Giant molecular clouds in the Galaxy. I - The axisymmetric distribution of H2

Abstract

view Abstract Citations (547) References (58) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Giant molecular clouds in the Galaxy. I - The axisymmetric distribution of H2 Sanders, D. B. ; Solomon, P. M. ; Scoville, N. Z. Abstract A two-dimensional (l, b) survey of molecular clouds in the Galaxy is presented. Observations of CO (J = 1→0) emission at over 2500 positions between l = -4° and 170° are interpreted to determine the distribution of molecules at galactic radius, R, from 0 to 16 kpc. The radial distribution of CO surface brightness ICO, exhibits a sharp maximum in the central 1.5 kpc, a minimum at R = 1.5 - 3.5 kpc, and a ring peaking at 6 kpc. Between 6 and 15 kpc, ICO falls by two orders of magnitude, while 21 cm measurements show virtually constant H I surface density. The conversion of ICO to H2 mass is discussed. All empirical measures of this conversion factor agree to better than a factor of 2. The H2 density and surface density are presented as a function of R and z out to R = 16 kpc and compared with the H I densities. The total surface density of interstellar gas (H2 + H I) as function of R is derived from these data. In particular, a detailed discussion of the distribution of interstellar gas in the galactic center region is presented. Publication: The Astrophysical Journal Pub Date: January 1984 DOI: 10.1086/161602 Bibcode: 1984ApJ...276..182S Keywords: Carbon Monoxide; Hydrogen; Interstellar Gas; Mass Distribution; Milky Way Galaxy; Molecular Clouds; Disk Galaxies; Early Stars; Galactic Rotation; Gravitational Collapse; Spectrum Analysis; Stellar Evolution; Astrophysics full text sources ADS |