M17SW giant cold H I cloud

Abstract

view Abstract Citations (5) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS M17SW Giant Cold HI Cloud Sato, Fumio ; Whiteoak, John B. ; Otrupcek, Robina E. ; Tokushige, Tetsuya Abstract The M17SW giant molecular cloud (GMC) is mapped in the 21-cm absorption line with the Parkes 64-m telescope. The cold H I cloud in the region has a total extent of over 120 pc and consists of three major fragments with different ages. The main part of the youngest fragment has not been found in CO lines, but it is probably bound gravitationally with an H2 density of about 80/cu cm. Such diffuse molecular gas in the cold H I cloud nearly doubles the total mass previously estimated in the M17SW GMC from molecular line observations. The three H I fragments are arranged in order of decreasing age in the direction of passage of a shock associated with the galactic density wave. This suggests that the galactic shock plays an important role in cloud formation in the region. Publication: The Astronomical Journal Pub Date: May 1992 DOI: 10.1086/116176 Bibcode: 1992AJ....103.1627S Keywords: Gas Density; H I Regions; Molecular Clouds; Absorption Spectra; Astronomical Spectroscopy; Carbon Monoxide; Spectral Line Width; Astrophysics; RADIO LINES: MOLECULAR: INTERSTELLAR; ISM: MOLECULES full text sources ADS | data products SIMBAD (7)