Submillimeter and far-infrared line observations of M17 SW - a clumpy molecular cloud penetrated by ultraviolet radiation

Journal Article · Thu Sep 01 04:00:00 EDT 1988 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/166663· OSTI ID:6684117

Stutzki, J; Genzel, R; Harris, A I; Stacey, G J; Jaffe, D T

Millimeter, submillimeter, and far-IR spectroscopic observations of the M17 SW star formation region are reported. Strong forbidden C II 158 micron and CO J = 7 - 6 line emission arises in an H II region/molecular cloud interface of several pc thickness. Weaker forbidden C II emission appears to be extended over 15 pc throughout the molecular cloud. CO J = 14 - 13 and forbidden O I 145 micron spectra indicate high temperatures and densities for both molecular and atomic gas in the interface. The results require the molecular cloud near the interface to be clumpy or filamentary. The extended forbidden C II emission throughout the molecular cloud has a level around 20 times higher than expected from a single molecular cloud interface exposed to an ultraviolet radiation field typical of the solar neighborhood. The high gas temperature of molecular material in the UV-illuminated interface region suggests that CO self-shielding and heating of CO by photoelectrons are important. 70 references.

• Research Organization: Max-Planck-Institut fuer Physik und Astrophysik, Garching (Germany, F.R.); California Univ., Berkeley (USA); Texas Univ., Austin (USA)
• OSTI ID: 6684117
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 332; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COSMIC GASES
COSMIC RADIO SOURCES
DENSITY
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
FAR INFRARED RADIATION
FLUIDS
GASES
H2 REGIONS
HEATING
INFRARED RADIATION
INTERSTELLAR SPACE
MOLECULES
NEBULAE
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIATIONS
SPACE
SPECTRA
STAR EVOLUTION
ULTRAVIOLET RADIATION