Infrared Emission from the Smallest Active Galaxies

NASA Astrophysics Data System (ADS)

Barth, Aaron; Greene, Jenny; Ho, Luis

2006-05-01

Virtually all of our current knowledge of black hole demographics, both in nearby inactive galaxies and in AGNs, comes from observations of black holes with masses between a few million and a few billion solar masses in host galaxies with stellar velocity dispersions between about 70 and 400 km/sec. Searching for smaller black holes in low-mass galaxies can yield important clues to the origin and early evolution of supermassive black holes, and AGN surveys are the best available way to identify such objects. Using the Sloan Digital Sky Survey, we have identified 19 Seyfert 1 galaxies with black hole mass below 10^6 solar masses (Greene & Ho 2004), and 20 Seyfert 2 galaxies having stellar velocity dispersions smaller than 70 km/sec as determined by new Keck observations. These AGN samples offer a unique opportunity to study the very early growth stages of black holes and their host galaxies. Spitzer observations of mid-infrared emission will be the best available calorimeter of the energetics of these tiny AGNs. Our primary goal is to determine the infrared contribution to the bolometric luminosities, which will be a key to understanding the black hole accretion rates. From the infrared spectral shapes we will constrain the dust temperatures and search for silicate features in emission or absorption that may indicate the presence of an obscuring torus, and which will help to determine whether the Type 1 and Type 2 objects differ primarily as a result of our viewing angle, as in classic AGN unified models. PAH features and narrow emission lines will be used to diagnose the relative contributions of AGN and star formation to the infrared luminosity. To accomplish these goals, we request IRS staring-mode spectroscopy in the SL2, SL1, LL2, and LL1 settings for our Sloan-selected sample of 19 Seyfert 1s and 20 Seyfert 2s, as well as NGC 4395 and POX 52, which are the prototypical nearby examples of Seyfert nuclei in dwarf host galaxies.

Nacre biomimetic design--a possible approach to prepare low infrared emissivity composite coatings.

PubMed

Zhang, Weigang; Xu, Guoyue; Ding, Ruya; Duan, Kaige; Qiao, Jialiang

2013-01-01

Mimicking the highly organized brick-and-mortar structure of nacre, a kind of nacre-like organic-inorganic composite material of polyurethane (PU)/flaky bronze composite coatings with low infrared emissivity was successfully designed and prepared by using PU and flaky bronze powders as adhesives and pigments, respectively. The infrared emissivity and microstructure of the coatings were systematically investigated by infrared emissometer and scanning electron microscopy, respectively, and the cause of low infrared emissivity of the coatings was discussed by using the theories of one-dimensional photonic structure. The results show that the infrared emissivity of the nacre-like PU/flaky bronze composite coatings can be as low as 0.206 at the bronze content of 60 wt. %, and it is significantly lower than the value of PU/sphere bronze composite coatings. Microstructure observation illustrated that the nacre-like PU/flaky bronze composite coatings have similar one-dimensional photonic structural characteristics. The low infrared emissivity of PU/flaky bronze composite coatings is derived from the similar one-dimensional photonic structure in the coatings. Copyright © 2012 Elsevier B.V. All rights reserved.

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.

Far-Infrared Line Emission from High Redshift Quasars

NASA Technical Reports Server (NTRS)

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

2002-01-01

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

Infrared Space Observatory Observations of Far-Infrared Rotational Emission Lines of Water Vapor Toward the Supergiant Star VY Canis Majoris

NASA Technical Reports Server (NTRS)

Neufeld, David A.; Feuchtgruber, Helmut; Harwit, Martin; Melnick, Gary J.

1999-01-01

We report the detection of numerous far-infrared emission lines of water vapor toward the supergiant star VY Canis Majoris. A 29.5-45 micron grating scan of VY CMa, obtained using the Short-Wavelength Spectrometer (SWS) of the Infrared Space Observatory at a spectral resolving power lambda/delat.lambda of approximately 2000, reveals at least 41 spectral features due to water vapor that together radiate a total luminosity of approximately 25 solar luminosity . In addition to pure rotational transitions within the ground vibrational state, these features include rotational transitions within the (010) excited vibrational state. The spectrum also shows the (sup 2)product(sub 1/2) (J = 5/2) left arrow (sup 2)product(sub 3/2) (J = 3/2) OH feature near 34.6 micron in absorption. Additional SWS observations of VY CMa were carried out in the instrument's Fabry-Perot mode for three water transitions: the 7(sub 25)-6(sub 16) line at 29.8367 micron, the 4(sub 41)-3(sub 12) line at 31.7721 micron, and the 4(sub 32)-3(sub 03) line at 40.6909 micron. The higher spectral resolving power lambda/delta.lambda of approximately 30,000 thereby obtained permits the line profiles to be resolved spectrally for the first time and reveals the "P Cygni" profiles that are characteristic of emission from an outflowing envelope.

Sensitive observations with the Spacelab 2 infrared telescope

NASA Technical Reports Server (NTRS)

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.

1983-01-01

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.

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.

Time-dependent infrared emission following photodissociation of nitromethane and chloropicrin.

PubMed

Wade, Elisabeth A; Reak, Kristina E; Li, Sissi L; Clegg, Samuel M; Zou, Peng; Osborn, David L

2006-04-06

Nitromethane (CH(3)NO(2)) and its chlorinated analogue, chloropicrin (CCl(3)NO(2)), were photolyzed at 193, 248, and 266 nm, and the products were observed by time-dependent Fourier transform infrared emission spectroscopy. At 193 and 248 nm, the primary photodissociation pathway for nitromethane was cleavage of the C-N bond to produce CH(3) + NO(2)(A (2)B(2)). At 266 nm, weak emission was observed following photodissociation of nitromethane, but an infrared spectrum could not be obtained. The photodissociation of chloropicrin at 193 nm produced the analogous product channel CCl(3) + NO(2)(A (2)B(2)) in addition to several other product channels. At 248 and 266 nm, only CCl(3) + NO(2)(A (2)B(2)) was observed. The production of phosgene (CCl(2)O) from chloropicrin photodissociation was not observed in this study.

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.

Mid-Infrared Ethane Emission on Neptune: 2005-2009

NASA Astrophysics Data System (ADS)

Hammel, Heidi B.; Sitko, M. L.; Russell, R. W.; Lynch, D. K.; Bernstein, L. S.; Perry, R. B.

2009-09-01

Hammel et al. (2006, ApJ 644, 1326) reported 8- to 13-micron spectral observations of Neptune spanning more than a decade. Those data indicated a steady increase in Neptune's 12-micron atmospheric ethane emission from 1985 to 2003, followed by a slight decrease in 2004. The simplest explanation for the intensity variation was an increase in stratospheric effective temperature from 155 K in 1985 to 176 K in 2003 (an average rate of 1.2 K/year), and subsequent decrease to 165 K in 2004 (uncertainties +/- 3 K). Later disk-resolved 12-micron images (Hammel et al. 2007, AJ 134, 637; Orton et al. 2007, AA 473, L5) showed Neptune's ethane emission arose mainly from two regions: emission distributed nearly uniformly around the planet's limb and emission near the south pole. Because much of the non-limb emission was confined to the near-polar region, seasonal variation may play some role in the long-term mid-infrared brightness variations: i.e., more of that region was revealed as Neptune neared solstice in 2005. We will report the results of an additional half decade of mid-infrared spectroscopic observations, from 2005 through 2009, using the Broadband Array Spectrograph System on the NASA Infrared Telescope Facility (IRTF). These post-solstice data should elucidate whether the variations are intrinsic, or due to changes in viewing angle. HBH acknowledges support from NASA grants NNX06AD12G and NNA07CN65A. This work was supported at The Aerospace Corporation by the Independent Research and Development Program. LSB acknowledges the support of Spectral Sciences, Inc. IR and D funding. We also gratefully acknowledge D. Kim (The Aerospace Corporation) for BASS technical support, as well as the support of IRTF staff and telescope operators. We recognize the significant cultural role of Mauna Kea within the indigenous Hawaiian community, and we appreciate the opportunity to conduct observations from this revered site.

New Infrared Emission Features and Spectral Variations in Ngc 7023

NASA Technical Reports Server (NTRS)

Werner, M. W.; Uchida, K. I.; Sellgren, K.; Marengo, M.; Gordon, K. D.; Morris, P. W.; Houck, J. R.; Stansberry, J. A.

2004-01-01

We observed the reflection nebula NGC 7023, with the Short-High module and the long-slit Short-Low and Long-Low modules of the Infrared Spectrograph on the Spitzer Space Telescope. We also present Infrared Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS) images of NGC 7023 at 3.6, 4.5, 8.0, and 24 m. We observe the aromatic emission features (AEFs) at 6.2, 7.7, 8.6, 11.3, and 12.7 m, plus a wealth of weaker features. We find new unidentified interstellar emission features at 6.7, 10.1, 15.8, 17.4, and 19.0 m. Possible identifications include aromatic hydrocarbons or nanoparticles of unknown mineralogy. We see variations in relative feature strengths, central wavelengths, and feature widths, in the AEFs and weaker emission features, depending on both distance from the star and nebular position (southeast vs. northwest).

Infrared emission spectra of candidate interstellar aromatic molecules

NASA Technical Reports Server (NTRS)

Schlemmer, S.; Balucani, N.; Wagner, D. R.; Steiner, B.; Saykally, R. J.

1996-01-01

Interstellar dust is responsible, through surface reactions, for the creation of molecular hydrogen, the main component of the interstellar clouds in which new stars form. Intermediate between small, gas-phase molecules and dust are the polycyclic aromatic hydrocarbons (PAHs). Such molecules could account for 2-30% of the carbon in the Galaxy, and may provide nucleation sites for the formation of carbonaceous dust. Although PAHs have been proposed as the sources of the unidentified infrared emission bands that are observed in the spectra of a variety of interstellar sources, the emission characteristics of such molecules are still poorly understood. Here we report laboratory emission spectra of several representative PAHs, obtained in conditions approximating those of the interstellar medium, and measured over the entire spectral region spanned by the unidentified infrared bands. We find that neutral PAHs of small and moderate size can at best make only a minor contribution to these emission bands. Cations of these molecules, as well as much larger PAHs and their cations, remain viable candidates for the sources of these bands.

Mid-infrared, long wave infrared (4-12 μm) molecular emission signatures from pharmaceuticals using laser-induced breakdown spectroscopy (LIBS).

PubMed

Yang, Clayton S-C; Brown, Ei E; Kumi-Barimah, Eric; Hommerich, Uwe H; Jin, Feng; Trivedi, Sudhir B; Samuels, Alan C; Snyder, A Peter

2014-01-01

In an effort to augment the atomic emission spectra of conventional laser-induced breakdown spectroscopy (LIBS) and to provide an increase in selectivity, mid-wave to long-wave infrared (IR), LIBS studies were performed on several organic pharmaceuticals. Laser-induced breakdown spectroscopy signature molecular emissions of target organic compounds are observed for the first time in the IR fingerprint spectral region between 4-12 μm. The IR emission spectra of select organic pharmaceuticals closely correlate with their respective standard Fourier transform infrared spectra. Intact and/or fragment sample molecular species evidently survive the LIBS event. The combination of atomic emission signatures derived from conventional ultraviolet-visible-near-infrared LIBS with fingerprints of intact molecular entities determined from IR LIBS promises to be a powerful tool for chemical detection.

Infrared coronal emission lines and the possibility of their maser emission in Seyfert nuclei

NASA Technical Reports Server (NTRS)

Greenhouse, Matthew A.; Feldman, Uri; Smith, Howard A.; Klapisch, Marcel; Bhatia, Anand K.; Bar-Shalom, Abi

1993-01-01

Energetic emitting regions have traditionally been studied via x-ray, UV and optical emission lines of highly ionized intermediate mass elements. Such lines are often referred to as 'coronal lines' since the ions, when produced by collisional ionization, reach maximum abundance at electron temperatures of approx. 10(exp 5) - 10(exp 6) K typical of the sun's upper atmosphere. However, optical and UV coronal lines are also observed in a wide variety of Galactic and extragalactic sources including the Galactic interstellar medium, nova shells, supernova remnants, galaxies and QSOs. Infrared coronal lines are providing a new window for observation of energetic emitting regions in heavily dust obscured sources such as infrared bright merging galaxies and Seyfert nuclei and new opportunities for model constraints on physical conditions in these sources. Unlike their UV and optical counterparts, infrared coronal lines can be primary coolants of collisionally ionized plasmas with 10(exp 4) less than T(sub e)(K) less than 10(exp 6) which produce little or no optical or shorter wavelength coronal line emission. In addition, they provide a means to probe heavily dust obscured emitting regions which are often inaccessible to optical or UV line studies. In this poster, we provide results from new model calculations to support upcoming Infrared Space Observatory (ISO) and current ground-based observing programs involving infrared coronal emission lines in AGN. We present a complete list of infrared (lambda greater than 1 micron) lines due to transitions within the ground configurations 2s(2)2p(k) and 3s(2)3p(k) (k = 1 to 5) or the first excited configurations 2s2p and 3s3p of highly ionized (x greater than or equal to 100 eV) astrophysically abundant (n(X)/n(H) greater than or equal to 10(exp -6)) elements. Included are approximately 74 lines in ions of O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, and Ni spanning a wavelength range of approximately 1 - 280 microns. We present new

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.

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.

Transient Infrared Emission Spectroscopy

NASA Astrophysics Data System (ADS)

Jones, Roger W.; McClelland, John F.

1989-12-01

Transient Infrared Emission Spectroscopy (TIRES) is a new technique that reduces the occurrence of self-absorption in optically thick solid samples so that analytically useful emission spectra may be observed. Conventional emission spectroscopy, in which the sample is held at an elevated, uniform temperature, is practical only for optically thin samples. In thick samples the emission from deep layers of the material is partially absorbed by overlying layers.1 This self-absorption results in emission spectra from most optically thick samples that closely resemble black-body spectra. The characteristic discrete emission bands are severely truncated and altered in shape. TIRES bypasses this difficulty by using a laser to heat only an optically thin surface layer. The increased temperature of the layer is transient since the layer will rapidly cool and thicken by thermal diffusion; hence the emission collection must be correlated with the laser heating. TIRES may be done with both pulsed and cw lasers.2,3 When a pulsed laser is used, the spectrometer sampling must be synchronized with the laser pulsing so that only emission during and immediately after each laser pulse is observed.3 If a cw laser is used, the sample must move rapidly through the beam. The hot, transient layer is then in the beam track on the sample at and immediately behind the beam position, so the spectrometer field of view must be limited to this region near the beam position.2 How much self-absorption the observed emission suffers depends on how thick the heated layer has grown by thermal diffusion when the spectrometer samples the emission. Use of a pulsed laser synchronized with the spectrometer sampling readily permits reduction of the time available for heat diffusion to about 100 acs .3 When a cw laser is used, the heat-diffusion time is controlled by how small the spectrometer field of view is and by how rapidly the sample moves past within this field. Both a very small field of view and a

Modelling of mid-infrared interferometric signature of hot exozodiacal dust emission

NASA Astrophysics Data System (ADS)

Kirchschlager, Florian; Wolf, Sebastian; Brunngräber, Robert; Matter, Alexis; Krivov, Alexander V.; Labdon, Aaron

2018-01-01

Hot exozodiacal dust emission was detected in recent surveys around two dozen main-sequence stars at distances of less than 1 au using the H- and K-band interferometry. Due to the high contrast as well as the small angular distance between the circumstellar dust and the star, direct observation of this dust component is challenging. An alternative way to explore the hot exozodiacal dust is provided by mid-infrared interferometry. We analyse the L, M and N bands interferometric signature of this emission in order to find stronger constraints for the properties and the origin of the hot exozodiacal dust. Considering the parameters of nine debris disc systems derived previously, we model the discs in each of these bands. We find that the M band possesses the best conditions to detect hot dust emission, closely followed by L and N bands. The hot dust in three systems - HD 22484 (10 Tau), HD 102647 (β Leo) and HD 177724 (ζ Aql) - shows a strong signal in the visibility functions, which may even allow one to constrain the dust location. In particular, observations in the mid-infrared could help to determine whether the dust piles up at the sublimation radius or is located at radii up to 1 au. In addition, we explore observations of the hot exozodiacal dust with the upcoming mid-infrared interferometer Multi AperTure mid-Infrared SpectroScopic Experiment (MATISSE) at the Very Large Telescope Interferometer.

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.

Auroral nitric oxide concentration and infrared emission

NASA Astrophysics Data System (ADS)

Reidy, W. P.; Degges, T. C.; Hurd, A. G.; Stair, A. T., Jr.; Ulwick, J. C.

1982-05-01

Rocket-borne measurements of infrared auroral emission by nitric oxide are analyzed. Four rocket flights provided opportunities to measure 5.3- and 2.7-micron NO emission by means of infrared fixed band radiometers and CVF spectrometers, narrow band photometers, and incident energy spectra on various occasions. Analysis of infrared emission profiles and electron flux data indicates the NO density to be significantly enhanced with respect to midlatitude values. NO emission in the fundamental 5.3-micron band is attributed to resonance excitation by warm earth radiation, collisional excitation primarily by O atoms and chemiluminescence from the reaction of N with O2; with an energy efficiency of 0.015. The overtone band emission at 2.7 microns is accounted for by chemiluminescence produced with an energy efficiency of 0.0054. Total photon yield for the chemiluminescence reaction is estimated to range from 1.2 to 2.4 vibrational quanta per NO molecule.

Infrared Measurements of the Emissivity of Seawater and Foam

NASA Astrophysics Data System (ADS)

Branch, R.; Chickadel, C.; Jessup, A.; Carini, R. J.

2012-12-01

The emissivity of water has been modeled extensively in the infrared (IR) from 2-14 μm for incidence angles from 0-85° [Masuda et al. 1988, Shaw & Marston 2000, Nalli et al. 2001] but very few measurements have been published for grazing incidence angles, wavelengths from 3-5 μm, or of sea foam. Grazing incidence angles are commonly used for ship and shore based operations as well as sea surface scene simulation. Overall, water emissivity models predict a steep decline at for angles greater than 60 degrees [Masuda et al. 1988], while sea foam maintains a higher emissivity [Niclos et al. 2007]. Emissivity of foam has also been found to be smaller than water at mid-wave IR wavelengths and small incidence angles [Salisbury et al. 1993]. Further complication arises from the observations that foam from actively breaking waves appears warmer than surrounding water [Eisner et al. 1962], but residual foam appears cooler [Marmorino and Smith, 2005]. Here we present measurements of emissivity at grazing incidence angles (up to 87.5 degrees incidence) of natural seawater and sea foam. Our measurements are made using a Fourier-transform infrared (FTIR) spectrometer observing under both natural skies and laboratory conditions. In a laboratory wind tunnel we plan to test the effect of varying heat flux on the formation of cooling foam, by varying surface wind speed. Results will be compared with existing spectral emissivity models for water and foam.

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

PubMed Central

Jackson, Michael; Zink, Lyndon R.

2015-01-01

The generation and subsequent measurement of far-infrared radiation has found numerous applications in high-resolution spectroscopy, radio astronomy, and Terahertz imaging. For about 45 years, the generation of coherent, far-infrared radiation has been accomplished using the optically pumped molecular laser. Once far-infrared laser radiation is detected, the frequencies of these laser emissions are measured using a three-laser heterodyne technique. With this technique, the unknown frequency from the optically pumped molecular laser is mixed with the difference frequency between two stabilized, infrared reference frequencies. These reference frequencies are generated by independent carbon dioxide lasers, each stabilized using the fluorescence signal from an external, low pressure reference cell. The resulting beat between the known and unknown laser frequencies is monitored by a metal-insulator-metal point contact diode detector whose output is observed on a spectrum analyzer. The beat frequency between these laser emissions is subsequently measured and combined with the known reference frequencies to extrapolate the unknown far-infrared laser frequency. The resulting one-sigma fractional uncertainty for laser frequencies measured with this technique is ± 5 parts in 107. Accurately determining the frequency of far-infrared laser emissions is critical as they are often used as a reference for other measurements, as in the high-resolution spectroscopic investigations of free radicals using laser magnetic resonance. As part of this investigation, difluoromethane, CH2F2, was used as the far-infrared laser medium. In all, eight far-infrared laser frequencies were measured for the first time with frequencies ranging from 0.359 to 1.273 THz. Three of these laser emissions were discovered during this investigation and are reported with their optimal operating pressure, polarization with respect to the CO2 pump laser, and strength. PMID:26709957

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

PubMed

Jackson, Michael; Zink, Lyndon R

2015-12-18

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

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.

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

NASA Astrophysics Data System (ADS)

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

2017-06-01

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

Infrared emission of a freestanding plasmonic membrane

NASA Astrophysics Data System (ADS)

Monshat, Hosein; Liu, Longju; McClelland, John; Biswas, Rana; Lu, Meng

2018-01-01

This paper reports a free-standing plasmonic membrane as a thermal emitter in the near- and mid-infrared regions. The plasmonic membrane consists of an ultrathin gold film perforated with a two-dimensional array of holes. The device was fabricated using an imprint and transfer process and fixed on a low-emissivity metal grid. The thermal radiation characteristics of the plasmonic membrane can be engineered by controlling the array period and the thickness of the gold membrane. Plasmonic membranes with two different periods were designed using electromagnetic simulation and then characterized for their transmission and infrared radiation properties. The free-standing membranes exhibit extraordinary optical transmissions with the resonant transmission coefficient as high as 76.8%. After integration with a customized heater, the membranes demonstrate narrowband thermal emission in the wavelength range of 2.5 μm to 5.5 μm. The emission signatures, including peak emission wavelength and bandwidth, are associated with the membrane geometry. The ultrathin membrane infrared emitter can be adopted in applications, such as chemical analysis and thermal imaging.

Near-infrared Spectroscopic Observations of Comet C/2013 R1 (Lovejoy) by WINERED: CN Red-system Band Emission

NASA Astrophysics Data System (ADS)

Shinnaka, Yoshiharu; Kawakita, Hideyo; Kondo, Sohei; Ikeda, Yuji; Kobayashi, Naoto; Hamano, Satoshi; Sameshima, Hiroaki; Fukue, Kei; Matsunaga, Noriyuki; Yasui, Chikako; Izumi, Natsuko; Mizumoto, Misaki; Otsubo, Shogo; Takenaka, Keiichi; Watase, Ayaka; Kawanishi, Takafumi; Nakanishi, Kenshi; Nakaoka, Tetsuya

2017-08-01

Although high-resolution spectra of the CN red-system band are considered useful in cometary sciences, e.g., in the study of isotopic ratios of carbon and nitrogen in cometary volatiles, there have been few reports to date due to the lack of high-resolution (R ≡ λ/Δλ > 20,000) spectrographs in the near-infrared region around ˜1 μm. Here, we present the high-resolution emission spectrum of the CN red-system band in comet C/2013 R1 (Lovejoy), acquired by the near-infrared high-resolution spectrograph WINERED mounted on the 1.3 m Araki telescope at the Koyama Astronomical Observatory, Kyoto, Japan. We applied our fluorescence excitation models for CN, based on modern spectroscopic studies, to the observed spectrum of comet C/2013 R1 (Lovejoy) to search for CN isotopologues (13C14N and 12C15N). We used a CN fluorescence excitation model involving both a “pure” fluorescence excitation model for the outer coma and a “fully collisional” fluorescence excitation model for the inner coma region. Our emission model could reproduce the observed 12C14N red-system band of comet C/2013 R1 (Lovejoy). The derived mixing ratio between the two excitation models was 0.94(+0.02/-0.03):0.06(+0.03/-0.02), corresponding to the radius of the collision-dominant region of ˜800-1600 km from the nucleus. No isotopologues were detected. The observed spectrum is consistent, within error, with previous estimates in comets of 12C/13C (˜90) and 14N/15N (˜150).

Single photon infrared emission spectroscopy: a study of IR emission from UV laser excited PAHs between 3 and 15 micrometers

NASA Technical Reports Server (NTRS)

Cook, D. J.; Schlemmer, S.; Balucani, N.; Wagner, D. R.; Harrison, J. A.; Steiner, B.; Saykally, R. J.

1998-01-01

Single-photon infrared emission spectroscopy (SPIRES) has been used to measure emission spectra from polycyclic aromatic hydrocarbons (PAHs). A supersonic free-jet expansion has been used to provide emission spectra of rotationally cold and vibrationally excited naphthalene and benzene. Under these conditions, the observed width of the 3.3-micrometers (C-H stretch) band resembles the bandwidths observed in experiments in which emission is observed from naphthalene with higher rotational energy. To obtain complete coverage of IR wavelengths relevant to the unidentified infrared bands (UIRs), UV laser-induced desorption was used to generate gas-phase highly excited PAHs. Lorentzian band shapes were convoluted with the monochromator-slit function in order to determine the widths of PAH emission bands under astrophysically relevant conditions. Bandwidths were also extracted from bands consisting of multiple normal modes blended together. These parameters are grouped according to the functional groups mostly involved in the vibration, and mean bandwidths are obtained. These bandwidths are larger than the widths of the corresponding UIR bands. However, when the comparison is limited to the largest PAHs studied, the bandwidths are slightly smaller than the corresponding UIR bands. These parameters can be used to model emission spectra from PAH cations and cations of larger PAHs, which are better candidate carriers of the UIRs.

Apparatus and method for transient thermal infrared emission spectrometry

DOEpatents

McClelland, John F.; Jones, Roger W.

1991-12-24

A method and apparatus for enabling analysis of a solid material (16, 42) by applying energy from an energy source (20, 70) top a surface region of the solid material sufficient to cause transient heating in a thin surface layer portion of the solid material (16, 42) so as to enable transient thermal emission of infrared radiation from the thin surface layer portion, and by detecting with a spectrometer/detector (28, 58) substantially only the transient thermal emission of infrared radiation from the thin surface layer portion of the solid material. The detected transient thermal emission of infrared radiation is sufficiently free of self-absorption by the solid material of emitted infrared radiation, so as to be indicative of characteristics relating to molecular composition of the solid material.

Jupiter's auroral-related thermal infrared emission from IRTF-TEXES

NASA Astrophysics Data System (ADS)

Sinclair, James; Orton, Glenn; Greathouse, Thomas; Fletcher, Leigh; Irwin, Patrick

2015-11-01

Auroral processes on Jupiter can be observed at a large range of wavelengths. Charged particles of the solar wind are deflected by Jupiter’s magnetic field and penetrate the atmosphere at high latitudes. This results in ion and/or electron precipitation, which produces emission at X-ray, UV, visible, near-infrared and even radio wavelengths. These observations indicate three distinct features of the aurora: 1) filament-like oval structures fixed at the magnetic poles (~80°W (System III) in the south, ~180°W in the north), 2) spatially-continuous but transient aurora that fill these oval regions and 3) discrete spots associated with the magnetic footprints of Io and other Galilean satellites. However, observations in the thermal infrared indicate the aurora also modify the neutral atmosphere. Enhanced emission of CH4 is observed coincident with the auroral ovals and indicates heightened stratospheric temperatures possibly as a result of joule heating by the influx of charged particles. Stronger emission is also observed of C2H2, C2H4, C2H6 and even C6H6 though previous work has struggled to determine whether this is a temperature or compositional effect. In order to quantify the auroral effects on the neutral atmosphere and to support the 2016 Juno mission (which has no thermal infrared instrument) we have performed a retrieval analysis of IRTF-TEXES (Texas Echelon Cross Echelle Spectrograph, 5- to 25-μm) spectra obtained on Dec 11th 2014 near solar maximum. The instrument slit was scanned east-west across high latitudes in each hemisphere and Jupiter’s rotation was used to obtain ~360° longitudinal coverage. Spectra of H2 S(1), CH4, C2H2, C2H4 and C2H6 emission were measured at a resolving power of R = 85000, allowing a large vertical range in the atmosphere (100 - 0.001 mbar) to be sounded. Preliminary retrievals of the vertical temperature profile from H2 S(1) and CH4 measurements at 60°N, 180°W (on aurora), in comparison to 60°N, 60°W (quiescent

Effect of boron on enhancing infrared emissivity of Ni-Cr system coating

NASA Astrophysics Data System (ADS)

Li, Yongjia; Ouyang, Taoyuan; Wang, Xiaohuan; Li, Shuhao; Mao, Jiawei; Cheng, Xudong

2018-03-01

High infrared emissivity coating possesses great value in practical application, whether in the military or civilian areas. In this study, B-NiCr precursor powder containing NiO, Cr2O3 and ZrB2 was calcined at 1300 °C and then used to prepare a high infrared emissivity B-NiCr coating via atmospheric plasma spraying. A large number of test methods were employed to analyze the powder and coating, including TG-DSC, XRD, FE-SEM, infrared spectrometer and so on. The result of infrared emissivity measurement indicates that the coating possesses maximum infrared emissivity of 0.908 at 1000 °C while the infrared emissivity is 0.901 after thermal shock test. Comparing with NiCr coating, Ni2CrO2(BO3) formed during calcination may be the main factor to improve the infrared emissivity of B-NiCr coating. The B-NiCr coating possesses good thermal shock resistance and can withstand 50 times thermal shock at least without falling off, from 800 °C to room temperature.

Near-infrared Spectroscopic Observations of Comet C/2013 R1 (Lovejoy) by WINERED: CN Red-system Band Emission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shinnaka, Yoshiharu; Yasui, Chikako; Izumi, Natsuko

Although high-resolution spectra of the CN red-system band are considered useful in cometary sciences, e.g., in the study of isotopic ratios of carbon and nitrogen in cometary volatiles, there have been few reports to date due to the lack of high-resolution ( R  ≡  λ /Δ λ  > 20,000) spectrographs in the near-infrared region around ∼1 μ m. Here, we present the high-resolution emission spectrum of the CN red-system band in comet C/2013 R1 (Lovejoy), acquired by the near-infrared high-resolution spectrograph WINERED mounted on the 1.3 m Araki telescope at the Koyama Astronomical Observatory, Kyoto, Japan. We applied our fluorescence excitation models for CN, based onmore » modern spectroscopic studies, to the observed spectrum of comet C/2013 R1 (Lovejoy) to search for CN isotopologues ({sup 13}C{sup 14}N and {sup 12}C{sup 15}N). We used a CN fluorescence excitation model involving both a “pure” fluorescence excitation model for the outer coma and a “fully collisional” fluorescence excitation model for the inner coma region. Our emission model could reproduce the observed {sup 12}C{sup 14}N red-system band of comet C/2013 R1 (Lovejoy). The derived mixing ratio between the two excitation models was 0.94(+0.02/−0.03):0.06(+0.03/−0.02), corresponding to the radius of the collision-dominant region of ∼800–1600 km from the nucleus. No isotopologues were detected. The observed spectrum is consistent, within error, with previous estimates in comets of {sup 12}C/{sup 13}C (∼90) and {sup 14}N/{sup 15}N (∼150).« less

Infrared and infrared emission spectroscopy of gallium oxide alpha-GaO(OH) nanostructures.

PubMed

Yang, Jing Jeanne; Zhao, Yanyan; Frost, Ray L

2009-10-01

Infrared spectroscopy has been used to study nano- to micro-sized gallium oxyhydroxide alpha-GaO(OH), prepared using a low temperature hydrothermal route. Rod-like alpha-GaO(OH) crystals with average length of approximately 2.5 microm and width of 1.5 microm were prepared when the initial molar ratio of Ga to OH was 1:3. beta-Ga(2)O(3) nano and micro-rods were prepared through the calcination of alpha-GaO(OH). The initial morphology of alpha-GaO(OH) is retained in the beta-Ga(2)O(3) nanorods. The combination of infrared and infrared emission spectroscopy complimented with dynamic thermal analysis were used to characterise the alpha-GaO(OH) nanotubes and the formation of beta-Ga(2)O(3) nanorods. Bands at around 2903 and 2836 cm(-1) are assigned to the -OH stretching vibration of alpha-GaO(OH) nanorods. Infrared bands at around 952 and 1026 cm(-1) are assigned to the Ga-OH deformation modes of alpha-GaO(OH). A significant number of bands are observed in the 620-725 cm(-1) region and are assigned to GaO stretching vibrations.

Mid-Infrared Spectrum of the Zodiacal Emission: Detection of Crystalline Silicates in Interplanetary Dust

NASA Technical Reports Server (NTRS)

Ootsubo, T.; Onaka, T.; Yamamura, I.; Ishihara, D.; Tanabe, T.; Roellig, T. L.

2003-01-01

Within a few astronomical units of the Sun the solar system is filled with interplanetary dust, which is believed to be dust of cometary and asteroidal origin. Spectroscopic observations of the zodiacal emission with moderate resolution provide key information on the composition and size distribution of the dust in the interplanetary space. They can be compared directly to laboratory measurements of candidate materials, meteorites, and dust particles collected in the stratosphere. Recently mid-infrared spectroscopic observations of the zodiacal emission have been made by two instruments on board the Infrared Space Observatory; the camera (ISOCAM) and the spectrophotometer (ISOPHOT-S). A broad excess emission feature in the 9-11 micron range is reported in the ISOCAM spectrum, whereas the ISOPHOT-S spectra in 6-12 microns can be well fitted by a blackbody radiation without spectral features.

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.

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.

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.

EVLA Observation of Centimeter Continuum Emission from Protostars in Serpens South

NASA Astrophysics Data System (ADS)

Kern, Nicholas S.; Tobin, John J.; Keown, Jared A.; Gutermuth, Robert A.

2015-01-01

Serpens South is a protocluster with an unusually high abundance of Class 0 and I protostars, suggesting it is in a very early phase of star formation and may eventually form a star cluster. Following its discovery in 2008 with the Spitzer space telescope, infrared and millimeter observations and analysis quickly followed, however, Serpens South has yet to be fully explored in the radio. Radio observations at centimeter wavelengths have long been used as a tool to probe the dynamical processes of young protostars that are still heavily shrouded in their protostellar envelopes and thus cannot be seen at longer wavelengths. Radio observations then become an important tool in understanding Serpens South due to its young age. To this end, we have conducted EVLA C band continuum observations of the central region of the Serpens South protostellar cluster in order to map the centimeter continuum emission in a region of high Class 0 / I protostellar surface density. We report the detection of centimeter emission corresponding to protostars identified by Spitzer, and to protostars identified but blended by Herschel. We characterize their centimeter emission, and put them in context with previous Spitzer and Herschel infrared and far-infrared observations, as well as IRAM millimeter observations. Additionally, we make an assessment of the protostars' bolometric luminosity, and compare them to the known protostellar 3.6 cm to 6.0 cm luminosity vs. bolometric luminosity relation. With the EVLA, we present a mid-resolution map of centimeter emission from the central region of Serpens South with the highest sensitivity to date, with a beam size of ~5 arcseconds and rms on the order of 15 microJansky.

The near-infrared continuum emission of visual reflection nebulae

NASA Technical Reports Server (NTRS)

Sellgren, K.

1984-01-01

In the past, reflection nebulae have provided an astrophysical laboratory well suited for the study of the reflection properties of interstellar dust grains at visual and ultraviolet wavelengths. The present investigation is concerned with observations which were begun with the objective to extend to near-infrared wavelengths the study of grains in reflection. Observations of three classical visual reflection nebulae were conducted in the wavelength range from 1.25 to 2.2 microns, taking into account NGC 7023, 2023, and 2068. All three nebulae were found to have similar near-infrared colors, despite widely different colors of their illuminating stars. The brightness level shown by two of the nebulae at 2.2 microns was too high to be easily accounted for on the basis of reflected light. Attention is given to a wide variety of possible emission mechanisms.

THE INFRARED SPECTRUM OF PROTONATED OVALENE IN SOLID PARA-HYDROGEN AND ITS POSSIBLE CONTRIBUTION TO INTERSTELLAR UNIDENTIFIED INFRARED EMISSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsuge, Masashi; Bahou, Mohammed; Lee, Yuan-Pern

The mid-infrared emission from galactic objects, including reflection nebulae, planetary nebulae, proto-planetary nebulae, molecular clouds, etc, as well as external galaxies, is dominated by the unidentified infrared (UIR) emission bands. Large protonated polycyclic aromatic hydrocarbons (H{sup +}PAHs) were proposed as possible carriers, but no spectrum of an H{sup +}PAH has been shown to exactly match the UIR bands. Here, we report the IR spectrum of protonated ovalene (7-C{sub 32}H{sub 15} {sup +}) measured in a para -hydrogen ( p -H{sub 2}) matrix at 3.2 K, generated by bombarding a mixture of ovalene and p -H{sub 2} with electrons during matrixmore » deposition. Spectral assignments were made based on the expected chemistry and on the spectra simulated with the wavenumbers and infrared intensities predicted with the B3PW91/6-311++G(2d,2p) method. The close resemblance of the observed spectral pattern to that of the UIR bands suggests that protonated ovalene may contribute to the UIR emission, particularly from objects that emit Class A spectra, such as the IRIS reflection nebula, NGC 7023.« less

Liquid scintillators with near infrared emission based on organoboron conjugated polymers.

PubMed

Tanaka, Kazuo; Yanagida, Takayuki; Yamane, Honami; Hirose, Amane; Yoshii, Ryousuke; Chujo, Yoshiki

2015-11-15

The organic liquid scintillators based on the emissive polymers are reported. A series of conjugated polymers containing organoboron complexes which show the luminescence in the near infrared (NIR) region were synthesized. The polymers showed good solubility in common organic solvents. From the comparison of the luminescent properties of the synthesized polymers between optical and radiation excitation, similar emission bands were detected. In addition, less significant degradation was observed. These data propose that the organoboron conjugated polymers are attractive platforms to work as an organic liquid scintillator with the emission in the NIR region. Copyright © 2015 Elsevier Ltd. All rights reserved.

Emission Lines in the Near-infrared Spectra of the Infrared Quintuplet Stars in the Galactic Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Najarro, F.; Geballe, T. R.; Figer, D. F.

We report the detection of a number of emission lines in the 1.0–2.4 μ m spectra of four of the five bright-infrared dust-embedded stars at the center of the Galactic center’s (GC) Quintuplet Cluster. Spectroscopy of the central stars of these objects is hampered not only by the large interstellar extinction that obscures all of the objects in the GC, but also by the large amounts of warm circumstellar dust surrounding each of the five stars. The pinwheel morphologies of the dust observed previously around two of them are indicative of Wolf–Rayet colliding wind binaries; however, infrared spectra of eachmore » of the five have until now revealed only dust continua steeply rising to long wavelengths and absorption lines and bands from interstellar gas and dust. The emission lines detected, from ionized carbon and from helium, are broad and confirm that the objects are dusty late-type carbon Wolf–Rayet stars.« less

The Far-Infrared Emission of Radio Loud and Radio Quiet Quasars

NASA Technical Reports Server (NTRS)

Polletta, M.; Courvoisier, T. J.-L.; Wilkes, B. J.; Hooper, E. J.

2000-01-01

Continuum observations at radio, millimeter, infrared and soft X-ray energies are presented for a sample of 22 quasars, consisting of flat and steep spectrum radio loud, radio intermediate and radio quiet objects. The primary observational distinctions, among the different kinds of quasars in the radio and IR energy domains are studied using large observational datasets provided by ISOPHOT on board the Infrared Space Observatory, by the IRAM interferometer, by the sub-millimetre array SCUBA on JCMT, and by the European Southern Observatory (ESO) facilities IRAC1 on the 2.2 m telescope and SEST. The spectral energy distributions of all quasars from radio to IR energies are analyzed and modeled with non-thermal and thermal spectral components. The dominant mechanism emitting in the far/mid-IR is thermal dust emission in all quasars, with the exception of flat spectrum radio loud quasars for which the presence of thermal IR emission remains rather uncertain, since it is difficult to separate it from the bright non-thermal component. The dust is predominantly heated by the optical/ultraviolet radiation emitted from the external components of the AGN. A starburst contributes to the IR emission at different levels, but always less than the AGN (<= 27%). The distribution of temperatures, sizes, masses, and luminosities of the emitting dust are independent of the quasar type.

A SPITZER SURVEY OF MID-INFRARED MOLECULAR EMISSION FROM PROTOPLANETARY DISKS. I. DETECTION RATES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pontoppidan, Klaus M.; Blake, Geoffrey A.; Meijerink, Rowin

2010-09-01

We present a Spitzer InfraRed Spectrometer search for 10-36 {mu}m molecular emission from a large sample of protoplanetary disks, including lines from H{sub 2}O, OH, C{sub 2}H{sub 2}, HCN, and CO{sub 2}. This paper describes the sample and data processing and derives the detection rate of mid-infrared molecular emission as a function of stellar mass. The sample covers a range of spectral type from early M to A, and is supplemented by archival spectra of disks around A and B stars. It is drawn from a variety of nearby star-forming regions, including Ophiuchus, Lupus, and Chamaeleon. Spectra showing strong emissionmore » lines are used to identify which lines are the best tracers of various physical and chemical conditions within the disks. In total, we identify 22 T Tauri stars with strong mid-infrared H{sub 2}O emission. Integrated water line luminosities, where water vapor is detected, range from 5 x 10{sup -4} to 9 x 10{sup -3} L{sub sun}, likely making water the dominant line coolant of inner disk surfaces in classical T Tauri stars. None of the five transitional disks in the sample show detectable gaseous molecular emission with Spitzer upper limits at the 1% level in terms of line-to-continuum ratios (apart from H{sub 2}), but the sample is too small to conclude whether this is a general property of transitional disks. We find a strong dependence on detection rate with spectral type; no disks around our sample of 25 A and B stars were found to exhibit water emission, down to 1%-2% line-to-continuum ratios, in the mid-infrared, while more than half of disks around late-type stars (M-G) show sufficiently intense water emission to be detected by Spitzer, with a detection rate approaching 2/3 for disks around K stars. Some Herbig Ae/Be stars show tentative H{sub 2}O/OH emission features beyond 20 {mu}m at the 1%-2% level, however, and one of them shows CO{sub 2} in emission. We argue that the observed differences between T Tauri disks and Herbig Ae/Be disks are

MIRIS observation of near-infrared diffuse Galactic light

NASA Astrophysics Data System (ADS)

Onishi, Yosuke; Sano, Kei; Matsuura, Shuji; Jeong, Woong-Seob; Pyo, Jeonghyun; Kim, Il-Jong; Seo, Hyun Jong; Han, Wonyong; Lee, DaeHee; Moon, Bongkon; Park, Wonkee; Park, Younsik; Kim, MinGyu; Matsumoto, Toshio; Matsuhara, Hideo; Nakagawa, Takao; Tsumura, Kohji; Shirahata, Mai; Arai, Toshiaki; Ienaka, Nobuyuki

2018-06-01

We report near-infrared (IR) observations of high Galactic latitude clouds to investigate diffuse Galactic light (DGL), which is starlight scattered by interstellar dust grains. The observations were performed at 1.1 and 1.6 μm with a wide-field camera instrument, the Multi-purpose Infra-Red Imaging System (MIRIS) onboard the Korean satellite STSAT-3. The DGL brightness is measured by correlating the near-IR images with a far-IR 100 μm map of interstellar dust thermal emission. The wide-field observation of DGL provides the most accurate DGL measurement achieved to-date. We also find a linear correlation between optical and near-IR DGL in the MBM32 field. To study interstellar dust properties in MBM32, we adopt recent dust models with and without μm-sized very large grains and predict the DGL spectra, taking into account the reddening effect of the interstellar radiation field. The result shows that the observed color of the near-IR DGL is closer to the model spectra without very large grains. This may imply that dust growth in the observed MBM32 field is not active owing to the low density of its interstellar medium.

Hybrid metasurfaces for microwave reflection and infrared emission reduction.

PubMed

Pang, Yongqiang; Li, Yongfeng; Yan, Mingbao; Liu, Dongqing; Wang, Jiafu; Xu, Zhuo; Qu, Shaobo

2018-04-30

Controlling of electromagnetic wave radiation is of great importance in many fields. In this work, a hybrid metasurface (HMS) is designed to simultaneously reduce the microwave reflection and the infrared emission. The HMS is composed of the metal/dielectric/metal/dielectric/metal configuration. The reflection reduction at microwave frequencies mainly results from the phase cancellation technique, while the infrared emission reduction is due to the reflection of the metal with a high filling ration in the top layer. It has been analytically indicated that reflection reduction with an efficiency larger than 10 dB can be achieved in the frequency band of 8.2-18 GHz, and this has been well verified by the simulated and experimental results. Meanwhile, the designed HMS displays a low emission performance in the infrared band, with the emissivity less than 0.27 from 3 to 14 μm. It is believed that our proposal may find the application of multispectral stealth technology.

Near-infrared line and continuum emission from the blue dwarf galaxy II Zw 40

NASA Technical Reports Server (NTRS)

Joy, Marshall; Lester, Daniel F.

1988-01-01

A multicolor analysis of new near-infrared line and continuum measurements indicates that nebular recombination emission and photospheric radiation from young blue stars produce most of the near-infrared continuum emission in the central 6 arcsec of the dwarf galaxy II Zw 40. The derived nebular recombination level is in excellent agreement with independent observations of the radio free-free continuum. It is found that evolved stars, which dominate the near-infrared emission from normal galaxies, contribute no more than 25 percent of the total 2.2 micron flux in the central region of II Zw 40. It is concluded that the total mass of the evolved stellar population in the central 400 pc of the galaxy is less than about two hundred million solar. The total mass of recently formed stars is about two million solar, and the stellar mass ratio is exceptionally large. Thus, II Zw 40 is a quintessential starburst galaxy.

Directional infrared temperature and emissivity of vegetation: Measurements and models

NASA Technical Reports Server (NTRS)

Norman, J. M.; Castello, S.; Balick, L. K.

1994-01-01

Directional thermal radiance from vegetation depends on many factors, including the architecture of the plant canopy, thermal irradiance, emissivity of the foliage and soil, view angle, slope, and the kinetic temperature distribution within the vegetation-soil system. A one dimensional model, which includes the influence of topography, indicates that thermal emissivity of vegetation canopies may remain constant with view angle, or emissivity may increase or decrease as view angle from nadir increases. Typically, variations of emissivity with view angle are less than 0.01. As view angle increases away from nadir, directional infrared canopy temperature usually decreases but may remain nearly constant or even increase. Variations in directional temperature with view angle may be 5C or more. Model predictions of directional emissivity are compared with field measurements in corn canopies and over a bare soil using a method that requires two infrared thermometers, one sensitive to the 8 to 14 micrometer wavelength band and a second to the 14 to 22 micrometer band. After correction for CO2 absorption by the atmosphere, a directional canopy emissivity can be obtained as a function of view angle in the 8 to 14 micrometer band to an accuracy of about 0.005. Modeled and measured canopy emissivities for corn varied slightly with view angle (0.990 at nadir and 0.982 at 75 deg view zenith angle) and did not appear to vary significantly with view angle for the bare soil. Canopy emissivity is generally nearer to unity than leaf emissivity may vary by 0.02 with wavelength even though leaf emissivity. High spectral resolution, canopy thermal emissivity may vary by 0.02 with wavelength even though leaf emissivity may vary by 0.07. The one dimensional model provides reasonably accurate predictions of infrared temperature and can be used to study the dependence of infrared temperature on various plant, soil, and environmental factors.

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.

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.

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.

Determining the Leaf Emissivity of Three Crops by Infrared Thermometry

PubMed Central

Chen, Chiachung

2015-01-01

Plant temperature can provide important physiological information for crop management. Non-contact measurement with an infrared thermometer is useful for detecting leaf temperatures. In this study, a novel technique was developed to measure leaf emissivity using an infrared thermometer with an infrared sensor and a thermocouple wire. The measured values were transformed into true temperatures by calibration equations to improve the measurement accuracy. The relationship between two kinds of measurement temperatures and setting emissivities was derived as a model for calculating of true emissivity. The emissivities of leaves of three crops were calculated by the mathematical equation developed in this study. The mean emissivities were 0.9809, 0.9783, 0.981 and 0.9848 for Phalaenopsis mature and new leaves and Paphiopedilum and Malabar chestnut leaves, respectively. Emissivity differed significantly between leaves of Malabar chestnut and the two orchids. The range of emissivities determined in this study was similar to that in the literature. The precision of the measurement is acceptable. The method developed in this study is a real-time, in situ technique and could be used for agricultural and forestry plants. PMID:25988870

Long-wave, infrared laser-induced breakdown (LIBS) spectroscopy emissions from energetic materials.

PubMed

Yang, Clayton S-C; Brown, Ei E; Hommerich, Uwe; Jin, Feng; Trivedi, Sudhir B; Samuels, Alan C; Snyder, A Peter

2012-12-01

Laser-induced breakdown spectroscopy (LIBS) has shown great promise for applications in chemical, biological, and explosives sensing and has significant potential for real-time standoff detection and analysis. In this study, LIBS emissions were obtained in the mid-infrared (MIR) and long-wave infrared (LWIR) spectral regions for potential applications in explosive material sensing. The IR spectroscopy region revealed vibrational and rotational signatures of functional groups in molecules and fragments thereof. The silicon-based detector for conventional ultraviolet-visible LIBS operations was replaced with a mercury-cadmium-telluride detector for MIR-LWIR spectral detection. The IR spectral signature region between 4 and 12 μm was mined for the appearance of MIR and LWIR-LIBS emissions directly indicative of oxygenated breakdown products as well as dissociated, and/or recombined sample molecular fragments. Distinct LWIR-LIBS emission signatures from dissociated-recombination sample molecular fragments between 4 and 12 μm are observed for the first time.

A study of the large-scale infrared emission from a selected dark cloud

NASA Technical Reports Server (NTRS)

Young, Erick T.

1993-01-01

An investigation of the infrared emission energetics and embedded population in the rho Ophiuchi dark cloud is summarized. With a distance of approximately 140 pc, the rho Ophiuchi cloud is one of the closest regions of recent star formation. It is also one of the best studied such regions with numerous observations at all wavelengths. The Infrared Astronomy Satellite (IRAS) data of the cloud provided a new glimpse of the overall structure of the cloud. In particular, the interaction of radiation from the Sco-Oph OB Association on the external heating of the cloud was very evident on Skyflux and Survey CO-Add images produced by IRAS. The infrared survey also revealed a number of new embedded sources in the cloud which have subsequently been observed from the ground. In earlier study, the overall energies of the cloud using the IRAS data was explored. The main conclusions of that work were: (1) the overall luminosity of the cloud is well explained by the emission of the known B-stars, HD 147889, SR-3, and S1, along with a 15 percent contribution from the external radiation field; (2) the dust physical temperatures were significantly lower than the observed CO gas temperatures; and (3) dust grains are heated to only 10 percent to 20 percent of the total depth into the cloud. This analysis was extended by drawing on data from large-scale CO maps of Loren (1989) and from near-infrared surveys of the embedded population.

ALMA Multiple-transition Molecular Line Observations of the Ultraluminous Infrared Galaxy IRAS 20551-4250: Different HCN, HCO+, and HNC Excitation, and Implications for Infrared Radiative Pumping

NASA Astrophysics Data System (ADS)

Imanishi, Masatoshi; Nakanishi, Kouichiro; Izumi, Takuma

2017-11-01

We present our ALMA multi-transition molecular line observational results for the ultraluminous infrared galaxy IRAS 20551-4250, which is known to contain a luminous buried active galactic nucleus and shows detectable vibrationally excited (v 2 = 1f) HCN and HNC emission lines. The rotational J = 1-0, 4-3, and 8-7 of HCN, {{HCO}}+, and HNC emission lines were clearly detected at a vibrational ground level (v = 0). Vibrationally excited (v 2 = 1f) J = 4-3 emission lines were detected for HCN and HNC, but not for {{HCO}}+. Their observed flux ratios further support our previously obtained suggestion, based on J = 3-2 data, that (1) infrared radiative pumping plays a role in rotational excitation at v = 0, at least for HCN and HNC, and (2) HCN abundance is higher than {{HCO}}+ and HNC. The flux measurements of the isotopologue H13CN, {{{H}}}13{{CO}}+, and HN13C J = 3-2 emission lines support the higher HCN abundance scenario. Based on modeling with collisional excitation, we constrain the physical properties of these line-emitting molecular gases, but find that higher HNC rotational excitation than HCN and {{HCO}}+ is difficult to explain, due to the higher effective critical density of HNC. We consider the effects of infrared radiative pumping using the available 5-30 μm infrared spectrum and find that our observational results are well-explained if the radiation source is located at 30-100 pc from the molecular gas. The simultaneously covered very bright CO J = 3-2 emission line displays a broad emission wing, which we interpret as being due to molecular outflow activity with the estimated rate of ˜ 150 {M}⊙ {{yr}}-1.

Polycyclic aromatic hydrocarbons and the unidentified infrared emission bands - Auto exhaust along the Milky Way

NASA Technical Reports Server (NTRS)

Allamandola, L. J.; Tielens, A. G. G. M.; Barker, J. R.

1985-01-01

The unidentified infrared emission features (UIR bands) are attributed to a collection of partially hydrogenated, positively charged polycyclic aromatic hydrocarbons (PAHs). This assignment is based on a spectroscopic analysis of the UIR bands. Comparison of the observed interstellar 6.2 and 7.7-micron bands with the laboratory measured Raman spectrum of a collection of carbon-based particulates (auto exhaust) shows a very good agreement, supporting this identification. The infrared emission is due to relaxation from highly vibrationally and electronically excited states. The excitation is probably caused by UV photon absorption. The infrared fluorescence of one particular, highly vibrationally excited PAH (chrysene) is modeled. In this analysis the species is treated as a molecule rather than bulk material and the non-thermodynamic equilibrium nature of the emission is fully taken into account. From a comparison of the observed ratio of the 3.3 to 11.3-micron UIR bands with the model calculations, the average number of carbon atoms per molecule is estimated to be about 20. The abundance of interstellar PAHs is calculated to be about 2 x 10 to the -7th with respect to hydrogen.

Host sensitized near-infrared emission in Nd3+ doped different alkaline-sodium-phosphate phosphors

NASA Astrophysics Data System (ADS)

Balakrishna, A.; Swart, H. C.; Kroon, R. E.; Ntwaeaborwa, O. M.

2018-04-01

Near-infrared (NIR) emitting phosphors of different alkaline based sodium-phosphate (MNa[PO4], where M = Mg, Ca, Sr and Ba were prepared by a conventional solution combustion method with fixed doping concentration of Nd3+ (1.0 mol%). The phosphors were characterized by powder X-ray diffraction, field emission scanning electron microscope, Fourier transform infrared spectroscopy, UV-vis spectroscopy and fluorescent spectrophotometry. The optical properties including reflectance, excitation and emission were investigated. The excitation spectra of the phosphors were characterized by a broadband extending from 450 to 900 nm. Upon excitation with a wavelength of 580 nm, the phosphor emits intensely infrared region at 872 nm, 1060 nm and 1325 nm which correspond to the 4F3/2 → 4I9/2, 4F3/2 → 4I11/2 and 4F3/2 → 4I13/2 transitions of Nd3+ ions and were found to vary for the different hosts. The strongest emission wavelength reaches 1060 nm. The most intense emission of Nd3+ was observed from Ca2+ incorporated host. The down conversion emissions of the material fall in the NIR region suggesting that the prepared phosphors have potential application in the development of photonic devices emitting in the NIR.

Harvesting renewable energy from Earth's mid-infrared emissions.

PubMed

Byrnes, Steven J; Blanchard, Romain; Capasso, Federico

2014-03-18

It is possible to harvest energy from Earth's thermal infrared emission into outer space. We calculate the thermodynamic limit for the amount of power available, and as a case study, we plot how this limit varies daily and seasonally in a location in Oklahoma. We discuss two possible ways to make such an emissive energy harvester (EEH): A thermal EEH (analogous to solar thermal power generation) and an optoelectronic EEH (analogous to photovoltaic power generation). For the latter, we propose using an infrared-frequency rectifying antenna, and we discuss its operating principles, efficiency limits, system design considerations, and possible technological implementations.

Theoretical studies of the infrared emission from circumstellar dust shells: the infrared characteristics of circumstellar silicates and the mass-loss rate of oxygen-rich late-type giants

NASA Technical Reports Server (NTRS)

Schutte, W. A.; Tielens, A. G.; Allamandola, L. J. (Principal Investigator)

1989-01-01

We have modeled the infrared emission of spherically symmetric, circumstellar dust shells with the aim of deriving the infrared absorption properties of circumstellar silicate grains and the mass-loss rates of the central stars. As a basis for our numerical studies, a simple semianalytical formula has been derived that illustrates the essential characteristics of the infrared emission of such dust shells. A numerical radiative transfer program has been developed and applied to dust shells around oxygen-rich late-type giants. Free parameters in such models include the absorption properties and density distribution of the dust. An approximate, analytical expression is derived for the density distribution of circumstellar dust driven outward by radiation pressure from a central source. A large grid of models has been calculated to study the influence of the free parameters on the emergent spectrum. These results form the basis for a comparison with near-infrared observations. Observational studies have revealed a correlation between the near-infrared color temperature, Tc, and the strength of the 10 micrometers emission or absorption feature, A10. This relationship, which essentially measures the near-infrared optical depth in terms of the 10 micrometers optical depth, is discussed. Theoretical A10-Tc relations have been calculated and compared to the observations. The results show that this relation is a sensitive way to determine the ratio of the near-infrared to 10 micrometers absorption efficiency of circumstellar silicates. These results as well as previous studies show that the near-infrared absorption efficiency of circumstellar silicate grains is much higher than expected from terrestrial minerals. We suggest that this enhanced absorption is due to the presence of ferrous iron (Fe2+) color centers dissolved in the circumstellar silicates. By using the derived value for the ratio of the near-infrared to 10 micrometers absorption efficiency, the observed A10-Tc

Near Infrared Emission from Defects in Few-Layer Phosphorene

NASA Astrophysics Data System (ADS)

Aghaeimeibodi, Shahriar; Kim, Je-Hyung; Waks, Edo

Atomically thin films of black phosphorus have recently received significant attention as low dimensional optical materials with a direct exciton emission whose wavelength is tunable by controlling the number of layers. In addition to this excitonic emission, recent work has revealed emission from defect states and reported new methods to manipulate them. Monolayer phosphorene exhibits emission from localized defect states at wavelengths near 920 nm. Increasing the number of layers should shift defect emission to longer wavelengths, enabling the material to span a broader spectral range. But defect emission from few-layer phosphorene has not yet been reported. Here, we demonstrate a new class of near infrared defects in few layer phosphorene. Photoluminescence measurement shows a bright emission around 1240 nm with a sublinear growth of emission intensity with linear increase of excitation intensity, confirming the defect nature of this emission. From time-resolved lifetime measurements we determine an emission lifetime of 1.2 ns, in contrast to exciton and trion lifetimes from few layer phosphorene previously reported to be in the range of a few hundred picoseconds. This work highlights the potential of bright defects of phosphorene for near infrared optoelectronic applications.

Measurements of trace constituents from atmospheric infrared emission and absorption spectra, a feasibility study

NASA Technical Reports Server (NTRS)

Goldman, A.; Williams, W. J.; Murcray, D. G.

1974-01-01

The feasibility of detecting eight trace constituents (CH4, HCl, HF, HNO3, NH3, NO, NO2 and SO2) against the rest of the atmospheric background at various altitudes from infrared emission and absorption atmospheric spectra was studied. Line-by-line calculations and observational data were used to establish features that can be observed in the atmospheric spectrum due to each trace constituent. Model calculations were made for experimental conditions which approximately represent state of the art emission and absorption spectrometers.

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.

Infrared emission from desorbed NO2(*) and NO(*)

NASA Technical Reports Server (NTRS)

Kofsky, I. L.; Barrett, J. L.

1985-01-01

Infrared photons from the radiative cascade accompany both the gas phase NO2 continuum chemiluminescence (which originates from its 2B2 and 2B1 states) and the NO beta bands. When these upper electronic states are excited by recombination/desorption at surfaces of low Earth orbiting spacecraft, similar IR emission spectrums will be observed. The principal NO2 features (other than the long wavelength tail of its electronic transitions) are the nu sub 3 fundamental sequence near 6.2 microns and nu sub 1 + nu sub 3 intercombination bands near 3.6 microns; NO would emit the delta v=1 and delta v=2 systems above 5.3 and 2.7 microns. Because of the long radiative lifetimes of the upper vibrational states, the infrared radiances in projections parallel to the vehicle surface (which we estimate) are substantially less than those of the visible and ultraviolet glows.

THE SUBARCSECOND MID-INFRARED VIEW OF LOCAL ACTIVE GALACTIC NUCLEI. III. POLAR DUST EMISSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asmus, D.; Hönig, S. F.; Gandhi, P., E-mail: dasmus@eso.org

2016-05-10

Recent mid-infrared (MIR) interferometric observations have shown that in a few active galactic nuclei (AGNs) the bulk of the infrared emission originates from the polar region above the putative torus, where only a little dust should be present. Here, we investigate whether such strong polar dust emission is common in AGNs. Out of 149 Seyferts in the MIR atlas of local AGNs, 21 show extended MIR emission on single-dish images. In 18 objects, the extended MIR emission aligns with the position angle (PA) of the system axis, established by [O iii], radio, polarization, and maser-based PA measurements. The relative amountmore » of resolved MIR emission is at least 40% and scales with the [O iv] fluxes, implying a strong connection between the extended continuum and [O iv] emitters. These results together with the radio-quiet nature of the Seyferts support the scenario that the bulk of MIR emission is emitted by dust in the polar region and not by the torus, which would demand a new paradigm for the infrared emission structure in AGNs. The current low detection rate of polar dust in the AGNs of the MIR atlas is explained by the lack of sufficient high-quality MIR data and the requirements on the orientation, strength of narrow-line region, and distance of the AGNs. The James Webb Space Telescope will enable much deeper nuclear MIR studies with comparable angular resolution, allowing us to resolve the polar emission and surroundings in most of the nearby AGNs.« less

Infrared Emission and Thermal Processes in Spiral Galaxies

NASA Technical Reports Server (NTRS)

Mundy, Lee; Wolfire, Mark

1999-01-01

In this research we constructed theoretical models of the infrared and submillimeter line and continuum emission from the neutral interstellar medium in the Milky Way and external galaxies. The model line intensities were compared to observations of the Galactic disk and several galaxies to determine the average physical properties of the neutral gas including the density, temperature, and ultraviolet radiation field which illuminates the gas. In addition we investigated the heating mechanisms in the Galactic disk and estimated the emission rate of the [C 11] 158 micrometer line as a function of position in the Galaxy. We conclude that the neutral gas is heated mainly by the grain photoelectric effect and that a two phase (CNM+WNM) is possible between Galactic radii R = 3 kpc and R = 18 kpc. Listings of meeting presentations and publications are included.

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

Hot Dust! Late-Time Infrared Emission From Supernovae

NASA Astrophysics Data System (ADS)

Fox, Ori; Skrutskie, M. F.; Chevalier, R. A.

2010-01-01

Supernovae light curves typically peak and fade in the course of several months. Some supernovae , however, exhibit late-time infrared emission that in some cases can last for several years. These supernovae tend to be of the Type IIn subclass, which is defined by narrow hydrogen and helium emission lines arising from a dense, pre-existing circumstellar medium excited by the supernova radiation. Such a late-time ``IR excess'' with respect to the optical blackbody counterpart typically indicates the presence of warm dust. The origin and heating mechanism of the dust is not, however, always well constrained. In this talk, I will explore several scenarios that explain the observed late-time emission. In particular, I will discuss the case of the Type IIn SN 2005ip, which has displayed an ``IR excess'' for over 3 years. The results allow us to interpret the progenitor system and better understand the late stages of stellar evolution. Much of the data used for this analysis were obtained with TripleSpec, a medium-resolution near-infrared spectrograph located at Apache Point Observatory, NM, and FanCam, a JHK imager located at Fan Mountain Observatory, just outside of Charlottesville, VA. These two instruments were designed, fabricated, built, and commissioned by our instrumentation group at the University of Virginia. I will also spend some time discussing these instruments. I would like to thank the following for financial support of this work throughout my graduate career: NASA GSRP, NSF AAG-0607737, Spitzer PID 50256, Achievement Reward for College Scientists (ARCS), and the Virginia Space Grant Consortium.

Tropospheric Emission Spectrometer (TES) for the Earth Observing System (EOS) CHEM Satellite

NASA Technical Reports Server (NTRS)

Beer, R.; Glavich, T.; Rider, D.

2000-01-01

The Tropospheric Emission Spectrometer (TES) is an imaging infrared Fourier transform spectrometer scheduled to be launched into polar sun-synchronous orbit on the Earth Observing System (EOS) CHEM satellite in December 2002.

Near-infrared Thermal Emission Detections of a Number of Hot Jupiters and the Systematics of Ground-based Near-infrared Photometry

NASA Astrophysics Data System (ADS)

Croll, Bryce; Albert, Loic; Jayawardhana, Ray; Cushing, Michael; Moutou, Claire; Lafreniere, David; Johnson, John Asher; Bonomo, Aldo S.; Deleuil, Magali; Fortney, Jonathan

2015-03-01

We present detections of the near-infrared thermal emission of three hot Jupiters and one brown dwarf using the Wide-field Infrared Camera (WIRCam) on the Canada-France-Hawaii Telescope (CFHT). These include Ks-band secondary eclipse detections of the hot Jupiters WASP-3b and Qatar-1b and the brown dwarf KELT-1b. We also report Y-band, K CONT-band, and two new and one reanalyzed Ks-band detections of the thermal emission of the hot Jupiter WASP-12b. We present a new reduction pipeline for CFHT/WIRCam data, which is optimized for high precision photometry. We also describe novel techniques for constraining systematic errors in ground-based near-infrared photometry, so as to return reliable secondary eclipse depths and uncertainties. We discuss the noise properties of our ground-based photometry for wavelengths spanning the near-infrared (the YJHK bands), for faint and bright stars, and for the same object on several occasions. For the hot Jupiters WASP-3b and WASP-12b we demonstrate the repeatability of our eclipse depth measurements in the Ks band; we therefore place stringent limits on the systematics of ground-based, near-infrared photometry, and also rule out violent weather changes in the deep, high pressure atmospheres of these two hot Jupiters at the epochs of our observations. Based on observations obtained with WIRCam, a joint project of Canada-France-Hawaii Telescope (CFHT), Taiwan, Korea, Canada, France, at the CFHT, which is operated by the National Research Council (NRC) of Canada, the Institute National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

Physical Retrieval of Surface Emissivity Spectrum from Hyperspectral Infrared Radiances

NASA Technical Reports Server (NTRS)

Li, Jun; Weisz, Elisabeth; Zhou, Daniel K.

2007-01-01

Retrieval of temperature, moisture profiles and surface skin temperature from hyperspectral infrared (IR) radiances requires spectral information about the surface emissivity. Using constant or inaccurate surface emissivities typically results in large retrieval errors, particularly over semi-arid or arid areas where the variation in emissivity spectrum is large both spectrally and spatially. In this study, a physically based algorithm has been developed to retrieve a hyperspectral IR emissivity spectrum simultaneously with the temperature and moisture profiles, as well as the surface skin temperature. To make the solution stable and efficient, the hyperspectral emissivity spectrum is represented by eigenvectors, derived from the laboratory measured hyperspectral emissivity database, in the retrieval process. Experience with AIRS (Atmospheric InfraRed Sounder) radiances shows that a simultaneous retrieval of the emissivity spectrum and the sounding improves the surface skin temperature as well as temperature and moisture profiles, particularly in the near surface layer.

NEAR-INFRARED THERMAL EMISSION DETECTIONS OF A NUMBER OF HOT JUPITERS AND THE SYSTEMATICS OF GROUND-BASED NEAR-INFRARED PHOTOMETRY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Croll, Bryce; Albert, Loic; Lafreniere, David

We present detections of the near-infrared thermal emission of three hot Jupiters and one brown dwarf using the Wide-field Infrared Camera (WIRCam) on the Canada-France-Hawaii Telescope (CFHT). These include Ks-band secondary eclipse detections of the hot Jupiters WASP-3b and Qatar-1b and the brown dwarf KELT-1b. We also report Y-band, K {sub CONT}-band, and two new and one reanalyzed Ks-band detections of the thermal emission of the hot Jupiter WASP-12b. We present a new reduction pipeline for CFHT/WIRCam data, which is optimized for high precision photometry. We also describe novel techniques for constraining systematic errors in ground-based near-infrared photometry, so asmore » to return reliable secondary eclipse depths and uncertainties. We discuss the noise properties of our ground-based photometry for wavelengths spanning the near-infrared (the YJHK bands), for faint and bright stars, and for the same object on several occasions. For the hot Jupiters WASP-3b and WASP-12b we demonstrate the repeatability of our eclipse depth measurements in the Ks band; we therefore place stringent limits on the systematics of ground-based, near-infrared photometry, and also rule out violent weather changes in the deep, high pressure atmospheres of these two hot Jupiters at the epochs of our observations.« less

Infrared and near infrared emission spectra of TeH and TeD

NASA Astrophysics Data System (ADS)

Yu, Shanshan; Shayesteh, Alireza; Fu, Dejian; Bernath, Peter F.

2005-04-01

The vibration-rotation emission spectra for the X2Π ground state and the near infrared emission spectra of the X2Π 1/2- X2Π 3/2 system of the TeH and TeD free radicals have been measured at high resolution using a Fourier transform spectrometer. TeH and TeD were generated in a tube furnace with a DC discharge of a flowing mixture of argon, hydrogen (or deuterium), and tellurium vapor. In the infrared region, for the X2Π 3/2 spin component we observed the 1-0, 2-1, and 3-2 vibrational bands for most of the eight isotopologues of TeH and the 1-0 and 2-1 bands for three isotopologues of TeD. For the X2Π 1/2- X2Π 3/2 transition, we observed the 0-0 and 1-1 bands for TeH and the 0-0, 1-1, and 2-2 bands for TeD. Except for a few lines, the tellurium isotopic shift was not resolved for the X2Π 1/2- X2Π 3/2 transitions of TeH and TeD. Local perturbations with Δ v = 2 between the two spin components of the X2Π state of TeH were found: X2Π 1/2, v = 0 with X2Π 3/2, v = 2; X2Π 1/2, v = 1 with X2Π 3/2, v = 3. The new data were combined with the previous data from the literature and two kinds of fits (Hund's case (a) and Hund's case (c)) were carried out for each of the 10 observed isotopologues: 130TeD, 128TeD, 126TeD, 130TeH, 128TeH, 126TeH, 125TeH, 124TeH, 123TeH, and 122TeH.

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.

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.

Excitation Mechanisms of Near-Infrared Emission Lines in LINER Galaxies

NASA Astrophysics Data System (ADS)

Boehle, Anna

2017-01-01

I will present high spatial resolution, integral field spectroscopic observations of the nearby LINER (low ionization nuclear emission line region) galaxy NGC 404. LINERs are found at the centers of ~1/3 of galaxies within 40 Mpc, but their physical nature is not well understood. Although NGC 404 is thought to host a intermediate mass black hole at its center, it is unclear whether accretion onto the black hole or another mechanism such as shock excitation drives its LINER emission. We use the OSIRIS near-infrared integral field spectrograph at Keck Observatory behind laser guide star adaptive optics to map the strength and kinematics of [FeII], H2, and hydrogen recombination lines in the nucleus of NGC 404. These observations have a spatial pixel sampling of 0.5 pc and span the central 30 pc of the galaxy. We find that the ionized and molecular gas show differences in their morphology and kinematics on parsec scales. In particular, there are regions with line ratios of [FeII]/Pa-β that are much higher than previously seen in spatially integrated spectra, significantly restricting the possible excitation mechanisms of the near-infrared emission lines in this source. We are also applying these analysis techniques to 10 additional nearby LINERs, a part of a larger sample of 14 sources, to understand what drives the emission lines in these active galaxies. As a part of this program, I worked on the upgrade of the detector in the OSIRIS spectrograph, which has allowed observations for this survey obtained since January 2016 to be taken with increased instrument sensitivity of a factor of ~2 at J-band wavelengths (1.2 - 1.4 microns) and ~1.6 at H- and K-band wavelengths (1.5 - 2.4 microns). I will present results from the LINER survey, the OSIRIS detector upgrade, and also touch on related work using stellar orbits around the Milky Way supermassive black hole Sgr A* to constrain the mass and distance to our own Galactic Center.

Prompt Emission of GRB 121217A from Gamma-Rays to the Near-Infrared

NASA Technical Reports Server (NTRS)

Elliott, J.; Yu, H.-F.; Schmidl, S.; Greiner, J.; Gruber, D.; Oates, S.; Kobayashi, S.; Zhang, B.; Cummings, J. R.; Filgas, R.;

Far-infrared line emission from the galaxy. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Stacey, G. J.

1985-01-01

The diffuse 157.74 micron (CII) emission from the Galaxy was sampled at several galactic longitudes near the galactic plane including complete scan across the plane at (II) = 2.16 deg and (II) = 7.28 deg. The observed (CII) emission profiles follow closely the nearby (12)CO (J=1to0) emission profiles. The (CII) emission probably arises in neutral photodissociation regions near the edges of giant moleclar clouds (GMC's). These regions have densities of approximately 350 cm(-3) and temperatures of approximately 300 K, and amount to 4x10(8) solar mass of hydrogen in the inner Galaxy. The total 157.74 micron luminosity of the Galaxy is estimated to be 6x10(7) solar luminosity. Estimates were also made of the galactic emission in other far-infrared (FIR) cooling lines. The (CII) line was found to be the dominant FIR emission line from the galaxy and the primary coolant for the warm neutral gas near the galactic plane. Other cooling lines predicted to be prominent in the galactic spectrum are discussed. The 145.53 micron (OI) emission line from the Orion nebula was also measured.

Harvesting renewable energy from Earth’s mid-infrared emissions

PubMed Central

Byrnes, Steven J.; Blanchard, Romain; Capasso, Federico

2014-01-01

It is possible to harvest energy from Earth's thermal infrared emission into outer space. We calculate the thermodynamic limit for the amount of power available, and as a case study, we plot how this limit varies daily and seasonally in a location in Oklahoma. We discuss two possible ways to make such an emissive energy harvester (EEH): A thermal EEH (analogous to solar thermal power generation) and an optoelectronic EEH (analogous to photovoltaic power generation). For the latter, we propose using an infrared-frequency rectifying antenna, and we discuss its operating principles, efficiency limits, system design considerations, and possible technological implementations. PMID:24591604

Investigation of PTFE transfer films by infrared emission spectroscopy and phase-locked ellipsometry

NASA Technical Reports Server (NTRS)

Lauer, James L.; Bunting, Bruce G.; Jones, William R., Jr.

1987-01-01

When a PTFE sheet was rubbed unidirectionally over a smooth surface of stainless steel an essentially monomolecular transfer film was formed. By ellipsometric and emission infrared spectroscopic techniques it was shown that the film was 10 to 15 A thick and birefringent. From the intensity differences of infrared bands obtained with a polarizer passing radiation polarized in mutually perpendicular planes, it was possible to deduce transfer film orientation with the direction of rubbing. After standing in air for several weeks the transfer films apparently increased in thickness by as much as threefold. At the same time both the index of refraction and the absorption index decreased. Examination of the surfaces by optical and electron microscopies showed that the films had become porous and flaky. These observations were consistent with previous tribological measurements. The coefficients of friction decreased with the formation of the transfer film but increased again as the film developed breaks. The applicability of the ellipsometric and polarized infrared emission techniques to the identification of monomolecular tribological transfer films of polymers such as PTFE has been demonstrated.

Extended mid-infrared emission from VV 114: Probing the birth of a ULIRG

NASA Astrophysics Data System (ADS)

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

2002-08-01

We present our 5-16 mu m spectro-imaging observations of VV 114, an infrared luminous early-stage merger of two galaxies VV 114E and VV 114W, taken with the ISOCAM camera on-board the Infrared Space Observatory. We find that only 40% of the mid-infrared (MIR) flux is associated with a compact nuclear region of VV 114E, while the rest of the emission originates from a rather diffuse component extended over several kpc in the regions between VV 114E and VV 114W. This is in stark contrast with the very compact MIR starbursts usually seen in luminous and ultraluminous infrared galaxies. A secondary peak of MIR emission is associated with an extra-nuclear star forming region of VV 114W which displays the largest Hα equivalent width in the whole system. Comparing our data with the distribution of the molecular gas and cold dust, as well as with radio observations, it becomes evident that the conversion of molecular gas into stars can be triggered over large areas at the very first stages of an interaction. This extended star formation along with the extreme nuclear starburst observed in VV 114E can easily lead to the heating of dust grains found in the tidally disturbed disks of the progenitor galaxies and subsequently traced via their MIR emission. The presence of a very strong continuum at the 5-6.5 mu m range in the spectrum of VV 114E indicates that an enshrouded active galactic nucleus (AGN) may contribute to ~ 40% of its MIR flux. We finally note that the relative variations in the UV to radio spectral properties between VV 114E and VV 114W provide evidence that the extinction-corrected star formation rate of similar objects at high z, such as those detected in optical deep surveys, cannot be accurately derived from their rest-frame UV properties. 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

Modelling Middle Infrared Thermal Imagery from Observed or Simulated Active Fire

NASA Astrophysics Data System (ADS)

Paugam, R.; Gastellu-Etchegorry, J. P.; Mell, W.; Johnston, J.; Filippi, J. B.

2016-12-01

The Fire Radiative Power (FRP) is used in the atmospheric and fire communities to estimate fire emission. For example, the current version of the emission inventory GFAS is using FRP observation from the MODIS sensors to derive daily global distribution of fire emissions. Although the FRP product is widely accepted, most of its theoretical justifications are still based on small scale burns. When up-scaling to large fires effects of view angle, canopy cover, or smoke absorption are still unknown. To cover those questions, we are building a system based on the DART radiative transfer model to simulate the middle infrared radiance emitted by a propagating fire front and propagating in the surrounding scene made of ambient vegetation and plume aerosols. The current version of the system was applied to fire ranging from a 1m2 to 7ha. The 3D fire scene used as input in DART is made of the flame, the vegetation (burnt and unburnt), and the plume. It can be either set up from [i] 3D physical based model scene (ie WFDS, mainly applicable for small scale burn), [ii] coupled 2D fire spread - atmospheric models outputs (eg ForeFire-MesoNH) or [iii] derived from thermal imageries observations (here plume effects are not considered). In the last two cases, as the complexity of physical processes occurring in the flame (in particular soot formation and emission) is not to solved, the flames structures are parameterized with (a) temperature and soot concentration based on empirical derived profiles and (b) 3D triangular shape hull interpolated at the fire front location. Once the 3D fire scene is set up, DART is then used to render thermal imageries in the middle infrared. Using data collected from burns conducted at different scale, the modelled thermal imageries are compared against observations, and effects of view angle are discussed.

Enhanced infrared emissivity of CeO2 coatings by La doping

NASA Astrophysics Data System (ADS)

Huang, Jianping; Fan, Chenglei; Song, Guangping; Li, Yibin; He, Xiaodong; Zhang, Xinjiang; Sun, Yue; Du, Shanyi; Zhao, Yijie

2013-09-01

Pure CeO2 and La doped CeO2 (LDC) coatings were prepared on nickel-based substrates by electron beam physical vapor deposition at 1173 K. The infrared emissivity in 2.5-25 μm of LDC coatings was enhanced with the increase of La concentration at high temperature 873-1273 K. Compared to the undoped CeO2 coating, the infrared emissivity of 16.7% LDC coating increases by 55%, and reaches up to 0.9 at 873 K. The enhancement of doped coatings’ emissivity is attributed to the increasing lattice absorption and free-carrier absorption. The high emissivity LDC coatings show a promising potential in high temperature application.

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

NASA Technical Reports Server (NTRS)

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

1994-01-01

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

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.;

The enhanced and broadband near-infrared emission in Pr3+/Nd3+ co-doped tellurite glass

NASA Astrophysics Data System (ADS)

Zhou, Zizhong; Zhou, Yaxun; Cheng, Pan; Zhou, Minghan; Su, Xiue; Li, Jun

2017-11-01

This paper reports an enhanced and broadband near-infrared fluorescence emission in the Pr3+/Nd3+ co-doped tellurite glass, which was prepared using melt-quenching technique. Under the excitation of 488 nm laser diode (LD), three near-infrared emission bands at around 0.9, 1.04 and 1.30 μm from 3P1,0 → 1G4, 1G4→3H4 and 1G4→3H5 radiative transitions respectively were observed in the Pr3+ single-doped glass, and the fluorescence intensities increased further with the introduction of Nd3+ ions, which is mainly attributed to the energy transfers from Nd3+ to Pr3+ emissions. Meanwhile, the spectral overlapping of Pr3+:1G4→3H4 and Nd3+:4F3/2 → 4I11/2 radiative transitions resulted in a broadband emission ranging from 1000 to 1100 nm, whose full-width at half-maximum (FWHM) reached about 66 nm. Additionally, the spectroscopic properties of Nd3+ and Pr3+ ions were analyzed using Judd-Ofelt theory and the thermal stability property of prepared glass was characterized by the differential scanning calorimeter (DSC) measurement, and larger than 134 °C for the difference ΔT(=Tx -Tg) was observed, which indicates its feasibility for later fiber drawing. The enhanced fluorescence and broadband emission indicate that Pr3+/Nd3+ co-doped tellurite glass can be applied in the near-infrared band tunable lasers and broadband optical amplifiers.

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%.

The use of stereoscopic satellite observation in the determination of the emissivity of cirrus

NASA Astrophysics Data System (ADS)

Szejwach, G.; Sletten, T. N.; Hasler, A. F.

The feasibility of determining cirrus ``emissivity'' from combined stereoscopic and infrared satellite observations in conjunction with radiosounding data is investigated for a particular case study. Simultaneous visible images obtained during SESAME-1979 from two geosynchronous GOES meteorological satellites were processed on the NASA/Goddard interactive system (AOIPS) and were used to determine the stereo cloud top height ZC as described by Hasler [1]. Iso-contours of radiances were outlined on the corresponding infrared image. Total brightness temperature TB and ground surface brightness temperature TS were inferred from the radiances. The special SESAME network of radiosoundings was used to determine the cloud top temperature TCLD at the level defined by ZC. The ``effective cirrus emissivity'' NE where N is the fractional cirrus cloudiness and E is the emissivity in a GOES infrared picture element of about 10 km × 10 km is then computed from TB, TS and TCLD.

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

NASA Technical Reports Server (NTRS)

Spinoglio, Luigi; Smith, Howard A.; Gonzalez-Alfonso, Eduardo; Fisher, Jacqueline

2005-01-01

We report on the analysis of the first complete far-infrared spectrum (43-197 microns) of the Seyfert 2 galaxy NGC 1068 as observed with the Long Wavelength Spectrometer (LWS) onboard the Infrared Space Observatory (ISO). In addition to the 7 expected ionic fine structure emission lines, the OH rotational lines at 79, 119 and 163 microns were all detected in emission, which is unique among galaxies with full LWS spectra, where the 119 micron line, where detected, is always in absorption. The observed line intensities were modelled together with IS0 Short Wavelength Spectrometer (SWS) and optical and ultraviolet line intensities from the literature, considering two independent emission components: the AGN component and the starburst component in the circumnuclear ring of approximately 3kpc in size. Using the UV to mid-IR emission line spectrum to constrain the nuclear ionizing continuum, we have confirmed previous results: a canonical power-law ionizing spectrum is a poorer fit than one with a deep absorption trough, while the presence of a big blue bump is ruled out. Based on the instantaneous starburst age of 5 Myr constrained by the Br gamma equivalent width in the starburst ring, and starburst synthesis models of the mid- and far-infrared fine-structure line emission, a low ionization parameter (U=10(exp -3.5)) and low densities (n=100 cm (exp -3)) are derived. Combining the AGN and starburst components, we succeed in modeling the overall UV to far-IR atomic spectrum of SGC 1068, reproducing the line fluxes to within a factor 2.0 on average with a standard deviation of 1.4. The OH 119 micron emission indicates that the line is collisionally excited, and arises in a warm and dense region. The OH emission has been modeled using spherically symmetric, non-local, non-LTE radiative transfer models. The models indicate that the bulk of the emission arises from the nuclear region, although some extended contribution from the starburst is not ruled out. The OH abundance

Are TiC Grains a Carrier of the 21 Micron Emission Band Observed around Post-Asymptotic Giant Branch Objects?

NASA Astrophysics Data System (ADS)

Chigai, Takeshi; Yamamoto, Tetsuo; Kaito, Chihiro; Kimura, Yuki

2003-04-01

The carrier of the 21 μm band observed in post-asymptotic giant branch (post-AGB) stars is examined. We analyze the infrared spectra of the TiC clusters measured by von Helden et al. in 2000 and determine the absorption efficiency Q in the 21 μm band. Using Q, we estimate the Ti/Si abundance ratios needed to realize the flux ratios of the 21 and 11 μm emission observed in the infrared spectra of the post-AGB stars exhibiting both 21 and 11 μm emission. In view of the nature of the TiC condensation by which TiC grains are quickly mantled by graphite, we calculate the emission spectra of the graphite-coated TiC grains and other possible types of core-mantle grains and compare with the observed spectra. Both the abundance and condensation considerations strongly suggest that TiC is an implausible carrier of the observed infrared 21 μm feature around carbon-rich post-AGB stars.

Properties and Applications of High Emissivity Composite Films Based on Far-Infrared Ceramic Powder.

PubMed

Xiong, Yabo; Huang, Shaoyun; Wang, Wenqi; Liu, Xinghai; Li, Houbin

2017-11-29

Polymer matrix composite materials that can emit radiation in the far-infrared region of the spectrum are receiving increasing attention due to their ability to significantly influence biological processes. This study reports on the far-infrared emissivity property of composite films based on far-infrared ceramic powder. X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray powder diffractometry were used to evaluate the physical properties of the ceramic powder. The ceramic powder was found to be rich in aluminum oxide, titanium oxide, and silicon oxide, which demonstrate high far-infrared emissivity. In addition, the micromorphology, mechanical performance, dynamic mechanical properties, and far-infrared emissivity of the composite were analyzed to evaluate their suitability for strawberry storage. The mechanical properties of the far-infrared radiation ceramic (cFIR) composite films were not significantly influenced ( p ≥ 0.05) by the addition of the ceramic powder. However, the dynamic mechanical analysis (DMA) properties of the cFIR composite films, including a reduction in damping and shock absorption performance, were significant influenced by the addition of the ceramic powder. Moreover, the cFIR composite films showed high far-infrared emissivity, which has the capability of prolonging the storage life of strawberries. This research demonstrates that cFIR composite films are promising for future applications.

Spatially resolved mid-infrared observations of the triple system T Tauri

NASA Astrophysics Data System (ADS)

Ratzka, Th.; Schegerer, A. A.; Leinert, Ch.; Ábrahám, P.; Henning, Th.; Herbst, T. M.; Köhler, R.; Wolf, S.; Zinnecker, H.

2009-08-01

Aims: The aim of this study is to enhance our knowledge of the characteristics and distribution of the circumstellar dust associated with the individual components of the young hierarchical triple system T Tau. Methods: To reach this goal, observations in the N-band (8-13 μm) with the two-telescope interferometric instrument MIDI at the VLTI were performed. For the northern component of the T Tau system, projected baseline lengths of 43 m, 62 m, and 85 m were used. For the southern binary projected baseline lengths of equivalent resolution could be utilised. Our study is based on both the interferometric and the spectrophotometric measurements and is supplemented by new visual and infrared photometry. Also, the phases were investigated to determine the dominating mid-infrared source in the close southern binary. The data were fit with the help of a sophisticated physical disc model. This model utilises the radiative transfer code MC3D that is based on the Monte-Carlo method. Results: Extended mid-infrared emission is found around all three components of the system. Simultaneous fits to the photometric and interferometric data confirm the picture of an almost face-on circumstellar disc around T Tau N. Towards this star, the silicate band is seen in emission. This emission feature is used to model the dust content of the circumstellar disc. Clear signs of dust processing are found. Towards T Tau S, the silicate band is seen in absorption. This absorption is strongly pronounced towards the infrared companion T Tau Sa as can be seen from the first individual N-band spectra for the two southern components. Our fits support the previous suggestion that an almost edge-on disc is present around T Tau Sa. This disc is thus misaligned with respect to the circumstellar disc around T Tau N. The interferometric data indicate that the disc around T Tau Sa is oriented in the north-south direction, which favours this source as launching site for the east-western jet. We further

Characterization of Jupiter's Atmosphere from Observation of Thermal Emission by Juno and Ground-Based Supporting Observations

NASA Astrophysics Data System (ADS)

Orton, G. S.; Momary, T.; Tabataba-Vakili, F.; Janssen, M. A.; Hansen, C. J.; Bolton, S. J.; Li, C.; Adriani, A.; Mura, A.; Grassi, D.; Fletcher, L. N.; Brown, S. T.; Fujiyoshi, T.; Greathouse, T. K.; Kasaba, Y.; Sato, T. M.; Stephens, A.; Donnelly, P.; Eichstädt, G.; Rogers, J.

2017-12-01

Ground-breaking measurements of thermal emission at very long wavelengths have been made by the Juno mission's Microwave Radiometer (MWR). We examine the relationship between these and other thermal emission measurements by the Jupiter Infrared Auroral Mapper (JIRAM) at 5 µm and ground-based supporting observations in the thermal infrared that cover the 5-25 µm range. The relevant ground-based observations of thermal emission are constituted from imaging and scanning spectroscopy obtained at the NASA Infrared Telescope Facility (IRTF), the Gemini North Telescope, the Subaru Telescope and the Very Large Telescope. A comparison of these results clarifies the physical properties responsible for the observed emissions, i.e. variability of the temperature field, the cloud field or the distribution of gaseous ammonia. Cross-references to the visible cloud field from Juno's JunoCam experiment and Earth-based images are also useful. This work continues an initial comparison by Orton et al. (2017, GRL 44, doi: 10.1002/2017GL073019) between MWR and JIRAM results, together with ancillary 5-µm IRTF imaging and with JunoCam and ground-based visible imaging. These showed a general agreement between MWR and JIRAM results for the 5-bar NH3 abundance in specific regions of low cloud opacity but only a partial correlation between MWR and 5-µm radiances emerging from the 0.5-5 bar levels of the atmosphere in general. Similar to the latter, there appears to be an inconsistent correlation between MWR channels sensitive to 0.5-10 bars and shorter-wavelength radiances in the "tails" of 5-µm hot spots , which may be the result of the greater sensitivity of the latter to particulate opacity that could depend on the evolution history of the particular features sampled. Of great importance is the interpretation of MWR radiances in terms of the variability of temperature vs. NH3 abundances in the 0.5-5 bar pressure range. This is particularly important to understand MWR results in

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.

Tropospheric Emission Spectrometer for the Earth Observing System

NASA Technical Reports Server (NTRS)

Glavich, Thomas A.; Beer, Reinhard

1991-01-01

A Tropospheric Emission Spectrometer (TES) for the Earth Observing System (EOS) series of polar-orbiting platforms is described. TES is aimed at studying tropospheric chemistry, in particular, the exchange of gases between the surface and the atmosphere, urban and regional pollution, acid rain precursors, sources and sinks of greenhouse gases, and the interchange of gases between the troposphere and the stratosphere. TES is a high-resolution (0.025/cm) infrared Fourier transform spectrometer operating in the passive thermal-emission mode in a very wide spectral range (600 to 4350/cm; 2.3 to 16.7 microns). TES has 32 spatial pixels in each of four optically conjugated linear detector arrays, each optimized for a different spectral region.

Infrared camera assessment of skin surface temperature--effect of emissivity.

PubMed

Bernard, V; Staffa, E; Mornstein, V; Bourek, A

2013-11-01

Infrared thermoimaging is one of the options for object temperature analysis. Infrared thermoimaging is unique due to the non-contact principle of measurement. So it is often used in medicine and for scientific experimental measurements. The presented work aims to determine whether the measurement results could be influenced by topical treatment of the hand surface by various substances. The authors attempted to determine whether the emissivity can be neglected or not in situations of topical application of substances such as ultrasound gel, ointment, disinfection, etc. The results of experiments showed that the value of surface temperature is more or less distorted by the topically applied substance. Our findings demonstrate the effect of emissivity of applied substances on resulting temperature and showed the necessity to integrate the emissivity into calculation of the final surface temperature. Infrared thermoimaging can be an appropriate method for determining the temperature of organisms, if this is understood as the surface temperature, and the surrounding environment and its temperature is taken into account. Copyright © 2012 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Rocket-borne observation of singly ionized carbon 158 micron emission from the diffuse interstellar medium

NASA Astrophysics Data System (ADS)

Bock, James Joseph

1994-01-01

We report an observation of 158 micron line emission from singly ionized carbon from the diffuse interstellar medium at high galactic latitude. The integrated line intensity is measured in a 36 arcmin field-of-view along a triangular scan path in a 5 deg x 20 deg region in Ursa Major using a rocket-borne, liquid helium cooled spectrophotometer. The scan includes high latitude infrared cirrus, molecular clouds, a bright external galaxy, M82, and the HI Hole, which is a region of uniquely low neutral hydrogen column density. Emission from (CII) is observed in all regions and, in the absence of appreciable CO emission, is well correlated with neutral hydrogen column density. We observe a (CII) gas cooling rate which varies from (3.25 +/- 0.8 to 1.18 +/- 0.4) x 10-26 ergs-1 H-atom-1, in good agreement with recent observations of UV absorption lines at high galactic latitude. Regions with CO emission have enhanced (CII) line emission over that expected from the correlation with neutral hydrogen column density. The line-to-continuum ratio varies from I(CII)/lambda Ilambda = 0.002 to 0.008 in comparison with the all sky average of 0.0082 reported by FIRAS, which is heavily weighted towards the Galactic plane. The far-infrared continuum intensity, measured at 134 microns, 154 microns, and 186 microns, correlates with the 100 micron brightness measured by IRAS, and in regions excluding molecular clouds, with HI column density. The far-infrared brightness correlated with HI column density is fit by a thermal spectrum with a temperature T = 16.4 (+2.3/-1.8) K assuming an index of emissivity n = 2. The residual brightness after subtracting the emission correlated with neutral hydrogen column density yields an upper limit to the far-infrared extra-galactic background radiation of lambda Ilambda (154 microns) less than 2.6 x 10-12 W cm-2 sr-1. The observation of M82 confirms the laboratory calibration of the instrument. Unique instrumentation was developed to realize the

Properties and Applications of High Emissivity Composite Films Based on Far-Infrared Ceramic Powder

PubMed Central

Xiong, Yabo; Huang, Shaoyun; Wang, Wenqi; Liu, Xinghai; Li, Houbin

2017-01-01

Polymer matrix composite materials that can emit radiation in the far-infrared region of the spectrum are receiving increasing attention due to their ability to significantly influence biological processes. This study reports on the far-infrared emissivity property of composite films based on far-infrared ceramic powder. X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray powder diffractometry were used to evaluate the physical properties of the ceramic powder. The ceramic powder was found to be rich in aluminum oxide, titanium oxide, and silicon oxide, which demonstrate high far-infrared emissivity. In addition, the micromorphology, mechanical performance, dynamic mechanical properties, and far-infrared emissivity of the composite were analyzed to evaluate their suitability for strawberry storage. The mechanical properties of the far-infrared radiation ceramic (cFIR) composite films were not significantly influenced (p ≥ 0.05) by the addition of the ceramic powder. However, the dynamic mechanical analysis (DMA) properties of the cFIR composite films, including a reduction in damping and shock absorption performance, were significant influenced by the addition of the ceramic powder. Moreover, the cFIR composite films showed high far-infrared emissivity, which has the capability of prolonging the storage life of strawberries. This research demonstrates that cFIR composite films are promising for future applications. PMID:29186047

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.

Terrestrial FeO Continuum Emission Observed in Sky Spectra

NASA Astrophysics Data System (ADS)

Slanger, Tom G.; Melchiorri, R.; Saran, D. V.

2011-01-01

The terrestrial continuum emission in the visible spectral region has often been studied by both astronomers and aeronomers, in order to clarify backgrounds and the nature of the emissions. New observations from the ESI spectrograph on the Keck II telescope, as well as from the OSIRIS/Odin spectrograph and orbiter, have established that a major component of the emission originates with the FeO molecule [Evans et al., 2010]. This quasi-continuum peaks at 5950 A and extends from 5000 A well into the infrared. The identity has been demonstrated by comparison with meteor trains and laboratory measurements [Jenniskens et al., 2000]. Early studies of the continuum show consistency with the FeO emission as presently observed [Gadsden and Marovich, 1973]. Analysis of spectra from Kitt Peak [Neugent and Massey, 2010] demonstrates the great similarity between FeO emission in a clean atmosphere and high pressure sodium lamp emission in a polluted atmosphere. This research was supported by NSF Aeronomy under Grant ATM-0637433 . Evans, W.F.J., et al., Geophys. Res. Lett. [in press, 2010] Gadsden, M. and E. Marovich, J. Atm. Terr. Phys., 35, 1601-1614 [1973] Jenniskens, P., et al., Earth, Moon and Planets, 82-83, 429-434 [2000] Neugent, K.F. and P. Massey, PASP [in press, 2010

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.

Spectral characterization of surface emissivities in the thermal infrared

NASA Astrophysics Data System (ADS)

Niclòs, Raquel; Mira, Maria; Valor, Enric; Caselles, Diego; García-Santos, Vicente; Caselles, Vicente; Sánchez, Juan M.

2015-04-01

Thermal infrared (TIR) remote sensing trends to hyperspectral sensors on board satellites in the last decades, e.g., the current EOS-MODIS and EOS-ASTER and future missions like HyspIRI, ECOSTRESS, THIRSTY and MISTIGRI. This study aims to characterize spectrally the emissive properties of several surfaces, mostly soils. A spectrometer ranging from 2 to 16 μm, D&P Model 102, has been used to measure samples with singular spectral features, e.g. a sandy soil rich in gypsum sampled in White Sands (New Mexico, USA), salt samples, powdered quartz, and powdered calcite. These samples were chosen for their role in the assessment of thermal emissivity of soils, e.g., the calcite and quartz contents are key variables for modeling TIR emissivities of bare soils, along with soil moisture and organic matter. Additionally, the existence of large areas in the world with abundance of these materials, some of them used for calibration/validation activities of satellite sensors and products, makes the chosen samples interesting. White Sands is the world's largest gypsum dune field encompassing 400 km^2; the salt samples characterize the Salar of Uyuni (Bolivia), the largest salt flat in the world (up to 10,000 km^2), as well as the Jordanian and Israeli salt evaporation ponds at the south end of the Dead Sea, or the evaporation lagoons in Aigües-Mortes (France); and quartz is omnipresent in most of the arid regions of the world such as the Algodones Dunes or Kelso Dunes (California, USA), with areas around 700 km2 and 120 km^2, respectively. Measurements of target leaving radiance, hemispherical radiance reflected by a diffuse reflectance panel, and the radiance from a black body at different temperatures were taken to obtain thermal spectra with the D&P spectrometer. The good consistency observed between our measurements and laboratory spectra of similar samples (ASTER and MODIS spectral libraries) indicated the validity of the measurement protocol. Further, our study showed the

Models for infrared emission from IRAS galaxies

NASA Technical Reports Server (NTRS)

Rowan-Robinson, M.

1987-01-01

Models for the infrared emission from Infrared Astronomy Satellite (IRAS) galaxies by Rowan-Robinson and Crawford, by deJong and Brink, and by Helou, are reviewed. Rowan-Robinson and Crawford model the 12 to 100 micron radiation from IRAS galaxies in terms of 3 components: a normal disk component, due to interstellar cirrus; a starburst component, modeled as hot stars in an optically thick dust cloud; and a Seyfert component, modeled as a power-law continuum immersed in an n(r) variation r sup -1 dust cloud associated with the narrow-line region of the Seyfert nucleus. The correlations between the luminosities in the different components, the blue luminosity, and the X-ray luminosity of the galaxies are consistent with the model. Spectra from 0.1 to 1000 microns are predicted and compared with available observations. The de Jong and Brink, and Helou, model IRAS non-Seyfert galaxies in terms of a cool (cirrus) component and a warm (starburst) component. The de Jong and Brink estimate the face-on internal extinction in the galaxies and find that it is higher in galaxies with more luminous starbursts. In Helou's model the spectrum of the warm component varies strongly with the luminosity in that component. The three models are briefly compared.

Chandra ACIS Observations of Jovian X-Ray Emission

NASA Technical Reports Server (NTRS)

Garmire, Gordon; Elsner, Ronald; Feigelson, Eric; Ford, Peter; Gladstone, G. Randall; Hurley, Kevin; Metzger, Albert; Waite, J. Hunter, Jr.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

On November 25 and 26, 1999, the Chandra X-ray spacecraft conducted a set of four 19,000 sec observations of Jupiter. The ACIS-S instrument configuration was used for its good low energy efficiency and spatial resolution. An anomalous response was obtained which was subsequently attributed to strong jovian infrared radiation penetrating the detector and piling up spurious events across the entire X-ray range. However, the pre-observation establishment of an offsetting bias field has allowed the recovery of data from that portion of Jupiter's disc which remained within the elevated portion of the bias field during the observation. This ranges from fewer than 3000 sec to the entire observing time for about 10% of the planet. Auroral emission is seen near both poles in each observation. The northern aurora ia overall more intense than the southern, consistent with prior Einstein and ROSAT Observatory results. The southern aurora shows more modulation with Jupiter's rotation than the northern. Spatial resolution has been improved by at least a factor of two over prior measurements but convincing evidence of structure has not been seen. Lower latitude emission, first observed by ROSAT, is confirmed with flux levels averaging more than a factor of five below peak auroral values. Pronounced variation in the observed emission has occurred over the observing period. The spectral response extends from 0.24 keV, below which noise dominates, to about 1.2 keV. For all four observations the spectrum is clearly enhanced between 0.45 and 0.85 keV. This is apparently unequivocal evidence that Jupiter's X-ray emission is the result of oxygen and perhaps sulfur ions precipitating into the planet's atmosphere, where they undergo charge exchange interactions. The identification of specific transitions lines in the spectrum is among the ongoing efforts. A bremsstrahlung component has not yet been identified.

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.

Optically active polyurethane@indium tin oxide nanocomposite: Preparation, characterization and study of infrared emissivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yong; Zhou, Yuming, E-mail: ymzhou@seu.edu.cn; Ge, Jianhua

Highlights: ► Silane coupling agent of KH550 was used to connect the ITO and polyurethanes. ► Infrared emissivity values of the hybrids were compared and analyzed. ► Interfacial synergistic action and orderly secondary structure were the key factors. -- Abstract: Optically active polyurethane@indium tin oxide and racemic polyurethane@indium tin oxide nanocomposites (LPU@ITO and RPU@ITO) were prepared by grafting the organics onto the surfaces of modified ITO nanoparticles. LPU@ITO and RPU@ITO composites based on the chiral and racemic tyrosine were characterized by FT-IR, UV–vis spectroscopy, X-ray diffraction (XRD), SEM, TEM, and thermogravimetric analysis (TGA), and the infrared emissivity values (8–14 μm)more » were investigated in addition. The results indicated that the polyurethanes had been successfully grafted onto the surfaces of ITO without destroying the crystalline structure. Both composites possessed the lower infrared emissivity values than the bare ITO nanoparticles, which indicated that the interfacial interaction had great effect on the infrared emissivity. Furthermore, LPU@ITO based on the optically active polyurethane had the virtue of regular secondary structure and more interfacial synergistic actions between organics and inorganics, thus it exhibited lower infrared emissivity value than RPU@ITO based on the racemic polyurethane.« less

Infrared emission and tidal interactions of spiral galaxies

NASA Technical Reports Server (NTRS)

Byrd, Gene G.

1987-01-01

Computer simulations of tidal interactions of spiral galaxies are used to attempt to understand recent discoveries about infrared (IR) emitting galaxies. It is found that the stronger tidal perturbation by a companion the more disk gas clouds are thrown into nucleus crossing orbits and the greater the velocity jumps crossing spiral arms. Both these tidally created characteristics would create more IR emission by high speed cloud collisions and more IR via effects of recently formed stars. This expectation at greater tidal perturbation matches the observation of greater IR emission for spiral galaxies with closer and/or more massive companions. The greater collision velocities found at stronger perturbations on the models will also result in higher dust temperature in the colliding clouds. In the IR pairs examined, most have only one member, the larger, detected and when both are detected, the larger is always the more luminous. In simulations and in a simple analytic description of the strong distance dependence of the tidal force, it is found that the big galaxy of a pair is more strongly affected than the small.

Study of broadband near-infrared emission in Tm3+-Er3+ codoped TeO2-WO3-PbO glasses.

PubMed

Balda, R; Fernández, J; Fernández-Navarro, J M

2009-05-25

In this work, we report the near-infrared emission properties of Tm(3+)-Er(3+) codoped tellurite TeO(2)-WO(3)-PbO glasses under 794 nm excitation. A broad emission from 1350 to 1750 nm corresponding to the Tm(3+) and Er(3+) emissions is observed. The full width at half-maximum of this broadband increases with increasing [Tm]/[Er] concentration ratio up to a value of ~ 160 nm. The energy transfer between Tm(3+) and Er(3+) ions is evidenced by both the temporal behavior of the near-infrared luminescence and the effect of Tm3+ codoping on the visible upconversion of Er(3+) ions.

Design of a Far-Infrared Spectrometer for Atmospheric Thermal Emission Measurements

NASA Technical Reports Server (NTRS)

Johnson, David G.

2004-01-01

Global measurements of far infrared emission from the upper troposphere are required to test models of cloud radiative forcing, water vapor continuum emission, and cooling rates. Spectra with adequate resolution can also be used for retrieving atmospheric temperature and humidity profiles, and yet there are few spectrally resolved measurements of outgoing longwave flux at wavelengths longer than 16 m. It has been difficult to make measurements in the far infrared due to the need for liquid-helium cooled detectors and large optics to achieve adequate sensitivity and bandwidth. We review design considerations for infrared Fourier transform spectrometers, including the dependence of system performance on basic system parameters, and discuss the prospects for achieving useful sensitivity from a satellite platform with a lightweight spectrometer using uncooled detectors.

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

NASA Technical Reports Server (NTRS)

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

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

PubMed

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

1995-03-03

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

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

PubMed

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

2016-04-01

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

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

NASA Astrophysics Data System (ADS)

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

2017-02-01

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

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.

First Spitzer Space Telescope Observations of Magnetic Cataclysmic Variables: Evidence of Excess Emission at 3-8 μm

NASA Astrophysics Data System (ADS)

Howell, Steve B.; Brinkworth, Carolyn; Hoard, D. W.; Wachter, Stefanie; Harrison, Thomas; Chun, Howard; Thomas, Beth; Stefaniak, Linda; Ciardi, David R.; Szkody, Paula; van Belle, Gerard

2006-07-01

We present the first observations of magnetic cataclysmic variables using the Spitzer Space Telescope. We used the Infrared Array Camera to obtain photometry of the Polars EF Eri, GG Leo, V347 Pav, and RX J0154.0-5947 at 3.6, 4.5, 5.8, and 8.0 μm, respectively. In all of our targets, we detect excess mid-infrared emission over that expected from the component stars alone. We explore the origin of this IR excess by examining bremsstrahlung, cyclotron emission, circumbinary dust, and L/T brown dwarf secondary stars. Bremsstrahlung and cyclotron emission appear unlikely to be significant contributors to the observed fluxes. At present, the most likely candidate for the excess emission is dust that is probably located in a circumbinary disk with an inner temperature near 800 K. However, a simple dust disk plus any reasonable low-mass or brown dwarf-like secondary star is unable to fully explain the observed flux densities in the 3-8 μm region.

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

NASA Astrophysics Data System (ADS)

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

2015-08-01

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

A Thermal Infrared Emission Spectra Library for Unpowdered Meteorites

NASA Astrophysics Data System (ADS)

Ashley, J. W.; Christensen, P. R.

2007-12-01

Mid-infrared thermal emission spectra have been obtained for whole-rock (unpowdered) samples of the following 25 meteorites: Abee, Admire, Allende, Bondoc, Brahin, Bruderheim, Canyon Diablo, Carichic, Clover Springs, Dhofar 007, Estherville, Holbrook, Juancheng, Kapoeta, Long Island, Marion, Modoc, ALH77225, ALH77233, ALH84082, LEW85322, ALH85025, ALH79029, ALH77004, and LEW86015. Meteorites were provided through the Center for Meteorite Studies at ASU, Johnson Space Center and the NASA Antarctic Meteorite Working Group, and from private collections. The database was prepared to aid in the on-going detection and interpretation of meteorites on Mars using the Miniature Thermal Emission Spectrometer (Mini-TES) instruments on both Mars Exploration Rovers. It therefore includes several specimens of low, moderate, and high weathering intensities, reflecting different levels of water exposure in desert and non-desert environments. Unweathered falls are also considered. Samples represent all three chondrite classes, stony irons (mesosiderites and pallasites), and select achondrites. Special consideration is given to dust-covered iron-nickel meteorites as part of a separate study designed to evaluate the Mini-TES spectra of iron-nickel meteorites on Mars. All samples were analyzed at or near a temperature of 80° C using a modified Nicolet Nexus 670 FT-IR spectrometer at the Mars Space Flight Facility at Arizona State University. Data were collected within the 2000 to 200 wavenumber (5 to 50 microns) mid-infrared range. The results show that many meteorite types display moderate to wide variability in the depth and position of prominent absorption features, making them easily distinguishable from each other. Most previous meteorite spectroscopy studies have either focused on near-infrared reflectance spectra [e.g. 1], and/or involved powdered samples to represent asteroid regoliths in the mid-infrared [e.g. 2 & 3]. Particle size- related issues are often at the heart of

The First Reported Infrared Emission from the SN1006 Remnant

NASA Technical Reports Server (NTRS)

Winkler, P. Frank; Williams, Brian J.; Blair, William P.; Borkowski, Kazimierz J.; Ghavamian, Parviz; Long, Knox S.; Raymond, John C.; Reynolds, Stephen P.

2012-01-01

We report results of infrared imaging and spectroscopic observations of the SN 1006 remnant, carried out with the Spitzer Space Telescope. The 24 m image from MIPS clearly shows faint filamentary emission along the northwest rim of the remnant shell, nearly coincident with the Balmer filaments that delineate the present position of the expanding shock. The 24 m emission traces the Balmer filaments almost perfectly, but lies a few arcsec within, indicating an origin in interstellar dust heated by the shock. Subsequent decline in the IR behind the shock is presumably due largely to grain destruction through sputtering. The emission drops far more rapidly than current models predict, however, even for a higher proportion of small grains than would be found closer to the Galactic plane. The rapid drop may result in part from a grain density that has always been lowera relic effect from an earlier epoch when the shock was encountering a lower densitybut higher grain destruction rates still seem to be required. Spectra from three positions along the NW filament from the IRS instrument all show only a featureless continuum, consistent with thermal emission from warm dust. The dust-to-gas mass ratio in the pre-shock interstellar medium is lower than that expected for the Galactic ISM-as has also been observed in the analysis of IR emission from other SNRs but whose cause remains unclear. As with other SNIa remnants, SN1006 shows no evidence for dust grain formation in the supernova ejecta.

Infrared techniques for comet observations

NASA Technical Reports Server (NTRS)

Hanner, Martha S.; Tokunaga, Alan T.

1991-01-01

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

Modeling the unidentified infrared emission with combinations of polycyclic aromatic hydrocarbons

NASA Technical Reports Server (NTRS)

Allamandola, L. J.; Hudgins, D. M.; Sandford, S. A.

1999-01-01

The infrared emission band spectrum associated with many different interstellar objects can be modeled successfully by using combined laboratory spectra of neutral and positively charged polycyclic aromatic hydrocarbons (PAHs). These model spectra, shown here for the first time, alleviate the principal spectroscopic criticisms previously leveled at the PAH hypothesis and demonstrate that mixtures of free molecular PAHs can indeed account for the overall appearance of the widespread interstellar infrared emission spectrum. Furthermore, these models give us insight into the structures, stabilities, abundances, and ionization balance of the interstellar PAH population. These, in turn, reflect conditions in the emission zones and shed light on the microscopic processes involved in the carbon nucleation, growth, and evolution in circumstellar shells and the interstellar medium.

Hard X-Ray Emission of the Luminous Infrared Galaxy NGC 6240 as Observed by Nustar

NASA Technical Reports Server (NTRS)

Puccetti, S.; Comastri, A.; Bauer, F. E.; Brandt, W. N.; Fiore, F.; Harrison, F. A.; Luo, B.; Stern, D.; Urry, C. M.; Alexander, D. M.;

Infrared Photometry and Spectrophotometry of Supernova 1987A - Part Two - 1987NOV to 1991MAR Observations

NASA Astrophysics Data System (ADS)

Bouchet, P.; Danziger, I. J.

1993-06-01

We present the infrared (1-20 micron) observations of SN 1987A obtained at ESO La Silla between 29 October 1987 and 27 March 1991 (day 1493); photometry and narrow band CVF spectrophotometry (λ/{DELTA}λ ~ 60) were acquired during that period. The infrared light curves and the spectra are shown and discussed. The spectral energy distribution is dominated by an increasing IR excess after day 530 (beyond 3.5 microns) due to the presence of dust in the envelope which was first discovered by its spectroscopic signature. We show that dust is still present at least until day ~1400, and that the two zone model for the expanding envelope, suggested from the visible spectra obtained at ESO, can account for the observed changes in the near-infrared colours in the period days 530-560. Hydrogen lines, observed in the spectrum from the very beginning, are present until day 1109 (although Brγ is hardly noticeable on the 9 March 1990 spectrum) and we describe the variations of their intensities throughout our monitoring period. Attention is drawn to the presence of CO emission observed until November 1988, and to the evolution of cobalt through the observation of the fine structure line of [Co II] at 10.52 microns. The temporal behaviour of the emission lines due to [Ni I] 3.12 microns and [Si I] + [Fe II] 1.644 microns are also shown.

A model for the infrared emission from an OB star cluster environment

NASA Technical Reports Server (NTRS)

Leisawitz, D.

1991-01-01

A model for the infrared emission from the neighborhood of an OB star cluster is described. The distribution of gas and dust around the stars, properties of the dust, and the cluster and interstellar radiation fields are variable. The model can be applied to regions around clusters embedded to various degrees in their parental molecular clouds (i.e., compact H II regions, blister-type H II regions, and the tenuous H II regions ionized by naked O stars). The model is used to simulate IRAS observations of a typical blister H II region. Infrared surface brightness and spectral energy distributions are predicted and the impact of limited spatial resolution is illustrated. The model results are shown to be consistent with observations of the exemplary outer Galaxy OB cluster NGC 7380. It is planned to use the model as a diagnostic tool to probe the physical conditions and dust properties in star-formation regions and, ultimately, in an interpretation of the spectral energy distributions of spiral galaxies.

Atmosphere and climate studies of Mars using the Mars Observer pressure modulator infrared radiometer

NASA Technical Reports Server (NTRS)

Mccleese, D. J.; Haskins, R. D.; Schofield, J. T.; Zurek, R. W.; Leovy, C. B.; Paige, D. A.; Taylor, F. W.

1992-01-01

Studies of the climate and atmosphere of Mars are limited at present by a lack of meteorological data having systematic global coverage with good horizontal and vertical resolution. The Mars Observer spacecraft in a low, nearly circular, polar orbit will provide an excellent platform for acquiring the data needed to advance significantly our understanding of the Martian atmosphere and its remarkable variability. The Mars Observer pressure modulator infrared radiometer (PMIRR) is a nine-channel limb and nadir scanning atmospheric sounder which will observe the atmosphere of Mars globally from 0 to 80 km for a full Martian year. PMIRR employs narrow-band radiometric channels and two pressure modulation cells to measure atmospheric and surface emission in the thermal infrared. PMIRR infrared and visible measurements will be combined to determine the radiative balance of the polar regions, where a sizeable fraction of the global atmospheric mass annually condenses onto and sublimes from the surface. Derived meteorological fields, including diabatic heating and cooling and the vertical variation of horizontal winds, are computed from the globally mapped fields retrieved from PMIRR data.

The tropospheric emission spectrometer (TES) for the Earth Observing System (EOS)

NASA Technical Reports Server (NTRS)

Beer, R.

1992-01-01

In recent years, increasing concern has been expressed about Global Change - the natural and anthropogenic alteration of the Earth's environment involving global greenhouse warming and the associated climate change, urban and regional atmospheric pollution, acid deposition, regional increases in tropospheric zone, and the decrease in stratospheric ozone. A common theme among these problems is that they all involve those tropospheric trace gases which are fundamental to the biosphere-troposphere interaction, the chemistry of the free troposphere itself, and troposphere-stratosphere exchange. The chemical species involved all have spectral signatures within the near and mid infrared that can now be measured by advanced techniques of remote-sensing infrared spectroradiometry. Such a system is the Tropospheric Emission Spectrometer (TES), now in Phase B definition for the Earth Observing System (EOS) polar platforms. TES addresses these objectives by obtaining radiometrically calibrated, linewidth-limited spectral resolution, infrared spectra of the lower atmosphere using both natural thermal emission and reflected sunlight (where appropriate) in three different, but fully programmable, modes: a gobal mode, a pointed mode, and a limb-viewing mode. The goals of TES, its instrumentation, operational modes, sensitivity and data handling are discussed.

Fourier emission infrared microspectrophotometer for surface analysis. I - Application to lubrication problems

NASA Technical Reports Server (NTRS)

Lauer, J. L.; King, V. W.

1979-01-01

A far-infrared interferometer was converted into an emission microspectrophotometer for surface analysis. To cover the mid-infrared as well as the far-infrared the Mylar beamsplitter was made replaceable by a germanium-coated salt plate, and the Moire fringe counting system used to locate the moveable Michelson mirror was improved to read 0.5 micron of mirror displacement. Digital electronics and a dedicated minicomputer were installed for data collection and processing. The most critical element for the recording of weak emission spectra from small areas was, however, a reflecting microscope objective and phase-locked signal detection with simultaneous referencing to a blackbody source. An application of the technique to lubrication problems is shown.

Observations of Disks around Brown Dwarfs in the TW Hydra Association with the Spitzer Infrared Spectrograph

NASA Astrophysics Data System (ADS)

Morrow, A. L.; Luhman, K. L.; Espaillat, C.; D'Alessio, P.; Adame, L.; Calvet, N.; Forrest, W. J.; Sargent, B.; Hartmann, L.; Watson, D. M.; Bohac, C. J.

2008-04-01

Using SpeX at the NASA Infrared Telescope Facility and the Spitzer Infrared Spectrograph, we have obtained infrared spectra from 0.7 to 40 μm for three young brown dwarfs in the TW Hydra association (τ ~ 10 Myr), 2MASSW J1207334-393254, 2MASSW J1139511-315921, and SSSPM J1102-3431. The spectral energy distribution for 2MASSW J1139511-315921 is consistent with a stellar photosphere for the entire wavelength range of our data, whereas the other two objects exhibit significant excess emission at λ > 5μm. We are able to reproduce the excess emission from each brown dwarf using our models of irradiated accretion disks. According to our model fits, both disks have experienced a high degree of dust settling. We also find that silicate emission at 10 and 20 μm is absent from the spectra of these disks, indicating that grains in the upper disk layers have grown to sizes larger than ~5 μm. Both of these characteristics are consistent with previous observations of decreasing silicate emission with lower stellar masses and older ages. These trends suggest that either (1) the growth of dust grains, and perhaps planetesimal formation, occurs faster in disks around brown dwarfs than in disks around stars or (2) the radii of the mid-IR-emitting regions of disks are smaller for brown dwarfs than for stars, and grains grow faster at smaller disk radii. Finally, we note the possible detection of an unexplained emission feature near 14 μm in the spectra of both of the disk-bearing brown dwarfs. Based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory at the California Institute of Technology under NASA contract 1407.

Surface slope characteristics from Thermal Emission Spectrometer emission phase function observations

NASA Astrophysics Data System (ADS)

Edwards, C. S.; Bandfield, J. L.; Christensen, P. R.

2006-12-01

It is possible to obtain surface roughness characteristics, by measuring a single surface from multiple emission angles and azimuths in the thermal infrared. Surfaces will have different temperatures depending on their orientation relative to the sun. A different proportion of sunlit versus shaded surfaces will be in the field of view based on the viewing orientation, resulting in apparent temperature differences. This difference in temperature can be utilized to calculate the slope characteristics for the observed area. This technique can be useful for determining surface slope characteristics not resolvable by orbital imagery. There are two main components to this model, a surface DEM, in this case a synthetic, two dimensional sine wave surface, and a thermal model (provided by H. Kieffer). Using albedo, solar longitude, slope, azimuth, along with several other parameters, the temperature for each cell of the DEM is calculated using the thermal model. A temperature is then predicted using the same observation geometries as the Thermal Emission Spectrometer (TES) observations. A temperature difference is calculated for the two complementary viewing azimuths and emission angles from the DEM. These values are then compared to the observed temperature difference to determine the surface slope. This method has been applied to TES Emission Phase Function (EPF) observations for both the spectrometer and bolometer data, with a footprint size of 10s of kilometers. These specialized types of TES observations measure nearly the same surface from several angles. Accurate surface kinetic temperatures are obtained after the application of an atmospheric correction for the TES bolometer and/or spectrometer. Initial results include an application to the northern circumpolar dunes. An average maximum slope of ~33 degrees has been obtained, which makes physical sense since this is near the angle of repose for sand sized particles. There is some scatter in the data from separate

Research on optical reflectance and infrared emissivity of TiNx films depending on sputtering pressure

NASA Astrophysics Data System (ADS)

Lu, Linlin; Luo, Fa; Huang, Zhibin; Zhou, Wancheng; Zhu, Dongmei

2018-06-01

TiNx thin films were deposited on glass substrates using direct current reactive magnetron sputtering, and effects of sputtering pressure on optical reflectance and infrared emissivity of TiNx films were studied. The results indicated that sputtering pressure was a key factor to affect the optical reflectance and infrared emissivity of TiNx films in this study. When sputtering pressure varied from 0.3 Pa to 1.2 Pa, an average reflectance of less than 25% in the visible range was obtained for the prepared films. With the working pressure rise, the resistivity of TiNx films went up. Meanwhile, the infrared emissivity of the films increased. As sputtering pressure was 0.3 Pa, the infrared emissivity in the wavelength of 3-5 and 8-14 μm of TiNx film with dark color and low optical reflectance was less than 0.2.

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.

The link between IRAS spectra and near-infrared emission features in external galaxies

NASA Technical Reports Server (NTRS)

Desert, F. X.; Dennefeld, M.

1988-01-01

The relationship in external galaxies between the presence of the near-infrared (NIR) emission features attributed to polycyclic aromatic hydrocarbon (PAH) molecules, and the far-infrared (FIR) properties as observed by IRAS, is investigated. It is found that whenever the NIR features are absent in a galaxy, the FIR spectrum displays an enhancement at shorter wavelengths relative to normal galaxies. This enhancement is always associated with a strong activity in the galactic nucleus. Some Seyfert galaxies do not exhibit such an infrared signature and therefore they are probably energetically dominated by star-formation processes. Finally, the importance of hard UV photons and of the hot medium in the narrow line region of active nuclei is emphasized in relation to the survival of the PAH molecules. In this frame, the absence of PAHs in the galactic center could be taken as evidence for the presence of an active nucleus.

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

Infrared emission from tidal disruption events - probing the pc-scale dust content around galactic nuclei

NASA Astrophysics Data System (ADS)

Lu, Wenbin; Kumar, Pawan; Evans, Neal J.

2016-05-01

Recent UV-optical surveys have been successful in finding tidal disruption events (TDEs), in which a star is tidally disrupted by a supermassive black hole (BH). These TDEs release a huge amount of radiation energy Erad ˜ 1051-1052 erg into the circum-nuclear medium. If the medium is dusty, most of the radiation energy will be absorbed by dust grains within ˜1 pc from the BH and re-radiated in the infrared. We calculate the dust emission light curve from a 1D radiative transfer model, taking into account the time-dependent heating, cooling and sublimation of dust grains. We show that the dust emission peaks at 3-10 μm and has typical luminosities between 1042 and 1043 erg s-1 (with sky covering factor of dusty clouds ranging from 0.1 to 1). This is detectable by current generation of telescopes. In the near future, James Webb Space Telescope will be able to perform photometric and spectroscopic measurements, in which silicate or polycyclic aromatic hydrocarbon features may be found. Dust grains are non-spherical and may be aligned with the magnetic field, so the dust emission may be significantly polarized. Observations at rest-frame wavelength ≥ 2 μm have only been reported from two TDE candidates, SDSS J0952+2143 and SwiftJ1644+57. Although consistent with the dust emission from TDEs, the mid-infrared fluxes of the two events may be from other sources. Long-term monitoring is needed to draw a firm conclusion. We also point out two nearby TDE candidates (ASASSN-14ae and -14li) where the dust emission may be currently detectable. Detection of dust infrared emission from TDEs would provide information regarding the dust content and its distribution in the central pc of non-active galactic nuclei, which is hard to probe otherwise.

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.

Observations of emission in bright, low redshift quasars

NASA Technical Reports Server (NTRS)

1983-01-01

Ultraviolet, infrared, and optical spectra were combined to obtain a data set sample as broad as possible in the range of hydrogen lines in individual quasars. From the measured Lyman fluxes, coupled with Balmer and Paschen line fluxes measured in these same objects, an effort was made to establish observational constraints that would guide models of the broad emission line regions of quasars. It was found that IUE spectra were generally of sufficiently high quality to derive line profiles of the ultraviolet lines Lyman alpha and CIV 1550 A, which were compared to the Balmer line profiles. The objects observed and the line fluxes are tabulated. Plots of line profiles are included.

Phenomenology of spectrally and temporally resolved infrared emissions from bomb detonations

NASA Astrophysics Data System (ADS)

Gross, Kevin; Dills, Anthony; Tuttle, Ron; Perram, Glen

2002-10-01

The remote sensing of infrared signatures from exothermic reactions during military operations, including missile launches, muzzle flashes, and bomb detonations has been studied using fast FTIR techniques. Battle space characterization includes the ability to classify the munitions type, size, and other characteristics. One possible approach to munitions classification is to understand the spectral and temporal signatures from explosive ordinance. To investigate this possibility, experimental data has been collected remotely from ground-based sensors, processed, and analyzed for several conventional munitions. Field observations of 56 detonation events included a set of aircraft delivered ordnance and a series of static ground detonations for a variety of bomb sizes, types and environmental conditions. The emission is well represented by a gray body with continuously decreasing temperature and characteristic decay times of 1-4 s, providing only limited variability with detonation conditions. However, the fireball size times the emissivity as a function of time can be determined from the spectra without imaging and provides a more sensitive signature. The degree of temporal overlap as a function of frequency for a pair of detonation events provides a very sensitive discriminator for explosion conditions. The temporal overlap decreases with increasing emission frequency for all the observed events, indicating more information content at higher frequencies. Finally, the temporal nature of the emissions has been analyzed, providing a significant reduction in the dimensionality of the data.

The Subarcsecond Mid-infrared View of Local Active Galactic Nuclei. III. Polar Dust Emission

NASA Astrophysics Data System (ADS)

Asmus, D.; Hönig, S. F.; Gandhi, P.

2016-05-01

Recent mid-infrared (MIR) interferometric observations have shown that in a few active galactic nuclei (AGNs) the bulk of the infrared emission originates from the polar region above the putative torus, where only a little dust should be present. Here, we investigate whether such strong polar dust emission is common in AGNs. Out of 149 Seyferts in the MIR atlas of local AGNs, 21 show extended MIR emission on single-dish images. In 18 objects, the extended MIR emission aligns with the position angle (PA) of the system axis, established by [O III], radio, polarization, and maser-based PA measurements. The relative amount of resolved MIR emission is at least 40% and scales with the [O IV] fluxes, implying a strong connection between the extended continuum and [O IV] emitters. These results together with the radio-quiet nature of the Seyferts support the scenario that the bulk of MIR emission is emitted by dust in the polar region and not by the torus, which would demand a new paradigm for the infrared emission structure in AGNs. The current low detection rate of polar dust in the AGNs of the MIR atlas is explained by the lack of sufficient high-quality MIR data and the requirements on the orientation, strength of narrow-line region, and distance of the AGNs. The James Webb Space Telescope will enable much deeper nuclear MIR studies with comparable angular resolution, allowing us to resolve the polar emission and surroundings in most of the nearby AGNs. Based on European Southern Observatory (ESO) observing programmes 60.A-9242, 074.A-9016, 075.B-0182, 075.B-0621, 075.B-0631, 075.B-0727, 075.B-0791, 075.B-0844, 076.B-0194, 076.B-0468, 076.B-0599, 076.B-0621, 076.B-0656, 076.B-0696, 076.B-0743, 077.B-0060, 077.B-0135, 077.B-0137, 077.B-0728, 078.B-0020, 078.B-0173, 078.B-0255, 078.B-0303, 080.B-0240, 080.B-0860, 081.B-0182, 082.B-0299, 083.B-0239, 083.B-0452, 083.B-0536, 083.B-0592, 084.B-0366, 084.B-0606, 084.B-0974, 085.B-0251, 085.B-0639, 086.B-0242, 086.B-0257, 086

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.

OBSERVED ASTEROID SURFACE AREA IN THE THERMAL INFRARED

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nugent, C. R.; Mainzer, A.; Masiero, J.

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

Stratospheric distribution of HCN from far infrared observations

NASA Technical Reports Server (NTRS)

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

1987-01-01

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

DUST AROUND R CORONAE BOREALIS STARS. II. INFRARED EMISSION FEATURES IN AN H-POOR ENVIRONMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia-Hernandez, D. A.; Rao, N. Kameswara; Lambert, D. L., E-mail: agarcia@iac.es, E-mail: nkrao@iiap.res.in, E-mail: dll@astro.as.utexas.edu

2013-08-20

Residual Spitzer/Infrared Spectrograph spectra for a sample of 31 R Coronae Borealis (RCB) stars are presented and discussed in terms of narrow emission features superimposed on the quasi-blackbody continuous infrared emission. A broad {approx}6-10 {mu}m dust emission complex is seen in the RCBs showing an extreme H-deficiency. A secondary and much weaker {approx}11.5-15 {mu}m broad emission feature is detected in a few RCBs with the strongest {approx}6-10 {mu}m dust complex. The Spitzer infrared spectra reveal for the first time the structure within the {approx}6-10 {mu}m dust complex, showing the presence of strong C-C stretching modes at {approx}6.3 and 8.1 {mu}mmore » as well as of other dust features at {approx}5.9, 6.9, and 7.3 {mu}m, which are attributable to amorphous carbonaceous solids with little or no hydrogen. The few RCBs with only moderate H-deficiencies display the classical ''unidentified infrared bands (UIRs)'' and mid-infrared features from fullerene-related molecules. In general, the characteristics of the RCB infrared emission features are not correlated with the stellar and circumstellar properties, suggesting that the RCB dust features may not be dependent on the present physical conditions around RCB stars. The only exception seems to be the central wavelength of the 6.3 {mu}m feature, which is blueshifted in those RCBs showing also the UIRs, i.e., the RCBs with the smallest H deficiency.« less

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

Hard X-ray emission of the luminous infrared galaxy NGC 6240 as observed by NuSTAR

NASA Astrophysics Data System (ADS)

Puccetti, S.; Comastri, A.; Bauer, F. E.; Brandt, W. N.; Fiore, F.; Harrison, F. A.; Luo, B.; Stern, D.; Urry, C. M.; Alexander, D. M.; Annuar, A.; Arévalo, P.; Baloković, M.; Boggs, S. E.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Gandhi, P.; Hailey, C. J.; Koss, M. J.; La Massa, S.; Marinucci, A.; Ricci, C.; Walton, D. J.; Zappacosta, L.; Zhang, W.

2016-01-01

We present a broadband (~0.3-70 keV) spectral and temporal analysis of NuSTAR observations of the luminous infrared galaxy NGC 6240 combined with archival Chandra, XMM-Newton, and BeppoSAX data. NGC 6240 is a galaxy in a relatively early merger state with two distinct nuclei separated by ~1.̋5. Previous Chandra observations resolved the two nuclei and showed that they are both active and obscured by Compton-thick material. Although they cannot be resolved by NuSTAR, we were able to clearly detect, for the first time, both the primary and the reflection continuum components thanks to the unprecedented quality of the NuSTAR data at energies >10 keV. The NuSTAR hard X-ray spectrum is dominated by the primary continuum piercing through an absorbing column density which is mildly optically thick to Compton scattering (τ ≃ 1.2, NH ~ 1.5 × 1024 cm-2). We detect moderately hard X-ray (>10 keV) flux variability up to 20% on short (15-20 ks) timescales. The amplitude of the variability is largest at ~30 keV and is likely to originate from the primary continuum of the southern nucleus. Nevertheless, the mean hard X-ray flux on longer timescales (years) is relatively constant. Moreover, the two nuclei remain Compton-thick, although we find evidence of variability in the material along the line of sight with column densities NH ≤ 2 × 1023 cm-2 over long (~3-15 yr) timescales. The observed X-ray emission in the NuSTAR energy range is fully consistent with the sum of the best-fit models of the spatially resolved Chandra spectra of the two nuclei.

A Chandra Observation of the Ultraluminous Infrared Galaxy IRAS 19254-7245 (The Superantennae): X-Ray Emission from the Compton-Thick Active Galactic Nucleus and the Diffuse Starburst

NASA Technical Reports Server (NTRS)

Jia, Jianjun; Ptak, Andrew; Heckman, Timothy M.; Braito, Valentina; Reeves, James

2012-01-01

We present a Chandra observation of IRAS 19254-7245, a nearby ultraluminous infrared galaxy also known as the Superantennae. The high spatial resolution of Chandra allows us to disentangle for the first time the diffuse starburst (SB) emission from the embedded Compton-thick active galactic nucleus (AGN) in the southern nucleus. No AGN activity is detected in the northern nucleus. The 2-10 keV spectrum of the AGN emission is fitted by a flat power law (TAU = 1.3) and an He-like Fe Kalpha line with equivalent width 1.5 keV, consistent with previous observations. The Fe K line profile could be resolved as a blend of a neutral 6.4 keV line and an ionized 6.7 keV (He-like) or 6.9 keV (H-like) line. Variability of the neutral line is detected compared with the previous XMM-Newton and Suzaku observations, demonstrating the compact size of the iron line emission. The spectrum of the galaxy-scale extended emission excluding the AGN and other bright point sources is fitted with a thermal component with a best-fit kT of approximately 0.8 keV. The 2-10 keV luminosity of the extended emission is about one order of magnitude lower than that of the AGN. The basic physical and structural properties of the extended emission are fully consistent with a galactic wind being driven by the SB. A candidate ultraluminous X-ray source is detected 8 south of the southern nucleus. The 0.3 - 10 keV luminosity of this off-nuclear point source is approximately 6 x 10(exp 40) erg per second if the emission is isotropic and the source is associated with the Superantennae.

A Chandra Observation of the Ultraluminous Infrared Galaxy IRAS 19254-7245 (THE SUPERANTENNAE): X-Ray Emission From the Compton-Thick Active Galactic Nucleus and the Diffuse Starburst

NASA Technical Reports Server (NTRS)

Jia, Jianjun; Ptak, Andrew Francis; Heckman, Timothy M.; Braito, Valantina; Reeves, James

2012-01-01

We present a Chandra observation of IRAS 19254-7245, a nearby ultraluminous infrared galaxy also known as the Superantennae. The high spatial resolution of Chandra allows us to disentangle for the first time the diffuse starburst (SB) emission from the embedded Compton-thick active galactic nucleus (AGN) in the southern nucleus. No AGN activity is detected in the northern nucleus. The 2-10 keV spectrum of the AGN emission is fitted by a flat power law (G = 1.3) and an He-like Fe Ka line with equivalent width 1.5 keV, consistent with previous observations. The Fe Ka line profile could be resolved as a blend of a neutral 6.4 keV line and an ionized 6.7 keV (He-like) or 6.9 keV (H-like) line. Variability of the neutral line is detected compared with the previous XMM-Newton and Suzaku observations, demonstrating the compact size of the iron line emission. The spectrum of the galaxy-scale extended emission excluding the AGN and other bright point sources is fitted with a thermal component with a best-fit kT of 0.8 keV. The 2-10 keV luminosity of the extended emission is about one order of magnitude lower than that of the AGN. The basic physical and structural properties of the extended emission are fully consistent with a galactic wind being driven by the SB. A candidate ultraluminous X-ray source is detected 8 south of the southern nucleus. The 0.3-10 keV luminosity of this off-nuclear point source is 6 × 1040 erg s-1 if the emission is isotropic and the source is associated with the Superantennae.

Laser-induced down-conversion and infrared phosphorescence emissivity of novel ligand-free perovskite nanomaterials

NASA Astrophysics Data System (ADS)

Ahmed, M. A.; Khafagy, Rasha M.; El-sayed, O.

2014-03-01

For the first time, standalone and ligand-free series of novel rare-earth-based perovskite nanomaterials are used as near infrared (NIR) and mid infrared (MIR) emitters. Nano-sized La0.7Sr0.3M0.1Fe0.9O3; where M = 0, Mn2+, Co2+ or Ni2+ were synthesized using the flash auto-combustion method and characterized using FTIR, FT-Raman, SEM and EDX. Photoluminescence spectra were spontaneously recorded during pumping the samples with 0.5 mW of green laser emitting continuously at 532 nm. La0.7Sr0.3FeO3 (where M = 0) did not result in any infrared emissivity, while intense near and mid infrared down-converted phosphorescence was released from the M-doped samples. The released phosphorescence greatly shifted among the infrared spectral region with changing the doping cation. Ni2+-doped perovskite emitted at the short-wavelength near-infrared region, while Mn2+ and Co2+-doped perovskites emitted at the mid-wavelength infrared region. The detected laser-induced spontaneous parametric down-conversion phosphorescence (SPDC) occurred through a two-photon process by emitting two NIR or MIR photons among a cooperative energy transfer between the La3+ cations and the M2+ cations. Combining SrFeO3 ceramic with both a rare earth cation (RE3+) and a transition metal cation (Mn2+, Co2+ or Ni2+), rather than introducing merely RE3+ cations, greatly improved and controlled the infrared emissivity properties of synthesized perovskites through destroying their crystal symmetry and giving rise to asymmetrical lattice vibration and the nonlinear optical character. The existence of SPDC in the M2+-doped samples verifies their nonlinear character after the absence of this character in La0.7Sr0.3FeO3. Obtained results verify that, for the first time, perovskite nanomaterials are considered as nonlinear optical crystals with intense infrared emissivity at low pumping power of visible wavelengths, which nominates them for photonic applications and requires further studies regarding their lasing

Chandra Observations of Extended X-Ray Emission in ARP 220

NASA Technical Reports Server (NTRS)

McDowell, J. C.; Clements, D. L.; Lamb, S. A.; Shaked, S.; Hearn, N. C.; Colina, L.; Mundell, C.; Borne, K.; Baker, A. C.; Arribas, S.

2003-01-01

We resolve the extended X-ray emission from the prototypical ultraluminous infrared galaxy Arp 220. Extended, faint, edge-brightened, soft X-ray lobes outside the optical galaxy are observed to a distance of 1CL 15 kpc on each side of the nuclear region. Bright plumes inside the optical isophotes coincide with the optical line emission and extend 1 1 kpc from end to end across the nucleus. The data for the plumes cannot be fitted by a single-temperature plasma and display a range of temperatures from 0.2 to 1 keV. The plumes emerge from bright, diffuse circumnuclear emission in the inner 3 kpc centered on the Ha peak, which is displaced from the radio nuclei. There is a close morphological correspondence between the Ha and soft X-ray emission on all spatial scales. We interpret the plumes as a starburst-driven superwind and discuss two interpretations of the emission from the lobes in the context of simulations of the merger dynamics of Arp 220.

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

Spectroscopically forbidden infra-red emission in Au-vertical graphene hybrid nanostructures

NASA Astrophysics Data System (ADS)

Sivadasan, A. K.; Parida, Santanu; Ghosh, Subrata; Pandian, Ramanathaswamy; Dhara, Sandip

2017-11-01

Implementation of Au nanoparticles (NPs) is a subject for frontier plasmonic research due to its fascinating optical properties. Herein, the present study deals with plasmonic assisted emission properties of Au NPs-vertical graphene (VG) hybrid nanostructures. The influence of effective polarizability of Au NPs on the surface enhanced Raman scattering and luminescence properties is investigated. In addition, a remarkable infra-red emission in the hybrid nanostructures is observed and interpreted on the basis of intra-band transitions in Au NPs. The flake-like nanoporous VG structure is invoked for the generation of additional confined photons to impart additional momentum and a gradient of confined excitation energy towards initiating the intra-band transitions of Au NPs. Integrating Au plasmonic materials in three-dimensional VG nanostructures enhances the light-matter interactions. The present study provides a new adaptable plasmonic assisted pathway for optoelectronic and sensing applications.

Optically active substituted polyacetylene@carbon nanotube hybrids: Preparation, characterization and infrared emissivity property study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bu, Xiaohai; Zhou, Yuming, E-mail: ymzhou@seu.edu.cn; Zhang, Tao

Optically active substituted polyacetylene@multiwalled carbon nanotubes (SPA@MWCNTs) nanohybrids were fabricated by wrapping helical SPA copolymers onto the surface of modified nanotubes through ester bonding linkage. SPA copolymer based on chiral phenylalanine and serine was pre-polymerized by a rhodium zwitterion catalyst in THF, and evidently proved to possess strong optical activity and adopt a predominately one-handed helical conformation. Various characterizations including Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM) demonstrated that the SPA had been covalently grafted onto the nanotubes without destroying their original graphite structure. The wrapped SPA was found tomore » exhibit an enhancement in thermal stability and still maintained considerable optical activity after grafting. The infrared emissivity property of the nanohybrids at 8–14 μm was investigated in addition. The results indicated that the SPA@MWCNTs hybrid matrix could possess a much lower infrared emissivity value (ε=0.707) than raw MWCNTs, which might be due to synergistic effect of the unique helical conformation of optically active SPA and strengthened interfacial interaction between the organic polymers and inorganic nanoparticles. - Graphical abstract: Optically active SPA@MWCNTs nanohybrids with low infrared emissivity. - Highlights: • Synthesis of optically active SPA copolymer derived from serine and phenylalanine. • Preparation and characterization of optically active SPA@MWCNTs nanohybrids. • Application study of the SPA@MWCNTs nanohybrids (ε=0.707) in lowering the infrared emissivity.« less

Ground-based detection of the near-infrared emission from the dayside of WASP-5b

NASA Astrophysics Data System (ADS)

Chen, G.; van Boekel, R.; Madhusudhan, N.; Wang, H.; Nikolov, N.; Seemann, U.; Henning, Th.

2014-04-01

Context. Observations of secondary eclipses of hot Jupiters allow one to measure the dayside thermal emission from the planets' atmospheres. The combination of ground-based near-infrared observations and space-based observations at longer wavelengths constrains the atmospheric temperature structure and chemical composition. Aims: This work aims at detecting the thermal emission of WASP-5b, a highly irradiated dense hot Jupiter orbiting a G4V star every 1.6 days, in the J, H and K near-infrared photometric bands. The spectral energy distribution is used to constrain the temperature-pressure profile and to study the energy budget of WASP-5b. Methods: We observed two secondary-eclipse events of WASP-5b in the J, H, K bands simultaneously using the GROND instrument on the MPG/ESO 2.2 m telescope. The telescope was in nodding mode for the first observation and in staring mode for the second observation. The occultation light curves were modeled to obtain the flux ratios in each band, which were then compared with atmospheric models. Results: Thermal emission of WASP-5b is detected in the J and K bands in staring mode. The retrieved planet-to-star flux ratios are 0.168-0.052+0.050% in the J band and 0.269 ± 0.062% in the K band, corresponding to brightness temperatures of 2996-261+212 K and 2890-269+246 K, respectively. No thermal emission is detected in the H band, with a 3σ upper limit of 0.166% on the planet-to-star flux ratio, corresponding to a maximum temperature of 2779 K. On the whole, our J, H, K results can be explained by a roughly isothermal temperature profile of ~2700 K in the deep layers of the planetary dayside atmosphere that are probed at these wavelengths. Together with Spitzer observations, which probe higher layers that are found to be at ~1900 K, a temperature inversion is ruled out in the range of pressures probed by the combined data set. While an oxygen-rich model is unable to explain all the data, a carbon-rich model provides a reasonable fit

Near-infrared emission from mesoporous crystalline germanium

NASA Astrophysics Data System (ADS)

Boucherif, Abderraouf; Korinek, Andreas; Aimez, Vincent; Arès, Richard

2014-10-01

Mesoporous crystalline germanium was fabricated by bipolar electrochemical etching of Ge wafer in HF-based electrolyte. It yields uniform mesoporous germanium layers composed of high density of crystallites with an average size 5-7 nm. Subsequent extended chemical etching allows tuning of crystallites size while preserving the same chemical composition. This highly controllable nanostructure exhibits photoluminescence emission above the bulk Ge bandgap, in the near-infrared range (1095-1360nm) with strong evidence of quantum confinement within the crystallites.

Far-infrared surface emissivity and climate.

PubMed

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

2014-11-18

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

Far-infrared surface emissivity and climate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feldman, Daniel R.; Collins, William D.; Pincus, Robert

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

Far-infrared surface emissivity and climate

PubMed Central

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

2014-01-01

Presently, there are no global measurement constraints on the surface emissivity at wavelengths longer than 15 μm, even though this surface property in this far-IR region has a direct impact on the outgoing longwave radiation (OLR) and infrared cooling rates where the column precipitable water vapor (PWV) is less than 1 mm. Such dry conditions are common for high-altitude and high-latitude locations, with the potential for modeled climate to be impacted by uncertain surface characteristics. This paper explores the sensitivity of instantaneous OLR and cooling rates to changes in far-IR surface emissivity and how this unconstrained property impacts climate model projections. At high latitudes and altitudes, a 0.05 change in emissivity due to mineralogy and snow grain size can cause a 1.8–2.0 W m−2 difference in the instantaneous clear-sky OLR. A variety of radiative transfer techniques have been used to model the far-IR spectral emissivities of surface types defined by the International Geosphere-Biosphere Program. Incorporating these far-IR surface emissivities into the Representative Concentration Pathway (RCP) 8.5 scenario of the Community Earth System Model leads to discernible changes in the spatial patterns of surface temperature, OLR, and frozen surface extent. The model results differ at high latitudes by as much as 2°K, 10 W m−2, and 15%, respectively, after only 25 y of integration. Additionally, the calculated difference in far-IR emissivity between ocean and sea ice of between 0.1 and 0.2, suggests the potential for a far-IR positive feedback for polar climate change. PMID:25368189

Far-infrared surface emissivity and climate

DOE PAGES

Feldman, Daniel R.; Collins, William D.; Pincus, Robert; ...

2014-11-03

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

Measurement of Far-Infrared Paint Emissivity for Reference Blackbody Modeling and Design

NASA Astrophysics Data System (ADS)

Kaplan, S. G.; Hanssen, L. M.; Mekhontsev, S. N.

2008-12-01

Blackbody sources are typically used for both ground-based and on-orbit calibration of infrared radiometers for atmospheric sounding. Accurate knowledge of the emissivity (or reflectivity) of the painted cavity surfaces is important for the design and modeling of the blackbody performance. Devices designed for the mid- to long-wave infrared (2 μm to 100 μm) generally use specular black paint and multiple (4 to 6) bounces to achieve high emissivity and uniform radiance over the required optical extent. To meet the CLARREO goal of long-term climate monitoring with an absolute uncertainty of < 0.1 K (3 σ), it will be necessary to calibrate radiance measurements to < 0.1 % uncertainty, which could require knowledge of paint emissivity with < 0.005 uncertainty at long wavelength. Critical material parameters include the dependence of emissivity on wavelength, angle of incidence, polarization, and temperature (200 K to 350 K), as well as contributions of scattered light. We present measurement methods and results in support of the CORSAIR SI-traceable far-infrared blackbody design, including temperature-dependent specular reflectance measurements out to 100 μm and angle-dependent data out to 25 μm. In addition, we describe the design for a proposed new facility at NIST (CBS3) that will enable hemispherical-directional emittance and reflectance measurements versus temperature and angle out to 100 μm.

The Evolution of Interstellar Medium Mass Probed by Dust Emission: ALMA Observations at z = 0.3-2

NASA Astrophysics Data System (ADS)

Scoville, N.; Aussel, H.; Sheth, K.; Scott, K. S.; Sanders, D.; Ivison, R.; Pope, A.; Capak, P.; Vanden Bout, P.; Manohar, S.; Kartaltepe, J.; Robertson, B.; Lilly, S.

2014-03-01

The use of submillimeter dust continuum emission to probe the mass of interstellar dust and gas in galaxies is empirically calibrated using samples of local star-forming galaxies, Planck observations of the Milky Way, and high-redshift submillimeter galaxies. All of these objects suggest a similar calibration, strongly supporting the view that the Rayleigh-Jeans tail of the dust emission can be used as an accurate and very fast probe of the interstellar medium (ISM) in galaxies. We present ALMA Cycle 0 observations of the Band 7 (350 GHz) dust emission in 107 galaxies from z = 0.2 to 2.5. Three samples of galaxies with a total of 101 galaxies were stellar-mass-selected from COSMOS to have M * ~= 1011 M ⊙: 37 at z ~ 0.4, 33 at z ~ 0.9, and 31 at z = 2. A fourth sample with six infrared-luminous galaxies at z = 2 was observed for comparison with the purely mass-selected samples. From the fluxes detected in the stacked images for each sample, we find that the ISM content has decreased by a factor ~6 from 1 to 2 × 1010 M ⊙ at both z = 2 and 0.9 down to ~2 × 109 M ⊙ at z = 0.4. The infrared-luminous sample at z = 2 shows a further ~4 times increase in M ISM compared with the equivalent non-infrared-bright sample at the same redshift. The gas mass fractions are ~2% ± 0.5%, 12% ± 3%, 14% ± 2%, and 53% ± 3% for the four subsamples (z = 0.4, 0.9, and 2 and infrared-bright galaxies).

TESTING THE HYPOTHESIS THAT METHANOL MASER RINGS TRACE CIRCUMSTELLAR DISKS: HIGH-RESOLUTION NEAR-INFRARED AND MID-INFRARED IMAGING

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Buizer, James M.; Bartkiewicz, Anna; Szymczak, Marian, E-mail: jdebuizer@sofia.usra.edu

2012-08-01

Milliarcsecond very long baseline interferometry maps of regions containing 6.7 GHz methanol maser emission have lead to the recent discovery of ring-like distributions of maser spots and the plausible hypothesis that they may be tracing circumstellar disks around forming high-mass stars. We aimed to test this hypothesis by imaging these regions in the near- and mid-infrared at high spatial resolution and compare the observed emission to the expected infrared morphologies as inferred from the geometries of the maser rings. In the near-infrared we used the Gemini North adaptive optics system of ALTAIR/NIRI, while in the mid-infrared we used the combinationmore » of the Gemini South instrument T-ReCS and super-resolution techniques. Resultant images had a resolution of {approx}150 mas in both the near-infrared and mid-infrared. We discuss the expected distribution of circumstellar material around young and massive accreting (proto)stars and what infrared emission geometries would be expected for the different maser ring orientations under the assumption that the masers are coming from within circumstellar disks. Based upon the observed infrared emission geometries for the four targets in our sample and the results of spectral energy distribution modeling of the massive young stellar objects associated with the maser rings, we do not find compelling evidence in support of the hypothesis that methanol masers rings reside in circumstellar disks.« less

Observations of far-infrared fine structure lines: o III88.35 micrometer and oI 63.2 micrometer

NASA Technical Reports Server (NTRS)

Storey, J. W. V.; Watson, D. M.; Townes, C. H.

1979-01-01

Observations of the O III 88.35 micrometer line and the O I63.2 micrometer were made with a far infrared spectrometer. The sources M17, NGC 7538, and W51 were mapped in the O III line with 1 arc minute resolution and the emission is found to be quite widespread. In all cases the peak of the emission coincides with the maximum radio continuum. The far infrared continuum was mapped simultaneously and in M17, NGC 7538, and W51 the continuum peak is found to be distinct from the center of ionization. The O III line was also detected in W3, W49, and in a number of positions in the Orion nebula. Upper limits were obtained on NGS 7027, NGC 6572, DR21, G29.9-0.0 and M82. The 63.2 micrometer O I line was detected in M17, M42, and marginally in DR21. A partial map of M42 in this line shows that most of the emission observed arises from the Trapezium and from the bright optical bar to the southeast.

ON THE ORIGIN OF THE 11.3 MICRON UNIDENTIFIED INFRARED EMISSION FEATURE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadjadi, SeyedAbdolreza; Zhang, Yong; Kwok, Sun, E-mail: sunkwok@hku.hk

2015-07-01

The 11.3 μm emission feature is a prominent member of the family of unidentified infrared emission (UIE) bands and is frequently attributed to out-of-plane bending modes of polycyclic aromatic hydrocarbon (PAH) molecules. We have performed quantum mechanical calculations of 60 neutral PAH molecules and found that it is difficult to reconcile the observed astronomical feature with any or a mix of these PAH molecules. We have further analyzed the fitting of spectra of several astronomical objects by the NASA PAH database program and found that reasonable fittings to the observed spectra are only possible by including significant contributions from oxygen-more » and/or magnesium-containing molecules in the mix. A mix of pure PAH molecules, even including units of different sizes, geometry, and charged states, is unable to fit the astronomical spectra. Preliminary theoretical results on the vibrational spectra of simple molecules with mixed aromatic/aliphatic structures show that these structures have consistent clusters of vibrational modes and could be viable carriers of the UIE bands.« less

Inversion of AMSR-E observations for land surface temperature estimation: 2. Global comparison with infrared satellite temperature

NASA Astrophysics Data System (ADS)

Ermida, S. L.; Jiménez, C.; Prigent, C.; Trigo, I. F.; DaCamara, C. C.

2017-03-01

A comparison of land surface temperature (Ts) derived from the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) with infrared Ts is presented. The infrared Ts include clear-sky estimates from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Spinning Enhanced Visible and Infrared Imager, the Geostationary Operational Environmental Satellite (GOES) Imager, and the Japanese Meteorological Imager. The higher discrepancies between AMSR-E and MODIS are observed over deserts and snow-covered areas. The former seems to be associated with Ts underestimation by MODIS, whereas the latter is mostly related to uncertainties in microwave emissivity over snow/ice. Ts differences between AMSR-E and MODIS are significantly reduced after masking out snow and deserts, with a bias change from 2.6/4.6 K to 3.0/1.4 K for daytime/nighttime and a standard deviation (STD) decrease from 7.3/7.9 K to 5.1/3.9 K. When comparing with all infrared sensors, the STD of the differences between microwave and infrared Ts is generally higher than between IR retrievals. However, the biases between microwave and infrared Ts are, in some cases, of the same order as the ones observed between infrared products. This is the case for GOES, with daytime biases with respect to AMSR-E and MODIS of 0.45 K and 0.60 K, respectively. While the infrared Ts are clear-sky estimates, AMSR-E also provides Ts under cloudy conditions. For frequently cloudy regions, this results in a large increase of available Ts estimates (>250%), making the microwave Ts a very powerful complement of the infrared estimates.

ON THE VIABILITY OF THE PAH MODEL AS AN EXPLANATION OF THE UNIDENTIFIED INFRARED EMISSION FEATURES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yong; Kwok, Sun, E-mail: zhangy96@hku.hk, E-mail: sunkwok@hku.hk

2015-01-01

Polycyclic aromatic hydrocarbon (PAH) molecules are widely considered the preferred candidate for the carrier of the unidentified infrared emission bands observed in the interstellar medium and circumstellar envelopes. In this paper, we report the results of fitting a variety of non-PAH spectra (silicates, hydrogenated amorphous carbon, coal, and even artificial spectra) using the theoretical infrared spectra of PAHs from the NASA Ames PAH IR Spectroscopic Database. We show that these non-PAH spectra can be well fitted by PAH mixtures. This suggests that a general match between astronomical spectra and those of PAH mixtures does not necessarily provide definitive support formore » the PAH hypothesis.« less

Constraints on Circumstellar Dust Grain Sizes from High Spatial Resolution Observations in the Thermal Infrared

NASA Technical Reports Server (NTRS)

Bloemhof, E. E.; Danen, R. M.; Gwinn, C. R.

1996-01-01

We describe how high spatial resolution imaging of circumstellar dust at a wavelength of about 10 micron, combined with knowledge of the source spectral energy distribution, can yield useful information about the sizes of the individual dust grains responsible for the infrared emission. Much can be learned even when only upper limits to source size are available. In parallel with high-resolution single-telescope imaging that may resolve the more extended mid-infrared sources, we plan to apply these less direct techniques to interpretation of future observations from two-element optical interferometers, where quite general arguments may be made despite only crude imaging capability. Results to date indicate a tendency for circumstellar grain sizes to be rather large compared to the Mathis-Rumpl-Nordsieck size distribution traditionally thought to characterize dust in the general interstellar medium. This may mean that processing of grains after their initial formation and ejection from circumstellar atmospheres adjusts their size distribution to the ISM curve; further mid-infrared observations of grains in various environments would help to confirm this conjecture.

Infrared speckle observations of Io - An eruption in the Loki region

NASA Technical Reports Server (NTRS)

Howell, R. R.; Mcginn, M. T.

1985-01-01

Speckle observations of Jupiter's satellite Io at a wavelength of 5 micrometers during July 1984 resolved the disk and showed emission from a hot spot in the Loki region. The hot spot contributed a flux approximately equal to 60 percent of that from the disk. Images reconstructed by means of the Knox-Thompson algorithm showed the spot moving across the disk as the satellite rotated. It was located at 301 deg + or - 6 deg west longitude, 10 deg + or - 6 deg north latitude, and had a radiance of (2.96 + or - 0.54) x 10 to the 22nd ergs/sec cm sr/A where A is the area of the spot. For an assumed temperature of 400 K, the area of the source would be 11,400 square kilometers. An active 'lava lake' similar to that seen by Voyager may be the source of the infrared emission.

Infrared speckle observations of Io - an eruption in the Loki region

NASA Astrophysics Data System (ADS)

Howell, R. R.; McGinn, M. T.

1985-10-01

Speckle observations of Jupiter's satellite Io at a wavelength of 5 micrometers during July 1984 resolved the disk and showed emission from a hot spot in the Loki region. The hot spot contributed a flux approximately equal to 60 percent of that from the disk. Images reconstructed by means of the Knox-Thompson algorithm showed the spot moving across the disk as the satellite rotated. It was located at 301 deg + or - 6 deg west longitude, 10 deg + or - 6 deg north latitude, and had a radiance of (2.96 + or - 0.54) x 10 to the 22nd ergs/sec cm sr/A where A is the area of the spot. For an assumed temperature of 400 K, the area of the source would be 11,400 square kilometers. An active 'lava lake' similar to that seen by Voyager may be the source of the infrared emission.

Observed Barium Emission Rates

NASA Technical Reports Server (NTRS)

Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

1993-01-01

The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

HAWC+/SOFIA observations of Rho Oph A: far-infrared polarization spectrum

NASA Astrophysics Data System (ADS)

Santos, Fabio; Dowell, Charles D.; Houde, Martin; Looney, Leslie; Lopez-Rodriguez, Enrique; Novak, Giles; Ward-Thompson, Derek; HAWC+ Science Team

2018-01-01

In this work, we present preliminary results from the HAWC+ far-infrared polarimeter that operates on the SOFIA airborne observatory. The densest portions of the Rho Ophiuchi molecular complex, known as Rho Oph A, have been mapped using HAWC+ bands C (89 microns) and D (155 microns). Rho Oph A is a well known nearby star forming region. At the target's distance of approximately 130 pc, our observations provide excellent spatial resolution (~5 mpc in band C).The magnetic field map suggests a compressed and distorted field morphology around Oph S1, a massive B3 star that is the main heat source of Rho Oph A. We compute the ratio p(D)/p(C), where p(C) and p(D) are the polarization degree maps at bands C and D, respectively. This ratio estimates the slope of the polarization spectrum in the far-infrared. Although the slope is predicted to be positive by dust grain models, previous observations of other molecular clouds have revealed that negative slopes are common. In Rho Oph A, we find that there is a smooth gradient of p(D)/p(C) across the mapped field. The change in p(D)/p(C) is well correlated with the integrated NH3 (1,1) emission. A positive slope dominates the lower density and well illuminated portions of the cloud, whereas a transition to a negative slope is observed at the denser and less evenly illuminated cloud core.We interpret the positive to negative slope transition as being consistent with the radiative torques (RATs) grain alignment theory. For the sight lines of higher column density, polarized emission from the warmer outer cloud layers is added to emission from the colder inner well-shielded layers lying along the same line-of-sight. Given that the outer layers receive more radiation from Oph S1, their grain alignment efficiency is expected to be higher according to RATs. The combination of warmer, well aligned grains with cooler, poorly aligned grains is what causes the negative slope. This effect is not present in the sight lines of lower column

Do the Infrared Emission Features Need UV Excitation? The PAH Model in UV-poor Reflection Nebulae

NASA Astrophysics Data System (ADS)

Li, A.; Draine, B. T.

2001-12-01

One of the major challenges of identifying the 3.3, 6.2, 7.7, 8.6, and 11.3μ m interstellar infrared emission bands with polycyclic aromatic hydrocarbon (PAH) molecules has been the recent detection of these bands in regions with little ultraviolet (UV) illumination since small, neutral PAH molecules have little or no absorption at visible wavelengths and thus are excited primarily by UV photons. The ``astronomical'' PAH model (Li & Draine 2001), incorporating the experimental result that the visual absorption edge shifts to longer wavelength upon ionization and/or as the PAH size increases (Allamandola, Hudgins, & Sandford 1999), is shown to be able to closely reproduce the observed infrared emission bands of vdB 133, a UV-poor reflection nebula (Uchida, Sellgren, & Werner 1998) as well as the 6.2, 7.7, and 11.3μ m band ratios of the UV-deficient ring in the Andromeda galaxy M31 (Pagani et al. 1999). It is also shown that ``astronomical'' PAHs can be heated sufficiently by a T eff=3000 K black-body to emit at 6.2, 7.7, 8.6, and 11.3μ m. Illustrative mid-IR emission spectra are calculated for reflection nebulae illuminated by cool stars with T eff=3600, 4500, 5000 K. These will allow comparison with future Space Infrared Telescope Facility (SIRTF) observations of vdB 135 (T eff=3600 K), vdB 47 (T eff=4500 K), and vdB 101 (T eff=5000 K) (Houck 2001). This research was supported in part by NASA grant NAG5-7030 and NSF grant AST-9619429. { References:} Allamandola, L.J., Hudgins, D.M., & Sandford, S.A. 1999, ApJ, 511, L115 Houck, J.R. 2001, SIRTF Observations of the Mid IR Features in Reflection Nebulae, {\\sf http://sirtf.caltech.edu/ROC/pid19} Li, A., & Draine, B.T. 2001, ApJ, 554, 778 Pagani, L., et al. 1999, A&A, 351, 447 Uchida, K.I., Sellgren, K., & Werner, M.W. 1998, ApJ, 493, L109

The Far-Infrared Spectral Energy Distributions of Quasars

NASA Technical Reports Server (NTRS)

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

2001-01-01

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

Infrared coronal emission lines and the possibility of their laser emission in Seyfert nuclei

NASA Technical Reports Server (NTRS)

Greenhouse, Matthew A.; Feldman, Uri; Smith, Howard A.; Klapisch, Marcel; Bhatia, Anand K.; Bar-Shalom, Avi

1993-01-01

Results are presented from detailed balance calculations, and a compilation of atomic data and other model calculations designed to support upcoming ISO and current observing programs involving IR coronal emission lines, together with a table with a complete line list of infrared transitions within the ground configurations 2s2 2p(k), 3s2 3p(k), and the first excited configurations 2s 2p and 3s 3p of highly ionized astrophysically abundant elements. The temperature and density parameter space for dominant cooling via IR coronal lines is presented, and the relationship of IR and optical coronal lines is discussed. It is found that, under physical conditions found in Seyfert nuclei, 14 of 70 transitions examined have significant population inversions in levels that give rise to IR coronal lines. Several IR coronal line transitions were found to have laser gain lengths that correspond to column densities of 10 exp 24-25/sq cm which are modeled to exist in Seyfert nuclei. Observations that can reveal inverted level populations and laser gain in IR coronal lines are suggested.

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.

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.

Mid-infrared emission and Judd-Ofelt analysis of Dy3+-doped infrared Ga-Sb-S and Ga-Sb-S-PbI2 chalcohalide glasses

NASA Astrophysics Data System (ADS)

Guo, Jixiao; Jiao, Qing; He, Xiaolong; Guo, Hansong; Tong, Jianghao; Zhang, Zhihang; Jiang, Fuchao; Wang, Guoxiang

2018-03-01

Dy3+-doped Ga-Sb-S and Ga-Sb-S-PbI2 chalcohalide glasses were prepared by traditional melt quenching method. The effect of halide PbI2 on the physical and optical properties of Dy3+ ions was investigated. The density and ionic concentration of the host sample increased with the introduction of PbI2 halides, whereas the refractive index at 1.55 μm decreased. The Judd-Ofelt parameters showed that Ω2 increased in PbI2-modified glass, whereas the Ω6 value showed the opposite tendency. Infrared emission spectrum also showed that the intensity increased with PbI2 addition, and considerable enhancement at 2.8 μm was observed in the mid-infrared region. The halide PbI2 promoted the reduction of phonon energy of the host and the improvement of the laser pump efficiency, which led to the construction of optimized infrared glass materials for optical applications.

UNIDENTIFIED INFRARED EMISSION BANDS: PAHs or MAONs?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun Kwok; Yong Zhang, E-mail: sunkwok@hku.hk

2013-07-01

We suggest that the carrier of the unidentified infrared emission (UIE) bands is an amorphous carbonaceous solid with mixed aromatic/aliphatic structures, rather than free-flying polycyclic aromatic hydrocarbon molecules. Through spectral fittings of the astronomical spectra of the UIE bands, we show that a significant amount of the energy is emitted by the aliphatic component, implying that aliphatic groups are an essential part of the chemical structure. Arguments in favor of an amorphous, solid-state structure rather than a gas-phase molecule as a carrier of the UIE are also presented.

Comment on "A spectroscopic comparison of selected Chinese kaolinite, coal bearing kaolinite and halloysite--a mid-infrared and near-infrared study" and "Infrared and infrared emission spectroscopic study of typical Chinese kaolinite and halloysite" by Hongfei Cheng et al. (2010).

PubMed

Kloprogge, J Theo

2015-02-05

In two papers Cheng et al. (2010) reported in this journal on the mid-infrared, near-infrared and infrared emission spectroscopy of a halloysite from Hunan Xianrenwan, China. This halloysite contains around 8% of quartz (SiO2) and nearly 9% gibbsite (Al(OH)3). In their interpretation of the spectra these impurities were completely ignored. Careful comparison with a phase pure halloysite from Southern Belgium, synthetic gibbsite, gibbsite from Minas Gerais, and quartz show that these impurities do have a marked influence on the mid-infrared and infrared emission spectra. In the near-infrared, the effect is much less pronounced. Quartz does not show bands in this region and the gibbsite bands will be very weak. Comparison still show that the presence of gibbsite does contribute to the overall spectrum and bands that were ascribed to the halloysite alone do coincide with those of gibbsite. Copyright © 2014 Elsevier B.V. All rights reserved.

DUST AROUND R CORONAE BOREALIS STARS. I. SPITZER/INFRARED SPECTROGRAPH OBSERVATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anibal Garcia-Hernandez, D.; Kameswara Rao, N.; Lambert, David L., E-mail: agarcia@iac.es, E-mail: nkrao@iiap.res.in, E-mail: dll@astro.as.utexas.edu

2011-09-20

Spitzer/infrared spectrograph (IRS) spectra from 5 to 37 {mu}m 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 {mu}mmore » and 25 {mu}m 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 {mu}m luminosity and [8.0]-[24.0] color index.« less

Design and calculation of low infrared transmittance and low emissivity coatings for heat radiative applications

NASA Astrophysics Data System (ADS)

Wang, Guang-Hai; Zhang, Yue; Zhang, Da-Hai; Fan, Jin-Peng

2012-02-01

The infrared transmittance and emissivity of heat-insulating coatings pigmented with various structural particles were studied using Kubelka-Munk theory and Mie theory. The primary design purpose was to obtain the low transmittance and low emissivity coatings to reduce the heat transfer by thermal radiation for high-temperature applications. In the case of silica coating layers constituted with various structural titania particles (solid, hollow, and core-shell spherical), the dependence of transmittance and emissivity of the coating layer on the particle structure and the layer thickness was investigated and optimized. The results indicate that the coating pigmented with core-shell titania particles exhibits a lower infrared transmittance and a lower emissivity value than that with other structural particles and is suitable to radiative heat-insulating applications.

Unpolarized infrared emissivity with shadow from anisotropic rough sea surfaces with non-Gaussian statistics.

PubMed

Bourlier, Christophe

2005-07-10

The emissivity of two-dimensional anisotropic rough sea surfaces with non-Gaussian statistics is investigated. The emissivity derivation is of importance for retrieval of the sea-surface temperature or equivalent temperature of a rough sea surface by infrared thermal imaging. The well-known Cox-Munk slope probability-density function, considered non-Gaussian, is used for the emissivity derivation, in which the skewness and the kurtosis (related to the third- and fourth-order statistics, respectively) are included. The shadowing effect, which is significant for grazing angles, is also taken into account. The geometric optics approximation is assumed to be valid, which means that the rough surface is modeled as a collection of facets reflecting locally the light in the specular direction. In addition, multiple reflections are ignored. Numerical results of the emissivity are presented for Gaussian and non-Gaussian statistics, for moderate wind speeds, for near-infrared wavelengths, for emission angles ranging from 0 degrees (nadir) to 90 degrees (horizon), and according to the wind direction. In addition, the emissivity is compared with both measurements and a Monte Carlo ray-tracing method.

Performance limitations of temperature-emissivity separation techniques in long-wave infrared hyperspectral imaging applications

NASA Astrophysics Data System (ADS)

Pieper, Michael; Manolakis, Dimitris; Truslow, Eric; Cooley, Thomas; Brueggeman, Michael; Jacobson, John; Weisner, Andrew

2017-08-01

Accurate estimation or retrieval of surface emissivity from long-wave infrared or thermal infrared (TIR) hyperspectral imaging data acquired by airborne or spaceborne sensors is necessary for many scientific and defense applications. This process consists of two interwoven steps: atmospheric compensation and temperature-emissivity separation (TES). The most widely used TES algorithms for hyperspectral imaging data assume that the emissivity spectra for solids are smooth compared to the atmospheric transmission function. We develop a model to explain and evaluate the performance of TES algorithms using a smoothing approach. Based on this model, we identify three sources of error: the smoothing error of the emissivity spectrum, the emissivity error from using the incorrect temperature, and the errors caused by sensor noise. For each TES smoothing technique, we analyze the bias and variability of the temperature errors, which translate to emissivity errors. The performance model explains how the errors interact to generate temperature errors. Since we assume exact knowledge of the atmosphere, the presented results provide an upper bound on the performance of TES algorithms based on the smoothness assumption.

Relative emission-line strengths for the 146 and 63 micron transitions in O I and a comparison with far-infrared observations of photodissociation regions

NASA Astrophysics Data System (ADS)

Keenan, F. P.; Conlon, E. S.; Rubin, R. H.

1994-10-01

Theoretical O I density-sensitive emission-line ratios R = I(2s2)(2p4)(3P0)-((2s2)(2p4)(3P1))/I((2s2)(2p4)(3P1)-(2s2)(2p4)(3P2)) = I(146 micrometers)/I(63 micrometers) are presented for a range of temperatures (T = 100-10,000 K), neutral hydrogen densities (NH = 10-2 to 107/cu cm) and radiation fields (G0 = 1-106) applicable to both photodissociation regions (PDRs) and H II regions and the diffuse ionized medium (DIM). The observed values of R for several PDRs, measured from far-infrared spectra obtained with the Kuiper Airborne Observatory (KAO), imply hydrogen densities which are in good agreement with those determined using other methods. This provides observational support for the validity of the theoretical O I line ratios, and hence the atomic data used in their derivation.

Mid-infrared emissions of Pr{sup 3+}-doped GeS{sub 2}–Ga{sub 2}S{sub 3}–CdI{sub 2} chalcohalide glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Chunfeng; Guo, Haitao, E-mail: guoht_001@opt.ac.cn; Xu, Yantao

2014-12-15

Graphical abstract: ∼4.6 μm mid-infrared fluorescence emission from Pr{sup 3+} in the sulfide glass is successfully observed at room temperature excited by a 2.01 μm Tm{sup 3+}:YAG ceramic laser system. - Highlights: • Serial Pr{sup 3+}-doped GeS{sub 2}–Ga{sub 2}S{sub 3}–CdI{sub 2} chalcohalide glasses were synthesized. • ∼4.6 μm mid-infrared fluorescence from Pr{sup 3+} was observed at room temperature. • The compositional dependence of luminescence properties was studied. • Radiative properties have been determined using the Judd–Ofelt theory. - Abstract: For elucidation of the glass composition’s influence on the spectroscopic properties in the chalcohalide system and the discovery of a newmore » material for applications in mid-infrared fiber-lasers, a serial Pr{sup 3+}-doped (100 − x)(0.8GeS{sub 2}·0.2Ga{sub 2}S{sub 3})xCdI{sub 2} (x = 5, 10, 15 and 20) chalcohalide glasses were prepared. ∼4.6 μm mid-infrared fluorescence emission from Pr{sup 3+} in the sulfide glass is successfully observed at room temperature excited by a 2.01 μm Tm{sup 3+}:YAG ceramic laser system, and the effective line-width of fluorescence band is 106–227 nm. Intense compositional dependence of mid-infrared emissions is found. The radiative rates of Pr{sup 3+} ions in these glasses were calculated by using the Judd–Ofelt theory.« less

ALMA Multiple-transition Observations of High-density Molecular Tracers in Ultraluminous Infrared Galaxies

NASA Astrophysics Data System (ADS)

Imanishi, Masatoshi; Nakanishi, Kouichiro; Izumi, Takuma

2018-04-01

We present the results of our ALMA observations of 11 (ultra)luminous infrared galaxies ((U)LIRGs) at J = 4–3 of HCN, HCO+, and HNC and J = 3–2 of HNC. This is an extension of our previously published HCN and HCO+ J = 3–2 observations to multiple rotational J-transitions of multiple molecules, to investigate how molecular emission line flux ratios vary at different J-transitions. We confirm that ultraluminous infrared galaxies (ULIRGs) that contain or may contain luminous obscured active galactic nuclei (AGNs) tend to show higher HCN-to-HCO+ flux ratios than starburst galaxies, both at J = 4–3 and J = 3–2. For selected HCN-flux-enhanced AGN-important ULIRGs, our isotopologue H13CN, H13CO+, and HN13C J = 3–2 line observations suggest a higher abundance of HCN than HCO+ and HNC, which is interpreted to be primarily responsible for the elevated HCN flux in AGN-important galaxies. For such sources, the intrinsic HCN-to-HCO+ flux ratios after line opacity correction will be higher than the observed ratios, making the separation between AGNs and starbursts even larger. The signature of the vibrationally excited (v 2 = 1f) HCN J = 4–3 emission line is seen in one ULIRG, IRAS 12112‑0305 NE. P Cygni profiles are detected in the HCO+ J = 4–3 and J = 3–2 lines toward IRAS 15250+3609, with an estimated molecular outflow rate of ∼250–750 M ⊙ yr‑1. The SiO J = 6–5 line also exhibits a P Cygni profile in IRAS 12112+0305 NE, suggesting the presence of shocked outflow activity. Shock tracers are detected in many sources, suggesting ubiquitous shock activity in the nearby ULIRG population.

Effect of nano-sized cerium-zirconium oxide solid solution on far-infrared emission properties of tourmaline powders

NASA Astrophysics Data System (ADS)

Guo, Bin; Yang, Liqing; Hu, Weijie; Li, Wenlong; Wang, Haojing

2015-10-01

Far-infrared functional nanocomposites were prepared by the co-precipitation method using natural tourmaline (XY3Z6Si6O18(BO3)3V3W, where X is Na+, Ca2+, K+, or vacancy; Y is Mg2+, Fe2+, Mn2+, Al3+, Fe3+, Mn3+, Cr3+, Li+, or Ti4+; Z is Al3+, Mg2+, Cr3+, or V3+; V is O2-, OH-; and W is O2-, OH-, or F-) powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample, tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that tourmaline modified with Ce and Zr has a better far-infrared emission property than tourmaline modified with Ce alone. Through characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the mechanism for oxygen evolution during the heat process in the two composite materials was systematically studied. The XPS spectra show that Fe3+ ratio inside tourmaline modified with Ce alone can be raised by doping Zr. Moreover, it is showed that there is a higher Ce3+ ratio inside the tourmaline modified with Ce and Zr than tourmaline modified with Ce alone. In addition, XRD results indicate the formation of CeO2 and Ce1-xZrxO2 crystallites during the heat treatment and further TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce-Zr doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of Fe2+ to Fe3+ inside the tourmaline caused by the change in the catalyst redox properties of CeO2 brought about by doping with Zr4+. In all samples, tourmaline modified with 7.14 wt.% Ce and 1.86 wt.% Zr calcined at 800∘C for 5 h has the best far-infrared emission property with the maximum emissivity value of 98%.

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).

High Resolution Radio Observations Of Energetically Dominant Regions In Local Luminous Infrared Galaxies

NASA Astrophysics Data System (ADS)

Barcos-Munoz, Loreto

2016-07-01

Luminous and Ultra-luminous Infrared galaxies (U/LIRGs) are one of the most powerful classes of extragalactic objects in the local universe, and they provide a unique opportunity to study star formation and feedback processes in extreme environments. They are primarily observed to be interacting or merging disk galaxies. During the interaction, large amounts of gas are funneled to the central few kpc, triggering high star formation rates (SFR) and dust production. The absorption of UV and optical radiation from stars, or active galactic nuclei (AGN), by dust produces their observed high infrared luminosities.The high level of dust obscuration intrinsic to U/LIRGs makes them difficult to study. Radio interferometry is thus the perfect tool for revealing the nature of these systems - it provides the high spatial resolution needed to resolve energetically dominant regions in U/LIRGs at wavelengths that have both diagnostic power and transparency to dust. In this thesis, 6 and 33 GHz radio continuum interferometric observations with the upgraded Karl G. Jansky Very Large Array (VLA) are used to study a sample of 22 local U/LIRGs.First, a detailed analysis of the 6 and 33 GHz radio continuum emission from the closest ULIRG, Arp 220, is presented. This late stage merger is highly obscured, being optically thick even at mid-infrared wavelengths. Further, due to its extreme environment, it is often used as a template for high redshift starbursts. Arp 220 hosts two distinct nuclei that are separated by (\\sim) 370 pc. The nuclei are well resolved with the 33 GHz observations (i.e., with a spatial resolution of ˜ 30 pc). The deconvolved radii enclosing half of the total 33 GHz light are approximately 50 and 35 pc for the eastern and western nucleus, respectively. Literature values of the gas mass and infrared luminosity are combined with the 33 GHz sizes under the assumption of co-spatiality to show that Arp 220 has one of the highest molecular gas surface densities

ALMA INVESTIGATION OF VIBRATIONALLY EXCITED HCN/HCO{sup +}/HNC EMISSION LINES IN THE AGN-HOSTING ULTRALUMINOUS INFRARED GALAXY IRAS 20551−4250

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imanishi, Masatoshi; Nakanishi, Kouichiro; Izumi, Takuma, E-mail: masa.imanishi@nao.ac.jp

2016-07-01

We present the results of ALMA Cycle 2 observations of the ultraluminous infrared galaxy IRAS 20551−4250 at HCN/HCO{sup +}/HNC J = 3–2 lines at both vibrational ground ( v = 0) and vibrationally excited ( v {sub 2} = 1) levels. This galaxy contains a luminous buried active galactic nucleus (AGN), in addition to starburst activity, and our ALMA Cycle 0 data revealed a tentatively detected vibrationally excited HCN v {sub 2} = 1f J = 4–3 emission line. In our ALMA Cycle 2 data, the HCN/HCO{sup +}/HNC J = 3–2 emission lines at v = 0 are clearly detected.more » The HCN and HNC v {sub 2} = 1f J = 3–2 emission lines are also detected, but the HCO{sup +} v {sub 2} = 1f J = 3–2 emission line is not. Given the high energy level of v {sub 2} = 1 and the resulting difficulty of collisional excitation, we compared these results with those of the calculation of infrared radiative pumping, using the available infrared 5–35 μ m spectrum. We found that all of the observational results were reproduced if the HCN abundance was significantly higher than that of HCO{sup +} and HNC. The flux ratio and excitation temperature between v {sub 2} = 1f and v = 0, after correction for possible line opacity, suggests that infrared radiative pumping affects rotational ( J -level) excitation at v = 0 at least for HCN and HNC. The HCN-to-HCO{sup +} v = 0 flux ratio is higher than those of starburst-dominated regions, and will increase even more when the derived high HCN opacity is corrected. The enhanced HCN-to-HCO{sup +} flux ratio in this AGN-hosting galaxy can be explained by the high HCN-to-HCO{sup +} abundance ratio and sufficient HCN excitation at up to J = 4, rather than the significantly higher efficiency of infrared radiative pumping for HCN than HCO{sup +}.« less

Remote Observations in the Near Infrared

NASA Astrophysics Data System (ADS)

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

We present our experiences in remote observations in Near Infrared bands operating a bidimensional instrument ARNICA. ARNICA, an infrared CCD detector operating at a telescope (TIRGO, Gornergrat, Switzerland) was controlled by an observer from Firenze, Italy. Despite the rather slow Internet link available, we were able to perform the observations in quite an acceptable way. The user interface process (a widget based X11 client) was executed locally on a Sun workstation. All processes responsible for hardware support (initialization of devices and their dynamic control and data acquisition itself) were executed remotely under DESQview/X on a PC dedicated to the control of ARNICA. The traffic was reduced to a minimum due to the truly distributed software used. In normal conditions this is just an exchange of short primitives which describe the task to be performed and of informative messages. There is also the possibility of a continuous display of the obtained images, with flexible control of display parameters.

On the relationship between land surface infrared emissivity and soil moisture

NASA Astrophysics Data System (ADS)

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

2018-01-01

The relationship between surface infrared (IR) emissivity and soil moisture content has been investigated based on satellite measurements. Surface soil moisture content can be estimated by IR remote sensing, namely using the surface parameters of IR emissivity, temperature, vegetation coverage, and soil texture. It is possible to separate IR emissivity from other parameters affecting surface soil moisture estimation. The main objective of this paper is to examine the correlation between land surface IR emissivity and soil moisture. To this end, we have developed a simple yet effective scheme to estimate volumetric soil moisture (VSM) using IR land surface emissivity retrieved from satellite IR spectral radiance measurements, assuming those other parameters impacting the radiative transfer (e.g., temperature, vegetation coverage, and surface roughness) are known for an acceptable time and space reference location. This scheme is applied to a decade of global IR emissivity data retrieved from MetOp-A infrared atmospheric sounding interferometer measurements. The VSM estimated from these IR emissivity data (denoted as IR-VSM) is used to demonstrate its measurement-to-measurement variations. Representative 0.25-deg spatially-gridded monthly-mean IR-VSM global datasets are then assembled to compare with those routinely provided from satellite microwave (MW) multisensor measurements (denoted as MW-VSM), demonstrating VSM spatial variations as well as seasonal-cycles and interannual variability. Initial positive agreement is shown to exist between IR- and MW-VSM (i.e., R2 = 0.85). IR land surface emissivity contains surface water content information. So, when IR measurements are used to estimate soil moisture, this correlation produces results that correspond with those customarily achievable from MW measurements. A decade-long monthly-gridded emissivity atlas is used to estimate IR-VSM, to demonstrate its seasonal-cycle and interannual variation, which is spatially

1.25-mm observations of luminous infrared galaxies

NASA Technical Reports Server (NTRS)

Carico, David P.; Keene, Jocelyn; Soifer, B. T.; Neugebauer, G.

1992-01-01

Measurements at a wavelength of 1.25 mm have been obtained for 17 IRAS galaxies selected on the basis of high far-infrared luminosity. These measurements are used to estimate the lower and upper limits to the mass of cold dust in infrared galaxies. As a lower limit on dust mass, all of the galaxies can be successfully modeled without invoking any dust colder than the dust responsible for the 60 and 100 micron emission that was detected by IRAS. As an upper limit, it is possible that the dust mass in a number of the galaxies may actually be dominated by cold dust. This large difference between the lower and upper limits is due primarily to uncertainty in the long-wavelength absorption efficiency of the astrophysical dust grains.

Effect of gallium environment on infrared emission in Er3+-doped gallium– antimony– sulfur glasses

PubMed Central

Jiao, Qing; Li, Ge; Li, Lini; Lin, Changgui; Wang, Guoxiang; Liu, Zijun; Dai, Shixun; Xu, Tiefeng; Zhang, Qinyuan

2017-01-01

Gallium-based Ga–Sb–S sulfide glasses was elaborated and studied. A relationship between the structure, composition, and optical properties of the glass has been established. The effects of the introduction of Ga on the structure using infrared and Raman spectroscopies and on the Er3+-doped IR emission have been discussed. The results show that incorporation of Ga induced the dissociation of [SbS3] pyramids units and the formation of tetrahedral [GaS4] units. The dissolved rare earth ions are separated around the Ga–S bonding and the infrared emission quenching are controlled. Moreover, continuous introduction of Er ions into the glass forms more Er–S bonds through the further aggregation surrounding the [GaS4] units. In return, the infrared emission intensity decreased with excessive Er ion addition. This phenomenon is correlated with the recurrence concentration quenching effect induced by the increase of [GaS4] units. PMID:28106143

ALMA HCN AND HCO{sup +} J  = 3 − 2 OBSERVATIONS OF OPTICAL SEYFERT AND LUMINOUS INFRARED GALAXIES: CONFIRMATION OF ELEVATED HCN-TO-HCO{sup +} FLUX RATIOS IN AGNS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imanishi, Masatoshi; Nakanishi, Kouichiro; Izumi, Takuma, E-mail: masa.imanishi@nao.ac.jp

We present the results of our ALMA observations of three active galactic nucleus (AGN)-dominated nuclei in optical Seyfert 1 galaxies (NGC 7469, I Zw 1, and IC 4329 A) and eleven luminous infrared galaxies (LIRGs) with various levels of infrared estimated energetic contributions by AGNs at the HCN and HCO{sup +} J  = 3 − 2 emission lines. The HCN and HCO{sup +} J  = 3 − 2 emission lines are clearly detected at the main nuclei of all sources, except for IC 4329 A. The vibrationally excited ( v {sub 2} = 1f) HCN J  = 3 − 2 and HCO{sup +} J  = 3 − 2 emission lines are simultaneouslymore » covered, and HCN v {sub 2} = 1f J  = 3 − 2 emission line signatures are seen in the main nuclei of two LIRGs, IRAS 12112+0305 and IRAS 22491–1808, neither of which shows clear buried AGN signatures in the infrared. If the vibrational excitation is dominated by infrared radiative pumping, through the absorption of infrared 14 μ m photons, primarily originating from AGN-heated hot dust emission, then these two LIRGs may contain infrared-elusive, but (sub)millimeter-detectable, extremely deeply buried AGNs. These vibrationally excited emission lines are not detected in the three AGN-dominated optical Seyfert 1 nuclei. However, the observed HCN v {sub 2} = 1f to v  = 0 flux ratios in these optical Seyferts are still consistent with the intrinsic flux ratios in LIRGs with detectable HCN v {sub 2} = 1f emission lines. The observed HCN-to-HCO{sup +} J  = 3 − 2 flux ratios tend to be higher in galactic nuclei with luminous AGN signatures compared with starburst-dominated regions, as previously seen at J  = 1 − 0 and J  = 4 − 3.« less

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.

A method to quickly test the emissivity with an infrared thermal imaging system within a small distance

NASA Astrophysics Data System (ADS)

Wang, Xuan-yu; Hu, Rui; Wang, Rui-xin

2015-10-01

A simple method has been set up to quickly test the emissivity with an infrared thermal imaging system within a small distance according to the theory of measuring temperature by infrared system, which is based on the Planck radiation law and Lambert-beer law. The object's temperature is promoted and held on by a heater while a temperature difference has been formed between the target and environment. The emissivity of human skin, galvanized iron plate, black rubber and liquid water has been tested under the condition that the emissivity is set in 1.0 and the testing distance is 1m. According to the invariance of human's body temperature, a testing curve is established to describe that the thermal imaging temperatures various with the emissivity which is set in from 0.9 to 1.0. As a result, the method has been verified. The testing results show that the emissivity of human skin is 0.95. The emissivity of galvanized iron plate, black rubber and liquid water decreases with the increase of object's temperature. The emissivity of galvanized iron plate is far smaller than the one of human skin, black rubber or water. The emissivity of water slowly linearly decreases with the increase of its temperature. By the study, within a small distance and clean atmosphere, the infrared emissivity of objects may be expediently tested with an infrared thermal imaging system according to the method, which is promoting the object's temperature to make it different from the environment temperature, then simultaneously measures the environmental temperature, the real temperature and thermal imaging temperature of the object when the emissivity is set in 1.0 and the testing distance is 1.0m.

Fourier transform infrared emission spectra of MnH and MnD

NASA Astrophysics Data System (ADS)

Gordon, Iouli E.; Appadoo, Dominique R. T.; Shayesteh, Alireza; Walker, Kaley A.; Bernath, Peter F.

2005-01-01

Fourier transform infrared emission spectra of MnH and MnD were observed in the ground X7Σ + electronic state. The vibration-rotation bands from v = 1 → 0 to v = 3 → 2 for MnH and from v = 1 → 0 to v = 4 → 3 for MnD were recorded at an instrumental resolution of 0.0085 cm -1. Spectroscopic constants were determined for each vibrational level and equilibrium constants were found from a Dunham-type fit. The equilibrium vibrational constant ( ωe) for MnH was found to be 1546.84518(65) cm -1, the equilibrium rotational constant ( Be) is 5.6856789(103) cm -1 and the eqilibrium bond distance ( re) was determined to be 1.7308601(47) Å.

Infrared Emission from Gas-Aerosol Reactions

DTIC Science & Technology

1982-09-01

Gaseous Amonia Infrared (IR) "Gas-aerosol Reactions Sulfuric Acid- amonia IR Luminescence Exothermic Reactions Octanoic Acid- amonia IR Laser Acid-base...of radiation observed from the reactions of chloro- sulfuric acid aerosol with gaseous amonia and water. Other systems which were screened including

Optical properties of Nd3+ doped barium lithium fluoroborate glasses for near-infrared (NIR) emission

NASA Astrophysics Data System (ADS)

Mariselvam, K.; Arun Kumar, R.; Suresh, K.

2018-04-01

The neodymium doped barium lithium fluoroborate (Nd3+: BLFB) glasses with the chemical composition (70-x) H3BO3 - 10 Li2CO3 - 10 BaCO3- 5 CaF2-5 ZnO - x Nd2O3 (where x = 0.05, 0.1, 0.25, 0.5, 1, 2 in wt %) have been prepared by the conventional melt quenching technique and characterised through optical absorption, near infrared emission and decay-time measurements. The x-ray diffraction studies confirm the amorphous nature of the prepared glasses. The optical absorption spectra and emission spectra were recorded in the wavelength ranges of 190-1100 nm. The optical band gap (Eg) and Urbach energy (ΔE) values were calculated from the absorption spectra. The Judd-Ofelt intensity parameters were determined from the systematic analysis of the absorption spectrum of neodymium ions in the prepared glasses. The emission spectra exhibited three prominent peaks at 874, 1057, 1331 nm corresponding to the 4F3/2 → 4I9/2, 11/2, 13/2 transitions levels respectively in the near infrared region. The emission intensity of the 4F3/2 → 4I11/2 transition increases with the increase in neodymium concentration up to 0.5 wt% and the concentration quenching mechanism was observed for 1 wt% and 2 wt% concentrations. The lifetime of the 4F3/2 level was found to decrease with increasing Nd3+ ion concentration. The nature of energy transfer process was a single exponential curve which was studied for all the glasses and analysed.

Plasmon-photon conversion to near-infrared emission from Yb(3+): (Au/Ag-nanoparticles) in tungsten-tellurite glasses.

PubMed

Rivera, V A G; Ledemi, Yannick; Pereira-da-Silva, Marcelo A; Messaddeq, Younes; Marega, Euclydes

2016-01-04

This manuscript reports on the interaction between (2)F5/2→(2)F7/2 radiative transition from Yb(3+) ions and localized surface plasmon resonance (from gold/silver nanoparticles) in a tungsten-tellurite glass. Such an interaction, similar to the down-conversion process, results in the Yb(3+) emission in the near-infrared region via resonant and non-resonant energy transfers. We associated such effects with the dynamic coupling described by the variations generated by the Hamiltonian HDC in either the oscillator strength, or the local crystal field, i.e. the line shape changes in the emission band. Here, the Yb(3+) ions emission is achieved through plasmon-photon coupling, observable as an enhancement or quenching in the luminescence spectra. Metallic nanoparticles have light-collecting capability in the visible spectrum and can accumulate almost all the photon energy on a nanoscale, which enable the excitation and emission of the Yb(3+) ions in the near-infrared region. This plasmon-photon conversion was evaluated from the cavity's quality factor (Q) and the coupling (g) between the nanoparticles and the Yb(3+) ions. We have found samples of low-quality cavities and strong coupling between the nanoparticles and the Yb(3+) ions. Our research can be extended towards the understanding of new plasmon-photon converters obtained from interactions between rare-earth ions and localized surface plasmon resonance.

Plasmon-photon conversion to near-infrared emission from Yb3+: (Au/Ag-nanoparticles) in tungsten-tellurite glasses

PubMed Central

Rivera, V. A. G.; Ledemi, Yannick; Pereira-da-Silva, Marcelo A.; Messaddeq, Younes; Marega Jr, Euclydes

2016-01-01

This manuscript reports on the interaction between 2F5/2→2F7/2 radiative transition from Yb3+ ions and localized surface plasmon resonance (from gold/silver nanoparticles) in a tungsten-tellurite glass. Such an interaction, similar to the down-conversion process, results in the Yb3+ emission in the near-infrared region via resonant and non-resonant energy transfers. We associated such effects with the dynamic coupling described by the variations generated by the Hamiltonian HDC in either the oscillator strength, or the local crystal field, i.e. the line shape changes in the emission band. Here, the Yb3+ ions emission is achieved through plasmon-photon coupling, observable as an enhancement or quenching in the luminescence spectra. Metallic nanoparticles have light-collecting capability in the visible spectrum and can accumulate almost all the photon energy on a nanoscale, which enable the excitation and emission of the Yb3+ ions in the near-infrared region. This plasmon-photon conversion was evaluated from the cavity’s quality factor (Q) and the coupling (g) between the nanoparticles and the Yb3+ ions. We have found samples of low-quality cavities and strong coupling between the nanoparticles and the Yb3+ ions. Our research can be extended towards the understanding of new plasmon-photon converters obtained from interactions between rare-earth ions and localized surface plasmon resonance. PMID:26725938

Fluorescent H2 Emission Lines from the Reflection Nebula NGC 7023 Observed with IGRINS

NASA Astrophysics Data System (ADS)

Le, Huynh Anh N.; Pak, Soojong; Kaplan, Kyle; Mace, Gregory; Lee, Sungho; Pavel, Michael; Jeong, Ueejeong; Oh, Heeyoung; Lee, Hye-In; Chun, Moo-Young; Yuk, In-Soo; Pyo, Tae-Soo; Hwang, Narae; Kim, Kang-Min; Park, Chan; Sok Oh, Jae; Yu, Young Sam; Park, Byeong-Gon; Minh, Young Chol; Jaffe, Daniel T.

2017-05-01

We have analyzed the temperature, velocity, and density of H2 gas in NGC 7023 with a high-resolution near-infrared spectrum of the northwestern filament of the reflection nebula. By observing NGC 7023 in the H and K bands at R ≃ 45,000 with the Immersion GRating INfrared Spectrograph, we detected 68 H2 emission lines within the 1″ × 15″ slit. The diagnostic ratio of 2-1 S(1)/1-0 S(1) is 0.41-0.56. In addition, the estimated ortho-to-para ratio (OPR) is 1.63-1.82, indicating that the H2 emission transitions in the observed region arise mostly from gas excited by UV fluorescence. Gradients in the temperature, velocity, and OPR within the observed area imply motion of the photodissociation region (PDR) relative to the molecular cloud. In addition, we derive the column density of H2 from the observed emission lines and compare these results with PDR models in the literature covering a range of densities and incident UV field intensities. The notable difference between PDR model predictions and the observed data, in high rotational J levels of ν = 1, is that the predicted formation temperature for newly formed H2 should be lower than that of the model predictions. To investigate the density distribution, we combine pixels in 1″ × 1″ areas and derive the density distribution at the 0.002 pc scale. The derived gradient of density suggests that NGC 7023 has a clumpy structure, including a high clump density of ˜105 cm-3 with a size smaller than ˜5 × 10-3 pc embedded in lower-density regions of 103-104 cm-3.

Influence of KMnO4 Concentrationon Infrared Emissivity of Coatings Formed on TC4 Alloys by Micro-Arc Oxidation

PubMed Central

Li, Ying; Li, Chaozhong; Hu, Dan; Li, Zhengxian; Xi, Zhengping

2017-01-01

Ceramic coatings with high emissivity were fabricated on TC4 alloys by micro-arc oxidation technique (MAO) in mixed silicate and phosphate electrolytes with varying KMnO4 addition. The microstructure, phase and chemical composition were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), and the infrared emissivity of the MAO coatings was measured in a waveband of 5–20 μm. The results show that the thickness of the coatings increased with the addition of KMnO4, but the roughness of the coatings first decreased and then increased slightly due to the inhibitory effect of KMnO4 on Na2SiO3 deposition. The main phase composition of the coatings was anatase and rutile TiO2, amorphous form of SiO2 and MnO2. The infrared emissivity value of the coatings strongly depended on KMnO4 concentration, the coating formed at the concentration of 0.8 g/L KMnO4 reached the highest and an average of up to 0.87 was observed. PMID:29137192

Extended infrared emission around IRAS 21282 + 5050

NASA Technical Reports Server (NTRS)

Bregman, Jesse D.; Booth, John; Gilmore, D. K.; Kay, Laura; Rank, David

1992-01-01

Multiaperture 3-4-micron spectra along with K- and L-band images of the compact planetary nebula IRAS 21282 + 5050 show a 5 arcsec - 20 arcsec diameter nebula with structure similar to many other planetary nebulae. The spectral observations and the L-band image show evidence for extended PAH emission out to a radius of 20 arcsec, while the K-band image shows a 5 arcsec diameter nebula. An observed linear increase of integrated brightness with aperture size at L band implies a 1/r exp 2 volume emissivity for a spherically symmetric model. The spectral similarity of the emission in the small and large apertures suggests fluorescent emission by the PAHs. If the observed emission is from PAHs which formed during the planetary nebulae stage of IRAs 21282 + 5050, then PAHs have been forming for not less than 3000 yr. If the PAH emission is from material produced during the earlier red giant phase, then the formation time frame was much longer. The morphological and spectral similarity of IRAS 21282 + 5050 to many other planetary nebulae suggests that this phenomenon may be widespread, and that planetary nebulae may be a significant source of interstellar PAHs.

Infrared surveys of Hawaiian volcanoes

USGS Publications Warehouse

Fischer, W. A.; Moxham, R.M.; Polcyn, F.; Landis, G.H.

1964-01-01

Aerial infrared-sensor surveys of Kilauea volcano have depicted the areal extent and the relative intensity of abnormal thermal features in the caldera area of the volcano and along its associated rift zones. Many of these anomalies show correlation with visible steaming and reflect convective transfer of heat to the surface from subterranean sources. Structural details of the volcano, some not evident from surface observation, are also delineated by their thermal abnormalities. Several changes were observed in the patterns of infrared emission during the period of study; two such changes show correlation in location with subsequent eruptions, but the cause-and-effect relationship is uncertain.Thermal anomalies were also observed on the southwest flank of Mauna Loa; images of other volcanoes on the island of Hawaii, and of Haleakala on the island of Maui, revealed no thermal abnormalities.Approximately 25 large springs issuing into the ocean around the periphery of Hawaii have been detected.Infrared emission varies widely with surface texture and composition, suggesting that similar observations may have value for estimating surface conditions on the moon or planets.

Near-infrared observations of the variable crab nebula

NASA Astrophysics Data System (ADS)

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

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

The inception of star cluster formation revealed by [C II] emission around an Infrared Dark Cloud

NASA Astrophysics Data System (ADS)

Bisbas, Thomas G.; Tan, Jonathan C.; Csengeri, Timea; Wu, Benjamin; Lim, Wanggi; Caselli, Paola; Güsten, Rolf; Ricken, Oliver; Riquelme, Denise

2018-07-01

We present SOFIA-upGREAT observations of [C II] emission of Infrared Dark Cloud (IRDC) G035.39-00.33, designed to trace its atomic gas envelope and thus test models of the origins of such clouds. Several velocity components of [C II] emission are detected, tracing structures that are at a wide range of distances in the Galactic plane. We find a main component that is likely associated with the IRDC and its immediate surroundings. This strongest emission component has a velocity similar to that of the 13CO(2-1) emission of the IRDC, but offset by ˜3 km s-1 and with a larger velocity width of ˜9 km s-1. The spatial distribution of the [C II] emission of this component is also offset predominantly to one side of the dense filamentary structure of the IRDC. The C II column density is estimated to be of the order of ˜1017-1018 cm-2. We compare these results to the [C II] emission from numerical simulations of magnetized, dense gas filaments formed from giant molecular cloud (GMC) collisions, finding similar spatial and kinematic offsets. These observations and modellingof [C II] add further to the evidence that IRDC G035.39-00.33 has been formed by a process of GMC-GMC collision, which may thus be an important mechanism for initiating star cluster formation.

Rapid-Response Low Infrared Emission Broadband Ultrathin Plasmonic Light Absorber

PubMed Central

Tagliabue, Giulia; Eghlidi, Hadi; Poulikakos, Dimos

2014-01-01

Plasmonic nanostructures can significantly advance broadband visible-light absorption, with absorber thicknesses in the sub-wavelength regime, much thinner than conventional broadband coatings. Such absorbers have inherently very small heat capacity, hence a very rapid response time, and high light power-to-temperature sensitivity. Additionally, their surface emissivity can be spectrally tuned to suppress infrared thermal radiation. These capabilities make plasmonic absorbers promising candidates for fast light-to-heat applications, such as radiation sensors. Here we investigate the light-to-heat conversion properties of a metal-insulator-metal broadband plasmonic absorber, fabricated as a free-standing membrane. Using a fast IR camera, we show that the transient response of the absorber has a characteristic time below 13 ms, nearly one order of magnitude lower than a similar membrane coated with a commercial black spray. Concurrently, despite the small thickness, due to the large absorption capability, the achieved absorbed light power-to-temperature sensitivity is maintained at the level of a standard black spray. Finally, we show that while black spray has emissivity similar to a black body, the plasmonic absorber features a very low infra-red emissivity of almost 0.16, demonstrating its capability as selective coating for applications with operating temperatures up to 400°C, above which the nano-structure starts to deform. PMID:25418040

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

Titan's Thermal Emission: Analysis Of Near-surface Temperatures Via Mid-infrared Measurements

NASA Astrophysics Data System (ADS)

Sadino, Jeff; Parrish, P. D.; Orton, G. S.; Burl, M. C.; Davies, A. G.; Irwin, P. G.; Teanby, N. A.; Flasar, F. M.; Cassini/CIRS investigation Team

2006-09-01

After Courtin and Kim 2002, tropospheric and near-surface temperatures of Titan may be obtained by examining mid-infrared radiances at 300 and 500 wavenumbers (33 and 20 microns). Here, the measured radiance is (respectively) sensitive to the temperature near the tropopause and sufficient to discern variations in surface topography and emissivity. Our search, as a function of location and time, compares brightness temperatures derived from measurements by the Cassini Composite Infrared Spectrometer (CIRS) and variations of radiance as a function of Titan's rotation derived from ground-based measurements at NASA's Infrared Telescope Facility. Although the variation of the tropopause and zonal near-surface temperatures are fairly homogenous, similar to Courtin and Kim 2002, the meridional distribution of near-surface temperatures varies symmetrically from Equator to pole. While no significant thermal variations suggestive of localized hotspots have yet been observed, such diversity is suggestive of active surface geology, in support of other optical and near-infrared investigations. Although the spatial coverage of the CIRS dataset is severely limited, the approximately 10 degrees field of view (450km at the Equator) is de-convolved somewhat to extract meaningful, sub-pixel maps of Titan's surface. Courtin, R. and Kim, S. (2002). Planet. and Sp. Sci., 50: 309-321. The acquisition of data described here was accomplished through the coordinated effort of Cassini-Huygens project staff, Deep Space Network personnel and the CIRS instrument and science-planning teams with funding provided by the National Research Council, NASA/JPL and NASA/GSFC and the UK Particle Physics and Astronomy council.

RESOLVING THE ACTIVE GALACTIC NUCLEUS AND HOST EMISSION IN THE MID-INFRARED USING A MODEL-INDEPENDENT SPECTRAL DECOMPOSITION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hernán-Caballero, Antonio; Alonso-Herrero, Almudena; Hatziminaoglou, Evanthia

2015-04-20

We present results on the spectral decomposition of 118 Spitzer Infrared Spectrograph (IRS) spectra from local active galactic nuclei (AGNs) using a large set of Spitzer/IRS spectra as templates. The templates are themselves IRS spectra from extreme cases where a single physical component (stellar, interstellar, or AGN) completely dominates the integrated mid-infrared emission. We show that a linear combination of one template for each physical component reproduces the observed IRS spectra of AGN hosts with unprecedented fidelity for a template fitting method with no need to model extinction separately. We use full probability distribution functions to estimate expectation values andmore » uncertainties for observables, and find that the decomposition results are robust against degeneracies. Furthermore, we compare the AGN spectra derived from the spectral decomposition with sub-arcsecond resolution nuclear photometry and spectroscopy from ground-based observations. We find that the AGN component derived from the decomposition closely matches the nuclear spectrum with a 1σ dispersion of 0.12 dex in luminosity and typical uncertainties of ∼0.19 in the spectral index and ∼0.1 in the silicate strength. We conclude that the emission from the host galaxy can be reliably removed from the IRS spectra of AGNs. This allows for unbiased studies of the AGN emission in intermediate- and high-redshift galaxies—currently inaccesible to ground-based observations—with archival Spitzer/IRS data and in the future with the Mid-InfraRed Instrument of the James Webb Space Telescope. The decomposition code and templates are available at http://denebola.org/ahc/deblendIRS.« less

Infrared sensing of non-observable human biometrics

NASA Astrophysics Data System (ADS)

Willmore, Michael R.

2005-05-01

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

Hot Spots on Io: Correlation of Infrared Emission and Visible Reflectance

NASA Technical Reports Server (NTRS)

Mcewen, A. S.; Soderblom, L.; Matson, D. L.; Johnson, T. V.

1985-01-01

The Voyager 1 infrared spectrometer (IRIS) data and two recently compiled data sets (Voyager imaging mosaics and measurements of Io's thermal emission from the NASA Infrared Telescope Facility) are correlated. These data were used to refine the correlation between dark spot optical properties (albedo and color) and thermal emission, to examine this correspondence on a satellite-wide scale, and to identify additional hot spots not included in the IRIS inventory. The results suggest the hot spots are liquid sulfur lava lakes, for the following reasons: (1) the melting point of sulfur is 390 K, and the model hot spot temperatures range from approximately 200 to 450 K; (2) the albedos and color of the dark spots, measured from the global mosaics, are consistent with laboratory measurements for liquid sulfur; (3) high resolution images of the dark features show morphologies suggestive of lava lakes; and (4) this hypothesis provides a simple and direct explanation for why dark spots are hot on Io.

ENHANCED WARM H{sub 2} EMISSION IN THE COMPACT GROUP MID-INFRARED ''GREEN VALLEY''

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cluver, M. E.; Ogle, P.; Guillard, P.

2013-03-10

We present results from a Spitzer mid-infrared spectroscopy study of a sample of 74 galaxies located in 23 Hickson Compact Groups (HCGs), chosen to be at a dynamically active stage of H I depletion. We find evidence for enhanced warm H{sub 2} emission (i.e., above that associated with UV excitation in star-forming regions) in 14 galaxies ({approx}20%), with 8 galaxies having extreme values of L(H{sub 2} S(0)-S(3))/L(7.7 {mu}m polycyclic aromatic hydrocarbon), in excess of 0.07. Such emission has been seen previously in the compact group HCG 92 (Stephan's Quintet), and was shown to be associated with the dissipation of mechanicalmore » energy associated with a large-scale shock caused when one group member collided, at high velocity, with tidal debris in the intragroup medium. Similarly, shock excitation or turbulent heating is likely responsible for the enhanced H{sub 2} emission in the compact group galaxies, since other sources of heating (UV or X-ray excitation from star formation or active galactic nuclei) are insufficient to account for the observed emission. The group galaxies fall predominantly in a region of mid-infrared color-color space identified by previous studies as being connected to rapid transformations in HCG galaxy evolution. Furthermore, the majority of H{sub 2}-enhanced galaxies lie in the optical ''green valley'' between the blue cloud and red sequence, and are primarily early-type disk systems. We suggest that H{sub 2}-enhanced systems may represent a specific phase in the evolution of galaxies in dense environments and provide new insight into mechanisms which transform galaxies onto the optical red sequence.« less

Infrared monitoring of the Space Station environment

NASA Technical Reports Server (NTRS)

Kostiuk, Theodor; Jennings, Donald E.; Mumma, Michael J.

1988-01-01

The measurement and monitoring of infrared emission in the environment of the Space Station has a twofold importance - for the study of the phenomena itself and as an aid in planning and interpreting Station based infrared experiments. Spectral measurements of the infrared component of the spacecraft glow will, along with measurements in other spectral regions, provide data necessary to fully understand and model the physical and chemical processes producing these emissions. The monitoring of the intensity of these emissions will provide background limits for Space Station based infrared experiments and permit the determination of optimum instrument placement and pointing direction. Continuous monitoring of temporal changes in the background radiation (glow) will also permit better interpretation of Station-based infrared earth sensing and astronomical observations. The primary processes producing infrared emissions in the Space Station environment are: (1) Gas phase excitations of Station generated molecules ( e.g., CO2, H2O, organics...) by collisions with the ambient flux of mainly O and N2. Molecular excitations and generation of new species by collisions of ambient molecules with Station surfaces. They provide a list of resulting species, transition energies, excitation cross sections and relevant time constants. The modeled spectrum of the excited species occurs primarily at wavelengths shorter than 8 micrometer. Emissions at longer wavelengths may become important during rocket firing or in the presence of dust.

Far-red to near infrared emission and scattering spectroscopy for biomedical applications

NASA Astrophysics Data System (ADS)

Zhang, Gang

2001-06-01

The thesis investigates the far-red and near infrared (NIR) spectral region from biomedical tissue samples for monitoring the state of tissues. The NIR emission wing intensity is weak in comparison to the emission in the visible spectral region. The wing emission from biomedical samples has revealed meaningful information about the state of the tissues. A model is presented to explain the shape of the spectral wing based on a continuum of energy levels. The wing can be used to classify different kinds of tissues; especially it can be used to differentiate cancer part from normal human breast tissues. The research work of the far-red emission from thermal damaged tissue samples shows that the emission intensity in this spectral region is proportional to the extent of the thermal damage of the tissue. Near infrared spectral absorption method is used to investigate blood hemodynamics (perfusion and oxygenation) in brain during sleep-wake transition. The result of the research demonstrates that the continuous wave (CW) type near infrared spectroscopy (NIRS) device can be used to investigate brain blood perfusion and oxygenation with a similar precision with frequency domain (FD) type device. The human subject sleep and wake transition, has been monitored by CW type NIRS instrument with traditional electroencephalograph (EEG) method. Parallel change in oxy-Hb and deoxy-Hb is a discrete event that occurs in the transition from both sleep to wakefulness and wakefulness to sleep. These hemodynamic switches are generally about few seconds delayed from the human decided transition point between sleep and wake on the polygraph EEG recording paper. The combination of NIRS and EEG methods monitor the brain activity, gives more information about the brain activity. The sleep apnea investigation was associated with recurrent apneas, insufficient nasal continuous positive airway pressure (CPAP) and the different response of the peripheral and central compartments to breathing

Phenomenological model for infrared emissions from high-explosive detonation fireballs

NASA Astrophysics Data System (ADS)

Gross, Kevin C.

Prior to this work, a phenomenological description of mid-wave infrared (MWIR) emissions from high-explosive (HE) detonation fireballs did not exist, hampering efforts to classify the type and size of HEs from their electro-optical signatures. In recent field tests, temporally-resolved infrared spectra (0.05 ≤ Delta t ≤ 0.12 s, 2 ≤ Deltanu ≤ 8 cm -1) were collected via a Fourier-transform spectrometer (FTS) from the detonation fireballs of two types of conventional military munitions (CMM) as well as uncased TNT and four types of enhanced novel explosives (ENEs). The FTS data is not appreciably corrupted by artifacts due to scene changes resulting from the fast transient events. The CMM spectra are dominated by continuum emission, and a single-temperature Planckian distribution, modified for atmospheric attenuation, captures most of the variation in the data. Fitted CMM temperatures are well described by an exponential decay to ambient at an approximate rate of 0.8 s-1. A two-temperature fit to CMM spectra improved results, suggesting variations in the temperature field are important. Some evidence of selective emission is identified by systematic patterns in the fit residuals. The behavior of these systematic residuals affords a distinction between the two types of CMMs studied. The uncased TNT and ENE spectra appear strongly influenced by both continuum and selective emission. For the purpose of dimensionality reduction, a physics-based spectral model is developed consisting of seven parameters---fireball size, temperature, particulate absorption coefficient, and gas concentrations for H2O, CO2, CO, and HCl. Fitting this model to the observed MWIR spectra affords a compact, high-fidelity representation with physically-constrained features that correlate with both the type and weight of the HE. For example, the hydrogen-to-carbon ratio (R) estimated from the fitted concentrations separates the TNT and ENE events. Spectrally-determined R values are somewhat

Time-resolved infrared spectrophotometric observations of high area to mass ratio (HAMR) objects in GEO

NASA Astrophysics Data System (ADS)

Skinner, Mark A.; Russell, Ray W.; Rudy, Richard J.; Gutierrez, David J.; Kim, Daryl L.; Crawford, Kirk; Gregory, Steve; Kelecy, Tom

2011-12-01

Optical surveys have identified a class of high area-to-mass ratio (HAMR) objects in the vicinity of the Geostationary Earth Orbit (GEO) ring [1]. The exact origin and nature of these objects are not well known, although their proximity to the GEO ring poses a hazard to active GEO satellites. Due to their high area-to-mass ratios, solar radiation pressure perturbs their orbits in ways that makes it difficult to predict their orbital trajectories over periods of time exceeding a week. To better understand these objects and their origins, observations that allow us to derive physical characteristics are required in order to improve the non-conservative force modeling for orbit determination and prediction. Information on their temperatures, areas, emissivities, and albedos may be obtained from thermal infrared, mid-wave infrared (MWIR), and visible measurements. Spectral features may help to identify the composition of the material, and thus possible origins for these objects. We have collected observational data on various HAMR objects from the AMOS observatory 3.6 m AEOS telescope. The thermal-IR spectra of these low-earth orbit objects acquired by the Broadband Array Spectrograph System (BASS) span wavelengths 3-13 μm and constitute a unique data set, providing a means of measuring, as a function of time, object fluxes. These, in turn, allow temperatures and emissivity-area products to be calculated. In some instances we have also collected simultaneous filtered visible photometric data on the observed objects. The multi-wavelength observations of the objects provide possible clues as to the nature of the observed objects. We describe briefly the nature and status of the instrumental programs used to acquire the data, our data of record, our data analysis techniques, and our current results, as well as future plans.

Correlations between Venus nightside near infrared emissions measured by VIRTIS/Venus Express and Magellan radar data

NASA Astrophysics Data System (ADS)

Mueller, N.; Helbert, J.; Hashimoto, G. L.; Tsang, C. C. C.; Erard, S.; Piccioni, G.; Drossart, P.

2008-09-01

Background The Venus Express Spacecraft images the nightside thermal emissions using the VIRTIS imaging spectrometer. At 1.02 micron thermal emission from the surface is penetrates the atmosphere but the signal is attenuated by scattering and absorption [1, 2]. Although the measured flux at top of the atmosphere is nonlinearly related to the original emission of the surface, it is still positively correlated with the product of surface temperature and surface emissivity [3]. The surface temperature of Venus is relatively well constrained as a monotonous function of altitude. Emissivity at 1 micron depends strongly on surface composition, in particular abundance of mafic minerals [3]. Mapping the thermal emission of the surface of Venus therefore supplements radar data as it allows to infer relative variation of surface composition. Data Processing This study examines the correlation of VIRTIS images showing a signal of the surface with all known parameters that govern radiance and applies semi empirical relations to remove the respective influences. 1. Stray sunlight is removed by subtraction of a spectrum template scaled to fit radiance at 1.4 ¹m [2] 2. Limb darkening is accounted for using a linear phase function consistent with results of radiative transfer modeling [4]. 3. Cloud opacity is determined from 1.31 ¹m and applied to 1.02 ¹m while accounting for multiple reflections between lower atmosphere and clouds [3]. Result is brightness temperature of thermal emission below the cloud deck but above the lowest 20 km of the atmosphere. 4. Influence of surface temperature and lower atmosphere absorption is determined by correlation of VIRTIS declouded brightness temperature and Magellan Topography data [5]. To further reduce the influence of cloud contrast and increase the signal of the surface, all suitable VIRTIS observations are map projected and stacked to create a map of the southern hemisphere of Venus. Observations and Interpretation As expected from

Investigating the 3.3 micron infrared fluorescence from naphthalene following ultraviolet excitation

NASA Technical Reports Server (NTRS)

Williams, Richard M.; Leone, Stephen R.

1994-01-01

Polycyclic aromatic hydrocarbon (PAH) type molecules are proposed as the carriers of the unidentified infrared (UIR) bands. Detailed studies of the 3.3 micrometer infrared emission features from naphthalene, the simplest PAH, following ultraviolet laser excitation are used in the interpretation of the 3.29 micrometer (3040 cm(sup -1)) UIR band. A time-resolved Fourier transform spectrometer is used to record the infrared emission spectrum of gas-phase naphthalene subsequent to ultraviolet excitation facilitated by an excimer laser operated at either 193 nm or 248 nm. The emission spectra differ significantly from the absorption spectrum in the same spectral region. Following 193 nm excitation the maximum in the emission profile is red-shifted 45 cm(sup -1) relative to the absorption maximum; a 25 cm(sup -1) red-shift is observed after 248 nm excitation. The red-shifting of the emission spectrum is reduced as collisional and radiative relaxation removes energy from the highly vibrationally excited molecules. Coupling between the various vibrational modes is thought to account for the differences between absorption and emission spectra. Strong visible emission is also observed following ultraviolet excitation. Visible emission may play an important role in the rate of radiative relaxation, which according to the interstellar PAH hypothesis occurs only by the slow emission of infrared photons. Studying the visible emission properties of PAH type molecules may be useful in the interpretation of the DIB's observed in absorption.

Fluorescent H{sub 2} Emission Lines from the Reflection Nebula NGC 7023 Observed with IGRINS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le, Huynh Anh N.; Pak, Soojong; Lee, Hye-In

We have analyzed the temperature, velocity, and density of H{sub 2} gas in NGC 7023 with a high-resolution near-infrared spectrum of the northwestern filament of the reflection nebula. By observing NGC 7023 in the H and K bands at R ≃ 45,000 with the Immersion GRating INfrared Spectrograph, we detected 68 H{sub 2} emission lines within the 1″ × 15″ slit. The diagnostic ratio of 2-1 S(1)/1-0 S(1) is 0.41−0.56. In addition, the estimated ortho-to-para ratio (OPR) is 1.63−1.82, indicating that the H{sub 2} emission transitions in the observed region arise mostly from gas excited by UV fluorescence. Gradients inmore » the temperature, velocity, and OPR within the observed area imply motion of the photodissociation region (PDR) relative to the molecular cloud. In addition, we derive the column density of H{sub 2} from the observed emission lines and compare these results with PDR models in the literature covering a range of densities and incident UV field intensities. The notable difference between PDR model predictions and the observed data, in high rotational J levels of ν = 1, is that the predicted formation temperature for newly formed H{sub 2} should be lower than that of the model predictions. To investigate the density distribution, we combine pixels in 1″ × 1″ areas and derive the density distribution at the 0.002 pc scale. The derived gradient of density suggests that NGC 7023 has a clumpy structure, including a high clump density of ∼10{sup 5} cm{sup −3} with a size smaller than ∼5 × 10{sup −3} pc embedded in lower-density regions of 10{sup 3}–10{sup 4} cm{sup −3}.« less

Hydrothermal synthesis and infrared emissivity property of flower-like SnO{sub 2} particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, J. X.; Beijing Institute of Environmental Features, Beijing, 100854; Zhang, Z. Y., E-mail: zhangzy@nwu.edu.cn

The flower-like SnO{sub 2} particles are synthesized through a simple hydrothermal process. The microstructure, morphology and the infrared emissivity property of the as-prepared products are characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and infrared spectroradio meter (ISM) respectively. The results show that the as-prepared SnO{sub 2} products are all indexed to tetragonal cassiterite phase of SnO{sub 2}. The different molarity ratios of the OH{sup −} concentration to Sn{sup 4+} concentration ([OH{sup −}]:[Sn{sup 4+}]) and the polyacrylamide (PAM) lead to the different morphological structures of SnO{sub 2}, which indicates that both the [OH{sup −}]:[Sn{sup 4+}]more » and the PAM play an important role in the morphological evolution respectively. The infrared emissivities of the as-prepared SnO{sub 2} products are discussed.« less

VLBI observations of Infrared-Faint Radio Sources

NASA Astrophysics Data System (ADS)

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

2006-10-01

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

Enhanced infra-red emission from sub-millimeter microelectromechanical systems micro hotplates via inkjet deposited carbon nanoparticles and fullerenes

NASA Astrophysics Data System (ADS)

De Luca, A.; Cole, M. T.; Fasoli, A.; Ali, S. Z.; Udrea, F.; Milne, W. I.

2013-06-01

In this paper, we demonstrate a micro-inkjet printing technique as a reproducible post-process for the deposition of carbon nanoparticles and fullerene adlayers onto fully CMOS compatible micro-electro-mechanical silicon-on-insulator infrared (IR) light sources to enhance their infrared emission. We show experimentally a significant increase in the infrared emission efficiency of the coated emitters. We numerically validate these findings with models suggesting a dominant performance increase for wavelengths <5.5 μm. Here, the bimodal size distribution in the diameter of the carbon nanoparticles, relative to the fullerenes, is an effective mediator towards topologically enhanced emittance of our miniaturised emitters. A 90% improvement in IR emission power density has been shown which we have rationalised with an increase in the mean thickness of the deposited carbon nanoparticle adlayer.

Luminescence studies and infrared emission of erbium-doped calcium zirconate phosphor.

PubMed

Tiwari, Neha; Dubey, Vikas

2016-05-01

The near-infrared-to-visible upconversion luminescence behaviour of Er(3+)-doped CaZrO3 phosphor is discussed in this manuscript. The phosphor was prepared by a combustion synthesis technique that is suitable for less-time-taking techniques for nanophosphors. The starting materials used for sample preparation were Ca(NO3)2.4H2O, Zr(NO3)4 and Er(NO3)2, and urea was used as a fuel. The prepared sample was characterized by X-ray diffraction (XRD). The surface morphology of prepared phosphor was determined by field emission gun scanning electron microscopy (FEGSEM). The functional group analysis was determined by Fourier transform infrared (FTIR) spectroscopy. All prepared phosphors with variable Er(3+) concentrations (0.5-2.5 mol%) were studied by photoluminescence analysis. It was found that the excitation spectra of the prepared phosphor showed a sharp excitation peak centred at 980 nm. The emission spectra with variable Er(3+) concentrations showed strong peaks in the 555 nm and 567 nm range, with a dominant peak at 555 nm due to the ((2)H(11/2),(4)S(3/2)) transition and a weaker transition at 567 nm associated with 527 nm. Spectrophotometric determination of the peak was evaluated by the Commission Internationale de I'Eclairage (CIE) method These upconverted emissions were attributed to a two-photon process. The excitation wavelength dependence of the upconverted luminescence, together with its time evolution after infrared pulsed excitation, suggested that energy transfer upconversion processes were responsible for the upconversion luminescence. The upconversion mechanisms were studied in detail through laser power dependence. Excited state absorption and energy transfer processes were discussed as possible upconversion mechanisms. The cross-relaxation process in Er(3+) was also investigated. Copyright © 2015 John Wiley & Sons, Ltd.

First Detection of Near-infrared Line Emission from Organics in Young Circumstellar Disks

NASA Astrophysics Data System (ADS)

Mandell, Avi M.; Bast, Jeanette; van Dishoeck, Ewine F.; Blake, Geoffrey A.; Salyk, Colette; Mumma, Michael J.; Villanueva, Geronimo

2012-03-01

We present an analysis of high-resolution spectroscopy of several bright T Tauri stars using the CRIRES spectrograph on the Very Large Telescope and NIRSPEC spectrograph on the Keck Telescope, revealing the first detections of emission from HCN and C2H2 in circumstellar disks at near-infrared wavelengths. Using advanced data reduction techniques, we achieve a dynamic range with respect to the disk continuum of ~500 at 3 μm, revealing multiple emission features of H2O, OH, HCN, and C2H2. We also present stringent upper limits for two other molecules thought to be abundant in the inner disk, CH4 and NH3. Line profiles for the different detected molecules are broad but centrally peaked in most cases, even for disks with previously determined inclinations of greater than 20°, suggesting that the emission has both a Keplerian and non-Keplerian component as observed previously for CO emission. We apply two different modeling strategies to constrain the molecular abundances and temperatures: we use a simplified single-temperature local thermal equilibrium (LTE) slab model with a Gaussian line profile to make line identifications and determine a best-fit temperature and initial abundance ratios, and we compare these values with constraints derived from a detailed disk radiative transfer model assuming LTE excitation but utilizing a realistic temperature and density structure. Abundance ratios from both sets of models are consistent with each other and consistent with expected values from theoretical chemical models, and analysis of the line shapes suggests that the molecular emission originates from within a narrow region in the inner disk (R < 1 AU). Based partially on observations collected at the European Southern Observatory Very Large Telescope under program ID 179.C-0151, program ID 283.C-5016, and program ID 082.C-0432 (P.I.: Pontopiddan).

High-efficiency electroluminescence and amplified spontaneous emission from a thermally activated delayed fluorescent near-infrared emitter

NASA Astrophysics Data System (ADS)

Kim, Dae-Hyeon; D'Aléo, Anthony; Chen, Xian-Kai; Sandanayaka, Atula D. S.; Yao, Dandan; Zhao, Li; Komino, Takeshi; Zaborova, Elena; Canard, Gabriel; Tsuchiya, Youichi; Choi, Eunyoung; Wu, Jeong Weon; Fages, Frédéric; Brédas, Jean-Luc; Ribierre, Jean-Charles; Adachi, Chihaya

2018-02-01

Near-infrared organic light-emitting diodes and semiconductor lasers could benefit a variety of applications including night-vision displays, sensors and information-secured displays. Organic dyes can generate electroluminescence efficiently at visible wavelengths, but organic light-emitting diodes are still underperforming in the near-infrared region. Here, we report thermally activated delayed fluorescent organic light-emitting diodes that operate at near-infrared wavelengths with a maximum external quantum efficiency of nearly 10% using a boron difluoride curcuminoid derivative. As well as an effective upconversion from triplet to singlet excited states due to the non-adiabatic coupling effect, this donor-acceptor-donor compound also exhibits efficient amplified spontaneous emission. By controlling the polarity of the active medium, the maximum emission wavelength of the electroluminescence spectrum can be tuned from 700 to 780 nm. This study represents an important advance in near-infrared organic light-emitting diodes and the design of alternative molecular architectures for photonic applications based on thermally activated delayed fluorescence.

A method for combining passive microwave and infrared rainfall observations

NASA Technical Reports Server (NTRS)

Kummerow, Christian; Giglio, Louis

1995-01-01

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

Method And Apparatus For Examining A Tissue Using The Spectral Wing Emission Therefrom Induced By Visible To Infrared Photoexcitation.

DOEpatents

Alfano, Robert R.; Demos, Stavros G.; Zhang, Gang

2003-12-16

Method and an apparatus for examining a tissue using the spectral wing emission therefrom induced by visible to infrared photoexcitation. In one aspect, the method is used to characterize the condition of a tissue sample and comprises the steps of (a) photoexciting the tissue sample with substantially monochromatic light having a wavelength of at least 600 nm; and (b) using the resultant far red and near infrared spectral wing emission (SW) emitted from the tissue sample to characterize the condition of the tissue sample. In one embodiment, the substantially monochromatic photoexciting light is a continuous beam of light, and the resultant steady-state far red and near infrared SW emission from the tissue sample is used to characterize the condition of the tissue sample. In another embodiment, the substantially monochromatic photoexciting light is a light pulse, and the resultant time-resolved far red and near infrared SW emission emitted from the tissue sample is used to characterize the condition of the tissue sample. In still another embodiment, the substantially monochromatic photoexciting light is a polarized light pulse, and the parallel and perpendicular components of the resultant polarized time-resolved SW emission emitted from the tissue sample are used to characterize the condition of the tissue sample.

First laboratory high-temperature emissivity measurements of Venus analog measurements in the near-infrared atmospheric windows

NASA Astrophysics Data System (ADS)

Helbert, J.; Maturilli, A.; Ferrari, S.; Dyar, M. D.; Smrekar, S. E.

2014-12-01

The permanent cloud cover of Venus prohibits observation of the surface with traditional imaging techniques over most of the visible spectral range. Venus' CO2 atmosphere is transparent exclusively in small spectral windows near 1 μm. The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) team on the European Space Agency Venus-Express mission have recently used these windows successfully to map the southern hemisphere from orbit. VIRTIS is showing variations in surface brightness, which can be interpreted as variations in surface emissivity. Deriving surface composition from these variations is a challenging task. Comparison with laboratory analogue spectra are complicated by the fact that Venus has an average surface temperature of 730K. Mineral crystal structures and their resultant spectral signatures are notably affected by temperature, therefore any interpretations based on room temperature laboratory spectra database can be misleading. In order to support the interpretation of near-infrared data from Venus we have started an extensive measurement campaign at the Planetary Emissivity Laboratory (PEL, Institute of Planetary Research of the German Aerospace Center, Berlin). The PEL facility, which is unique in the world, allows emission measurements covering the 1 to 2 μm wavelength range at sample temperatures of up to 770K. Conciliating the expected emissivity variation between felsic and mafic minerals with Venera and VEGA geochemical data we have started with a set of five analog samples. This set includes basalt, gneiss, granodiorite, anorthosite and hematite, thus covering the range of mineralogies. Preliminary results show significant spectral contrast, thus allowing different samples to be distinguished with only 5 spectral points and validating the use of thermal emissivity for investigating composition. This unique new dataset from PEL not only allows interpretation of the Venus Express VIRTIS data but also provide a baseline for considering

Spectral emissivity and transmissivity measurement for zinc sulphide infrared window based on integrating-sphere reflectometry

NASA Astrophysics Data System (ADS)

Zhang, Yu-Feng; Dai, Jing-Min; Zhang, Lei; Pan, Wei-Dong

2013-08-01

The spectral emissivity and transmissivity of zinc sulphide (ZnS) infrared windows in the spectral region from 2 to 12 μm and temperature range from 20 to 700°C is measured by a facility built at the Harbin Institute of Technology (HIT). The facility is based on the integrating-sphere reflectometry. Measurements have been performed on two samples made of ZnS. The results measured at 20°C are in good agreement with those obtained by the method of radiant energy comparison using a Fourier transform infrared spectrometer. Emissivity measurements performed with this facility present an uncertainty of 5.5% (cover factor=2).

Preparation and characterization of Chitosan/Konjac glucomannan/CdS nanocomposite film with low infrared emissivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Feng-Ying; Zhou, Yu-Ming, E-mail: fchem@seu.edu.cn; Sun, Yan-qing

Novel organic-inorganic nanocomposite films were prepared with Chitosan (CS), Konjac glucomannan (KGM) and CdS by one-step synthesis. As-prepared films were characterized by IR spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and infrared emissometer (IR). The results indicated that grown CdS dendrites were formed with reaction time of 12 h for Cd{sup 2+} and CS/KGM, and were well dispersed in CS/KGM with an average diameter of 40 nm. The CS/KGM/CdS nanocomposite films had significantly low infrared emissivity. When the mole ratio of CdS to summation of CS and KGM construction units was 1.0 with CdS size of 10-20 nm,more » the film got the lowest infrared emissivity value of 0.011, which could be attributed to the strong synergism effect existing between CS/KGM and CdS dendrites.« less

Airborne observations of the Orion molecular hydrogen emission spectrum

NASA Technical Reports Server (NTRS)

Davis, D. S.; Larson, H. P.; Smith, H. A.

1982-01-01

The Orion near-infrared H2 emission spectrum was observed from an altitude of 12.5 km in order to measure line intensities free from interference by terrestrial H2O. For the peak source, the observations indicate that the differential extinction between 4126 and 4712 per cm is 0.59 + or -0.06 mag, and the relative line intensities are consistent with those expected from a homogeneous source in approximate LTE at 1540 + or -100 K. An anomalous ortho/para H2 abundance ratio of 3.5(+ or - 0.2):1 is found, and the estimated total luminosity in vibrationally excited H2 lines is 300 + or - 100 solar luminosities. Rough molecular abundance limits, based on the missing H2 Q(6) line and the good agreement between other line intensities and the LTE model, place the H2 region no deeper within OMC-1 than the IR cluster and no shallower than 50 percent of the depth to the cluster.

Infrared sensors for Earth observation missions

NASA Astrophysics Data System (ADS)

Ashcroft, P.; Thorne, P.; Weller, H.; Baker, I.

2007-10-01

SELEX S&AS is developing a family of infrared sensors for earth observation missions. The spectral bands cover shortwave infrared (SWIR) channels from around 1μm to long-wave infrared (LWIR) channels up to 15μm. Our mercury cadmium telluride (MCT) technology has enabled a sensor array design that can satisfy the requirements of all of the SWIR and medium-wave infrared (MWIR) bands with near-identical arrays. This is made possible by the combination of a set of existing technologies that together enable a high degree of flexibility in the pixel geometry, sensitivity, and photocurrent integration capacity. The solution employs a photodiode array under the control of a readout integrated circuit (ROIC). The ROIC allows flexible geometries and in-pixel redundancy to maximise operability and reliability, by combining the photocurrent from a number of photodiodes into a single pixel. Defective or inoperable diodes (or "sub-pixels") can be deselected with tolerable impact on the overall pixel performance. The arrays will be fabricated using the "loophole" process in MCT grown by liquid-phase epitaxy (LPE). These arrays are inherently robust, offer high quantum efficiencies and have been used in previous space programs. The use of loophole arrays also offers access to SELEX's avalanche photodiode (APD) technology, allowing low-noise, highly uniform gain at the pixel level where photon flux is very low.

Effect of surface oxidation on emissivity properties of pure aluminum in the near infrared region

NASA Astrophysics Data System (ADS)

Zhang, Kaihua; Yu, Kun; Liu, Yufang; Zhao, Yuejin

2017-08-01

Emissivity is a basic thermo physical property of materials and determines the precision of radiation thermometry. The aim of this paper is to study the effect of surface oxidation on the infrared emissivity properties of pure aluminum. The emissivity data presented in this study covers the spectral range between 0.8 and 2.2 µm and temperatures from 473 to 873 K. The samples with different oxidation time were prepared under a controlled environment. The morphology and composition of the samples were characterized by metallographic microscope and XRD techniques before and after oxidation. The thickness of oxide film with different oxidation time was accurately measured by spectroscopic ellipsometer and a parabolic growth was found. In addition, the interference model of an oxidized metal substrate is established to explain the influence of the oxide film thickness on the emissivity. The thickness of oxide film when the interference effect occurs was calculated according to the interference model. The data shows that the maximum value measured was less than the thickness value at the first order constructive interference. Neither peaks nor valleys were observed in emissivity measurements with different oxidation time at 873 K, which could be related to the thin oxide film on sample surface.

Resolving shocked and UV excited components of H2 emission in planetary nebulae with high-resolution near-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Kaplan, Kyle; Dinerstein, Harriet L.; Jaffe, Daniel Thomas

2016-06-01

Planetary nebulae (PNe) form when low and intermediate-mass stars eject their outer layers into the ISM at the end of the AGB phase. Many PNe exhibit near-infrared (NIR) emission from molecular hydrogen (H2). This NIR emission arises from radiative decay out of excited rotation-vibration (rovibrational) states. The rovibrational states can be populated by excitation to higher electronic states through absorption of a far-UV photon followed by a radiative cascade to the electronic ground state, or by collisions (e.g., in a hot gas). The two processes populate the rovibrational levels of H2 differently, so the observed emergent emission spectrum provides an effective probe of the mechanisms that excite the H2. Many PNe display line intensity ratios that are intermediate between these two processes (Otsuka et al. 2013). With the advantages of the high spectral resolution (R~40000), broad wavelength coverage (1.45-2.45 μm), and high spatial resolution of the Immersion GRating Infrared Spectrometer (IGRINS, Park et al. 2014), we are able to differentiate components in position-velocity space: we see a slowly expanding UV-excited H2 shell in the PN M 1-11 and two faster moving “bullets” of thermalized H2 that we interpret as shocked gas from a bipolar outflow. We also present observations of several other PNe that exhibit similar morphologies of thermalized and UV-excited H2 components.

Spitzer Infrared Spectrograph Observations of the Galactic Center: Quantifying the Extreme Ultraviolet/Soft X-ray Fluxes

NASA Astrophysics Data System (ADS)

Simpson, Janet P.

2018-04-01

It has long been shown that the extreme ultraviolet spectrum of the ionizing stars of H II regions can be estimated by comparing the observed line emission to detailed models. In the Galactic Center (GC), however, previous observations have shown that the ionizing spectral energy distribution (SED) of the local photon field is strange, producing both very low excitation ionized gas (indicative of ionization by late O stars) and also widespread diffuse emission from atoms too highly ionized to be found in normal H II regions. This paper describes the analysis of all GC spectra taken by Spitzer's Infrared Spectrograph and downloaded from the Spitzer Heritage Archive. In it, H II region densities and abundances are described, and serendipitously discovered candidate planetary nebulae, compact shocks, and candidate young stellar objects are tabulated. Models were computed with Cloudy, using SEDs from Starburst99 plus additional X-rays, and compared to the observed mid-infrared forbidden and recombination lines. The ages inferred from the model fits do not agree with recent proposed star formation sequences (star formation in the GC occurring along streams of gas with density enhancements caused by close encounters with the black hole, Sgr A*), with Sgr B1, Sgr C, and the Arches Cluster being all about the same age, around 4.5 Myr old, with similar X-ray requirements. The fits for the Quintuplet Cluster appear to give a younger age, but that could be caused by higher-energy photons from shocks from stellar winds or from a supernova.

Infrared Surveys of Hawaiian Volcanoes: Aerial surveys with infrared imaging radiometer depict volcanic thermal patterns and structural features.

PubMed

Fisher, W A; Moxham, R M; Polcyn, F; Landis, G H

1964-11-06

Aerial infrared-sensor surveys of Kilauea volcano have depicted the areal extent and the relative intensity of abnormal thermal features in the caldera area of the volcano and along its associated rift zones. Many of these anomalies show correlation with visible steaming and reflect convective transfer of heat to the surface from subterranean sources. Structural details of the volcano, some not evident from surface observation, are also delineated by their thermal abnormalities. Several changes were observed in the patterns of infrared emission during the period of study; two such changes show correlation in location with subsequent eruptions, but the cause-and-effect relationship is uncertain. Thermal anomalies were also observed on the southwest flank of Mauna Loa; images of other volcanoes on the island of Hawaii, and of Haleakala on the island of Maui, revealed no thermal abnormalities. Approximately 25 large springs issuing into the ocean around the periphery of Hawaii have been detected. Infrared emission varies widely with surface texture and composition, suggesting that similar observations may have value for estimating surface conditions on the moon or planets.

QUANTIFYING THE HEATING SOURCES FOR MID-INFRARED DUST EMISSIONS IN GALAXIES: THE CASE OF M 81

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, N.; Zhao, Y.; Bendo, G. J.

2014-12-20

With the newly available photometric images at 250 and 500 μm from the Herschel Space Observatory, we study quantitative correlations over a sub-kiloparsec scale among three distinct emission components in the interstellar medium of the nearby spiral galaxy M 81 (NGC 3031): (1) I {sub 8} or I {sub 24}, the surface brightness of the mid-infrared emission observed in the Spitzer Space Telescope 8 or 24 μm band, with I {sub 8} and I {sub 24} being dominated by the emissions from polycyclic aromatic hydrocarbons (PAHs) and very small grains (VSGs) of dust, respectively; (2) I {sub 500}, that of the coldmore » dust continuum emission in the Herschel Space Observatory 500 μm band, dominated by the emission from large dust grains heated by evolved stars; and (3) I {sub Hα}, a nominal surface brightness of the Hα line emission, from gas ionized by newly formed massive stars. The results from our correlation study, free from any assumption on or modeling of dust emissivity law or dust temperatures, present solid evidence for significant heating of PAHs and VSGs by evolved stars. In the case of M 81, about 67% (48%) of the 8 μm (24 μm ) emission derives its heating from evolved stars, with the remainder attributed to radiation heating associated with ionizing stars.« less

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.

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.

Analysis of SO II point source emissions using NASA atmospheric infrared sounder data

NASA Astrophysics Data System (ADS)

Shen, Sylvia S.; Miller, David P.; Lewis, Paul E.

2007-04-01

Determining the extent to which large power plant emission sources interacting with atmospheric constituents affect the environment could play a significant role in future U.S. energy production policy. The effects on the environment caused by the interaction between power plant emissions and atmospheric constituents has not been investigated in depth due to the lack of calibrated spectral data on a suitable temporal and spatial scale. The availability of NASA's space-based Atmospheric Infrared Sounder (AIRS) data makes it possible to explore, and begin the first steps toward establishing, a correlation between known emission sources and environmental indicators. An exploratory study was conducted in which a time series of 26 cloud-free AIRS data containing two coal-fired power plants in northern New Mexico were selected, acquired, and analyzed for SO II emissions. A generic forward modeling process was also developed to derive an estimate of the expected AIRS pixel radiance containing the SO II emissions from the two power plants based on published combustion analysis data for coal and available power plant documentation. Analysis of the AIRS NEΔR calculated in this study and subsequent comparison with the radiance values for SO II calculated from the forward model provided essential information regarding the suitability and risk in the use of a modified AIRS configuration for monitoring anthropogenic point source emissions. The results of this study along with its conclusions and recommendations in conjunction with additional research collaboration in several specific topics will provide guidance for the development of the next generation infrared spectrometer system that NASA is considering building for environmental monitoring.

Searching for H2 emission from protoplanetary disks using near- and mid-infrared high-resolution spectroscopy

NASA Astrophysics Data System (ADS)

Carmona, A.; van den Ancker, M. E.; Henning, Th.; Pavlyuchenkov, Ya.; Dullemond, C. P.; Goto, M.; Fedele, D.; Stecklum, B.; Thi, W.-F.; Bouwman, J.; Waters, L. B. F. M.

2008-05-01

The mass and dynamics of protoplanetary disks are dominated by molecular hydrogen (H2). However, observationally very little is known about the H2. In this paper, we discuss two projects aimed to constrain the properties of H2 in the disk's planet forming region (R<50AU). First, we present a sensitive survey for pure-rotational H2 emission at 12.278 and 17.035 μm in a sample of nearby Herbig Ae/Be and T Tauri stars using VISIR, ESO's VLT high-resolution mid-infrared spectrograph. Second, we report on a search for H2 ro-vibrational emission at 2.1228, 2.2233 and 2.2477 μm in the classical T Tauri star LkHα 264 and the debris disk 49 Cet employing CRIRES, ESO's VLT high-resolution near-infrared spectrograph. VISIR project: none of the sources show H2 mid-IR emission. The observed disks contain less than a few tenths of MJupiter of optically thin H2 at 150 K, and less than a few MEarth at T>300 K. % and higher T. Our non-detections are consistent with the low flux levels expected from the small amount of H2 gas in the surface layer of a Chiang and Goldreich (1997) Herbig Ae two-layer disk model. In our sources the H2 and dust in the surface layer have not significantly departed from thermal coupling (Tgas/Tdust<2) and the gas-to-dust ratio in the surface layer is very likely <1000. CRIRES project: The H2 lines at 2.1218 μm and 2.2233 μm are detected in LkHα 264. An upper limit on the 2.2477 μm H2 line flux in LkHα 264 is derived. 49 Cet does not exhibit H2 emission in any of observed lines. There are a few MMoon of optically thin hot H2 in the inner disk (0.1 AU) of LkHα 264, and less than a tenth of a MMoon of hot H2 in the inner disk of 49 Cet. The shape of the 1 0 S(0) line indicates that LkHα disk is close to face-on (i<35o). The measured 1 0 S(0)/1 0 S(1) and 2 1 S(1)/1 0 S(1) line ratios in LkHα 264 indicate that the H2 is thermally excited at T<1500 K. The lack of H2 emission in the NIR spectra of 49 Cet and the absence of Hα emission suggest that

Seyfert Galaxies in the Infrared

NASA Astrophysics Data System (ADS)

Ruiz-Nishiky, Milagros

1997-10-01

This thesis contains complementary aspects of the Seyfert phenomenon, each of which is analysed to bring a better understanding of present unification theories. Observations of the nuclear regions of various types of Seyfert galaxies were mostly made at infrared wavelengths which allow the study of dusty environments and provide new information on the physical conditions of these objects. For example, near infrared spectroscopy of Seyfert 2 galaxies revealed that there is a subclass of type 2 Seyferts with hot IR excess at ~3μm with broad IR emission lines suggesting that some Seyfert 2s do in fact contain a hidden Seyfert 1 nucleus. Additional spectropolarimetry showed that the scattering screens, postulated in the standard model, are not always present in Seyfert 2s. At mid infrared wavelengths, it was found that the 10 μm nuclear emission of Seyferts with broad emission lines is intrinsically brighter than that of Seyferts with no broad lines. The extended 10μm emission shows that Seyfert 2 galaxies present enhanced star-formation when compared to Seyfert 1s. Both results pose obstacles for present unification ideas and I discuss possible interpretations to these observations. Seyfert galaxies were also observed at radio wavelengths to study their large scale emission of 1-0 CO. Surprisingly, this emission usually related with star formation activity was found to be similar in both types of Seyfert galaxies and therefore does not explain why Seyfert 2 galaxies have enhanced star formation as concluded in the 10μm study. A study of galaxy morphology and companions in this set of Seyferts shows at a significant statistical level that Seyfert 2s present a higher incidence of asymmetric morphologies compared to Seyfert 1s and field galaxies, and therefore are undergoing gravitational perturbations which may induce star formation. Near infrared spectroscopy of a large sample of Seyfert galaxies is analysed to study the excitation mechanisms of (FeII) and H2 lines

First Results from Faint Infrared Grism Survey (Figs): First Simultaneous Detection of Ly Alpha Emission and Lyman Break From a Galaxy at Z =7.51

NASA Technical Reports Server (NTRS)

Tilvi, V.; Pirzkal, N.; Malhotra, S.; Finkelstein, S. L.; Rhoads, J. E.; Windhorst, R.; Grogin, N. A.; Koekemoer, A.; Zakamska, N. L.; Ryan, R.;

First light observations with TIFR Near Infrared Imaging Camera (TIRCAM-II)

NASA Astrophysics Data System (ADS)

Ojha, D. K.; Ghosh, S. K.; D'Costa, S. L. A.; Naik, M. B.; Sandimani, P. R.; Poojary, S. S.; Bhagat, S. B.; Jadhav, R. B.; Meshram, G. S.; Bakalkar, C. B.; Ramaprakash, A. N.; Mohan, V.; Joshi, J.

TIFR near infrared imaging camera (TIRCAM-II) is based on the Aladdin III Quadrant InSb focal plane array (512×512 pixels; 27.6 μm pixel size; sensitive between 1 - 5.5 μm). TIRCAM-II had its first engineering run with the 2 m IUCAA telescope at Girawali during February - March 2011. The first light observations with TIRCAM-II were quite successful. Several infrared standard with TIRCAM-II were quite successful. Several infrared standard stars, the Trapezium Cluster in Orion region, McNeil's nebula, etc., were observed in the J, K and in a narrow-band at 3.6 μm (nbL). In the nbL band, some bright stars could be detected from the Girawali site. The performance of TIRCAM-II is discussed in the light of preliminary observations in near infrared bands.

Structure and Infrared Emissivity Properties of the MAO Coatings Formed on TC4 Alloys in K2ZrF6-Based Solution

PubMed Central

Li, Ying; Hu, Dan; Xi, Zhengping

2018-01-01

Micro-arc oxidation (MAO) ceramic coatings were formed on TC4 alloy surface in silicate and metaphosphate electrolytes based with K2ZrF6 for various concentrations. X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) were used to characterize the phase composition, microstructure and chemical compositions of the coatings. The infrared emissivity of the coatings was measured at 50 °C in a wavelength range of 8–20 µm. The microstructural observations all revealed the typical porousstructures. Moreover, adecline in roughness and thickness of the prepared coatings can be observed when the concentration of K2ZrF6 increases. Combined with the results of XRD and XPS, it was found that all the oxides existed as the amorphous form in the coatings except the TiO2 phase. The coatings exhibited the highest infrared emissivity value (about 0.89) when the concentration of K2ZrF6 was 6 g/L, which was possibly attributed to the defect microstructure and the optimal role of ZrO2. PMID:29414841

OISTER optical and near-infrared observations of the super-Chandrasekhar supernova candidate SN 2012dn: Dust emission from the circumstellar shell

NASA Astrophysics Data System (ADS)

Yamanaka, Masayuki; Maeda, Keiichi; Tanaka, Masaomi; Tominaga, Nozomu; Kawabata, Koji S.; Takaki, Katsutoshi; Kawabata, Miho; Nakaoka, Tatsuya; Ueno, Issei; Akitaya, Hiroshi; Nagayama, Takahiro; Takahashi, Jun; Honda, Satoshi; Omodaka, Toshihiro; Miyanoshita, Ryo; Nagao, Takashi; Watanabe, Makoto; Isogai, Mizuki; Arai, Akira; Itoh, Ryosuke; Ui, Takahiro; Uemura, Makoto; Yoshida, Michitoshi; Hanayama, Hidekazu; Kuroda, Daisuke; Ukita, Nobuharu; Yanagisawa, Kenshi; Izumiura, Hideyuki; Saito, Yoshihiko; Masumoto, Kazunari; Ono, Rikako; Noguchi, Ryo; Matsumoto, Katsura; Nogami, Daisaku; Morokuma, Tomoki; Oasa, Yumiko; Sekiguchi, Kazuhiro

2016-10-01

We present extensively dense observations of the super-Chandrasekhar supernova (SC SN) candidate SN 2012dn from -11 to +140 d after the date of its B-band maximum in the optical and near-infrared (NIR) wavelengths conducted through the OISTER ToO (Optical and Infrared Synergetic Telescopes for Education and Research Target of Opportunity) program. The NIR light curves and color evolutions up to 35 days after the B-band maximum provided an excellent match with those of another SC SN 2009dc, providing further support to the nature of SN 2012dn as an SC SN. We found that SN 2012dn exhibited strong excesses in the NIR wavelengths from 30 d after the B-band maximum. The H- and Ks-band light curves exhibited much later maximum dates at 40 and 70 d after the B-band maximum, respectively, compared with those of normal SNe Ia. The H- and Ks-band light curves subtracted by those of SN 2009dc displayed plateaued evolutions, indicating an NIR echo from the surrounding dust. The distance to the inner boundary of the dust shell is limited to 4.8-6.4 × 10-2 pc. No emission lines were found in its early phase spectra, suggesting that the ejecta-circumstellar material interaction could not occur. On the other hand, we found no signature that strongly supports the scenario of dust formation. The mass-loss rate of the pre-explosion system is estimated to be 10-6-10-5 M⊙ yr-1, assuming that the wind velocity of the system is 10-100 km s-1, which suggests that the progenitor of SN 2012dn could be a recurrent nova system. We conclude that the progenitor of this SC SN could be explained by the single-degenerate scenario.

Probing the infrared counterparts of diffuse far-ultraviolet sources in the Galaxy

NASA Astrophysics Data System (ADS)

Saikia, Gautam; Shalima, P.; Gogoi, Rupjyoti; Pathak, Amit

2017-12-01

Recent availability of high quality infrared (IR) data for diffuse regions in the Galaxy and external galaxies have added to our understanding of interstellar dust. A comparison of ultraviolet (UV) and IR observations may be used to estimate absorption, scattering and thermal emission from interstellar dust. In this paper, we report IR and UV observations for selective diffuse sources in the Galaxy. Using archival mid-infrared (MIR) and far-infrared (FIR) observations from Spitzer Space Telescope, we look for counterparts of diffuse far-ultraviolet (FUV) sources observed by the Voyager, Far Ultraviolet Spectroscopic Explorer (FUSE) and Galaxy Evolution Explorer (GALEX) telescopes in the Galaxy. IR emission features at 8 μm are generally attributed to Polycyclic Aromatic Hydrocarbon (PAH) molecules, while emission at 24 μm are attributed to Very Small Grains (VSGs). The data presented here is unique and our study tries to establish a relation between various dust populations. By studying the FUV-IR correlations separately at low and high latitude locations, we have identified the grain component responsible for the diffuse FUV emission.

Herschel GASPS spectral observations of T Tauri stars in Taurus. Unraveling far-infrared line emission from jets and discs

NASA Astrophysics Data System (ADS)

Alonso-Martínez, M.; Riviere-Marichalar, P.; Meeus, G.; Kamp, I.; Fang, M.; Podio, L.; Dent, W. R. F.; Eiroa, C.

2017-07-01

Context. At early stages of stellar evolution young stars show powerful jets and/or outflows that interact with protoplanetary discs and their surroundings. Despite the scarce knowledge about the interaction of jets and/or outflows with discs, spectroscopic studies based on Herschel and ISO data suggests that gas shocked by jets and/or outflows can be traced by far-IR (FIR) emission in certain sources. Aims: We want to provide a consistent catalogue of selected atomic ([OI] and [CII]) and molecular (CO, H2O, and OH) line fluxes observed in the FIR, separate and characterize the contribution from the jet and the disc to the observed line emission, and place the observations in an evolutionary picture. Methods: The atomic and molecular FIR (60-190 μm) line emission of protoplanetary discs around 76 T Tauri stars located in Taurus are analysed. The observations were carried out within the Herschel key programme Gas in Protoplanetary Systems (GASPS). The spectra were obtained with the Photodetector Array Camera and Spectrometer (PACS). The sample is first divided in outflow and non-outflow sources according to literature tabulations. With the aid of archival stellar/disc and jet/outflow tracers and model predictions (PDRs and shocks), correlations are explored to constrain the physical mechanisms behind the observed line emission. Results: Outflow sources exhibit brighter atomic and molecular emission lines and higher detection rates than non-outflow sources. The line detection fractions decrease with SED evolutionary status (from Class I to Class III). We find correlations between [OI] 63.18 μm and [OI] 6300 Å, o-H2O 78.74 μm, CO 144.78 μm, OH 79.12+79.18 μm, and the continuum flux at 24 μm. The atomic line ratios can be explain either by fast (Vshock > 50 km s-1) dissociative J-shocks at low densities (n 103 cm-3) occurring along the jet and/or PDR emission (G0 > 102, n 103-106 cm-3). To account for the [CII] absolute fluxes, PDR emission or UV irradiation of

Roughness effects on thermal-infrared emissivities estimated from remotely sensed images

NASA Astrophysics Data System (ADS)

Mushkin, Amit; Danilina, Iryna; Gillespie, Alan R.; Balick, Lee K.; McCabe, Matthew F.

2007-10-01

Multispectral thermal-infrared images from the Mauna Loa caldera in Hawaii, USA are examined to study the effects of surface roughness on remotely retrieved emissivities. We find up to a 3% decrease in spectral contrast in ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) 90-m/pixel emissivities due to sub-pixel surface roughness variations on the caldera floor. A similar decrease in spectral contrast of emissivities extracted from MASTER (MODIS/ASTER Airborne Simulator) ~12.5-m/pixel data can be described as a function of increasing surface roughness, which was measured remotely from ASTER 15-m/pixel stereo images. The ratio between ASTER stereo images provides a measure of sub-pixel surface-roughness variations across the scene. These independent roughness estimates complement a radiosity model designed to quantify the unresolved effects of multiple scattering and differential solar heating due to sub-pixel roughness elements and to compensate for both sub-pixel temperature dispersion and cavity radiation on TIR measurements.

A SIMPLE CONNECTION BETWEEN THE NEAR- AND MID-INFRARED EMISSION OF GALAXIES AND THEIR STAR FORMATION RATES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mentuch, Erin; Abraham, Roberto G.; Zibetti, Stefano

2010-12-20

We have measured the near-infrared colors and the fluxes of individual pixels in 68 galaxies common to the Spitzer Infrared Nearby Galaxies Survey and the Large Galaxy Atlas Survey. Pixels from each galaxy are grouped into regions of increasingly red near-infrared colors. As expected, the majority of pixels are shown to have relatively constant NIR flux ratios (log{sub 10} I{sub 3.6}/I{sub 1.25} = -0.30 {+-} 0.07 and log{sub 10} I{sub 4.5}/I{sub 3.6} = -0.19 {+-} 0.02), representing the blackbody continuum emission of main sequence stars. However, pixels with red NIR colors correspond to pixels with higher H{sub {alpha}} emission andmore » dust extinction. We show that the NIR colors are correlated to both quantities, with the strongest correlation to the intrinsic H{sub {alpha}} emission. In addition, in regions of high star formation, the average intensity of pixels in red-excess regions (at 1.25 {mu}m, 3.6 {mu}m, 4.5 {mu}m, 5.6 {mu}m, 8.0 {mu}m and 24 {mu}m) scales linearly with the intrinsic intensity of H{alpha} emission, and thus with the star formation rate (SFR) within the pixel. This suggests that most NIR-excess regions are not red because their light is being depleted by absorption. Instead, they are red because additional infrared light is being contributed by a process linked to star formation. This is surprising because the shorter wavelength bands in our study (1.25 {mu}m-5.6 {mu}m) do not probe emission from cold (10-20 K) and warm (50-100 K) dust associated with star formation in molecular clouds. However, emission from hot dust (700-1000 K) and/or polycyclic aromatic hydrocarbon (PAH) molecules can explain the additional emission seen at the shorter wavelengths in our study. The contribution from hot dust and/or PAH emission at 2 {mu}m-5 {mu}m and PAH emission at 5.6 {mu}m and 8.0 {mu}m scales linearly with warm dust emission at 24 {mu}m and the intrinsic H{alpha} emission. Since both are tied to the SFR, our analysis shows that the NIR excess

Far-infrared spectrophotometer for astronomical observations

NASA Technical Reports Server (NTRS)

Moseley, H.; Silverberg, R. F.

1981-01-01

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

The multiple infrared source GL 437

NASA Technical Reports Server (NTRS)

Wynn-Williams, C. G.; Becklin, E. E.; Beichman, C. A.; Capps, R.; Shakeshaft, J. R.

1981-01-01

Infrared and radio continuum observations of the multiple infrared source GL 437 show that it consists of a compact H II region plus two objects which are probably early B stars undergoing rapid mass loss. The group of sources appears to be a multiple system of young stars that have recently emerged from the near side of a molecular cloud. Emission in the unidentified 3.3 micron feature is associated with, but more extended than, the emission from the compact H II region; it probably arises from hot dust grains at the interface between the H II region and the molecular cloud.

SPITZER OBSERVATIONS OF LONG-TERM INFRARED VARIABILITY AMONG YOUNG STELLAR OBJECTS IN CHAMAELEON I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flaherty, Kevin M.; Herbst, William; DeMarchi, Lindsay

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

GEMINI NEAR INFRARED FIELD SPECTROGRAPH OBSERVATIONS OF THE SEYFERT 2 GALAXY MRK 573: IN SITU ACCELERATION OF IONIZED AND MOLECULAR GAS OFF FUELING FLOWS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fischer, Travis C.; Straughn, A. N.; Machuca, C.

2017-01-01

We present near-infrared and optical emission-line and stellar kinematics of the Seyfert 2 galaxy Mrk 573 using the Near-Infrared Field Spectrograph (NIFS) at Gemini North and Dual Imaging Spectrograph at Apache Point Observatory, respectively. By obtaining full kinematic maps of the infrared ionized and molecular gas and stellar kinematics in a ∼700 × 2100 pc{sup 2} circumnuclear region of Mrk 573, we find that kinematics within the Narrow-Line Region are largely due to a combination of both rotation and in situ acceleration of material originating in the host disk. Combining these observations with large-scale, optical long-slit spectroscopy that traces ionized gas emission out tomore » several kpcs, we find that rotation kinematics dominate the majority of the gas. We find that outflowing gas extends to distances less than 1 kpc, suggesting that outflows in Seyfert galaxies may not be powerful enough to evacuate their entire bulges.« less

Gemini Near Infrared Field Spectrograph Observations of the Seyfert 2 Galaxy MRK 573: In Situ Acceleration of Ionized and Molecular Gas Off Fueling Flows

NASA Technical Reports Server (NTRS)

Fischer, Travis C.; Machuca, C.; Diniz, M. R.; Crenshaw, D. M.; Kraemer, S. B.; Riffel, R. A.; Schmitt, H. R.; Baron, F.; Storchi-Bergmann, T.; Straughn, A. N.;

Laser-Induced Breakdown Spectroscopy Infrared Emission From Inorganic and Organic Substances

DTIC Science & Technology

2006-11-01

using a liquid-nitrogen cooled indium antimonide (InSb) detector and the signal was recorded using a gated electronic circuit (boxcar averager). All...contaminants by analyzing the atomic spectral emission lines that result subsequent to plasmas generated by laser power. The ultraviolet-visible-near infrared...UV- Vis-NIR) spectral region exploited in conventional LIBS largely elucidates the elemental composition of the laser target by profiling these

CO OBSERVATIONS AND INVESTIGATION OF TRIGGERED STAR FORMATION TOWARD THE N10 INFRARED BUBBLE AND SURROUNDINGS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gama, D. R. G.; Lepine, J. R. D.; Mendoza, E.

We studied the environment of the dust bubble N10 in molecular emission. Infrared bubbles, first detected by the GLIMPSE survey at 8.0 μ m, 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 {sup 12}CO(1-0) andmore » {sup 13}CO(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.« less

[Ultra] luminous infrared galaxies selected at 90 μm in the AKARI deep field: a study of AGN types contributing to their infrared emission

NASA Astrophysics Data System (ADS)

Małek, K.; Bankowicz, M.; Pollo, A.; Buat, V.; Takeuchi, T. T.; Burgarella, D.; Goto, T.; Malkan, M.; Matsuhara, H.

2017-02-01

Aims: The aim of this work is to characterize physical properties of ultra luminous infrared galaxies (ULIRGs) and luminous infrared galaxies (LIRGs) detected in the far-infrared (FIR) 90 μm band in the AKARI Deep Field-South (ADF-S) survey. In particular, we want to estimate the active galactic nucleus (AGN) contribution to the LIRGs and ULIRGs' infrared emission and which types of AGNs are related to their activity. Methods: We examined 69 galaxies at redshift ≥0.05 detected at 90 μm by the AKARI satellite in the ADF-S, with optical counterparts and spectral coverage from the ultraviolet to the FIR. We used two independent spectral energy distribution fitting codes: one fitting the SED from FIR to FUV (CIGALE) (we use the results from CIGALE as a reference) and gray-body + power spectrum fit for the infrared part of the spectra (CMCIRSED) in order to identify a subsample of ULIRGs and LIRGs, and to estimate their properties. Results: Based on the CIGALE SED fitting, we have found that LIRGs and ULIRGs selected at the 90 μm AKARI band compose 56% of our sample (we found 17 ULIRGs and 22 LIRGs, spanning over the redshift range 0.06 infrared wavelengths. We have detected a significant AGN contribution to the mid-infrared luminosity for 63% of LIRGs and ULIRGs. Our LIRGs contain Type 1, Type 2, and intermediate types of AGN, whereas for ULIRGs, a majority (more than 50%) of AGN emission originates from Type 2 AGNs. The temperature-luminosity and temperature-mass relations for the dust component of ADF-S LIRGs and ULIRGs indicate that these relations are shaped by the dust mass and not by the increased dust heating. Conclusions: We conclude that LIRGs contain Type 1, Type 2, and intermediate types of AGNs, with an AGN contribution to the mid infrared emission at the median level of 13 ± 3

Mid-infrared emission and Raman spectra analysis of Er(3+)-doped oxyfluorotellurite glasses.

PubMed

Chen, Fangze; Xu, Shaoqiong; Wei, Tao; Wang, Fengchao; Cai, Muzhi; Tian, Ying; Xu, Shiqing

2015-04-10

This paper reports on the spectroscopic and structural properties in Er(3+)-doped oxyfluorotellurite glasses. The compositional variation accounts for the evolutions of Raman spectra, Judd-Ofelt parameters, radiative properties, and fluorescent emission. It is found that, when maximum phonon energy changes slightly, phonon density plays a crucial role in quenching the 2.7 μm emission generated by the Er(3+):(4)I11/2→(4)I13/2 transition. The comparative low phonon density contributes strong 2.7 μm emission intensity. The high branching ratio (18.63%) and large emission cross section (0.95×10(-20)  cm(2)) demonstrate that oxyfluorotellurite glass contained with 50 mol.% TeO2 has potential application in the mid-infrared region laser.

Continuous-wave infrared optical gain and amplified spontaneous emission at ultralow threshold by colloidal HgTe quantum dots.

PubMed

Geiregat, Pieter; Houtepen, Arjan J; Sagar, Laxmi Kishore; Infante, Ivan; Zapata, Felipe; Grigel, Valeriia; Allan, Guy; Delerue, Christophe; Van Thourhout, Dries; Hens, Zeger

2018-01-01

Colloidal quantum dots (QDs) raise more and more interest as solution-processable and tunable optical gain materials. However, especially for infrared active QDs, optical gain remains inefficient. Since stimulated emission involves multifold degenerate band-edge states, population inversion can be attained only at high pump power and must compete with efficient multi-exciton recombination. Here, we show that mercury telluride (HgTe) QDs exhibit size-tunable stimulated emission throughout the near-infrared telecom window at thresholds unmatched by any QD studied before. We attribute this unique behaviour to surface-localized states in the bandgap that turn HgTe QDs into 4-level systems. The resulting long-lived population inversion induces amplified spontaneous emission under continuous-wave optical pumping at power levels compatible with solar irradiation and direct current electrical pumping. These results introduce an alternative approach for low-threshold QD-based gain media based on intentional trap states that paves the way for solution-processed infrared QD lasers and amplifiers.

Continuous-wave infrared optical gain and amplified spontaneous emission at ultralow threshold by colloidal HgTe quantum dots

NASA Astrophysics Data System (ADS)

Geiregat, Pieter; Houtepen, Arjan J.; Sagar, Laxmi Kishore; Infante, Ivan; Zapata, Felipe; Grigel, Valeriia; Allan, Guy; Delerue, Christophe; van Thourhout, Dries; Hens, Zeger

2018-01-01

Colloidal quantum dots (QDs) raise more and more interest as solution-processable and tunable optical gain materials. However, especially for infrared active QDs, optical gain remains inefficient. Since stimulated emission involves multifold degenerate band-edge states, population inversion can be attained only at high pump power and must compete with efficient multi-exciton recombination. Here, we show that mercury telluride (HgTe) QDs exhibit size-tunable stimulated emission throughout the near-infrared telecom window at thresholds unmatched by any QD studied before. We attribute this unique behaviour to surface-localized states in the bandgap that turn HgTe QDs into 4-level systems. The resulting long-lived population inversion induces amplified spontaneous emission under continuous-wave optical pumping at power levels compatible with solar irradiation and direct current electrical pumping. These results introduce an alternative approach for low-threshold QD-based gain media based on intentional trap states that paves the way for solution-processed infrared QD lasers and amplifiers.

Submillimeter H2O and H2O+emission in lensed ultra- and hyper-luminous infrared galaxies at z 2-4

NASA Astrophysics Data System (ADS)

Yang, C.; Omont, A.; Beelen, A.; González-Alfonso, E.; Neri, R.; Gao, Y.; van der Werf, P.; Weiß, A.; Gavazzi, R.; Falstad, N.; Baker, A. J.; Bussmann, R. S.; Cooray, A.; Cox, P.; Dannerbauer, H.; Dye, S.; Guélin, M.; Ivison, R.; Krips, M.; Lehnert, M.; Michałowski, M. J.; Riechers, D. A.; Spaans, M.; Valiante, E.

2016-11-01

We report rest-frame submillimeter H2O emission line observations of 11 ultra- or hyper-luminous infrared galaxies (ULIRGs or HyLIRGs) at z 2-4 selected among the brightest lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Using the IRAM NOrthern Extended Millimeter Array (NOEMA), we have detected 14 new H2O emission lines. These include five 321-312ortho-H2O lines (Eup/k = 305 K) and nine J = 2 para-H2O lines, either 202-111(Eup/k = 101 K) or 211-202(Eup/k = 137 K). The apparent luminosities of the H2O emission lines are μLH2O 6-21 × 108 L⊙ (3 <μ< 15, where μ is the lens magnification factor), with velocity-integrated line fluxes ranging from 4-15 Jy km s-1. We have also observed CO emission lines using EMIR on the IRAM 30 m telescope in seven sources (most of those have not yet had their CO emission lines observed). The velocity widths for CO and H2O lines are found to be similar, generally within 1σ errors in the same source. With almost comparable integrated flux densities to those of the high-J CO line (ratios range from 0.4 to 1.1), H2O is found to be among the strongest molecular emitters in high-redshift Hy/ULIRGs. We also confirm our previously found correlation between luminosity of H2O (LH2O) and infrared (LIR) that LH2O LIR1.1-1.2, with ournew detections. This correlation could be explained by a dominant role of far-infrared pumping in the H2O excitation. Modelling reveals that the far-infrared radiation fields have warm dust temperature Twarm 45-75 K, H2O column density per unit velocity interval NH2O /ΔV ≳ 0.3 × 1015 cm-2 km-1 s and 100 μm continuum opacity τ100> 1 (optically thick), indicating that H2O is likely to trace highly obscured warm dense gas. However, further observations of J ≥ 4 H2O lines are needed to better constrain the continuum optical depth and other physical conditions of the molecular gas and dust. We have also detected H2O+ emission in three sources. A tight correlation

Infrared Emission from Kilonovae: The Case of the Nearby Short Hard Burst GRB 160821B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasliwal, Mansi M.; Lau, Ryan M.; Korobkin, Oleg

We present constraints on Ks-band emission from one of the nearest short hard gamma-ray bursts, GRB 160821B, at z = 0.16, at three epochs. We detect a red relativistic afterglow from the jetted emission in the first epoch but do not detect any excess kilonova emission in the second two epochs. We compare upper limits obtained with Keck I/MOSFIRE to multi-dimensional radiative transfer models of kilonovae, that employ composition-dependent nuclear heating and LTE opacities of heavy elements. We discuss eight models that combine toroidal dynamical ejecta and two types of wind and one model with dynamical ejecta only. We alsomore » discuss simple, empirical scaling laws of predicted emission as a function of ejecta mass and ejecta velocity. Our limits for GRB 160821B constrain the ejecta mass to be lower than 0.03 M {sub ⊙} for velocities greater than 0.1 c. At the distance sensitivity range of advanced LIGO, similar ground-based observations would be sufficiently sensitive to the full range of predicted model emission including models with only dynamical ejecta. The color evolution of these models shows that I – K color spans 7–16 mag, which suggests that even relatively shallow infrared searches for kilonovae could be as constraining as optical searches.« less

Infrared Emission from Kilonovae: The Case of the Nearby Short Hard Burst GRB 160821B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasliwal, Mansi M.; Korobkin, Oleg; Lau, Ryan M.

In this paper, we present constraints on Ks-band emission from one of the nearest short hard gamma-ray bursts, GRB 160821B, at z = 0.16, at three epochs. We detect a red relativistic afterglow from the jetted emission in the first epoch but do not detect any excess kilonova emission in the second two epochs. We compare upper limits obtained with Keck I/MOSFIRE to multi-dimensional radiative transfer models of kilonovae, that employ composition-dependent nuclear heating and LTE opacities of heavy elements. We discuss eight models that combine toroidal dynamical ejecta and two types of wind and one model with dynamical ejectamore » only. We also discuss simple, empirical scaling laws of predicted emission as a function of ejecta mass and ejecta velocity. Our limits for GRB 160821B constrain the ejecta mass to be lower than 0.03 M ⊙ for velocities greater than 0.1 c. At the distance sensitivity range of advanced LIGO, similar ground-based observations would be sufficiently sensitive to the full range of predicted model emission including models with only dynamical ejecta. Finally, the color evolution of these models shows that I–K color spans 7–16 mag, which suggests that even relatively shallow infrared searches for kilonovae could be as constraining as optical searches.« less

Infrared Emission from Kilonovae: The Case of the Nearby Short Hard Burst GRB 160821B

DOE PAGES

Kasliwal, Mansi M.; Korobkin, Oleg; Lau, Ryan M.; ...

2017-07-12

In this paper, we present constraints on Ks-band emission from one of the nearest short hard gamma-ray bursts, GRB 160821B, at z = 0.16, at three epochs. We detect a red relativistic afterglow from the jetted emission in the first epoch but do not detect any excess kilonova emission in the second two epochs. We compare upper limits obtained with Keck I/MOSFIRE to multi-dimensional radiative transfer models of kilonovae, that employ composition-dependent nuclear heating and LTE opacities of heavy elements. We discuss eight models that combine toroidal dynamical ejecta and two types of wind and one model with dynamical ejectamore » only. We also discuss simple, empirical scaling laws of predicted emission as a function of ejecta mass and ejecta velocity. Our limits for GRB 160821B constrain the ejecta mass to be lower than 0.03 M ⊙ for velocities greater than 0.1 c. At the distance sensitivity range of advanced LIGO, similar ground-based observations would be sufficiently sensitive to the full range of predicted model emission including models with only dynamical ejecta. Finally, the color evolution of these models shows that I–K color spans 7–16 mag, which suggests that even relatively shallow infrared searches for kilonovae could be as constraining as optical searches.« less

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

Observations of Pulsed Emission from Pulsars

NASA Astrophysics Data System (ADS)

Kramer, Michael

2008-02-01

This brief review summarises what we know observationally about the pulsed emission of pulsars across the electromagnetic spectrum. I describe the wide range of timescales observed in the properties of pulsed emission which cover about 18 orders of magnitude. Future advances in observations capabilities, most notably at gamma-ray and radio frequencies, are expected to significantly enhance our understanding of pulsars and their emission, as a large fraction of our discovery phase space is still unexplored. The first glimpse of the plethora of unknown phenomena yet to be found was given recently by the discovery of new classes of neutron stars such as Rotating Radio Transients (RRATs) and Intermittent Pulsars. We discuss these discoveries and demonstrate how they provide useful information for our understanding of pulsed emission in general.

Preparation, characterization, and infrared emissivity property of optically active polyurethane/TiO{sub 2}/SiO{sub 2} multilayered microspheres

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang Yong; Zhou Yuming, E-mail: ymzhou@seu.edu.cn; Ge Jianhua

Optically active polyurethane/titania/silica (LPU/TiO{sub 2}/SiO{sub 2}) multilayered core-shell composite microspheres were prepared by the combination of titania deposition on the surface of silica spheres and subsequent polymer grafting. LPU/TiO{sub 2}/SiO{sub 2} was characterized by FT-IR, UV-vis spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), SEM and TEM, and the infrared emissivity value (8-14 {mu}m) was investigated in addition. The results indicated that titania and polyurethane had been successfully coated onto the surfaces of silica microspheres. LPU/TiO{sub 2}/SiO{sub 2} exhibited clearly multilayered core-shell construction. The infrared emissivity values reduced along with the increase of covering layers thus provedmore » that the interfacial interactions had direct influence on the infrared emissivity. Besides, LPU/TiO{sub 2}/SiO{sub 2} multilayered microspheres based on the optically active polyurethane took advantages of the orderly secondary structure and strengthened interfacial synergistic actions. Consequently, it possessed the lowest infrared emissivity value. - Graphical Abstract: Optically active polyurethane/titania/silica (LPU/TiO{sub 2}/SiO{sub 2}) multilayered core-shell composite microspheres were prepared by the combination of titania deposition on the surface of silica spheres and subsequent polymer grafting. Highlights: > Optically active polyurethane based on tyrosine was used for the modification of nanoparticles. > LPU/TiO{sub 2}/SiO{sub 2} multilayered core-shell microspheres were prepared and characterized. > Interfacial interactions and secondary structure affected the infrared emissivity of composite.« less

Multispectral Observations of Explosive Gas Emissions from Santiaguito, Guatemala

NASA Astrophysics Data System (ADS)

Carn, S. A.; Watson, M.; Thomas, H.; Rodriguez, L. A.; Campion, R.; Prata, F. J.

2016-12-01

Santiaguito volcano, Guatemala, has been persistently active for decades, producing frequent explosions from its actively growing lava dome. Repeated release of volcanic gases contains information about conduit processes during the cyclical explosions at Santiaguito, but the composition of the gas phase and the amount of volatiles released in each explosion remains poorly constrained. In addition to its persistent activity, Santiaguito offers an exceptional opportunity to investigate lava dome degassing processes since the upper surface of the active lava dome can be viewed from the summit of neighboring Santa Maria. In January 2016 we conducted multi-spectral observations of Santiaguito's explosive eruption plumes and passive degassing from multiple perspectives as part of the first NSF-sponsored `Workshop on Volcanoes' instrument deployment. Gas measurements included open-path Fourier-Transform infrared (OP-FTIR) spectroscopy from the Santa Maria summit, coincident with ultraviolet (UV) and infrared (IR) camera and UV Differential Optical Absorption Spectroscopy (DOAS) from the El Mirador site below Santiaguito's active Caliente lava dome. Using the OP-FTIR in passive mode with the Caliente lava dome as the source of IR radiation, we were able to collect IR spectra at high temporal resolution prior to and during two explosions of Santiaguito on 7-8 January, with volcanic SO2 and H2O emissions detected. UV and IR camera data provide constraints on the total SO2 burden in the emissions (and potentially the volcanic ash burden), which coupled with the FTIR gas ratios provides new constraints on the mass and composition of volatiles driving explosions at Santiaguito. All gas measurements indicate significant volatile release during explosions with limited degassing during repose periods. In this presentation we will present ongoing analysis of the unique Santiaguito gas dataset including estimation of the total volatile mass released in explosions and an

Uncovering the Spectral Energy Distribution in Active Galaxies Using High Ionization Mid-Infrared Emission Lines

NASA Technical Reports Server (NTRS)

Melendez, M.; Kraemer, S. B.; Weaver, K. A.; Mushotzky, R. F.

2011-01-01

The shape of the spectral energy distribution of active galaxies in the EUV soft X-ray band (13.6 eV to 1 keV) is uncertain because obscuration by dust and gas can hamper our view of the continuum. To investigate the shape of the spectral energy distribution in this energy band, we have generated a set of photoionization models which reproduce the small dispersion found in correlations between high-ionization mid-infrared emission lines in a sample of hard X-ray selected AGN. Our calculations show that a broken power-law continuum model is sufficient to reproduce the [Ne V]14.32 microns/[Ne III], [Ne V]24.32 microns/[O IV]25.89 micron and [O IV] 25.89 microns/[Ne III] ratios, and does not require the addition of a "big bump" EUV model component. We constrain the EUV-soft X-ray slope, alpha(sub i), to be between 1.5 - 2.0 and derive a best fit of alpha(sub i) approx. 1.9 for Seyfert 1 galaxies, consistent with previous studies of intermediate redshift quasars. If we assume a blue bump model, most sources in our sample have derived temperatures between T(sub BB) = 10(exp 5.18) K to 10(exp 5.7) K, suggesting that the peak of this component spans a large range of energies extending from approx. (Lambda)600 A to > (Lambda)1900 A. In this case, the best fitting peak energy that matches the mid-infrared line ratios of Seyfert 1 galaxies occurs between approx. (Lambda)700-(Lambda)1000 A. Despite the fact that our results do not rule out the presence of an EUV bump, we conclude that our power-law model produces enough photons with energies > 4 Ry to generate the observed amount of mid-infrared emission in our sample of BAT AGN.

Infrared Auroral Emissions Driven by Resonant Electron Impact Excitation of NO Molecules

NASA Astrophysics Data System (ADS)

Campbell, L.; Brunger, M. J.; Petrovic, Z. Lj.; Jelisavcic, M.; Panajotovic, R.; Buckman, S. J.

2004-05-01

Although only a minor constituent of the earth's upper atmosphere, nitric oxide (NO) plays a major role in infrared auroral emissions due to radiation from vibrationally excited (NO*) states. The main process leading to the production of these excited molecules was thought to be chemiluminescence, whereby excited nitrogen atoms interact with oxygen molecules to form vibrationally excited nitric oxide (NO*) and atomic oxygen. Here we show evidence that a different production mechanism for NO*, due to low energy electron impact excitation of NO molecules, is responsible for more than 30% of the NO auroral emission near 5 μm.

Developing Novel Fluorescent Materials with Near Infrared Emission by Using m-Phenylene

NASA Technical Reports Server (NTRS)

Pang, Yi; Liao, Ling; Meador, Michael A.

2003-01-01

Our research focuses on development of novel p-conjugated polymers with desired emission. In the current study, the structure of a highly green-emitting poly[(m-phenylenevinylene)- alt-( p-phenylenevinylene)] has been modified by increasing the content of p-phenylene to achieve red- and infrared-emission. The polymer is synthesized via Wittig-Horner condensation, which is known to lead to trans-olefin linkage. The polymer is soluble in common organic solvents such as toluene, chloroform and THF. The spectroscopic properties of the polymer in both solution and film states will be discussed in comparison with its model compound.

Top-Down CO Emissions Based On IASI Observations and Hemispheric Constraints on OH Levels

NASA Astrophysics Data System (ADS)

Müller, J.-F.; Stavrakou, T.; Bauwens, M.; George, M.; Hurtmans, D.; Coheur, P.-F.; Clerbaux, C.; Sweeney, C.

2018-02-01

Assessments of carbon monoxide emissions through inverse modeling are dependent on the modeled abundance of the hydroxyl radical (OH) which controls both the primary sink of CO and its photochemical source through hydrocarbon oxidation. However, most chemistry transport models (CTMs) fall short of reproducing constraints on hemispherically averaged OH levels derived from methylchloroform (MCF) observations. Here we construct five different OH fields compatible with MCF-based analyses, and we prescribe those fields in a global CTM to infer CO fluxes based on Infrared Atmospheric Sounding Interferometer (IASI) CO columns. Each OH field leads to a different set of optimized emissions. Comparisons with independent data (surface, ground-based remotely sensed, aircraft) indicate that the inversion adopting the lowest average OH level in the Northern Hemisphere (7.8 × 105 molec cm-3, ˜18% lower than the best estimate based on MCF measurements) provides the best overall agreement with all tested observation data sets.

Uncooled emissive infrared imagers for CubeSats

NASA Astrophysics Data System (ADS)

Puschell, Jeffery J.; Masini, Paolo

2014-09-01

Raytheon's fourth generation uncooled microbolometer array technology with digital output, High Definition (HD) 1920 × 1200 format and 12 μm cell size enables uncooled thermal infrared (TIR) multispectral imagers with the sensitivity and spatial sampling needed for a variety of Earth observation missions in LEO, GEO and HEO. A powerful combination of small detector cell size, fast optics and high sensitivity achieved without cryogenic cooling leads to instruments that are much smaller than current TIR systems, while still offering the capability to meet challenging measurement requirements for Earth observation missions. To consider how this technology could be implemented for Earth observation missions, we extend our previous studies with visible wavelength CubeSat imagers for environmental observations from LEO and examine whether small thermal infrared imagers based on fourth generation uncooled technology could be made small enough to fit onboard a 3U CubeSat and still meet challenging requirements for legacy missions. We found that moderate spatial resolution (~200 m) high sensitivity cloud and surface temperature observations meeting legacy MODIS/VIIRS requirements could be collected successfully with CubeSat-sized imagers but that multiple imagers are needed to cover the full swath for these missions. Higher spatial resolution land imagers are more challenging to fit into the CubeSat form factor, but it may be possible to do so for systems that require roughly 100 m spatial resolution. Regardless of whether it can fit into a CubeSat or not, uncooled land imagers meeting candidate TIR requirements can be implemented with a much smaller instrument than previous imagers. Even though this technology appears to be very promising, more work is needed to qualify this newly available uncooled infrared technology for use in space. If these new devices prove to be as space worthy as the first generation arrays that Raytheon qualified and built into the THEMIS imager

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.

Core Emergence in a Massive Infrared Dark Cloud: A Comparison between Mid-IR Extinction and 1.3 mm Emission

NASA Astrophysics Data System (ADS)

Kong, Shuo; Tan, Jonathan C.; Arce, Héctor G.; Caselli, Paola; Fontani, Francesco; Butler, Michael J.

2018-03-01

Stars are born from dense cores in molecular clouds. Observationally, it is crucial to capture the formation of cores in order to understand the necessary conditions and rate of the star formation process. The Atacama Large Millimeter/submillimeter Array (ALMA) is extremely powerful for identifying dense gas structures, including cores, at millimeter wavelengths via their dust continuum emission. Here, we use ALMA to carry out a survey of dense gas and cores in the central region of the massive (∼105 M ⊙) infrared dark cloud (IRDC) G28.37+0.07. The observation consists of a mosaic of 86 pointings of the 12 m array and produces an unprecedented view of the densest structures of this IRDC. In this first Letter about this data set, we focus on a comparison between the 1.3 mm continuum emission and a mid-infrared (MIR) extinction map of the IRDC. This allows estimation of the “dense gas” detection probability function (DPF), i.e., as a function of the local mass surface density, Σ, for various choices of thresholds of millimeter continuum emission to define “dense gas.” We then estimate the dense gas mass fraction, f dg, in the central region of the IRDC and, via extrapolation with the DPF and the known Σ probability distribution function, to the larger-scale surrounding regions, finding values of about 5% to 15% for the fiducial choice of threshold. We argue that this observed dense gas is a good tracer of the protostellar core population and, in this context, estimate a star formation efficiency per free-fall time in the central IRDC region of ɛ ff ∼ 10%, with approximately a factor of two systematic uncertainties.

Anthropogenic emissions and space-borne observations of carbon monoxide over South Asia

NASA Astrophysics Data System (ADS)

Ul-Haq, Zia; Tariq, Salman; Ali, Muhammad

2016-11-01

The focus of this study is to understand anthropogenic emissions, spatiotemporal variability and trends of carbon monoxide (CO) over South Asia by using datasets from MACCity (Monitoring Atmospheric Composition and Climate, MACC and megaCITY - Zoom for the Environment, CityZEN), REAS (Regional Emission inventory in Asia), AIRS (Atmospheric Infrared Sounder) and SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY). MACCity anthropogenic emissions show an overall increase of 16.5% during 2000-2010. Elevated levels of MACCity CO are found in Indo-Gangetic Basin (IGB), eastern mining region of India, Bangladesh and large urban areas. Some of the major contributors of these emissions have been identified as agricultural waste burning, land transport, industrial production, and energy generation and distribution. An area averaged mean value of AIRS CO at 600 hPa is found to be 114 ± 2 ppbv (slope -0.48 ± 0.2 ppbv yr-1, y-intercept 117 ± 1 ppbv and r = 0.68) with a minor declining trend at -0.41 ± 0.18% yr-1 over the region during 2003-2015. A strong seasonality in AIRS CO concentration is observed with spring season peak in March 129 ± 1.9 ppbv, whereas low values have been observed in summer monsoon with sturdy dip in July 99.6 ± 1.94 ppbv. AIRS CO and SCIAMACHY CO Total Column (CO TC) over the study region show spatial patterns similar to MACCity and REAS emissions. An analysis of SCIAMACHY CO TC tendencies has been performed which indicates minor rising trends over some parts of the region. Background CO, Recent Emissions (RE), and spatial anomalies in RE over high anthropogenic activity zones of Indus Basin, Ganges Basin and Eastern Region were analyzed using AIRS and SCIAMACHY CO data.

Coherent infrared emission from myoglobin crystals: An electric field measurement

PubMed Central

Groot, Marie-Louise; Vos, Marten H.; Schlichting, Ilme; van Mourik, Frank; Joffre, Manuel; Lambry, Jean-Christophe; Martin, Jean-Louis

2002-01-01

We introduce coherent infrared emission interferometry as a χ(2) vibrational spectroscopy technique and apply it to studying the initial dynamics upon photoactivation of myoglobin (Mb). By impulsive excitation (using 11-fs pulses) of a Mb crystal, vibrations that couple to the optical excitation are set in motion coherently. Because of the order in the crystal lattice the coherent oscillations of the different proteins in the crystal that are associated with charge motions give rise to a macroscopic burst of directional multi-teraHertz radiation. This radiation can be detected in a phase-sensitive way by heterodyning with a broad-band reference field. In this way both amplitude and phase of the different vibrations can be obtained. We detected radiation in the 1,000–1,500 cm−1 frequency region, which contains modes sensitive to the structure of the heme macrocycle, as well as peripheral protein modes. Both in carbonmonoxy-Mb and aquomet-Mb we observed emission from six modes, which were assigned to heme vibrations. The phase factors of the modes contributing to the protein electric field show a remarkable consistency, taking on values that indicate that the dipoles are created “emitting” at t = 0, as one would expect for impulsively activated modes. The few deviations from this behavior in Mb-CO we propose are the result of these modes being sensitive to the photodissociation process and severely disrupted by it. PMID:11818575

Infrared emission associated with chemical reactions on Shuttle and SIRTF surfaces

NASA Technical Reports Server (NTRS)

Hollenbach, D. J.; Tielens, Alexander G. G. M.

1984-01-01

The infrared intensities which would be observed by the Shuttle Infrared Telescope Facility (SIRTF), and which are produced by surface chemistry following atmospheric impact on SIRTF and the shuttle are estimated. Three possible sources of reactants are analyzed: (1) direct atmospheric and scattered contaminant fluxes onto the shuttle's surface; (2) direct atmospheric and scattered contaminant fluxes onto the SIRTF sunshade; and (3) scattered fluxes onto the cold SIRTF mirror. The chemical reactions are primarily initiated by the dominent flux of reactive atomic oxygen on the surfaces. Using observations of the optical glow to constrain theoretical parameters, it is estimated for source (1) that the infrared glow on the SIRTF mirror will be comparable to the zodiacal background between 1 and 10 micron wavelengths. It is speculated that oxygen reacts with the atoms and the radicals bound in the organic molecules that reside on the shuttle and the Explorer surfaces. It is concluded that for source (2) that with suitable construction, a warm sunshade will produce insignificant infrared glow. It is noted that the atomic oxygen flux on the cold SIRTF mirror (3) is insufficient to produce significant infrared glow. Infrared absorption by the ice buildup on the mirror is also small.

Dust silicate emission in FIR/submm

NASA Astrophysics Data System (ADS)

Coupeaud, A.; Demyk, K.; Mény, C.; Nayral, C.

2010-12-01

The far-infrared to millimeter wavelength (FIR-mm) range in astronomical observations is dominated by the thermal emission from large (10-100 nm) and cold (10-20 K) dust grains, which are in thermal equilibrium with the interstellar radiation field. However, the physics of the FIR-mm emission from such cold matter is not well understood as shown by the observed dependence with the temperature of the spectral index of the dust emissivity β and by the observed far infrared excess. Interestingly, a similar behaviour is observed in experiments of characterization of the spectral properties of dust analogues. We present a study of the optical properties of analogues of interstellar silicate grains at low temperature in the FIR/submm range aiming to understand their peculiar behaviour. Such studies are essential for the interpretation of the Herschel and Planck data.

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.

Radio emission from dusty galaxies observed by AKARI

NASA Astrophysics Data System (ADS)

Pepiak, A.; Pollo, A.; Takeuchi, T. T.; Solarz, A.; Jurusik, W.

2014-10-01

We probe radio-infrared correlation for two samples of extragalactic sources from the local Universe from the AKARI All-Sky Catalogue. The first, smaller sample (1053 objects) was constructed by the cross-correlation of the AKARI/FIS All-Sky Survey Bright Source Catalogue, the AKARI IRC All-Sky Survey Point Source Catalogue and the NRAO VLA Sky Survey, i.e. it consists of sources detected in the mid- and far-infrared by AKARI, and at the 1.4 GHz radio frequency by NRAO. The second, larger sample (13,324 objects) was constructed by the cross-correlation of only the AKARI/FIS All-Sky Survey Bright Source Catalogue and the NRAO VLA Sky Survey, i.e. it consists of sources detected in the far-infrared and radio, without a condition to be detected in the mid-infrared. Additionally, all objects in both samples were identified as galaxies in the NED and/or SIMBAD databases, and a part of them is known to host active galactic nuclei (AGNs). For the present analysis, we have restricted our samples only to sources with known redshift z. In this paper, we analyse the far-infrared-radio correlation for both of these samples. We compare the ratio of infrared and radio emission from normal star-forming dusty galaxies and AGNs in both samples. For the smaller sample we obtained =2.14 for AGNs and =2.27 for normal galaxies, while for the larger sample =2.15 for AGNs and =2.22 for normal galaxies. An average value of the slope in both samples is ~2.2, which is consistent with the previous measurements from the literature.

Estimation of Methane Emissions in the Los Angeles Basin using CLARS-FTS Observations

NASA Astrophysics Data System (ADS)

Sander, S.; Zeng, Z. C.; Pongetti, T.; Duren, R. M.; Shia, R. L.; Yung, Y. L.; He, L.; Gurney, K. R.

2017-12-01

The Los Angeles Basin (LA Basin), covering almost 10,743 square miles, is home to over 16.8 million people - about half the population of the state of California. It is also the second most populated urban area in the United States and one of the major source of anthropogenic greenhouse gases. Using FTIR observations from the California Laboratory for Atmospheric Remote Sensing (CLARS) located on Mount Wilson at an altitude of 1673m, we measure the reflected near infrared sunlight from 33 surface targets in the Los Angeles megacity including the direct solar beam which gives the free tropospheric background. We then retrieve the excess slant column abundances of important trace gases such as carbon dioxide (CO2) and methane (CH4) in the LA basin. Using atmospheric tracer - tracer correlations for CH4 and CO2 to eliminate the effect of aerosol scattering in the retrieval, we infer methane emissions based on the ratio of XCH4 excess to XCO2 excess. Significant variability is observed in the spatial distributions of excess CH4. Methane emissions in the LA basin show consistent peaks in late summer and winter during the period from Sep 2011 to the present. The strong correlation between natural gas usage data and derived CLARS methane emissions (r2 = 0.5) implies that natural gas leakage during transmission and/or consumption accounts for a significant fraction of the inferred seasonal variability of methane emissions in the LA basin. We will report updated annual trends in CH4 emissions from 2011 to the present. Copyright 2017. All rights reserved.

Long Fading Mid-infrared Emission in Transient Coronal Line Emitters: Dust Echo of a Tidal Disruption Flare

NASA Astrophysics Data System (ADS)

Dou, Liming; Wang, Ting-gui; Jiang, Ning; Yang, Chenwei; Lyu, Jianwei; Zhou, Hongyan

2016-12-01

The sporadic accretion following the tidal disruption of a star by a super-massive black hole (TDE) leads to a bright UV and soft X-ray flare in the galactic nucleus. The gas and dust surrounding the black hole responses to such a flare with an echo in emission lines and infrared emission. In this paper, we report the detection of long fading mid-IR emission lasting up to 14 years after the flare in four TDE candidates with transient coronal lines using the WISE public data release. We estimate that the reprocessed mid-IR luminosities are in the range between 4× {10}42 and 2× {10}43 erg s-1 and dust temperature in the range of 570-800 K when WISE first detected these sources three to five years after the flare. Both luminosity and dust temperature decrease with time. We interpret the mid-IR emission as the infrared echo of the tidal disruption flare. We estimate the UV luminosity at the peak flare to be 1 to 30 times 1044 erg s-1 and that for warm dust masses to be in the range of 0.05-1.3 {M}⊙ within a few parsecs. Our results suggest that the mid-infrared echo is a general signature of TDE in the gas-rich environment.

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

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.

Jupiter's atmospheric composition from the Cassini thermal infrared spectroscopy experiment

NASA Technical Reports Server (NTRS)

Kunde, V. G.; Flasar, F. M.; Jennings, D. E.; Bezard, B.; Strobel, D. F.; Conrath, B. J.; Nixon, C. A.; Bjoraker, G. L.; Romani, P. N.; Achterberg, R. K.;

Infrared dust and millimeter-wave carbon monoxide emission in the Orion region

NASA Technical Reports Server (NTRS)

Bally, John; Langer, William D.; Liu, Weihong

1991-01-01

The far-infrared dust emission seen by the IRAS satellite in the Orion region is analyzed as a function of the local radiation field intensity, and the dust temperature and opacity are compared with (C-12)O and (C-13)O emission. The infrared radiation is interpreted within the framework of a single-component large grain model and a multicomponent grain model consisting of subpopulations of grains with size-dependent temperatures. A strong dependence of the 100-micron optical depth derived is found using the large grain model on the average line-of-sight dust temperature and radiation field. In the hot environment surrounding high-luminosity sources and H II regions, all dust along the line-of-sight radiates at 100 microns, and the dust-to-gas ratio, based on the 100-micron opacity and I(/C-13/O), appears to be in agreement with the standard value, about 1 percent by mass. A relationship is found between the inferred dust-to-gas ratio and the radiation field intensity responsible for heating the dust which can be used to estimate the gas column density from the dust opacity derived from the 60- and 100-micron IRAS fluxes.

Quantifying direct carbon dioxide emissions from wastewater treatment units by nondispersive infrared sensor (NDIR) - A pilot study.

PubMed

Kosse, Pascal; Kleeberg, Tasja; Lübken, Manfred; Matschullat, Jörg; Wichern, Marc

2018-08-15

Treatment of nutrient-rich wastewater potentially results in direct release of greenhouse gases (GHGs) such as CO 2 , N 2 O or CH 4 - and thus affects Waste Water Treatment Plant's carbon footprint. Accurate CO 2 quantification is challenging due to various chemical, physical and operational conditions. A floating chamber equipped with a nondispersive infrared, single beam, dual wavelength sensor has been evaluated for a pilot approach to quantify fugitive CO 2 emissions above different wastewater treatment units. Total average CO 2 flux was 1182gCO 2 ·m -2 ·d -1 with minimum and maximum fluxes of 829gCO 2 ·m -2 ·d -1 and 1493gCO 2 ·m -2 ·d -1 , respectively. Total observed CO 2 emissions were in 7 to 17kgCO 2 ·PE -1 ·a -1 (average 12kgCO 2 ·PE -1 ·a -1 ). The nitrification tank accounted for about 94.3% of the emissions, followed by secondary clarification (ca. 4.3%) and denitrification (ca. 1.4%), based on those average annual CO 2 emissions per population equivalent (PE). Copyright © 2018 Elsevier B.V. All rights reserved.

AKARI/IRC NEAR-INFRARED SPECTRAL ATLAS OF GALACTIC PLANETARY NEBULAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohsawa, Ryou; Onaka, Takashi; Sakon, Itsuki

2016-04-15

Near-infrared (2.5–5.0 μm) low-resolution (λ/Δλ ∼ 100) spectra of 72 Galactic planetary nebulae (PNe) were obtained with the Infrared Camera (IRC) in the post-helium phase. The IRC, equipped with a 1′ × 1′ window for spectroscopy of a point source, was capable of obtaining near-infrared spectra in a slit-less mode without any flux loss due to a slit. The spectra show emission features including hydrogen recombination lines and the 3.3–3.5 μm hydrocarbon features. The intensity and equivalent width of the emission features were measured by spectral fitting. We made a catalog providing unique information on the investigation of the near-infrared emission ofmore » PNe. In this paper, details of the observations and characteristics of the catalog are described.« less

Far-Infrared sources and diffuse emission in M31

NASA Technical Reports Server (NTRS)

Xu, Cong; Helou, George

1994-01-01

A study on the far-infrared (FIR) emission of M31 has been carried out with the High Resolution (HiRes) maps (approx. 1 min) derived from IRAS data. Sixty-eight FIR sources are detected in M31, which in general coincide with optical HII regions, and contribute 15, 23, 29, and 23 percent to the fluxes in 12, 25, 60, and 100 micron bands, respectively. The remaining diffuse emission, which dominates the FIR emission of M31, is studied using a dust heating model which utilizes the UV and optical photometry maps and the HI maps available in the literature. It is found that the global dust-to-gas ratio in M31 disk is 6.5 10(exp -3), very close to the dust-to-gas ratio in the solar neighborhood. There is a significant galactocentric gradient of the dust-to-HI-gas ratio, with an e-folding scale length of 9 kpc. The diffuse dust correlates tightly with the HI gas. The model indicates that the non-ionizing UV (913-4000A) radiation from massive and intermediate massive stars contributes only about 30 percent of the heating of the diffuse dust, while the optical-NIR (4000-9000A) radiation from the old stellar population is responsible for the most of the heating.

Observational limitations of Bose-Einstein photon statistics and radiation noise in thermal emission

NASA Astrophysics Data System (ADS)

Lee, Y.-J.; Talghader, J. J.

2018-01-01

For many decades, theory has predicted that Bose-Einstein statistics are a fundamental feature of thermal emission into one or a few optical modes; however, the resulting Bose-Einstein-like photon noise has never been experimentally observed. There are at least two reasons for this: (1) Relationships to describe the thermal radiation noise for an arbitrary mode structure have yet to be set forth, and (2) the mode and detector constraints necessary for the detection of such light is extremely hard to fulfill. Herein, photon statistics and radiation noise relationships are developed for systems with any number of modes and couplings to an observing space. The results are shown to reproduce existing special cases of thermal emission and are then applied to resonator systems to discuss physically realizable conditions under which Bose-Einstein-like thermal statistics might be observed. Examples include a single isolated cavity and an emitter cavity coupled to a small detector space. Low-mode-number noise theory shows major deviations from solely Bose-Einstein or Poisson treatments and has particular significance because of recent advances in perfect absorption and subwavelength structures both in the long-wave infrared and terahertz regimes. These microresonator devices tend to utilize a small volume with few modes, a regime where the current theory of thermal emission fluctuations and background noise, which was developed decades ago for free-space or single-mode cavities, has no derived solutions.

CO2 infrared emission as a diagnostic of planet-forming regions of disks

NASA Astrophysics Data System (ADS)

Bosman, Arthur D.; Bruderer, Simon; van Dishoeck, Ewine F.

2017-05-01

Context. The infrared ro-vibrational emission lines from organic molecules in the inner regions of protoplanetary disks are unique probes of the physical and chemical structure of planet-forming regions and the processes that shape them. These observed lines are mostly interpreted with local thermal equilibrium (LTE) slab models at a single temperature. Aims: We aim to study the non-LTE excitation effects of carbon dioxide (CO2) in a full disk model to evaluate: (I) what the emitting regions of the different CO2 ro-vibrational bands are; (II) how the CO2 abundance can be best traced using CO2 ro-vibrational lines using future JWST data and; (III) what the excitation and abundances tell us about the inner disk physics and chemistry. CO2 is a major ice component and its abundance can potentially test models with migrating icy pebbles across the iceline. Methods: A full non-LTE CO2 excitation model has been built starting from experimental and theoretical molecular data. The characteristics of the model are tested using non-LTE slab models. Subsequently the CO2 line formation was modelled using a two-dimensional disk model representative of T Tauri disks where CO2 is detected in the mid-infrared by the Spitzer Space Telescope. Results: The CO2 gas that emits in the 15 μm and 4.5 μm regions of the spectrum is not in LTE and arises in the upper layers of disks, pumped by infrared radiation. The v2 15 μm feature is dominated by optically thick emission for most of the models that fit the observations and increases linearly with source luminosity. Its narrowness compared with that of other molecules stems from a combination of the low rotational excitation temperature ( 250 K) and the inherently narrower feature for CO2. The inferred CO2 abundances derived for observed disks range from 3 × 10-9 to 1 × 10-7 with respect to total gas density for typical gas/dust ratios of 1000, similar to earlier LTE disk estimates. Line-to-continuum ratios are low, in the order of a

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.

Wide-field Infrared Survey Explorer

NASA Technical Reports Server (NTRS)

Padgett, Deborah

2012-01-01

We present WISE (Wide-field Infrared Survey Explorer) mid-infrared photometry of young stellar object candidates in the Canis Majoris clouds at a distance of 1 kpc. WISE has identified 682 objects with apparent 12 and 22 micron excess emission in a 7 deg x 10 deg field around the CMa Rl cloud . While a substantial fraction of these candidates are likely galaxies, AGB stars, and artifacts from confusion along the galactic plane, others are part of a spectacular cluster of YSOs imaged by WISE along a dark filament in the R1 cloud. Palomar Double Spectrograph observations of several sources in this cluster confirm their identity as young A and B stars with strong emission lines. In this contribution, we plot the optical -mid-infrared spectral energy distribution for the WISE YSO candidates and discuss potential contaminants to the sample . The data demonstrate the utility of WISE in performing wide-area surveys for young stellar objects.

An infrared flash contemporaneous with the gamma-rays of GRB 041219a.

PubMed

Blake, C H; Bloom, J S; Starr, D L; Falco, E E; Skrutskie, M; Fenimore, E E; Duchêne, G; Szentgyorgyi, A; Hornstein, S; Prochaska, J X; McCabe, C; Ghez, A; Konopacky, Q; Stapelfeldt, K; Hurley, K; Campbell, R; Kassis, M; Chaffee, F; Gehrels, N; Barthelmy, S; Cummings, J R; Hullinger, D; Krimm, H A; Markwardt, C B; Palmer, D; Parsons, A; McLean, K; Tueller, J

2005-05-12

The explosion that results in a cosmic gamma-ray burst (GRB) is thought to produce emission from two physical processes: the central engine gives rise to the high-energy emission of the burst through internal shocking, and the subsequent interaction of the flow with the external environment produces long-wavelength afterglows. Although observations of afterglows continue to refine our understanding of GRB progenitors and relativistic shocks, gamma-ray observations alone have not yielded a clear picture of the origin of the prompt emission nor details of the central engine. Only one concurrent visible-light transient has been found and it was associated with emission from an external shock. Here we report the discovery of infrared emission contemporaneous with a GRB, beginning 7.2 minutes after the onset of GRB 041219a (ref. 8). We acquired 21 images during the active phase of the burst, yielding early multi-colour observations. Our analysis of the initial infrared pulse suggests an origin consistent with internal shocks.

Infrared observations of anonymous IRC sources

NASA Technical Reports Server (NTRS)

Strecker, D. W.; Ney, E. P.

1974-01-01

Infrared (0.9 to 18 microns) observations of 232 anonymous 2-micron Sky survey (IRC) sources are reported. Most of the objects appear to be late-type stars with little or no long-wave excess. About ten percent exhibit large excesses. Thirty-one of the brightest 11-micron sources have been remeasured to determine variability. These brighter objects appear to fall into two groups; one group resembles NML Tauri, while the other is like NML Cygni.

Infrared non-destructive evaluation method and apparatus

DOEpatents

Baleine, Erwan; Erwan, James F; Lee, Ching-Pang; Stinelli, Stephanie

2014-10-21

A method of nondestructive evaluation and related system. The method includes arranging a test piece (14) having an internal passage (18) and an external surface (15) and a thermal calibrator (12) within a field of view (42) of an infrared sensor (44); generating a flow (16) of fluid characterized by a fluid temperature; exposing the test piece internal passage (18) and the thermal calibrator (12) to fluid from the flow (16); capturing infrared emission information of the test piece external surface (15) and of the thermal calibrator (12) simultaneously using the infrared sensor (44), wherein the test piece infrared emission information includes emission intensity information, and wherein the thermal calibrator infrared emission information includes a reference emission intensity associated with the fluid temperature; and normalizing the test piece emission intensity information against the reference emission intensity.

TIRCAM2: The TIFR near infrared imaging camera

NASA Astrophysics Data System (ADS)

Naik, M. B.; Ojha, D. K.; Ghosh, S. K.; Poojary, S. S.; Jadhav, R. B.; Meshram, G. S.; Sandimani, P. R.; Bhagat, S. B.; D'Costa, S. L. A.; Gharat, S. M.; Bakalkar, C. B.; Ninan, J. P.; Joshi, J. S.

2012-12-01

TIRCAM2 (TIFR near infrared imaging camera - II) is a closed cycle cooled imager that has been developed by the Infrared Astronomy Group at the Tata Institute of Fundamental Research for observations in the near infrared band of 1 to 3.7 μm with existing Indian telescopes. In this paper, we describe some of the technical details of TIRCAM2 and report its observing capabilities, measured performance and limiting magnitudes with the 2-m IUCAA Girawali telescope and the 1.2-m PRL Gurushikhar telescope. The main highlight is the camera's capability of observing in the nbL (3.59 mum) band enabling our primary motivation of mapping of Polycyclic Aromatic Hydrocarbon (PAH) emission at 3.3 mum.

Infrared observations of metal-deficient stars

NASA Astrophysics Data System (ADS)

Arribas, S.; Martinez Roger, C.

1987-09-01

Infrared magnitudes in the J, H, K and L bands for 64 metal-deficient stars spanning a wide range in effective temperature, luminosity and metal content are presented. An accuracy of 0.02 magnitude is obtained for the JHK bands and 0.03 for the L filter. Infrared-infrared and optical-infrared colour-colour diagrams are discussed and compared with the mean intrinsic tracks for Population I stars. It is concluded that infrared colours are not notably dependent on metallicity, with some exceptions for the reddest giants, which can be also interpreted by residual effects in the transformation equations between different systems. The authors also discuss briefly the near infrared photometric system of the Observatorio del Teide, from the Instituto de Astrofisica de Canarias.

SOFIA/FORCAST Resolves 30 - 40 μm Extended Emission in Nearby AGN

NASA Astrophysics Data System (ADS)

Fuller, Lindsay; Lopez-Rodriguez, Enrique; Packham, Christopher C.; Ichikawa, Kohei; Togi, Aditya

2018-06-01

We present arcsecond-scale observations in the 30 - 40 μm range of seven nearby Seyfert galaxies observed from the Stratospheric Observatory For Infrared Astronomy (SOFIA) using the 31.5 and 37.1 μm filters of the Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST). We find extended diffuse emission in the 37.1 μm images in our sample, and isolate this from unresolved torus emission. Using Spitzer/IRS spectra, we determine the dominant mid-infrared (MIR) emission source and attribute it to dust in the narrow line region (NLR) or star formation. We compare the optical NLR and radio jet axes to the extended 37.1 μm emission and find coincident axes for three sources.

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

Mineral Information Extraction Based on GAOFEN-5'S Thermal Infrared Data

NASA Astrophysics Data System (ADS)

Liu, L.; Shang, K.

2018-04-01

Gaofen-5 carries six instruments aimed at various land and atmosphere applications, and it's an important unit of China High-resolution Earth Observation System. As Gaofen-5's thermal infrared payload is similar to that of ASTER, which is widely used in mineral exploration, application of Gaofen-5's thermal infrared data is discussed regarding its capability in mineral classification and silica content estimation. First, spectra of silicate, carbonate, sulfate minerals from a spectral library are used to conduct spectral feature analysis on Gaofen-5's thermal infrared emissivities. Spectral indices of band emissivities are proposed, and by setting thresholds of these spectral indices, it can classify three types of minerals mentioned above. This classification method is tested on a simulated Gaofen-5 emissivity image. With samples acquired from the study area, this method is proven to be feasible. Second, with band emissivities of silicate and their silica content from the same spectral library, correlation models have been tried to be built for silica content inversion. However, the highest correlation coefficient is merely 0.592, which is much lower than that of correlation model built on ASTER thermal infrared emissivity. It can be concluded that GF-5's thermal infrared data can be utilized in mineral classification but not in silica content inversion.

OT2_pgolds01_6: Herschel [NII] Observations to Define the Source of [CII] Emission

NASA Astrophysics Data System (ADS)

Goldsmith, P.

2011-09-01

The 158 micron line of ionized carbon is the strongest single long-wavelength emission feature from the interstellar medium and is the most important coolant of gas in which hydrogen is in atomic form. It is a key determinant of the evolution of these largely atomic regions into denser, cooler molecular clouds in which new stars are formed, and is widely used as a tracer of star formation in the Milky Way and other galaxies. There is, however, an ongoing, serious controversy about the origin of the [CII] emission, which has been asserted to come from the extended low-density warm interstellar medium, but has more generally been associated with the primarily molecular photon dominated regions (PDRs) intimately associated with massive, young stars. We propose a combined HIFI and PACS study of the two far-infrared [NII] fine structure lines in order to resolve the important question of the fraction of CII emission that arises in ionized gas. Specifically, we will (1) utilize the fact that due to its ionization potential NII is found only in HII regions, and with PACS 122 and 205 micron observations, determine electron densities in a sample of such regions in the Galactic plane; (2) utilize available data on radio free-free and H-alpha emission to determine the NII column densities and from this the CII column densities in the HII regions; (3) use the electron densities to determine the fraction of CII emission arising in the ionized interstellar medium. These observations will be carried out at 150 of the positions in the Galactic plane observed in [CII] by the GOT-C+ project. We will also carry out HIFI observations of 10 selected positions in the 205 micron line to determine spectral characteristics of the NII emission line, which with CII, CI, and CO profiles already in hand will serve as a further discriminant among the proposed sources of CII emission.

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.

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.

Modeling the Anomalous Microwave Emission with Spinning Nanoparticles: No PAHs Required

NASA Astrophysics Data System (ADS)

Hensley, Brandon S.; Draine, B. T.

2017-02-01

In light of recent observational results indicating an apparent lack of correlation between the anomalous microwave emission (AME) and mid-infrared emission from polycyclic aromatic hydrocarbons, we assess whether rotational emission from spinning silicate and/or iron nanoparticles could account for the observed AME without violating observational constraints on interstellar abundances, ultraviolet extinction, and infrared emission. By modifying the SpDust code to compute the rotational emission from these grains, we find that nanosilicate grains could account for the entirety of the observed AME, whereas iron grains could be responsible for only a fraction, even for extreme assumptions on the amount of interstellar iron concentrated in ultrasmall iron nanoparticles. Given the added complexity of contributions from multiple grain populations to the total spinning dust emission, as well as existing uncertainties due to the poorly constrained grain size, charge, and dipole moment distributions, we discuss generic, carrier-independent predictions of spinning dust theory and observational tests that could help identify the AME carrier(s).

Fugitive coke oven gas emission profile by continuous line averaged open-path Fourier transform infrared monitoring.

PubMed

Lin, Chitsan; Liou, Naiwei; Chang, Pao-Erh; Yang, Jen-Chin; Sun, Endy

2007-04-01

Although most coke oven research is focused on the emission of polycyclic aromatic hydrocarbons, well-known carcinogens, little has been done on the emission of volatile organic compounds, some of which are also thought to be hazardous to workers and the environment. To profile coke oven gas (COG) emissions, we set up an open-path Fourier transform infrared (OP-FTIR) system on top of a battery of coke ovens at a steel mill located in Southern Taiwan and monitored average emissions in a coke processing area for 16.5 hr. Nine COGs were identified, including ammonia, CO, methane, ethane, ethylene, acetylene, propylene, cyclohexane, and O-xylene. Time series plots indicated that the type of pollutants differed over time, suggesting that different emission sources (e.g., coke pushing, quench tower, etc.) were involved at different times over the study period. This observation was confirmed by the low cross-correlation coefficients of the COGs. It was also found that, with the help of meteorological analysis, the data collected by the OP-FTIR system could be analyzed effectively to characterize differences in the location of sources. Although the traditional single-point samplings of emissions involves sampling various sources in a coke processing area at several different times and is a credible profiling of emissions, our findings strongly suggest that they are not nearly as efficient or as cost-effective as the continuous line average method used in this study. This method would make it easier and cheaper for engineers and health risk assessors to identify and to control fugitive volatile organic compound emissions and to improve environmental health.

Far-infrared rotational emission by carbon monoxide

NASA Technical Reports Server (NTRS)

Mckee, C. F.; Storey, J. W. V.; Watson, D. M.; Green, S.

1982-01-01

Accurate theoretical collisional excitation rates are used to determine the emissivities of CO rotational lines for an H2 molecule content of at least 10,000/cu cm, temperature in the range 100-3000 K, and J not more than 60 under the assumption that the lines are optically thin. An approximate analytic expression for the emissivities which is valid in this region is obtained. Population inversions in the lower rotational levels occur for densities of molecular H2 around 1000-100,000/cu cm and temperatures T not more than about 50 K provided photon trapping is unimportant. Interstellar shocks observed edge-on are a potential source of weak millimeter-wave CO maser emission.

Synoptic observations of Jupiter's radio emissions: Average Statistical properties observed by Voyager

NASA Technical Reports Server (NTRS)

Alexander, J. K.; Carr, T. D.; Thieman, J. R.; Schauble, J. J.; Riddle, A. C.

1980-01-01

Observations of Jupiter's low frequency radio emissions collected over one month intervals before and after each Voyager encounter were analyzed. Compilations of occurrence probability, average power flux density and average sense of circular polarization are presented as a function of central meridian longitude, phase of Io, and frequency. The results are compared with ground based observations. The necessary geometrical conditions are preferred polarization sense for Io-related decametric emission observed by Voyager from above both the dayside and nightside hemispheres are found to be essentially the same as are observed in Earth based studies. On the other hand, there is a clear local time dependence in the Io-independent decametric emission. Io appears to have an influence on average flux density of the emission down to below 2 MHz. The average power flux density spectrum of Jupiter's emission has a broad peak near 9MHz. Integration of the average spectrum over all frequencies gives a total radiated power for an isotropic source of 4 x 10 to the 11th power W.

Optical/Infrared properties of Be stars in X-ray Binary systems

NASA Astrophysics Data System (ADS)

Naik, Sachindra

2018-04-01

Be/X-ray binaries, consisting of a Be star and a compact object (neutron star), form the largest subclass of High Mass X-ray Binaries. The orbit of the compact object around the Be star is wide and highly eccentric. Neutron stars in the Be/X-ray binaries are generally quiescent in X-ray emission. Transient X-ray outbursts seen in these objects are thought to be due to the interaction between the compact object and the circumstellar disk of the Be star at the periastron passage. Optical/infrared observations of the companion Be star during these outbursts show that the increase in the X-ray intensity of the neutron star is coupled with the decrease in the optical/infrared flux of the companion star. Apart from the change in optical/infrared flux, dramatic changes in the Be star emission line profiles are also seen during X-ray outbursts. Observational evidences of changes in the emission line profiles and optical/infrared continuum flux along with associated X-ray outbursts from the neutron stars in several Be/X-ray binaries are presented in this paper.

Stars and reionization: the cross-correlation of the 21 cm line and the near-infrared background

NASA Astrophysics Data System (ADS)

Fernandez, Elizabeth R.; Zaroubi, Saleem; Iliev, Ilian T.; Mellema, Garrelt; Jelić, Vibor

2014-05-01

With improving telescopes, it may now be possible to observe the Epoch of Reionization in multiple ways. We examine two of these observables - the excess light in the near-infrared background that may be due to high-redshift stars and ionized HII bubbles, and the 21 cm emission from neutral hydrogen. Because these two forms of emission should result from different, mutually exclusive regions, an anticorrelation should exist between them. We discuss the strengths of using cross-correlations between these observations to learn more about high-redshift star formation and reionization history. In particular, we create simulated maps of emission from both the near-infrared background and 21 cm emission. We find that these observations are anticorrelated, with the strongest anticorrelation originating from times when the universe is half ionized. This result is robust and does not depend on the properties of the stars themselves. Rather, it depends on the ionization history. Cross-correlations can provide redshift information, which the near-infrared background cannot provide alone. In addition, cross-correlations can help separate foreground emission from the true high-redshift component, making it possible to say with greater certainty that we are indeed witnessing the Epoch of Reionization.

Thermal infrared emission spectroscopy of the pyroxene mineral series

NASA Astrophysics Data System (ADS)

Hamilton, Victoria E.

2000-04-01

The thermal infrared emissivity spectra of coarse particulate samples of compositions in the pyroxene series display reststrahlen features (absorptions) that distinguish not only orthorhombic from monoclinic structures, but also major end-members within the two structural groups, as well as minerals within solid solution series. The exact number of reststrahlen features observed and their positions are dependent on mineral structure and cation occupancy of the M1 and M2 sites. End-member quadrilateral pyroxenes (Mg2Si2O6-Fe2Si2O6-Ca[Mg,Fe]Si2O6) are easily distinguished from each other and from minerals in the nonquadrilateral series (NaFeSi2O6-Na[Al,Fe]Si2O6-LiAlSi2O6). Furthermore, among quadrilateral pyroxenes, variations in Mg/(Mg+Fe) are linearly correlated with several band locations, as are variations in Ca content in high-Ca clinopyroxenes. In both quadrilateral and nonquadrilateral compositions, Christiansen feature positions are also diagnostic. No correlations with minor constituents (of the order of 0.05 atoms per formula unit) were observed. The detailed spectral characteristics of pyroxenes and their variability as a function of structure and cation occupancy are presented here with determinative curves for the identification of pyroxene composition. These data have important implications for the interpretation of spectral data from both laboratory and remote sensing instruments because they should permit a more detailed determination of pyroxene composition in measured unknown pure mineral and bulk compositions dominated by surface scattering, i.e., all particulates greater than ~65 μm, and solid samples.

Apparatus and method for transient thermal infrared spectrometry

DOEpatents

McClelland, John F.; Jones, Roger W.

1991-12-03

A method and apparatus for enabling analysis of a material (16, 42) by applying a cooling medium (20, 54) to cool a thin surface layer portion of the material and to transiently generate a temperature differential between the thin surface layer portion and the lower portion of the material sufficient to alter the thermal infrared emission spectrum of the material from the black-body thermal infrared emission spectrum of the material. The altered thermal infrared emission spectrum of the material is detected by a spectrometer/detector (28, 50) while the altered thermal infrared emission spectrum is sufficiently free of self-absorption by the material of the emitted infrared radiation. The detection is effected prior to the temperature differential propagating into the lower portion of the material to an extent such that the altered thermal infrared emission spectrum is no longer sufficiently free of self-absorption by the material of emitted infrared radiation, so that the detected altered thermal infrared emission spectrum is indicative of the characteristics relating to the molecular composition of the material.

High-resolution mid-infrared observations of NGC 7469

NASA Technical Reports Server (NTRS)

Miles, J. W.; Houck, J. R.; Hayward, T. L.

1994-01-01

We present a high-resolution 11.7 micrometer image of the starburst/Seyfert hybrid galaxy NGC 7469 using the Hale 5 m telescope at Palomar Observatory. Our map, with diffraction limited spatial resolution of 0.6 sec, shows a 3 sec diameter ring of emission around an unresolved nucleus. The map is similar to the Very Large Array (VLA) 6 cm map of this galaxy made with 0.4 sec resolution by Wilson et al. (1991). About half of the mid-infrared flux in our map emerges from the unresolved nucleus. We also present spatially resolved low resolution spectra that show that the 11.3 micrometer polycyclic aromatic hydrocarbon (PAH) feature comes from the circumnuclear ring but not from the nucleus of the galaxy.

Constraining CO emission estimates using atmospheric observations

NASA Astrophysics Data System (ADS)

Hooghiemstra, P. B.

2012-06-01

We apply a four-dimensional variational (4D-Var) data assimilation system to optimize carbon monoxide (CO) emissions and to reduce the uncertainty of emission estimates from individual sources using the chemistry transport model TM5. In the first study only a limited amount of surface network observations from the National Oceanic and Atmospheric Administration Earth System Research Laboratory (NOAA/ESRL) Global Monitoring Division (GMD) is used to test the 4D-Var system. Uncertainty reduction up to 60% in yearly emissions is observed over well-constrained regions and the inferred emissions compare well with recent studies for 2004. However, since the observations only constrain total CO emissions, the 4D-Var system has difficulties separating anthropogenic and biogenic sources in particular. The inferred emissions are validated with NOAA aircraft data over North America and the agreement is significantly improved from the prior to posterior simulation. Validation with the Measurements Of Pollution In The Troposphere (MOPITT) instrument shows a slight improved agreement over the well-constrained Northern Hemisphere and in the tropics (except for the African continent). However, the model simulation with posterior emissions underestimates MOPITT CO total columns on the remote Southern Hemisphere (SH) by about 10%. This is caused by a reduction in SH CO sources mainly due to surface stations on the high southern latitudes. In the second study, we compare two global inversions to estimate carbon monoxide (CO) emissions for 2004. Either surface flask observations from NOAA or CO total columns from the MOPITT instrument are assimilated in a 4D-Var framework. In the Southern Hemisphere (SH) three important findings are reported. First, due to their different vertical sensitivity, the stations-only inversion increases SH biomass burning emissions by 108 Tg CO/yr more than the MOPITT-only inversion. Conversely, the MOPITT-only inversion results in SH natural emissions

Mid-Infrared Properties of the Swift Burst Alert Telescope Active Galactic Nuclei Sample of the Local Universe. 1. Emission-Line Diagnostics

DTIC Science & Technology

2010-06-20

reserved. Printed in the U.S.A. MID-INFRARED PROPERTIES OF THE SWIFT BURST ALERT TELESCOPE ACTIVE GALACTIC NUCLEI SAMPLE OF THE LOCAL UNIVERSE . I. EMISSION... the AGNs. We also compare the mid-infrared emission lines in the BAT AGNs with those from published studies of ULIRGs, Palomar- Green quasars, star...supermassive black holes (e.g., Rees 1984; Peterson et al. 2004). One way to approach the study of AGNs is to concentrate on those in the local universe

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

NASA Astrophysics Data System (ADS)

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

2017-09-01

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

Infrared fluorescence from PAHs in the laboratory

NASA Technical Reports Server (NTRS)

Cherchneff, Isabelle; Barker, John R.

1989-01-01

Several celestial objects, including UV rich regions of planetary and reflection nebulae, stars, H II regions, and extragalactic sources, are characterized by the unidentified infrared emission bands (UIR bands). A few years ago, it was proposed that polycyclic aromatic hydrocarbon species (PAHs) are responsible for most of the UIR bands. This hypothesis is based on a spectrum analysis of the observed features. Comparisons of observed IR spectra with lab absorption spectra of PAHs support the PAH hypothesis. An example spectrum is represented, where the Orion Bar 3.3 micron spectrum is compared with the absorption frequencies of the PAHs Chrysene, Pyrene, and Coronene. The laser excited 3.3 micron emission spectrum is presented from a gas phase PAH (azulen). The infrared fluorescence theory (IRF) is briefly explained, followed by a description of the experimental apparatus, a report of the results, and discussion.

PLANE-INTEGRATED OPEN-PATH FOURIER TRANSFORM INFRARED SPECTROMETRY METHODOLOGY FOR ANAEROBIC SWINE LAGOON EMISSION MEASUREMENTS

EPA Science Inventory

Emissions of ammonia and methane from an anaerobic lagoon at a swine animal feeding operation were evaluated five times over a period of two years. The plane-integrated (PI) open-path Fourier transform infrared spectrometry (OP-FTIR) methodology was used to transect the plume at ...

FAST TRACK COMMUNICATION: Emission wavelength extension of mid-infrared InAsSb/InP nanostructures using InGaAsSb sandwich layers

NASA Astrophysics Data System (ADS)

Lei, W.; Tan, H. H.; Jagadish, C.

2010-08-01

This paper presents a study on the emission wavelength extension of InAsSb nanostructures using InGaAsSb sandwich layers. Due to the reduced lattice mismatch between InAsSb nanostructure layer and buffer/capping layer, the introduction of InGaAsSb sandwich layers leads to larger island size, reduced compressive strain and lower confinement barrier for InAsSb nanostructures, thus resulting in a longer emission wavelength. For InGaAsSb sandwich layers with nominal Sb concentration higher than 10%, type II band alignment is observed for the InAsSb/InGaAsSb heterostructure, which also contributes to the extension of emission wavelength. The InGaAsSb sandwich layers provide an effective approach to extend the emission wavelength of InAsSb nanostructures well beyond 2 µm, which is very useful for device applications in the mid-infrared region.

Emission beyond 4  μm and mid-infrared lasing in a dysprosium-doped indium fluoride (InF3) fiber.

PubMed

Majewski, Matthew R; Woodward, Robert I; Carreé, Jean-Yves; Poulain, Samuel; Poulain, Marcel; Jackson, Stuart D

2018-04-15

Optical emission from rare-earth-doped fluoride fibers has thus far been limited to less than 4 μm. We extend emission beyond this limit by employing an indium fluoride (InF 3 ) glass fiber as the host, which exhibits an increased infrared transparency over commonly used zirconium fluoride (ZBLAN). Near-infrared pumping of a dysprosium-doped InF 3 fiber results in broad emission centered around 4.3 μm, representing the longest emission yet achieved from a fluoride fiber. The first laser emission in an InF 3 fiber is also demonstrated from the 3 μm dysprosium transition. Finally, a frequency domain excited state lifetime measurement comparison between fluoride hosts suggests that multiphonon effects are significantly reduced in indium fluoride fiber, paving the way to more efficient, longer wavelength lasers compared to ZBLAN fibers.

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

NASA Technical Reports Server (NTRS)

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

2017-01-01

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

Mid-infrared interferometric variability of DG Tauri: Implications for the inner-disk structure

NASA Astrophysics Data System (ADS)

Varga, J.; Gabányi, K. É.; Ábrahám, P.; Chen, L.; Kóspál, Á.; Menu, J.; Ratzka, Th.; van Boekel, R.; Dullemond, C. P.; Henning, Th.; Jaffe, W.; Juhász, A.; Moór, A.; Mosoni, L.; Sipos, N.

2017-08-01

Context. DG Tau is a low-mass pre-main sequence star, whose strongly accreting protoplanetary disk exhibits a so-far enigmatic behavior: its mid-infrared thermal emission is strongly time-variable, even turning the 10 μm silicate feature from emission to absorption temporarily. Aims: We look for the reason for the spectral variability at high spatial resolution and at multiple epochs. Methods: Infrared interferometry can spatially resolve the thermal emission of the circumstellar disk, also giving information about dust processing. We study the temporal variability of the mid-infrared interferometric signal, observed with the VLTI/MIDI instrument at six epochs between 2011 and 2014. We fit a geometric disk model to the observed interferometric signal to obtain spatial information about the disk. We also model the mid-infrared spectra by template fitting to characterize the profile and time dependence of the silicate emission. We use physically motivated radiative transfer modeling to interpret the mid-infrared interferometric spectra. Results: The inner disk (r < 1-3 au) spectra exhibit a 10 μm absorption feature related to amorphous silicate grains. The outer disk (r > 1-3 au) spectra show a crystalline silicate feature in emission, similar to the spectra of comet Hale-Bopp. The striking difference between the inner and outer disk spectral feature is highly unusual among T Tauri stars. The mid-infrared variability is dominated by the outer disk. The strength of the silicate feature changed by more than a factor of two. Between 2011 and 2014 the half-light radius of the mid-infrared-emitting region decreased from 1.15 to 0.7 au. Conclusions: For the origin of the absorption we discuss four possible explanations: a cold obscuring envelope, an accretion heated inner disk, a temperature inversion on the disk surface and a misaligned inner geometry. The silicate emission in the outer disk can be explained by dusty material high above the disk plane, whose mass can

Mg+ and other metallic emissions observed in the thermosphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, J.A.; Viereck, R.A.; Murad, E.

1994-11-17

Limb observations of UV dayglow emissions from 80 to 300 km tangent heights were made in December 1992, using the GLO instrument, which flew on STS-53 as a Hitchhiker-G experiment. STS-53 was at 330 km altitude and had an orbit inclination of 57 deg. The orbit placed the shuttle near the terminator for the entire mission, resulting in a unique set of observations. The GLO instrument consisted of 12 imagers and 9 spectrographs on an Az/El gimbal system. The data was obtained over 6 days of the mission. Emissions from Mg+ and Ca+ were observed, as were emissions from themore » neutral metallic species Mg and Na. The ultimate source of the metals is ablation of meteors; however, the spatial distribution of the emissions is controlled by upper mesospheric and thermospheric winds and, in the case of the ions, by the electromagnetic fields of the ionosphere. The observed Mg+ emission was the brightest of the metal emissions, and was observed near the poles and around the geomagnetic equator near sunset. The polar emissions were short-lived and intense, indicative of auroral activity. The equatorial emissions were more continuous, with several luminous patches propagation poleward over the period of several orbits. The instrumentation will be described, as will spatial and temporal variations of the metal emissions with emphasis on the metal ions. These observations will be compared to previous observations of thermospheric metallic species.« less

Analysis on energy transfer process of Ho3+ doped fluoroaluminate glass sensitized by Yb3+ for mid-infrared 2.85 μm emission

NASA Astrophysics Data System (ADS)

Zhou, Beier; Wei, Tao; Cai, Muzhi; Tian, Ying; Zhou, Jiajia; Deng, Degang; Xu, Shiqing; Zhang, Junjie

2014-12-01

This work reports the mid-infrared emission properties around 2.85 μm in a Yb3+/Ho3+ codoped fluoroaluminate glass. This fluoroaluminate glass shows a good thermal stability and high transmittance around 3 μm. The mid-infrared emission characteristics and energy transfer mechanism upon the excitation of the conventional 980 nm laser diode have been investigated. The prepared glass possesses higher spontaneous transition probability (31.77 s-1) along with the larger calculated emission cross section (1.91×10-20 cm2) corresponding to the laser transition of Ho3+:5I6→5I7. Besides, the upconversion, 1.2 μm and 2 μm fluorescence spectra were measured to understand mid-infrared emission behavior together with decay curves of Ho3+:5I6 level. Moreover, energy transfer microparameters between Yb3+ and Ho3+ were calculated and discussed based on Dexter's model. Hence, the advantageous spectroscopic characteristics of Yb3+/Ho3+ codoped fluoroaluminate glass as well as the good thermal property indicate that this kind of glass is an attractive host for developing mid-infrared solid state laser.

Derivation of an observation-based map of North African dust emission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evan, Amato T.; Fiedler, Stephanie; Zhao, Chun

Changes in the emission, transport and deposition of aeolian dust have profound effects on regional climate, so that characterizing the lifecycle of dust in observations and improving the representation of dust in global climate models is necessary. A fundamental aspect of characterizing the dust cycle is quantifying surface dust fluxes, yet no spatially explicit estimates of this flux exist for the World’s major source regions. Here we present a novel technique for creating a map of the annual mean emitted dust flux for North Africa based on retrievals of dust storm frequency from the Meteosat Second Generation Spinning Enhanced Visiblemore » and InfraRed Imager (SEVIRI) and the relationship between dust storm frequency and emitted mass flux derived from the output of five models that simulate dust. Our results suggest that 64 (±16)% of all dust emitted from North Africa is from the Bodélé depression, and that 13 (±3)% of the North African dust flux is from a depression lying in the lee of the Aïr and Hoggar Mountains, making this area the second most important region of emission within North Africa.« less

Characterisation of mineral dust emission in the Middle EAST using the Spinning Enhanced Visible and Infrared Imager (SEVIRI)

NASA Astrophysics Data System (ADS)

Hennen, M.; Shahgedanova, M.; White, K.

2015-12-01

Using the Spinning Enhanced Visual and InfraRed Imager (SEVIRI) on-board Meteosat's second generation satellite (MSG), mineral dust emissions from the Middle East were observed at a high temporal and spatial resolution between the years 2006 and 2013. This research provides a subjective derivation of mineral dust source locations in the Middle East using the thermal infrared Dust RGB product. Focusing on the brightness temperature difference around 10.8 µm channel and their spectral contrast with clear sky conditions, the Dust RGB product has been recognised as a major asset in detecting dust. While the product has already been used to map dust emissions in Sahara and south Africa, this research is the first to map dust emissions in the Middle East using SEVIRI, one of the dustiest regions in the world second only to the Sahara Desert. For every dust storm activation within the Middle East, the point of first emission is derived from visual inspection of each 15 minute image, these points were then recorded in a dust source climatology (DSC) database, along with time and direction of dust movement. To take account of potential errors inherent in this subjective detection method, a degree of confidence is associated with each data point with relevance to time of day (which has a strong effect on ability to detect dust in these products) and weather conditions, in particular presence of clouds. These results are compared with an automated retrieval using Aerosol Optical Depth (AOD) measurements form the Moderate Resolution Image Spectrometer (MODIS); which, due to its sun-synchronous orbit allows a measurement of dust in the atmosphere once a day. Differences in the spatial distribution of SEVIRI dust sources and MODIS inferred dust source regions can be explained by inherent transport bias in the latter's low sampling rate and prevailing wind conditions. This database will provide an important tool in further understanding dust emission processes in the region

Nebular Phase Observations of the Type Ia Supernova 2014J in the Near Infrared

NASA Astrophysics Data System (ADS)

Diamond, Tiara

2018-01-01

Late-time spectra of SNe Ia show numerous strong emission features of iron and cobalt throughout the near infrared region. As the spectrum ages, the cobalt features fade as is expected from the decay of 56Co to 56Fe. The strong 1.6440 μm [Fe II] feature is sensitive to the central density of the white dwarf just prior to the runaway because of electron capture in the early stages of burning, hence the line profile width and evolution can be used to probe possible progenitor scenarios. The line profile is dependent on the extent of mixing during any deflagration burning in addition to asymmetries in the distribution of burning products or an off-center ignition. We present observations of SN 2014J from 300–500 days post-explosion. The data are consistent with spherical models of a MCh explosion with a deflagration-to-detonation transition, central density of 0.7×109 g/cm3, and limited mixing. An asymmetry in the line profile of the last spectrum could indicate an off-center ignition or burning products that are not centered on the kinetic center of the explosion. These and other late-time spectroscopic observations in the infrared of a significant sample of SNe Ia will provide insight into the natural variety of these objects, improving our understanding of the underlying physical processes and their usability in cosmology.

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

NASA Astrophysics Data System (ADS)

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

2013-10-01

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

Structure of the Extended Emission in the Infrared Celestial Background,

DTIC Science & Technology

1986-09-30

the energy cascade to smaller sizes due to turbulence. Such a steep function would predict little energy in microfilaments at the resolution of a meter...Neugebauer, H.H. Aumann, N. Boggess, J.P. Emerson, J.R. Fuck , B.T. Soifer and R.G. Walker, "IRAS Observations of the Diffuse Infrared Background", Astrophys. J...Astrcphys., Vol. 100, 116, 1981. " 80. Little , S.J. and S.D. Price, "Infrared Mapping of the Galactic Plane. IV. The Galactic Center", Astron. J., Vol

Fine particulate matter emissions inventories: comparisons of emissions estimates with observations from recent field programs.

PubMed

Simon, Heather; Allen, David T; Wittig, Ann E

2008-02-01

Emissions inventories of fine particulate matter (PM2.5) were compared with estimates of emissions based on data emerging from U.S. Environment Protection Agency Particulate Matter Supersites and other field programs. Six source categories for PM2.5 emissions were reviewed: on-road mobile sources, nonroad mobile sources, cooking, biomass combustion, fugitive dust, and stationary sources. Ammonia emissions from all of the source categories were also examined. Regional emissions inventories of PM in the exhaust from on-road and nonroad sources were generally consistent with ambient observations, though uncertainties in some emission factors were twice as large as the emission factors. In contrast, emissions inventories of road dust were up to an order of magnitude larger than ambient observations, and estimated brake wear and tire dust emissions were half as large as ambient observations in urban areas. Although comprehensive nationwide emissions inventories of PM2.5 from cooking sources and biomass burning are not yet available, observational data in urban areas suggest that cooking sources account for approximately 5-20% of total primary emissions (excluding dust), and biomass burning sources are highly dependent on region. Finally, relatively few observational data were available to assess the accuracy of emission estimates for stationary sources. Overall, the uncertainties in primary emissions for PM2.s are substantial. Similar uncertainties exist for ammonia emissions. Because of these uncertainties, the design of PM2.5 control strategies should be based on inventories that have been refined by a combination of bottom-up and top-down methods.

A Multiwavelength Study of Cygnus X-1: The First Mid-Infrared Spectroscopic Detection of Compact Jets

NASA Technical Reports Server (NTRS)

Rahoui, Farid; Lee, Julia C.; Heinz, Sebastian; Hines, Dean C.; Pottschmidt, Katja; Wilms, Joern

2011-01-01

We report on a Spitzer/IRS (mid-infrared), RXTE /PCA+HEXTE (X-ray), and Ryle (radio) simultaneous multi-wavelength study of the micro quasar Cygnus X-I, which aimed at an investigation of the origin of its mid-infrared emission. Compact jets were present in two out of three observations, and we show that they strongly contribute to the mid-infrared continuum. During the first observation, we detect the spectral break - where the transition from the optically thick to the optically thin regime takes place - at about 2.9 x 10(exp 13) Hz. We then show that the jet's optically thin synchrotron emission accounts for the Cygnus X-1's emission beyond 400 keY, although it cannot alone explain its 3-200 keV continuum. A compact jet was also present during the second observation, but we do not detect the break, since it has likely shifted to higher frequencies. In contrast, the compact jet was absent during the last observation, and we show that the 5-30 micron mid-infrared continuum of Cygnus X-I stems from the blue supergiant companion star HD 226868. Indeed, the emission can then be understood as the combination of the photospheric Raleigh-Jeans tail and the bremsstrahlung from the expanding stellar wind. Moreover, the stellar wind is found to be clumpy, with a filling factor f(sub infinity) approx.= 0.09-0.10. Its bremsstrahlung emission is likely anti-correlated to the soft X-ray emission, suggesting an anticorrelation between the mass-loss and mass-accretion rates. Nevertheless, we do not detect any mid-infrared spectroscopic evidence of interaction between the jets and the Cygnus X-1's environment and/or companion star's stellar wind.

Global CO emission estimates inferred from assimilation of MOPITT and IASI CO data, together with observations of O3, NO2, HNO3, and HCHO.

NASA Astrophysics Data System (ADS)

Zhang, X.; Jones, D. B. A.; Keller, M.; Jiang, Z.; Bourassa, A. E.; Degenstein, D. A.; Clerbaux, C.; Pierre-Francois, C.

2017-12-01

Atmospheric carbon monoxide (CO) emissions estimated from inverse modeling analyses exhibit large uncertainties, due, in part, to discrepancies in the tropospheric chemistry in atmospheric models. We attempt to reduce the uncertainties in CO emission estimates by constraining the modeled abundance of ozone (O3), nitrogen dioxide (NO2), nitric acid (HNO3), and formaldehyde (HCHO), which are constituents that play a key role in tropospheric chemistry. Using the GEOS-Chem four-dimensional variational (4D-Var) data assimilation system, we estimate CO emissions by assimilating observations of CO from the Measurement of Pollution In the Troposphere (MOPITT) and the Infrared Atmospheric Sounding Interferometer (IASI), together with observations of O3 from the Optical Spectrograph and InfraRed Imager System (OSIRIS) and IASI, NO2 and HCHO from the Ozone Monitoring Instrument (OMI), and HNO3 from the Microwave Limb Sounder (MLS). Our experiments evaluate the inferred CO emission estimates from major anthropogenic, biomass burning and biogenic sources. Moreover, we also infer surface emissions of nitrogen oxides (NOx = NO + NO2) and isoprene. Our results reveal that this multiple species chemical data assimilation produces a chemical consistent state that effectively adjusts the CO-O3-OH coupling in the model. The O3-induced changes in OH are particularly large in the tropics. Overall, our analysis results in a better constrained tropospheric chemical state.

X-ray Counterparts of Infrared Faint Radio Sources

NASA Astrophysics Data System (ADS)

Schartel, Norbert

2011-10-01

Infrared Faint Radio Sources (IFRS) are radio sources with extremely faint or even absent infrared emission in deep Spitzer Surveys. Models of their spectral energy distributions, the ratios of radio to infrared flux densities and their steep radio spectra strongly suggest that IFRS are AGN at high redshifts (2observe 8 IFRS using 30ks pointed observations. X-ray detections of IFRS with different ratios of radio-to-infrared fluxes, will constrain the class-specific SED.

Infrared emission spectra from operating elastohydrodynamic sliding contacts

NASA Technical Reports Server (NTRS)

Lauer, J. L.

1976-01-01

Infrared emission spectra from an operating EHD sliding contact were obtained through a diamond window for an aromatic polymer solute present in equal concentration in four different fluids. Three different temperature ranges, three different loads, and three different speeds for every load were examined. Very sensitive Fourier spectrophotometric (Interferometric) techniques were employed. Band Intensities and band intensity ratios found to depend both on the operating parameters and on the fluid. Fluid film and metal surface temperatures were calculated from the spectra and their dependence on the mechanical parameters plotted. The difference between these temperatures could be plotted against shear rate on one curve for all fluids. However, at the same shear rate the difference between bulk fluid temperature and diamond window temperature was much higher for one of the fluids, a traction fluid, than for the others.

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

NASA Technical Reports Server (NTRS)

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

Observation of runaway electrons by infrared camera in J-TEXT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tong, R. H.; Chen, Z. Y., E-mail: zychen@hust.edu.cn; Zhang, M.

2016-11-15

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

Detecting volcanic SO2 emissions with the Infrared Atmospheric Sounding Interferometer

NASA Astrophysics Data System (ADS)

Taylor, Isabelle; Carboni, Elisa; Mather, Tamsin; Grainger, Don

2017-04-01

Sulphur dioxide (SO2) emissions are one of the many hazards associated with volcanic activity. Close to the volcano they have negative impacts on human and animal health and affect the environment. Further afield they present a hazard to aviation (as well as being a proxy for volcanic ash) and can cause global changes to climate. These are all good reasons for monitoring gas emissions at volcanoes and this monitoring can also provide insight into volcanic, magmatic and geothermal processes. Advances in satellite technology mean that it is now possible to monitor these emissions from space. The Infrared Atmospheric Sounding Interferometer (IASI) on board the European Space Agency's MetOp satellites is commonly used, alongside other satellite products, for detecting SO2 emissions across the globe. A fast linear retrieval developed in Oxford separates the signal of the target species (SO2) from the spectral background by representing background variability (determined from pixels containing no SO2) in a background covariance matrix. SO2 contaminated pixels can be distinguished from this quickly, facilitating the use of this algorithm for near real time monitoring and for scanning of large datasets for signals to explore further with a full retrieval. In this study, the retrieval has been applied across the globe to identify volcanic emissions. Elevated signals are identified at numerous volcanoes including both explosive and passive emissions, which match reports of activity from other sources. Elevated signals are also evident from anthropogenic activity. These results imply that this tool could be successfully used to identify and monitor activity across the globe.

HST observations of Europa's atmospheric UV emission

NASA Astrophysics Data System (ADS)

Saur, J. S.; Feldman, P. D.; Strobel, D. F.; Retherford, K. D.; Roth, L.; McGrath, M. A.; Gerard, J. M.; Grodent, D. C.; Schilling, N.

2009-12-01

The Advanced Camera for Surveys on the Hubble Space Telescope observed Europa on June 29, 2008 during five consecutive orbits. Europa was at eastern elongation and crossed the Jovian current sheet during the observing interval. The observations were performed with ACS/SBC with prism PR130L to separate the two prominent FUV oxygen lines OI 1304 A, OI 1356 A and to discriminate reflected solar light from Europa's surface. After addressing the strong red leak contained in the measurements, we find that Europa's atmospheric emission clearly depends on Europa's position in Jupiter's current sheet. We also see that the atmospheric emissions of Europa's leading side do not show pronounced asymmetries with respect to Europa's sub-Jovian and anti-Jovian side. Previous observations of the atmospheric emissions, in contrast, found a strong asymmetry on Europa's trailing side [McGrath et al. 2004].

Quantifying emissions of CO and NOx using observations from MOPITT, OMI, TES, and OSIRIS

NASA Astrophysics Data System (ADS)

Zhang, X.; Jones, D. B. A.; Keller, M.; Walker, T. W.; Jiang, Z.; Henze, D. K.; Bourassa, A. E.; Degenstein, D. A.; Rochon, Y. J.

2016-12-01

We use the GEOS-Chem four-dimensional variational (4D-var) data assimilation with satellite observations of multiple chemical species to estimate emissions of CO and NOx, as well as the tropospheric concentrations of O3. In doing so, we utilize CO retrievals from The Measurements of Pollution In The Troposphere (MOPITT), O3 retrievals from the Tropospheric Emission Spectrometer (TES), O3 retrievals from the Optical Spectrograph and InfraRed Imager System (OSIRIS), and NO2 columns from the Ozone Monitoring Instrument (OMI). By integrating these data in the 4D-Var scheme, we obtain a chemical state in the model that is consistent with all of the data over the assimilation period. In this context, for example, we find that combining TES and OSIRIS improves O3, particularly in the tropical upper troposphere (by 10-20%), which leads to a reduction in the uncertainty of the NOx emission estimates. However, although assimilating multiple chemical species provides a stronger constraint on the chemical, state, there are still large uncertainties on the CO and NOx emission estimates, due to the dependence of the results on the selection of the assimilation window and how the datasets are weighted in the cost function.

Lower-tropospheric CO 2 from near-infrared ACOS-GOSAT observations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kulawik, Susan S.; O'Dell, Chris; Payne, Vivienne H.

We present two new products from near-infrared Greenhouse Gases Observing Satellite (GOSAT) observations: lowermost tropospheric (LMT, from 0 to 2.5 km) and upper tropospheric–stratospheric ( U, above 2.5 km) carbon dioxide partial column mixing ratios. We compare these new products to aircraft profiles and remote surface flask measurements and find that the seasonal and year-to-year variations in the new partial column mixing ratios significantly improve upon the Atmospheric CO 2 Observations from Space (ACOS) and GOSAT (ACOS-GOSAT) initial guess and/or a priori, with distinct patterns in the LMT and U seasonal cycles that match validation data. For land monthly averages,more » we find errors of 1.9, 0.7, and 0.8 ppm for retrieved GOSAT LMT, U, and XCO 2; for ocean monthly averages, we find errors of 0.7, 0.5, and 0.5 ppm for retrieved GOSAT LMT, U, and XCO 2. In the southern hemispheric biomass burning season, the new partial columns show similar patterns to MODIS fire maps and MOPITT multispectral CO for both vertical levels, despite a flat ACOS-GOSAT prior, and a CO–CO 2 emission factor comparable to published values. The difference of LMT and U, useful for evaluation of model transport error, has also been validated with a monthly average error of 0.8 (1.4) ppm for ocean (land). LMT is more locally influenced than U, meaning that local fluxes can now be better separated from CO 2 transported from far away.« less

Lower-tropospheric CO 2 from near-infrared ACOS-GOSAT observations

DOE PAGES

Kulawik, Susan S.; O'Dell, Chris; Payne, Vivienne H.; ...

2017-04-27

We present two new products from near-infrared Greenhouse Gases Observing Satellite (GOSAT) observations: lowermost tropospheric (LMT, from 0 to 2.5 km) and upper tropospheric–stratospheric ( U, above 2.5 km) carbon dioxide partial column mixing ratios. We compare these new products to aircraft profiles and remote surface flask measurements and find that the seasonal and year-to-year variations in the new partial column mixing ratios significantly improve upon the Atmospheric CO 2 Observations from Space (ACOS) and GOSAT (ACOS-GOSAT) initial guess and/or a priori, with distinct patterns in the LMT and U seasonal cycles that match validation data. For land monthly averages,more » we find errors of 1.9, 0.7, and 0.8 ppm for retrieved GOSAT LMT, U, and XCO 2; for ocean monthly averages, we find errors of 0.7, 0.5, and 0.5 ppm for retrieved GOSAT LMT, U, and XCO 2. In the southern hemispheric biomass burning season, the new partial columns show similar patterns to MODIS fire maps and MOPITT multispectral CO for both vertical levels, despite a flat ACOS-GOSAT prior, and a CO–CO 2 emission factor comparable to published values. The difference of LMT and U, useful for evaluation of model transport error, has also been validated with a monthly average error of 0.8 (1.4) ppm for ocean (land). LMT is more locally influenced than U, meaning that local fluxes can now be better separated from CO 2 transported from far away.« less

Widespread SiO and CH3OH emission in filamentary infrared dark clouds

NASA Astrophysics Data System (ADS)

Cosentino, G.; Jiménez-Serra, I.; Henshaw, J. D.; Caselli, P.; Viti, S.; Barnes, A. T.; Fontani, F.; Tan, J. C.; Pon, A.

2018-03-01

Infrared dark clouds (IRDCs) are cold, dense regions of high (optical and infrared) extinction, believed to be the birthplace of high-mass stars and stellar clusters. The physical mechanisms leading to the formation of these IRDCs are not completely understood and it is thus important to study their molecular gas kinematics and chemical content to search for any signature of the IRDCs formation process. Using the 30-m-diameter antenna at the Instituto de Radioastronomía Milimétrica (IRAM), we have obtained emission maps of dense gas tracers (H13CO+ and HN13C) and typical shock tracers (SiO and CH3OH) towards three IRDCs, G028.37+00.07, G034.43+00.24, and G034.77-00.55 (clouds C, F, and G, respectively). We have studied the molecular gas kinematics in these clouds and, consistent with previous works towards other IRDCs, the clouds show complex gas kinematics with several velocity-coherent substructures separated in velocity space by a few km s-1. Correlated with these complex kinematic structures, widespread (parsec-scale) emission of SiO and CH3OH is present in all the three clouds. For clouds C and F, known to be actively forming stars, widespread SiO and CH3OH is likely associated with on-going star formation activity. However, for cloud G, which lacks either 8 or 24 μm sources and 4.5 μm H2 shock-excited emission, the detected widespread SiO and CH3OH emission may have originated in a large-scale shock interaction, although a scenario involving a population of low-mass stars driving molecular outflows cannot be fully ruled out.

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.

Remote optical observations of actively burning biomass fires using potassium line spectral emission

NASA Astrophysics Data System (ADS)

Magidimisha, Edwin; Griffith, Derek J.

2016-02-01

Wildland fires are a widespread, seasonal and largely man-made hazard which have a broad range of negative effects. These wildfires cause not only the destruction of homes, infrastructure, cultivated forests and natural habitats but also contribute to climate change through greenhouse gas emissions and aerosol particle production. Global satellite-based monitoring of biomass burning using thermal infrared sensors is currently a powerful tool to assist in finding ways to establish suppression strategies and to understand the role that fires play in global climate change. Advances in silicon-based camera technology present opportunities to resolve the challenge of ubiquitous wildfire early detection in a cost-effective manner. This study investigated several feasibility aspects of detecting wildland fires using near-infrared (NIR) spectral line emissions from electronically excited potassium (K) atoms at wavelengths of 766.5 and 769.9 nm, during biomass burning.

The nature of extreme emission line galaxies at z = 1-2: kinematics and metallicities from near-infrared spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maseda, Michael V.; Van der Wel, Arjen; Rix, Hans-Walter

2014-08-10

We present near-infrared spectroscopy of a sample of 22 Extreme Emission Line Galaxies at redshifts 1.3 < z < 2.3, confirming that these are low-mass (M{sub *} = 10{sup 8}-10{sup 9} M{sub ☉}) galaxies undergoing intense starburst episodes (M{sub *}/SFR ∼ 10-100 Myr). The sample is selected by [O III] or Hα emission line flux and equivalent width using near-infrared grism spectroscopy from the 3D-HST survey. High-resolution NIR spectroscopy is obtained with LBT/LUCI and VLT/X-SHOOTER. The [O III]/Hβ line ratio is high (≳ 5) and [N II]/Hα is always significantly below unity, which suggests a low gas-phase metallicity. We aremore » able to determine gas-phase metallicities for seven of our objects using various strong-line methods, with values in the range 0.05-0.30 Z{sub ☉} and with a median of 0.15 Z{sub ☉}; for three of these objects we detect [O III] λ4363, which allows for a direct constraint on the metallicity. The velocity dispersion, as measured from the nebular emission lines, is typically ∼50 km s{sup –1}. Combined with the observed star-forming activity, the Jeans and Toomre stability criteria imply that the gas fraction must be large (f{sub gas} ≳ 2/3), consistent with the difference between our dynamical and stellar mass estimates. The implied gas depletion timescale (several hundred Myr) is substantially longer than the inferred mass-weighted ages (∼50 Myr), which further supports the emerging picture that most stars in low-mass galaxies form in short, intense bursts of star formation.« less

Ethylene line emission from the North Pole of Jupiter

NASA Technical Reports Server (NTRS)

Kostiuk, Theodor; Espenak, F.; Romani, P.; Goldstein, J.

1991-01-01

A significant enhancement in infrared emission from hydrocarbon constituents of Jupiter's stratosphere was observed at a north polar hot spot (60 degrees latitude, 180 degrees longitude). A unique probe of this phenomena is ethylene (C2H4), which has not been observed previously from the ground. The profile of the emission line from ethylene at 951.742 cm-1, measured near the north pole of Jupiter, was analyzed to determine the morphology of the enhancement, the increase in C2H4 abundance and local temperature, as well as possible information on the altitude (pressure regions) where the increased emission is formed. Measurements were made using infrared heterodyne spectroscopy at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii in December 1989. At 181 degrees longitude a very strong emission line was seen, which corresponds to a 13-fold increase in C2H4 abundance or a 115K increase in temperature in the upper stratosphere, compared to values outside the hot spot. The hot spot was found to be localized to approx. 10 degrees in longitude; the line shape (width) implied that the enhanced emission originated very high in the stratosphere.

JIRAM infrared observations of Jupiter Aurorae: results of the first year.

NASA Astrophysics Data System (ADS)

Mura, A.; Adriani, A.; Altieri, F.; Dinelli, B. M.; Moriconi, M. L.; Migliorini, A.; Bolton, S. J.; Connerney, J. E. P.; Cicchetti, A.; Noschese, R.; Sindoni, G.; Tosi, F.; Filacchione, G.; Fabiano, F.; Piccioni, G.; Turrini, D.; Amoroso, M.; Plainaki, C.; Olivieri, A.; Gerard, J.-C.

2017-09-01

JIRAM (Jovian Infrared Auroral Mapper) is an imaging spectrometer on board the Juno spacecraft, specifically designed to observe the aurorae of Jupiter. Here we show results on JIRAM's data after one year of observations. The footprints of Io, Europa and Ganymede have also been observed and characterized.

IRAS observations of NGC 1052

NASA Technical Reports Server (NTRS)

Neugebauer, G.; Soifer, B. T.; Rice, W.; Rowan-Robinson, M.

1984-01-01

The galaxy NGC 1052 has been observed with the IRAS satellite. The infrared emission at 100 microns is substantially larger than a smooth extrapolation of the radio data. Because of the large diaphragm size of IRAS, it is impossible to decide uniquely if the infrared radiation represents a self-absorbed nonthermal spectrum or thermal reradiation by heated dust.

Small-scale structure of the CO emission in S255 from lunar occultation observations

NASA Technical Reports Server (NTRS)

Schloerb, F. P.; Scoville, N. Z.

1980-01-01

Two lunar occultations of the S255 H II region/molecular cloud complex were observed in the 2.6 mm CO line during 1978 and 1979. The resolution obtained (between 4 arcsec and 7 arcsec) enables us to resolve bright sources that are much smaller than the 44 arcsec telescope beam. In addition to the large-scale structure (approximately 10 arcmin in size) seen in previous CO maps, the observations reveal two high-temperature emission regions in the cloud core associated with two compact infrared sources about 20 arcsec apart. The first CO hot spot is larger in size with a Gaussian width of 41 arcsec + or - 7 arcsec and a peak temperature of 65 K. Its center falls between the two small infrared sources S255 IRS1 and IRS2. The linear size and peak temperature of this source are remarkably similar to those in the Orion Kleinmann-Low nebula. The second source is revealed from a discontinuous change in the CO line flux as the lunar limb crossed S255 IRS1. The size of this component is less than 7 arcsec; its temperature must exceed 200 K. No evidence is found for exceptionally high temperatures at the boundary of the two H II regions crossed during the occultations.

Conceptual design and structural analysis of the spectroscopy of the atmosphere using far infrared emission (SAFIRE) instrument

NASA Technical Reports Server (NTRS)

Moses, Robert W.; Averill, Robert D.

1992-01-01

The conceptual design and structural analysis for the Spectroscopy of the Atmosphere using Far Infrared Emission (SAFIRE) Instrument are provided. SAFIRE, which is an international effort, is proposed for the Earth Observing Systems (EOS) program for atmospheric ozone studies. A concept was developed which meets mission requirements and is the product of numerous parametric studies and design/analysis iterations. Stiffness, thermal stability, and weight constraints led to a graphite/epoxy composite design for the optical bench and supporting struts. The structural configuration was determined by considering various mounting arrangements of the optical, cryo, and electronic components. Quasi-static, thermal, modal, and dynamic response analyses were performed, and the results are presented for the selected configuration.

CINE: Comet INfrared Excitation

NASA Astrophysics Data System (ADS)

de Val-Borro, Miguel; Cordiner, Martin A.; Milam, Stefanie N.; Charnley, Steven B.

2017-08-01

CINE calculates infrared pumping efficiencies that can be applied to the most common molecules found in cometary comae such as water, hydrogen cyanide or methanol. One of the main mechanisms for molecular excitation in comets is the fluorescence by the solar radiation followed by radiative decay to the ground vibrational state. This command-line tool calculates the effective pumping rates for rotational levels in the ground vibrational state scaled by the heliocentric distance of the comet. Fluorescence coefficients are useful for modeling rotational emission lines observed in cometary spectra at sub-millimeter wavelengths. Combined with computational methods to solve the radiative transfer equations based, e.g., on the Monte Carlo algorithm, this model can retrieve production rates and rotational temperatures from the observed emission spectrum.

An alternative mechanism for production of emission features in some infrared objects

NASA Technical Reports Server (NTRS)

Apruzese, J. P.

1975-01-01

Two dust-envelope models of the M supergiant VX Sgr, which exhibits a prominent emission feature at 10 microns, are presented. The models indicate that, for certain envelope sizes, the presence of the observed emission feature does not necessarily indicate that the emitting grains possess a similar feature in their emissivity profile. The mechanism which may in some cases be producing the observed emission feature is discussed.

The infrared and optical variability of OJ 287

NASA Astrophysics Data System (ADS)

Fan, J. H.; Adam, G.; Xie, G. Z.; Cao, S. L.; Lin, R. G.; Qin, Y. P.; Copin, Y.; Bai, J. M.; Zhang, X.; Li, K. H.

1998-12-01

In this paper, the long-term historical optical (UBVRI) and near-infrared (JHK) data are presented with some new observations in the optical (February 1994-January 1995) and near-infrared (November 1995) bands included for BL Lac object OJ 287. The new optical data in V-band are in agreement with the results reported by other authors (Sillanpaa et al. 1996a; Arimoto et al. 1997), a close correlation between the color index of B-V and the magnitude V has been obtained from our new observations. The new infrared observations presented here indicate that the source was at a high level in the infrared band during the observation period. From the available literature, we have got that the largest variations for UBVRIJHK bands are respectively: Delta U = 4fm 72; Delta B = 5fm 93; Delta V = 5fm 18; Delta R = 4fm 45 ; Delta I = 4fm 07; Delta J = 3fm 87 ; Delta H = 3fm 78; Delta K = 3fm 54 . A strong correlation is found between the optical and near-infrared bands when the DCF method is used, which suggests that these two bands have the same emission mechanism.

A High Spatial Resolution Study of Far IR Emission of Galaxies

NASA Technical Reports Server (NTRS)

Caldwell, Barrie A.

2000-01-01

This grant funded observations, data reduction, professional publications and travel for scientific efforts on the Kuiper Airborne Observatory. The research project was successfully completed. New insights into the distribution of far infrared emission across star forming regions was obtained, and student training was achieved. The efforts contributed towards new observing strategies, such as calibration and intercomparison of data from different infrared astronomical observing platforms, that will impact future NASA missions, such as SOFIA. The results of the effort have been presented in several papers in the refereed literature, including: "The Structure of IR Luminous Galaxies at 100 Microns". " Far Infrared Thermal Emission from the Inner Cooling Flow Region of NGC1275". "Distribution of Light in the "Dusty Hand" Galaxy NGC2146".

On the Determination of the Emission Wavelength of an Infrared LED with Common Laboratory Instruments

ERIC Educational Resources Information Center

RayChaudhuri, Barun

2011-01-01

This work demonstrates an experiment on the optoelectronic properties of a p-n junction suitable for students of undergraduate physics. It investigates, from an educational point of view, the origin of the wavelength of radiation emitted by a light emitting diode (LED) and determines the emission wavelength of an infrared LED without using…

Aeolian system dynamics derived from thermal infrared data

NASA Astrophysics Data System (ADS)

Scheidt, Stephen Paul

Thermal infrared (TIR) remote-sensing and field-based observations were used to study aeolian systems, specifically sand transport pathways, dust emission sources and Saharan atmospheric dust. A method was developed for generating seamless and radiometrically accurate mosaics of thermal infrared data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument. Using a combination of high resolution thermal emission spectroscopy results of sand samples and mosaic satellite data, surface emissivity was derived to map surface composition, which led to improvement in the understanding of sand accumulation in the Gran Desierto of northern Sonora, Mexico. These methods were also used to map sand transport pathways in the Sahara Desert, where the interaction between sand saltation and dust emission sources was explored. The characteristics and dynamics of dust sources were studied at White Sands, NM and in the Sahara Desert. At White Sands, an application was developed for studying the response of dust sources to surface soil moisture based on the relationship between soil moisture, apparent thermal inertia and the erosion potential of dust sources. The dynamics of dust sources and the interaction with sand transport pathways were also studied, focusing on the Bodele Depression of Chad and large dust sources in Mali and Mauritania. A dust detection algorithm was developed using ASTER data, and the spectral emissivity of observed atmospheric dust was related to the dust source area in the Sahara. At the Atmospheric Observatory (IZO) in Tenerife, Spain where direct measurement of the Saharan Air Layer could be made, the cycle of dust events occurring in July 2009 were examined. From the observation tower at the IZO, measurements of emitted longwave atmospheric radiance in the TIR wavelength region were made using a Forward Looking Infrared Radiometer (FLIR) handheld camera. The use of the FLIR to study atmospheric dust from the Saharan is a

The Nature of Deeply Buried Ultraluminous Infrared Galaxies: A Unified Model for Highly Obscured Dusty Galaxy Emission

NASA Astrophysics Data System (ADS)

Marshall, J. A.; Elitzur, M.; Armus, L.; Diaz-Santos, T.; Charmandaris, V.

2018-05-01

We present models of deeply buried ultraluminous infrared galaxy (ULIRG) spectral energy distributions (SEDs) and use them to construct a three-dimensional diagram for diagnosing the nature of observed ULIRGs. Our goal is to construct a suite of SEDs for a very simple model ULIRG structure, and to explore how well this simple model can (by itself) explain the full range of observed ULIRG properties. We use our diagnostic to analyze archival Spitzer Space Telescope Infrared Spectrograph data of ULIRGs and find that: (1) in general, our model does provide a comprehensive explanation of the distribution of mid-IR ULIRG properties; (2) >75% (in some cases 100%) of the bolometric luminosities of the most deeply buried ULIRGs must be powered by a dust-enshrouded active galactic nucleus; (3) an unobscured “keyhole” view through ≲10% of the obscuring medium surrounding a deeply buried ULIRG is sufficient to make it appear nearly unobscured in the mid-IR; (4) the observed absence of deeply buried ULIRGs with large polycyclic aromatic hydrocarbon (PAH) equivalent widths is naturally explained by our models, showing that deep absorption features are “filled-in” by small quantities of foreground unobscured PAH emission (e.g., from the host galaxy disk) at the level of ∼1% the bolometric nuclear luminosity. The modeling and analysis we present will also serve as a powerful tool for interpreting the high angular resolution spectra of high-redshift sources to be obtained with the James Webb Space Telescope.

Observation of SO2 degassing at Stromboli volcano using a hyperspectral thermal infrared imager

NASA Astrophysics Data System (ADS)

Smekens, Jean-François; Gouhier, Mathieu

2018-05-01

Thermal infrared (TIR) imaging is a common tool for the monitoring of volcanic activity. Broadband cameras with increasing sampling frequency give great insight into the physical processes taking place during effusive and explosive event, while Fourier transform infrared (FTIR) methods provide high resolution spectral information used to assess the composition of volcanic gases but are often limited to a single point of interest. Continuing developments in detector technology have given rise to a new class of hyperspectral imagers combining the advantages of both approaches. In this work, we present the results of our observations of volcanic activity at Stromboli volcano with a ground-based imager, the Telops Hyper-Cam LW, when used to detect emissions of sulfur dioxide (SO2) produced at the vent, with data acquired at Stromboli volcano (Italy) in early October of 2015. We have developed an innovative technique based on a curve-fitting algorithm to quickly extract spectral information from high-resolution datasets, allowing fast and reliable identification of SO2. We show in particular that weak SO2 emissions, such as inter-eruptive gas puffing, can be easily detected using this technology, even with poor weather conditions during acquisition (e.g., high relative humidity, presence of fog and/or ash). Then, artificially reducing the spectral resolution of the instrument, we recreated a variety of commonly used multispectral configurations to examine the efficiency of four qualitative SO2 indicators based on simple Brightness Temperature Difference (BTD). Our results show that quickly changing conditions at the vent - including but not limited to the presence of summit fog - render the establishment of meaningful thresholds for BTD indicators difficult. Building on those results, we propose recommendations on the use of multispectral imaging for SO2 monitoring and routine measurements from ground-based instruments.

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

NASA Technical Reports Server (NTRS)

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

2017-01-01

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

Infrared images of merging galaxies

NASA Technical Reports Server (NTRS)

Wright, G. S.; James, P. A.; Joseph, R. D.; Mclean, I. S.; Doyon, R.

1990-01-01