of the stellar/gaseous bar at a distance of 1 kpc from the AGN. The spectrum of the nucleus is characterized over the whole 5-16 mu m range by a strong continuum which can be fitted with a power law of index alpha =-1.7. Moreover, the high [NeIII]/[NeII] ratio (gtapp 2.5) in the nuclear region argues for a hard radiation field from the AGN. Observations indicate that the AGN in NGC 1068 contributes less than ~ 5% to the total integrated UIB emission even though its hot dust continuum contributes as much as 75% to the total MIR flux. On the contrary, the nuclear contribution to the cold dust emission decreases considerably at submillimeter wavelengths and does not represent more than 25% of the total integrated emission at 450 mu m. Based on observations with the ISO satellite, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA.

  14. 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.

  15. 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.

  16. Recent development in infrared technologies at LETI for Earth observation

    NASA Astrophysics Data System (ADS)

    Yon, Jean Jacques; Destefanis, Gerard; Mottin, Eric

    2004-11-01

    In this paper we report on the CEA/LETI infrared laboratory activity in both HgCdTe cooled detectors and amorphous silicon uncooled microbolometers. An overview of the recent developments will be given while the future perspectives of these IR technologies will be highlighted in the context of space applications. The unique realization of a megapixel HgCdTe MWIR focal plane array with a 15μm pitch was completed in 2003. The electro-optical performances at LN temperature of this high resolution IRFPA will be given extensively. Beside this large 2D array achievement, CEA/LETI is strongly involved in the development of an innovative cooled multispectral technology that requires a specific HgCdTe growing process to achieve a stack of two dual band photodiodes in each pixel. This technology primarily relies on the molecular beam epitaxy (MBE) of a multiple (211)HgCdTe films grown on a lattice matched CdZnTe substrate. The device structure will be discussed as well as the elementary detectors characteristics which have been found to exhibit performances very close to those obtained in single colour detectors. The main electro-optical performances obtained at LN temperature of a two colours 128x128 IRCMOS FPA, 50μm pitch, operating sequentially within the MWIR (3-5μm) will be presented. The well establish availability of uncooled infrared detectors has opened new perspectives when miniaturization, weight, power and reliability are of paramount importance. Moreover the recent breakthrough of the performance of these sensors leads to new applications where enhanced resolution is required. The article will review the state of the art of CEA/LETI uncooled IR technology through various examples of focal plane arrays and the future trends of this uncooled technology will be considered. The trade-off between thermal resolution and time constant which is a critical parameter for earth observation will be largely discussed.

  17. 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.

  18. 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.

  19. 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.

  20. Local Luminous Infrared Galaxies. I. Spatially Resolved Observations with the Spitzer Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

    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 μm 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 μm and [Ne III]15.56 μm emissions. The behavior of the integrated PAH emission and 9.7 μm silicate feature is similar to that of local starburst galaxies. We also find that the minima of the [Ne III]15.56 μm/[Ne II]12.81 μm 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 μm/[Ne II]12.81 μm 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 μm PAH emission appears more extended than the dust 5.5 μm continuum emission. We find a dependency of the 11.3 μm PAH/7.7 μm PAH and [Ne II]12.81 μm/11.3 μm PAH ratios with the age of the stellar populations. Smaller and larger ratios, respectively, indicate recent star formation. The estimated warm (300 K observations made with the Spitzer Space Telescope, which is operated by the Jet

  1. 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.

    2011-01-01

    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 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 range of spectrum. In current work, a new method to retrieve AOT 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 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, 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 the region show a clear increase of AOT in the

  2. 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

  3. Infrared Observations of G0.18-0.04

    NASA Astrophysics Data System (ADS)

    Simpson, Janet P.; Colgan, Sean W. J.; Cotera, Angela S.; Erickson, Edwin F.; Haas, Michael R.; Morris, Mark; Rubin, Robert H.

    1997-10-01

    The Galactic center H II region, G0.18-0.04, also known as the ``Sickle,'' is located where the nonthermal ``Arc'' crosses the Galactic plane. The Sickle appears to be the ionized edge of a dense molecular cloud. The source of ionization has been ascribed to both the interaction of the cloud with the magnetic field of the Arc and to the hot stars in the adjacent cluster, AFGL 2004, also known as the ``Quintuplet Cluster.'' This paper addresses the relative locations of the stars, the ionized and molecular gas, and the sources of gas excitation and dust heating. The far-infrared forbidden lines of [S III] 18.7 and 33.5 μm, [Si II] 34.8 μm, [Ne III] 36.0 μm, [O III] 51.8 and 88.4 μm, [N III] 57.3 μm, [O I] 63.2 and 146 μm, [C II] 158 μm, and [N II] 205 μm and the adjacent continua were observed with NASA's Kuiper Airborne Observatory at 11 positions around G0.18-0.04, including G0.15-0.05, also known as the ``Pistol.'' The beam size was 40"-60". The electron density, the ionic abundances, and the ionization structure of the H II region were estimated from the doubly ionized line fluxes. The density and radiation field found in the photodissociation region (PDR) between the H II region and the molecular cloud were estimated from the [C II] and [O I] line fluxes and the far-infrared continuum. The ionization structure and the PDR properties were compared to shell models of H II regions with varying distances from their exciting stars. The agreement of observations and models indicates that the hot stars of AFGL 2004 are the likely source of ionization of the Sickle. Additional hot stars are necessary to ionize the more outlying positions. However, the low ionization and high PDR radiation field of the Pistol imply that it cannot be as close to AFGL 2004 as is indicated by its proximity on the sky. Instead, the Pistol is probably ionized by the luminous blue variable candidate, Pistol Source A. The extinction to the region was estimated from the IRAS low

  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. Near-infrared observations of PSR J1357-6429

    NASA Astrophysics Data System (ADS)

    Zyuzin, D.; Zharikov, S.; Shibanov, Yu.; Danilenko, A.; Mennickent, R. E.; Kirichenko, A.

    2016-01-01

    PSR J1357-6429 is a young radio pulsar that has been detected in the X-ray and γ-ray bands. We present high spatial resolution near-infrared imaging of the pulsar field in the J, H and Ks bands obtained using the VLT/NaCo with the Adaptive Optic system. We found a faint source at the most precise pulsar radio position, which we propose as the pulsar near-infrared counterpart candidate. It is confidently detected in the J and Ks bands, with J = 23.51 ± 0.24 and Ks = 21.82 ± 0.25. There is a hint of the source in the H band, with an upper limit H > 22.8. The dereddened source fluxes are compatible with the extrapolation of the pulsar X-ray spectrum towards the near-infrared. If the candidate is the true counterpart, this property means that PSR J1357-6429 would be similar to the nearby middle-age pulsar PSR B0656+14. In this case, both pulsars demonstrate an unusually high near-infrared efficiency relative to the X-ray efficiency as compared with other pulsars detected in these two ranges.

  6. 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.

  7. 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.

  8. 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.

  9. Infrared observations of contaminants from Shuttle flight 51-F

    NASA Technical Reports Server (NTRS)

    Koch, D. G.; Fazio, G. G.; Melnick, G.; Hoffmann, W.; Rieke, G.; Simpson, J.; Witteborn, F.

    1987-01-01

    A small helium-cooled infrared telescope, IRT, was flown on the Shuttle in July/August 1985. The principal astrophysical objectives were to measure the large scale structure of sources and the background radiation. A cold shutter was incorporated to permit absolute flux measurements. Additionally, the engineering objectives included setting upper limits on the infrared radiation from the local environment. Even though the local background overwhelmed the astrophysical background, astronomical sources were still detectable superimposed on this background radiation. Data are presented covering the spectral range from 2 microns to 120 microns. The spatial, spectral, and temporal variations are described. Based on the spectral character and variability in different wavelength bands, the background radiation does not appear to have a single origin. In this paper, the results on the Shuttle environment are presented.

  10. 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.

  11. Visible and infrared imaging radiometers for ocean observations

    NASA Technical Reports Server (NTRS)

    Barnes, W. L.

    1977-01-01

    The current status of visible and infrared sensors designed for the remote monitoring of the oceans is reviewed. Emphasis is placed on multichannel scanning radiometers that are either operational or under development. Present design practices and parameter constraints are discussed. Airborne sensor systems examined include the ocean color scanner and the ocean temperature scanner. The costal zone color scanner and advanced very high resolution radiometer are reviewed with emphasis on design specifications. Recent technological advances and their impact on sensor design are examined.

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. Hydration of lysozyme as observed by infrared spectrometry.

    PubMed

    Liltorp, K; Maréchal, Y

    2005-11-01

    Infrared spectra of a film of lysozyme 3 mum thick, immersed in an atmosphere displaying a relative humidity, or hygrometry, which spans the whole range from 0 to 1 at room temperature, are recorded. The evolution of the spectra with this relative humidity is quantitatively analyzed on the basis of a newly proposed method. It allows the precise measurement of the quantity of water that remains embedded inside the dried sample at each stage of hydration, and the definition, in terms of chemical reactions of the three hydration mechanisms that correspond to the three hydration spectra on which all experimental spectra can be decomposed. With respect to preceding similar studies, some refinements are introduced that allow improvement of the interpretation, but that also raise some new questions, which mainly concern the structure of the hydrogen-bond network around the carbonyl peptide groups. PMID:15986502

  17. Vibrational mode assignment of finite temperature infrared spectra using the AMOEBA polarizable force field.

    PubMed

    Thaunay, Florian; Dognon, Jean-Pierre; Ohanessian, Gilles; Clavaguéra, Carine

    2015-10-21

    The calculation of infrared spectra by molecular dynamics simulations based on the AMOEBA polarizable force field has recently been demonstrated [Semrouni et al., J. Chem. Theory Comput., 2014, 10, 3190]. While this approach allows access to temperature and anharmonicity effects, band assignment requires additional tools, which we describe in this paper. The Driven Molecular Dynamics approach, originally developed by Bowman, Kaledin et al. [Bowman et al. J. Chem. Phys., 2003, 119, 646, Kaledin et al. J. Chem. Phys., 2004, 121, 5646] has been adapted and associated with AMOEBA. Its advantages and limitations are described. The IR spectrum of the Ac-Phe-Ala-NH2 model peptide is analyzed in detail. In addition to differentiation of conformations by reproducing frequency shifts due to non-covalent interactions, DMD allows visualizing the temperature-dependent vibrational modes.

  18. Observed asteroid surface in the infrared: more than meets the eye

    NASA Astrophysics Data System (ADS)

    Nugent, Carolyn; Mainzer, Amy K.; Masiero, Joseph R.; Wright, Edward L.; Bauer, James M.; Grav, Tommy; Kramer, Emily A.; Sonnett, Sarah M.

    2016-10-01

    Most thermal IR observations of asteroids are unresolved. We consider what fraction of an asteroid's surface area contributes the bulk of the emitted thermal flux by computing the temperature of two model asteroids of different shapes over a range of thermal parameters. The resulting observed surface in the infrared is often different than the area observed in visible wavelengths. In some cases, only 12% of the surface contributes the majority of thermally emitted flux, when the object is observed at opposition. Calculating observed surface area in the infrared ensures that results from thermophysical modeling are interpreted accurately.

  19. 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.

  20. Saturn's atmospheric composition from observations by the Cassini/Composite Infrared Spectrometer

    NASA Astrophysics Data System (ADS)

    Abbas, Mian; Young, Madison M.; Leclair, Andre C.; Achterberg, Richard K.; Flasar, F. Michael; Kunde, Virgil G.

    Thermal emission infrared observations of Saturn's atmosphere have been made by the Compos-ite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft since its insertion into Saturn's orbit on July 2nd, 2004. The measurements made in both limb and nadir mode of observa-tions consist of infrared spectra in the 10-1400 cm-1 region with a variable spectral resolution of 0.53 cm-1 and 2.8 cm-1 , and exhibit rotational and vibrational spectral features that may be analyzed for retrieval of the thermal structure and constituent distribution of Saturn's at-mosphere. 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.

  1. 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.

  2. Postdispersion system for astronomical observations with Fourier transform spectrometers in the thermal infrared

    NASA Technical Reports Server (NTRS)

    Wiedermann, Guenter; Jennings, D. E.; Hanel, R. H.; Kunde, V. G.; Moseley, S. H.

    1989-01-01

    A postdispersion system for astronomical observations with Fourier transform spectrometers in the thermal infrared has been developed which improves the sensitivity of radiation noise limited observations by reducing the spectral range incident on the detector. Special attention is given to the first-generation blocked impurity band detector. Planetary, solar, and stellar observations are reported.

  3. Infrared observations of small solar-system bodies

    NASA Astrophysics Data System (ADS)

    Brown, R. H.

    1988-08-01

    A major accomplishment during last year is the recongition of and modeling of the solid-state greenhouse effect for icy satellites. Recent observations of eclipse reappearances suggest that this effect may in fact be observed on Europa and Ganymede. Also the PI has obtained important new data on Europa and Enceladus. Evidence for the transient presence of a volatile, perhaps NH3, OH, on Europa has been obtained. Newly obtained spectra of Enceladus suggest that it does not at present have ammonia or methane in detectable quantities on its surface.

  4. Infrared observations of small solar-system bodies

    NASA Technical Reports Server (NTRS)

    Brown, R. H.

    1988-01-01

    A major accomplishment during last year is the recongition of and modeling of the solid-state greenhouse effect for icy satellites. Recent observations of eclipse reappearances suggest that this effect may in fact be observed on Europa and Ganymede. Also the PI has obtained important new data on Europa and Enceladus. Evidence for the transient presence of a volatile, perhaps NH3, OH, on Europa has been obtained. Newly obtained spectra of Enceladus suggest that it does not at present have ammonia or methane in detectable quantities on its surface.

  5. 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

    1995-03-01

    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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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. PMID:26651750

  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. 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.

  14. 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.

  15. 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.

  16. Near infrared observations of quasars with extended ionized envelopes

    NASA Astrophysics Data System (ADS)

    Márquez, I.; Durret, F.; Petitjean, P.

    1999-02-01

    We have observed a sample of 15 and 8 quasars with redshifts between 0.11 and 0.87 (mean value 0.38) in the J and K' bands respectively. Eleven of the quasars were previously known to be associated with extended emission line regions. After deconvolution of the image, substraction of the PSF when possible, and identification of companions with the help of HST archive images when available, extensions are seen for at least eleven quasars. However, average profiles are different from that of the PSF in only four objects, for which a good fit is obtained with an r(1/4) law, suggesting that the underlying galaxies are ellipticals. Redshifts were available in the literature for surrounding objects in five quasar fields. For these objects, one to five companion galaxies were found. One quasar even belongs to a richness class 1 cluster. Most other quasars in our sample have nearby galaxies in projection which may also be companions. Environmental effects are therefore probably important to account for the properties of these objects. Based on data obtained at the European Southern Observatory, La Silla, Chile. Also based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute; STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France and of the NASA/IPAC extragalactic database (NED), which is operated by the Jet Propulsion Laboratory, Caltech under contract with the National Aeronautics and Space Administration.

  17. VizieR Online Data Catalog: Catalog of Infrared Observations, Edition 5 (Gezari+ 1999)

    NASA Astrophysics Data System (ADS)

    Gezari, D. Y.; Pitts, P. S.; Schmitz, M.

    1999-07-01

    The Catalog of Infrared Observations and its associated data base comprise a summary of infrared astronomical observations published in the scientific literature from 1965 through 1997 in the wavelength range 1 micrometer - 1 mm. The database contains infrared observational data for sources outside the Solar System, constructed through a search of the most active scientific journals, IR surveys and catalogs. To date, about 6200 journal articles and 10 major survey catalogs have been included in the data base, which contains 374,653 individual observations of about 62,000 different infrared sources. More than 8,000 of these sources are identifiable with visible objects. The bibliographical files link observations in the catalog with the original articles published in the literature. References give the standard information plus full titles. The Index of Infrared Source Positions is ordered alphabetically by source name and can be used to quickly locate sources in the position-ordered catalog. For sources with no published IR source position, a nominal position may have been given based on other sources. Nominal positions are usually the best available, but not necessarily the true IR positions. Nominal position references are indicated in the index. (7 data files).

  18. VizieR Online Data Catalog: Catalog of Infrared observations, Edition 3.5 (Gezari+ 1996)

    NASA Astrophysics Data System (ADS)

    Gezari, D. Y.; Pitts, P. S.; Schmitz, M.; Mead, J. M.

    1996-10-01

    The Catalog of Infrared Observations and its associated data base comprise a summary of infrared astronomical observations published in the scientific literature from 1965 through 1992 in the wavelength range 1 micrometer - 1 mm. The database contains infrared observational data for sources outside the Solar System, constructed through a search of the most active scientific journals, IR surveys and catalogs. To date, about 5100 journal articles and 10 major survey catalogs have been included in the data base, which contains more than 256000 individual observations of about 11500 different infrared sources. More than 8000 of these sources are identifiable with visible objects. The bibliographical files link observations in the catalog with the original articles published in the literature. References give the standard information plus full titles. The Index of Infrared Source Positions is ordered alphabetically by source name and can be used to quickly locate sources in the position-ordered catalog. For sources with no published IR source position, a nominal position may have been given based on other sources. Nominal positions are usually the best available, but not necessarily the true IR positions. Nominal position references are indicated in the index. (6 data files).

  19. VizieR Online Data Catalog: Catalog of Infrared observations, 3rd Edition (Gezari+ 1993)

    NASA Astrophysics Data System (ADS)

    Gezari, D. Y.; Schmitz, M.; Pitts, P. S.; Mead, J. M.

    1994-03-01

    The Catalog of Infrared Observations and its associated data base comprise a summary of infrared astronomical observations published in the scientific literature from 1965 through 1990 in the wavelength range 1 micrometer - 1 mm. The database contains infrared observational data for sources outside the Solar System, constructed through a search of the most active scientific journals, IR surveys and catalogs. To date, about 4500 journal articles and 10 major survey catalogs have been included in the data base, which contains more than 205000 individual observations of about 11500 different infrared sources. More than 8000 of these sources are identifiable with visible objects. The bibliographical files link observations in the catalog with the original articles published in the literature. References give the standard information plus full titles. The Index of Infrared Source Positions is ordered alphabetically by source name and can be used to quickly locate sources in the position-ordered catalog. For sources with no published IR source position, a nominal position may have been given based on other sources. Nominal positions are usually the best available, but not necessarily the true IR positions. Nominal position references are indicated in the index. (6 data files).

  20. VizieR Online Data Catalog: Catalog of Infrared Observations, Edition 4 (CIO) (Gezari+ 1997)

    NASA Astrophysics Data System (ADS)

    Gezari, D. Y.; Pitts, P. S.; Schmitz, M.

    1998-02-01

    The Catalog of Infrared Observations and its associated data base comprise a summary of infrared astronomical observations published in the scientific literature from 1965 through 1995 in the wavelength range 1 micrometer - 1 mm. The database contains infrared observational data for sources outside the Solar System, constructed through a search of the most active scientific journals, IR surveys and catalogs. To date, about 6195 journal articles and 10 major survey catalogs have been included in the data base, which contains more than 325,000 individual observations of about 55,000 different infrared sources. More than 8,000 of these sources are identifiable with visible objects. The bibliographical files link observations in the catalog with the original articles published in the literature. References give the standard information plus full titles. The Index of Infrared Source Positions is ordered alphabetically by source name and can be used to quickly locate sources in the position-ordered catalog. For sources with no published IR source position, a nominal position may have been given based on other sources. Nominal positions are usually the best available, but not necessarily the true IR positions. Nominal position references are indicated in the index. (7 data files).

  1. 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.

  2. 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.

  3. High speed Infrared imaging method for observation of the fast varying temperature phenomena

    NASA Astrophysics Data System (ADS)

    Moghadam, Reza; Alavi, Kambiz; Yuan, Baohong

    With new improvements in high-end commercial R&D camera technologies many challenges have been overcome for exploring the high-speed IR camera imaging. The core benefits of this technology is the ability to capture fast varying phenomena without image blur, acquire enough data to properly characterize dynamic energy, and increase the dynamic range without compromising the number of frames per second. This study presents a noninvasive method for determining the intensity field of a High Intensity Focused Ultrasound Device (HIFU) beam using Infrared imaging. High speed Infrared camera was placed above the tissue-mimicking material that was heated by HIFU with no other sensors present in the HIFU axial beam. A MATLAB simulation code used to perform a finite-element solution to the pressure wave propagation and heat equations within the phantom and temperature rise to the phantom was computed. Three different power levels of HIFU transducers were tested and the predicted temperature increase values were within about 25% of IR measurements. The fundamental theory and methods developed in this research can be used to detect fast varying temperature phenomena in combination with the infrared filters.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Comments on a peak of AlxGa1-xN observed by infrared reflectance

    NASA Astrophysics Data System (ADS)

    Marx, G.; Engelbrecht, J. A. A.; Lee, M. E.; Wagener, M. C.; Henry, A.

    2016-05-01

    AlxGa1-xN epilayers, grown on c-plane oriented sapphire substrates by metal organic chemical vapour deposition (MOCVD), were evaluated using FTIR infrared reflectance spectroscopy. A peak at ∼850 cm-1 in the reflectance spectra, not reported before, was observed. Possible origins for this peak are considered and discussed.

  10. Probing the interstellar medium in early-type galaxies with Infrared Space Oberservatory observations

    NASA Technical Reports Server (NTRS)

    Malhotra, S.; Hollenbach, D.; Helou, D.; Silbermann, N.; Valjavec, E.; Rubin, R.; Dale, D.; Hunter, D.; Lu, N.; Lord, S.; Dinerstein, H.; Thronson, H.

    2000-01-01

    Four IRAS-detected early-type galaxies were observed with the Infrared Space Observatory (ISO). With the exception of the 15 mu m image of NGC 1052, the mid-IR images of NGC 1052, NGC 1155, NGC 5866, and NGC 6958 at 4.5, 7, and 15 mu m show extended emission.

  11. Comparison of quarter-wave retarders over finite spectral and angular bandwidths for infrared polarimetric-imaging applications.

    PubMed

    Wadsworth, Samuel L; Boreman, Glenn D

    2011-12-20

    We compare three technological approaches for quarter-wave retarders within the context of polarimetric-imaging applications in the long-wave infrared (LWIR) spectrum. Performance of a commercial cadmium sulfide (CdS) crystalline waveplate, a multilayer meanderline structure, and a silicon (Si) form-birefringent retarder are evaluated under conditions of 8-12 μm broadband radiation emerging from an F/1 focusing objective. Metrics used for this comparison are the spectrally dependent axial ratio, retardance, and polarization-averaged power transmittance, which are averaged over the angular range of interest. These parameters correspond to the characteristics that would be observed at the focal-plane array (FPA) detector of an LWIR imaging polarimeter. PMID:22193200

  12. Comparison of quarter-wave retarders over finite spectral and angular bandwidths for infrared polarimetric-imaging applications.

    PubMed

    Wadsworth, Samuel L; Boreman, Glenn D

    2011-12-20

    We compare three technological approaches for quarter-wave retarders within the context of polarimetric-imaging applications in the long-wave infrared (LWIR) spectrum. Performance of a commercial cadmium sulfide (CdS) crystalline waveplate, a multilayer meanderline structure, and a silicon (Si) form-birefringent retarder are evaluated under conditions of 8-12 μm broadband radiation emerging from an F/1 focusing objective. Metrics used for this comparison are the spectrally dependent axial ratio, retardance, and polarization-averaged power transmittance, which are averaged over the angular range of interest. These parameters correspond to the characteristics that would be observed at the focal-plane array (FPA) detector of an LWIR imaging polarimeter.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. AKARI Observation of the Sub-degree Scale Fluctuation of the Near-infrared Background

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    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.

  18. 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.

  19. 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.

  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. 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.

  2. 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.

  3. 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.

  4. 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

  5. Near-Infrared Keck Interferometer and IOTA Closure Phase Observations of Wolf-Rayet stars

    NASA Astrophysics Data System (ADS)

    Rajagopal, J.; Wallace, D.; Barry, R.; Richardson, L. J.; Traub, W.; Danchi, W. C.

    We present first results from observations of a small sample of IR-bright Wolf-Rayet stars with the Keck Interferometer in the near-infrared, and with the IONIC beam three-telescope beam combiner at the Infrared and Optical Telescope Array (IOTA) observatory. The former results were obtained as part of shared-risk observations in commissioning the Keck Interferometer and form a subset of a high-resolution study of dust around Wolf-Rayet stars using multiple interferometers in progress in our group. The latter results are the first closure phase observations of these stars in the near-infrared in a separated telescope interferometer. Earlier aperture-masking observations with the Keck-I telescope provide strong evidence that dust-formation in late-type WC stars are a result of wind-wind collision in short-period binaries.Our program with the Keck interferometer seeks to further examine this paradigm at much higher resolution. We have spatially resolved the binary in the prototypical dusty WC type star WR 140. WR 137, another episodic dust-producing star, has been partially resolved for the first time, providing the first direct clue to its possible binary nature.We also include WN stars in our sample to investigate circumstellar dust in this other main sub-type of WRs. We have been unable to resolve any of these, indicating a lack of extended dust.Complementary observations using the MIDI instrument on the VLTI in the mid-infrared are presented in another contribution to this workshop.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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).

  11. 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.

  12. 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.

  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

    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.

  15. 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

  16. 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.

  17. 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.

  18. 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

    2015-06-01

    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.

  19. Dust around R Coronae Borealis Stars. I. Spitzer/Infrared Spectrograph Observations

    NASA Astrophysics Data System (ADS)

    García-Hernández, D. A.; Rao, N. Kameswara; Lambert, David L.

    2011-09-01

    Spitzer/infrared spectrograph (IRS) spectra from 5 to 37 μm for a complete sample of 31 R Coronae Borealis stars (RCBs) are presented. These spectra are combined with optical and near-infrared photometry of each RCB at maximum light to compile a spectral energy distribution (SED). The SEDs are fitted with blackbody flux distributions and estimates are made of the ratio of the infrared flux from circumstellar dust to the flux emitted by the star. Comparisons for 29 of the 31 stars are made with the Infrared Astronomical Satellite (IRAS) fluxes from three decades earlier: Spitzer and IRAS fluxes at 12 μm and 25 μm are essentially equal for all but a minority of the sample. For this minority, the IRAS to Spitzer flux ratio exceeds a factor of three. The outliers are suggested to be stars where formation of a dust cloud or dust puff is a rare event. A single puff ejected prior to the IRAS observations may have been reobserved by Spitzer as a cooler puff at a greater distance from the RCB. RCBs which experience more frequent optical declines have, in general, a circumstellar environment containing puffs subtending a larger solid angle at the star and a quasi-constant infrared flux. Yet, the estimated subtended solid angles and the blackbody temperatures of the dust show a systematic evolution to lower solid angles and cooler temperatures in the interval between IRAS and Spitzer. Dust emission by these RCBs and those in the LMC is similar in terms of total 24 μm luminosity and [8.0]-[24.0] color index.

  20. Far-infrared observations of the evolved H II region M16

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    The results of far infrared (FIR) observations of the larger H II region M16, associated with the young open star cluster NGC 6611, are discussed. Three FIR sources detected on an extended ridge of FIR emission within the scanned region are described. The observations confirm that M16 is an H II region in a late stage of evolution. The H II region has expanded and is now extremely density bounded, consisting of an extended region of ionized gas and a series of ionization fronts located at the surrounding molecular cloud boundaries nearest to the exciting OB star cluster. The FIR radiation arises from heated dust at these boundaries.

  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. 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.

  3. 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.

  4. 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.

  5. 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).

  6. 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.

  7. Observations of Resolved Stellar Populations with the JWST Near Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Gilbert, Karoline; Beck, Tracy L.; Karakla, Diane M.

    2015-01-01

    The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) will provide a multi-object spectroscopy mode through the four Micro-Shutter Arrays (MSAs). Each MSA 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 1 to 5 micrometers will open new parameter space for studies of galaxies and resolved stellar populations alike. We present a NIRSpec MSA observing scenario for obtaining spectroscopy of individual stars in external galaxies. We examine the multiplexing capability of the MSA as a function of the possible MSA configuration design choices, and investigate the primary sources of error in velocity measurements and the prospects for minimizing them. We discuss how this and other use cases are being used to guide development of the NIRSpec user interfaces, including proposal planning and pipeline calibrations.

  8. Observations of the Ca II infrared triplet in chromospherically active single and binary stars

    NASA Technical Reports Server (NTRS)

    Dempsey, Robert C.; Bopp, Bernard W.; Henry, Gregory W.; Hall, Douglas S.

    1993-01-01

    Spectroscopic observations of the Ca II infrared triplet (8498, 8542, 8662 A) have been obtained for 45 stars which are known or suspected to be chromospherically active. The sample includes both single and binary stars of spectral types from F2 to M5 spanning luminosity classes III, IV, and V. Several different types of activity diagnostics were measured, and their relative merits are discussed. Dependence of chromospheric emission upon rotation period, luminosity, temperature, and duplicity are analyzed. Synchronous binaries show a slight trend of increased emission with decreasing period while the asynchronous binaries show abnormally high activity levels for their rotation periods. Several stars exhibit rotationally modulated emission which is anticorrelated with the stellar brightness. Finally, estimates of chromospheric energy losses are presented with the result that the total loss in the infrared triplet is about twice that of the H and K lines.

  9. 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

  10. 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

  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. 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

  14. 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.

  15. Near-Infrared Spectroscopy of Warm Spitzer-observed Near-Earth Objects

    NASA Astrophysics Data System (ADS)

    Thomas, Cristina A.; Emery, J. P.; Trilling, D. E.; Delbo, M.; Hora, J. L.; Mueller, M.

    2013-10-01

    We have completed a spectroscopic observing campaign to complement the ExploreNEOs Warm Spitzer program. ExploreNEOs or “The Warm Spitzer NEO Survey: Exploring the history of the inner Solar System and near-Earth space” was allocated 500 hours over two years (2009-2011) to determine diameters and albedos for approximately 600 near-Earth objects using the 3.6 and 4.5 micron IRAC bands. We present the results of the SpeX component of our campaign. In order to increase our sample size we also include all near-infrared observations of ExploreNEOs targets in the MIT-UH-IRTF Joint Campaign for Spectral Reconnaissance. Our complete dataset includes 125 observations of 92 objects from our survey and 213 observations of 154 objects from the MIT survey. The combination of the two surveys includes near-infrared spectroscopy of 187 ExploreNEOs targets. We find no correlation between spectral band parameters and ExploreNEOs albedos and diameters. We identified all potential ordinary chondrites within our sample and determined likely ordinary chondrite types using the equations derived by Dunn et al. 2010. Our resulting proportions of H, L, and LL ordinary chondrites are different than those previously calculated for ordinary chondrite-like near-Earth objects and meteorite falls.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. The Atmospheric Infrared Sounder on the Earth Observing System - In-orbit spectral calibration

    NASA Technical Reports Server (NTRS)

    Aumann, H. H.

    1991-01-01

    The Atmospheric Infrared Sounder (AIRS) is a facility instrument on the Earth Observing System (EOS). The ability of AIRS to provide accurate temperature and moisture soundings with high vertical resolution depends critically on a very accurate spectral calibration. The routine in-orbit spectral calibration is accomplished with a Fabry-Perot plate with a fixed spacing of 360 microns. This paper discusses design, Signal-to-Noise, and temperature and alignment stability constraints which have to be met to achieve the required spectral calibration accuracy.

  2. 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.

  3. 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.

    2016-09-01

    We present multi-wavelength 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 one month, and recorded multiple transit events with depths varying between ˜20 to 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 to 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.

  4. 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.

  5. 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.

  6. Far-infrared observations of main sequence stars surrounded by dust shells

    NASA Technical Reports Server (NTRS)

    Harvey, Paul M.; Smith, Beverly J.; Difrancesco, J.

    1995-01-01

    We have used a 20-channel bolometer array on NASA's Kuiper Airborne Observatory to obtain photometry and size information for several main sequence stars surrounded by dust shells. The observations were made at 50 and/or 100 micrometers on flights based in Christchurch, New Zealand, in 1992, 1993. The stars include the 'Vega-like' star, Beta Pic, as well as two stars, HD 135344 and HD 139614, suggested by subsequent studies to belong possibly to the same class. The results of our observations are best interpreted as upper limits to the far-infrared sizes of the dust clouds around these stars. In addition to the basic size and flux measurements, we have fit simple, optically thin models to the Beta Pic data to explore the range of shell parameters consistent with our limits and with previous observations.

  7. 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.

  8. Jet-driving protostars identified from infrared observations of the Carina Nebula complex

    NASA Astrophysics Data System (ADS)

    Ohlendorf, H.; Preibisch, T.; Gaczkowski, B.; Ratzka, T.; Grellmann, R.; McLeod, A. F.

    2012-04-01

    Aims: Jets are excellent signposts for very young embedded protostars, so we want to identify jet-driving protostars as a tracer of the currently forming generation of stars in the Carina Nebula, which is one of the most massive galactic star-forming regions and which is characterised by particularly high levels of massive-star feedback on the surrounding clouds. Methods: We used archive data to construct large ( ≳ 2° × 2°) Spitzer IRAC mosaics of the Carina Nebula and performed a spatially complete search for objects with excesses in the 4.5 μm band, typical of shock-excited molecular hydrogen emission. We also identified the mid-infrared point sources that are the likely drivers of previously discovered Herbig-Haro jets and molecular hydrogen emission line objects. We combined the Spitzer photometry with our recent Herschel far-infrared data to construct the spectral energy distributions, and used the Robitaille radiative-transfer modelling tool to infer the properties of the objects. Results: The radiative-transfer modelling suggests that the jet sources are protostars with masses between ~1 M⊙ and ~10 M⊙ that are surrounded by circumstellar disks and embedded in circumstellar envelopes. Conclusions: The estimated protostar masses ≤10 M⊙ suggest that the current star-formation activity in the Carina Nebula is restricted to low- and intermediate-mass stars. More optical than infrared jets can be observed, indicating that star formation predominantly takes place close to the surfaces of clouds. 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 a contract with NASA, and on data collected by Herschel, an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  9. 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.

  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. Characterizing Ultraviolet and Infrared Observational Properties for Galaxies. II. Features of Attenuation Law

    NASA Astrophysics Data System (ADS)

    Mao, Ye-Wei; Kong, Xu; Lin, Lin

    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.

  12. 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.

  13. Titan's surface and troposphere, investigated with ground-based, near-infrared observations.

    PubMed

    Griffith, C A; Owen, T; Wagener, R

    1991-01-01

    New observations of Titan's near-infrared spectrum (4000-5000 cm-1) combined with points taken from Fink and Larson's (1979) spectrum (4000-12500 cm-1) provide information on Titan's haze, possible clouds, surface albedo, and atmospheric abundance of H2. In the near-infrared, the main features in Titan's spectrum result from absorption of solar radiation by CH4. The strength of this absorption varies considerably with wavelength, allowing us to probe various atmospheric levels down to the surface itself by choosing specific wavelengths for analysis. At 4715 cm-1, the pressure-induced S(1) fundamental band of H2 lies in the wings of CH4 bands. Based on current values for the CH4 line parameters, Titan's spectrum can be best interpreted with a volume mixing ratio of H2 between 0.5 and 1.0%. Our observations suggest the existence of an optically thin CH4 cloud layer. The optical depths that we derive for Titan's haze and clouds are small enough to allow us to sense the surface of Titan at 4900, 6250, and 7700 cm-1. The most plausible interpretation of the albedos determined at these wavenumbers suggests a surface dominated by "dirty" water ice. A global ethane ocean is not compatible with these albedos.

  14. 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.

  15. Near-Infrared and X-Ray Observations of XSS J12270-4859

    NASA Astrophysics Data System (ADS)

    Saitou, Kei; Tsujimoto, Masahiro; Ebisawa, Ken; Ishida, Manabu; Mukai, Koji; Nagayama, Takahiro; Nishiyama, Shogo; Gandhi, Poshak

    2011-11-01

    XSS J12270-4859 (J12270) is an enigmatic source of unknown nature. Previous studies revealed that the source has unusual X-ray temporal characteristics, including repetitive short-term flares, followed by spectral hardening, non-periodic dips, and dichotomy in activity; i.e., intervals filled with flares and those without. Together with a power-law X-ray spectrum, it is suggested to be a low-mass X-ray binary. In order to better understand the object, we present the results of our near-infrared (NIR) photometry and linear polarimetry observations as well as X-ray spectroscopy observations, which overlap with each other partially in time, taken respectively with the InfraRed Survey Facility (IRSF) and the Rossi X-ray Timing Explorer (RXTE). We detected several simultaneous NIR and X-ray flares for the first time. No significant NIR polarization was obtained. We assembled data taken with IRSF, RXTE, Suzaku, Swift, and other missions in the literature and compared the flare profile and the spectral energy distribution (SED) with some representative high-energy sources. Based on some similarities of the repetitive NIR and X-ray flaring characteristics and the broad SED, we argue that J12270 is reminiscent of microquasars with a synchrotron jet, which is at a very low-luminosity state of ≈ 10-4 Eddington luminosity for a stellar mass black hole or neutron star at a reference distance of 1 kpc.

  16. Mid-infrared spectrum of the zodiacal light observed with ISOPHOT

    NASA Astrophysics Data System (ADS)

    Leinert, Ch.; Ábrahám, P.; Acosta-Pulido, J.; Lemke, D.; Siebenmorgen, R.

    2002-10-01

    We present 29 mid-infrared spectra of the zodiacal light distributed over the sky. The observed 5.9-11.7 mu m spectral shapes are well represented by blackbody radiation with colour temperatures in the range of 255<= T<= 300 K. The spectra are smooth and featureless. The variation of the temperature can be explained by the geometrical distribution of dust in the inner solar system. This result indicates that although the interplanetary dust particles originate from discrete sources (comets, asteroids) the interplanetary cloud of today seems to be well mixed in terms of grain composition and size distribution. Based on observations with ISO, an ESA project with instruments funded by ESA member states (especially the PI countries France, Germany, The Netherlands and the UK) with participation of ISAS and NASA.

  17. Reanalysis of the Near-infrared Extragalactic Background Light Based on the IRTS Observations

    NASA Astrophysics Data System (ADS)

    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. High-Resolution Observations of the Infrared Spectrum of Neutral Neon

    PubMed Central

    Sansonetti, Craig J.; Blackwell, Marion M.; Saloman, E. B.

    2004-01-01

    We have observed the spectrum of neutral neon (Ne I) emitted by a microwave-excited electrodeless discharge lamp with the National Institute of Standards and Technology 2 m Fourier transform spectrometer. The spectra cover the regions 6929 Å to 11 000 Å with a resolution of 0.01 cm−1 and 11 000 Å to 47 589 Å with a resolution of 0.007 cm−1. We present a line list that includes more than 650 classified lines and provides an accurate and comprehensive description of the infrared spectrum. The response of the Fourier transform spectrometer was determined by using a radiometrically calibrated tungsten strip lamp, providing relative intensities that for moderate to strong lines are accurate to approximately 10 % over the entire range of the observations. The identities of many lines that were previously multiply classified are unambiguously resolved. PMID:27366619

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. The ionization structure of the Orion nebula: Infrared line observations and models

    NASA Technical Reports Server (NTRS)

    Simpson, J. P.; Rubin, R. H.; Erickson, E. F.; Haas, M. R.

    1986-01-01

    Observations of the (O III) 52 and 88 micron lines and the (N III) 57 micron line have been made at 6 positions and the (Ne III) 36 micron line at 4 positions in the Orion Nebula to probe its ionization structure. The measurements, made with a -40" diameter beam, were spaced every 45" in a line south from and including the Trapezium. The wavelength of the (Ne III) line was measured to be 36.013 + or - 0.004 micron. Electron densities and abundance ratios of N(++)/O(++) have been calculated and compared to other radio and optical observations. Detailed one component and two component (bar plus halo) spherical models were calculated for exciting stars with effective temperatures of 37 to 40,000K and log g = 4.0 and 4.5. Both the new infrared observations and the visible line measurements of oxygen and nitrogen require T sub eff approx less than 37,000K. However, the double ionized neon requires a model with T sub eff more than or equal to 39,000K, which is more consistent with that inferred from the radio flux or spectral type. These differences in T sub eff are not due to effects of dust on the stellar radiation field, but are probably due to inaccuracies in the assumed stellar spectrum. The observed N(++)/O(++) ratio is almost twice the N(+)/O(+) ratio. The best fit models give N/H = 8.4 x 10 to the -5 power, O/H = 4.0 x 10 to the -4 power, and Ne/H = 1.3 x 10 to the -4 power. Thus neon and nitrogen are approximately solar, but oxygen is half solar in abundance. From the infrared O(++) lines it is concluded that the ionization bar results from an increase in column depth rather than from a local density enhancement.

  6. 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.

  7. Comparison of human observer and algorithmic target detection in nonurban forward-looking infrared imagery

    NASA Astrophysics Data System (ADS)

    Weber, Bruce A.

    2005-07-01

    We have performed an experiment that compares the performance of human observers with that of a robust algorithm for the detection of targets in difficult, nonurban forward-looking infrared imagery. Our purpose was to benchmark the comparison and document performance differences for future algorithm improvement. The scale-insensitive detection algorithm, used as a benchmark by the Night Vision Electronic Sensors Directorate for algorithm evaluation, employed a combination of contrastlike features to locate targets. Detection receiver operating characteristic curves and observer-confidence analyses were used to compare human and algorithmic responses and to gain insight into differences. The test database contained ground targets, in natural clutter, whose detectability, as judged by human observers, ranged from easy to very difficult. In general, as compared with human observers, the algorithm detected most of the same targets, but correlated confidence with correct detections poorly and produced many more false alarms at any useful level of performance. Though characterizing human performance was not the intent of this study, results suggest that previous observational experience was not a strong predictor of human performance, and that combining individual human observations by majority vote significantly reduced false-alarm rates.

  8. Simulating satellite infrared sounding retrievals in support of Observing System Simulation Experiments (OSSEs)

    NASA Astrophysics Data System (ADS)

    Pagano, Thomas S.; Mathews, William; Irion, Frederick W.; Sturm, Erick J.

    2014-09-01

    A new set of Observing System Simulation Experiments (OSSEs) are underway to assess the impact of higher spatial and temporal resolution sounding on hurricane forecast accuracy. To support these studies, we have developed an OSSE retrieval simulation system. The system uses a simulated satellite orbit track to provide sample locations and footprint area of the infrared sounder configuration to be simulated over the region of interest. The data to be sampled are an OSSE nature run developed by the NOAA Atlantic Oceanographic Meteorological Laboratory (AOML) and the University of Miami (UM). The nature run is sampled at the sounder locations and integrated over the sounder footprint area. The resulting averaged profiles are smoothed vertically with simulated averaging kernels for the Atmospheric Infrared Sounder (AIRS) using a linear retrieval simulation to produce calculated temperature and water vapor profiles. With reasonable fidelity, the sampled and smoothed profiles simulate the retrievals we can expect from a sounder like AIRS for the orbit and sampling configurations under test. Three instruments were simulated corresponding to the AIRS 45×45km footprint in LEO, a hypothetical sounder at 2×2km footprint in LEO, and a hypothetical GEO sounder at 5×5km regional and 10km × 10km full disk footprint sizes. RMS error relative to the nature run is calculated to demonstrate the error characteristics of the simulation system. The simulated retrievals as a result of this effort are currently being assessed by NOAA AOML in an OSSE study to determine the impact of advanced hyperspectral infrared sounders on hurricane forecast improvement.

  9. OISTER Optical and Near-Infrared Observations of Type Iax Supernova 2012Z

    NASA Astrophysics Data System (ADS)

    Yamanaka, Masayuki; Maeda, Keiichi; Kawabata, Koji S.; Tanaka, Masaomi; Tominaga, Nozomu; Akitaya, Hiroshi; Nagayama, Takahiro; Kuroda, Daisuke; Takahashi, Jun; Saito, Yoshihiko; Yanagisawa, Kenshi; Fukui, Akihiko; Miyanoshita, Ryo; Watanabe, Makoto; Arai, Akira; Isogai, Mizuki; Hattori, Takashi; Hanayama, Hidekazu; Itoh, Ryosuke; Ui, Takahiro; Takaki, Katsutoshi; Ueno, Issei; Yoshida, Michitoshi; Ali, Gamal B.; Essam, Ahmed; Ozaki, Akihito; Nakao, Hikaru; Hamamoto, Ko; Nogami, Daisaku; Morokuma, Tomoki; Oasa, Yumiko; Izumiura, Hideyuki; Sekiguchi, Kazuhiro

    2015-06-01

    We report observations of the Type Iax supernova (SN Iax) 2012Z at optical and near-infrared (NIR) wavelengths from immediately after the explosion until ˜260 days after the maximum luminosity using the Optical and Infrared Synergetic Telescopes for Education and Research Target-of-Opportunity program and the Subaru Telescope. We found that the NIR light curve evolutions and color evolutions are similar to those of SNe Iax 2005hk and 2008ha. The NIR absolute magnitudes ({M}J˜ -18.1 mag and {M}H˜ -18.3 mag) and the rate of decline of the light curve (Δ m15(B) =\\1.6+/- 0.1 mag) are very similar to those of SN 2005hk ({M}J˜ -17.7 mag, {M}H˜ -18.0 mag, and Δ m15(B) ˜ 1.6 mag), yet differ significantly from SNe 2008ha and 2010ae (MJ ˜ -14 to -15 mag and Δ m15(B) ˜ 2.4-2.7 mag). The estimated rise time is 12.0 ± 3.0 days, which is significantly shorter than that of SN 2005hk or any other SNe Ia. The rapid rise indicates that the 56Ni distribution may extend into the outer layer or that the effective opacity may be lower than that in normal SNe Ia. The late-phase spectrum exhibits broader emission lines than those of SN 2005hk by a factor of six to eight. Such high velocities of the emission lines indicate that the density profile of the inner ejecta extends more than that of SN 2005hk. We argue that the most favored explosion scenario is a “failed deflagration” model, although the pulsational delayed detonations is not excluded. Based on data collected with the Optical and Infrared Synergetic Telescopes for Education and Research (OISTER) and with the Subaru Telescope operated by the National Astronomical Observatory of Japan.

  10. 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.

  11. 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

  12. 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.

  13. Thermal infrared observations of lava flows during the 1984 Mauna Loa eruption

    NASA Astrophysics Data System (ADS)

    Pieri, D. C.; Gillespie, R.; Kahle, A. B.; Kahle, J.; Baloga, S. M.

    1985-04-01

    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.

  14. 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

    1992-09-01

    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.

  15. 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

    1992-09-01

    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. PMID:17738279

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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).

  3. Observation of correlated electronic decay in expanding clusters triggered by near-infrared fields.

    PubMed

    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

  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. Infrared Observations of the Quintuplet Proper Members using SOFIA/FORCAST and Gemini/TReCS

    NASA Astrophysics Data System (ADS)

    Hankins, M. J.; Lau, R. M.; Morris, M. R.; Sanchez-Bermudez, J.; Pott, J. U.; Adams, J. D.; Herter, T. L.

    2016-08-01

    Since their discovery, the Quintuplet proper members (QPMs) have been somewhat mysterious in nature. Originally dubbed the “cocoon stars” due to their cool featureless spectra, high-resolution near-infrared imaging observations have shown that at least two of the objects exhibit “pinwheel” nebulae consistent with binary systems with a carbon-rich Wolf–Rayet star and O/B companion. In this paper, we present 19.7, 25.2, 31.5, and 37.1 μm observations of the QPMs (with an angular resolution of 3.2″–3.8″) taken with the Faint Object Infrared Camera for the SOFIA Telescope (FORCAST) in conjunction with high-resolution (˜0.1″–0.2″) images at 8.8 and 11.7 μm from the Thermal-Region Camera Spectrograph (TReCS). DUSTY models of the thermal dust emission of two of the four detected QPMs, Q2 and Q3, are fitted by radial density profiles that are consistent with constant mass-loss rates ({ρ }d\\propto {r}-2). For the two remaining sources, Q1 and Q9, extended structures (˜1″) are detected around these objects in high-resolution imaging data. Based on the fitted dust masses, Q9 has an unusually large dust reservoir ({M}{{d}}={1.3}-0.4+0.8× {10}-3{M}ȯ ) compared to typical dusty Wolf–Rayet stars, which suggests that it may have recently undergone an episode of enhanced mass loss.

  6. Infrared Observations of the Quintuplet Proper Members using SOFIA/FORCAST and Gemini/TReCS

    NASA Astrophysics Data System (ADS)

    Hankins, M. J.; Lau, R. M.; Morris, M. R.; Sanchez-Bermudez, J.; Pott, J. U.; Adams, J. D.; Herter, T. L.

    2016-08-01

    Since their discovery, the Quintuplet proper members (QPMs) have been somewhat mysterious in nature. Originally dubbed the “cocoon stars” due to their cool featureless spectra, high-resolution near-infrared imaging observations have shown that at least two of the objects exhibit “pinwheel” nebulae consistent with binary systems with a carbon-rich Wolf-Rayet star and O/B companion. In this paper, we present 19.7, 25.2, 31.5, and 37.1 μm observations of the QPMs (with an angular resolution of 3.2″-3.8″) taken with the Faint Object Infrared Camera for the SOFIA Telescope (FORCAST) in conjunction with high-resolution (˜0.1″-0.2″) images at 8.8 and 11.7 μm from the Thermal-Region Camera Spectrograph (TReCS). DUSTY models of the thermal dust emission of two of the four detected QPMs, Q2 and Q3, are fitted by radial density profiles that are consistent with constant mass-loss rates ({ρ }d\\propto {r}-2). For the two remaining sources, Q1 and Q9, extended structures (˜1″) are detected around these objects in high-resolution imaging data. Based on the fitted dust masses, Q9 has an unusually large dust reservoir ({M}{{d}}={1.3}-0.4+0.8× {10}-3{M}⊙ ) compared to typical dusty Wolf-Rayet stars, which suggests that it may have recently undergone an episode of enhanced mass loss.

  7. 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.

  8. 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.

  9. Distribution of Methane in the tropics from MetOp/IASI hyperspectral infrared observations

    NASA Astrophysics Data System (ADS)

    Delphine, Nobileau; Cyril, Crevoisier; Peter, Bergamaschi; Alain, Chedin; Raymond, Armante; Noelle, Scott

    2010-05-01

    The Infrared Atmospheric Sounding Interferometer (IASI) launched onboard the European MetOp platform in October 2006 provides new information on methane (CH4) distribution in the mid-troposphere and gives the opportunity to follow the recent evolution of CH4 concentration. In May 2010, 34 months of IASI observations will have been interpreted in terms of methane distribution. With its high spectral resolution, IASI provides ten channels in the 7.7 μm band highly sensitive to CH4 with reduced sensitivities to other atmospheric variables. We use coupled observations in the thermal infrared from IASI, and in the microwave from the Advanced Microwave Sounding Unit (AMSU), also launched onboard MetOp, to retrieve mid-to-upper tropospheric contents of methane (CH4) in clear-sky conditions, in the tropics. Thermal observations, sensitive to both temperature and CH4, are used in conjunction with microwave observations, only sensitive to temperature, to decorrelate both signals through a non-linear inference scheme based on neural networks. A key point of this approach is that no use is made of prior information in terms of gas seasonality, trend, or geographical patterns. The precision of the IASI retrieval is estimated to be about 1%. Features of the retrieved CH4 space-time distributions include: (1) a CH4 trend of ~10 ppbv.yr-1 in the last couple of years, which confirms the recent increase of methane detected at surface stations; (2) a strong seasonal cycle in the northern tropics, and a lower seasonal cycle in the southern tropics, in agreement with in-situ measurements; (3) a latitudinal decrease from 20 N to 20 S lower than what is observed at the surface but in agreement with tropospheric aircraft measurements; (4) geographical patterns in good agreement with simulations from the TM5 atmospheric transport and chemistry model; (5) signatures of CH4 emissions transported to the troposphere such as a large plume of elevated tropospheric methane south of the Asian

  10. Finite temperature effect in infrared-improved AdS/QCD model with back reaction of bulk vacuum

    NASA Astrophysics Data System (ADS)

    Cui, Ling-Xiao; Fang, Zhen; Wu, Yue-Liang

    2016-06-01

    Based on an IR-improved soft-wall AdS/QCD model for mesons, which provides a consistent prediction for the mass spectra of resonance scalar, pseudoscalar, vector and axial-vector mesons, we investigate its finite temperature effect. By analyzing the spectral function of mesons and fitting it with a Breit-Wigner form, we perform an analysis for the critical temperature of mesons. The back-reaction effects of bulk vacuum are considered and the thermal mass spectral function of resonance mesons is calculated based on the back-reaction improved action. A reasonable melting temperature is found to be T c ≈ 150 ± 7 MeV, which is consistent with the recent results from lattice QCD simulations. Supported by National Nature Science Foundation of China (NSFC)(10975170, 10905084, 10821504), and Project of Knowledge Innovation Program (PKIP) of Chinese Academy of Science

  11. 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

  12. 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.

  13. Observations of Ice Nucleation and Propagation in Plants Using Infrared Video Thermography.

    PubMed

    Wisniewski, M.; Lindow, S. E.; Ashworth, E. N.

    1997-02-01

    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.

  14. 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.

  15. Observations of Ice Nucleation and Propagation in Plants Using Infrared Video Thermography.

    PubMed

    Wisniewski, M.; Lindow, S. E.; Ashworth, E. N.

    1997-02-01

    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

  16. 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.

  17. 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

  18. Determination of physical properties of the Asteroid (41) Daphne from interferometric observations in the thermal infrared

    NASA Astrophysics Data System (ADS)

    Matter, Alexis; Delbo, Marco; Ligori, Sebastiano; Crouzet, Nicolas; Tanga, Paolo

    2011-09-01

    We describe interferometric observations of the Asteroid (41) Daphne in the thermal infrared obtained with the Mid-Infrared Interferometric Instrument (MIDI) and the Auxiliary Telescopes (ATs) of the European Southern Observatory (ESO) Very Large Telescope Interferometer (VLTI). We derived the size and the surface thermal properties of (41) Daphne by means of a thermophysical model (TPM), which is used for the interpretation of interferometric data for the first time. From our TPM analysis, we derived a volume equivalent diameter for (41) Daphne of 189 km, using a non-convex 3-D shape model derived from optical lightcurves and adaptive optics images (B. Carry, private communication). On the other hand, when using the convex shape of Kaasalainen et al. (Kaasalainen, M., Mottola, S., Fulchignoni, M. [2002]. Icarus 159, 369-395) in our TPM analysis, the resulting volume equivalent diameter of (41) Daphne is between 194 and 209 km, depending on the surface roughness. The shape of the asteroid is used as an a priori information in our TPM analysis. No attempt is made to adjust the shape to the data. Only the size of the asteroid and its thermal parameters such as, albedo, thermal inertia and roughness are adjusted to the data. We estimated our model systematic uncertainty to be of 4% and of 7% on the determination of the asteroid volume equivalent diameter depending on whether the non-convex or the convex shape is used, respectively. In terms of thermal properties, we derived a value of the surface thermal inertia smaller than 50 J m -2 s -0.5 K -1 and preferably in the range between 0 and ˜30 J m -2 s -0.5 K -1. Our TPM analysis also shows that Daphne has a moderate macroscopic surface roughness.

  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. 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.

  1. 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.

  2. 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.

  3. Nonlinear sediment response during the 1994 Northridge earthquake: Observations and finite source simulations

    SciTech Connect

    Field, E.H.; Zeng, Y.; Johnson, P.A.; Beresnev, I.A.

    1998-11-01

    We have addressed the long-standing question regarding nonlinear sediment response in the Los Angeles region by testing whether sediment amplification was similar between the Northridge earthquake and its aftershocks. Comparing the weak- and strong-motion site response at 15 sediment sites, we find that amplification factors were significantly less for the main shock implying systematic nonlinearity. The difference is largest between 2 and 4 Hz (a factor of 2), and is significant at the 99{percent} confidence level between 0.8 and 5.5 Hz. The inference of nonlinearity is robust with respect to the removal of possibly anomalous sediment sites and how the reference-site motion is defined. Furthermore, theoretical ground-motion simulations show no evidence of any bias from finite source effects during the main shock. Nonlinearity is also suggested by the fact that the four sediment sites that contain a clear fundamental resonance for the weak motion exhibit a conspicuous absence of the peak in the strong motion. Although we have taken the first step of establishing the presence of nonlinearity, it remains to define the physics of nonlinear response and to test the methodologies presently applied routinely in engineering practice. The inference of nonlinearity implies that care must be exercised in using sediment site data to study large earthquakes or predict strong ground motion. {copyright} 1998 American Geophysical Union

  4. 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.

  5. 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.

  6. Generation of a Near Infra-Red Guide Star Catalog for Thirty-Meter Telescope Observations

    NASA Astrophysics Data System (ADS)

    Subramanian, Smitha; Subramaniam, Annapurni; Simard, Luc; Gillies, Kim; Ramaprakash, A. N.; Anupama, G. C.; Stalin, C. S.; Ravindranath, Swara; Reddy, B. Eswar

    2013-06-01

    The requirements for the production of a near Infra-Red Guide Star Catalog (IRGSC) for Thirty Meter Telescope (TMT) observations are identified and presented. A methodology to compute the expected J band magnitude of stellar sources from their optical ( g, r, i) magnitudes is developed. The computed and observed J magnitudes of sources in three test fields are compared and the methodology developed is found to be satisfactory for the magnitude range, JVega = 16-22 mag. From this analysis, we found that for the production of final TMT IRGSC (with a limiting magnitude of JVega = 22 mag), we need g, r, i bands optical data which go up to i AB ~ 23 mag. Fine tuning of the methodology developed, such as using Spectral Energy Distribution (SED) template fitting for optimal classification of stars in the fainter end, incorporating spectral libraries in the model, to reduce the scatter, and modification of the existing colour-temperature relation to increase the source density are planned for the subsequent phase of this work.

  7. 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.

  8. TOWARD UNDERSTANDING THE ENVIRONMENT OF R MONOCEROTIS FROM HIGH-RESOLUTION NEAR-INFRARED POLARIMETRIC OBSERVATIONS

    SciTech Connect

    Jolin, M.-A.; Bastien, P.; Denni, F.; Lafreniere, D.; Doyon, R.; Voyer, P.

    2010-10-01

    High-resolution H-band imaging polarimetric observations of R Mon obtained at the Canada-France-Hawaii telescope are presented. These data show a centrosymmetric pattern with elongated intensity contours mostly due to the presence of the companion R Mon B. We also consider published R-band data, which show an extended right-angle conical reflection nebula with an offset in the optical peak. We study the circumstellar environment of R Mon with a radiative transfer Monte Carlo code. The best-fitting model obtained succeeds in reproducing the characteristics seen in the data in the two bands simultaneously. The model indicates the presence of relatively small astronomical silicate grains ranging from 0.04 {mu}m to 0.15 {mu}m distributed into three structures: a small disk, an inner envelope, and an outer envelope. The cavity is modeled by a conical structure with a constant low density and we include a 'throat' to produce the offset of the optical peak. Our model predicts a polarization reversal by 90{sup 0} between the R and H bands. Observations show that position angles parallel, perpendicular, and also at other angles to the disk can occur over time in the near-infrared.

  9. 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".

  10. Development and test of the Atmospheric Infrared Sounder (AIRS) for the NASA Earth Observing System (EOS)

    NASA Astrophysics Data System (ADS)

    Morse, Paul G.; Bates, Jerry C.; Miller, Christopher R.; Chahine, Moustafa T.; O'Callaghan, Fred; Aumann, Hartmut H.; Karnik, Avinash R.

    1999-12-01

    The Atmospheric Infrared Sounder (AIRS) has been developed for the NASA Earth Observing System (EOS) program for a scheduled launch on the EOS PM-1 spacecraft in December 2000. AIRS, working in concert with complementary microwave instrumentation on EOS PM-1, is designed to provide both new and more accurate data about the atmosphere, land and oceans for application to climate studies and weather prediction. Among the important parameters to be derived from AIRS observations are atmospheric temperature profiles with an average accuracy of 1 K in 1 kilometer (km) layers in the troposphere, humidity profiles to 10% accuracy and surface temperatures with an average accuracy of 0.5 K. The AIRS measurement technique is based on passive IR remote sensing using a precisely calibrated grating spectrometer operating in the 3.7 - 15.4 micrometer region. The instrument concept uses a passively cooled array spectrometer approach in combination with advanced state of the art focal plan and cryogenic refrigerator technology to achieve high performance in a practical long life configuration. The AIRS instrument has successfully completed a comprehensive performance verification program conducted at the Lockheed Martin IR Imaging Systems (LMIRIS) AIRS Test and Calibration Facility (ATCF), which was specially designed for precise spectroradiometric testing of space instrumentation. This paper provides a brief overview of the AIRS mission and instrument design, ATCF test capabilities, along with key results.

  11. 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.

  12. Multicolor Infrared Observations of SN 2006aj. I. The Supernova Associated with XRF 060218

    NASA Astrophysics Data System (ADS)

    Kocevski, Daniel; Modjaz, Maryam; Bloom, Joshua S.; Foley, Ryan; Starr, Daniel; Blake, Cullen H.; Falco, Emilio E.; Butler, Nathaniel R.; Skrutskie, Mike; Szentgyorgyi, Andrew

    2007-07-01

    We report simultaneous multicolor near-infrared (NIR) observations of the supernova associated with X-ray flash 060218 during the first 16 days after the high-energy event. We find that the light curve rises and peaks relatively fast compared to other Type Ic supernovae (SNe Ic), with the characteristic broad NIR peak seen in all three bands. We find that the rise profile before the peak is largely independent of NIR wavelength, each band appearing to transition into a plateau phase around day 10-13. Since the light curve is in the plateau phase when our observations end at day 16, we can only place limits on the peak absolute magnitudes, but we estimate that SN 2006aj is one of the lowest NIR luminosity X-ray flash/gamma-ray burst (XRF/GRB) associated SNe observed to date. The broad peaks observed in the JHKs bands point to a large increase in the NIR contribution of the total flux output from days 10-16. This evolution can be seen in the broad color and spectral energy distribution diagrams constructed using UBVRIJHKs monochromatic flux measurements for the first 16 days of the event. Ultimately, a 10 day rise time would make SN 2006aj an extremely fast rise SN Ic event, faster than SN 1998bw and SN 2003dh, which combined with its underluminous nature indicates a lower amount of 56Ni ejected by the progenitor compared to other XRF/GRB-SNe. Furthermore, the lack of significant color change during the rise portion of the burst points to little or no spectral evolution over the first 10 days of activity in the NIR.

  13. 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

  14. Deep Imaging Observations of the Lupus 3 Cloud: Dark Cloud Revealed as Infrared Reflection Nebula

    NASA Astrophysics Data System (ADS)

    Nakajima, Yasushi; Nagata, Tetsuya; Sato, Shuji; Nagayama, Takahiro; Nagashima, Chie; Kato, Daisuke; Kurita, Mikio; Kawai, Toshihide; Tamura, Motohide; Nakaya, Hidehiko; Sugitani, Koji

    2003-03-01

    We carried out deep imaging observations of the Lupus 3 dark cloud in near-infrared J, H, and Ks bands. An area of ~8'×8' was observed, which corresponds to a projected area of ~0.4×0.4 pc at the distance of the cloud, ~150 pc. Lupus 3 showed itself as a near-infrared nebula that has a surface brightness higher than the adjacent sky at all the three wavelengths. In a JHKs color composite image (blue, green, and red are assigned to J, H, and Ks, respectively), three dark red cores are surrounded by a blue halo. The surface brightness was measured with 5 σ limiting magnitudes of J=21.6, H=21.3, and Ks=20.6 mag arcsec-2. The appearance of the nebula depends on the wavelength. In the J band, dark cores are surrounded by a brighter halo, while in the Ks band, the dark cores of the J band are bright except for the central part of two of the cores. The appearance in the H band is intermediate between those of the J and Ks bands, having dark cores surrounded by local maxima of the surface brightness and decreased surface brightness farther out. The surface brightness is J=20.6, H=19.8, and Ks=19.4 mag arcsec-2 at the maximum in each band. Photometry of the point sources was done with 10 σ limiting magnitudes of J=20.1, H=18.8, and Ks=17.7. We constructed an extinction map of the background stars, using the H-K color of 1974 sources and the standard reddening law of Rieke & Lebofsky. The maximum value for the extinction is AV=47 mag. There are three local maxima of the extinction with AV>~30 mag, which we consider to be dense cores. Their positions agree with the cores identified with the surface brightness appearance. The surface brightness and its relationship with the extinction are understood in terms of scattering of starlight by dust. The values of the maximum surface brightness can be explained by scattering of starlight by dust in the cloud if we adopt a model of grain size distribution by Weingartner & Draine.

  15. 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

  16. Keck infrared observations of Saturn's main rings bracketing Earth's August 1995 ring plane crossing

    NASA Astrophysics Data System (ADS)

    Verbanac, Giuli; de Pater, Imke; Showalter, Mark R.; Lissauer, Jack J.

    2005-03-01

    We present results of near-infrared (2.26 μm) observations of Saturn's main rings taken with the W.M. Keck telescope during August 8-11, 1995, surrounding the time that Earth crossed Saturn's ring plane. These observations provide a unique opportunity to study the evolution of the ring brightness in detail, and by combining our data with Hubble Space Telescope (HST) results (Nicholson et al., 1996, Science 272, 453-616), we extend the 12-hour HST time span to several days around the time of ring plane crossing (RPX). In this paper, we focus on the temporal evolution of the brightness in Saturn's main rings. We examine both edge-on ring profiles and radial profiles obtained by "onion-peeling" the edge-on data. Before RPX, when the dark (unlit) face of the rings was observed, the inner C ring (including the Colombo gap), the Maxwell gap, Cassini Division and F ring region were very bright in transmitted light. After RPX, the main rings brighten rapidly, as expected. The profiles show east-west asymmetries both before and after RPX. Prior to RPX, the evolution in ring brightness of the Keck and HST data match one another quite well. The west side of the rings showed a nonlinear variation in brightness during the last hours before ring plane crossing, suggestive of clumping and longitudinal asymmetries in the F ring. Immediately after RPX, the east side of the rings brightened more rapidly than the west. A quantitative comparison of the Keck and HST data reveals that the rings were redder before RPX than after; we ascribe this difference to the enhanced multiple scattering of photons passing through to the unlit side of the rings.

  17. Feeding versus feedback in AGN from near-infrared IFU observations XI: NGC 2110

    NASA Astrophysics Data System (ADS)

    Diniz, Marlon R.; Riffel, Rogemar A.; Storchi-Bergmann, Thaisa; Winge, Claudia

    2015-10-01

    We present a two-dimensional mapping of the gas flux distributions, as well as of the gas and stellar kinematics in the inner 220 pc of the Seyfert galaxy NGC 2110, using K-band integral field spectroscopy obtained with the Gemini Near-infrared Integral Field Spectrograph at a spatial resolution of ≈24 pc and spectral resolution of ≈40 km s- 1. The H2 λ2.1218 μm emission extends over the whole field of view and is attributed to heating by X-rays from the AGN and/or by shocks, while the Brγ emission is restricted to a bipolar region extending along the south-east-north-west direction. The masses of the warm molecular gas and of the ionized gas are M_H_2≈ 1.4× 10^3 {M_{{⊙}}} and M_{H II}≈ 1.8× 10^6 {M_{{⊙}}}, respectively. The stellar kinematics present velocity dispersions reaching 250 km s-1 and a rotation pattern reaching an amplitude of 200 km s-1. The gas velocity fields present a similar rotation pattern but also additional components that we attribute to inflows and outflows most clearly observed in the molecular gas emission. The inflows are observed beyond the inner 70 pc and are associated with a spiral arm seen in blueshift to the north-east and another in redshift to the south-west. We have estimated a mass inflow rate in warm molecular gas of ≈4.6 × 10-4 M⊙ yr-1. Within the inner 70 pc, another kinematic component is observed in the H2 emission that can be interpreted as due to a bipolar nuclear outflow oriented along the east-west direction, with a mass outflow rate of ≈4.3 × 10-4 M⊙ yr-1 in warm H2.

  18. 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

  19. Thermal Model Calibration for Minor Planets Observed with Wide-field Infrared Survey Explorer/NEOWISE

    NASA Astrophysics Data System (ADS)

    Mainzer, A.; Grav, T.; Masiero, J.; Bauer, J.; Wright, E.; Cutri, R. M.; McMillan, R. S.; Cohen, M.; Ressler, M.; Eisenhardt, P.

    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 ~10% and ~20%, respectively. Additionally, visible albedos for the objects are computed and compared to the albedos at 3.4 μm and 4.6 μm, 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 NEATM model.

  20. 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.

  1. 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.

  2. 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.

  3. Thermal infrared observations and thermophysical characterization of the OSIRIS-REx target asteroid (101955) Bennu

    NASA Astrophysics Data System (ADS)

    Emery, J.; Fernandez, Y.; Kelley, M.; Warden, K.; Hergenrother, C.; Lauretta, D.; Drake, M.; Campins, H.; Ziffer, J.

    2014-07-01

    Near-Earth asteroids (NEAs) have garnered ever-increasing attention over the past few years due to the insights they offer into Solar System formation and evolution, the potential hazard they pose, and their accessibility for both robotic and human spaceflight missions. Among the NEAs, carbonaceous asteroids hold particular interest, because they may contain clues to how the Earth got its supplies of water and organic materials, and because none has yet been studied in detail by spacecraft. (101955) Bennu is special among the NEAs in that it will not only be visited by a spacecraft, but the OSIRIS-REx mission will also return a sample of Bennu's regolith to the Earth for detailed laboratory study. We present analysis of thermal infrared photometry and spectroscopy to test the hypotheses that Bennu is carbonaceous and that its surface is covered in fine-grained (sub-cm) regolith. The Spitzer Space Telescope observed Bennu in 2007, using the Infrared Spectrograph (IRS) to obtain spectra over the wavelength range of 5.2-38 μ m and images at 16 and 22 μ m at 10 different longitudes, as well as the Infrared Array Camera (IRAC) to image Bennu at 3.6, 4.5, 5.8, and 8.0 μ m, also at 10 different longitudes. Thermophysical analysis, assuming a spherical body with the known rotation period and spin-pole orientation, returns an effective diameter of 484±10 m, in agreement with the effective diameter calculated from the radar shape model at the orientation of the Spitzer observations (492±20 m, Nolan et al. 2013) and a visible geometric albedo of 0.046±0.005 (using H_{V}=20.51, Hergenrother et al. 2013). Including the radar shape model in the thermal analysis, and taking surface roughness into account, yields a disk-averaged thermal inertia of 310±70 J m^{-2}K^{-1}s^{-1/2}, which is significantly lower than that for several other NEAs of comparable size. There may be a small variation of thermal inertia with rotational phase (±60 J m^{-2}K^{-1}s^{-1/2}). The spectral

  4. Thermal infrared observations and thermophysical characterization of OSIRIS-REx target asteroid (101955) Bennu

    NASA Astrophysics Data System (ADS)

    Emery, J. P.; Fernández, Y. R.; Kelley, M. S. P.; Warden (nèe Crane), K. T.; Hergenrother, C.; Lauretta, D. S.; Drake, M. J.; Campins, H.; Ziffer, J.

    2014-05-01

    Near-Earth Asteroids (NEAs) have garnered ever increasing attention over the past few years due to the insights they offer into Solar System formation and evolution, the potential hazard they pose, and their accessibility for both robotic and human spaceflight missions. Among the NEAs, carbonaceous asteroids hold particular interest because they may contain clues to how the Earth got its supplies of water and organic materials, and because none has yet been studied in detail by spacecraft. (101955) Bennu is special among NEAs in that it will not only be visited by a spacecraft, but the OSIRIS-REx mission will also return a sample of Bennu’s regolith to Earth for detailed laboratory study. This paper presents analysis of thermal infrared photometry and spectroscopy that test the hypotheses that Bennu is carbonaceous and that its surface is covered in fine-grained (sub-cm) regolith. The Spitzer Space Telescope observed Bennu in 2007, using the Infrared Spectrograph (IRS) to obtain spectra over the wavelength range 5.2-38 μm and images at 16 and 22 μm at 10 different longitudes, as well as the Infrared Array Camera (IRAC) to image Bennu at 3.6, 4.5, 5.8, and 8.0 μm, also at 10 different longitudes. Thermophysical analysis, assuming a spherical body with the known rotation period and spin-pole orientation, returns an effective diameter of 484 ± 10 m, in agreement with the effective diameter calculated from the radar shape model at the orientation of the Spitzer observations (492 ± 20 m, Nolan, M.C., Magri, C., Howell, E.S., Benner, L.A.M., Giorgini, J.D., Hergenrother, C.W., Hudson, R.S., Lauretta, D.S., Margo, J.-L., Ostro, S.J., Scheeres, D.J. [2013]. Icarus 226, 629-640) and a visible geometric albedo of 0.046 ± 0.005 (using Hv = 20.51, Hergenrother, C.W. et al. [2013]. Icarus 226, 663-670). Including the radar shape model in the thermal analysis, and taking surface roughness into account, yields a disk-averaged thermal inertia of 310 ± 70 J m-2 K-1 s-1

  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. Radio and infrared observations of OH/IR stars at the tangential point and near the galactic center

    NASA Technical Reports Server (NTRS)

    Baud, B.; Sargent, A. I.; Werner, M. W.; Bentley, A. F.

    1985-01-01

    Unambiguous infrared identifications of a sample of OH/IR stars in the galactic disk and in the vicinity of the galactic center are presented. Simultaneous OH and broadband infrared photometric measurements are used to derive quantitative relations between the infrared and OH fluxes and the properties of the circumstellar shells, providing observational evidence that these stars represent an evolutionary sequence of increasing mass loss rate. These relations are used to explain the observed time variations of the silicate absorption feature with changing bolometric luminosity in OH/IR stars. It appears that the ratio of the OH flux to the number of pump photons is not constant, but is also a function of the mass loss rate.

  7. 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

  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. 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.

  11. 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.

  12. 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.

  13. SMARTS Optical and Near-Infrared Observations of Fermi LAT Blazars

    NASA Astrophysics Data System (ADS)

    Buxton, Michelle; Isler, J.; Urry, C. M.; Hasan, I.; MacPherson, E.; Bailyn, C. D.; Coppi, P. S.; Gamma-ray Space Telescope, Fermi

    2014-01-01

    Since 2008, we have been monitoring southern-hemisphere blazars at optical and near-infrared (OIR) wavelengths using the SMARTS 1.3m+ANDICAM instrument. Our targets are observed simultaneously with the Fermi Gamma-ray telescope providing us with an opportunity to probe the relative contribution of the thermal and non-thermal emission to the broad-band spectral energy distribution. In this poster we present our results which include OIR light curves that, in some cases, show ‘orphan’ flares in OIR fluxes that are not present in gamma-rays. In addition we see evidence for intra-night variability in some blazars. Discrete correlation functions of simultaneous gamma-ray and OIR fluxes suggest there is no lag or lead time between OIR and gamma-ray fluxes during some flares. Finally, color-magnitude diagrams of some blazars show clear changes in color over flares allowing us to study the evolution of accretion disk vs. jet emission during flaring events.

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. Visible/near-infrared spectrogoniometric observations and modeling of dust-coated rocks

    USGS Publications Warehouse

    Johnson, J. R.; Grundy, W.M.; Shepard, M.K.

    2004-01-01

    Interpretations of visible/near-infrared reflectance spectra of Mars are often complicated by the effects of dust coatings that obscure the underlying materials of interest. The ability to separate the spectral reflectance signatures of coatings and substrates requires an understanding of how their individual and combined reflectance properties vary with phase angle. Toward this end, laboratory multispectral observations of rocks coated with different amounts of Mars analog dust were acquired under variable illumination and viewing geometries using the Bloomsburg University Goniometer (BUG). These bidirectional reflectance distribution function (BRDF) data were fit with a two-layer radiative transfer model, which replicated BUG observations of dust-coated basaltic andesite substrates relatively well. Derived single scattering albedo and phase function parameters for the dust were useful in testing the model's ability to derive the spectrum of a "blind" substrate (unknown to the modeler) coated with dust. Subsequent tests were run using subsets of the BUG data restricted by goniometric or coating thickness coverage. Using the entire data set provided the best constraints on model parameters, although some reductions in goniometric coverage could be tolerated without substantial degradation. Predictably, the most thinly coated samples provided the best information on the substrate, whereas the thickest coatings best replicated the dust. Dust zenith optical thickness values ???0.6-0.8 best constrain the substrate and coating simultaneously, particularly for large ranges of incidence or emission angles. The lack of sufficient angles can be offset by having a greater number and range of coatings thicknesses. Given few angles and thicknesses, few constraints can be placed concurrently on the spectral properties of the coating and substrate. ?? 2004 Elsevier Inc. All rights reserved.

  1. 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.

    2016-10-01

    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 timescale for disc growth, during which the disc is being actively fed by mass injection episodes, is shorter than the timescale 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.

  2. 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 detection of improvised explosive devices (IED's), Raman spectroscopy and microscopy for life/physical science applications, and semiconductor product defect detection.

  3. 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.

  4. Europa's opposition surge in the near-infrared: interpreting disk-integrated observations by Cassini VIMS

    NASA Astrophysics Data System (ADS)

    Simonelli, Damon P.; Buratti, Bonnie J.

    2004-11-01

    Near-infrared observations of Europa's disk-integrated opposition surge by Cassini VIMS, first published in Fig. 4 of Brown et al. (2003, Icarus, 164, 461), have now been modeled with the commonly used Hapke photometric function. The VIMS data set emphasizes observations at 16 solar phase angles from 0.4° to 0.6°—the first time the <1° phase "heart" of Europa's opposition surge has been observed this well in the near-IR. This data set also provides a unique opportunity to examine how the surge is affected by changes in wavelength and albedo: at VIMS wavelengths of 0.91, 1.73, and 2.25 μm, the geometric albedo of Europa is 0.81, 0.33, and 0.18, respectively. Despite this factor-of-four albedo range, however, the slope of Europa's phase curve at <1° phase is similar at all three wavelengths (to within the error bars) and this common slope is similar to the phase coefficient seen in visible-light observations of Europa. The two components of the opposition surge—involving different models of the physical cause of the surge—are the Shadow Hiding Opposition Effect (SHOE) and the Coherent Backscatter Opposition Effect (CBOE). Because of sparse VIMS phase coverage, it is not possible to constrain all the surge parameters at once in a Hapke function that has both SHOE and CBOE; accordingly, we performed separate Hapke fits for SHOE-only and CBOE-only surges. At 2.25 μm, where VIMS data are somewhat noisy, both types of surges can mimic the slope of the VIMS phase curve at <1° phase. At 0.91 and 1.73 μm, however—where VIMS data are "cleaner"—CBOE does a noticeably poorer job than SHOE of matching the VIMS phase coefficient at <1° phase; in particular, the best CBOE fit insists on having a steeper phase-curve slope than the data. This discrepancy suggests that Europa's near-IR opposition surge cannot be explained by CBOE alone and must have a significant SHOE component, even at wavelengths where Europa is bright.

  5. Support for joint infrared and Copernicus X-Ray observations of Cygnus X-3

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Simultaneous X-ray and infrared measurements were carried out of the flares from Cygnus X-3 from the Copernicus spacecraft observatory. The detectors, InSb, were arranged so that 1.65 and 2.2 micrometer broadbend photometry was performed through a common diaphragm. The measurements were used to determine the energy distribution during a flare and thus learn about the infrared spectrum and its changes during the flare.

  6. 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

    2015-01-01

    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.

  7. 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

    2015-01-01

    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

  8. 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.

  9. Observation of finite-wavelength screening in high-energy-density matter

    DOE PAGES

    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.; et al

    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

  10. 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

  11. SPITZER OBSERVATIONS OF PASSIVE AND STAR-FORMING EARLY-TYPE GALAXIES: AN INFRARED COLOR-COLOR SEQUENCE

    SciTech Connect

    Temi, Pasquale

    2009-12-20

    We describe the infrared properties of a large sample of early-type galaxies, comparing data from the Spitzer archive with Ks-band emission from the Two Micron All Sky Survey. While most representations of this data result in correlations with large scatter, we find a remarkably tight relation among colors formed by ratios of luminosities in Spitzer-Multiband Imaging Photometer bands (24, 70, and 160 mum) and the Ks band. Remarkably, this correlation among E and S0 galaxies follows that of nearby normal galaxies of all morphological types. In particular, the tight infrared color-color correlation for S0 galaxies alone follows that of the entire Hubble sequence of normal galaxies, roughly in order of galaxy type from ellipticals to spirals to irregulars. The specific star formation rate (SFR) of S0 galaxies estimated from the 24 mum luminosity increases with decreasing K-band luminosity (or stellar mass) from essentially zero, as with most massive ellipticals, to rates typical of irregular galaxies. Moreover, the luminosities of the many infrared-luminous S0 galaxies can significantly exceed those of the most luminous (presumably post-merger) E galaxies. SFRs in the most infrared-luminous S0 galaxies approach 1-10 solar masses per year. Consistently, with this picture we find that while most early-type galaxies populate an infrared red sequence, about 24% of the objects (mostly S0s) are in an infrared blue cloud together with late-type galaxies. For those early-type galaxies also observed at radio frequencies, we find that the far-infrared luminosities correlate with the mass of neutral and molecular hydrogen, but the scatter is large. This scatter suggests that the star formation may be intermittent or that similar S0 galaxies with cold gaseous disks of nearly equal mass can have varying radial column density distributions that alter the local and global SFRs.

  12. Toward the characterization of upper tropospheric clouds using Atmospheric Infrared Sounder and Microwave Limb Sounder observations

    NASA Astrophysics Data System (ADS)

    Kahn, Brian H.; Eldering, Annmarie; Braverman, Amy J.; Fetzer, Eric J.; Jiang, Jonathan H.; Fishbein, Evan; Wu, Dong L.

    2007-03-01

    We estimate the accuracy of cloud top altitude (Z) retrievals from the Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit (AMSU) observing suite (ZA) on board the Earth Observing System Aqua platform. We compare ZA with coincident measurements of Z derived from the micropulse lidar and millimeter wave cloud radar at the Atmospheric Radiation Measurement (ARM) program sites of Nauru and Manus islands (ZARM) and the inferred Z from vertically resolved Microwave Limb Sounder (MLS) ice water content (IWC) retrievals. The mean difference in ZA minus ZARM plus or minus one standard deviation ranges from -2.2 to 1.6 km ± 1.0 to 4.2 km for all cases of AIRS effective cloud fraction (fA) > 0.15 at Manus Island using the cloud radar only. The range of mean values results from using different approaches to determine ZARM, day/night differences, and the magnitude of fA; the variation about the mean decreases for increasing values of fA. Analysis of ZARM from the micropulse lidar at Nauru Island for cases restricted to 0.05 ≤ fA ≤ 0.15 indicates a statistically significant improvement in ZA - ZARM over the cloud radar-derived values at Manus Island. In these cases the ZA - ZARM difference is -1.1 to 2.1 km ± 3.0 to 4.5 km. These results imply that the operational ZA is quantitatively useful for constraining cirrus altitude despite the nominal 45 km horizontal resolution. Mean differences of cloud top pressure (PCLD) inferred from coincident AIRS and MLS ice water content (IWC) retrievals depend upon the method of defining AIRS PCLD (as with the ARM comparisons) over the MLS spatial scale, the peak altitude and maximum value of MLS IWC, and fA. AIRS and MLS yield similar vertical frequency distributions when comparisons are limited to fA > 0.1 and IWC > 1.0 mg m-3. Therefore the agreement depends upon the opacity of the cloud, with decreased agreement for optically tenuous clouds. Further, the mean difference and standard deviation of AIRS and MLS

  13. Physical and chemical structure of the IC 63 nebula. 1: Millimeter and far-infrared observations

    NASA Technical Reports Server (NTRS)

    Jansen, David J.; Van Dishoeck, Ewine F.; Black, John H.

    1994-01-01

    We present results of a (sub)millimeter and far-infrared study of the reflection/emission nebula IC 63, located close to the BO.5p star gamma Cas. The source has been mapped in the (12)CO 2 - 1 and 3 - 2, (13)CO 2 - 1, and CS 2 - 1 lines and shows a small molecular cloud less than 1'x 2' in extent, which coincides with the brightest optical nebulosity and IRAS 100 micrometer emission. IC 63 is therefore an excellent example of a nearby (d approximately = 230 pc), edge-on photon-dominated region (PDR). Various other molecules have been observed at the peak position through their rotational transitions, in order to probe the physical parameters and to derive abundances. The measured CO, HCO(+) HCN, CS and H2CO line ratios suggest that the cloud is warm, T approximately = 50 K, and dense, n (H2) approximately = 5 x 10(exp 4)/cu cm. Excitation of molecules by electrons may play a significant role in this PDR. On the basis of these physical conditions, column densities have been determined from the observed line strengths. Several different methods are discussed to constrain the H2 column density, including the use of measured submillimeter continuum fluxes. The resulting abundances of species such as CN and CS are similar to those found in cold, dark clouds like TMC-1 and L134N. However, the abundances of other simple molecules such as HNC, HCO(+) and possibly C2H are lower by factors of at least three, probably because of the enhanced photodissociation rates at a distance of 1.3 pc from a B star. Surprisingly, only the abundance of the H2S molecule appears enhanced. More complex, volatile molecules such as CH3OH CH3CN and HNCO, and the sulfur-oxides SO and SO2 have not been found in this cloud. Limited observations of molecules in the reflection nebulea NGC 2023 are presented as well, and the resulting molecular abundances are compared with those found for IC 63.

  14. A New 350 GHz Heterodyne Array Receiver (HARP) and Observations of Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Leech, Jamie

    2002-08-01

    injection system is assessed experimentally, and is shown to be capable of delivering LO power to two prototype mixers. When the HARP receiver is commissioned on the JCMT, one potential astronomical application will be the spectroscopic observations of J=3 → 2 rotational transitions of CO in external galaxies, which occur in regions of dense molecular hydrogen gas. Observations of a sample of luminous infrared galaxies (LIGs), made with the current single element 350 GHz receiver on the JCMT, are presented. High infrared luminosity in galaxies is often triggered by galactic interactions, and the sample studied here is chosen to include LIGs with a variety of component nuclear separations. The CO(3-2) measurements allow important constraints to be placed on the excitation conditions of the molecular gas in LIGs, hence facilitating a greater understanding of the evolution of the molecular gas component, and star formation activity, as galactic merging progresses.

  15. Thermal and near infrared sensor for carbon observation Fourier-transform spectrometer on the Greenhouse Gases Observing Satellite for greenhouse gases monitoring.

    PubMed

    Kuze, Akihiko; Suto, Hiroshi; Nakajima, Masakatsu; Hamazaki, Takashi

    2009-12-10

    The Greenhouse Gases Observing Satellite (GOSAT) monitors carbon dioxide (CO(2)) and methane (CH(4)) globally from space using two instruments. The Thermal and Near Infrared Sensor for Carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) detects gas absorption spectra of the solar short wave infrared (SWIR) reflected on the Earth's surface as well as of the thermal infrared radiated from the ground and the atmosphere. TANSO-FTS is capable of detecting three narrow bands (0.76, 1.6, and 2.0 microm) and a wide band (5.5-14.3 microm) with 0.2 cm(-1) spectral resolution (interval). The TANSO Cloud and Aerosol Imager (TANSO-CAI) is an ultraviolet (UV), visible, near infrared, and SWIR radiometer designed to detect cloud and aerosol interference and to provide the data for their correction. GOSAT is placed in a sun-synchronous orbit 666 km at 13:00 local time, with an inclination angle of 98 degrees . A brief overview of the GOSAT project, scientific requirements, instrument designs, hardware performance, on-orbit operation, and data processing is provided. PMID:20011012

  16. Experimental Fault Diagnosis in Systems Containing Finite Elements of Plate of Kirchoff by Using State Observers Methodology

    NASA Astrophysics Data System (ADS)

    Alegre, D. M.; Koroishi, E. H.; Melo, G. P.

    2015-07-01

    This paper presents a methodology for detection and localization of faults by using state observers. State Observers can rebuild the states not measured or values from points of difficult access in the system. So faults can be detected in these points without the knowledge of its measures, and can be track by the reconstructions of their states. In this paper this methodology will be applied in a system which represents a simplified model of a vehicle. In this model the chassis of the car was represented by a flat plate, which was divided in finite elements of plate (plate of Kirchoff), in addition, was considered the car suspension (springs and dampers). A test rig was built and the developed methodology was used to detect and locate faults on this system. In analyses done, the idea is to use a system with a specific fault, and then use the state observers to locate it, checking on a quantitative variation of the parameter of the system which caused this crash. For the computational simulations the software MATLAB was used.

  17. Hubble Space Telescope WFC3 Early Release Science: Emission-line Galaxies from Infrared Grism Observations

    NASA Astrophysics Data System (ADS)

    Straughn, Amber N.; Kuntschner, Harald; Kümmel, Martin; Walsh, Jeremy R.; Cohen, Seth H.; Gardner, Jonathan P.; Windhorst, Rogier A.; O'Connell, Robert W.; Pirzkal, Norbert; Meurer, Gerhardt; McCarthy, Patrick J.; Hathi, Nimish P.; Malhotra, Sangeeta; Rhoads, James; Balick, Bruce; Bond, Howard E.; Calzetti, Daniela; Disney, Michael J.; Dopita, Michael A.; Frogel, Jay A.; Hall, Donald N. B.; Holtzman, Jon A.; Kimble, Randy A.; Mutchler, Max; Paresce, Francesco; Saha, Abhijit; Silk, Joseph I.; Trauger, John T.; Walker, Alistair R.; Whitmore, Bradley C.; Young, Erick T.; Xu, Chun

    2011-01-01

    We present grism spectra of emission-line galaxies (ELGs) from 0.6 to 1.6 μm from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope. These new infrared grism data augment previous optical Advanced Camera for Surveys G800L 0.6-0.95 μm grism data in GOODS-South from the PEARS program, extending the wavelength coverage well past the G800L red cutoff. The Early Release Science (ERS) grism field was observed at a depth of two orbits per grism, yielding spectra of hundreds of faint objects, a subset of which is presented here. ELGs are studied via the Hα, [O III], and [O II] emission lines detected in the redshift ranges 0.2 <~ z <~ 1.4, 1.2 <~ z <~ 2.2, and 2.0 <~ z <~ 3.3, respectively, in the G102 (0.8-1.1 μm R ~= 210) and G141 (1.1-1.6 μm R ~= 130) grisms. The higher spectral resolution afforded by the WFC3 grisms also reveals emission lines not detectable with the G800L grism (e.g., [S II] and [S III] lines). From these relatively shallow observations, line luminosities, star formation rates, and grism spectroscopic redshifts are determined for a total of 48 ELGs to m AB(F098M) ~= 25 mag. Seventeen GOODS-South galaxies that previously only had photometric redshifts now have new grism-spectroscopic redshifts, in some cases with large corrections to the photometric redshifts (Δz ~= 0.3-0.5). Additionally, one galaxy had no previously measured redshift but now has a secure grism-spectroscopic redshift, for a total of 18 new GOODS-South spectroscopic redshifts. The faintest source in our sample has a magnitude m AB(F098M)= 26.9 mag. The ERS grism data also reflect the expected trend of lower specific star formation rates for the highest mass galaxies in the sample as a function of redshift, consistent with downsizing and discovered previously from large surveys. These results demonstrate the remarkable efficiency and capability of the WFC3 NIR grisms for measuring galaxy properties to faint magnitudes and redshifts to z >~ 2.

  18. Infrared Spectroscopy of 7-AZAINDOLE Tautomeric Dimer: Observation of the nd Stretch

    NASA Astrophysics Data System (ADS)

    Ishikawa, Haruki; Nakano, Takumi; Yabuguchi, Hiroki; Fujihara, Akimasa; Fuke, Kiyokazu

    2010-06-01

    7-azaindole (7-AI) dimer is a very attractive species as a model system of nucleic-acid base pair. The 7-AI dimer is known to exhibit the excited-state double proton transfer (DPT) reaction. The tautomeric dimer produced in the DPT reaction goes back to normal form in the electronic ground state, in solution. In general, the proton-transfer reaction is a fundamental and an important elementary reaction in various chemical and biological systems. However, the ground-state reverse DPT reaction is not thoroughly studied, so far. Thus, we carry out infrared (IR) spectroscopy of the jet-cooled 7-AI tautomeric dimer. In our previous study, we measured IR spectra of the tautomeric dimer and its deuterated species in the NH stretch region and discussed the vibrational dynamic based on the band profiles. In order to obtain more precise information about the deuteration effect, we have observed the ND stretch bands of the deuterated dimers in the present study. The deuteration of the NH hydrogen provides three deuterated species, such as the NH-NH, NH-ND, and ND-ND dimers. The NH stretch band of the NH-NH dimer appears at 2680 cm-1. It exhibits a less-structured and broad profile whose width is ˜245 cm-1. On the contrary, the NH-ND dimer exhibits a narrower NH stretch band width. This difference is attributed to a change in the vibrational energy flow between the two monomer units in the dimer. In the present study, we have succeeded in measuring the ND stretch bands of the NH-ND and the ND-ND dimers. The ND stretch band of the ND-ND dimer appears at 2120 cm-1 and its width is found to be ˜90 cm-1, whereas that of the NH-ND dimer is red-shifted and exhibits rather narrow width. Based on these observations, the single-deuteration effect on the vibrational dynamics and its relation to the DPT reaction is discussed in the paper. H. Ishikawa, H. Yabuguchi, Y. Yamada, A. Fujihara, and K. Fuke, J. Phys. Chem. A, in press.

  19. CO2 Dimer: Four Intermolecular Modes Observed via Infrared Combination Bands

    NASA Astrophysics Data System (ADS)

    Norooz Oliaee, Jalal; Dehghany, Mehdi; Rezaei, Mojtaba; McKellar, Bob; Moazzen-Ahmadi, Nasser

    2016-06-01

    Study of the carbon dioxide dimer has a long history, but there is only one previous observation of an intermolecular vibration [1]. Here we analyze four new combination bands of (CO2)2 in the CO2 νb{3} region (˜2350 wn), observed using tunable infrared lasers and a pulsed slit-jet supersonic expansion. The previous combination band at 2382.2 wn was simple to assign [1]. A much more complicated band (˜2370 wn) turns out to involve two upper states, one at 2369.0 wn (Bu symmetry), and the other at 2370.0 wn (Au). The spectrum can be nicely fit by including the Coriolis interactions between these states. Another complicated band around 2443 wn also involves two nearby upper states which are highly perturbed in so-far unexplained ways (possibly related to tunneling shifts). With the help of new ab initio calculations [2], we assign the results as follows. The 2369.0 wn band is the combination of the forbidden Ag intramolecular fundamental (probably [1] at about 2346.76 wn) and the intermolecular geared bend (Bu). The 2370.0 wn band is the combination of the same Ag fundamental and the intermolecular torsion (Au). This gives about 22.3 and 23.2 wn for the geared bend and torsion. The previous 2382.2 wn band [1] is the allowed Bu fundamental (2350.771 wn) plus two quanta of the geared bend (Bu), giving 31.509 wn for this overtone. The highly perturbed 2442.7 wn band is the Bu fundamental plus the antigeared bend (Ag), giving about 91.9 wn for the antigeared bend. Finally, the perturbed 2442.1 wn band is due to an unknown combination of modes which gains intensity from the antigeared bend by a Fermi-type interaction. Calculated values [2] are: 20.64 (geared bend), 24.44 (torsion), 32.34 (geared bend overtone), and 92.30 wn (antigeared bend), in good agreement with experiment. \\vskip 0.2 truecm [1] M. Dehghany, A.R.W. McKellar, Mahin Afshari, and N. Moazzen-Ahmadi, Mol. Phys. 108, 2195 (2010). [2] X.-G. Wang, T. Carrington, Jr., and R. Dawes, private communication.

  20. Imaging magnetographs for high-resolution solar observations in the visible and near-infrared wavelength region

    NASA Astrophysics Data System (ADS)

    Denker, C.; Didkovsky, L.; Ma, J.; Shumko, S.; Varsik, J.; Wang, J.; Wang, H.; Goode, P. R.

    The Coudé feed of the vacuum telescope (aperture D=65 cm) at the Big Bear Solar Observatory (BBSO) is currently completely remodelled to accommodate a correlation tracker and a high-order Adaptive Optics (AO) system. The AO system serves two imaging magnetograph systems located at a new optical laboratory on the observatory's 2nd floor. The InfraRed Imaging Magnetograph (IRIM) is an innovative magnetograph system for near-infrared (NIR) observations in the wavelength region from 1.0 mu m to 1.6 mu m. The Visible-light Imaging Magnetograph (VIM) is basically a twin of IRIM for observations in the wavelength range from 550 nm to 700 nm. Both instruments were designed for high spatial and high temporal observations of the solar photosphere and chromosphere. Real-time data processing is an integral part of the instruments and will enhance BBSO's capabilities in monitoring solar activity and predicting and forecasting space weather.

  1. Thermal infrared pushbroom imagery acquisition and processing. [of NASA's Advanced Land Observing System

    NASA Technical Reports Server (NTRS)

    Brown, T. J.; Corbett, F. J.; Spera, T. J.; Andrada, T.

    1982-01-01

    A 9-element focal plane detector array and signal processing electronics was developed and delivered in December 1977. It was integrated into a thermal infrared imaging system using LSI microprocessor image processing and CRT display. After three years of laboratory operation, the focal plane has demonstrated high reliability and performance. On the basis of the 9-channel breadboard, the 90-element Aircraft Pushbroom IR/CCD Focal Plane Development Program was funded in October 1977. A follow-on program was awarded in July 1979, for the construction of a field test instrument and image processing facility. The objective of this project was to demonstrate thermal infrared pushbroom hard-copy imagery. It is pointed out that the successful development of the 9-element and 90-element thermal infrared hybrid imaging systems using photoconductive (Hg,Cd)Te has verified the operational concept of 8 to 14 micrometer pushbroom scanners.

  2. First Science Observations with SOFIA/FORCAST: The FORCAST Mid-infrared Camera

    NASA Astrophysics Data System (ADS)

    Herter, T. L.; Adams, J. D.; De Buizer, J. M.; Gull, G. E.; Schoenwald, J.; Henderson, C. P.; Keller, L. D.; Nikola, T.; Stacey, G.; Vacca, W. D.

    2012-04-01

    The Stratospheric Observatory For Infrared Astronomy (SOFIA) completed its first light flight in May of 2010 using the facility mid-infrared instrument FORCAST. Since then, FORCAST has successfully completed 13 science flights on SOFIA. In this Letter, we describe the design, operation, and performance of FORCAST as it relates to the initial three Short Science flights. FORCAST was able to achieve near-diffraction-limited images for λ > 30 μm allowing unique science results from the start with SOFIA. We also describe ongoing and future modifications that will improve overall capabilities and performance of FORCAST.

  3. FIRST SCIENCE OBSERVATIONS WITH SOFIA/FORCAST: THE FORCAST MID-INFRARED CAMERA

    SciTech Connect

    Herter, T. L.; Adams, J. D.; Gull, G. E.; Schoenwald, J.; Henderson, C. P.; Nikola, T.; Stacey, G.; De Buizer, J. M.; Vacca, W. D.; Keller, L. D.

    2012-04-20

    The Stratospheric Observatory For Infrared Astronomy (SOFIA) completed its first light flight in May of 2010 using the facility mid-infrared instrument FORCAST. Since then, FORCAST has successfully completed 13 science flights on SOFIA. In this Letter, we describe the design, operation, and performance of FORCAST as it relates to the initial three Short Science flights. FORCAST was able to achieve near-diffraction-limited images for {lambda} > 30 {mu}m allowing unique science results from the start with SOFIA. We also describe ongoing and future modifications that will improve overall capabilities and performance of FORCAST.

  4. Late-time Near-infrared Observations of SN 2005df

    NASA Astrophysics Data System (ADS)

    Diamond, Tiara R.; Hoeflich, Peter; Gerardy, Christopher L.

    2015-06-01

    We present late-time near-infrared (NIR) spectral evolution, at 200-400 days, for the Type Ia supernova SN 2005df. The spectra show numerous strong emission features of [Co ii], [Co iii], and [Fe ii] throughout the 0.8-1.8 μm region. As the spectrum ages, the cobalt features fade as would be expected from the decay of 56Co to 56Fe. We show that the strong and isolated [Fe ii] emission line at 1.644 μ {m} provides a unique tool to analyze NIR spectra of SNe Ia. Normalization of spectra to this line allows the separation of features produced by stable versus unstable isotopes of iron group elements. We develop a new method of determining the initial central density, {ρ }c, and the magnetic field, B, of the white dwarf (WD) using the width of the 1.644 μ {m} line. The line width (LW) is sensitive because of electron capture in the early stages of burning, which increases as a function of density. The sensitivity of the LW to B increases with time, and the effects of the magnetic field shift toward later times with decreasing {ρ }c. Through comparison with spherical models, the initial central density for SN 2005df is measured as {ρ }c=0.9(+/- 0.2)× {10}9 {g} {{cm}}-3, which corresponds to a WD close to the Chandrasekhar mass, with {M}{WD}=1.31(+/- 0.03) {M}⊙ and systematic error less than 0.04 {M}⊙. This error estimate is based on spherical models. We discuss the potential uncertainties due to multi-dimensional effects, mixing, and rotation. The latter two effects would increase the estimate of the WD mass. Within {M}{Ch} explosions, however, the central density found for SN 2005df is very low for a H-accretor, possibly suggesting a helium star companion or a tidally disrupted WD companion. As an alternative, we suggest mixing of the central region. We find some support for high initial magnetic fields of strength {10}6 {G} for SN 2005df, however, 0 {G} cannot be ruled out because of noise in the spectra combined with low {ρ }c. We discuss our findings in

  5. VERY LARGE ARRAY OBSERVATIONS OF THE INFRARED DARK CLOUD G19.30+0.07

    SciTech Connect

    Devine, K. E.; Churchwell, E.; Chandler, C. J.; Borg, K. J.; Brogan, C.; Indebetouw, R.; Shirley, Y.

    2011-05-20

    We present Very Large Array observations of ammonia (NH{sub 3}) (1,1), (2,2), and dicarbon sulfide (CCS) (2{sub 1}-1{sub 0}) emission toward the infrared dark cloud (IRDC) G19.30+0.07 at {approx}22 GHz. The NH{sub 3} emission closely follows the 8 {mu}m extinction. The NH{sub 3} (1,1) and (2,2) lines provide diagnostics of the temperature and density structure within the IRDC, with typical rotation temperatures of {approx}10-20 K and NH{sub 3} column densities of {approx}10{sup 15} cm{sup -2}. The estimated total mass of G19.30+0.07 is {approx}1130 M{sub sun}. The cloud comprises four compact NH{sub 3} clumps of mass {approx}30-160 M{sub sun}. Two coincide with 24 {mu}m emission, indicating heating by protostars, and show evidence of outflow in the NH{sub 3} emission. We report a water maser associated with a third clump; the fourth clump is apparently starless. A non-detection of 8.4 GHz emission suggests that the IRDC contains no bright H II regions and places a limit on the spectral type of an embedded zero-age main-sequence star to early-B or later. From the NH{sub 3} emission, we find that G19.30+0.07 is composed of three distinct velocity components or 'subclouds'. One velocity component contains the two 24 {mu}m sources and the starless clump, another contains the clump with the water maser, while the third velocity component is diffuse, with no significant high-density peaks. The spatial distribution of NH{sub 3} and CCS emission from G19.30+0.07 is highly anti-correlated, with the NH{sub 3} predominantly in the high-density clumps and the CCS tracing lower-density envelopes around those clumps. This spatial distribution is consistent with theories of evolution for chemically young low-mass cores, in which CCS has not yet been processed to other species and/or depleted in high-density regions.

  6. Observation of angular effects on thermal infrared emissivity derived with the MODTES algorithm and MODIS data

    NASA Astrophysics Data System (ADS)

    García-Santos, Vicente; Niclòs, Raquel; Coll, César; Valor, Enric; Caselles, Vicente

    2015-04-01

    The MOD21 Land Surface Temperature and Emissivity (LST&E) product will be included in forthcoming MODIS Collection 6. Surface temperature and emissivities for thermal infrared (TIR) bands 29 (8.55 μm), 31 (11 μm) and 32 (12 μm) will be retrieved using the ASTER TES method adapted to MODIS at-sensor spectral radiances, previously corrected with the Water Vapor Scaling method (MODTES algorithm). LSE of most natural surfaces changes with soil moisture content, type of surface cover, surface roughness or sensor viewing geometry. The present study addresses the observation of anisotropy effects on LSE of bare soils using MODIS data and a processor simulator of the MOD21 product, since it is not available yet. Two highly homogeneous and quasi-invariant desert sites were selected to carry out the present study. The first one is the White Sands National Monument, located in Tularosa Valley (South-central New Mexico, USA), which is a dune system desert at 1216 m above sea level, with an area of 704 km2 and a maximum dune height of 10 m. The grain size is considered fine sand and the major mineralogy component is gypsum. The second site selected was the Great Sands National Park, located in the San Luis Valley (Colorado, USA). Great Sands is also a sand dune system desert, created from quartz and volcanic fragments derived from Santa Fe and Alamosa formations. The major mineral is quartz, with minor traces of potassium and feldspar. The grain size of the sand is medium to coarse according to the X-Ray Diffraction measurements. Great Sands covers an area of 104 km2 at 2560 m above sea level and the maximum dune height is 230 m. The obtained LSEs and their dependence on azimuth and zenith viewing angles were analyzed, based on series of MODIS scenes from 2010 to 2013. MODTES nadir and off-nadir LSEs showed a good agreement with laboratory emissivity measurements. Results show that band 29 LSE decreases with the zenithal angle up to 0.041 from its nadir value, while LSEs for

  7. Clouds across the Arctic: A spatial perspective uniting surface observations of downwelling infrared radiation, reanalyses and education

    NASA Astrophysics Data System (ADS)

    Cox, Christopher J.

    The polar regions serve an important role in the Earth's energy balance by acting as a heat sink for the global climate system. In the Arctic, a complex distribution of continental and oceanic features support large spatial variability in environmental parameters important for climate. Additionally, feedbacks that are unique to the cryosphere cause the region to be very sensitive to climate perturbations. Environmental changes are being observed, including increasing temperatures, reductions in sea ice extent and thickness, melting permafrost, changing atmospheric circulation patterns and changing cloud properties, which may be signaling a shift in climate. Despite these changes, the Arctic remains an understudied region, including with respect to the atmosphere and clouds. A better understanding of cloud properties and their geographical variability is needed to better understand observed changes and to forecast the future state of the system, to support adaptation and mitigation strategies, and understand how Arctic change impacts other regions of the globe. Surface-based observations of the atmosphere are critical measurements in this effort because they are high quality and have high temporal resolution, but there are few atmospheric observatories in the Arctic and the period of record is short. Reanalyses combine assimilated observations with models to fill in spatial and temporal data gaps, and also provide additional model-derived parameters. Reanalyses are spatially comprehensive, but are limited by large uncertainties and biases, in particular with respect to derived parameters. Infrared radiation is a large component of the surface energy budget. Infrared emission from clouds is closely tied to cloud properties, so measurements of the infrared spectrum can be used to retrieve information about clouds and can also be used to investigate the influence clouds have on the surface radiation balance. In this dissertation, spectral infrared radiances and other

  8. BRIGHTNESS AND FLUCTUATION OF THE MID-INFRARED SKY FROM AKARI OBSERVATIONS TOWARD THE NORTH ECLIPTIC POLE

    SciTech Connect

    Pyo, Jeonghyun; Jeong, Woong-Seob; Matsumoto, Toshio; Matsuura, Shuji

    2012-12-01

    We present the smoothness of the mid-infrared sky from observations by the Japanese infrared astronomical satellite AKARI. AKARI monitored the north ecliptic pole (NEP) during its cold phase with nine wave bands covering from 2.4 to 24 {mu}m, out of which six mid-infrared bands were used in this study. We applied power-spectrum analysis to the images in order to search for the fluctuation of the sky brightness. Observed fluctuation is explained by fluctuation of photon noise, shot noise of faint sources, and Galactic cirrus. The fluctuations at a few arcminutes scales at short mid-infrared wavelengths (7, 9, and 11 {mu}m) are largely caused by the diffuse Galactic light of the interstellar dust cirrus. At long mid-infrared wavelengths (15, 18, and 24 {mu}m), photon noise is the dominant source of fluctuation over the scale from arcseconds to a few arcminutes. The residual fluctuation amplitude at 200'' after removing these contributions is at most 1.04 {+-} 0.23 nW m{sup -2} sr{sup -1} or 0.05% of the brightness at 24 {mu}m and at least 0.47 {+-} 0.14 nW m{sup -2} sr{sup -1} or 0.02% at 18 {mu}m. We conclude that the upper limit of the fluctuation in the zodiacal light toward the NEP is 0.03% of the sky brightness, taking 2{sigma} error into account.

  9. Demonstration of random projections applied to the retrieval problem of geophysical parameters from hyper-spectral infrared observations.

    PubMed

    Serio, Carmine; Masiello, Guido; Liuzzi, Giuliano

    2016-08-20

    The random projections statistical technique has been used to reduce the dimensionality of the radiance data space generated from high spectral resolution infrared observations. The mathematical inversion of the physical radiative transfer equation for geophysical parameters has been solved in this space of reduced dimensionality. The great advantage of using random projections is that they provide an unified treatment of instrument noise and forward model error, which can be comprehensively modeled with a single variance term. The result is a novel retrieval approach, which combines computational efficiency to possibly improved accuracy of the retrieval products. The novel approach has been demonstrated through application to the Infrared Atmospheric Sounding Interferometer. We have found that state-of-the-art spectroscopy and related line-mixing treatment for the ν2CO2 absorption band, i.e., the fundamental band for temperature retrieval, show an excellent consistency with satellite observations.

  10. Demonstration of random projections applied to the retrieval problem of geophysical parameters from hyper-spectral infrared observations.

    PubMed

    Serio, Carmine; Masiello, Guido; Liuzzi, Giuliano

    2016-08-20

    The random projections statistical technique has been used to reduce the dimensionality of the radiance data space generated from high spectral resolution infrared observations. The mathematical inversion of the physical radiative transfer equation for geophysical parameters has been solved in this space of reduced dimensionality. The great advantage of using random projections is that they provide an unified treatment of instrument noise and forward model error, which can be comprehensively modeled with a single variance term. The result is a novel retrieval approach, which combines computational efficiency to possibly improved accuracy of the retrieval products. The novel approach has been demonstrated through application to the Infrared Atmospheric Sounding Interferometer. We have found that state-of-the-art spectroscopy and related line-mixing treatment for the ν2CO2 absorption band, i.e., the fundamental band for temperature retrieval, show an excellent consistency with satellite observations. PMID:27556974

  11. A Road Map for the Generation of a Near-Infrared Guide Star Catalog for Thirty Meter Telescope Observations

    NASA Astrophysics Data System (ADS)

    Subramanian, Smitha; Subramaniam, Annapurni; Sivarani, T.; Simard, Luc; Anupama, G. C.; Gillies, Kim; Ramaprakash, A. N.; Reddy, B. Eswar

    2016-09-01

    The near-infrared instruments in the upcoming Thirty Meter Telescope (TMT) will be assisted by a multi conjugate Adaptive Optics (AO) system. For the efficient operation of the AO system, during observations, a near-infrared guide star catalog which goes as faint as 22 mag in JVega band is essential and such a catalog does not exist. A methodology, based on stellar atmospheric models, to compute the expected near-infrared magnitudes of stellar sources from their optical magnitudes is developed. The method is applied and validated in JHKs bands for a magnitude range of JVega 16-22 mag. The methodology is also applied and validated using the reference catalog of PAN STARRS. We verified that the properties of the final PAN STARRS optical catalog will satisfy the requirements of TMT IRGSC and will be one of the potential sources for the generation of the final catalog. In a broader context, this methodology is applicable for the generation of a guide star catalog for any existing/upcoming near-infrared telescopes.

  12. Infrared imaging and polarimetric observations of the pulsar wind nebula in SNR G21.5-0.9

    NASA Astrophysics Data System (ADS)

    Zajczyk, A.; Gallant, Y. A.; Slane, P.; Reynolds, S. P.; Bandiera, R.; Gouiffès, C.; Le Floc'h, E.; Comerón, F.; Koch Miramond, L.

    2012-06-01

    We present infrared observations of the supernova remnant G21.5-0.9 with the Very Large Telescope, the Canada-France-Hawaii Telescope and the Spitzer Space Telescope. Using the VLT/ISAAC camera equipped with a narrow-band [Fe II] 1.64 μm filter the entire pulsar wind nebula in SNR G21.5-0.9 was imaged. This led to detection of iron line-emitting material in the shape of a broken ring-like structure following the nebula's edge. The detected emission is limb-brightened. We also detect the compact nebula surrounding PSR J1833-1034, both through imaging with the CFHT/AOB-KIR instrument (K' band) and the IRAC camera (all bands) and also through polarimetric observations performed with VLT/ISAAC (Ks band). The emission from the compact nebula is highly polarised with an average value of the linear polarisation fraction PL^avg ≃ 0.47, and the swing of the electric vector across the nebula can be observed. The infrared spectrum of the compact nebula can be described as a power law of index αIR = 0.7 ± 0.3, and suggests that the spectrum flattens between the infrared and X-ray bands.

  13. Detection of faint broad emission lines in type 2 AGN: I. Near infrared observations and spectral fitting

    NASA Astrophysics Data System (ADS)

    Onori, F.; La Franca, F.; Ricci, F.; Brusa, M.; Sani, E.; Maiolino, R.; Bianchi, S.; Bongiorno, A.; Fiore, F.; Marconi, A.; Vignali, C.

    2016-09-01

    We present medium resolution near infrared spectroscopic observations of 41 obscured and intermediate class AGN (type 2, 1.9 and 1.8; AGN2) with redshift z ≲0.1, selected from the Swift/BAT 70-month catalogue. The observations have been carried out in the framework of a systematic study of the AGN2 near infrared spectral properties and have been executed using ISAAC/VLT, X-shooter/VLT and LUCI/LBT, reaching an average S/N ratio of ˜30 per resolution element. For those objects observed with X-shooter we also obtained simultaneous optical and UV spectroscopy. We have identified a component from the broad line region in 13 out of 41 AGN2, with FWHM >800 km s-1. We have verified that the detection of the broad line region components does not significantly depend on selection effects due to the quality of the spectra, the X-ray or near infrared fluxes, the orientation angle of the host galaxy or the hydrogen column density measured in the X-ray band. The average broad line region components found in AGN2 has a significantly (a factor 2) smaller FWHM if compared with a control sample of type 1 AGN.

  14. Infrared observations of oxidized carbon in comet C/2002 t7 (LINEAR)

    NASA Astrophysics Data System (ADS)

    Anderson, William Michael, Jr.

    2010-11-01

    Cometary nuclei are generally recognized as the most primitive remnants of the early Solar System. Their physical and chemical attributes allow a glimpse into the conditions under which icy bodies formed. Parent volatiles in comets are now routinely studied, and a significant diversity in composition among the comets sampled to date has been demonstrated. This forms the foundation of an emerging cometary taxonomy based on chemical composition. In spring 2004, comet C/2002 T7 (LINEAR) was observed using the facility echelle spectrometer (CSHELL) at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. CSHELL offers seeing-limited spatial resolution and sufficiently high spectral resolving power (R = lambda/Deltalambda ˜ 2.5 x 10 4) to permit line-by-line intensities to be measured along its 30 arc-second slit. Its small pixels favor measurement of molecules released from ices housed in cometary nuclei ("native" ices) over those released from spatially extended sources in the coma. Emission lines from multiple molecular species were targeted in the 3 to 5 mum wavelength region. The observations revealed an extremely rich volatile chemistry in C/2002 T7. I present the chemical composition of oxidized carbon in C/2002 T7 (LINEAR). Carbon monoxide (CO), formaldehyde (H2CO), and methyl alcohol (CH 3OH) were detected simultaneously or nearly simultaneously with H 2O on multiple UT dates spanning 2004 May 3-9 (heliocentric distance Rh = 0.66 -- 0.71 AU) and May 30 - June 2 (R h = 0.99 -- 1.03 AU). I will discuss native production rates, rotational temperatures, and mixing ratios (abundances relative to H2O) for oxidized carbon. My results illustrate that C/2002 T7 (LINEAR) is enriched in CH3OH, while CO is borderline depleted compared to other Oort cloud comets that have been measured. I tested for chemical heterogeneity in C/2002 T7 (LINEAR), both diurnal, presumably associated with rotation of the nucleus, and serial (i.e., over a range in Rh). However, no evidence

  15. Near-infrared observations of young stellar objects in the Rho Ophiuchi dark cloud

    NASA Technical Reports Server (NTRS)

    Greene, Thomas P.; Young, Erick T.

    1992-01-01

    We have conducted an imaging survey of 1.4 sq pc of the Rho Ophiuchi dark cloud in the J, H, and K near-infrared photometric bands. Approximately 337 of our 481 detected sources are associated with the cloud, and we estimate that 48 percent of these have near-infrared excesses, indicative of disks or circumstellar material surrounding these young stellar objects (YSOs). The K-band luminosity function is significantly different in different regions of our survey area, suggesting that YSOs in these regions have different ages or mass functions. We estimate that the entire survey area has a high star-formation efficiency, at roughly 23 percent. Finally, our many newly detected sources provide a relatively large, uniformly sensitive sample of objects for study at longer wavelengths to better determine true source luminosities and evolutionary lifetimes.

  16. Evolution of the dusty infrared luminosity function from z = 0 to z = 2.3 using observations from Spitzer

    NASA Astrophysics Data System (ADS)

    Magnelli, B.; Elbaz, D.; Chary, R. R.; Dickinson, M.; Le Borgne, D.; Frayer, D. T.; Willmer, C. N. A.

    2011-04-01

    Aims: We derive the evolution of the infrared luminosity function (LF) over the last 4/5ths of cosmic time using deep 24 and 70 μm imaging of the GOODS North and South fields. Methods: We use an extraction technique based on prior source positions at shorter wavelengths to build the 24 and 70 μm source catalogs. The majority (93%) of the sources have a spectroscopic (39%) or a photometric redshift (54%) and, in our redshift range of interest (i.e., 1.3 < z < 2.3) s20% of the sources have a spectroscopic redshift. To extend our study to lower 70 μm luminosities we perform a stacking analysis and we characterize the observed L24/(1 + z) vs. L70/(1 + z) correlation. Using spectral energy distribution (SED) templates which best fit this correlation, we derive the infrared luminosity of individual sources from their 24 and 70 μm luminosities. We then compute the infrared LF at zs1.55 ± 0.25 and zs2.05 ± 0.25. Results: We observe the break in the infrared LF up to zs2.3. The redshift evolution of the infrared LF from z = 1.3 to z = 2.3 is consistent with a luminosity evolution proportional to (1 + z)1.0 ± 0.9 combined with a density evolution proportional to (1 + z)-1.1 ± 1.5. At zs2, luminous infrared galaxies (LIRGs: 1011L⊙ < LIR < 1012 L⊙) are still the main contributors to the total comoving infrared luminosity density of the Universe. At zs2, LIRGs and ultra-luminous infrared galaxies (ULIRGs: 1012L⊙ < LIR) account for s49% and s17% respectively of the total comoving infrared luminosity density of the Universe. Combined with previous results using the same strategy for galaxies at z < 1.3 and assuming a constant conversion between the infrared luminosity and star-formation rate (SFR) of a galaxy, we study the evolution of the SFR density of the Universe from z = 0 to z = 2.3. We find that the SFR density of the Universe strongly increased with redshift from z = 0 to z = 1.3, but is nearly constant at higher redshift out to z = 2.3. As part of the

  17. FIRBACK Cosmological Survey With ISO: Observing the Cosmic Infrared Background at 170 microns

    NASA Astrophysics Data System (ADS)

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

    FIRBACK, one of the deepest surveys performed at 170 microns with ISOPHOT, is aimed at the study of the Cosmic Far Infrared Background (CIB). We just summarize here the main results: 1. we studied the footprint of PHOT at 170 microns and check the calibration (see Lagache, 99a) 2. source counts of resolved galaxies suggest strong evolution (see Dole, 99) 3. fluctuations of the CIB are detected (see Lagache, 99)

  18. VVV near-infrared observations of the Swift J174540.2-290037 field

    NASA Astrophysics Data System (ADS)

    Masetti, N.; Saito, R. K.; Rojas, A. F.; Minniti, D.; Contreras, R.

    2016-06-01

    We explored the archival images of the near-infrared (NIR) VVV survey (vvvsurvey.org; Minniti et al. 2010, New Astron., 15, 433) of the Galactic Bulge and inner disk, obtained with the 4.1m VISTA telescope at Cerro Paranal (Chile), containing the soft X-ray error box the transient Swift J174540.2-290037 (ATel #9109) that was recently detected with Swift (see also GCN Circs.

  19. An inverse problem for a wave equation with arbitrary initial values and a finite time of observations

    NASA Astrophysics Data System (ADS)

    Cipolatti, Rolci; Yamamoto, Masahiro

    2011-09-01

    We consider a solution u(p, g, a, b) to an initial value-boundary value problem for a wave equation: \\fl \\partial _t^2 u(x,t) = \\Delta u(x,t) + p(x)u(x,t), \\qquad x \\in \\Omega,\\qquad \\thinspace 0 < t < T\\\\ \\fl u(x,0) = a(x), \\qquad \\partial _tu(x,0) = b(x), \\qquad x \\in \\Omega,\\\\ \\fl u(x,t) = g(x,t), \\qquad x \\in \\partial \\Omega,\\qquad 0 < t < T, and we discuss an inverse problem of determining a coefficient p(x) and a, b by observations of u(p, g, a, b)(x, t) in a neighbourhood ω of ∂Ω over a time interval (0, T) and ∂itu(p, g, a, b)(x, T0), x in Ω, i = 0, 1, with T0 < T. We prove that if T - T0 and T0 are larger than the diameter of Ω, then we can choose a finite number of Dirichlet boundary inputs g1, ..., gN, so that the mapping \\fl \\lbrace u(p,g_j,a_j,b_j)\\vert _{\\omega \\times (0,T)}, \\partial _t^iu(p,g_j,a_j,b_j)(\\cdot,T_0)\\rbrace _{i=0,1, 1\\le j\\le N}\

  20. Finite-time observer-based output-feedback control for the global stabilisation of the PVTOL aircraft with bounded inputs

    NASA Astrophysics Data System (ADS)

    Zavala-Río, A.; Fantoni, I.; Sanahuja, G.

    2016-05-01

    In this work, an output-feedback scheme for the global stabilisation of the planar vertical take-off and landing aircraft with bounded inputs is developed taking into account the positive nature of the thrust. The global stabilisation objective is proven to be achieved avoiding input saturation and by exclusively considering the system positions in the feedback. To cope with the lack of velocity measurements, the proposed algorithm involves a finite-time observer. The generalised versions of the involved finite-time stabilisers have not only permitted to solve the output-feedback stabilisation problem avoiding input saturation, but also provide additional flexibility in the control design that may be used in aid of performance improvements. With respect to previous approaches, the developed finite-time observer-based scheme guarantees the global stabilisation objective disregarding velocity measurements in a bounded input context. Simulation tests corroborate the analytical developments. The study includes further experimental results on an actual flying device.

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

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1: Microwave 89Ghz imageFigure 2: Visible/near infrared sensor

    Hurricane Ivan is the most powerful hurricane to hit the Caribbean in 10 years. On September 7 and 8 it damaged 90 percent of the homes in Grenada and killed at least 16 people as it swept over Grenada, Barbados and the other islands in the area. By Thursday morning on September 9, Ivan's sustained winds reached 160 mph making it a rare category 5 hurricane on the Saffir-Simpson scale. By Monday September 13, Ivan is blamed for 67 deaths and skirts western Cuba with winds clocked at 156 mph. The National Hurricane Center predicted the eye of Ivan will make landfall across Mobile Bay in Alabama late Wednesday or early Thursday.

    These images of Hurricane Ivan were acquired by the AIRS infrared, microwave, and visible sensors on September 15 at 1:30 pm local time as the storm moves in to Alabama. Ivan at category 4 strength is about 150 miles south of Mobile, Alabama and is moving north at 14 mph. Maximum sustained winds are reported to be at 135 mph and extend 105 miles from the center, while tropical storm-force winds extend 290 miles from the center. Ivan pounded the Gulf coast all day Wednesday, and is expected to make landfall between midnight and 3am in Mobile Bay, Alabama.

    This image shows how the storm looks through an AIRS Infrared window channel, and reveals a very large eye - about 75 km (50 miles) across. 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

  2. The instrumentation and the contamination control activity of thermal and near-infrared sensor for carbon observation (TANSO) on GOSAT

    NASA Astrophysics Data System (ADS)

    Urabe, Tomoyuki; Kuze, Akihiko; Hamazaki, Takashi; Baba, Naoko; Minami, Shintaro; Saruwatari, Hideki

    2006-08-01

    The Greenhouse Gases Observing SATellite (GOSAT) is a satellite to monitor the carbon dioxide (CO II) and the methane (CH 4) globally from orbit. Two instruments are accommodated on GOSAT. Thermal And Near infrared Sensor for carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) detects the Short wave infrared (SWIR) reflected on the earth's surface as well as the thermal infrared (TIR) radiated from the ground and the atmosphere. TANSO-FTS is capable of detecting wide spectral coverage, specifically, three narrow bands (0.76, 1.6, and 2 micron) and a wide band (5.5-14.3 micron) with 0.24 wavenumber spectral resolution. TANSO Cloud and Aerosol Imager (TANSO-CAI) is a radiometer of ultraviolet (UV), visible, and SWIR to correct cloud and aerosol interference. The contaminant deposition on the sensors significantly affects the sensing capability. So the spectroscopic contamination control over wide spectral range is required from the process of GOSAT development to on-orbit operation. The paper presents the instrument design of TANSO-FTS and TANSO-CAI, overview of GOSAT contamination control plan, results from spectral analysis of deposited outgas, test result of hydrazine (rocket and satellite thruster propellant) injection to an optical surface, as well as test result from contamination environment monitoring using a vacuum chamber and contamination witness plates.

  3. AKARI INFRARED OBSERVATIONS OF THE SUPERNOVA REMNANT G292.0+1.8: UNVEILING CIRCUMSTELLAR MEDIUM AND SUPERNOVA EJECTA

    SciTech Connect

    Lee, Ho-Gyu; Sakon, Itsuki; Onaka, Takashi; Koo, Bon-Chul; Moon, Dae-Sik; Jeong, Woong-Seob; Kaneda, Hidehiro; Nozawa, Takaya; Kozasa, Takashi E-mail: isakon@astron.s.u-tokyo.ac.j E-mail: koo@astrohi.snu.ac.k E-mail: jeongws@kasi.re.k E-mail: tnozawa@mail.sci.hokudai.ac.j

    2009-11-20

    We present the results of AKARI observations of the O-rich supernova remnant (SNR) G292.0+1.8 using six Infrared Camera (IRC) and four Far-Infrared Surveyor bands covering 2.7-26.5 mum and 50-180 mum, respectively. The AKARI images show two prominent structures; a bright equatorial ring (ER) structure along the east-west direction and an outer elliptical shell structure surrounding the remnant. The ER structure is clumpy and incomplete with its western end opened. The outer shell is almost complete and slightly squeezed along the north-south direction. The central position of the outer shell is approx1' northwest from the embedded pulsar and coincides with the center of the ER structure. In the northern and southwestern regions, there is also faint emission with a sharp boundary beyond the bright shell structure. The ER and the elliptical shell structures were partly visible in optical and/or X-rays, but they are much more clearly revealed in our AKARI images. There is no evident difference in infrared colors of the two prominent structures, which is consistent with the previous proposition that both structures are of circumstellar origin. However, we have detected faint infrared emission of a considerably high 15/24 mum ratio associated with the supernova (SN) ejecta in the southeastern and northwestern areas. Our IRC spectra show that the high ratio is at least partly due to the emission lines from Ne ions in the SN ejecta material. In addition, we detect a narrow, elongated feature outside the SNR shell. We derive the physical parameters of the infrared-emitting dust grains in the shocked circumstellar medium (CSM) and compare the result with model calculations of dust destruction by an SN shock. The AKARI results suggest that the progenitor was at the center of the infrared circumstellar shell in the red supergiant stage and that the observed asymmetry in the SN ejecta could be a result of either a dense CSM in the equatorial plane and/or an asymmetric

  4. Observation of Trans-Ethanol and Gauche-Ethanol Complexes with Benzene Using Matrix Isolation Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Amicangelo, Jay; Silbaugh, Matthew J.

    2016-06-01

    Ethanol can exist in two conformers, one in which the OH group is trans to the methyl group (trans-ethanol) and the other in which the OH group is gauche to the methyl group (gauche-ethanol). Matrix isolation infrared spectra of ethanol deposited in 20 K argon matrices display distinct infrared peaks that can be assigned to the trans-ethanol and gauche-ethanol conformers, particularly with the O-H stretching vibrations. Given this, matrix isolation experiments were performed in which ethanol (C_2H_5OH) and benzene (C_6H_6) were co-deposited in argon matrices at 20 K in order to determine if conformer specific ethanol complexes with benzene could be observed in the infrared spectra. New infrared peaks that can be attributed to the trans-ethanol and gauche-ethanol complexes with benzene have been observed near the O-H stretching vibrations of ethanol. The initial identification of the new infrared peaks as being due to the ethanol-benzene complexes was established by performing a concentration study (1:200 to 1:1600 S/M ratios), by comparing the co-deposition spectra with the spectra of the individual monomers, by matrix annealing experiments (35 K), and by performing experiments using isotopically labeled ethanol (C_2D_5OD) and benzene (C_6D_6). Quantum chemical calculations were also performed for the C_2H_5OH-C_6H_6 complexes using density functional theory (B3LYP) and ab initio (MP2) methods. Stable minima were found for the both the trans-ethanol and gauche-ethanol complexes with benzene at both levels of theory and were predicted to have similar interaction energies. Both complexes can be characterized as H-π complexes, in which the ethanol is above the benzene ring with the hydroxyl hydrogen interacting with the π cloud of the ring. The theoretical O-H stretching frequencies for the complexes were predicted to be shifted from the monomer frequencies and from each other and these results were used to make the conformer specific infrared peak assignments

  5. Impacts of field of view configuration of Cross-track Infrared Sounder on clear-sky observations.

    PubMed

    Wang, Likun; Chen, Yong; Han, Yong

    2016-09-01

    Hyperspectral infrared radiance measurements from satellite sensors contain valuable information on atmospheric temperature and humidity profiles and greenhouse gases, and therefore are directly assimilated into numerical weather prediction (NWP) models as inputs for weather forecasting. However, data assimilations in current operational NWP models still mainly rely on cloud-free observations due to the challenge of simulating cloud-contaminated radiances when using hyperspectral radiances. The limited spatial coverage of the 3×3 field of views (FOVs) in one field of regard (FOR) (i.e., spatial gap among FOVs) as well as relatively large footprint size (14 km) in current Cross-track Infrared Sounder (CrIS) instruments limits the amount of clear-sky observations. This study explores the potential impacts of future CrIS FOV configuration (including FOV size and spatial coverage) on the amount of clear-sky observations by simulation experiments. The radiance measurements and cloud mask products (VCM) from the Visible Infrared Imager Radiometer Suite (VIIRS) are used to simulate CrIS clear-sky observation under different FOV configurations. The results indicate that, given the same FOV coverage (e.g., 3×3), the percentage of clear-sky FOVs and the percentage of clear-sky FORs (that contain at least one clear-sky FOV) both increase as the FOV size decreases. In particular, if the CrIS FOV size were reduced from 14 km to 7 km, the percentage of clear-sky FOVs increases from 9.02% to 13.51% and the percentage of clear-sky FORs increases from 18.24% to 27.51%. Given the same FOV size but with increasing FOV coverage in each FOR, the clear-sky FOV observations increases proportionally with the increasing sampling FOVs. Both reducing FOV size and increasing FOV coverage can result in more clear-sky FORs, which benefit data utilization of NWP data assimilation. PMID:27607289

  6. Impacts of field of view configuration of Cross-track Infrared Sounder on clear-sky observations.

    PubMed

    Wang, Likun; Chen, Yong; Han, Yong

    2016-09-01

    Hyperspectral infrared radiance measurements from satellite sensors contain valuable information on atmospheric temperature and humidity profiles and greenhouse gases, and therefore are directly assimilated into numerical weather prediction (NWP) models as inputs for weather forecasting. However, data assimilations in current operational NWP models still mainly rely on cloud-free observations due to the challenge of simulating cloud-contaminated radiances when using hyperspectral radiances. The limited spatial coverage of the 3×3 field of views (FOVs) in one field of regard (FOR) (i.e., spatial gap among FOVs) as well as relatively large footprint size (14 km) in current Cross-track Infrared Sounder (CrIS) instruments limits the amount of clear-sky observations. This study explores the potential impacts of future CrIS FOV configuration (including FOV size and spatial coverage) on the amount of clear-sky observations by simulation experiments. The radiance measurements and cloud mask products (VCM) from the Visible Infrared Imager Radiometer Suite (VIIRS) are used to simulate CrIS clear-sky observation under different FOV configurations. The results indicate that, given the same FOV coverage (e.g., 3×3), the percentage of clear-sky FOVs and the percentage of clear-sky FORs (that contain at least one clear-sky FOV) both increase as the FOV size decreases. In particular, if the CrIS FOV size were reduced from 14 km to 7 km, the percentage of clear-sky FOVs increases from 9.02% to 13.51% and the percentage of clear-sky FORs increases from 18.24% to 27.51%. Given the same FOV size but with increasing FOV coverage in each FOR, the clear-sky FOV observations increases proportionally with the increasing sampling FOVs. Both reducing FOV size and increasing FOV coverage can result in more clear-sky FORs, which benefit data utilization of NWP data assimilation.

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

    NASA Technical Reports Server (NTRS)

    Danchi, William

    2010-01-01

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

  8. Cloud-Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO) Spacecraft: Independent Technical Assessment

    NASA Technical Reports Server (NTRS)

    Gilbrech, Richard J.; McManamen, John P.; Wilson, Timmy R.; Robinson, Frank; Schoren, William R.

    2004-01-01

    CALIPSO is a joint science mission between the CNES, LaRC and GSFC. It was selected as an Earth System Science Pathfinder satellite mission in December 1998 to address the role of clouds and aerosols in the Earth's radiation budget. The spacecraft includes a NASA light detecting and ranging (LIDAR) instrument, a NASA wide-field camera and a CNES imaging infrared radiometer. The scope of this effort was a review of the Proteus propulsion bus design and an assessment of the potential for personnel exposure to hydrazine propellant.

  9. VVV near-infrared observations of the Swift J174540.7-290015 field

    NASA Astrophysics Data System (ADS)

    Masetti, N.; Saito, R. K.; Rojas, A. F.; Minniti, D.

    2016-02-01

    Following the outburst of the Galactic Center X-ray transient Swift J174540.7-290015 (ATel #8649, #8684) and its arcsec-sized soft X-ray localization (ATel #8649), we searched the archival frames of the near-infrared (NIR) VVV survey (vvvsurvey.org; Minniti et al. 2010, New Astron., 15, 433) covering the Galactic Bulge and inner arms, and obtained with the 4.1m VISTA telescope at Cerro Paranal (Chile); this search was made in order to look for a possible quiescent NIR counterpart to the aforementioned X-ray transient.

  10. VVV near-infrared observations of the GRS 1736-297 field

    NASA Astrophysics Data System (ADS)

    Masetti, N.; Saito, R. K.; Rojas, A. F.; Minniti, D.

    2016-02-01

    After the announcement of the arcsec-sized soft X-ray error box (ATel #8704) of the X-ray source GRS 1736-297 which recently underwent an active phase at high energies (ATel #8698), we searched the archival frames of the near-infrared (NIR) VVV survey (vvvsurvey.org; Minniti et al. 2010, New Astron., 15, 433) of the Galactic Bulge and inner disk, obtained with the 4.1m VISTA telescope at Cerro Paranal (Chile), to look for the presence of NIR objects within the Swift/XRT error circle reported in ATel #8704.

  11. Cloud-Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO) Spacecraft: Independent Technical Assessment

    NASA Technical Reports Server (NTRS)

    Gilbrech, Richard J.; McManamen, John P.; Wilson, Timmy R.; Robinson, Frank; Schoren, William R.

    2005-01-01

    CALIPSO is a joint science mission between the CNES, LaRC and GSFC. It was selected as an Earth System Science Pathfinder satellite mission in December 1998 to address the role of clouds and aerosols in the Earth's radiation budget. The spacecraft includes a NASA light detecting and ranging (LIDAR) instrument, a NASA wide-field camera and a CNES imaging infrared radiometer. The scope of this effort was a review of the Proteus propulsion bus design and an assessment of the potential for personnel exposure to hydrazine propellant.

  12. Potentially Hazardous Asteroid (85989) 1999 JD6: Radar, Infrared, and Lightcurve Observations and a Preliminary Shape Model

    NASA Astrophysics Data System (ADS)

    Marshall, Sean E.; Howell, Ellen S.; Brozović, Marina; Taylor, Patrick A.; Campbell, Donald B.; Benner, Lance A. M.; Naidu, Shantanu P.; Giorgini, Jon D.; Jao, Joseph S.; Lee, Clement G.; Richardson, James E.; Rodriguez-Ford, Linda A.; Rivera-Valentin, Edgard G.; Ghigo, Frank; Kobelski, Adam; Busch, Michael W.; Pravec, Petr; Warner, Brian D.; Reddy, Vishnu; Hicks, Michael D.; Crowell, Jenna L.; Fernandez, Yanga R.; Vervack, Ronald J.; Nolan, Michael C.; Magri, Christopher; Sharkey, Benjamin; Bozek, Brandon

    2015-11-01

    We report observations of potentially hazardous asteroid (85989) 1999 JD6, which passed 0.048 AU from Earth (19 lunar distances) during its close approach on July 25, 2015. During eleven days between July 15 and August 4, 2015, we observed 1999 JD6 with the Goldstone Solar System Radar and with Arecibo Observatory's planetary radar, including bistatic reception of some Goldstone echoes at Green Bank. We obtained delay-Doppler radar images at a wide range of latitudes, with range resolutions varying from 7.5 to 150 meters per pixel, depending on the observing conditions. We acquired near-infrared spectra from the NASA InfraRed Telescope Facility (IRTF) on two nights in July 2015, at wavelengths from 0.75 to 5.0 microns, showing JD6's thermal emission. We also obtained optical lightcurves from Ondrejov Observatory (in 1999), Table Mountain Observatory (in 2000), and Palmer Divide Station (in 2015). Previous observers had suggested that 1999 JD6 was most likely an elongated object, based on its large lightcurve amplitude of 1.2 magnitudes (Szabo et al. 2001; Polishook and Brosch 2008; Warner 2014). The radar images reveal an elongated peanut-shaped object, with two lobes separated by a sharp concavity. JD6's maximum diameter is about two kilometers, and its larger lobe is approximately 50% longer than its smaller lobe. The larger lobe has a concavity on its end. We will present more details on the shape and rotation state of 1999 JD6, as well as its surface properties from optical and infrared data and thermal modeling.

  13. VERY LARGE ARRAY OBSERVATIONS OF AMMONIA IN INFRARED-DARK CLOUDS. II. INTERNAL KINEMATICS

    SciTech Connect

    Ragan, Sarah E.; Bergin, Edwin A.; Heitsch, Fabian; Wilner, David

    2012-02-20

    Infrared-dark clouds (IRDCs) are believed to be the birthplaces of rich clusters and thus contain the earliest phases of high-mass star formation. We use the Green Bank Telescope and Very Large Array maps of ammonia (NH{sub 3}) in six IRDCs to measure their column density and temperature structure (Paper 1), and here, we investigate the kinematic structure and energy content. We find that IRDCs overall display organized velocity fields, with only localized disruptions due to embedded star formation. The local effects seen in NH{sub 3} emission are not high-velocity outflows but rather moderate (few km s{sup -1}) increases in the linewidth that exhibit maxima near or coincident with the mid-infrared emission tracing protostars. These linewidth enhancements could be the result of infall or (hidden in NH{sub 3} emission) outflow. Not only is the kinetic energy content insufficient to support the IRDCs against collapse, but also the spatial energy distribution is inconsistent with a scenario of turbulent cloud support. We conclude that the velocity signatures of the IRDCs in our sample are due to active collapse and fragmentation, in some cases augmented by local feedback from stars.

  14. Cast Glance Near Infrared Imaging Observations of the Space Shuttle During Hypersonic Re-Entry

    NASA Technical Reports Server (NTRS)

    Tack, Steve; Tomek, Deborah M.; Horvath, Thomas J.; Verstynen, Harry A.; Shea, Edward J.

    2010-01-01

    High resolution calibrated infrared imagery of the Space Shuttle was obtained during hypervelocity atmospheric entries of the STS-119, STS-125 and STS128 missions and has provided information on the distribution of surface temperature and the state of the airflow over the windward surface of the Orbiter during descent. This data collect was initiated by NASA s Hypersonic Thermodynamic Infrared Measurements (HYTHIRM) team and incorporated the use of air- and land-based optical assets to image the Shuttle during atmospheric re-entry. The HYTHIRM objective is to develop and implement a set of mission planning tools designed to establish confidence in the ability of an existing optical asset to reliably acquire, track and return global quantitative surface temperatures of the Shuttle during entry. On Space Shuttle Discovery s STS-119 mission, NASA flew a specially modified thermal protection system tile and instrumentation package to monitor heating effects from boundary layer transition during re-entry. On STS-119, the windward airflow on the port wing was deliberately disrupted by a four-inch wide and quarter-inch tall protuberance built into the modified tile. In coordination with this flight experiment, a US Navy NP-3D Orion aircraft was flown 28 nautical miles below Discovery and remotely monitored surface temperature of the Orbiter at Mach 8.4 using a long-range infrared optical package referred to as Cast Glance. Approximately two months later, the same Navy Cast Glance aircraft successfully monitored the surface temperatures of the Orbiter Atlantis traveling at approximately Mach 14.3 during its return from the successful Hubble repair mission. In contrast to Discovery, Atlantis was not part of the Boundary Layer Transition (BLT) flight experiment, thus the vehicle was not configured with a protuberance on the port wing. In September 2009, Cast Glance was again successful in capturing infrared imagery and monitoring the surface temperatures on Discovery s next

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

    SciTech Connect

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

    2014-05-20

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

  16. Evolutionary dynamics in finite populations can explain the full range of cooperative behaviors observed in the centipede game.

    PubMed

    Rand, David G; Nowak, Martin A

    2012-05-01

    Classical economic models make behavioral predictions based on the assumption that people are fully rational and care only about maximizing their own payoffs. Although this approach successfully explains human behavior in many situations, there is a wealth of experimental evidence demonstrating conditions where people deviate from the predictions of these models. One setting that has received particular attention is fixed length repeated games. Iterating a social dilemma can promote cooperation through direct reciprocity, even if it is common knowledge that all players are rational and self-interested. However, this is not the case if the length of the game is known to the players. In the final round, a rational player will defect, because there is no future to be concerned with. But if you know the other player will defect in the last round, then you should defect in the second to last round, and so on. This logic of backwards induction leads to immediate defection as the only rational (sub-game perfect Nash equilibrium) strategy. When people actually play such games, however, immediate defection is rare. Here we use evolutionary dynamics in finite populations to study the centipede game, which is designed to explore this issue of backwards induction. We make the following observation: since full cooperation can risk-dominate immediate defection in the centipede game, stochastic evolutionary dynamics can favor both delayed defection and even full cooperation. Furthermore, our evolutionary model can quantitatively reproduce human behavior from two experiments by fitting a single free parameter, which is the product of population size and selection intensity. Thus we provide evidence that people's cooperative behavior in fixed length games, which is often called 'irrational', may in fact be the favored outcome of natural selection.

  17. Optical and Infrared Observations of the Black Hole X-Ray Binary XTE J1118+480

    NASA Astrophysics Data System (ADS)

    Gelino, D. M.; Balman, S.; Kiziloglu, U.; Yilmaz, A.; Kalemci, E.; Tomsick, J. A.

    2003-12-01

    We present optical and near infrared observations of XTE J1118+480, a black hole X-ray transient. The data were obtained with the Kitt Peak National Observatory 2.1 m telescope and the Tubitak National Observatory 1.5 m Russian-Turkish telescope, and are modeled with the WD98 light curve modeling program to find the inclination of the system, and hence, the mass of the black hole. As the distorted companion orbits the black hole, the observed flux rises and falls in a predictable manner, giving rise to ``ellipsoidal variations.'' By modeling the variations observed during X-ray quiescence, we determine the orbital inclination of the system. Both optical and infrared data are needed to fully account for any source of flux that may contaminate the ellipsoidal variations, as a constant source of light will dilute the variations giving an artificially lower inclination angle and higher black hole mass. Once the inclination is known, it is combined with the observed mass function and mass ratio (q = (M2)/(M_1)) to find the mass of the black hole. This project is partially supported by a Center for Astrophysics and Space Sciences (CASS) Postdoctoral Fellowship.

  18. Retrieval of ice cloud properties using an optimal estimation algorithm and MODIS infrared observations: 2. Retrieval evaluation

    NASA Astrophysics Data System (ADS)

    Wang, Chenxi; Platnick, Steven; Zhang, Zhibo; Meyer, Kerry; Wind, Gala; Yang, Ping

    2016-05-01

    An infrared-based optimal estimation (OE-IR) algorithm for retrieving ice cloud properties is evaluated. Specifically, the implementation of the algorithm with MODerate resolution Imaging Spectroradiometer (MODIS) observations is assessed in comparison with the operational retrieval products from MODIS on the Aqua satellite (MYD06), Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), and the Imaging Infrared Radiometer (IIR); the latter two instruments fly on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite in the Afternoon Constellation (A-Train) with Aqua. The results show that OE-IR cloud optical thickness (τ) and effective radius (reff) retrievals perform best for ice clouds having 0.5 < τ < 7 and reff < 50 µm. For global ice clouds, the averaged retrieval uncertainties of τ and reff are 19% and 33%, respectively. For optically thick ice clouds with τ larger than 10, however, the τ and reff retrieval uncertainties can exceed 30% and 50%, respectively. For ice cloud top height (h), the averaged global uncertainty is 0.48 km. Relatively large h uncertainty (e.g., > 1 km) occurs for τ < 0.5. Analysis of 1 month of the OE-IR retrievals shows large τ and reff uncertainties in storm track regions and the southern oceans where convective clouds are frequently observed, as well as in high-latitude regions where temperature differences between the surface and cloud top are more ambiguous. Generally, comparisons between the OE-IR and the operational products show consistent τ and h retrievals. However, obvious differences between the OE-IR and the MODIS Collection 6 reff are found.

  19. Cosmological observables, infrared growth of fluctuations, and scale-dependent anisotropies

    NASA Astrophysics Data System (ADS)

    Giddings, Steven B.; Sloth, Martin S.

    2011-09-01

    We simplify and extend semiclassical methods in inflationary cosmology that capture leading IR corrections to correlators. Such IR effects can be absorbed into a coordinate change when examining sufficiently local observables, but not when comparing observations at large separation in scales, such as seen by a late-time observer. The analysis is facilitated by definition of a scale-dependent metric and physical momentum. These assist definition of “IR-safe” observables seen by a postinflationary observer, which are contrasted to those based on the local geometry of the reheating surface. For the former observables, the observer’s horizon provides an effective IR cutoff. IR growth of fluctuations contributes to enhanced statistical inhomogeneities/anisotropies at short scales, observation of which by a present-day observer might be sought in 21 cm measurements. Such IR corrections are argued to become large for a very late-time observer.

  20. Characteristics of Water Vapor Under Partially Cloudy Conditions: Observations by the Atmospheric Infrared Sounder (AIRS)

    NASA Astrophysics Data System (ADS)

    Fishbein, E.

    2003-12-01

    The variability and quality of tropical water vapor derived from the Atmospheric Infrared Sounder (AIRS) are characterized. Profiles of water vapor, temperature and surface characteristics (states) are derived from coincident Advance Microwave Sounding Unit (AMSU) and 3x3 sets of AIRS footprints. States are obtained under partially cloudy conditions by estimating the radiances emitted from the clear portions of the AIRS footprints. This procedure, referred to as cloud clearing, amplifies the measurement noise, and the amplification increases with cloud amount and uniformity. Cumulus and stratus cloud amount are related to the water vapor saturation, and noise amplification and water vapor amount may be partially correlated. The correlations between the uncertainty of retrieved water vapor, cloudiness and noise amplification are characterized. Retrieved water vapor is generally good when the amplification is less than three. Water vapor profiles are compared with correlative data, such as radiosondes and numerical weather center analyses and are in relatively good agreement in the lower troposphere

  1. SUBMILLIMETER OBSERVATIONS OF DENSE CLUMPS IN THE INFRARED DARK CLOUD G049.40-00.01

    SciTech Connect

    Kang, Miju; Choi, Minho; Bieging, John H.; Rho, Jeonghee; Tsai, Chao-Wei

    2011-12-20

    We obtained 350 and 850 {mu}m continuum maps of the infrared dark cloud G049.40-00.01. Twenty-one dense clumps were identified within G049.40-00.01 based on the 350 {mu}m continuum map with an angular resolution of about 9.''6. We present submillimeter continuum maps and report physical properties of the clumps. The masses of clumps range from 50 to 600 M{sub Sun }. About 70% of the clumps are associated with bright 24 {mu}m emission sources, and they may contain protostars. The two most massive clumps show extended, enhanced 4.5 {mu}m emission indicating vigorous star-forming activity. The clump-size-mass distribution suggests that many of them are forming high-mass stars. G049.40-00.01 contains numerous objects in various evolutionary stages of star formation, from pre-protostellar clumps to H II regions.

  2. Optical system of borescope for flame observation in visible (VIS) and infrared (NIR) part of light

    NASA Astrophysics Data System (ADS)

    Keprt, Jirí; Pospíšil, Ladislav; Hrabovský, Miroslav; Bartonek, Ludek

    2014-12-01

    To show flames in the visible and low infrared regions of radiation in the wavelength range from 400 nm to 2000 nm a design of optical systems technical borescope is presented. The proposed glass and technical parameters of the optical system correspond to the diameters of the lens elements and their distance of the borescope for VIS only. The correction lengths and distances of images are approximately the same and also correspond to the mechanical construction of the existing borescope for visible light. To record images in the wavelength range from 800 nm to 1000 nm it is possible to use the classic black-and-white cameras, e.g. OSCAR OS-458. Recording wavelengths in the range of 900 nm to 1700 nm allows, for example, InGaAs camera Bobcat 1.7-320.

  3. Observations of Blazar S5 0716+714 With Ground Based Telescopes and the Spitzer Infrared Space Telescope

    NASA Astrophysics Data System (ADS)

    Adkins, Jeffery; Lacy, M.; Morton, A.; Travagli, T.; Mulaveesala, M.; Santiago, J.; Rapp, S.; Stefaniak, L.

    2006-12-01

    The Gamma-Ray Large Area Space Telescope (GLAST) to be launched in 2007 has a proposed observing list that includes AGNs and Polars bright enough to be observed optically by amateurs and students. This observing list is maintained by the Global Telescope Network (GTN). One of our targets, S5 0716+714, was observed with the Spitzer Space Telescope MIPS and IRAC instruments and also using ground based telescopes. Observations were made in seven infrared bands with Spitzer. Additional observations made from the ground by students, amateur astronomers, and college observatories in R,V, and I were nearly simultaneous with the Spitzer observations. This data were used to construct light curves over the course of the observation and the Spectral Energy Distribution (SED) of the target using all the sources. These data were compared to models of the dust emission from the torus, synchrotron emission from the radio core, and thermal emission from the accretion disk to determine the relative importance of the different emission mechanisms in this object as a function of wavelength. Results were compared to observations of 4C 29.45 made last year. This research was supported by the Spitzer Science Center, the National Optical Astronomy Observatory, and the California Department of Education's Specialized Secondary Program.

  4. Ground-based infrared observations of variable IRAS sources as candidates for late asymptotic giant branch stars

    NASA Technical Reports Server (NTRS)

    Kwok, Sun; Boreiko, R. T.; Hrivnak, Bruce J.

    1987-01-01

    Analysis of the color distribution of OH/IR stars and IRAS low-resolution spectra class 30 objects suggests the presence of a well-defined evolutionary sequence which is populated by late asymptotic giant branch (LAGB) stars. The paper reports ground-based identification and infrared photometry of 10 candidates of news LAGB stars. None of the selected sources are found to have optical counterparts, and eight of the 10 show a strong 10-micron silicate absorption feature. It is suggested that these stars represent an invisible extension of extreme Mira variables and are some of the most evolved stars observed to date.

  5. The Study of Dusty Star-Forming Galaxies in the Early Universe Through Far-Infrared Observations

    NASA Astrophysics Data System (ADS)

    Calanog, Jae Alyson

    In this thesis I use far-infrared (far-IR) observations performed by the Herschel Space Observatory to study dusty star-forming galaxies, which are believed to be the likely progenitors of massive elliptical galaxies. More specifically, I investigate the far-IR emission of dust-obscured galaxies (DOGs), analyze the near-IR imaging of Herschel-selected lensed galaxies, and investigate the rest-frame UV emission of HFLS3, a z = 6.34 Herschel-selected starburst.

  6. Nitrogen Isotopic Ratio in Jupiter's Atmosphere from Observations by Composite Infrared Spectrometer (CIRS) on the Cassini Spacecraft

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    The Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft made infrared observations of Jupiter's atmosphere during the flyby in December 2000 to January 2001. The unique database in the 600-1400/cm region with 0.53 and 2.8/cm spectral resolutions obtained from the observations permits retrieval of global maps of the thermal structure and composition of Jupiter's atmosphere including the distributions of (14)NH3 and (15)NH3. Analysis of Jupiter's ammonia distributions from three isolated (15)NH3 spectral lines in eight latitudes is presented for evaluation of the nitrogen isotopic ratio. The nitrogen isotopic ratio (14)N/(15)N (or (15)N/(14)N) in Jupiter's atmosphere in this analysis is calculated to be: 448 +/- 62 ((2.23 +/- 0.31) x 10(exp -3)). This value of the ratio determined from CIRS data is found to be in very close agreement with the value previously obtained from the measurements by the Galileo Probe Mass Spectrometer. Some possible mechanisms to account for the variation of Jupiter's observed isotopic ratio relative to various astrophysical environments are discussed.

  7. A development of cloud top height retrieval using thermal infrared spectra observed with GOSAT and comparison with CALIPSO data

    NASA Astrophysics Data System (ADS)

    Someya, Yu; Imasu, Ryoichi; Saitoh, Naoko; Ota, Yoshifumi; Shiomi, Kei

    2016-05-01

    An algorithm based on CO2 slicing, which has been used for cirrus cloud detection using thermal infrared data, was developed for high-resolution radiance spectra from satellites. The channels were reconstructed based on sensitivity height information of the original spectral channels to reduce the effects of measurement errors. Selection of the reconstructed channel pairs was optimized for several atmospheric profile patterns using simultaneous studies assuming a cloudy sky. That algorithm was applied to data by the Greenhouse gases Observing SATellite (GOSAT). Results were compared with those obtained from the space-borne lidar instrument on-board Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). Monthly mean cloud amounts from the slicing generally agreed with those from CALIPSO observations despite some differences caused by surface temperature biases, optically very thin cirrus, multilayer structures of clouds, extremely low cloud tops, and specific atmospheric conditions. Comparison of coincident data showed good agreement, except for some cases, and revealed that the improved slicing method is more accurate than the traditional slicing method. Results also imply that improved slicing can detect low-level clouds with cloud top heights as low as approximately 1.5 km.

  8. Spectral signatures of soil, snow and sea ice as observed by passive microwave and thermal infrared techniques

    NASA Technical Reports Server (NTRS)

    Schmugge, T.

    1984-01-01

    There have been many passive microwave observations of soil, snow, and sea ice surfaces made during the past several years. These measurements have been from tower, aircraft, and spacecraft platforms covering the wavelength range from 0.8 cm to 50 cm. Based on these data it can be concluded that the longer wavelengths (greater than 5 cm) are more effective for soil moisture observations because of a greater capability to penetrate vegetation, while the shorter wavelengths (1 to 3 cm) are best for snow and sea ice observations since the dominant process is volume scattering by the ice grains in the snow and the brine cells in sea ice. Because it is the intensity of a thermal emission process that is being measured, thermal infrared measurements are necessary to separate the emissivity and temperature effects in the microwave emission.

  9. Observations of Infrared Radiative Cooling in the Thermosphere on Daily to Multiyear Timescales from the TIMED/SABER Instrument

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.; Hunt, Linda A.; Marshall, B. Thomas; Martin-Torres, F. Javier; Mertens, Christopher J.; Russell, James M., III; Remsberg, Ellis E.; Lopez-Puertas, Manuel; Picard, Richard; Winick, Jeremy; Wintersteiner, Peter; Thompson, R. Earl; Gordley, Larry L.

    2009-01-01

    We present observations of the infrared radiative cooling by carbon dioxide (CO2) and nitric oxide (NO) in Earth s thermosphere. These data have been taken over a period of 7 years by the SABER instrument on the NASA TIMED satellite and are the dominant radiative cooling mechanisms for the thermosphere. From the SABER observations we derive vertical profiles of radiative cooling rates (W/cu m), radiative fluxes (W/sq m), and radiated power (W). In the period from January 2002 through January 2009 we observe a large decrease in the cooling rates, fluxes, and power consistent with the declining phase of solar cycle. The power radiated by NO during 2008 when the Sun exhibited few sunspots was nearly one order of magnitude smaller than the peak power observed shortly after the mission began. Substantial short-term variability in the infrared emissions is also observed throughout the entire mission duration. Radiative cooling rates and radiative fluxes from NO exhibit fundamentally different latitude dependence than do those from CO2, with the NO fluxes and cooling rates being largest at high latitudes and polar regions. The cooling rates are shown to be derived relatively independent of the collisional and radiative processes that drive the departure from local thermodynamic equilibrium (LTE) in the CO2 15 m and the NO 5.3 m vibration-rotation bands. The observed NO and CO2 cooling rates have been compiled into a separate dataset and represent a climate data record that is available for use in assessments of radiative cooling in upper atmosphere general circulation models.

  10. Remote sensing of greenhouse gases (CO2 and CH4) using hyperspectral observations in the thermal infrared

    NASA Astrophysics Data System (ADS)

    Crevoisier, Cyril; Chedin, Alain; Nobileau, Delphine; Armante, Raymond; Thonat, Thibaud; Scott, Noelle A.

    Densely sampling the atmosphere in time and space, satellite measurements of the distribution of global atmospheric CO2 concentration could in principle provide a way to constrain atmo-spheric inversions of CO2 surface fluxes. Until the recent launch of the first dedicated CO2 observing instrument JAXA/GOSAT in January 2009, information on CO2 and other green-house gas atmospheric distribution have been obtained for several years from thermal infrared sounders, such as the Atmospheric Infrared Sounder (AIRS) launched onboard the NASA/Aqua satellite in May 2002 or the Infrared Atmospheric Sounding Interferometer (IASI) launched on-board the European MetOp platform in October 2006. We use coupled observations in the thermal infrared from IASI, and in the microwave from the Advanced Microwave Sounding Unit (AMSU), also launched onboard MetOp, to retrieve mid-to-upper tropospheric contents of carbon dioxide (CO2) and methane (CH4) in clear-sky conditions, in the tropics. Thermal observations, sensitive to both temperature and either CO2 or CH4, are used in conjunction with microwave observations, only sensitive to temperature, to decorrelate both signals through a non-linear inference scheme based on neural networks. A key point of this approach is that no use is made of prior information in terms of gas seasonality, trend, or geographical patterns. The precision of the IASI retrieval is estimated to be about 2 ppmv (less than 1 Features of the retrieved CO2-CH4 space-time distributions include: (1) a CO2 trend of 2.1 ppmv.yr-1 in average, and a CH4 trend of 10 ppbv.yr-1 in the last couple of years, which confirms the recent increase of methane detected at surface stations; (2) a strong seasonal cycle in the northern tropics, and a lower seasonal cycle in the southern tropics, in agreement with in-situ measurements; in particular, comparison between AIRS and IASI retrievals highlights the time-lag of CO2 cycle while transported from the surface to the upper troposphere

  11. Ground-based near-infrared observations of the Venus nightside: The thermal structure and water abundance near the surface

    NASA Astrophysics Data System (ADS)

    Meadows, V. S.; Crisp, D.

    We used ground-based near-infrared (NIR) observations of thermal emission from the Venus nightside to determine the temperature structure and water vapor distribution between the surface and the 6-km level. We show that emission from spectral windows near 1.0, 1.1, and 1.18 μm originates primarily from the surface and lowest scale height (~16 km). These windows include absorption by weak H2O and CO2 lines and by the far wings of lines in strong nearby CO2 bands. Rayleigh scattering by the 90-bar CO2 atmosphere and Mie scattering by the H2SO4 clouds attenuate this emission, but add little to its spectral dependence. Surface topography also modulates this NIR thermal emission because high-elevation regions are substantially cooler and emit less thermal radiation than the surrounding plains. These contributions to the emission are clearly resolved in moderate-resolution (λ/Δλ~400) spectral image cubes of the Venus nightside acquired with the infrared imaging spectrometer (IRIS) on the Anglo-Australian Telescope (AAT) in 1991. To analyze these observations, we used a radiative transfer model that includes all of the radiative processes listed above. Synthetic spectra for several topographic elevations were combined with Pioneer Venus altimetry data to generate spatially resolved maps of the NIR thermal emission. Comparisons between these synthetic radiance maps and the IRIS observations indicate no near-infrared signature of the surface emissivity differences seen at microwave wavelengths by the Magellan orbiter. Assuming constant surface emissivity in the near-infrared, we derive nightside averaged temperature lapse rates of -7 to -7.5 K/km in the lowest 6 km. These lapse rates are smaller and indicate much greater static stability than those inferred from earlier measurements and greenhouse models (-8 to -8.5 K/km) [Seiff, 1983]. An acceptable fit to the data was obtained with an H2O mixing ratio profile which increases from 20 ppmv at the cloud base to 45 ppmv

  12. Detection of supercooled liquid water-topped mixed-phase clouds >from shortwave-infrared satellite observations

    NASA Astrophysics Data System (ADS)

    NOH, Y. J.; Miller, S. D.; Heidinger, A. K.

    2015-12-01

    Many studies have demonstrated the utility of multispectral information from satellite passive radiometers for detecting and retrieving the properties of cloud globally, which conventionally utilizes shortwave- and thermal-infrared bands. However, the satellite-derived cloud information comes mainly from cloud top or represents a vertically integrated property. This can produce a large bias in determining cloud phase characteristics, in particular for mixed-phase clouds which are often observed to have supercooled liquid water at cloud top but a predominantly ice phase residing below. The current satellite retrieval algorithms may report these clouds simply as supercooled liquid without any further information regarding the presence of a sub-cloud-top ice phase. More accurate characterization of these clouds is very important for climate models and aviation applications. In this study, we present a physical basis and preliminary results for the algorithm development of supercooled liquid-topped mixed-phase cloud detection using satellite radiometer observations. The detection algorithm is based on differential absorption properties between liquid and ice particles in the shortwave-infrared bands. Solar reflectance data in narrow bands at 1.6 μm and 2.25 μm are used to optically probe below clouds for distinction between supercooled liquid-topped clouds with and without an underlying mixed phase component. Varying solar/sensor geometry and cloud optical properties are also considered. The spectral band combination utilized for the algorithm is currently available on Suomi NPP Visible/Infrared Imaging Radiometer Suite (VIIRS), Himawari-8 Advanced Himawari Imager (AHI), and the future GOES-R Advance Baseline Imager (ABI). When tested on simulated cloud fields from WRF model and synthetic ABI data, favorable results were shown with reasonable threat scores (0.6-0.8) and false alarm rates (0.1-0.2). An ARM/NSA case study applied to VIIRS data also indicated promising

  13. Dust in an Extremely Metal-Poor Galaxy: Mid-infrared Observations ofSBS 0335-052

    NASA Astrophysics Data System (ADS)

    Thuan, Trinh X.; Sauvage, Marc; Madden, Suzanne

    1999-05-01

    The metal-deficient (Z=Zsolar/41) blue compact dwarf galaxy SBS 0335-052 was observed with ISOCAM between 5 and 17 μm. With an L12μm/LB ratio of 2.15, the galaxy is unexpectedly bright in the mid-infrared for such a low-metallicity object. The mid-infrared spectrum shows no sign of the unidentified infrared bands, which we interpret as an effect of the destruction of their carriers by the very high UV energy density in SBS 0335-052. The spectral energy distribution (SED) is dominated by a very strong continuum, which makes the ionic lines of [S IV] and [Ne III] very weak. From 5 to 17 μm, the SED can be fitted with a graybody spectrum, modified by an extinction law similar to that observed toward the Galactic center, with an optical depth of AV~19-21 mag. Such a large optical depth implies that a large fraction (as much as ~75%) of the current star formation activity in SBS 0335-052 is hidden by dust with a mass between 3×103 and 5×105 Msolar. Silicate grains that are present as silicate extinction bands at 9.7 and 18 μm can account for the unusual shape of the MIR spectrum of SBS 0335-052. It is remarkable that such a nearly primordial environment contains as much dust as galaxies that are 10 times more metal-rich. If the hidden star formation in SBS 0335-052 is typical of young galaxies at high redshifts, then the cosmic star formation rate derived from UV/optical fluxes would be underestimated. Based on data obtained with ISO, an ESA project with instruments funded by the ESA member states (especially the PI countries: France, Germany, the Netherlands, and the United Kingdom) with the participation of ISAS and NASA.

  14. Infrared Observations of the Candidate LBV 1806-20 and Nearby Cluster Stars1,

    NASA Astrophysics Data System (ADS)

    Eikenberry, S. S.; Matthews, K.; LaVine, J. L.; Garske, M. A.; Hu, D.; Jackson, M. A.; Patel, S. G.; Barry, D. J.; Colonno, M. R.; Houck, J. R.; Wilson, J. C.; Corbel, S.; Smith, J. D.

    2004-11-01

    We report near-infrared photometry, spectroscopy, and speckle imaging of the hot, luminous star we identify as candidate LBV 1806-20. We also present photometry and spectroscopy of three nearby stars, which are members of the same star cluster containing LBV 1806-20 and SGR 1806-20. The spectroscopy and photometry show that LBV 1806-20 is similar in many respects to the luminous ``Pistol star,'' albeit with some important differences. They also provide estimates of the effective temperature and reddening of LBV 1806-20 and confirm distance estimates, leading to a best estimate for the luminosity of this star of greater than 5×106Lsolar. The nearby cluster stars have spectral types and inferred absolute magnitudes that confirm the distance (and thus luminosity) estimate for LBV 1806-20. If we drop kinematic measurements of the distance (15.1+1.8-1.3 kpc), we have a lower limit on the distance of greater than 9.5 kpc and on the luminosity of greater than 2×106Lsolar, based on the cluster stars. If we drop both the kinematic and cluster star indicators for distance, an ammonia absorption feature sets yet another lower limit to the distance of greater than 5.7 kpc, with a corresponding luminosity estimate of greater than 7×105 Lsolar for the candidate LBV 1806-20. Furthermore, on the absis of very high angular resolution speckle images, we determine that LBV 1806-20 is not a cluster of stars but is rather a single star or binary system. Simple arguments based on the Eddington luminosity lead to an estimate of the total mass of LBV 1806-20 (single or binary) exceeding 190Msolar. We discuss the possible uncertainties in these results and their implications for the star formation history of this cluster. Based on data obtained at the Palomar Observatory 200 inch telescope, which is operated by the California Institute of Technology, the Jet Propulsion Laboratory, and Cornell University. This publication makes use of data products from the Two Micron All Sky Survey

  15. Luminous Infrared Galaxies with the Submillimeter Array. IV. 12CO J = 6-5 Observations of VV 114

    NASA Astrophysics Data System (ADS)

    Sliwa, Kazimierz; Wilson, Christine D.; Krips, Melanie; Petitpas, Glen R.; Iono, Daisuke; Juvela, Mika; Matsushita, Satoki; Peck, Alison; Yun, Min

    2013-11-01

    We present high-resolution (~2.''5) observations of 12CO J = 6-5 toward the luminous infrared galaxy VV 114 using the Submillimeter Array. We detect 12CO J = 6-5 emission from the eastern nucleus of VV 114 but do not detect the western nucleus or the central region. We combine the new 12CO J = 6-5 observations with previously published or archival low-J CO observations, which include 13CO J = 1-0 Atacama Large Millimeter/submillimeter Array cycle 0 observations, to analyze the beam-averaged physical conditions of the molecular gas in the eastern nucleus. We use the radiative transfer code RADEX and a Bayesian likelihood code to constrain the temperature (T kin), density (n_{H_{2}}), and column density (N_{^{12CO}}) of the molecular gas. We find that the most probable scenario for the eastern nucleus is a cold (T kin = 38 K), moderately dense (n_{H_{2}} = 102.89 cm-3) molecular gas component. We find that the most probable 12CO to 13CO abundance ratio ([12CO]/[13CO]) is 229, which is roughly three times higher than the Milky Way value. This high abundance ratio may explain the observed high 12CO/ 13CO line ratio (>25). The unusual 13CO J = 2-1/J = 1-0 line ratio of 0.6 is produced by a combination of moderate 13CO optical depths (τ = 0.4-1.1) and extremely subthermal excitation temperatures. We measure the CO-to-H2 conversion factor, αCO, to be 0.5^{+0.6}_{-0.3} M ⊙ (K km s-1 pc2)-1, which agrees with the widely used factor for ultra luminous infrared galaxies of Downes & Solomon (αCO = 0.8 M ⊙ (K km s-1 pc2)-1).

  16. Contrail microphysical properties and radiative forcing over the Northern Hemisphere derived using MODIS infrared observations

    NASA Astrophysics Data System (ADS)

    Bedka, S. T.; Minnis, P.; Duda, D. P.; Spangenberg, D.; Chee, T.; Khlopenkov, K. V.

    2015-12-01

    One of the primary ways that air traffic affects the Earth's radiation budget is through the formation of contrails. In order to quantify the radiative impact of contrails, one must assess their macro and microphysical properties (e.g. contrail temperature, optical depth and effective particle size) as well as the characteristics of the environment in which they occur (e.g. background radiation field and cloud properties). In-situ measurements of contrail microphysical properties are limited, and hence the retrieval of such properties from remotely sensed satellite data is useful. This paper details the ongoing progress being made to retrieve contrail properties and calculate the contrail radiative forcing from 2 years of MODIS (Moderate Resolution Imaging Spectroradiometer) Aqua and Terra data. Contrail microphysical properties from the seasonal months (January, April, July, October) of 2006 and 2012 are derived using an infrared-only heritage algorithm developed at NASA Langley for the Clouds and the Earth's Radiant Energy System (CERES) program. Results are subset by day/night, although the same retrieval algorithm will be used for all granules. Contrail properties and background cloud properties are then used as input into the Fu-Liou radiative transfer model to compute the overall contrail radiative forcing.

  17. Cassini Visual and Infrared Mapping Spectrometer observations of Iapetus: Detection of CO2

    USGS Publications Warehouse

    Buratti, B.J.; Cruikshank, D.P.; Brown, R.H.; Clark, R.N.; Bauer, J.M.; Jaumann, R.; McCord, T.B.; Simonelli, D.P.; Hibbitts, C.A.; Hansen, G.B.; Owen, T.C.; Baines, K.H.; Bellucci, G.; Bibring, J.-P.; Capaccioni, F.; Cerroni, P.; Coradini, A.; Drossart, P.; Formisano, V.; Langevin, Y.; Matson, D.L.; Mennella, V.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, C.; Roush, T.L.; Soderlund, K.; Muradyan, A.

    2005-01-01

    The Visual and Infrared Mapping Spectrometer (VIMS) instrument aboard the Cassini spacecraft obtained its first spectral map of the satellite lapetus in which new absorption bands are seen in the spectra of both the low-albedo hemisphere and the H2O ice-rich hemisphere. Carbon dioxide is identified in the low-albedo material, probably as a photochemically produced molecule that is trapped in H2O ice or in some mineral or complex organic solid. Other absorption bands are unidentified. The spectrum of the low-albedo hemisphere is satisfactorily modeled with a combination of organic tholin, poly-HCN, and small amounts of H2O ice and Fe 2O3. The high-albedo hemisphere is modeled with H 2O ice slightly darkened with tholin. The detection of CO2 in the low-albedo material on the leading hemisphere supports the contention that it is carbon-bearing material from an external source that has been swept up by the satellite's orbital motion. ?? 2005. The American Astronomical Society. All rights reserved.

  18. Infrared Observations of LBV 1806-20 and Nearby Cluster Stars

    NASA Astrophysics Data System (ADS)

    Eikenberry, S.; Matthews, K.; LaVine, J. L.; Garske, M.; Hu, D.; Jackson, M. A.; Patel, S. G.; Barry, D. J.; Colonno, M. R.; Houck, J. R.; Wilson, J. C.; Corbel, S.; Smith, J. D.

    2003-12-01

    We report near-infrared photometry, spectroscopy, and speckle imaging of the hot, luminous star we identify as LBV 1806-20. We also present photometry and spectroscopy of 3 nearby stars, which are members of the same star cluster containing LBV 1806-20 and SGR 1806-20. The spectroscopy and photometry show that LBV 1806-20 is similar in many respects to the luminous ``Pistol Star'', albeit with some important differences. They also provide estimates of the effective temperature and reddening of LBV 1806-20, and confirm distance estimates, leading to an estimate for the luminosity of this star of > 5 × 106 \\ L⊙. The nearby cluster stars have spectral types and inferred absolute magnitudes which confirm the distance (and thus luminosity) estimate for LBV 1806-20. Furthermore, based on very high angular-resolution speckle images, we determine that LBV 1806-20 is not a cluster of stars, but is rather a single star or binary system. Simple arguments based on the Eddington luminosity lead to an estimate of the total mass of LBV 1806-20 (single or binary) exceeding 200 \\ M⊙. We discuss the possible uncertainties in these results, and their implications for the star formation history of this cluster.

  19. Initial Reaction Dynamics of Proteorhodopsin Observed by Femtosecond Infrared and Visible Spectroscopy

    PubMed Central

    Neumann, Karsten; Verhoefen, Mirka-Kristin; Weber, Ingrid; Glaubitz, Clemens; Wachtveitl, Josef

    2008-01-01

    We present a comparative study using femtosecond pump/probe spectroscopy in the visible and infrared of the early photodynamics of solubilized proteorhodopsin (green absorbing variant) in D2O with deprotonated (pD 9.2) and protonated (pD 6.4) primary proton acceptor Asp-97. The vis-pump/vis-probe experiments show a kinetic isotope effect that is more pronounced for alkaline conditions, thus decreasing the previously reported pH-dependence of the primary reaction of proteorhodopsin in H2O. This points to a pH dependent H-bonding network in the binding pocket of proteorhodopsin, that directly influences the primary photo-induced dynamics. The vis-pump/IR-probe experiments were carried out in two different spectral regions and allowed to monitor the retinal C=C (1500 cm−1–1580 cm−1) and C=N stretching vibration as well as the amide I mode of the protein (1590 cm−1–1680 cm−1). Like the FTIR spectra of the K intermediate (PRK–PR difference spectra) in this spectral range, the kinetic parameters and also the quantum efficiency of photo-intermediate formation are found to be virtually independent of the pD value. PMID:18326639

  20. Understanding the Star Formation Process in the Filamentary Dark Cloud GF 9: Near-Infrared Observations

    NASA Technical Reports Server (NTRS)

    Ciardi, David R.; Woodward, Charles E.; Clemens, Dan P.; Harker, David E.; Rudy, Richard J.

    1998-01-01

    We have performed a near-infrared JHK survey of a dense core and a diffuse filament region within the filamentary dark cloud GF 9 (LDN 1082). The core region is associated with the IRAS point source PSC 20503+6006 and is suspected of being a site of star formation. The diffuse filament region has no associated IRAS point sources and is likely quiescent. We find that neither the core nor the filament region appears to contain a Class I or Class II young stellar object. As traced by the dust extinction, the core and filament regions contain 26 and 22 solar mass, respectively, with an average H2 volume density for both regions of approximately 2500/cu cm. The core region contains a centrally condensed extinction maximum with a peak extinction of A(sub v) greater than or approximately equal to 10 mag that appears to be associated with the IRAS point source. The average H2 volume density of the extinction core is approximately 8000/cu cm. The dust within the filament, however, shows no sign of a central condensation and is consistent with a uniform-density cylindrical distribution.

  1. Tracking Jupiter's Quasi-Quadrennial Oscillation and Mid-Latitude Zonal Waves with High Spectral Resolution Mid-Infrared Observations

    NASA Astrophysics Data System (ADS)

    Greathouse, Thomas K.; Orton, Glenn S.; Cosentino, Rick; Morales-Juberias, Raul; Fletcher, Leigh N.; Giles, Rohini Sara; Melin, Henrik; Encrenaz, Therese A.; Fouchet, Thierry; DeWitt, Curtis N.

    2016-10-01

    We report on early results of a long term observational study to track the temporal and 3-dimensional evolution of the Quasi-Quadrennial Oscillation (QQO) and the propagation and evolution of mid-latitude zonal waves in Jupiter's stratosphere. These wave-driven phenomena affect variations in Jupiter's vertical and horizontal temperature field, which can be inferred by measuring methane emission in the thermal infrared near 1245 cm-1. Using TEXES, the Texas Echelon cross-dispersed Echelle Spectrograph, mounted on the NASA Infrared Telescope Facility (IRTF) we observed high-spectral resolution (R=75,000) scan maps of Jupiter's equator to mid-latitudes from January 2012 through to the present. We will present the zonally averaged inferred thermal structure within ±30° latitude of the equator and between 10 and 0.01 mbar, showing the QQO's downward progression along with inferred 3-dimensional thermal maps (latitude, longitude, pressure) displaying a multitude of independent waves and eddies at various latitudes and pressures. These results reveal a vast array of wave activity on Jupiter and will serve to: 1) significantly improve the determination of the period and vertical descent velocity of Jupiter's QQO; 2) measure the zonal wavenumbers, vertical wavelengths, zonal group velocities and lifetimes of transient mid-latitude waves; and 3) record the thermal state of Jupiter's stratosphere in detail prior to, during, and after Juno's prime mission.

  2. Sol-to-Gel Transition in Fast Evaporating Systems Observed by in Situ Time-Resolved Infrared Spectroscopy.

    PubMed

    Innocenzi, Plinio; Malfatti, Luca; Carboni, Davide; Takahashi, Masahide

    2015-06-22

    The in situ observation of a sol-to-gel transition in fast evaporating systems is a challenging task and the lack of a suitable experimental design, which includes the chemistry and the analytical method, has limited the observations. We synthesise an acidic sol, employing only tetraethylorthosilicate, SiCl4 as catalyst and deuterated water; the absence of water added to the sol allows us to follow the absorption from the external environment and the evaporation of deuterated water. The time-resolved data, obtained by attenuated total reflection infrared spectroscopy on an evaporating droplet, enables us to identify four different stages during evaporation. They are linked to specific hydrolysis and condensation rates that affect the uptake of water from external environment. The second stage is characterized by a decrease in hydroxyl content, a fast rise of condensation rate and an almost stationary absorption of water. This stage has been associated with the sol-to-gel transition.

  3. FAR-ULTRAVIOLET OBSERVATIONS OF OUTFLOWS FROM INFRARED-LUMINOUS GALAXIES

    SciTech Connect

    Leitherer, Claus; Wofford, Aida; Chandar, Rupali; Tremonti, Christy A.; Schaerer, Daniel E-mail: wofford@stsci.edu E-mail: tremonti@astro.wisc.edu

    2013-08-01

    We obtained medium-resolution ultraviolet (UV) spectra between 1150 and 1450 A of the four UV-bright, infrared-luminous starburst galaxies IRAS F08339+6517, NGC 3256, NGC 6090, and NGC 7552 using the Cosmic Origins Spectrograph on board the Hubble Space Telescope. The selected sightlines toward the starburst nuclei probe the properties of the recently formed massive stars and the physical conditions in the starburst-driven galactic superwinds. Despite being metal-rich and dusty, all four galaxies are strong Ly{alpha} emitters with equivalent widths ranging between 2 and 13 A. The UV spectra show strong P Cygni-type high-ionization features indicative of stellar winds and blueshifted low-ionization lines formed in the interstellar and circumgalactic medium. We detect outflowing gas with bulk velocities of {approx}400 km s{sup -1} and maximum velocities of almost 900 km s{sup -1}. These are among the highest values found in the local universe and comparable to outflow velocities found in luminous Lyman-break galaxies at intermediate and high redshift. The outflow velocities are unlikely to be high enough to cause escape of material from the galactic gravitational potential. However, the winds are significant for the evolution of the galaxies by transporting heavy elements from the starburst nuclei and enriching the galaxy halos. The derived mass outflow rates of {approx}100 M{sub Sun} yr{sup -1} are comparable to or even higher than the star formation rates. The outflows can quench star formation and ultimately regulate the starburst as has been suggested for high-redshift galaxies.

  4. CHARACTERIZING ULTRAVIOLET AND INFRARED OBSERVATIONAL PROPERTIES FOR GALAXIES. I. INFLUENCES OF DUST ATTENUATION AND STELLAR POPULATION AGE

    SciTech Connect

    Mao Yewei; Kong Xu; Kennicutt, Robert C. Jr.; Hao, Cai-Na; Zhou Xu E-mail: xkong@ustc.edu.cn

    2012-09-20

    The correlation between infrared-to-ultraviolet luminosity ratio and ultraviolet color (or ultraviolet spectral slope), i.e., the IRX-UV (or IRX-{beta}) relation, found in studies of starburst galaxies is a prevalent recipe for correcting extragalactic dust attenuation. Considerable dispersion in this relation discovered for normal galaxies, however, complicates its usability. In order to investigate the cause of the dispersion and to have a better understanding of the nature of the IRX-UV relation, in this paper, we select five nearby spiral galaxies, and perform spatially resolved studies on each of the galaxies, with a combination of ultraviolet and infrared imaging data. We measure all positions within each galaxy and divide the extracted regions into young and evolved stellar populations. By means of this approach, we attempt to discover separate effects of dust attenuation and stellar population age on the IRX-UV relation for individual galaxies. In this work, in addition to dust attenuation, stellar population age is interpreted to be another parameter in the IRX-UV function, and the diversity of star formation histories is suggested to disperse the age effects. At the same time, strong evidence shows the need for more parameters in the interpretation of observational data, such as variations in attenuation/extinction law. Fractional contributions of different components to the integrated luminosities of the galaxies suggest that the integrated measurements of these galaxies, which comprise different populations, would weaken the effect of the age parameter on IRX-UV diagrams. The dependence of the IRX-UV relation on luminosity and radial distance in galaxies presents weak trends, which offers an implication of selective effects. The two-dimensional maps of the UV color and the infrared-to-ultraviolet ratio are displayed and show a disparity in the spatial distributions between the two galaxy parameters, which offers a spatial interpretation of the scatter

  5. PROBING THE INTERSTELLAR MEDIUM OF z {approx} 1 ULTRALUMINOUS INFRARED GALAXIES THROUGH INTERFEROMETRIC OBSERVATIONS OF CO AND SPITZER MID-INFRARED SPECTROSCOPY

    SciTech Connect

    Pope, Alexandra; Kirkpatrick, Allison; Wagg, Jeff; Frayer, David; Armus, Lee; Chary, Ranga-Ram; Desai, Vandana; Daddi, Emanuele; Elbaz, David; Gabor, Jared

    2013-08-01

    We explore the relationship between gas, dust, and star formation in a sample of 12 ultraluminous infrared galaxies (ULIRGs) at high-redshift compared to a similar sample of local galaxies. We present new CO observations and/or Spitzer mid-IR spectroscopy for six 70 {mu}m selected galaxies at z {approx} 1 in order to quantify the properties of the molecular gas reservoir, the contribution of an active galactic nucleus (AGN) to the mid-IR luminosity, and the star formation efficiency (SFE = L{sub IR}/L{sup '}{sub CO}). The mid-IR spectra show strong polycyclic aromatic hydrocarbon (PAH) emission, and our spectral decomposition suggests that the AGN makes a minimal contribution (<25%) to the mid-IR luminosity. The 70 {mu}m selected ULIRGs, which we find to be spectroscopic close pairs, are observed to have high SFE, similar to local ULIRGs and high-redshift submillimeter galaxies, consistent with enhanced IR luminosity due to an ongoing major merger. Combined with existing observations of local and high-redshift ULIRGs, we further compare the PAH, IR, and CO luminosities. We show that the ratio L{sub PAH,6.2}/L{sub IR} decreases with increasing IR luminosity for both local and high-redshift galaxies, but the trend for high-redshift galaxies is shifted to higher IR luminosities; the average L{sub PAH,6.2}/L{sub IR} ratio at a given L{sub IR} is {approx}3 times higher at high-redshift. When we normalize by the molecular gas, we find this trend to be uniform for galaxies at all redshifts and that the molecular gas is correlated with the PAH dust emission. The similar trends seen in the [C II] to molecular gas ratios in other studies suggests that PAH emission, like [C II], continues to be a good tracer of photodissociation regions even at high-redshift. Together the CO, PAH, and far-IR fine structure lines should be useful for constraining the interstellar medium conditions in high-redshift galaxies.

  6. Characterization of Near-Earth Asteroid 2009 KC3 from Radar and Thermal Infrared Observations

    NASA Astrophysics Data System (ADS)

    Taylor, Patrick A.; Howell, E. S.; Nolan, M. C.; Benner, L. A. M.; Brozovic, M.; Giorgini, J. D.; Vervack, R. J.; Fernandez, Y. R.; Magri, C.; Mueller, M.

    2010-10-01

    We will report on the size, shape, spin state, and reflective and thermal properties of C-type, Apollo-class, potentially hazardous, near-Earth asteroid 2009 KC3 (a = 3.2 AU, e = 0.7, i = 10 deg). This object was discovered by the Siding Spring Survey in May 2009 and subsequently observed in the late summer using the Goldstone (8560 MHz, 3.5 cm) and Arecibo (2380 MHz, 12.6 cm) radar systems from August 22-29 as well as with the SpeX instrument on the NASA IRTF on August 30 and September 21. Radar images reveal a roughly spheroidal body about 1.2 km in diameter that is slightly asymmetric and elongated. Tracking of surface features and the echo bandwidth suggest a period near 12 hours, which is in agreement with a period of 11.768 hours found from lightcurve observations (P. Pravec, pers. comm.). A consistent decrease in echo bandwidth during the radar observations implies the line of sight was moving away from the equator. Radar images with resolution as fine as 7.5 m per pixel show an indentation on the leading edge (possibly a crater) and radar-bright features beyond the leading edge. The S-band circular polarization ratio of 0.25 is near the median observed among near-Earth asteroids. Thermal emission between 2 and 4 microns is essentially unchanged in SpeX observations three weeks apart despite a change in phase angle from 98 deg to 49 degrees and an increase in heliocentric distance by 0.1 AU. Furthermore, the thermal parameters derived for 2009 KC3 during a single observation do not accurately predict the thermal emission at a later time in a different viewing geometry. Determination of the shape and spin pole will help us understand how much rotation phase and illumination effects affected the thermal observations.

  7. Ultraviolet and infrared observations of stars with 'quenched' chromospheres and the nature of mass loss

    NASA Technical Reports Server (NTRS)

    Stencel, R. E.; Carpenter, K. G.; Hagen, W.

    1986-01-01

    Previous observational evidence implies that the presence of Ca II emission, a chromospheric indicator, is correlated with the gas/dust ratio in the envelopes of red giant and supergiant stars. An attempt is made to determine whether this correlation can be generalized to all chromospheric activity indicators and the gas/dust ratio. New ultraviolet observations address the strength of UV emission features and the fraction of the total chromospheric flux emitted in various lines. Evidence is found that chromospheres are not completely quenched in the presence of dust, but that significant alteration of relative radiative loss patterns may occur. These observations are interpreted in terms of an instability that converts warm, chromospheric gas into near-surface dust grains and cool gas capable of supporting molecular masing. This supports the dust-driven mass loss scenario for red giant winds.

  8. Stratospheric profiles of nitrogen dioxide observed by Optical Spectrograph and Infrared Imager System on the Odin satellite

    NASA Astrophysics Data System (ADS)

    Sioris, Christopher E.; Haley, Craig S.; McLinden, Chris A.; von Savigny, Christian; McDade, Ian C.; McConnell, Jack C.; Evans, Wayne F. J.; Lloyd, Nicholas D.; Llewellyn, Edward J.; Chance, Kelly V.; Kurosu, Thomas P.; Murtagh, Donal; Frisk, Urban; Pfeilsticker, Klaus; BöSch, Hartmut; Weidner, Frank; Strong, Kimberly; Stegman, Jacek; MéGie, GéRard

    2003-04-01

    Vertical profiles of nitrogen dioxide in the 19-40 km altitude range are successfully retrieved over the globe from Optical Spectrograph and Infrared Imager System (OSIRIS) limb scatter observations in late 2001 and early 2002. The inclusion of multiple scattering in the radiative transfer model used in the inversion algorithm allows for the retrieval of NO2 down to 19 km. The slant column densities, which represent the observations in the inversion, are obtained by fitting the fine structure in normalized radiance spectra over the 435-449 nm range, where NO2 electronic absorption is readily observable because of long light paths through stratospheric layers rich in this constituent. Details of the spectral fitting and inversion algorithm are discussed, including the discovery of a pseudo-absorber associated with pixelated detectors and a new method to verify altitude registration. Comparisons are made with spatially and temporally coincident profile measurements of this photochemically active trace gas. Better than 20% agreement is obtained with all correlative measurements over the common retrieval altitude range, confirming the validity of OSIRIS NO2 profiles. Systematic biases in the number densities are not observed at any altitude. A "snapshot" meridional cross section between 40°N and 70°S is shown from observations during a fraction of an orbit.

  9. A UNIFIED EMPIRICAL MODEL FOR INFRARED GALAXY COUNTS BASED ON THE OBSERVED PHYSICAL EVOLUTION OF DISTANT GALAXIES

    SciTech Connect

    Bethermin, Matthieu; Daddi, Emanuele; Sargent, Mark T.; Elbaz, David; Mullaney, James; Pannella, Maurilio; Hezaveh, Yashar; Le Borgne, Damien; Buat, Veronique; Charmandaris, Vassilis; Lagache, Guilaine; Scott, Douglas

    2012-10-01

    We reproduce the mid-infrared to radio galaxy counts with a new empirical model based on our current understanding of the evolution of main-sequence (MS) and starburst (SB) galaxies. We rely on a simple spectral energy distribution (SED) library based on Herschel observations: a single SED for the MS and another one for SB, getting warmer with redshift. Our model is able to reproduce recent measurements of galaxy counts performed with Herschel, including counts per redshift slice. This agreement demonstrates the power of our 2-Star-Formation Modes (2SFM) decomposition in describing the statistical properties of infrared sources and their evolution with cosmic time. We discuss the relative contribution of MS and SB galaxies to the number counts at various wavelengths and flux densities. We also show that MS galaxies are responsible for a bump in the 1.4 GHz radio counts around 50 {mu}Jy. Material of the model (predictions, SED library, mock catalogs, etc.) is available online.

  10. Multi-Object Spectroscopy with the James Webb Space Telescope’s Near Infrared Spectrograph: Observing Resolved Stellar Populations

    NASA Astrophysics Data System (ADS)

    Gilbert, Karoline; Karakla, Diane M.; Beck, Tracy

    2015-08-01

    The James Webb Space Telescope’s (JWST) Near Infrared Spectrograph (NIRSpec) will provide a multi-object spectroscopy mode through the four Micro-Shutter Arrays (MSAs). Each MSA 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 from 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 for obtaining spectroscopy of individual stars in an external galaxy, and investigate the technical challenges posed by this scenario. We examine the multiplexing capability of the MSA as a function of the possible MSA configuration design choices, and investigate the primary sources of error in velocity measurements and the prospects for minimizing them. We give examples of how this and other use cases are guiding development of the NIRSpec user interfaces, including proposal planning and pipeline calibrations.

  11. Satellite infrared observations of Kuroshio warm-core rings and their application to study of Pacific saury migration

    NASA Astrophysics Data System (ADS)

    Saitoh, Sei-ichi; Kosaka, Sunao; Iisaka, Joji

    1986-11-01

    Satellite infrared observations of Kuroshio warm-core rings (KWCRs), made in the Tohoku area west of 150°E from February 1980 to June 1981, were used to study the effect of ring distributions on the migration routes of the epi-pelagic and migratory fish Pacific saury. Cololabis saira (Brevoort). The movement and mean speed of three KWCRs and a Tsugaru warm current gyre were determined in the study area. KWCRs tended to drift to the north or to the east at a mean speed of 5 cm s -1. This drift speed is similar to that of Gulf Stream warm-core rings, but the drift direction is quite different from the westward drift in the Gulf Stream system. A comparison between distribution of KWCRs and distribution of fish schools suggests that the KWCRs control southward migration routes of Pacific saury through interaction with the surrounding cold waters such as the First and Second Oyashio Intrusions. Satellite infrared monitoring of KWCRs and the surrounding cold waters have proved to be useful for the short period prediction of Pacific saury fishing ground formation.

  12. Exploiting quartz spectral signature for the detection of cloud-affected satellite infrared observations over African desert areas.

    PubMed

    Masiello, Guido; Serio, Carmine; Cuomo, Vincenzo

    2004-04-10

    It is shown that IMG (interferometric monitoring of greenhouse gases) spectra recorded over African and Arabian deserts clearly contain the fingerprint of quartz-rich soils. We illustrate how this spectral signature can be exploited to devise a suitable cloud-detection scheme to identify which infrared observations are affected by clouds. As a by-product, the scheme also allows one to identify the most likely underlying emitting surface type and provides a suitable first guess for the surface emissivity to be used, e.g., for the retrieval of geophysical parameters from high-spectral-resolution infrared radiance from space. The analysis has focused on African deserts because of their intrinsic relevance to numerical weather prediction and Earth's climate. Desert areas, like oceans, are poorly covered by the world meteorological radiosonde network and therefore are geographical regions for which the global coverage capability of satellites soundings is expected to provide better initializations for numerical weather prediction than are now available. Application of the cloud-detection scheme to IMG spectra has been considered, which demonstrates the good performance of the method.

  13. Simultaneous Observation of an Intraband Transition and Distinct Transient Species in the Infrared Region for Perovskite Solar Cells.

    PubMed

    Narra, Sudhakar; Chung, Chih-Chun; Diau, Eric Wei-Guang; Shigeto, Shinsuke

    2016-07-01

    Solar cells based on organometal-halide perovskites such as CH3NH3PbI3 have emerged as a promising next-generation photovoltaic system, but the underlying photophysics and photochemistry remain to be established because of the limited availability of methods to implement the simultaneous and direct measurement of various charge carriers and ions that play a crucial role in the operating device. We used nanosecond time-resolved infrared (IR) spectroscopy to investigate, with high molecular specificity, distinct transient species that are formed in perovskite solar cells after photoexcitation. In CH3NH3PbI3 planar-heterojuction solar cells, we simultaneously observed infrared spectral signatures that are associated with an intraband transition of conduction-band electrons, Fano resonance, and the spiro-OMeTAD cation having an exceptionally short lifetime of 1.0 μs (at ∼1485 cm(-1)). The present results show that the time-resolved IR method offers a unique capability to elucidate these important transients in perovskite solar cells and their dynamic interplay in a comprehensive manner.

  14. Vibrational microspectroscopic identification of powdered traditional medicines: Chemical micromorphology of Poria observed by infrared and Raman microspectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Jian-bo; Sun, Su-qin; Ma, Fang; Zhou, Qun

    2014-07-01

    Microscopic identification using optical microscopes is a simple and effective method to identify powdered traditional medicines made from plants, animals and fungi. Sometimes, the criteria based on physical properties of the microscopic characteristics of drug powder may be ambiguous, which makes the microscopic identification method subjective and empirical to some extent. In this research, the vibrational microspectroscopic identification method is proposed for more explicit discrimination of powdered traditional medicines. The chemical micromorphology, i.e., chemical compositions and related physical morphologies, of the drug powder can be profiled objectively and quantitatively by infrared and Raman microspectroscopy, leading to better understanding about the formation mechanisms of microscopic characteristics and more accurate identification criteria. As an example, the powder of Poria, which is one of the most used traditional Chinese medicines, is studied in this research. Three types of hyphae are classified according to their infrared spectral features in the region from 1200 to 900 cm-1. Different kinds of polysaccharides indicate that these hyphae may be in different stages of the growth. The granular and branched clumps observed by the optical microscope may be formed from the aggregation of the mature hyphae with β-D-glucan reserves. The newfound spherical particles may originate from the exuded droplets in the fresh Poria because they are both composed of α-D-glucan. The results are helpful to understand the development of the hyphae and the formation of active polysaccharides in Poria and to establish accurate microspectroscopic identification criteria.

  15. Experimental observation of multiple dispersive waves emitted by multiple mid-infrared solitons in a birefringence tellurite microstuctured optical fiber.

    PubMed

    Cheng, Tonglei; Tuan, Tong Hoang; Xue, Xiaojei; Liu, Lai; Deng, Dinghuan; Suzuki, Takenobu; Ohishi, Yasutake

    2015-08-10

    We experimentally demonstrate multiple dispersive waves (DWs) emitted by multiple mid-infrared solitons in a birefringence tellurite microstuctured optical fiber (BTMOF). To the best of our knowledge, this is the first demonstration of multiple DWs in the non-silica fibers. By using a pulse of ~80 MHz and ~200 fs emitted from an optical parametric oscillator (OPO) as the pump source, DWs and solitons are investigated on the fast and slow axes of the BTMOF at the pump wavelength of ~1800 nm. With the average pump power increasing from ~200 to 450 mW, the center wavelength of the 1st DW decreases from ~956 to 890 nm, the 2nd DW from ~1039 to 997 nm, the 3rd DW from ~1101 to 1080 nm, and the 4th DW from ~1160 to 1150 nm. Meanwhile, obvious multiple soliton self-frequency shifts (SSFSs) are observed in the mid-infrared region. Furthermore, DWs and solitons at the pump wavelength of ~1400 and 2000 nm are investigated at the average pump power of ~350 mW. PMID:26367917

  16. Simultaneous Observation of an Intraband Transition and Distinct Transient Species in the Infrared Region for Perovskite Solar Cells.

    PubMed

    Narra, Sudhakar; Chung, Chih-Chun; Diau, Eric Wei-Guang; Shigeto, Shinsuke

    2016-07-01

    Solar cells based on organometal-halide perovskites such as CH3NH3PbI3 have emerged as a promising next-generation photovoltaic system, but the underlying photophysics and photochemistry remain to be established because of the limited availability of methods to implement the simultaneous and direct measurement of various charge carriers and ions that play a crucial role in the operating device. We used nanosecond time-resolved infrared (IR) spectroscopy to investigate, with high molecular specificity, distinct transient species that are formed in perovskite solar cells after photoexcitation. In CH3NH3PbI3 planar-heterojuction solar cells, we simultaneously observed infrared spectral signatures that are associated with an intraband transition of conduction-band electrons, Fano resonance, and the spiro-OMeTAD cation having an exceptionally short lifetime of 1.0 μs (at ∼1485 cm(-1)). The present results show that the time-resolved IR method offers a unique capability to elucidate these important transients in perovskite solar cells and their dynamic interplay in a comprehensive manner. PMID:27302315

  17. A solar chromosphere and spicule model based on far-infrared limb observations

    NASA Technical Reports Server (NTRS)

    Braun, D.; Lindsey, C.

    1987-01-01

    Techniques developed for LTE radiative transfer problems in a rough atmosphere were used to compute a model chromosphere containing spicules consistent with high-resolution solar limb observations from 100 microns to 2.6 mm. The model consists of a smooth, plane-parallel temperature minimum region extending from the photosphere to a height of 1000 km and randomly distributed cylindrical spicules above this height. It is found that the observed limb brightness profiles are well fitted by spicules with electron temperatures on the order of 7000 K.

  18. Commercial applications and scientific research requirements for thermal-infrared observations of terrestrial surfaces

    NASA Technical Reports Server (NTRS)

    Goward, Samuel N.; Taranik, James V.; Laporte, Daniel; Putnam, Evelyn S. (Editor)

    1986-01-01

    In the spring of 1986 the EOSAT Company and NASA Headquarters organized a workshop to consider: (1) the potential value of space-acquired multiband thermal remote sensing in terrestrial research and commercial applications, and (2) the scientific and technological requirements for conducting such observations from the LANDSAT platform. The workshop defined the instrument characteristics of three types of sensors that would be needed to expand the use of thermal information for Earth observation and new commercial opportunities. The panels from two disciplines, geology and evapotranspiration/botany, along with the instrument panel, presented their recommendations to the workshop. The findings of these meetings are presented.

  19. Direct observation of surface plasmons in YBCO by attenuated total reflection of light in the infrared

    NASA Astrophysics Data System (ADS)

    Walmsley, D. G.; Smyth, C. C.; Sellai, A.; McCafferty, P. G.; Dawson, P.; Morrow, T.; Graham, W. G.

    1994-02-01

    Surface plasmons have been observed directly in YBCO films in an Otto-geometry attenuated total reflection measurement at a wavelength of 3.392 μm. The laser deposited films are c-axis oriented on an MgO substrate. This observation confirms theoretical deductions from complex dielectric function data. Measured data have been fitted to a theoretical model and are compared with the optical constants determined by Bozovic [1]. The investigations have been extended to films with other orientations to investigate whether material anisotropy is reflected in the results and non-metallic behaviour is found.

  20. Detection of organic compound signatures in infra-red, limb emission spectra observed by the MIPAS-B2 instrument

    NASA Astrophysics Data System (ADS)

    Remedios, J. J.; Allen, G.; Waterfall, A. M.; Oelhaf, H.; Kleinert, A.

    2006-10-01

    Organic compounds play a central role in troposphere chemistry and increasingly are a viable target for remote sensing observations. In this paper, infra-red spectral features of three organic compounds are investigated in thermal emission spectra recorded by a balloon-borne instrument, MIPAS-B2, operating at high spectral resolution. It is demonstrated, for the first time, that PAN and acetone can be detected in infra-red remote sensing spectra of the upper troposphere; detection results are presented at tangent altitudes of 10.4 km and 7.5 km (not acetone). In addition, the results provide the first observation of spectral features of formic acid in thermal emission, as opposed to solar occultation, and confirm that concentrations of this gas are likely to be measurable in the free troposphere, given accurate spectroscopic data. For PAN, two bands are observed centred at 794 cm-1 and 1163 cm-1. For acetone and formic acid, one band has been detected for each so far with band centres at 1218 cm-1 and 1105 cm-1 respectively. Mixing ratios inferred at 10.4 km tangent altitude are 180 pptv and 530 pptv for PAN and acetone respectively, and 200 pptv for formic acid with HITRAN 2000 spectroscopy. Accuracies are on the order of 30 to 50%. The detection technique applied here is verified by examining weak but known signatures of CFC-12 and HCFC-22 in the same spectral regions as those of the organic compounds, with results confirming the quality of both the instrument and the radiative transfer model. The results suggest the possibility of global sensing of the organic compounds studied here which would be a major step forward in verifying and interpreting global tropospheric model calculations.

  1. INFRARED AND RADIO OBSERVATIONS OF A SMALL GROUP OF PROTOSTELLAR OBJECTS IN THE MOLECULAR CORE, L1251-C

    SciTech Connect

    Kim, Jungha; Lee, Jeong-Eun; Choi, Minho; Kang, Miju; Bourke, Tyler L.; II, Neal J. Evans; Francesco, James Di; Cieza, Lucas A.; Dunham, Michael M.

    2015-05-15

    We present a multi-wavelength observational study of a low-mass star-forming region, L1251-C, with observational results at wavelengths from the near-infrared to the millimeter. Spitzer Space Telescope observations confirmed that IRAS 22343+7501 is a small group of protostellar objects. The extended emission in the east–west direction with its intensity peak at the center of L1251A has been detected at 350 and 850 μm with the Caltech Submillimeter Observatory and James Clerk Maxwell telescopes, tracing dense envelope material around L1251A. The single-dish data from the Korean VLBI Network and TRAO telescopes show inconsistencies between the intensity peaks of several molecular emission lines and that of the continuum emission, suggesting complex distributions of molecular abundances around L1251A. The Submillimeter Array interferometer data, however, show intensity peaks of CO 2–1 and {sup 13}CO 2–1 located at the position of IRS 1, which is both the brightest source in the Infrared Array Camera image and the weakest source in the 1.3 mm dust-continuum map. IRS 1 is the strongest candidate for the driving source of the newly detected compact CO 2–1 outflow. Over the entire region (14′ × 14′) of L125l-C, 3 Class I and 16 Class II sources have been detected, including three young stellar objects (YSOs) in L1251A. A comparison between the average projected distance among the 19 YSOs in L1251-C and that among the 3 YSOs in L1251A suggests that L1251-C is an example of low-mass cluster formation where protostellar objects form in a small group.

  2. First results from a high-speed infrared imaging system for the observation of gravity waves in OH airglow

    NASA Astrophysics Data System (ADS)

    Bittner, Michael; Hannawald, Patrick; Schmidt, Carsten; Wüst, Sabine

    2015-04-01

    The OH-airglow-layer is concentrated at a height of about 87 km with a half-width of approximately 3 km. Observing the infrared emissions of the vibrational-rotational excited OH moelcules offers a unique possibility for studying atmospheric dynamics. Especially, atmospheric gravity waves are prominent features in the measurements. Since December 2013 the new imaging system FAIm (Fast Infrared Imager) for the study of smaller-scale features (both in space and time)is operational at the NDMC (Network for the Detection of Mesospheric Change, http://wdc.dlr.de/ndmc)station Oberpfaffenhofen. Covering the brightest OH vibrational bands between 1.3 and 1.7micrometer, the imaging system can acquire 2 frames per second. The field of view is approximately 50 km x 60 km at the mesopause height with a mean spatial resolution of 200 m. More than 370 nights of observation have successfully been performed already. The observations show a large variety of atmospheric waves with horizontal wavelengths down to less than 3km, different directions of propagation and phase velocities varying from nearly 0 m/s (quasi stationary waves) to more than 50 m/s. We present the experimental setup and will show first results. Especially, spatio-temporal sequences of the generation of smaller scale gravity wave fields as well as their turbulent dissipation will be shown. An outlook will be given to planned future simultaneous measurements from different stations in the alpine region in order to achieve some stereoscopic information about gravity wave fields.

  3. SOFIA Mid-infrared Imaging1 and CSO Submillimeter Polarimetry Observations of G034.43+00.24 MM1

    NASA Astrophysics Data System (ADS)

    Jones, T. J.; Gordon, Michael; Shenoy, Dinesh; Gehrz, R. D.; Vaillancourt, John E.; Krejny, M.

    2016-06-01

    We present 11.1 to 37.1 μm imaging observations of the very dense molecular cloud core MM1 in G034.43+00.24 using FORCAST on SOFIA and submillimeter (submm) polarimetry using SHARP on the Caltech Submillimeter Observatory. We find that at the spatial resolution of SOFIA, the point-spread function (PSF) of MM1 is consistent with being a single source, as expected based on millimeter (mm) and submm observations. The spectral energy distributions (SEDs) of MM1 and MM2 have a warm component at the shorter wavelengths not seen in mm and submm SEDs. Examination of H(1.65 μm) stellar polarimetry from the Galactic Plane Infrared Polarization Survey shows that G034 is embedded in an external magnetic field aligned with the Galactic Plane. The SHARP polarimetry at 450 μm shows a magnetic field geometry in the vicinity of MM1 that does not line up with either the Galactic Plane or the mean field direction inferred from the CARMA interferometric polarization map of the central cloud core, but is perpendicular to the long filament in which G034 is embedded. The CARMA polarimetry does show evidence for grain alignment in the central region of the cloud core, and thus does trace the magnetic field geometry near the embedded Class 0 YSO. Based in part on observations made with the NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is jointly operated by the Universities Space Research Association, Inc. (USRA), under NASA contract NAS2-97001, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart.

  4. Infrared and Radio Observations of a Small Group of Protostellar Objects in the Molecular Core, L1251-C

    NASA Astrophysics Data System (ADS)

    Kim, Jungha; Lee, Jeong-Eun; Choi, Minho; Bourke, Tyler L.; Evans, Neal J., II; Di Francesco, James; Cieza, Lucas A.; Dunham, Michael M.; Kang, Miju

    2015-05-01

    We present a multi-wavelength observational study of a low-mass star-forming region, L1251-C, with observational results at wavelengths from the near-infrared to the millimeter. Spitzer Space Telescope observations confirmed that IRAS 22343+7501 is a small group of protostellar objects. The extended emission in the east-west direction with its intensity peak at the center of L1251A has been detected at 350 and 850 μm with the Caltech Submillimeter Observatory and James Clerk Maxwell telescopes, tracing dense envelope material around L1251A. The single-dish data from the Korean VLBI Network and TRAO telescopes show inconsistencies between the intensity peaks of several molecular emission lines and that of the continuum emission, suggesting complex distributions of molecular abundances around L1251A. The Submillimeter Array interferometer data, however, show intensity peaks of CO 2-1 and 13CO 2-1 located at the position of IRS 1, which is both the brightest source in the Infrared Array Camera image and the weakest source in the 1.3 mm dust-continuum map. IRS 1 is the strongest candidate for the driving source of the newly detected compact CO 2-1 outflow. Over the entire region (14‧ × 14‧) of L125l-C, 3 Class I and 16 Class II sources have been detected, including three young stellar objects (YSOs) in L1251A. A comparison between the average projected distance among the 19 YSOs in L1251-C and that among the 3 YSOs in L1251A suggests that L1251-C is an example of low-mass cluster formation where protostellar objects form in a small group.

  5. Infrared Observations of Mars South Polar Residual Cap: When Eating Swiss Cheese - Use a Fork

    NASA Astrophysics Data System (ADS)

    Titus, T. N.; Brown, A. J.; Seelos, F. P.; Murchie, S. L.; Piqueux, S.; Christensen, P. R.; CRISM Team

    2008-03-01

    On the edge of the Mars southern residual cap is a region known as the fork region. This region contains scarps, CO2 Swiss cheese mesas, and a strip of exposed H2O ice 10 km wide. We examine this region using both THEMIS and CRISM observations.

  6. Mid-infrared observations of Io’s volcanism from the ground in 2011 and 2012

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    We report the latest volcanic activity on Io based on our ground-based observations made in 2011 and 2012 using just a 1-m telescope, at 8.9 μm where Io’s thermal radiation dominates solar reflected light seen at shorter wavelengths. A particular result from these observations is that the power we detected from a bright hotspot at the longitude of 282±18°, perhaps Daedalus Patera, was ∼1013 (W) which is comparable to that of Loki Patera, the most powerful volcanic hotspot on Io. We conclude this hotspot is one of the most powerful volcanic hotspots on Io, but its activation is not as frequent as Loki Patera.

  7. Far-infrared photometric observations of the outer planets and satellites with Herschel-PACS

    NASA Astrophysics Data System (ADS)

    Müller, T. G.; Balog, Z.; Nielbock, M.; Moreno, R.; Klaas, U.; Moór, A.; Linz, H.; Feuchtgruber, H.

    2016-04-01

    We present all Herschel-PACS photometer observations of Mars, Saturn, Uranus, Neptune, Callisto, Ganymede, and Titan. All measurements were carefully inspected for quality problems, were reduced in a (semi-)standard way, and were calibrated. The derived flux densities are tied to the standard PACS photometer response calibration, which is based on repeated measurements of five fiducial stars. The overall absolute flux uncertainty is dominated by the estimated 5% model uncertainty of the stellar models in the PACS wavelength range between 60 and 210 μm. A comparison with the corresponding planet and satellite models shows excellent agreement for Uranus, Neptune, and Titan, well within the specified 5%. Callisto is brighter than our model predictions by about 4-8%, Ganymede by about 14-21%. We discuss possible reasons for the model offsets. The measurements of these very bright point-like sources, together with observations of stars and asteroids, demonstrate the high reliability of the PACS photometer observations and the linear behavior of the PACS bolometer source fluxes over more than four orders of magnitude (from mJy levels up to more than 1000 Jy). Our results show the great potential of using the observed solar system targets for cross-calibration purposes with other ground-based, airborne, and space-based instruments and projects. At the same time, the PACS results will lead to improved model solutions for future calibration applications. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  8. Europa's Opposition Surge in the Near-Infrared: Interpreting Disk-Integrated Observations by Cassini VIMS

    NASA Astrophysics Data System (ADS)

    Simonelli, D. P.; Buratti, B. J.

    2003-05-01

    Observations of Europa's opposition surge by Cassini VIMS, presented at last year's DPS, have now been modeled with the commonly used Hapke photometric function. The VIMS dataset emphasizes observations at 16 phase angles from 0.4 to 0.6 deg---the first time the < 1 deg phase ``heart" of Europa's opposition surge has been observed in the near-IR. This dataset also provides a unique opportunity to examine how the surge is affected by changes in wavelength and albedo: at VIMS wavelengths of 0.91, 1.73, and 2.25 microns, the geometric albedo of Europa is 0.81, 0.33, and 0.18 respectively. Despite this factor-of-four albedo range, however, the slope of Europa's phase curve at < 1 deg phase is similar at all three wavelengths (to within error bars) and this common slope is similar to the phase coefficient seen in visible observations of Europa. Two competing models for the opposition surge's physical cause are the Shadow Hiding Opposition Effect (SHOE) and Coherent Backscatter Effect (COBE). Because of sparse VIMS phase coverage, it's not possible to constrain all the surge parameters at once in a Hapke function that has both SHOE and COBE; accordingly, we performed separate Hapke fits for SHOE-only and COBE-only surges. At 2.25 microns, where VIMS data are somewhat noisy, both types of surges can mimic the slope of the VIMS phase curve at < 1 deg phase. At 0.91 and 1.73 microns, however---where VIMS data are ``cleaner"---COBE does a noticeably poorer job than SHOE of matching the VIMS phase coefficient at < 1 deg phase; in particular, the best COBE fit insists on having a steeper phase-curve slope than the data. This suggests---without being conclusive---that COBE is less likely than SHOE to be the cause of Europa's near-IR opposition surge.

  9. Ionization structure of the Orion Nebula - infrared line observations and models

    SciTech Connect

    Simpson, J.P.; Rubin, R.H.; Erickson, E.F.; Haas, M.R.

    1986-12-01

    Observations of the forbidden O III 52 and 88 microns lines and the forbidden N III 57 microns line have been made at six positions and the forbidden Ne III 36 microns line at four positions in the Orion Nebula to probe its ionization structure. The wavelength of the forbidden Ne III line was measured to be 36.009-36.017 microns. Electron densities and abundance ratios of N(++)/O(++) have been calculated and compared to other radio and optical observations. Detailed one-component and two-component (bar plus halo) spherical models were calculated for exciting stars with effective temperatures of 37,000-40,000 K and log g = 4.0 and 4.5. Both the new IR observations and the visible line measurements of oxygen and nitrogen require Teff of no more than 37,000 K. However, the doubly ionized neon requires a model with Teff of at least 39,000 K, which is more consistent with that inferred from the radio flux or spectral type. These differences in Teff are not due to effects of dust on the stellar radiation field but are probably due to inaccuracies in the assumed stellar spectrum. Neon and nitrogen are approximately solar, but oxygen is half-solar in abundance. From the IR O(++) lines, it is concluded that the ionization bar results from an increase in column depth rather than from a local density enhancement. 54 references.

  10. The ionization structure of the Orion Nebula - Infrared line observations and models

    NASA Technical Reports Server (NTRS)

    Simpson, J. P.; Rubin, R. H.; Erickson, E. F.; Haas, M. R.

    1986-01-01

    Observations of the forbidden O III 52 and 88 microns lines and the forbidden N III 57 microns line have been made at six positions and the forbidden Ne III 36 microns line at four positions in the Orion Nebula to probe its ionization structure. The wavelength of the forbidden Ne III line was measured to be 36.009-36.017 microns. Electron densities and abundance ratios of N(++)/O(++) have been calculated and compared to other radio and optical observations. Detailed one-component and two-component (bar plus halo) spherical models were calculated for exciting stars with effective temperatures of 37,000-40,000 K and log g = 4.0 and 4.5. Both the new IR observations and the visible line measurements of oxygen and nitrogen require Teff of no more than 37,000 K. However, the doubly ionized neon requires a model with Teff of at least 39,000 K, which is more consistent with that inferred from the radio flux or spectral type. These differences in Teff are not due to effects of dust on the stellar radiation field but are probably due to inaccuracies in the assumed stellar spectrum. Neon and nitrogen are approximately solar, but oxygen is half-solar in abundance. From the IR O(++) lines, it is concluded that the ionization bar results from an increase in column depth rather than from a local density enhancement.

  11. A Mid-latitude Cloud Eruption on Titan Observed by the Cassini Visual Infrared Mapping Spectrometer (VIMS) in July 2007

    NASA Astrophysics Data System (ADS)

    Buratti, B. J.; Pitman, K. M.; Baines, K.; Sotin, C.; Brown, R. H.; Clark, R. N.; Nicholson, P. D.; Griffith, C. A.; Le Mouelic, S.; Momary, T.

    2007-12-01

    Mid-latitude clouds on Titan have been monitored by the Cassini spacecraft since they were reported by ground- based observers (Roe et al. 2005, Ap. J. 618, L49). The Cassini Visual Infrared Mapping Spectrometer (VIMS) is especially suited to detecting and mapping these clouds because its wavelength range of 0.4-5.1 microns covers several key methane cloud filters. These clouds may be the result of atmospheric upwelling on Titan (Griffith et al. 2000 Science 290, p. 509; Rannou et al. 2006 Science 311, p. 201), or they may start as plumes coming from active geologic features on Titan (Roe et al. 2005, Science 310, p. 477). Mid-latitude clouds were observed in the early part of the nominal mission (Dec. 2004 and early 2005), but they had disappeared until a large cloud system was observed in summer 2006, in the 0-90 degrees W longitude mid-latitude regions of Titan. A new group of clouds was observed during the two flybys of July 2007, which dwarfs the previous mid-latitude system. These clouds originate in a region centered on ~200 W longitude and ~48 S latitude. Monitoring of mid-latitude clouds will show whether their timescales for formation are compatible with climate models for Titan's atmosphere. If mid-latitude clouds are the result of active geologic processes, there appears to be more than one source on Titan's surface. Work funded by NASA.

  12. Wide-field infrared survey explorer observations of young stellar objects in the Lynds 1509 dark cloud in Auriga

    SciTech Connect

    Liu, Wilson M.; McCollum, Bruce; Fajardo-Acosta, Sergio; Padgett, Deborah L.; Terebey, Susan; Angione, John; Rebull, Luisa M.; Leisawitz, David

    2014-06-01

    The Wide-Field Infrared Survey Explorer (WISE) has uncovered a striking cluster of young stellar object (YSO) candidates associated with the L1509 dark cloud in Auriga. The WISE observations, at 3.4 μm, 4.6 μm, 12 μm, and 22 μm, show a number of objects with colors consistent with YSOs, and their spectral energy distributions suggest the presence of circumstellar dust emission, including numerous Class I, flat spectrum, and Class II objects. In general, the YSOs in L1509 are much more tightly clustered than YSOs in other dark clouds in the Taurus-Auriga star forming region, with Class I and flat spectrum objects confined to the densest aggregates, and Class II objects more sparsely distributed. We estimate a most probable distance of 485-700 pc, and possibly as far as the previously estimated distance of 2 kpc.

  13. Experimental observation of mid-infrared higher-order soliton fission in a tapered tellurite microstructured optical fiber

    NASA Astrophysics Data System (ADS)

    Cheng, Tonglei; Xue, Xiaojie; Liu, Lai; Suzuki, Takenobu; Ohishi, Yasutake

    2016-06-01

    The evolution of mid-infrared (MIR) higher-order soliton fission in a tapered tellurite microstructured optical fiber (TMOF) is experimentally investigated. From ∼30 to 80 mW, the redshift of the first fundamental soliton is obvious. From ∼80 to 120 mW, two fundamental solitons are obtained by the fission of higher-order solitons. The redshift of the first fundamental soliton almost stops because the increased pump power is preferentially distributed to the second fundamental soliton. From ∼120 to 180 mW, an obvious redshift of the first fundamental soliton is observed again, and a third fundamental soliton is obtained at ∼180 mW. The evolution of each soliton is determined by the power distribution, which is, to the best of our knowledge, reported for the first time.

  14. Wide-Field Infrared Survey Explorer Observations of Young Stellar Objects in the Lynds 1509 Dark Cloud in Auriga

    NASA Technical Reports Server (NTRS)

    Liu, Wilson M.; Padgett, Deborah L.; Terebey, Susan; Angione, John; Rebull, Luisa M.; McCollum, Bruce; Fajardo-Acosta, Sergio; Leisawitz, David

    2015-01-01

    The Wide-Field Infrared Survey Explorer (WISE) has uncovered a striking cluster of young stellar object (YSO) candidates associated with the L1509 dark cloud in Auriga. The WISE observations, at 3.4, 4.6, 12, and 22 microns, show a number of objects with colors consistent with YSOs, and their spectral energy distributions suggest the presence of circumstellar dust emission, including numerous Class I, flat spectrum, and Class II objects. In general, the YSOs in L1509 are much more tightly clustered than YSOs in other dark clouds in the Taurus-Auriga star forming region, with Class I and flat spectrum objects confined to the densest aggregates, and Class II objects more sparsely distributed. We estimate a most probable distance of 485-700 pc, and possibly as far as the previously estimated distance of 2 kpc.

  15. Characterisation of dust aerosols in the infrared from IASI and comparison with PARASOL, MODIS, MISR, CALIOP, and AERONET observations

    NASA Astrophysics Data System (ADS)

    Peyridieu, S.; Chédin, A.; Capelle, V.; Tsamalis, C.; Pierangelo, C.; Armante, R.; Crevoisier, C.; Crépeau, L.; Siméon, M.; Ducos, F.; Scott, N. A.

    2013-06-01

    Infrared Atmospheric Sounder Interferometer (IASI) observations covering the period from July 2007 to December 2011 are interpreted in terms of monthly mean, 1°×1°, 10 μm dust Aerosol Optical Depth (AOD), mean altitude and coarse mode effective radius. The geographical study area includes the northern tropical Atlantic and the northwest Arabian Sea, both characterised by strong, regular dust events. The method developed relies on the construction of Look-Up-Tables computed for a large selection of atmospheric situations and observing conditions. At a regional scale, a good agreement is found between IASI-retrieved 10 μm AOD and total visible optical depth at 550 nm from either the Moderate resolution Imaging Spectroradiometer (MODIS/Aqua or Terra), or the Multi-angle Imaging SpectroRadiometer (MISR), or the Polarization and Anisotropy of Reflectances for Atmospheric Science coupled with Observations from a Lidar (PARASOL). Taking into account the ratio existing between infrared and visible AODs, the diversity between the different 550 nm AODs is similar to the difference between these and the IASI AODs. The infrared AOD to visible AOD ratio, partly reflecting the varying distribution of the dust layer between the dust coarse mode particles seen by IASI, and the fine mode seen by the other instruments, is found to vary with the region observed with values close to already published values. Comparisons between the climatologies of the 10 μm IASI AOD and of the PARASOL non-spherical coarse mode AOD at 865 nm, both expected to be representative of the dust coarse mode, lead to conclusions differing according to the region considered. These differences are discussed in the light of the MODIS Angström exponent (865-550 nm). At local scale, around six Aerosol Robotic Network (AERONET) sites, close or far from the dust sources, a similar satisfactory agreement is found between IASI and the visible AODs and the differences between these products are shown and

  16. Characterization of dust aerosols in the infrared from IASI and comparison with PARASOL, MODIS, MISR, CALIOP, and AERONET observations

    NASA Astrophysics Data System (ADS)

    Peyridieu, S.; Chédin, A.; Capelle, V.; Tsamalis, C.; Pierangelo, C.; Armante, R.; Crevoisier, C.; Crépeau, L.; Siméon, M.; Ducos, F.; Scott, N. A.

    2012-09-01

    Infrared Atmospheric Sounder Interferometer (IASI) observations covering the period from July 2007 to December 2011 are interpreted in terms of monthly mean, 1°×1°, 10 μm dust Aerosol Optical Depth (AOD), mean altitude and coarse mode effective radius. The geographical study area includes the northern tropical Atlantic and the north-west Arabian Sea, both characterized by strong, regular dust events. The method developed relies on the construction of Look-Up-Tables computed for a large selection of atmospheric situations and observing conditions. At regional scale, a good agreement is found between IASI-retrieved 10 μm AOD and total visible optical depth at 550 nm from either the Moderate resolution Imaging Spectroradiometer (MODIS/Aqua or Terra), or the Multi-angle Imaging SpectroRadiometer (MISR), or the Polarization and Anisotropy of Reflectances for Atmospheric Science coupled with Observations from a Lidar (PARASOL). Taking into account the ratio existing between infrared and visible AODs, the diversity between the different 550 nm AODs is similar to the difference between these and the IASI AODs. The infrared AOD to visible AOD ratio, partly reflecting the varying distribution of the dust layer between the dust coarse mode particles seen by IASI, and the fine mode seen by the other instruments, is found to vary with the region observed with values close to already published values. Comparisons between the climatologies of the 10 μm IASI AOD and of the PARASOL non-spherical coarse mode AOD at 865 nm, both expected to be representative of the dust coarse mode, lead to conclusions differing according to the region considered. These differences are discussed in the light of the MODIS Angström exponent (865-550 nm). At local scale, around six Aerosol Robotic Network (AERONET) sites, close or far from the dust sources, a similar satisfactory agreement is found between IASI and the visible AODs and the differences between these products are shown and analysed

  17. Near-infrared polarimetric adaptive optics observations of NGC 1068: a torus created by a hydromagnetic outflow wind

    NASA Astrophysics Data System (ADS)

    Lopez-Rodriguez, E.; Packham, C.; Jones, T. J.; Nikutta, R.; McMaster, L.; Mason, R. E.; Elvis, M.; Shenoy, D.; Alonso-Herrero, A.; Ramírez, E.; González Martín, O.; Hönig, S. F.; Levenson, N. A.; Ramos Almeida, C.; Perlman, E.

    2015-09-01

    We present J' and K' imaging linear polarimetric adaptive optics observations of NGC 1068 using MMT-Pol on the 6.5-m MMT. These observations allow us to study the torus from a magnetohydrodynamical (MHD) framework. In a 0.5 arcsec (30 pc) aperture at K', we find that polarization arising from the passage of radiation from the inner edge of the torus through magnetically aligned dust grains in the clumps is the dominant polarization mechanism, with an intrinsic polarization of 7.0 ± 2.2 per cent. This result yields a torus magnetic field strength in the range of 4-82 mG through paramagnetic alignment, and 139^{+11}_{-20} mG through the Chandrasekhar-Fermi method. The measured position angle (P.A.) of polarization at K' is found to be similar to the P.A. of the obscuring dusty component at few parsec scales using infrared interferometric techniques. We show that the constant component of the magnetic field is responsible for the alignment of the dust grains, and aligned with the torus axis on to the plane of the sky. Adopting this magnetic field configuration and the physical conditions of the clumps in the MHD outflow wind model, we estimate a mass outflow rate ≤0.17 M⊙ yr-1 at 0.4 pc from the central engine for those clumps showing near-infrared dichroism. The models used were able to create the torus in a time-scale of ≥105 yr with a rotational velocity of ≤1228 km s-1 at 0.4 pc. We conclude that the evolution, morphology and kinematics of the torus in NGC 1068 can be explained within a MHD framework.

  18. Wisps in the Galactic center: Near-infrared triggered observations of the radio source Sgr A* at 43 GHz

    NASA Astrophysics Data System (ADS)

    Rauch, C.; Ros, E.; Krichbaum, T. P.; Eckart, A.; Zensus, J. A.; Shahzamanian, B.; Mužić, K.

    2016-03-01

    Context. The compact radio and near-infrared (NIR) source Sagittarius A* (Sgr A*) associated with the supermassive black hole in the Galactic center was observed at 7 mm in the context of a NIR triggered global Very Long Baseline Array (VLBA) campaign. Aims: Sgr A* shows variable flux densities ranging from radio through X-rays. These variations sometimes appear in spontaneous outbursts that are referred to as flares. Multi-frequency observations of Sgr A* provide access to easily observable parameters that can test the currently accepted models that try to explain these intensity outbursts. Methods: On May 16-18, 2012 Sgr A* has been observed with the VLBA at 7 mm (43 GHz) for 6 h each day during a global multi-wavelength campaign. These observations were triggered by a NIR flare observed at the Very Large Telescope (VLT). Accurate flux densities and source morphologies were acquired. Results: The total 7 mm flux of Sgr A* shows only minor variations during its quiescent states on a daily basis of 0.06 Jy. An observed NIR flare on May 17 was followed ~4.5 h later by an increase in flux density of 0.22 Jy at 43 GHz. This agrees well with the expected time delay of events that are casually connected by adiabatic expansion. Shortly before the peak of the radio flare, Sgr A* developed a secondary radio off-core feature at 1.5 mas toward the southeast. Even though the closure phases are too noisy to place actual constraints on this feature, a component at this scale together with a time delay of 4.5 ± 0.5 h between the NIR and radio flare provide evidence for an adiabatically expanding jet feature.

  19. The Observation of Fault Finiteness and Rapid Velocity Variation in Pnl Waveforms for the Mw 6.5, San Simeon, California Earthquake

    NASA Astrophysics Data System (ADS)

    Konca, A. O.; Ji, C.; Helmberger, D. V.

    2004-12-01

    We observed the effect of the fault finiteness in the Pnl waveforms from regional distances (4° to 12° ) for the Mw6.5 San Simeon Earthquake on 22 December 2003. We aimed to include more of the high frequencies (2 seconds and longer periods) than the studies that use regional data for focal solutions (5 to 8 seconds and longer periods). We calculated 1-D synthetic seismograms for the Pn_l portion for both a point source, and a finite fault solution. The comparison of the point source and finite fault waveforms with data show that the first several seconds of the point source synthetics have considerably higher amplitude than the data, while finite fault does not have a similar problem. This can be explained by reversely polarized depth phases overlapping with the P waves from the later portion of the fault, and causing smaller amplitudes for the beginning portion of the seismogram. This is clearly a finite fault phenomenon; therefore, can not be explained by point source calculations. Moreover, the point source synthetics, which are calculated with a focal solution from a long period regional inversion, are overestimating the amplitude by three to four times relative to the data amplitude, while finite fault waveforms have the similar amplitudes to the data. Hence, a moment estimation based only on the point source solution of the regional data could have been wrong by half of magnitude. We have also calculated the shifts of synthetics relative to data to fit the seismograms. Our results reveal that the paths from Central California to the south are faster than to the paths to the east and north. The P wave arrival to the TUC station in Arizona is 4 seconds earlier than the predicted Southern California model, while most stations to the east are delayed around 1 second. The observed higher uppermost mantle velocities to the south are consistent with some recent tomographic models. Synthetics generated with these models significantly improves the fits and the

  20. Variability of the Venus condensational clouds from analysis of VIRTIS-M-IR observations of the near-infrared spectral windows

    NASA Astrophysics Data System (ADS)

    McGouldrick, Kevin; Tsang, Constantine C. C.

    2015-11-01

    The Medium Resolution, Infrared wavelength channel of the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS-M-IR) on the Venus Express spacecraft observed the atmosphere and surface of Venus for 921 orbits following orbit insertion in April 2006 until the failure of the cooling unit in October 2008. The clouds of Venus were long thought to be a uniform sort of perpetual stratocumulus, but near infrared observations by fly-by spacecraft such as Galileo (Near Infrared Mapping Spectrometer) and Cassini (Visible and Infrared Mapping Spectrometer), as well as ground-based observations, indicated a great deal of temporal and spatial inhomogeneity. The nearly three-year lifetime of the VIRTIS-M-IR instrument on Venus Express presents an unprecedented opportunity to quantify these spatial and temporal variations of the Venus clouds. Here, we present the results of an initial quantification of the overall tendencies of the Venus clouds, as measured by variations in the near infrared spectral windows located between wavelengths of 1.0 µm and 2.6 µm. In a companion submission, we also investigate the variations of carbon monoxide and other trace species quantifiable in these data (Tsang and McGouldrick 2015). This work is supported by the Planetary Mission Data Analysis Program, Grant Number NNX14AP94G.

  1. Evidence for magmatic evolution and diversity on Mars from infrared observations

    USGS Publications Warehouse

    Christensen, P.R.; McSween, H.Y.; Bandfield, J.L.; Ruff, S.W.; Rogers, A.D.; Hamilton, V.E.; Gorelick, N.; Wyatt, M.B.; Jakosky, B.M.; Kieffer, H.H.; Malin, M.C.; Moersch, J.E.

    2005-01-01

    Compositional mapping of Mars at the 100-metre scale with the Mars Odyssey Thermal Emission Imaging System (THEMIS) has revealed a wide diversity of igneous materials. Volcanic evolution produced compositions from low-silica basalts to high-silica dacite in the Syrtis Major caldera. The existence of dacite demonstrates that highly evolved lavas have been produced, at least locally, by magma evolution through fractional crystallization. Olivine basalts are observed on crater floors and in layers exposed in canyon walls up to 4.5 km beneath the surface. This vertical distribution suggests that olivine-rich lavas were emplaced at various times throughout the formation of the upper crust, with their growing inventory suggesting that such ultramafic (picritic) basalts may be relatively common. Quartz-bearing granitoid rocks have also been discovered, demonstrating that extreme differentiation has occurred. These observations show that the martian crust, while dominated by basalt, contains a diversity of igneous materials whose range in composition from picritic basalts to granitoids rivals that found on the Earth.

  2. Evidence for magmatic evolution and diversity on Mars from infrared observations.

    PubMed

    Christensen, P R; McSween, H Y; Bandfield, J L; Ruff, S W; Rogers, A D; Hamilton, V E; Gorelick, N; Wyatt, M B; Jakosky, B M; Kieffer, H H; Malin, M C; Moersch, J E

    2005-07-28

    Compositional mapping of Mars at the 100-metre scale with the Mars Odyssey Thermal Emission Imaging System (THEMIS) has revealed a wide diversity of igneous materials. Volcanic evolution produced compositions from low-silica basalts to high-silica dacite in the Syrtis Major caldera. The existence of dacite demonstrates that highly evolved lavas have been produced, at least locally, by magma evolution through fractional crystallization. Olivine basalts are observed on crater floors and in layers exposed in canyon walls up to 4.5 km beneath the surface. This vertical distribution suggests that olivine-rich lavas were emplaced at various times throughout the formation of the upper crust, with their growing inventory suggesting that such ultramafic (picritic) basalts may be relatively common. Quartz-bearing granitoid rocks have also been discovered, demonstrating that extreme differentiation has occurred. These observations show that the martian crust, while dominated by basalt, contains a diversity of igneous materials whose range in composition from picritic basalts to granitoids rivals that found on the Earth.

  3. Infrared-excess Source DSO/G2 Near the Galactic Center: Theory vs. Observations

    NASA Astrophysics Data System (ADS)

    Zajacek, Michal; Eckart, Andreas; Peissker, Florian; Karssen, Grischa D.; Karas, Vladimir

    2015-12-01

    Based on the monitoring of the Dusty S-cluster Object (DSO/G2) during its closest approach to the Galactic Center supermassive black hole in 2014 and 2015 with ESO VLT/SINFONI, we further explore the model of a young, accreting star to explain observed spectral and morphological features. The stellar scenario is supported by our findings, i.e., ionized-hydrogen emission from the DSO that remains spatially compact before and after the peribothron passage. The detection of DSO/G2 object as a compact single-peak emission-line source is not consistent with the original hypothesis of a core-less cloud that is necessarily tidally stretched, hence producing a double-peak emission line profile around the pericentre passage. This strengthens the evidence that the DSO/G2 source is a dust-enshrouded young star that appears to be in an accretion phase. The infall of material from the circumstellar disc onto the stellar surface can contribute significantly to the emission of Brγ line as well as the observed large line width of the order of 10 angstrom.

  4. Observations of far-infrared transitions between excited states of OH

    NASA Technical Reports Server (NTRS)

    Viscuso, P. J.; Stacey, G. J.; Harwit, M.; Haas, M. R.; Erickson, E. F.; Duffy, P. B.

    1985-01-01

    In observations of the Kleinmann-Low Nebula were detected of Orion 84.42 and 84.60 micron transitions between the P-2 sub 3/2 and Pi-2 sub 3/2 (J = 5/2) levels of OH with respective fluxes of 1.0 + or - 0.3 to the minus 17th power and 1.4 + or - 0.4 x 10 to the minus 17th power W cm/sq. When compared to 119 micron flux levels of OH and 153 micron flux levels of these radicals by Viscuso, these results suggest appreciable self-absorption of OH line radiation within the Nebula. It is probable that the CO emission due to the J = 31 yields 30 rotational transition at 84.411 micron makes a substantial contribution to the observed 84.42 micron flux, and that it also is at least partially absorbed at the 84.42 micron OH transition frequency. The 88.55 and 88.78 micron (J = 9/2 to 7/2) transitions of CH also were sought, but yielded only to upper limits of 3 x 10 to the minus 18th power W /sq cm each. A search of W3-IRS5 yields upper limits to the 84.42 micron OH and 87.19 micron CO (J = 30 to 29) transitions of 2 x 10 minus 18th power W cm/2.

  5. Evidence for magmatic evolution and diversity on Mars from infrared observations.

    PubMed

    Christensen, P R; McSween, H Y; Bandfield, J L; Ruff, S W; Rogers, A D; Hamilton, V E; Gorelick, N; Wyatt, M B; Jakosky, B M; Kieffer, H H; Malin, M C; Moersch, J E

    2005-07-28

    Compositional mapping of Mars at the 100-metre scale with the Mars Odyssey Thermal Emission Imaging System (THEMIS) has revealed a wide diversity of igneous materials. Volcanic evolution produced compositions from low-silica basalts to high-silica dacite in the Syrtis Major caldera. The existence of dacite demonstrates that highly evolved lavas have been produced, at least locally, by magma evolution through fractional crystallization. Olivine basalts are observed on crater floors and in layers exposed in canyon walls up to 4.5 km beneath the surface. This vertical distribution suggests that olivine-rich lavas were emplaced at various times throughout the formation of the upper crust, with their growing inventory suggesting that such ultramafic (picritic) basalts may be relatively common. Quartz-bearing granitoid rocks have also been discovered, demonstrating that extreme differentiation has occurred. These observations show that the martian crust, while dominated by basalt, contains a diversity of igneous materials whose range in composition from picritic basalts to granitoids rivals that found on the Earth. PMID:16007077

  6. Magnetic Helicity Estimations in Models and Observations of the Solar Magnetic Field. Part I: Finite Volume Methods

    NASA Astrophysics Data System (ADS)

    Valori, Gherardo; Pariat, Etienne; Anfinogentov, Sergey; Chen, Feng; Georgoulis, Manolis K.; Guo, Yang; Liu, Yang; Moraitis, Kostas; Thalmann, Julia K.; Yang, Shangbin

    2016-10-01

    Magnetic helicity is a conserved quantity of ideal magneto-hydrodynamics characterized by an inverse turbulent cascade. Accordingly, it is often invoked as one of the basic physical quantities driving the generation and structuring of magnetic fields in a variety of astrophysical and laboratory plasmas. We provide here the first systematic comparison of six existing methods for the estimation of the helicity of magnetic fields known in a finite volume. All such methods are reviewed, benchmarked, and compared with each other, and specifically tested for accuracy and sensitivity to errors. To that purpose, we consider four groups of numerical tests, ranging from solutions of the three-dimensional, force-free equilibrium, to magneto-hydrodynamical numerical simulations. Almost all methods are found to produce the same value of magnetic helicity within few percent in all tests. In the more solar-relevant and realistic of the tests employed here, the simulation of an eruptive flux rope, the spread in the computed values obtained by all but one method is only 3 %, indicating the reliability and mutual consistency of such methods in appropriate parameter ranges. However, methods show differences in the sensitivity to numerical resolution and to errors in the solenoidal property of the input fields. In addition to finite volume methods, we also briefly discuss a method that estimates helicity from the field lines' twist, and one that exploits the field's value at one boundary and a coronal minimal connectivity instead of a pre-defined three-dimensional magnetic-field solution.

  7. Galaxy evolution and large-scale structure in the far-infrared. I - IRAS pointed observations

    NASA Technical Reports Server (NTRS)

    Lonsdale, Carol J.; Hacking, Perry B.

    1989-01-01

    Redshifts for 66 galaxies were obtained from a sample of 93 60-micron sources detected serendipitously in 22 IRAS deep pointed observations, covering a total area of 18.4 sq deg. The flux density limit of this survey is 150 mJy, 4 times fainter than the IRAS Point Source Catalog (PSC). The luminosity function is similar in shape with those previously published for samples selected from the PSC, with a median redshift of 0.048 for the fainter sample, but shifted to higher space densities. There is evidence that some of the excess number counts in the deeper sample can be explained in terms of a large-scale density enhancement beyond the Pavo-Indus supercluster. In addition, the faintest counts in the new sample confirm the result of Hacking et al. (1989) that faint IRAS 60-micron source counts lie significantly in excess of an extrapolation of the PSC counts assuming no luminosity or density evolution.

  8. Observations of the infrared radiation from the nuclei of NGC 1068 and NGC 4151

    NASA Technical Reports Server (NTRS)

    Stein, W. A.; Gillett, F. C.; Merrill, K. M.

    1974-01-01

    Data resulting from monitoring the flux of radiation at 11 microns from NGC 1068 and NGC 4151 are presented. There is some evidence for changes of flux of 50% on a time scale of approximately 100 days from NGC 4151. This evidence is suggestive but not compelling. Limits are set on the possible change of the 11-micron flux from NGC 1068. The energy distribution of radiation from NGC 1068 between 8 and 13 microns has been shown to have no spectral features within the accuracy and resolution of our measurement. This is in contrast to energy distributions observed from galactic sources in which the source of energy is generally interpreted as thermal reradiation from grains.

  9. Infrared observations of low-mass star formation in Orion - HH objects

    NASA Technical Reports Server (NTRS)

    Harvey, P. M.; Wilking, B. A.; Cohen, M.

    1982-01-01

    The results of a preliminary analysis of IR data on Herbig-Haro objects in the Orion nebula are reported. The observations were made with the high angular resolution IR photometry equipment on the NASA Kuiper Airborne Observatory and the NASA facility on Mauna Kea, HI. Data were taken in the 1-200 microns region with 40, 6, and 8 arcsec resolution. Attention was focused on NGC 1999 (HH1-3) and M78 (HH24-25) and the determination of absolute luminosities of the exciting stars. Measurements were also made of the IR energy distribution in the thermally emitting dust clouds and the point sources. Herbig-Haro objects featured compact and far IR sizes and large visual extinction, in addition to a steeply rising energy distribution up to 50-100 microns, where the luminosity emitted was concentrated.

  10. Galaxy evolution and large-scale structure in the far-infrared. I - IRAS pointed observations

    NASA Astrophysics Data System (ADS)

    Lonsdale, Carol J.; Hacking, Perry B.

    1989-04-01

    Redshifts for 66 galaxies were obtained from a sample of 93 60-micron sources detected serendipitously in 22 IRAS deep pointed observations, covering a total area of 18.4 sq deg. The flux density limit of this survey is 150 mJy, 4 times fainter than the IRAS Point Source Catalog (PSC). The luminosity function is similar in shape with those previously published for samples selected from the PSC, with a median redshift of 0.048 for the fainter sample, but shifted to higher space densities. There is evidence that some of the excess number counts in the deeper sample can be explained in terms of a large-scale density enhancement beyond the Pavo-Indus supercluster. In addition, the faintest counts in the new sample confirm the result of Hacking et al. (1989) that faint IRAS 60-micron source counts lie significantly in excess of an extrapolation of the PSC counts assuming no luminosity or density evolution.

  11. An Explanation for the Observed Spectral Contrast Reduction Between Field and Laboratory Infrared Measurements of Soils

    NASA Astrophysics Data System (ADS)

    Johnson, J. R.; Lucey, P. G.; Horton, K. A.; Williams, T.; Winter, E. M.; Stocker, A. D.

    1996-03-01

    Comparison of emission spectra (7-14 m) of pristine soils in the field with bidirectional reflectance spectra of soils obtained in the laboratory shows that laboratory spectra tend to have less contrast than field spectra. We investigated this phenomenon by measuring emission spectra of both pristine (in situ) and sampled soils (prepared as if for transport to the laboratory). The sampled soils had much less spectral contrast than the pristine soils in the reststrahlen region near 9 m. We hypothesize that this effect is due to a difference in grainsize distribution of the optically active layer (i.e., fine particle coatings). This concept was proposed by Salisbury et al. to explain their observations that soils washed free of small particles adhering to larger grains exhibited greater spectral contrast than unwashed soils. Unrecognized, this phenomenon could influence interpretations of remote sensing data since it is a common practice to use spectra of materials obtained in the laboratory to interpret spectra obtained remotely.

  12. Vertical profiling of methane and carbon dioxide using high resolution near-infrared heterodyne spectroscopic observations

    NASA Astrophysics Data System (ADS)

    Rodin, Alexander; Klimchuk, Artem; Churbanov, Dmitry; Pereslavtseva, Anastasia; Spiridonov, Maxim; Nadezhdinskyi, Alexander

    2014-05-01

    We present new method of monitoring greenhouse gases using spectroscopic observations of solar radiation passed through the atmosphere with spectral resolution ΛvδΛ up to 108. Such a high resolution is achieved by heterodyne technique and allows to retrieve full information about spectral line shape which, in turn, is used to distinguish contribution of different atmospheric layers to the resulting absorption. Weak absorption line at 6056.5 cm-1 was selected for CO2 measurements and a quartet of lines centered at 6057 cm-1for CH4. The instrument setup includes Sun tracker with a microtelescope and chopper, diode DFB laser used as a local oscillator, a bundle of single mode optical fibers that provides medium for radiation transfer and beam coupling, reference cell with depressurized methane for LO frequency stabilization, and Fabry-Perot etalon for LO frequency calibration. A commercial p-i-n diode with squared detector replaces a mixer and IF spectrometer, providing measurement of heterodyne beating within a bandpass of few MHz, which determines the effective spectral resolution of the instrument. Spectral coverage within narrow range (about 1 cm-1) is provided by ramping the LO frequency based on feedback from the reference channel. Observations of Sun in the Moscow region have resulted for the first time in measurements of the atmospheric transmission near 1.65 μm with sub-Doppler spectral resolution. In order to retrieve vertical profiles of methane and carbon dioxide we developed the inversion algorithm implementing Tikhonov regularization approach. With measured transmission having S/N ratio of 100 or higher, the uncertainty of CH4 profile is about 10 ppb, with the uncertainty of CO2 profile at 1 ppm. This techniques is promising an affordable opportunity or widespread monitoring of greenhouse gases and may be implemented on existing ground-based stations. This work has been supported by the grant of Russian Ministry of education and science #11.G34.31.0074

  13. CLOUD AND HAZE IN THE WINTER POLAR REGION OF TITAN OBSERVED WITH VISUAL AND INFRARED MAPPING SPECTROMETER ON BOARD CASSINI

    SciTech Connect

    Rannou, P.; Le Mouelic, S.; Sotin, C.; Brown, R. H.

    2012-03-20

    A large cloud in the north polar region of Titan was first observed by the Visual and Infrared Mapping Spectrometer (VIMS) in 2005 and then in 2006. This cloud, confined beyond the latitude 62 Degree-Sign N, is surrounded by a mixture of aerosol and mist probably lying in the low stratosphere and troposphere. Subsequent images of this region of Titan show a gradual vanishing of this cloud which was reported previously. In this paper, we characterize the physical properties of this cloud, haze, and mist as well as their time evolutions. We note several details on the images such as a secondary cloud above the main cloud and latitudes beyond 70 Degree-Sign N. We also show that the cloud disappearance leaves the polar region poorly loaded in aerosols, yielding an annular zone of aerosols between 50 Degree-Sign N and 65 Degree-Sign N. Our analysis suggests that this structure observed by VIMS in the near-IR is an annular structure observed by ISS on board Voyager one Titan year ago in 1980.

  14. Extratympanic observation of middle ear structure using a refractive index matching material (glycerol) and an infrared camera

    NASA Astrophysics Data System (ADS)

    Kong, Soo-Keun; Chon, Kyong-Myong; Goh, Eui-Kyung; Lee, Il-Woo; Wang, Soo-Geun

    2014-05-01

    High-resolution computed tomography has been used mainly in the diagnosis of middle ear disease, such as high-jugular bulb, congenital cholesteatoma, and ossicular disruption. However, certain diagnoses are confirmed through exploratory tympanotomy. There are few noninvasive methods available to observe the middle ear. The purpose of this study was to investigate the effect of glycerol as a refractive index matching material and an infrared (IR) camera system for extratympanic observation. 30% glycerol was used as a refractive index matching material in five fresh cadavers. Each material was divided into four subgroups; GN (glycerol no) group, GO (glycerol out) group, GI (glycerol in) group, and GB (glycerol both) group. A printed letter and middle ear structures on the inside tympanic membrane were observed using a visible and IR ray camera system. In the GB group, there were marked a transilluminated letter or an ossicle on the inside tympanic membrane. In particular, a footplate of stapes was even transilluminated using the IR camera system in the GB group. This method can be useful in the diagnosis of diseases of the middle ear if it is clinically applied through further studies.

  15. Extratympanic observation of middle ear structure using a refractive index matching material (glycerol) and an infrared camera.

    PubMed

    Kong, Soo-Keun; Chon, Kyong-Myong; Goh, Eui-Kyung; Lee, Il-Woo; Wang, Soo-Geun

    2014-05-01

    High-resolution computed tomography has been used mainly in the diagnosis of middle ear disease, such as high-jugular bulb, congenital cholesteatoma, and ossicular disruption. However, certain diagnoses are confirmed through exploratory tympanotomy. There are few noninvasive methods available to observe the middle ear. The purpose of this study was to investigate the effect of glycerol as a refractive index matching material and an infrared (IR) camera system for extratympanic observation. 30% glycerol was used as a refractive index matching material in five fresh cadavers. Each material was divided into four subgroups; GN (glycerol no) group, GO (glycerol out) group, GI (glycerol in) group, and GB (glycerol both) group. A printed letter and middle ear structures on the inside tympanic membrane were observed using a visible and IR ray camera system. In the GB group, there were marked a transilluminated letter or an ossicle on the inside tympanic membrane. In particular, a footplate of stapes was even transilluminated using the IR camera system in the GB group. This method can be useful in the diagnosis of diseases of the middle ear if it is clinically applied through further studies.

  16. X-RAY AND NEAR-INFRARED OBSERVATIONS OF THE OBSCURED ACCRETING PULSAR IGR J18179-1621

    SciTech Connect

    Nowak, M. A.; Paizis, A.; Rodriguez, J.; Chaty, S.; Grinberg, V.; Wilms, J.; Chini, R. E-mail: ada@iasf-milano.inaf.it

    2012-10-01

    IGR J18179-1621 is an obscured accreting X-ray pulsar discovered by INTEGRAL on 2012 February 29. We report on our 20 ks Chandra-High Energy Transmission Gratings Spectrometer observation of the source performed on 2012 March 17, on two short contemporaneous Swift observations, and on our two near-infrared (K{sub s} , H{sub n} , and J{sub n} ) observations performed on 2012 March 13 and 26. We determine the most accurate X-ray position of IGR J18179-1621, {alpha}{sub J2000} = 18{sup h}17{sup m}52.{sup s}18, {delta}{sub J2000} = -16 Degree-Sign 21'31.''68 (90% uncertainty of 0.''6). A strong periodic variability at 11.82 s is clearly detected in the Chandra data, confirming the pulsating nature of the source, with the light-curve softening at the pulse peak. The quasi-simultaneous Chandra-Swift spectra of IGR J18179-1621 can be well fit by a heavily absorbed hard power law (N{sub H} = 2.2 {+-} 0.3 Multiplication-Sign 10{sup 23} cm{sup -2} and photon index {Gamma} = 0.4 {+-} 0.1) with an average absorbed 2-8 keV flux of 1.4 Multiplication-Sign 10{sup -11} erg cm{sup -2} s{sup -1}. At the Chandra-based position, a source is detected in our near-infrared (NIR) maps with K{sub s} 13.14 {+-} 0.04 mag, H{sub n} = 16 {+-} 0.1 mag, and no J{sub n} -band counterpart down to {approx}18 mag. The NIR source, compatible with 2MASS J18175218-1621316, shows no variability between 2012 March 13 and 26. Searches of the UKIDSS database show similar NIR flux levels at epochs six months prior to and after a 2007 February 11 archival Chandra observation where the source's X-ray flux was at least 87 times fainter. In many ways IGR J18179-1621 is unusual: its combination of a several week long outburst (without evidence of repeated outbursts in the historical record), high absorption column (a large fraction of which is likely local to the system), and 11.82 s period does not fit neatly into existing X-ray binary categories.

  17. Modeling infrared thermal emissions on Mars during dust storm of MY28: PFS/MEX observation

    NASA Astrophysics Data System (ADS)

    Haider, Syed A.; Kasaba, Yasumasa; Giuranna, Marco; Kuroda, Takeshi; Jethwa, Masoom P.

    2016-07-01

    We have analysed thermal emission spectra obtained from Planetary Fourier Spectrometer (PFS) onboard Mars Express (MEX) for Martian Year (MY) 28 in presence and absence of dust storm at low latitude. A radiative transfer model for dusty atmosphere of Mars is developed to estimate the thermal emission spectra at latitude range 0-10oS, 10-20oS and 20-30oS. These calculations are made at Ls=240o, 280o, 300o, and 320o between wave numbers 250-1400 cm-1. We have also retrieved brightness temperatures from thermal emission spectra by inverting the Planck function. The model reproduces the observed features at wave numbers 600-750 cm-1 and 900-1200 cm-1 due to absorptions by CO2 and dust respectively. In presence of dust storm thermal emission spectra and brightness temperature are reduced by a factor of ~ 2 between wave numbers 900-1200 cm-1. The altitude profiles of dust concentration are also estimated for different aerosol particles of sizes 0.2 to 3 micron. The best fit to the PFS measurements is obtained in presence of aerosol particle of size 0.2 micron.

  18. Galaxy evolution and large-scale structure in the far-infrared. I. IRAS pointed observations

    SciTech Connect

    Lonsdale, C.J.; Hacking, P.B.

    1989-04-01

    Redshifts for 66 galaxies were obtained from a sample of 93 60-micron sources detected serendipitously in 22 IRAS deep pointed observations, covering a total area of 18.4 sq deg. The flux density limit of this survey is 150 mJy, 4 times fainter than the IRAS Point Source Catalog (PSC). The luminosity function is similar in shape with those previously published for samples selected from the PSC, with a median redshift of 0.048 for the fainter sample, but shifted to higher space densities. There is evidence that some of the excess number counts in the deeper sample can be explained in terms of a large-scale density enhancement beyond the Pavo-Indus supercluster. In addition, the faintest counts in the new sample confirm the result of Hacking et al. (1989) that faint IRAS 60-micron source counts lie significantly in excess of an extrapolation of the PSC counts assuming no luminosity or density evolution. 81 refs.

  19. A FAR-INFRARED OBSERVATIONAL TEST OF THE DIRECTIONAL DEPENDENCE IN RADIATIVE GRAIN ALIGNMENT

    SciTech Connect

    Vaillancourt, John E.; Andersson, B.-G. E-mail: bg@sofia.usra.edu

    2015-10-10

    The alignment of interstellar dust grains with magnetic fields provides a key method for measuring the strength and morphology of the fields. In turn, this provides a means to study the role of magnetic fields from diffuse gas to dense star-forming regions. The physical mechanism for aligning the grains has been a long-term subject of study and debate. The theory of radiative torques, in which an anisotropic radiation field imparts sufficient torques to align the grains while simultaneously spinning them to high rotational velocities, has passed a number of observational tests. Here we use archival polarization data in dense regions of the Orion molecular cloud (OMC-1) at 100, 350, and 850 μm to test the prediction that the alignment efficiency is dependent upon the relative orientations of the magnetic field and radiation anisotropy. We find that the expected polarization signal, with a 180-degree period, exists at all wavelengths out to radii of 1.5 arcmin centered on the Becklin–Neugebauer Kleinmann-Low (BNKL) object in OMC-1. The probabilities that these signals would occur due to random noise are low (≲1%), and are lowest toward BNKL compared to the rest of the cloud. Additionally, the relative magnetic field to radiation anisotropy directions accord with theoretical predictions in that they agree to better than 15° at 100 μm and 4° at 350 μm.

  20. Observations of the near- to Mid-infrared Unidentified Emission Bands in the Interstellar Medium of the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Mori, Tamami I.; Sakon, Itsuki; Onaka, Takashi; Kaneda, Hidehiro; Umehata, Hideki; Ohsawa, Ryou

    2012-01-01

    We present the results of near- to mid-infrared slit spectroscopic observations (2.55-13.4 μm) of the diffuse emission toward nine positions in the Large Magellanic Cloud with the infrared camera on board AKARI. The target positions are selected to cover a wide range of the intensity of the incident radiation field. The unidentified infrared bands at 3.3, 6.2, 7.7, 8.6, and 11.3 μm are detected toward all the targets and ionized gas signatures; hydrogen recombination lines and ionic forbidden lines are detected toward three of them. We classify the targets into two groups: those without the ionized gas signatures (Group A) and those with the ionized signatures (Group B). Group A includes molecular clouds and photodissociation regions, whereas Group B consists of H II regions. In Group A, the band ratios of I 3.3 μm/I 11.3 μm, I 6.2 μm/I 11.3 μm, I 7.7 μm/I 11.3 μm, and I 8.6 μm/I 11.3 μm show positive correlation with the IRAS and AKARI colors, but those of Group B do not follow the correlation. We discuss the results in terms of the polycyclic aromatic hydrocarbon (PAH) model and attribute the difference to the destruction of small PAHs and an increase in the recombination due to the high electron density in Group B. In the present study, the 3.3 μm band provides crucial information on the size distribution and/or the excitation conditions of PAHs and plays a key role in the distinction of Group A from B. The results suggest the possibility of the diagram of I 3.3 μm/I 11.3 μm versus I 7.7 μm/I 11.3 μm as an efficient diagnostic tool to infer the physical conditions of the interstellar medium.

  1. SN 1987A after 18 Years: Mid-Infrared GEMINI and SPITZER Observations of the Remnant

    NASA Technical Reports Server (NTRS)

    Bouchet, Patrice; Dwek, Eli; Danziger, John; Arendt, Richard G.; DeBuizer, James M.; Park, Sangwook; Suntzeff, Nicholas B.; Kirshner, Robert P.; Challis, Peter

    2007-01-01

    We present high resolution 11.7 and 18.3 micron mid-IR images of SN 1987A obtained on day 6526 since the explosion with the Thermal-Region Camera and Spectrograph (T-ReCS) attached to the Gemini South 8m telescope. The 11.7 micron flux has increased significantly since our last observations on day 6067. The images clearly show that all the emission arises from the equatorial ring (ER). Nearly contemporaneous spectra obtained on day 6184 with the MIPS at 24 micron, on day 6130 with the IRAC in 3.6- 8 micron region, and on day 6190 with the IRS in the 12-37 micron instruments on board the Spitzer Space Telescope's show that the emission consists of thermal emission from silicate dust that condensed out in the red giant wind of the progenitor star. The dust temperature is 1662(sup +18) (sub -12) K, and the emitting dust mass is (2.6(sup +2.0 (sub -1.4)) x 10 (exp -6) M(solar). Lines of [Ne II] 12.82 micron and [Ne III] 15.56 pm are clearly present in the Spitzer spectrum, as well as a weak [Si II] 3 34.8 micron line. We also detect two lines near 26 micron which we tentatively ascribe to [Fe II] 25.99 pm and [0 IV] 25.91 micron. Comparison of the mid-IR Gemini 11.7 micron image with X-ray images obtained by Chandra, UV-optical images obtained by HST, and radio synchrotron images obtained by the ATCA show generally good correlation of the images across all wavelengths. Because of the limited resolution of the mid-IR images we cannot uniquely determine the location. or heating mechanism of the dust giving rise to the emission. The dust could be collisionally heated by the X-ray emitting plasma, providing a unique diagnostic of plasma conditions. Alternatively, the dust could be radiatively heated in the dense UV-optical knots that are overrun by the advancing supernova blast wave. In either case the dust-to-gas mass ratio in the circumstellar medium around the supernova is significantly lower than that in the general interstellar medium of the LMC, suggesting either a

  2. Mid-infrared imaging- and spectro-polarimetric subarcsecond observations of NGC 1068

    NASA Astrophysics Data System (ADS)

    Lopez-Rodriguez, E.; Packham, C.; Roche, P. F.; Alonso-Herrero, A.; Díaz-Santos, T.; Nikutta, R.; González-Martín, O.; Álvarez, C. A.; Esquej, P.; Espinosa, J. M. Rodríguez; Perlman, E.; Ramos Almeida, C.; Telesco, C. M.

    2016-06-01

    We present subarcsecond 7.5-13 μm imaging- and spectro-polarimetric observations of NGC 1068 using CanariCam on the 10.4-m Gran Telescopio CANARIAS. At all wavelengths, we find: (1) A 90 × 60 pc extended polarized feature in the northern ionization cone, with a uniform ˜44° polarization angle. Its polarization arises from dust and gas emission in the ionization cone, heated by the active nucleus and jet, and further extinguished by aligned dust grains in the host galaxy. The polarization spectrum of the jet-molecular cloud interaction at ˜24 pc from the core is highly polarized, and does not show a silicate feature, suggesting that the dust grains are different from those in the interstellar medium. (2) A southern polarized feature at ˜9.6 pc from the core. Its polarization arises from a dust emission component extinguished by a large concentration of dust in the galaxy disc. We cannot distinguish between dust emission from magnetically aligned dust grains directly heated by the jet close to the core, and aligned dust grains in the dusty obscuring material surrounding the central engine. Silicate-like grains reproduce the polarized dust emission in this feature, suggesting different dust compositions in both ionization cones. (3) An upper limit of polarization degree of 0.3 per cent in the core. Based on our polarization model, the expected polarization of the obscuring dusty material is ≲0.1 per cent in the 8-13 μm wavelength range. This low polarization may be arising from the passage of radiation through aligned dust grains in the shielded edges of the clumps.

  3. The Atmospheres of Titan and Saturn in the Infrared from Cassini: The Interplay Between Observation and Laboratory Studies

    NASA Astrophysics Data System (ADS)

    Jennings, D. E.; Nixon, C. A.; Flasar, M. F.; Kunde, V. G.; Coustenis, A.

    2011-05-01

    The Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft has been recording spectra of Saturn and Titan since its arrival in the Saturn system in 2004. CIRS, a Fourier transform spectrometer, observes the thermal infrared spectrum of both atmospheres from 10 to 1500 cm-1 with resolutions up to 0.5 cm-1 (Flasar et al. 2004). From these data CIRS provides global coverage of the molecular composition of the stratosphere and troposphere, as well as maps of temperature and winds. From such studies CIRS helps reveal the chemistry and evolutionary history of Saturn and Titan and their relationships to other Solar System bodies. The Cassini mission is continuing until 2017, permitting CIRS to search for atmospheric changes during more than a Saturnian season. By combining with results from Voyager (1980, 1981) the baseline becomes more than one Saturnian year (Coustenis et al. 2011). CIRS spectroscopy of the atmospheres of Saturn and Titan has raised a variety of questions that require new laboratory studies. A complete understanding of the CIRS high-resolution atmospheric spectra cannot be fully achieved without new or improved line positions and intensities for some trace molecules (e.g., Nixon et al. 2009). Isotopic variants of some of the more abundant species often need improved line parameters in order to derive isotopic ratios (e.g., Coustenis et al. 2008 and Fletcher et al. 2009). Isotopic ratios contain information about the history of an atmosphere if experimental fractionation rates are available (Jennings et al. 2009). Some aerosol and haze features continue to defy identification and will not be explained without better knowledge of how these materials are formed and until we obtain their laboratory spectra. The interaction between CIRS investigations and laboratory research has been productive and has already led to new discoveries.

  4. The Atmospheres of Titan and Saturn in the Infrared from Cassini: The Interplay Between Observation and Laboratory Studies

    NASA Technical Reports Server (NTRS)

    Jennings, D. E.; Nixon, C. A.; Flasar, F. M.; Kunde, V. G.; Coustenis, A.

    2011-01-01

    The Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft has been recording spectra of Saturn and Titan since its arrival in the Saturn system in 2004. CIRS, a Fourier transform spectrometer, observes the thermal infrared spectrum of both atmospheres from 10 to 1500/cm with resolutions up to 0.5/cm (Flasar et al. 2004). From these data CIRS provides global coverage of the molecular composition of the stratosphere and troposphere, as well as maps of temperature and winds. From such studies CIRS helps reveal the chemistry and evolutionary history of Saturn and Titan and their relationships to other Solar System bodies. The Cassini mission is continuing until 2017, permitting CIRS to search for atmospheric changes during more than a Saturnian season. By combining with results from Voyager (1980, 1981) the baseline becomes more than one Saturnian year (Coustenis et al. 2011). CIRS spectroscopy of the atmospheres of Saturn and Titan has raised a variety of questions that require new laboratory studies. A complete understanding of the CIRS high-resolution atmospheric spectra cannot be fully achieved without new or improved line positions and intensities for some trace molecules (e.g., Nixon et al. 2009). Isotopic variants of some of the more abundant species often need improved line parameters in order to derive isotopic ratios (e.g., Coustenis et al. 2008 and Fletcher et a!. 2009). Isotopic ratios contain information about the history of an atmosphere if experimental fractionation rates are available (Jennings et al. 2009). Some aerosol and haze features continue to defy identification and will not be explained without better knowledge of how these materials are formed and until we obtain their laboratory spectra. The interaction between CIRS investigations and laboratory research has been productive and has already led to new discoveries.

  5. Hubble Space Telescope Observations of the Luminous IRAS Source FSC 10214+4724: A Gravitationally Lensed Infrared Quasar

    NASA Technical Reports Server (NTRS)

    Eisenhardt, Peter R.; Armus, Lee; Hogg, David W.; Soifer, B. T.; Neugebauer, G.; Werner, Michael W.

    1996-01-01

    With a redshift of 2.3, the IRAS source FSC 10214+4724 is apparently one of the most luminous objects known in the universe. We present an image of FSC 10214+4724 at 0.8 pm obtained with the Hubble Space Telescope (HST) WFPC2 Planetary Camera. The source appears as an unresolved (less then 0.06) arc 0.7 long, with significant substructure along its length. The center of curvature of the arc is located near an elliptical galaxy 1.18 to the north. An unresolved component 100 times fainter than the arc is clearly detected on the opposite side of this galaxy. The most straightforward interpretation is that FSC 10214+4724 is gravitationally lensed by the foreground elliptical galaxy, with the faint component a counter-image of the IRAS source. The brightness of the arc in the HST image is then magnified by approx. 100, and the intrinsic source diameter is approx. 0.0l (80 pc) at 0.25 microns rest wavelength. The bolometric luminosity is probably amplified by a smaller factor (approx. 30) as a result of the larger extent expected for the source in the far-infrared. A detailed lensing model is presented that reproduces the observed morphology and relative flux of the arc and counterimage and correctly predicts the position angle of the lensing galaxy. The model also predicts reasonable values for the velocity dispersion, mass, and mass-to-light ratio of the lensing galaxy for a wide range of galaxy redshifts. A redshift for the lensing galaxy of -0.9 is consistent with the measured surface brightness profile from the image, as well as with the galaxy's spectral energy distribution. The background lensed source has an intrinsic luminosity approx. 2 x 10(exp 13) L(solar mass) and remains a highly luminous quasar with an extremely large ratio of infrared to optical/ultraviolet luminosity.

  6. Dehydration of uranyl nitrate hexahydrate to the trihydrate under ambient conditions as observed via dynamic infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Johnson, Timothy J.; Sweet, Lucas E.; Meier, David E.; Mausolf, Edward J.; Kim, Eunja; Weck, Philippe F.; Buck, Edgar C.; McNamara, Bruce K.

    2015-05-01

    Uranyl nitrate is a key species in the nuclear fuel cycle, but is known to exist in different states of hydration, including the hexahydrate [UO2(NO3)2(H2O)6] (UNH) and the trihydrate [UO2(NO3)2(H2O)3] (UNT) forms. Their stabilities depend on both relative humidity and temperature. Both phases have previously been studied by infrared transmission spectroscopy, but the data were limited by both instrumental resolution and the ability to prepare the samples as pellets without desiccating it. We report time-resolved infrared (IR) measurements using an integrating sphere that allow us to observe the transformation from the hexahydrate to the trihydrate simply by flowing dry nitrogen gas over the sample. Hexahydrate samples were prepared and confirmed via known XRD patterns, then measured in reflectance mode. The hexahydrate has a distinct uranyl asymmetric stretch band at 949.0 cm-1 that shifts to shorter wavelengths and broadens as the sample dehydrates and recrystallizes to the trihydrate, first as a blue edge shoulder but ultimately resulting in a doublet band with reflectance peaks at 966 and 957 cm-1. The data are consistent with transformation from UNH to UNT since UNT has two non-equivalent UO22+ sites. The dehydration of UO2(NO3)2(H2O)6 to UO2(NO3)2(H2O)3 is both a morphological and structural change that has the lustrous lime green crystals changing to the dull greenish yellow of the trihydrate. Crystal structures and phase transformation were confirmed theoretically using DFT calculations and experimentally via microscopy methods. Both methods showed a transformation with two distinct sites for the uranyl cation in the trihydrate, as opposed to a single crystallographic site in the hexahydrate.

  7. Quantification of blood flow velocity in stenosed arteries by the use of finite elements: an observer-independent noninvasive method.

    PubMed

    Mühlthaler, Hannes; Quatember, Bernhard; Fraedrich, Gustav; Mühlthaler, Markus; Pfeifer, Bernhard; Greiner, Andreas; Schocke, Michael F H

    2008-10-01

    Interventions for peripheral arterial disease should be designed to treat a physiological rather than an anatomic defect. Thus, for vascular surgeons, functional information about stenoses is as important as the anatomic one. In case of finding a stenosis by the use of magnetic resonance angiography, it would be a matter of particular interest to derive automatically and directly objective information about the hemodynamic influence on blood flow, caused by patient-specific stenoses. We developed a methodology to noninvasively perform numerical simulations of a patient's hemodynamic state on the basis of magnetic resonance images and by the means of the finite element method. We performed patient-specific three-dimensional simulation studies of the increase in systolic blood flow velocity due to stenoses using the commercial computational fluid dynamic software package FIDAP 8.52. The generation of a mesh defining the flow domain with a stenosis and some simulation results are shown.

  8. Observing the Transition from Equatorial to Axial CO Chemisorption: Infrared Photodissociation Spectroscopy of Yttrium Oxide-Carbonyls.

    PubMed

    Xie, Hua; Liu, Zhiling; Zhao, Zhi; Kong, Xiangtao; Fan, Hongjun; Tang, Zichao; Jiang, Ling

    2016-06-01

    A series of yttrium oxide-carbonyls are prepared via a laser vaporization supersonic cluster source in the gas phase and identified by mass-selected infrared photodissociation (IRPD) spectroscopy in the C-O stretching region and by comparing the observed IR spectra with those from quantum chemical calculations. For YO(CO)4(+), all four CO ligands prefer to occupy the equatorial site of the YO(+) unit, leading to a quadrangular pyramid with C4v symmetry. Two energetically nearly degenerate isomers are responsible for YO(CO)5(+), in which the fifth CO ligand is either inserted into the equatorial plane of YO(CO)4(+) or coordinated opposite the oxygen on the C4 axis. YO(CO)6(+) has a pentagonal bipyramidal structure with C5v symmetry, which includes five equatorial CO ligands and one axial CO ligand. The present IRPD spectroscopic and theoretical study of YO(CO)n(+) extends the first shell coordination number of CO ligands in metal monoxide carbonyls to six. The transition from equatorial to axial CO chemisorption in these yttrium oxide-carbonyls is fortunately observed at n = 5, providing new insight into ligand interactions and coordination for the transition metal oxides.

  9. Observing the Transition from Equatorial to Axial CO Chemisorption: Infrared Photodissociation Spectroscopy of Yttrium Oxide-Carbonyls.

    PubMed

    Xie, Hua; Liu, Zhiling; Zhao, Zhi; Kong, Xiangtao; Fan, Hongjun; Tang, Zichao; Jiang, Ling

    2016-06-01

    A series of yttrium oxide-carbonyls are prepared via a laser vaporization supersonic cluster source in the gas phase and identified by mass-selected infrared photodissociation (IRPD) spectroscopy in the C-O stretching region and by comparing the observed IR spectra with those from quantum chemical calculations. For YO(CO)4(+), all four CO ligands prefer to occupy the equatorial site of the YO(+) unit, leading to a quadrangular pyramid with C4v symmetry. Two energetically nearly degenerate isomers are responsible for YO(CO)5(+), in which the fifth CO ligand is either inserted into the equatorial plane of YO(CO)4(+) or coordinated opposite the oxygen on the C4 axis. YO(CO)6(+) has a pentagonal bipyramidal structure with C5v symmetry, which includes five equatorial CO ligands and one axial CO ligand. The present IRPD spectroscopic and theoretical study of YO(CO)n(+) extends the first shell coordination number of CO ligands in metal monoxide carbonyls to six. The transition from equatorial to axial CO chemisorption in these yttrium oxide-carbonyls is fortunately observed at n = 5, providing new insight into ligand interactions and coordination for the transition metal oxides. PMID:27158889

  10. Wide Field Near-infrared Photometry of 12 Galactic Globular Clusters: Observations Versus Models on the Red Giant Branch

    NASA Astrophysics Data System (ADS)

    Cohen, Roger E.; Hempel, Maren; Mauro, Francesco; Geisler, Douglas; Alonso-Garcia, Javier; Kinemuchi, Karen

    2015-12-01

    We present wide field near-infrared (near-IR) photometry of 12 Galactic globular clusters, typically extending from the tip of the cluster red giant branch (RGB) to the main sequence turnoff. Using recent homogenous values of cluster distance, reddening and metallicity, the resulting photometry is directly compared to the predictions of several recent libraries of stellar evolutionary models. Of the sets of models investigated, Dartmouth and Victoria-Regina models best reproduce the observed RGB morphology, albeit with offsets in J-{K}S color which vary in their significance in light of all sources of observational uncertainty. Therefore, we also present newly recalibrated relations between near-IR photometric indices describing the upper RGB versus cluster iron abundance as well as global metallicity. The influence of enhancements in alpha elements and helium are analyzed, and we find that the former affect the morphology of the upper RGB in accord with model predictions. Meanwhile, the empirical relations we derive are in good agreement with previous results, and minor discrepancies can likely be attributed to differences in the assumed cluster distances and reddenings. In addition, we present measurements of the horizontal branch (HB) and RGB bump magnitudes, finding a non-negligible dependence of the near-IR HB magnitude on cluster metallicity. Lastly, we discuss the influence of assumed cluster distances, reddenings and metallicities on our results, finding that our empirical relations are generally insensitive to these factors to within their uncertainties.

  11. INVESTIGATION OF MOLECULAR CLOUD STRUCTURE AROUND INFRARED BUBBLES: CARMA OBSERVATIONS OF N14, N22, AND N74

    SciTech Connect

    Sherman, Reid A.

    2012-11-20

    We present CARMA observations in 3.3 mm continuum and several molecular lines of the surroundings of N14, N22, and N74, three infrared bubbles from the GLIMPSE catalog. We have discovered 28 compact continuum sources and confirmed their associations with the bubbles using velocity information from HCO{sup +} and HCN. We have also mapped small-scale structures of N{sub 2}H{sup +} emission in the vicinity of the bubbles. By combining our data with survey data from GLIMPSE, MIPSGAL, BGPS, and MAGPIS, we establish about half of our continuum sources as star-forming cores. We also use survey data with the velocity information from our molecular line observations to describe the morphology of the bubbles and the nature of the fragmentation. We conclude from the properties of the continuum sources that N74 likely is at the near kinematic distance, which was previously unconfirmed. We also present tentative evidence of molecular clouds being more fragmented on bubble rims compared to dark clouds, suggesting that triggered star formation may occur, though our findings do not conform to a classic collect-and-collapse model.

  12. Our changing atmosphere: evidence based on long-term infrared solar observations at the Jungfraujoch since 1950.

    PubMed

    Zander, R; Mahieu, E; Demoulin, P; Duchatelet, P; Roland, G; Servais, C; De Mazière, M; Reimann, S; Rinsland, C P

    2008-03-01

    The Institute of Astrophysics of the University of Liège has been present at the High Altitude Research Station Jungfraujoch, Switzerland, since the late 1940s, to perform spectrometric solar observations under dry and weakly polluted high-mountain conditions. Several solar atlases of photometric quality, extending altogether from the near-ultra-violet to the middle-infrared, were produced between 1956 and 1994, first with grating spectrometers then with Fourier transform instruments. During the early 1970s, scientific concerns emerged about atmospheric composition changes likely to set in as a consequence of the growing usage of nitrogen-containing agricultural fertilisers and the industrial production of chlorine-bearing compounds such as the chlorofluorocarbons and hydro-chlorofluorocarbons. Resulting releases to the atmosphere with ensuing photolysis in the stratosphere and catalytic depletion of the protective ozone layer prompted a worldwide consortium of chemical manufacturing companies to solicit the Liège group to help in clarifying these concerns by undertaking specific observations with its existing Jungfraujoch instrumentation. The following pages evoke the main steps that led from quasi full sun-oriented studies to priority investigations of the Earth's atmosphere, in support of both the Montreal and the Kyoto Protocols.

  13. HERschel Observations of Edge-on Spirals (HEROES). I. Far-infrared morphology and dust mass determination

    NASA Astrophysics Data System (ADS)

    Verstappen, J.; Fritz, J.; Baes, M.; Smith, M. W. L.; Allaert, F.; Bianchi, S.; Blommaert, J. A. D. L.; De Geyter, G.; De Looze, I.; Gentile, G.; Gordon, K. D.; Holwerda, B. W.; Viaene, S.; Xilouris, E. M.

    2013-08-01

    Context. Edge-on spiral galaxies with prominent dust lanes provide us with an excellent opportunity to study the distribution and properties of the dust within them. The HEROES project was set up to observe a sample of seven large edge-on galaxies across various wavelengths for this investigation. Aims: Within this first paper, we present the Herschel observations and perform a qualitative and quantitative analysis on them, and we derive some global properties of the far infrared and submillimetre emission. Methods: We determine horizontal and vertical profiles from the Herschel observations of the galaxies in the sample and describe the morphology. Modified black-body fits to the global fluxes, measured using aperture photometry, result in dust temperatures and dust masses. The latter values are compared to those that are derived from radiative transfer models taken from the literature. Results: On the whole, our Herschel flux measurements agree well with archival values. We find that the exponential horizontal dust distribution model often used in the literature generally provides a good description of the observed horizontal profiles. Three out of the seven galaxies show signatures of extended vertical emission at 100 and 160 μm at the 5σ level, but in two of these it is probably due to deviations from an exactly edge-on orientation. Only for NGC 4013, a galaxy in which vertically extended dust has already been detected in optical images, we can detect vertically extended dust, and the derived scaleheight agrees with the value estimated through radiative transfer modelling. Our analysis hints at a correlation between the dust scaleheight and its degree of clumpiness, which we infer from the difference between the dust masses as calculated from modelling of optical data and from fitting the spectral energy distribution of Herschel datapoints. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia

  14. Millimeter and some near infra-red observations of short-period Miras and other AGB stars

    NASA Astrophysics Data System (ADS)

    Groenewegen, M. A. T.; Baas, F.; Blommaert, J. A. D. L.; Stehle, R.; Josselin, E.; Tilanus, R. P. J.

    1999-12-01

    Millimeter observations of 48 oxygen- and 20 carbon-rich AGB Miras with periods shorter than 400 days are presented. In addition, observations of 14 O-rich and 15 C-stars with longer, or no known, periods have also been obtained. The detection statistics is as follows: in 12CO J=1-0 and 2-1 we observed 97 stars, and detected 66 in at least one line. We find 24 new detections in the 1-0 line, 38 new detections in the 2-1 line, and 29 stars have been detected for the first time in one or both lines. In 12CO J=3-2 we observed 14 stars and detected 11, with 4 new detections. In 13CO J=2-1, 3-2 we observed 2 stars and had one new detection. In HCN(1-0) we observed 5 carbon stars and detected 3, one new. In SO(6_5-5_4) we observed the same 5 stars and detected none. In CS(3-2) we observed 8 carbon stars and detected 3, all new. In SiO(3-2, v=0) we observed 34 O-rich stars and detected 25, all new except one. Near-infrared JHK photometry is presented for seven stars. For four stars it is the first NIR data published. The luminosity and dust mass loss rate are obtained for seven very red stars with unknown pulsation period from modelling the spectral energy distribution (SED) and IRAS LRS spectra. Thereby, a new IR supergiant is confirmed (AFGL 2968). For the rest of the sample, luminosity and distance are obtained in a variety of ways: using hipparcos parallaxes, period-luminosity and period-M_K-relations combined with apparent K magnitudes, and kinematic distances. The dust mass loss rate is obtained from model fitting of the SED (either from the literature, or presented in the present paper), or from the observed IRAS 60 mu m flux, corrected for the photospheric contribution. The gas mass loss rate is derived from the observed CO line intensities, as presented here, combined with existing literature data, if any. This allows the derivation of the dust-to-gas ratio. Our and literature CO J = 3-2 data has been used to calibrate the relation between mass loss rate and peak

  15. Spitzer Infrared Spectrograph Observations of Magellanic Cloud Planetary Nebulae: The Nature of Dust in Low-Metallicity Circumstellar Ejecta

    NASA Astrophysics Data System (ADS)

    Stanghellini, Letizia; García-Lario, Pedro; García-Hernández, D. Anibal; Perea-Calderón, Jose V.; Davies, James E.; Manchado, Arturo; Villaver, Eva; Shaw, Richard A.

    2007-12-01

    We present 5-40 μm spectroscopy of 41 planetary nebulae (PNe) in the Magellanic Clouds, observed with the Infrared Spectrograph on board the Spitzer Space Telescope. The spectra show the presence of a combination of nebular emission lines and solid state features from dust, superimposed on the thermal IR continuum. By analyzing the 25 LMC and 16 SMC PNe in our sample we found that the IR spectra of 14 LMC and four SMC PNe are dominated by nebular emission lines, while the other spectra show solid state features. We observed that the solid state features are compatible with carbon-rich dust grains (SiC, polycyclic aromatic hydrocarbons [PAHs], etc.) in all cases but three PNe, which show oxygen-rich dust features. The frequency of carbonaceous dust features is generally higher in LMC than in SMC PNe. The spectral analysis allowed the correlations of the dust characteristics with the gas composition and morphology, and the properties of the central stars. We found that (1) all PNe with carbonaceous dust features have C/O>1, none of these being bipolar or otherwise highly asymmetric; (2) all PNe with oxygen-rich dust features have C/O<1, with probable high-mass progenitors if derived from single-star evolution (these PNe are either bipolar or highly asymmetric); (3) the dust temperature tracks the nebular and stellar evolution; and (4) the dust production efficiency depends on metallicity, with low-metallicity environments not favoring dust production. Based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.

  16. Herschel far-infrared observations of the Carina Nebula complex - The embedded young stellar and protostellar population

    NASA Astrophysics Data System (ADS)

    Gaczkowski, Benjamin; Preibisch, Thomas; Ratzka, Thorsten; Roccatagliata, Veronica; Ohlendorf, Henrike; Pekruhl, Stephanie

    2013-07-01

    At a distance of 2.3 kpc, the Carina Nebula is the nearest southern region with a large enough massive stellar population to sample the top of the IMF and displays all phenomena of massive star formation. We have performed a 9 square-degree Herschel far-infrared survey of the Carina Nebula complex (CNC) which revealed, for the first time, the very complex and filamentary small-scale structure of the dense clouds. We discovered 642 objects that are independently detected as point-like sources in at least two of the five Herschel bands. About 75% of these are Class 0 protostars with masses between about one and ten solar masses estimated from radiative transfer modeling. Taking the observational limits into account and extrapolating the observed number of Herschel-detected protostars over the stellar initial mass function suggests that the star formation rate of the CNC is about 0.017 solar masses per year. The spatial distribution of the Herschel young stellar objects (YSO) candidates is highly inhomogeneous and does not follow the distribution of cloud mass. Rather, most Herschel YSO candidates are found at the irradiated edges of clouds and pillars. The currently ongoing star formation process forms only low-mass and intermediate-mass stars, but no massive stars. The characteristic spatial configuration of the YSOs provides support to the picture that the formation of this latest stellar generation is triggered by the advancing ionization fronts. Around the bubble-shaped HII region Gum 31 (containing the young stellar cluster NGC 3324) in the north-western part of the CNC we identified 752 candidate YSOs from Spitzer, WISE, and Herschel data and analyzed their spectral energy distributions. Their location in the rim of the bubble is suggestive of their being triggered by a 'collect and collapse' scenario, which agrees well with the observed parameters of the region which we obtained from density and temperature maps from our Herschel data.

  17. Venus' night side atmospheric dynamics using near infrared observations from VEx/VIRTIS and TNG/NICS

    NASA Astrophysics Data System (ADS)

    Mota Machado, Pedro; Peralta, Javier; Luz, David; Gonçalves, Ruben; Widemann, Thomas; Oliveira, Joana

    2016-10-01

    We present night side Venus' winds based on coordinated observations carried out with Venus Express' VIRTIS instrument and the Near Infrared Camera (NICS) of the Telescopio Nazionale Galileo (TNG). With NICS camera, we acquired images of the continuum K filter at 2.28 μm, which allows to monitor motions at the Venus' lower cloud level, close to 48 km altitude. We will present final results of cloud tracked winds from ground-based TNG observations and from coordinated space-based VEx/VIRTIS observations.The Venus' lower cloud deck is centred at 48 km of altitude, where fundamental dynamical exchanges that help maintain superrotation are thought to occur. The lower Venusian atmosphere is a strong source of thermal radiation, with the gaseous CO2 component allowing radiation to escape in windows at 1.74 and 2.28 μm. At these wavelengths radiation originates below 35 km and unit opacity is reached at the lower cloud level, close to 48 km. Therefore, it is possible to observe the horizontal cloud structure, with thicker clouds seen silhouetted against the bright thermal background from the low atmosphere. By continuous monitoring of the horizontal cloud structure at 2.28 μm (NICS Kcont filter), it is possible to determine wind fields using the technique of cloud tracking. We acquired a series of short exposures of the Venus disk. Cloud displacements in the night side of Venus were computed taking advantage of a phase correlation semi-automated technique. The Venus apparent diameter at observational dates was greater than 32" allowing a high spatial precision. The 0.13" pixel scale of the NICS narrow field camera allowed to resolve ~3-pixel displacements. The absolute spatial resolution on the disk was ~100 km/px at disk center, and the (0.8–1") seeing-limited resolution was ~400 km/px. By co-adding the best images and cross-correlating regions of clouds the effective resolution was significantly better than the seeing-limited resolution. In order to correct for

  18. The design of passively athermalized narrow- and wide-field-of-view infrared objectives for the OBSERVER unmanned air vehicle

    NASA Astrophysics Data System (ADS)

    Simmons, Richard C.; Manning, Paul A.; Chamberlain, Trevor V.

    2004-12-01

    Some years ago QinetiQ introduced a short-range reconnaissance unmanned air vehicle (UAV), known as OBSERVER, which carried a visible three-camera sensor. To increase its versatility, a compatible infrared (IR) thermal imaging (TI) sensor was developed for the vehicle for operation in the 8-12mm waveband with a dual field of view function. The sensor incorporates a specially designed camera board, employing two IR lead scandium tantalate (PST) detectors based on UK un-cooled TI technology. Since no cooling engine is required for the detectors, the sensor module is very lightweight and hence well suited to its UAV application. So as to achieve the minimum possible payload for the vehicle, in addition to the lightweight detectors and electronics board, compact low mass optical solutions were devised for the camera objectives. These functioned at a relative aperture of f/1.0 and were designed to provide stable focus and imaging performance over a comparatively large temperature span (-10°C to + 50°C) to enable all weather operation. In order to achieve an athermalisation scheme devoid of elaborate electro-mechanical drives, thermally passive solutions were developed for the objectives in which the differing thermal characteristics of the components were designed to self-cancel optically. In this paper, the design and performance limitations of the optics are discussed and the procedure employed for establishing a thin lens pre-design for one of the objectives is described.

  19. Noninvasive observation of skeletal muscle contraction using near-infrared time-resolved reflectance and diffusing-wave spectroscopy.

    PubMed

    Belau, Markus; Ninck, Markus; Hering, Gernot; Spinelli, Lorenzo; Contini, Davide; Torricelli, Alessandro; Gisler, Thomas

    2010-01-01

    We introduce a method for noninvasively measuring muscle contraction in vivo, based on near-infrared diffusing-wave spectroscopy (DWS). The method exploits the information about time-dependent shear motions within the contracting muscle that are contained in the temporal autocorrelation function g(1)(τ,t) of the multiply scattered light field measured as a function of lag time, τ, and time after stimulus, t. The analysis of g(1)(τ,t) measured on the human M. biceps brachii during repetitive electrical stimulation, using optical properties measured with time-resolved reflectance spectroscopy, shows that the tissue dynamics giving rise to the speckle fluctuations can be described by a combination of diffusion and shearing. The evolution of the tissue Cauchy strain e(t) shows a strong correlation with the force, indicating that a significant part of the shear observed with DWS is due to muscle contraction. The evolution of the DWS decay time shows quantitative differences between the M. biceps brachii and the M. gastrocnemius, suggesting that DWS allows to discriminate contraction of fast- and slow-twitch muscle fibers. PMID:21054123

  20. Noninvasive observation of skeletal muscle contraction using near-infrared time-resolved reflectance and diffusing-wave spectroscopy

    NASA Astrophysics Data System (ADS)

    Belau, Markus; Ninck, Markus; Hering, Gernot; Spinelli, Lorenzo; Contini, Davide; Torricelli, Alessandro; Gisler, Thomas

    2010-09-01

    We introduce a method for noninvasively measuring muscle contraction in vivo, based on near-infrared diffusing-wave spectroscopy (DWS). The method exploits the information about time-dependent shear motions within the contracting muscle that are contained in the temporal autocorrelation function g(1)(τ,t) of the multiply scattered light field measured as a function of lag time, τ, and time after stimulus, t. The analysis of g(1)(τ,t) measured on the human M. biceps brachii during repetitive electrical stimulation, using optical properties measured with time-resolved reflectance spectroscopy, shows that the tissue dynamics giving rise to the speckle fluctuations can be described by a combination of diffusion and shearing. The evolution of the tissue Cauchy strain e(t) shows a strong correlation with the force, indicating that a significant part of the shear observed with DWS is due to muscle contraction. The evolution of the DWS decay time shows quantitative differences between the M. biceps brachii and the M. gastrocnemius, suggesting that DWS allows to discriminate contraction of fast- and slow-twitch muscle fibers.

  1. Submillimeter and far infrared line observations of M17 SW: A clumpy molecular cloud penetrated by UV radiation

    NASA Technical Reports Server (NTRS)

    Stutzki, J.; Stacey, G. J.; Genzel, R.; Harris, A. I.; Jaffe, d. T.; Lugten, J. B.

    1987-01-01

    Millimeter, submillimeter, and far infrared spectroscopic observations of the M17 SW star formation region are discussed. The results require the molecular cloud near the interface to be clumpy or filamentary. As a consequence, far ultraviolet radiation from the central OB stellar cluster can penetrate into the dense molecular cloud to a depth of several pc, thus creating bright and extended (CII) emission from the photodissociated surfaces of dense atomic and molecular clumps or sheets. The extended (CII) emission throughout the molecular cloud SW of the M17 complex has a level 20 times higher than expected from a single molecular cloud interface exposed to an ultraviolet radiation field typical of the solar neighborhood. This suggests that the molecular cloud as a whole is penetrated by ultraviolet radiation and has a clumpy or filamentary structure. The number of B stars expected to be embedded in the M17 molecular cloud probably can provide the UV radiation necessary for the extended (CII) emission. Alternatively, the UV radiation could be external, if the interstellar radiation in the vicinity of M17 is higher than in the solar neighborhood.

  2. Observations in the Saturn system during approach and orbital insertion, with Cassini's visual and infrared mapping spectrometer (VIMS)

    USGS Publications Warehouse

    Brown, R.H.; Baines, K.H.; Bellucci, G.; Buratti, B.J.; Capaccioni, F.; Cerroni, P.; Clark, R.N.; Coradini, A.; Cruikshank, D.P.; Drossart, P.; Formisano, V.; Jaumann, R.; Langevin, Y.; Matson, D.L.; McCord, T.B.; Mennella, V.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, C.; Baugh, N.; Griffith, C.A.; Hansen, G.B.; Hibbitts, C.A.; Momary, T.W.; Showalter, M.R.

    2006-01-01

    The Visual and Infrared Mapping Spectrometer observed Phoebe, Iapetus, Titan and Saturn's rings during Cassini's approach and orbital insertion. Phoebe's surface contains water ice, CO2, and ferrous iron. lapetus contains CO2 and organic materials. Titan's atmosphere shows methane fluorescence, and night-side atmospheric emission that may be CO2 and CH3D. As determined from cloud motions, the winds at altitude 25-30 km in the south polar region of Titan appear to be moving in a prograde direction at velocity ???1 m s-1. Circular albedo features on Titan's surface, seen at 2.02 ??m, may be palimpsests remaining from the rheological adjustment of ancient impact craters. As such, their long-term persistence is of special interest in view of the expected precipitation of liquids and solids from the atmosphere. Saturn's rings have changed little in their radial structure since the Voyager flybys in the early 1980s. Spectral absorption bands tentatively attributed to Fe2+ suggest that iron-bearing silicates are a source of contamination of the C ring and the Cassini Division. ?? ESO 2006.

  3. GROUND-BASED NEAR-INFRARED OBSERVATIONS OF THE SECONDARY ECLIPSE OF CoRoT-2b

    SciTech Connect

    Alonso, R.; Deeg, H. J.; Rabus, M.; Kabath, P.

    2010-04-15

    We present the results of a ground-based search for the secondary eclipse of the 3.3 M {sub Jup} transiting planet CoRoT-2b. We performed near-infrared photometry using the LIRIS instrument on the 4.2 m William Herschel Telescope, in the H and K{sub s} filters. We monitored the star around two expected secondary eclipses in two nights under very good observing conditions. For the depth of the secondary eclipse, in the H band we found a 3{sigma} upper limit of 0.17%, whereas we detected a tentative eclipse with a depth of 0.16% {+-} 0.09% in the K{sub s} band. These depths can be translated into brightness temperatures of T{sub H} < 2250 K and T{sub K{sub s}}= 1890{sup +260}{sub -350} K, which indicate an inefficient re-distribution of the incident stellar flux from the planet's day side to its night side. Our results are in agreement with the CoRoT optical measurement (Alonso et al.) and with Spitzer 4.5 and 8 {mu}m results (Gillon et al.)

  4. In-situ observations of adsorption and film formation on metal electrodes by synchrotron far infrared reflectance spectroscopy.

    SciTech Connect

    Bowmaker, G. A.; Hahn, F.; Leger, J. M.; Melendres, C. A.

    1999-05-17

    Adsorption and film formation are key processes associated with the passivation and inhibition of metallic corrosion. New experimental approaches are needed to advance our knowledge in these areas. We have developed the technique of Synchrotron Far Infrared Reflectance Spectroscopy (SFIRS) for in situ investigations of the structure and composition of surface films and adsorbed layers on metals. We demonstrate its application to the determination of the nature of surface films on copper in aqueous solutions and the adsorption of anions on gold. The anodic corrosion films on copper in alkaline solution were found to consist of Cu{sub 2}O in the passive region at about {minus}0.05 V vs SCE and CUO, together with CU(OH){sub 2}, at 0.30 V. We have also observed for the first time the adsorption of anions at monolayer coverage on the surface of a gold electrode in perchloric acid solution. Halides (Cl-, Br-), nitrate, sulfate, and phosphate have been studied. When two different anions are present in solution, the more strongly adsorbed species determines the corrosion behavior of the metal. This is illustrated in the competitive adsorption of bromide and phosphate on gold.

  5. Observations of Far-Infrared Molecular Emission Lines from the Orion Molecular Cloud. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Viscuso, P. J.

    1986-01-01

    The Orion Nebula was the subject of intensive study for over one hundred years. Recently, several far infrared transitions among the low-lying levels of OH were observed toward IRc2. The OH is thought to be abundant, and plays an important role in the chemical evolution of shock and post-shock regions. The OH emission serves as a sensitive probe of the temperature and density for the shock-processed gas. A rigorous treatment of the radiative transfer of these measured transitions was performed using the escape probability formalism. From this analysis, the temperature of the OH-emitting region was determined to be on the order of 40K. This suggests that the gas is part of the post-shock gas that has cooled sufficiently, most likely by way of radiative cooling by CO. Such cooling from shock temperatures of several degrees can be accomplished in 100 years. A molecular hydrogen density of 3 million/cubic cm and an OH column density of 1.0 x 10 to the 17th /sq cm is found. The beam filling factor is determined to be 36%.

  6. TESTING MASS LOSS IN LARGE MAGELLANIC CLOUD CEPHEIDS USING INFRARED AND OPTICAL OBSERVATIONS. II. PREDICTIONS AND TESTS OF THE OGLE-III FUNDAMENTAL-MODE CEPHEIDS

    SciTech Connect

    Neilson, Hilding R.; Ngeow, Chow-Choong; Kanbur, Shashi M.; Lester, John B.

    2010-06-20

    In this paper, we test the hypothesis that Cepheids have infrared excesses due to mass loss. We fit a model using the mass-loss rate and the stellar radius as free parameters to optical observations from the OGLE-III survey and infrared observations from the Two Micron All Sky Survey and SAGE data sets. The sample of Cepheids has predicted minimum mass-loss rates ranging from 0 to 10{sup -8} M{sub sun} yr{sup -1}, where the rates depend on the chosen dust properties. We use the predicted radii to compute the period-radius relation for LMC Cepheids and to estimate the uncertainty caused by the presence of infrared excess for determining angular diameters with the infrared surface brightness technique. Finally, we calculate the linear and nonlinear period-luminosity (P-L) relations for the LMC Cepheids at VIJHK + IRAC wavelengths and find that the P-L relations are consistent with being nonlinear at infrared wavelengths contrary to previous results.

  7. Robustness and infrared sensitivity of various observables in the application of AdS/CFT to heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Liu, Hong; Rajagopal, Krishna; Shi, Yeming

    2008-08-01

    We investigate the robustness with respect to the introduction of nonconformality of five properties of strongly coupled plasmas that have been calculated in Script N = 4 supersymmetric Yang-Mills (SYM) theory at nonzero temperature, motivated by the goal of understanding phenomena in relativistic heavy ion collisions. (The five properties are the jet quenching parameter, the velocity dependence of screening, and the drag and transverse and longitudinal momentum diffusion coefficients for a heavy quark pulled through the plasma.) We do so using a toy model in which nonconformality is introduced via a one-parameter deformation of the AdS black hole dual to the hot Script N = 4 SYM plasma. For values of this parameter which correspond to a degree of nonconformality comparable to that seen in lattice calculations of QCD thermodynamics at temperatures a few times that of the crossover to quark-gluon plasma, we find that the jet quenching parameter is affected by the nonconformality at the 30% level or less, the screening length is affected at the 20% level or less, but the drag and diffusion coefficients for a slowly moving heavy quark can be modified by as much as 80%. However, we show that all but one of the five properties that we investigate become completely insensitive to the nonconformality in the high velocity limit v→1. The exception is the jet quenching parameter, which is unique among the quantities that we investigate in being ``infrared sensitive'' even at v = 1, where it is defined. That is, it is the only high-velocity observable that we investigate which is sensitive to properties of the medium at infrared energy scales proportional to T, namely the scales where the quark-gluon plasma of QCD can be strongly coupled. The other four quantities all probe only scales that are larger than T by a factor that diverges as v→1, namely scales where the Script N = 4 SYM plasma can be strongly coupled but the quark-gluon plasma of QCD is not.

  8. Characterization of the 3D distribution of ozone and coarse aerosols in the Troposphere using IASI thermal infrared satellite observations

    NASA Astrophysics Data System (ADS)

    Cuesta, J.; Eremenko, M.; Dufour, G.; Hoepfner, M.; Orphal, J.

    2012-04-01

    Both tropospheric ozone and aerosols significantly affect air quality in megacities during pollution events. Moreover, living conditions may be seriously aggravated when such agglomerations are affected by wildfires (e.g. Russian fires over Moscow in 2010), which produce smoke and pollutant precursors, or even during dense desert dust outbreaks (e.g. recurrently over Beijing or Cairo). Moreover, since aerosols diffuse and absorb solar radiation, they have a direct impact on the photochemical production of tropospheric ozone. These interactions during extreme events of high aerosol loads are nowadays poorly known, even though they may significantly affect the tropospheric photochemical equilibrium. In order to address these issues, we have developed a new retrieval technique to jointly characterize the 3D distribution of both tropospheric ozone and coarse aerosols, using spaceborne observations of the infrared spectrometer IASI onboard MetOp-A satellite. Our methodology is based on the inversion of Earth radiance spectra in the atmospheric window from 8 to 12 μm measured by IASI and a «Tikhonov-Philipps»-type regularisation with constraints varying in altitude (as in [Eremenko et al., 2008, GRL; Dufour et al., 2010 ACP]) to simultaneously retrieve ozone profiles, aerosol optical depths at 10 μm and aerosol layer effective heights. Such joint retrieval prevents biases in the ozone profile retrieval during high aerosol load conditions. Aerosol retrievals using thermal infrared radiances mainly account for desert dust and the coarse fraction of biomass burning aerosols. We use radiances from 15 micro-windows within the 8-12 μm atmospheric window, which were carefully chosen (following [Worden et al., 2006 JGR]) for extracting the maximum information on aerosols and ozone and minimizing contamination by other species. We use the radiative transfer code KOPRA, including line-by-line calculations of gas absorption and single scattering for aerosols [Hoepfner et al

  9. Earth and Moon Observations by Thermal Infrared Imager TIR on Hayabusa2 and Applications to Asteroid 162173 Ryugu

    NASA Astrophysics Data System (ADS)

    Okada, Tatsuaki

    2016-04-01

    The Earth and the Moon were imaged by the thermal infrared imager TIR on Hayabusa2 during the Earth swing-by operation to change the trajectory of the spacecraft with a gravity assist of the Earth's mass. Hayabusa2 is the second sample-return from a near-Earth asteroid organized by Japan Aerospace Exploration Agency, and will visit and explore C-type small asteroid 162173 Ryugu, collect samples from the surface of the asteroid, and return them to the Earth [1-3]. TIR is a thermal infrared imager based on uncooled micro-bolometer array. It covers the temperature range from 150 to 460 K, and resolves the surface by 16° x 12° with 328 x 248 pixels with 0.05° per pixel [4, 5]. After the launch on 3 December 2014, TIR has been proven to work well by function tests, and its operation temperature has been adjusted by using the in-flight deep sky images. On 14 October 2015, TIR has detected the Earth and the Moon simultaneously from the distance of 2 x 107 km, and the alignment of -Z axis between TIR and the spacecraft attitude control system was checked. Afterwards, the Earth-Moon system were imaged many times and we could determine the alignment more precisely. Just after the Earth swing-by, TIR observed the Earth on 4 December 2015 and the Moon on the next day. We compared those thermal images with the calculated temperatures on the Earth and the Moon. It was a good opportunity to check the performance of thermal radiometry of this instrument, because there is no known calibration target before arrival at Ryugu. We found the temperature pattern on the Earth and the Moon are almost equal to the theoretical estimates [6]. The point spread feature shows that a point is imaged as a point, just the same as taken during the pre-flight tests. More detailed results will be presented. References: [1] Tsuda Y. et al. (2013) Acta. Astronautica, 91, 356-362. [2] Tachibana S. et al. (2014) Geochemical Journal, 48, 571-587. [3] Okada T. (2014) Proc. Intl. CJMT-1 workshop on

  10. Dehydration of Uranyl Nitrate Hexahydrate to Uranyl Nitrate Trihydrate under Ambient Conditions as Observed via Dynamic Infrared Reflectance Spectroscopy

    SciTech Connect

    Johnson, Timothy J.; Sweet, Lucas E.; Meier, David E.; Mausolf, Edward J.; Kim, Eunja; Weck, Philippe F.; Buck, Edgar C.; McNamara, Bruce K.

    2015-05-22

    the hexahydrate [UO2(NO3)2(H2O)6] (UNH) and the trihydrate [UO2(NO3)2(H2O)3] (UNT) forms. Their stabilities depend on both relative humidity and temperature. Both phases have previously been studied by infrared transmission spectroscopy, but the data were limited by both instrumental resolution and the ability to prepare the samples as pellets without desiccating them. We report time-resolved infrared (IR) measurements using an integrating sphere that allow us to observe the transformation from the hexahydrate to the trihydrate simply by flowing dry nitrogen gas over the sample. Hexahydrate samples were prepared and confirmed via known XRD patterns, then measured in reflectance mode. The hexahydrate has a distinct uranyl asymmetric stretch band at 949.0 cm-1 that shifts to shorter wavelengths and broadens as the sample dehydrates and recrystallizes to the trihydrate, first as a blue edge shoulder but ultimately resulting in a doublet band with reflectance peaks at 966 and 957 cm-1. The data are consistent with transformation from UNH to UNT since UNT has two non-equivalent UO22+ sites. The dehydration of UO2(NO3)2(H2O)6 to UO2(NO3)2(H2O)3 is both a morphological and structural change that has the lustrous lime green crystals changing to the dull greenish yellow of the trihydrate. Crystal structures and phase transformation were confirmed theoretically using DFT calculations and experimentally via microscopy methods. Both methods showed a transformation with two distinct sites for the uranyl cation in the trihydrate, as opposed to a single crystallographic site in the hexahydrate.

  11. Infrared and radio observations of W51: Another Orion-KL at a distance of 7kpc

    NASA Technical Reports Server (NTRS)

    Genzel, R.; Becklin, E. E.; Wynn-Williams, C. G.; Moran, J. M.; Reid, M. J.; Jaffe, D. T.; Downes, D.

    1981-01-01

    The bright infrared sources W51-IRS2 has at least three components with different physical and evolutionary properties. The spatial distribution and the near infrared spectra of the components in IRS2 are remarkably similar to, but more luminous than those found in Orion, where an H2 region of comparable linear size is also located close to a cluster of compact infrared sources. The characteristics of the nearby W51-NORTH H2O maser source, and the detection of 2 micro m H2 quadrupole emission in IRS2 indicate that the mass loss phenomena found in Orion-KL also exist in W51.

  12. Water and carbon dioxide distribution in the 67P/Churyumov-Gerasimenko coma from VIRTIS-M infrared observations

    NASA Astrophysics Data System (ADS)

    Migliorini, A.; Piccioni, G.; Capaccioni, F.; Filacchione, G.; Bockelée-Morvan, D.; Erard, S.; Leyrat, C.; Combi, M. R.; Fougere, N.; Crovisier, J.; Taylor, F. W.; De Sanctis, M. C.; Capria, M. T.; Grassi, D.; Rinaldi, G.; Tozzi, G. P.; Fink, U.

    2016-05-01

    Context. Studying the coma environment of comet 67P/Churyumov-Gerasimenko (67P) is one of the primary scientific goals of the VIRTIS experiment on the ESA Rosetta mission. Aims: The distribution and variability of water vapour and carbon dioxide in the comet's coma are needed to estimate their production rate, abundances in the nucleus, and the spatial distribution of the active regions. Methods: Infrared emission lines from vibrational bands of water and carbon dioxide at 2.67 and 4.27 μm, respectively, were observed by the VIRTIS-M imaging channel and mapped from close to the nucleus up to ~10 km altitude with a resolution of ~40 m/px. A dataset consisting of 74 observations in the 1-5 μm spectral range acquired from 8 to 14 April 2015 when 67P was at a heliocentric distance of 1.9 AU is analysed in this work. A statistical correlation between the gas distribution and the surface's active regions was performed. Results: The maximum H2O emission is observed within 3 km from the nucleus and is mainly concentrated above two active regions, Aten-Babi and Seth-Hapi, while the CO2 distribution appears more uniform with significant emissions coming from both the "head" and southern latitude regions. In the equatorial region, the column densities of both species decrease with altitude, although CO2 decreases more rapidly than H2O. The calculated CO2/H2O column density ratios above Aten-Babi and Seth-Hapi are 2.4 ± 0.6% and 3.0 ± 0.7%, respectively. A value equal to 3.9 ± 1.0% is observed at equatorial latitudes in the region encompassing Imothep. Conclusions: VIRTIS-M has mapped the distribution of water vapour and carbon dioxide around the nucleus of 67P with unprecedented spatial resolution. The different water and carbon dioxide outgassing above the surface, seen in the VIRTIS-M data, might be indicative of a different thermal history of the northern and southern hemispheres of 67P.

  13. Chandra Deep X-ray Observation of a Typical Galactic Plane Region and Near-Infrared Identification

    NASA Technical Reports Server (NTRS)

    Ebisawa, K.; Tsujimoto, M.; Paizis, A.; Hamaguichi, K.; Bamba, A.; Cutri, R.; Kaneda, H.; Maeda, Y.; Sato, G.; Senda, A.

    2004-01-01

    Using the Chandra Advanced CCD Imaging Spectrometer Imaging array (ACIS-I), we have carried out a deep hard X-ray observation of the Galactic plane region at (l,b) approx. (28.5 deg,0.0 deg), where no discrete X-ray source has been reported previously. We have detected 274 new point X-ray sources (4 sigma confidence) as well as strong Galactic diffuse emission within two partidly overlapping ACIS-I fields (approx. 250 sq arcmin in total). The point source sensitivity was approx. 3 x 10(exp -15)ergs/s/sq cm in the hard X-ray band (2-10 keV and approx. 2 x 10(exp -16) ergs/s/sq cm in the soft band (0.5-2 keV). Sum of all the detected point source fluxes account for only approx. 10 % of the total X-ray fluxes in the field of view. In order to explain the total X-ray fluxes by a superposition of fainter point sources, an extremely rapid increase of the source population is required below our sensitivity limit, which is hardly reconciled with any source distribution in the Galactic plane. Therefore, we conclude that X-ray emission from the Galactic plane has truly diffuse origin. Only 26 point sources were detected both in the soft and hard bands, indicating that there are two distinct classes of the X-ray sources distinguished by the spectral hardness ratio. Surface number density of the hard sources is only slightly higher than observed at the high Galactic latitude regions, strongly suggesting that majority of the hard X-ray sources are active galaxies seen through the Galactic plane. Following the Chandra observation, we have performed a near-infrared (NIR) survey with SOFI at ESO/NTT to identify these new X-ray sources. Since the Galactic plane is opaque in NIR, we did not see the background extragalactic sources in NIR. In fact, only 22 % of the hard sources had NIR counterparts which are most likely to be Galactic origin. Composite X-ray energy spectrum of those hard X-ray sources having NIR counterparts exhibits a narrow approx. 6.7 keV iron emission line, which

  14. Herschel far-infrared observations of the Carina Nebula complex. III. Detailed cloud structure and feedback effects

    NASA Astrophysics Data System (ADS)

    Roccatagliata, V.; Preibisch, T.; Ratzka, T.; Gaczkowski, B.

    2013-06-01

    Context. The star formation process in large clusters/associations can be strongly influenced by the feedback from high-mass stars. Whether the resulting net effect of the feedback is predominantly negative (cloud dispersal) or positive (triggering of star formation due to cloud compression) is still an open question. Aims: The Carina Nebula complex (CNC) represents one of the most massive star-forming regions in our Galaxy. We use our Herschel far-infrared observations to study the properties of the clouds over the entire area of the CNC (with a diameter of ≈3.2°, which corresponds to ≈125 pc at a distance of 2.3 kpc). The good angular resolution (10''-36'') of the Herschel maps corresponds to physical scales of 0.1-0.4 pc, and allows us to analyze the small-scale (i.e., clump-size) structures of the clouds. Methods: The full extent of the CNC was mapped with PACS and SPIRE in the 70, 160, 250, 350, and 500 μm bands. We determined temperatures and column densities at each point in these maps by modeling the observed far-infrared spectral energy distributions. We also derived a map showing the strength of the UV radiation field. We investigated the relation between the cloud properties and the spatial distribution of the high-mass stars and computed total cloud masses for different density thresholds. Results: Our Herschel maps resolve for the first time the small-scale structure of the dense clouds over the entire spatial extent of the CNC. Several particularly interesting regions, including the prominent pillars south of η Car, are analyzed in detail. We compare the cloud masses derived from the Herschel data with previous mass estimates based on sub-mm and molecular line data. Our maps also reveal a peculiar wave-like pattern in the northern part of the Carina Nebula. Finally, we characterize two prominent cloud complexes at the periphery of our Herschel maps, which are probably molecular clouds in the Galactic background. Conclusions: We find that the

  15. Dangling OH Vibrations of Water Molecules in Aqueous Solutions of Aprotic Polar Compounds Observed in the Near-Infrared Regime.

    PubMed

    Sagawa, Naoya; Shikata, Toshiyuki

    2015-06-25

    Near-infrared (NIR) absorption spectrum measurements over a frequency range from 4000 to 12000 cm(-1) were employed to investigate the effects of the presence of solute compounds to vibrational modes of water molecules in aqueous solutions of some aprotic hydroneutral polar compounds with large dipole moments, such as nitro compounds and nitriles. The obtained NIR spectra for the aqueous solutions were decomposed into three components: free water, solute, and water molecules affected by the presence of solutes. Newly determined NIR spectra of affected water molecules were well-described with at least four absorption modes observed at 7040, 6850, 6450, and 5640 cm(-1) for both the nitro compounds and nitriles. The highest frequency mode at 7040 cm(-1) possessing the strongest intensity was assigned to the first stretching overtone of affected water hydroxy (O-H) groups, which are nonhydrogen bonded to other water molecules and dangling. The second highest frequency mode at 6850 cm(-1) was assigned to the first stretching overtone of affected water O-H groups hydrated to other (free) water molecules. The third mode at 6400 cm(-1) was attributed to a combination mode of the fundamental stretching of O-H and the first overtone of the O-H bending mode of the affected water molecules. The lowest frequency mode at 5640 cm(-1) was assigned to the combination mode of the fundamental O-H stretching mode, the fundamental O-H bending mode, and the hindered rotational (libration) mode of the affected water molecules. Because absorption intensities of the third and lowest frequency modes for water molecules affected by the solutes depended on the sizes of alkyl groups of polar solutes, these two modes possibly result from the contribution of hydrophobic hydration effects.

  16. Optical and near-infrared observations of SN 2014ck: an outlier among the Type Iax supernovae

    NASA Astrophysics Data System (ADS)

    Tomasella, L.; Cappellaro, E.; Benetti, S.; Pastorello, A.; Hsiao, E. Y.; Sand, D. J.; Stritzinger, M.; Valenti, S.; McCully, C.; Arcavi, I.; Elias-Rosa, N.; Harmanen, J.; Harutyunyan, A.; Hosseinzadeh, G.; Howell, D. A.; Kankare, E.; Morales-Garoffolo, A.; Taddia, F.; Tartaglia, L.; Terreran, G.; Turatto, M.

    2016-06-01

    We present a comprehensive set of optical and near-infrared (NIR) photometric and spectroscopic observations for SN 2014ck, extending from pre-maximum to six months later. These data indicate that SN 2014ck is photometrically nearly identical to SN 2002cx, which is the prototype of the class of peculiar transients named SNe Iax. Similar to SN 2002cx, SN 2014ck reached a peak brightness MB = -17.37 ± 0.15 mag, with a post-maximum decline rate Δm15(B) = 1.76 ± 0.15 mag. However, the spectroscopic sequence shows similarities with SN 2008ha, which was three magnitudes fainter and faster declining. In particular, SN 2014ck exhibits extremely low ejecta velocities, ˜3000 km s-1 at maximum, which are close to the value measured for SN 2008ha and half the value inferred for SN 2002cx. The bolometric light curve of SN 2014ck is consistent with the production of 0.10^{+0.04}_{-0.03} M_{{⊙}} of 56Ni. The spectral identification of several iron-peak features, in particular Co II lines in the NIR, provides a clear link to SNe Ia. Also, the detection of narrow Si, S and C features in the pre-maximum spectra suggests a thermonuclear explosion mechanism. The late-phase spectra show a complex overlap of both permitted and forbidden Fe, Ca and Co lines. The appearance of strong [Ca II] λλ7292, 7324 again mirrors the late-time spectra of SN 2008ha and SN 2002cx. The photometric resemblance to SN 2002cx and the spectral similarities to SN 2008ha highlight the peculiarity of SN 2014ck, and the complexity and heterogeneity of the SNe Iax class.

  17. Seeing red in M32: Constraints on the stellar content from near- and mid-infrared observations and applications for studies of more distant galaxies {sup ,} {sup ,}

    SciTech Connect

    Davidge, T. J.

    2014-08-10

    The properties of asymptotic giant branch (AGB) stars in the Local Group galaxy M32 are investigated using ground- and space-based observations that span the 1-8 μm wavelength interval, with the goal of demonstrating the utility of infrared observations as probes of stellar content. Comparisons with isochrones indicate that the brightest resolved stars in M32 have ages of a few gigayears and are younger on average than AGB stars with the same intrinsic brightness in the outer disk of M31. Accounting for stellar variability is shown to be essential for modeling AGB luminosity functions (LFs). Model LFs that assume the star-forming history measured by Monachesi et al. and the variability properties of Galactic AGB stars match both the K and [5.8] LFs of M32. Models also suggest that the slope of the [5.8] LF between M{sub [5.8]} = –8.5 and –10.0 is sensitive to the mix of stellar ages, and a sizeable fraction of the stars in M32 must have an age older than 7 Gyr in order to match the [5.8] LF. The structural properties of M32 in the infrared are also investigated. The effective radii that are computed from near-infrared and mid-infrared isophotes are similar to those measured at visible wavelengths, suggesting that the stellar content of M32 is well mixed. However, isophotes at radii >16'' (>60 pc) in the near- and mid-infrared are flatter than those at visible wavelengths. The coefficient of the fourth-order cosine term in the Fourier expansion of isophotes changes from 'boxy' values at r < 16'' to 'disky' values at r > 48''in [3.6] and [4.5]. The mid-infrared colors near the center of M32 do not vary systematically with radius, providing evidence of a well mixed stellar content in this part of the galaxy.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  19. MID-INFRARED SPECTROPHOTOMETRIC OBSERVATIONS OF FRAGMENTS B AND C OF COMET 73P/SCHWASSMANN-WACHMANN 3

    SciTech Connect

    Harker, David E.; Woodward, Charles E.; Kelley, Michael S.; Sitko, Michael L.; Wooden, Diane H.; Lynch, David K.; Russell, Ray W. E-mail: chelsea@astro.umn.edu

    2011-01-15

    We present mid-infrared spectra and images from the Gemini-N (+ Michelle) observations of fragments SW3-[B] and SW3-[C] of the ecliptic (Jupiter family) comet 73P/Schwassmann-Wachmann 3 pre-perihelion. We observed fragment B soon after an outburst event (between 2006 April 16-26 UT) and detected crystalline silicates. The mineralogy of both fragments was dominated by amorphous carbon and amorphous pyroxene. The grain size distribution (assuming a Hanner-modified power law) for fragment SW3-[B] has a peak grain radius of a{sub p} {approx} 0.5 {mu}m, and for fragment SW3-[C], a{sub p} {approx} 0.3 {mu}m; both values are larger than the peak grain radius of the size distribution for the dust ejected from ecliptic comet 9P/Tempel 1 during the Deep Impact event (a{sub p} = 0.2 {mu}m). The silicate-to-carbon ratio and the silicate crystalline mass fraction for the submicron to micron-sized portion of the grain size distribution on the nucleus of fragment SW3-[B] were 1.341{sup +0.250}{sub -0.253} and 0.335{sup +0.089}{sub -0.112}, respectively, while on the nucleus of fragment SW3-[C] they were 0.671{sup +0.076}{sub -0.076} and 0.257{sup +0.039}{sub -0.043}, respectively. The similarity in mineralogy and grain properties between the two fragments implies that 73P/Schwassmann-Wachmann 3 is homogeneous in composition. The slight differences in grain size distribution and silicate-to-carbon ratio between the two fragments likely arise because SW3-[B] was actively fragmenting throughout its passage while the activity in SW3-[C] was primarily driven by jets. The lack of diverse mineralogy in the fragments SW3-[B] and SW3-[C] of 73P/Schwassmann-Wachmann 3 along with the relatively larger peak in the coma grain size distribution suggests that the parent body of this comet may have formed in a region of the solar nebula with different environmental properties than the natal sites where comet C/1995 O1 (Hale-Bopp) and 9P/Tempel 1 nuclei aggregated.

  20. RY Scuti: Infrared and radio observations of the mass-loss wind of a massive binary star system

    NASA Technical Reports Server (NTRS)

    Gehrz, R. D.; Hayward, T. L.; Houck, J. R.; Miles, J. W.; Hjellming, R. M.; Jones, T. J.; Woodward, Charles E.; Prentice, Ricarda; Forrest, W. J.; Libonate, S.

    1995-01-01

    We report infrared (IR) imaging, IR photometry, IR spectroscopy, optical/IR photopolarimetry, and Very Large Array (VLA) radio observations of the peculiar binary star RY Scuti. These observations provide an unprecedented view of the detailed spatial structure of the equatorial mass-loss wind of a massive, luminous, 'overcontact' binary system. The binary star (0.43 AU separation) is surrounded by a flattened equatorial disk with an outer radius of approximately = 3 x 10(exp 16) cm (2000 AU) that emits strongly in the IR and radio. The inside of the disk is ionized and emits free-free radiation from hydrogen and 12.8 micrometers forbidden-line emission from (Ne II); the outside of the disk emits thermal radiation from silicate dust. Radio continuum emission is also produced in a compact H II region surrounding the binary. The dust may have a polycyclic aromatic hydrocarbon (PAH) component. We use a rudimentary geometric model in which the thermal IR and radio emission from the disk are assumed to arise in a pair of concentric toroidal rings to estimate the physical properties of the disk. The mean radius of the ionized gas toroid is approximately = 1.3 x 10(exp 16) cm (870 AU), and the mean radius of the dust toroid is approximately = 2.2 x 10(exp 16) cm (1470 AU). RY Scuti has a small intrinsic polarization, with the electric vector perpendicular to the equatorial disk, that is probably caused by electron scattering from hot gas close to the central binary. We conclude that neon in the nebula is overabundant with respect to hydrogen and helium by a factor of between 1.6 and 10. Our IR/radio image data suggest that the circumstellar disk is part of an extensive radiation driven mass-loss outflow that is strongly confined to the equatorial plane of the binary system. The sharp spatial separation of the outer dust torous from the inner ionized gas torus confirms earlier suggestions that dust formation in the circumstellar ejecta of very hot stars must occur in

  1. The Early Infrared Temporal Development of Nova Delphini 2013 (V339 DEL) Observed with the Stratospheric Observatory for Infrared Astronomy (SOFIA) and from the Ground

    NASA Astrophysics Data System (ADS)

    Gehrz, R. D.; Evans, A.; Helton, L. A.; Shenoy, D. P.; Banerjee, D. P. K.; Woodward, C. E.; Vacca, W. D.; Dykhoff, D. A.; Ashok, N. M.; Cass, A. C.; Carlon, R. L.; Corgan, D. T.; Eyres, S. P. S.; Joshi, V.; Keller, Luke D.; Krautter, J.; Liimets, T.; Rushton, M.; Starrfield, S.

    2015-10-01

    We present ground-based infrared photometry, JHK spectroscopy, and 5-28 μm SOFIA FORCAST spectroscopy documenting the early temporal development of Nova Delphini 2013 (V339 Del). We derive a distance of ˜4.5 kpc using data available from the early expansion of the fireball. This distance gives an outburst luminosity of ˜8.3 × 105 {L}⊙ making V339 Del the most luminous CO nova on record. Our data provide new constraints on the ejected gas mass and the dust yield in fast CO novae. The ejected gas mass as estimated by the cutoff wavelength during the free-free emission phase is ˜7.5 × 10-5 {M}⊙ . There is evidence for the formation of ˜1.2(±0.4) × 10-7 {M}⊙ of dust about 102 days after outburst. The gas to dust ratio of ˜470/1-940/1 implies that dust production was much less efficient in V339 Del than is the case for most CO novae.

  2. Herschel/PACS observations of young sources in Taurus: the far-infrared counterpart of optical jets

    NASA Astrophysics Data System (ADS)

    Podio, L.; Kamp, I.; Flower, D.; Howard, C.; Sandell, G.; Mora, A.; Aresu, G.; Brittain, S.; Dent, W. R. F.; Pinte, C.; White, G. J.

    2012-09-01

    Context. Observations of the atomic and molecular line emission associated with jets and outflows emitted by young stellar objects provide sensitive diagnostics of the excitation conditions, and can be used to trace the various evolutionary stages they pass through as they evolve to become main sequence stars. Aims: To understand the relevance of atomic and molecular cooling in shocks, and how accretion and ejection efficiency evolves with the evolutionary state of the sources, we will study the far-infrared counterparts of bright optical jets associated with Class I and II sources in Taurus (T Tau, DG Tau A, DG Tau B, FS Tau A+B, and RW Aur). Methods: We have analysed Herschel/PACS observations of a number of atomic ([O i]63 μm, 145 μm, [C ii]158 μm) and molecular (high-J CO, H2O, OH) lines, collected within the open time key project GASPS (PI: W. R. F. Dent). To constrain the origin of the detected lines we have compared the obtained FIR emission maps with the emission from optical-jets and millimetre-outflows, and the measured line fluxes and ratios with predictions from shock and disk models. Results: All of the targets are associated with extended emission in the atomic lines; in particular, the strong [O i] 63 μm emission is correlated with the direction of the optical jet/mm-outflow. The line ratios suggest that the atomic lines can be excited in fast dissociative J-shocks occurring along the jet. The molecular emission, on the contrary, originates from a compact region, that is spatially and spectrally unresolved, and lines from highly excited levels are detected (e.g., the o-H2O 818-707 line, and the CO J = 36-35 line). Disk models are unable to explain the brightness of the observed lines (CO and H2O line fluxes up to 10-15-6 × 10-16 W m-2). Slow C- or J-shocks with high pre-shock densities reproduce the observed H2O and high-J CO lines; however, the disk and/or UV-heated outflow cavities may contribute to the observed emission. Conclusions

  3. Use of finite-difference arrays of observation wells to estimate evapotranspiration from ground water in the Arkansas River Valley, Colorado

    USGS Publications Warehouse

    Weeks, Edwin P.; Sorey, M.L.

    1973-01-01

    A method to determine evapotranspiration from ground water was tested at four sites in the flood plain of the Arkansas River in Colorado. Approximate ground-water budgets were obtained by analyzing water-level data from observation wells installed in five-point arrays. The analyses were based on finite difference approximations of the differential equation describing ground-water flow. Data from the sites were divided into two groups by season. It was assumed that water levels during the dormant season were unaffected by evapotranspiration of ground water or by recharge, collectively termed 'accretion.' Regression analyses of these data were made to provide an equation for separating the effects of changes in aquifer storage and of aquifer heterogeneity from those due to accretion during the growing season. The data collected during the growing season were thus analyzed to determine accretion.

  4. Fermionic quantum criticality in honeycomb and π -flux Hubbard models: Finite-size scaling of renormalization-group-invariant observables from quantum Monte Carlo

    NASA Astrophysics Data System (ADS)

    Parisen Toldin, Francesco; Hohenadler, Martin; Assaad, Fakher F.; Herbut, Igor F.

    2015-04-01

    We numerically investigate the critical behavior of the Hubbard model on the honeycomb and the π -flux lattice, which exhibits a direct transition from a Dirac semimetal to an antiferromagnetically ordered Mott insulator. We use projective auxiliary-field quantum Monte Carlo simulations and a careful finite-size scaling analysis that exploits approximately improved renormalization-group-invariant observables. This approach, which is successfully verified for the three-dimensional XY transition of the Kane-Mele-Hubbard model, allows us to extract estimates for the critical couplings and the critical exponents. The results confirm that the critical behavior for the semimetal to Mott insulator transition in the Hubbard model belongs to the Gross-Neveu-Heisenberg universality class on both lattices.

  5. Large Scale Variability of Mid-Tropospheric Carbon Dioxide as Observed by the Atmospheric Infrared Sounder (AIRS) on the NASA EOS Aqua Platform

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Olsen, Edward T.

    2012-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral infrared instrument on the EOS Aqua Spacecraft, launched on May 4, 2002. AIRS has 2378 infrared channels ranging from 3.7 microns to 15.4 microns and a 13.5 km footprint. AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), produces temperature profiles with 1K/km accuracy, water vapor profiles (20%/2km), infrared cloud height and fraction, and trace gas amounts for CO2, CO, SO2, O3 and CH4 in the mid to upper troposphere. AIRS wide swath(cedilla) +/-49.5 deg , enables daily global daily coverage for over 95% of the Earth's surface. AIRS data are used for weather forecasting, validating climate model distribution and processes, and observing long-range transport of greenhouse gases. In this study, we examine the large scale and regional horizontal variability in the AIRS Mid-tropospheric Carbon Dioxide product as a function of season and associate the observed variability with known atmospheric transport processes, and sources and sinks of CO2.

  6. Time-resolved infrared-spectroscopic observation of relaxation and reaction processes during and after infrared-multiphoton excitation of 12CF3I and 13CF3I with shaped nanosecond pulses

    NASA Astrophysics Data System (ADS)

    Quack, Martin; Schwarz, René; Seyfang, Georg

    1992-06-01

    We have produced shaped infrared laser pulses of several kinds ranging from about 2-100 ns duration using a line tuned CO2 laser combined with intracavity absorbers and a CdTe electro-optical switch. The time-dependent infrared absorption of 12CF3I and 13CF3I during and after infrared-multiphoton excitation with these pulses was followed by means of a line tuned continuous wave-CO2 laser and a fast HgCdTe infrared detector (time resolution about 1 ns). The effective time-dependent absorption cross section shows fluence-dependent decay at large fluence with an effective exponential decay constant kI,σ≂1.12 cm2 J-1. This can be interpreted by first generation and then decay by further radiative pumping of highly excited levels of CF3I. The results have been analyzed by master equation modeling using a nonlinear case B/C master equation for multiphoton excitation and very simple models for the absorption properties of highly excited molecules. After nanosecond excitation to very high levels, one finds unimolecular decay CF3I→CF3+I with distinct rate constants (2±1)×108 and (5±4)×106 s-1, which corresponds to ensembles of molecules differing by one CO2 -laser quantum of energy, in agreement with unimolecular rate theory and master equation models. The most striking observation is a slow, collision-free intramolecular rovibrational redistribution process observed by real time spectroscopy on the nanosecond time scale for molecules excited by modest fluence corresponding to typical average energies of five CO2 laser quanta and somewhat more.

  7. Photolysis of Hi-CO Nitrogenase – Observation of a Plethora of Distinct CO Species using Infrared Spectroscopy

    PubMed Central

    Yan, Lifen; Dapper, Christie H.; George, Simon J.; Wang, Hongxin; Mitra, Devrani; Dong, Weibing; Newton, William E.; Cramer, Stephen P.

    2015-01-01

    Fourier transform infrared spectroscopy (FT-IR) was used to study the photochemistry of CO-inhibited Azotobacter vinelandii nitrogenase using visible light at cryogenic temperatures. The FT-IR difference spectrum of photolyzed hi-CO at 4 K comprises negative bands at 1973 cm−1 and 1679 cm−1 together with positive bands at 1711 cm−1, 2135 and 2123 cm−1. The negative bands are assigned to a hi-CO state that comprises 2 metal-bound CO ligands, one terminally bound, and one bridged and/or protonated species. The positive band at 1711 cm−1 is assigned to a lo-CO product with a single bridged and/or protonated metal-CO group. We term these species ‘Hi-1’ and ‘Lo-1’ respectively. The high-energy bands are assigned to a liberated CO trapped in the protein pocket. Warming results in CO recombination, and the temperature dependence of the recombination rate yields an activation energy of 4 kJ mol−1. Two α-H195 variant enzymes yielded additional signals. Asparagine substitution, α-H195N, gives a spectrum containing 2 negative ‘Hi-2’ bands at 1936 and 1858 cm−1 with a positive ‘Lo-2’ band at 1780 cm−1, while glutamine substitution, α-H195Q, produces a complex spectrum that includes a third CO species, with negative ‘Hi-3’ bands at 1938 and 1911 cm−1 and a positive feature ‘Lo-3’ band at 1921 cm−1. These species can be assigned to a combination of terminal, bridged, and possibly protonated CO groups bound to the FeMo-cofactor active site. The proposed structures are discussed in terms of both CO inhibition and the mechanism nitrogenase catalysis. Given the intractability of observing nitrogenase intermediates by crystallographic methods, IR-monitored photolysis appears to be a promising and information-rich probe of nitrogenase structure and chemistry. PMID:27630531

  8. AN INFRARED-LUMINOUS MERGER WITH TWO BIPOLAR MOLECULAR OUTFLOWS: ALMA AND SMA OBSERVATIONS OF NGC 3256

    SciTech Connect

    Sakamoto, Kazushi; Aalto, Susanne; Combes, Francoise; Evans, Aaron; Peck, Alison

    2014-12-20

    We report Atacama Large Millimeter/sub-millimeter Array and Submillimeter Array observations of the infrared-luminous merger NGC 3256, the most luminous galaxy within z = 0.01. Both of the two merger nuclei separated by 5'' (0.8 kpc) have a molecular gas concentration, a nuclear disk, with Σ{sub mol} > 10{sup 3} M {sub ☉} pc{sup –2}. The northern nucleus is more massive and is surrounded by molecular spiral arms. Its nuclear disk is face-on, while the southern nuclear disk is almost edge-on. The high-velocity molecular gas in the system can be resolved into two molecular outflows from the two nuclei. The one from the northern nucleus is part of a starburst-driven superwind seen nearly pole-on. Its maximum velocity is >750 km s{sup –1} and its mass outflow rate is >60 M {sub ☉} yr{sup –1} for a conversion factor X{sub CO}=N{sub H{sub 2}}/I{sub CO(1−0)} of 1 × 10{sup 20} cm{sup –2} (K km s{sup –1}){sup –1}. The molecular outflow from the southern nucleus is a highly collimated bipolar jet seen nearly edge-on. Its line-of-sight velocity increases with distance, out to 300 pc from the nucleus, to the maximum de-projected velocity of ∼2000 km s{sup –1} for the estimated inclination and ≳1000 km s{sup –1} taking into account the uncertainty. Its mass outflow rate is estimated to be >50 M {sub ☉} yr{sup –1} for the same X {sub CO}. This southern outflow has indications of being driven by a bipolar radio jet from an active galactic nucleus that recently weakened. The sum of these outflow rates, although subject to the uncertainty in the molecular mass estimate, either exceeds or compares to the total star formation rate. The feedback from nuclear activity through molecular outflows is therefore significant in the gas consumption, and hence evolution, of this system.

  9. Spitzer/infrared spectrograph investigation of mipsgal 24 μm compact bubbles: low-resolution observations

    SciTech Connect

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

    2014-12-01

    We present Spitzer/InfraRed Spectrograph (IRS) low-resolution observations of 11 compact circumstellar bubbles from the MIPSGAL 24 μm Galactic plane survey. We find that this set of MIPSGAL bubbles (MBs) is divided into two categories and that this distinction correlates with the morphologies of the MBs in the mid-infrared (IR). The four MBs with central sources in the mid-IR exhibit dust-rich, low-excitation spectra, and their 24 μm emission is accounted for by the dust continuum. The seven MBs without central sources in the mid-IR hav