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Werner, M. W.

Publications and source records attributed to Werner, M. W..

143 records · Page 8
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NASA NTRS1976

Far-infrared observations of IRC + 10216

Broadband photometric observations of IRC + 10216 in five wavelength intervals from 50 to 1000 microns are reported. The observed radiation is interpreted as thermal emission from dust in the extended molecular cloud heated by the compact 2-20-micron source at the cloud core. The shape of the 50-1000-micron spectrum suggests that the emissivity of the dust particles varies approximately as the inverse wavelength over this spectral interval. The mass of dust inferred from the far-infrared emission is comparable with the mass of heavy molecules in the cloud.

Campbell, M. P.↗
NASA NTRS1976

Infrared studies of an ionization front region in the Orion Nebula

A ridge or bar of emission at 10 microns has been found which is parallel and adjacent to the H I-H II interface in the Orion Nebula 2 arcmin southeast of the Trapezium. The emission is interpreted as coming from heated dust whose density at the interface is an order of magnitude higher than that inside the H II region. The source of luminosity for this emission is shown to be the Trapezium stars. The unique geometry of the bar with respect to the heat source is used to evaluate the dust density in the bar and the size of the dust grains.

Becklin, E. E.↗
NASA NTRS1976

Support of the infrared radiometer on the ST

The aim was to obtain practical experience, including observational experience, with bolometers suitable for the long wave infrared and with the filters necessary to define the spectral regions of interest. The techniques used in fabricating and testing bolometers and filters are described, and the results which were obtained to date are discussed.

Neugebauer, G.↗
NASA NTRS1976

One arc-minute resolution maps of the Orion Nebula at 20, 50, and 100 microns

The paper presents maps of the central regions of the Orion Nebula which are based on observations made at wavelengths of 20, 50, and 100 microns with a resolution of 1 arcmin. The 50- and 100-micron observations were made with the NASA 91-cm Airborne Infrared Telescope. The principal far-IR features observed include a sharp emission peak near the position of the IR cluster, about 1 arcmin northwest of the Trapezium; a ridge of emission that is elongated north-south about this peak; and a barlike feature running northeast to southwest about 2 arcmin southeast of the Trapezium. The following conclusions are reached about the nature of the far-IR emission: (1) the total luminosity (between 10 and 1000 microns) of the IR cluster exceeds the solar luminosity by a factor of at least 120,000; (2) heating by both the IR cluster and the Trapezium stars is important in producing the central emission ridge; (3) the IR cluster is located within the molecular cloud; (4) the Trapezium stars are no more than 0.1 pc from that cloud; and (5) the bar of emission southeast of the Trapezium can be identified with an optically visible ionization front.

Werner, M. W.↗
NASA NTRS1975

Observations of 1-millimeter continuum radiation from the DR 21 region

Continuum emission at 1 mm has been mapped with 1-min resolution over a 3-min by 8-min area including the compact H II region DR 21, the maser source W75(S)-OH, and the central portions of the surrounding molecular cloud. Peaks in the 1-mm intensity are observed at the positions of DR 21 and W75(S)-OH, and are roughly coincident with less marked peaks in the intensity of HCN and CO emission. An extended component of 1-mm emission is present as well. The principal source of 1-mm radiation is thought to be thermal emission from dust within the molecular gas. The characteristics of this radiation which make it a promising tool for the study of molecular clouds are briefly discussed.

Werner, M. W.↗
NASA NTRS1974

Infrared observations of Comet Kohoutek /1973f/

Comet Kohoutek has been observed at wavelengths between 1.25 and 12.5 microns before and after perihelion passage extending to comet-sun distances of 1 AU. The luminosity and the variation of brightness with comet-sun distance in the infrared are extraordinarily similar to those of Comet Ikeya-Seki (1965f). Apart from an apparent 'silicate' emission feature near 10 microns, the spectrum of the comet between 3.5 and 12.5 microns is close to that expected from emission by grey particles. Hotter particles and scattered sunlight produce the bulk of the 1.25- to 3.5-micron emission.

Gatley, I.↗
NASA NTRS1974

1-millimeter continuum radiation from Orion Molecular Cloud 2

The 1-mm continuum flux from Orion Molecular Cloud 2 (OMC-2), measured with a 1-inch beam, is found to be 0.05 plus or minus 0.01 of that from the Becklin-Neugebauer/Kleinmann-Low (BN/KL) complex. This implies that the average density of dust within OMC-2 is about an order of magnitude less than within the BN/KL region.

Werner, M. W.↗
NASA NTRS1974

Accurate positions of OH sources

The Owens Valley interferometer was used at 1665, 1667, and 1720 MHz to measure the positions of eleven OH emission sources. The 1720-MHz OH source in W3 (continuum) was found to be 40 seconds away from the H2O maser source and was found not to coincide with any radio or infrared feature. Two OH emission sources were found in NGC 7538; one is identifiable with a very compact radio infrared source, while the other, 80 seconds to the south, is as yet unidentified. The OH sources 0739-14 and Sharpless 269 also coincide with infrared sources.

Wynn-Williams, C. G.↗
NASA NTRS1973

Interpretation of far infra-red emission from interstellar grains

Application of the Kramers-Kronig relations to grains in the interstellar medium. It is found that the recent UV, visual, and infrared extinction curves provide marginal evidence against silicates as the major cause of this extinction. In the far infrared, grains contribute little to the extinction, but can be observed in thermal emission. It is shown that the far infrared emission from grains in a given bandwidth sets a lower limit to the grain temperature. From observed intensities from the galactic plane at 100 microns and from Orion at 350 microns, minimum grain temperatures are found which are larger than the observed brightness temperature. The emission and extinction data can be used together to constrain the allowable range of parameters for the grains.

Caroff, L. J.↗
NASA NTRS1972

Interstellar scattering and the sizes of astronomical masers.

The suggestion is explored that scattering by inhomogeneities in the distribution of electrons causes astronomical masers to appear larger than their actual sizes. It is shown that neither scattering near the source nor scattering in the intervening medium is sufficiently strong to produce this effect.

Boyd, R. W.↗
NASA NTRS1971

A search for spectral features in the submillimeter background radiation.

Mountaintop observations were made at 1 per cent spectral resolution of atmospheric and sky emission in an attempt to determine the spectral features of submillimeter background radiation. No emission features were found that could be related to the diffuse isotropic flux reported from rocket and balloon experiments.

Mather, J. C.↗