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NASA NTRS1980

Cataloged infrared sources in NIPSS data. I - The RSO 1 catalog

A small number of selected near-infrared and visual photographic pairs from the Steward Observatory Near Infrared Photographic Sky Survey have been examined for content of stars more red than (V-I) of about 2.5 magnitudes. A simple manual extraction of these objects was carried out as a part of a preliminary evaluation of survey data and techniques for reducing it; the resulting list has been compiled as the first installment of a Catalog of Red Stellar Objects (Craine et al. 1979). Results of a cross correlation of this catalog with the IRC, AFGL, and EIC infrared catalogs are here presented. The results indicate that these photographs may be particularly useful for purposes of optical identification of short-wavelength infrared sources to limits much fainter than represented by presently existing infrared catalogs.

Horner, V. M.↗

NASA NTRS1980

Infrared observations of the galactic nucleus

Infrared observations of the galactic nucleus and conclusions regarding the nature of the objects present there are reviewed. Observations of three sources of infrared radiation are discussed: near-infrared emission from cool stars, mid- and far-infrared emission from dust, and line emission from ionized gas. These observations provide information about the mass distribution, the stellar population, and the origin and ionization of the compact mid-infrared sources. The possibility of the existence of a massive central black hole is discussed.

Lacy, J. H.↗

NASA NTRS1981

Infrared studies of the S235 molecular cloud

Infrared observations from 7.8 to 200 microns have been obtained for the S235 molecular cloud. Far-infrared maps were obtained for a region of active star formation, as marked by the presence of compact H II regions, water masers, and compact near-infrared sources. The primary heating source for the far-infrared emission appears to be the compact H II region, S235A. Detailed examination of the gas energetics in the region supports the plausibility of the picture in which the gas is heated by collisions with warm dust grains. The ratio of far-infrared optical depth to (C-13)O column density is somewhat lower in this source than is commonly found. This effect may be caused by the presence of substantial (C-13)O in regions where the dust is not warm enough to emit substantial 50-100 micron radiation.

Evans, N. J., II↗

NASA NTRS1981

An extended far-infrared emission complex at IC 1318b and IC 1318c

A map of extended 90 micron emission with 15 arcmin resolution is presented for sources centered on IC 1318b and c. A strong correlation is found between far-infrared emission and radio continuum emission, although a comparison of far-infrared and CO molecular line maps shows no similarity. Extended far-infrared sources have inferred gas densities, which implies that far-infrared emitting dust is mixed with the ionized gas. Far-infrared emission from dust is also observed in the nonthermal radio source DR 4 which is part of a supernova remnant, and the data are compatible with a core-halo model for the compact source DR 7.

Campbell, M. F.↗

NASA NTRS1981

Infrared fiber optic focal plane dispersers

Far infrared transmissive fiber optics as a component in the design of integrated far infrared focal plane array utilization is discussed. A tightly packed bundle of fibers is placed at the focal plane, where an array of infrared detectors would normally reside, and then fanned out in two or three dimensions to individual detectors. Subsequently, the detectors are multiplexed by cryogenic electronics for relay of the data. A second possible application is frequency up-conversion (v sub 1 + v sub 2 = v sub 3), which takes advantage of the nonlinear optical index of refraction of certain infrared transmissive materials in fiber form. Again, a fiber bundle is utilized as above, but now a laser of frequency v sub 1 is mixed with the incoming radiation of frequency v sub 1 within the nonlinear fiber material. The sum, v sub 2 is then detected by near infrared or visible detectors which are more sensitive than those available at v sub 2. Due to the geometrical size limitations of detectors such as photomultipliers, the focal plane dispersal technique is advantageous for imaging up-conversion.

Goebel, J. H.↗

NASA NTRS1982

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

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

Jaffe, D. T.↗

NASA NTRS1982

Space infrared astronomy - Overview of NASA planning

The present status and potential future direction of the NASA space infrared astronomy program is reviewed. Projects and project concepts discussed include the Infrared Astronomy Satellite, Small Infrared Telescope on Spacelab 2, Cosmic Background Explorer, Shuttle Infrared Telescope Facility, Space Telescope, large deployable reflector, molecular line survey, and infrared interferometer in space. Needs for continued engineering development in critical technology areas such as detectors, cryogenics, optics, and space structures are indicated.

Hauser, M. G.↗

NASA NTRS1981

Passive optical and infrared meteorology

Applications of passive visible and infrared techniques to the study of meteorological parameters are presented. For the remote sensing of temperature and humidity profiles, infrared sounder improvements have proceeded with the narrow band-pass channels approach, and the partially scanned interferogram approach. Current and planned infrared and microwave sea-surface temperature sounders have an expected accuracy of approximately 2 K, and this can be improved by using three super window channels from the 3.7 micron window region, with narrow band passes away from principal water vapor absorption lines. Cloud data remote sensing is currently performed from satellites, and these visible and infrared images have been used to track weather patterns. In addition, a passive infrared correlation-spectroscopy technique has been proposed for wind measurements. Finally, these techniques have also been applied to monitor such parameters as the Solar Constant, aerosols, and minor gas constituents.

Chahine, M. T.↗

NASA NTRS1982

Visual and infrared observations of the distant Comets P/Stephan-Oterma /1980g/, Panther /1980u/, and Bowell /1980b/

The paper reports combined visual imagery and spectroscopy, near-infrared spectroscopy, and broadband infrared photometry of comets P/Stephan-Oterma (1980g), Bowell (1980b), and Panther (1980u) at intermediate heliocentric distances. The visual data indicate the existence of solid grains in extended halos around the nuclei of the three comets. Broadband near-infrared and thermal infrared measurements of Comet Panther suggest the presence of 2-4-micron-radius particles in the coma which most likely contain molecules incorporating the N-H bond, but which are more complex and less volatile than NH3. Such molecules can be produced in the grains by cosmic-ray reprocessing. Near infrared spectral features identical to those seen in comet Panther similary suggest the presence of a molecule incorporating the N-H bond in comet Bowell.

Jewitt, D. C.↗

NASA NTRS1983

X-ray, radio, and infrared observations of the 'rapid burster' /MXB 1730-335/ during 1979 and 1980

The paper reports partially simultaneous observations of the 'rapid burster' (MXB 1730-335) at X-ray, infrared, and radio wavelengths, covering several hundred hours during 1979 and 1980. None of the authors of this report saw any infrared or radio bursts. On several occasions an absence of infrared bursting was observed during X-ray bursting. On one occasion an absence of X-ray bursting was observed during a radio burst (4.1 GHz) reported by Calla et al. (1979). To date, radio bursts (a total of at least a dozen) have been reported only by Calla et al. (1980). Considering these and other observations summarized here, the reported radio bursts are either unreal or do not bear a simple relation to the X-ray bursts from the 'rapid burster'. The status of the reported infrared bursts also remain ambiguous. Limits to the brightness of any persistent radio source at the position of MXB 1730-335, limits to persistent X-ray emission during an extended X-ray quiet phase, and a measurement of the infrared polarization in the direction of the X-ray source are also reported.

Lawrence, A.↗

NASA NTRS1983

Infrared observations of RS CVn stars

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

Berriman, G.↗

NASA NTRS1984

Infrared observations of galactic bulge X-ray sources

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

Hertz, P.↗

NASA NTRS1985

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

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

Wilking, B. A.↗

NASA NTRS1985

Infrared variability of SS 433

New JHKLM photometry of SS 433 showing short time scale variabilities is reported for the period of 1983 July 16-22 UT. The entire body of infrared data included in this paper, Giles et al. (1980), and Catchpole et al. (1981), is examined with reference to periods of 164 days and 13.08 days. Comparison of the infrared light curves with the optical light curves of Leibowitz et al. (1984) makes it possible to conclude, within the context of an accretion disk model, that the majority of the infrared flux in the SS 433 system comes from the disk, and that the hot spot responsible for the 'hump' in the visual and infrared light curves has a color similar to the average of the disk. A two-dimensional Fourier analysis of the infrared data suggests that the brightness maximum occurs when, seen from the compact star, the noncompact companion passes through a fixed elongation relative to the disk line of nodes with the orbital plane, if the precession is prograde.

Kodaira, K.↗

NASA NTRS1986

An infrared reflection nebula surrounding SGS 1 in the NGC 1333 dark cloud

Strom et al. (1974) have conducted a search for infrared sources associated with Herbig-Haro objects. They found an infrared source, SGS 1, near HH 12, embedded in at least 20 visual mag of extinction in the NGC 1333 dark cloud. Various factors suggest the presence of an infrared reflection nebula. In the context of the present investigation, high spatial resolution observations in the infrared have provided the basis for the development of a consistent model for SGS which consists of a low-luminosity, cool star with an accretion disk tilted to the line of sight, and one observed reflection lobe caused by the illumination of material above one of the polar regions of the accretion disk. It is pointed out that this model is similar to that of the infrared reflection nebula GSS 30 in the Ophiuchus dark cloud.

Castelaz, M. W.↗

NASA NTRS1986

Infrared studies of the Herbig-Haro object 1-2 region

Far-infrared (50-100 micrometers) photometric mapping and near-infrared spectroscopic mapping of the Herbig-Haro 1-2 region are presented. Both lobes of the double-lobed far-infrared source in this region are found to be nearly coincident with recently discovered radio continuum sources. The dust temperature structure around each peak is not spherically symmetric, suggesting either that the far-infrared sources are centrally heated or that the dust column density is highly nonspherically symmetric. The results are consistent with a picture in which each far-infrared lobe contains a highly obscured young star surrounded by a highly nonspherically symmetric dust cloud. A complementary study by Strom et al. (1985) is pointed out.

Harvey, P. M.↗

NASA NTRS1986

Infrared reflection nebulae in Orion molecular cloud 2

New obervations of Orion Molecular Cloud-2 have been made from 1-100 microns using the NASA Infrared Telescope Facility and the Kuiper Airborne Observatory. An extensive program of polarimetry, photometry and spectrophotometry has shown that the extended emission regions associated with two of the previously known near infrared sources, IRS1 and IRS4, are infrared reflection nebulae, and that the compact sources IRS1 and IRS4 are the main luminosity sources in the cloud. The constraints from the far infrared observations and an analysis of the scattered light from the IRS1 nebula show that OMC-2/IRS1 can be characterized by L less than or equal to 500 Solar luminosities and T approx. 1000 K. The near infrared (1-5) micron albedo of the grains in the IRS1 nebula is greater than 0.08.

Pendleton, Y.↗

NASA NTRS1986

Far-infrared investigation of the Taurus star-forming region using the IRAS database

The Infrared Astronomical Satellite (IRAS) has given us the first completely unbiased sky-survey in the far-infrared with wavebands centered at 12, 25, 60 and 100 microns. The Taurus-Auriga complex was selected as the first molecular cloud to be investigated in this study. The Taurus clouds were defined as lying between 04h and 05h in R.A. and +16 to +31 degrees in Dec., then the IRAS point-source catalogue was searched for sources with good or moderate quality fluxes in all three of the shortest IRAS bands. The sources which were selected in this way were then classified into subgroups according to their IRAS colors. Taurus is generally believed to be an area of low-mass star formation, having no luminous O-B associations within or near to the cloud complex. Once field stars, galaxies and planetary nebulae had been removed from the sample only the molecular cloud cores, T Tauri stars and a few emission-line A and B stars remained. The great majority of these objects are pre-main sequence in nature and, as stated by Chester (1985), main sequence stars without excess far-infrared emission would only be seen in Taurus if their spectral types were earlier than about A5 and then not 25 microns. By choosing our sample in this way we are naturally selecting the hotter and thus more evolved sources. To counteract this, the molecular cloud core-criterion was applied to soruces with good or moderate quality flux at 25, 60 and 100 microns, increasing the core sample by about one third. The candidate protostar B335 is only detected by IRAS at 60 and 100 microns while Taurus is heavily contaminated by cirrus at 100 microns. This means that detection at 25 microns is also required with those at 60 and 100 microns to avoid confusing a ridge of cirrus with a genuine protostar. The far-infrared luminosity function of these sources is then calculated and converted to the visual band by a standard method to compare with the field star luminosity function of Miller and Scalo. The eventual aim of this work is to obtain far-infrared luminosity functions for a number of molecular clouds which are known to be forming low-mass stars and to investigate how the slope is affected by changes in the density and turbulence of material.

Hughes, J. D.↗