Observations of HI in dense interstellar dust clouds: II. The cloud Khavtassi 3

Abstract

view Abstract Citations (17) References (22) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observations of HI in dense interstellar dust clouds: II. The cloud Khavtassi 3 Knapp, G. R. Abstract High-frequency-resolution Hi observations of the dark cloud Khavtassi 3 show that the Hi in the cloud, seen as a narrow self-absorption component at + 13 km/sec, correlates well in position with the darkest parts of the cloud. The Hi column density is highest where the dust is darkest, which implies that the Hi is distributed throughout the cloud. Simple models of the Hi distribution in the cloud, combined with the absorption profile for the continuum source W44, which is behind Kh 3, show that the neutral atomic hydrogen in this cloud is less than 1% of the total hydrogen content of the cloud. Several other self-absorption features were found in the observations, corresponding to Hi clouds at different velocities and distances along the line of sight. An HI cloud at + 30 km/sec was mapped; in this cloud the relative abundance of HI is considerably higher than it is in the + 13 km/sec cloud. Other clouds at velocities of +7, +22, +38, +45, +55, and +81 km/sec were also found. Several of these clouds have a patchy structure. The cloud at +45 km/sec (the velocity of W44) forms a ring around W44. Publication: The Astronomical Journal Pub Date: May 1974 DOI: 10.1086/111575 Bibcode: 1974AJ.....79..541K full text sources ADS | Related Materials (1) Part 1: 1974AJ.....79..527K