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Stacey, G. J.

Publications and source records attributed to Stacey, G. J..

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NASA NTRS1985

Observations of far-infrared transitions between excited states of OH

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

Viscuso, P. J.↗
NASA NTRS1985

Submillimeter observations of OH and CH in M42

The 2Pi(1/2) J = 3/2 to 1/2 transitions of OH at 163.12 and 163.40 microns have been detected, and upper limits have been obtained for the 2Pi(3/2) J = 3/2 to 1/2 transitions of CH at 149.09 and 149.39 microns, in observations of the Kleinmann-Low nebula of Orion. The results indicate emission from a gas cloud at a temperature of roughly 1000 K, having thickness of roughly 5 x 10 to the 14th cm with density about 7 million/cu cm and OH abundance of roughly 12 x 10 to the -6th. The OH column density is about 4 x 10 to the 16th/cu cm in the emitting regions. Optical depth effects play a major role in determining the relative strengths of the observed lines.

Viscuso, P. J.↗
NASA NTRS1985

Observation of far-infrared transitions between excited states of OH

Spectra of the Kleinmann-Low nebula in Orion detected the 84.42 and 84.60 micron transitions between the 2Pi(3/2) J = 7/2 and 2Pi(3/2) J = 5/2 levels of OH with respective fluxes of 1 x 10 to the -17th and 1.4 x 10 to the -17th W/sq cm. When compared to the 119 micron flux levels of OH discussed by Watson (1982) and the 163 micron flux levels of OH by Viscuso et al. (1985), these results suggest appreciable self-absorption of OH line radiation within the nebula. The CO emission due to the J = 31 to 30 rotational transition at 84.411 microns makes a substantial contribution to the observed 84.22 micron flux, and is probably at least partially absorbed at the 84.42 micron OH transition frequency.

Viscuso, P. J.↗
NASA NTRS1985

The 157-micron forbidden C II luminosity of the Galaxy. II - The presence of knotlike features in the forbidden C II emission

The measurement by Stacey et al. (1983) of the diffuse 157-micron emission of singly ionized carbon from the Galactic plane is augmented by measurements at two additional galactic longitudes. The results indicate that the total forbidden C II flux from the Galaxy is about 6 x 10 to the 7th solar luminosity - a factor of 8 lower than the previous estimate. It is likely that the measurement at l(II) = 8.0 deg was due to a knot in the forbidden C II emission. The results indicate that the forbidden C II flux has a half width of roughly 0.34 deg, in agreement with the (C-12)O (J = 1-0) half widths. The forbidden C II emission probably arises in at the edges of molecular clouds.

Stacey, G. J.↗
NASA NTRS1985

Far-infrared line emission from the galaxy

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.

Stacey, G. J.↗
NASA NTRS1985

Diffuse 157-micron C II forbidden-line emission from the Galaxy

The diffuse 157.74-micron C II forbidden-line emission from the Galaxy was sampled at several longitudes near the galactic plane including complete scans across the plane at l(II) = 2.16 deg and l(II) = 7.28 deg. The observed C II forbidden-line profiles closely follow the nearby C-12O (J = 1-0) emission profiles. The C II forbidden-line emission probably arises in neutral photodissociation regions near the edges of giant molecular clouds. The total C II forbidden-line luminosity of the Galaxy is 6 x 10 to the 7th solar luminosities. It is estimated that the C II forbidden-line emitting regions consist of 4 x 10 to the 8th solar masses of hydrogen with a volume filling factor of 0.001.

Stacey, G. J.↗
NASA NTRS1984

The 157 Micron (C II) Luminosity of the Galaxy

The diffuse far infrared (C II) emission of several regions of the Galactic plane were sampled. Mechanisms for the excitation of carbon ions are discussed in reference to the role of carbon ion transitions in cooling diffuse atomic hydrogen. Observations indicate that the C II emission probably arises at the edges of giant molecular clouds and appears to have localized knot-like features. The total C II luminosity of the Galaxy is approximately 6 to 10 to the 7th power L(solar).

Stacey, G. J.↗
NASA NTRS1983

Observations of the 145.5 micron O I forbidden emission line in the Orion Nebula

A first set of observations of the forbidden O I 3P0-3P1 (145.5 micron) transition has been obtained. The line was observed both in a 1 x 1 arcmin beam centered on the Trapezium and in a 7 x 7 arcmin beam encompassing most of the Orion Nebula; a wide-beam (7 x 7 arcmin) map of the region has also been constructed which shows that most of the emission is confined to the central regions of the nebula. These observations are consistent with optically thin emission in the 145.5 micron line and self-absorbed 63.2 micron emission lines. Mechanisms for the excitation of neutral oxygen are considered, and it is concluded that much of the observed emission originates in the thin radio recombination line-emitting C II/H I envelope bordering on the H II region.

Stacey, G. J.↗
NASA NTRS1983

Highly ejected J = 16 to 15 rotational transitions of CO at 162.8 mirons in the Orion cloud

The first observations of the J = 16 to J = 15, 162.8 microns transition of CO from an astronomical source are reported. Measurements were carried out on the Kleinmann-Low Nebula. The intensity observed is in good agreement with predictions from previous spectroscopic work carried out in the far infrared. The observation strengthens the previous claim that approximately 1.5 solar mass of molecular hydrogen is heated to a temperature above 750 K within the shocked region in the Nebula. Upper limits to he OH intensity in the F2 (2Pi 1/2) transitions J = 3/2 to J = 1/2 which fall into two groups centered respectively at 163.12 and 163.40 are presented.

Stacey, G. J.↗
NASA NTRS1982

Observations of the 145.5 micron (OI) emission line in the Orion nebula

A first set of observations of the (OI) 3P to 3P1 (145.5 micron) transition was obtained. The line was observed both in a beam centered on the Trapezium, and in a 7 times wider beam encompassing most of the Orion Nebula. A wide beam map of the region was constructed which shows that most of the emission is confined to the central regions of the nebula. These observations may be compared with reported measurement of the 3P1 to 3P2 (63.2 micron) transition in Orion and are consistent with optically thin emission in the 145.5 micron line and self-adsorbed 63.2 micron emission lines. Mechanisms are discussed for the excitation of neutral oxygen. It is included that much of the observed emission originates in the thin, radio-recombination-line-emitting CII/HI envelope bordering on the HII region.

Stacey, G. J.↗
NASA NTRS1982

The mass of hot, shocked CO in Orion - First observations of the J = 17-J = 16 transition at 153 microns

Observations of the Kleinmann-Low Nebula in Orion detected the J = 17-J = 16 transition of CO at 153 microns and at a flux level of 7 x 10 to the -17th W/sq cm. The total mass of hot (not less than about 750 K) carbon monoxide in the nebula is estimated at 8 x 10 to the 30th g, and the total hydrogen mass at this temperature is assessed to be about 1.5 solar masses. A CO column density of about 4 x 10 to the 17th per sq cm is derived for the region, which agrees with those predictions made by Storey et al. (1981), and an apparent deficit of oxygen in the nebula is discussed.

Stacey, G. J.↗