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  • 11
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    Infrared reflection nebulae in Orion Molecular Cloud 2 (1986)
    Institute of Physics
    Details
    Publication Date: 1986-12-01
    Print ISSN: 0004-637X
    Electronic ISSN: 1538-4357
    Topics: Physics
    Published by Institute of Physics
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    PAPER CURRENT
  • 12
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    SIRTF: The Space Infrared Telescope Facility (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A quick overview of the work which was performed to bring the Space Infrared Telescope Facility to its present state of readiness is presented.
    Keywords: ASTRONOMY
    Type: Proceedings of the Second Infrared Detector Technology Workshop; 8 p
    Format: text
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    NASA TECHNICAL REPORTS
  • 13
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    Simultaneous submillimeter and infrared observations of flat-spectrum radio sources (1986)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Observations are presented of 12 extragalactic nonthermal radio emission sources made at eight wavelengths between 1.25 and 1000 microns, including the important submillimeter wavelength of 350 microns. Nine of the objects were detected at 350 microns, roughly double the number of objects of this type that have previously been detected at this wavelength. The majority of the observations were made within a three-week time span. The results, combined with other studies, show that these objects generally have flat energy distributions at wavelengths longer than 1 mm that break in most cases between 350 microns and 1 mm. At wavelengths shorter than 1 mm, the energy distributions fall with a rough power-law behavior with a spectral index of about -1. For many of the objects, there is a definite break or curvature in the energy distributions at wavelengths near 2.2 microns, with the fluxes falling even more steeply into the near infrared. At the time of the observations, both OJ 287 and 3C 273 were undergoing flares. The results are generally consistent with the flares propagating out to longer wavelengths with time.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 304; 646-650
    Format: text
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    NASA TECHNICAL REPORTS
  • 14
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    Far-infrared and submillimeter photometry of evolved stars (1985)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Broad-band photometric observations at far infrared and submillimeter wavelengths (lambda is greater than 30 microns and less than 1) provide a unique probe of circumstellar shells in evolved objects and of the mass loss processes which produce them. The problems which these observations explore include: dust properties and dust-to-gas ratios in the outflowing material, the mass and structure of the circumstellar shell, and the pumping mechanism for maser emission. This contribution reviews the early work in this still largely unexploited field and reports results in each of the areas listed above. The dramatic advances forthcoming in this area from the IRAS satellite are previewed along with further progress which will come from the next generation of infrared and submillimeter telescopes.
    Keywords: ASTROPHYSICS
    Format: text
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    NASA TECHNICAL REPORTS
  • 15
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    Infrared astronomy after IRAS (1986)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The development of infrared astronomy in the wake of IRAS is discussed. Attention is given to an overview of next generation infrared telescope technology, with emphasis on the Space Infrared Telescope Facility (SIRTF) which has been built to replace IRAS in the 1990s. Among the instruments to be included on SIRTF are: a wide-field high-resolution camera covering the infrared range 3-30 microns with large arrays of detectors; an imaging photometer operating in the range 3-700 microns; and a spectrograph covering the range 2.5-200 microns with resolutions of 2 and 0.1 percent. Observational missions for the SIRTF are proposed in connection with: planetary formation; star formation; cosmic energy sources; active galactic nuclei; and quasars.
    Keywords: ASTRONOMY
    Type: Science (ISSN 0036-8075); 231; 807-814
    Format: text
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    NASA TECHNICAL REPORTS
  • 16
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    IRAS surface brightness maps of reflection nebulae in the Pleiades (1987)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Surface brightness maps at 12, 25, 60, and 100 microns were made of a 2.5 deg x 2.5 deg area of the reflection nebulae in the Pleiades by coadding IRAS scans of this region. Emission is seen surrounding 17 Tau, 20 Tau, 23 Tau, and 25 Tau in all four bands, coextensive with the visible reflection nebulosity, and extending as far as 30 arcminutes from the illuminating stars. The infrared energy distributions of the nebulae peak in the 100 micron band, but up to 40 percent of the total infrared power lies in the 12 and 25 micron bands. The brightness of the 12 and 25 micron emission and the absence of temperature gradients at these wavelengths are inconsistent with the predictions of equilibrium thermal emission models. The emission at these wavelengths appears to be the result of micron nonequilibrium emission from very small grains, or from molecules consisting of 10-100 carbon atoms, which have been excited by ultraviolet radiation from the illuminating stars.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 313; 853-858
    Format: text
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    NASA TECHNICAL REPORTS
  • 17
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    IRAS surface brightness maps of visible reflection nebulae: Evidence for non-equilibrium infrared emission (1986)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Surface brightness maps at 12, 25, 60, and 100 microns of 16 visible reflection nebulae were extracted from the Infrared Astronomy Satellite (IRAS) database. The maps were produced by coadding IRAS survey scans over areas centered on the illuminating stars, and have spatial resolutions of 0.9' x 4' at 12 and 25 microns, 1.8' x 4.5' at 60 microns, and 3.6' x 5' at 100 microns. Extended emission in the four IRAS bandpasses was detected in fourteen of the reflection nebulae. The IRAS data were used to measure the flux of the infrared emission associated with each source. The energy distributions show that the 12 micron flux is greater than the 25 micron flux in 11 of the nebulae, and the peak flux occurs in the 60 or 100 micron bandpass in all 16 nebular. The 60 and 100 micron flux can be approximated by blackbodies with temperatures between 30 and 50 K, consistent with temperatures expected from extrapolation of greybody fits to the 60 and 100 micron data. The excess 12 and 25 micron emission is attributed to a nonequilibrium process such as emission from thermal fluctuations of very small grains excited by single ultraviolet photons, or emission from polycyclic aromatic hydrocarbons (PAHs) excited by ultraviolet radiation. The common features of the energy distributions of the 16 reflection nebulae, also seen in the reflection nebulae associated with the Pleiades, suggest that PAHs or very small grains may be found in most reflection nebulae.
    Keywords: ASTROPHYSICS
    Type: Summer School on Interstellar Processes: Abstracts of Contributed Papers; p 121
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 18
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    Emission features in the 4-13 micron spectra of the reflection nebulae NGC 7023 and NGC 2023 (1985)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Spectroscopy from 4 to 13 microns of the visual reflection nebulae NGC 7023 and NGC 2023 has been obtained. These data, together with previous work from 1 to 4 microns, show that the spectra of these sources consist of a relatively flat continuum from 1 to 13 microns and six emission features at 3.3, 3.4, 6.2, 7.7, 8.6, and 11.3 microns. The observations rule out equilibrium thermal emission for the features and continuum in reflection nebulae, and point toward a nonequilibrium emission mechanism such as thermal emission from thermally fluctuating small grains or fluorescence from large molecules. The similarity of the emission feature spectra in reflection nebulae to those in other sources suggests a universal emission mechanism, thus implying nonequilibrium emission mechanisms in other sources.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 299; 416-423
    Format: text
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    NASA TECHNICAL REPORTS
  • 19
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    Space infrared telescope facility (SIRTF) focal plane (1986)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The Infrared Array Camera (IRAC), Multiband Imaging Photometer (MIP), and the Infrared Spectrometer (IRS) of the Space Infrared Telescope Facility (SIRTF) are described. The configuration and capabilities of the SIRTF are discussed. The small silicon array module, the germanium array module, and bolometer module of MIP, which is designed to provide sensitivity limited only by natural background and telescope emissions over the 3-200 micron spectral range, and allow diffraction limited imaging, super resolution techniques, mapping, and surveying, are examined. The objectives and design of the IRAC, which is constructed for two-dimensional photometry and imaging over a wavelength region from 2-30 microns and to perform extragalactic, galactic and solar system astronomy, are studied. The use of the IRS to study the dynamical and physical phenomena of the universe in the 2.5-200 micron range is analyzed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA PAPER 86-0373
    Format: text
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    NASA TECHNICAL REPORTS
  • 20
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    Extreme limb profiles of the sun at far-infrared and submillimeter wavelengths (1986)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Thirty, 50, 100, and 200 microns solar limb intensity profiles determined with arcsecond resolution from airborne observations of the occultation of the solar limb during the total eclipse of 1981 July 31 are presented. Two points of particular importance emerge: (1) the longer-wavelength (100 and 200 micron) limbs are significantly brighter than disk center. At 200 microns the extreme limb is about 1.22 times the brightness of disk center. This is consistent with the 6000 K temperature-plateau structure of the model chromospheres of Vernazza, Avrett, and Loeser (1973, Ap. J., 184, 605; 1981; Ap. J. Suppl., 45, 635;) and (2) the longer wavelength limbs are extended significantly further above the visible limb than Vernazza, Avrett, and Loeser predict. These results provide a strong basis for modeling of the solar chromosphere free from the assumption of gravitational-hydrostatic equilibrium.
    Keywords: ASTRONOMY
    Type: NASA-TM-88251 , A-86236 , NAS 1.15:88251
    Format: application/pdf
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