Is there molecular gas in the H I cloud between NGC 4472 and UGC 7636?
dc.contributor.author | Irwin, JA | |
dc.contributor.author | Frayer, DT | |
dc.contributor.author | Sarazin, CL | |
dc.contributor.other | University of Toronto | |
dc.contributor.other | University of Alabama Tuscaloosa | |
dc.date.accessioned | 2018-09-21T20:08:25Z | |
dc.date.available | 2018-09-21T20:08:25Z | |
dc.date.issued | 1997-05 | |
dc.description.abstract | We present CO observations of the H I cloud located between the Virgo elliptical galaxy NGC 4472 and its dwarf irregular companion galaxy UGC 7636. ROSAT observations of the X-ray halo of NGC 4472 show a hole in the X-ray emission at the position of the H I cloud (Irwin gi Sarazin 1996), If the hole is assumed to be the result of soft X-ray absorption by some absorbing material within the cloud, the total implied mass of the absorbing material is much larger than the measured H I mass of the cloud, This implies that a large fraction of the cloud is composed of molecular hydrogen. However, the CO observations fail to find the required amount of molecular gas if a Galactic CO-to-H-2 conversion factor is assumed. While a low density in the molecular gas might increase the CO-to-H-2 conversion factor enough to make the CO upper limit consistent with the X-ray absorption prediction too low a density would allow the H-2 to be dissociated by UV radiation. We conclude that it is unlikely that the required absorbing mass is present. In any case, these observations provide a strict upper limit on the CO content of the H I cloud. (C) 1997 American Astronomical Society. | en_US |
dc.format.mimetype | application/pdf | |
dc.identifier.citation | Irwin, J., Frayer, D., Sarazin, C. (1997): Is There Molecular Gas in the H 1 Cloud Between NGC 4472 and UGC 7636? The Astronomical Journal, 113(5). DOI: 10.1086/118375 | |
dc.identifier.doi | 10.1086/118375 | |
dc.identifier.uri | http://ir.ua.edu/handle/123456789/3929 | |
dc.language | English | |
dc.language.iso | en_US | |
dc.publisher | American Institute of Physics | |
dc.subject | GIANT ELLIPTIC GALAXY | |
dc.subject | NGC-4472 | |
dc.subject | UGC-7636 | |
dc.subject | MODELS | |
dc.subject | Astronomy & Astrophysics | |
dc.title | Is there molecular gas in the H I cloud between NGC 4472 and UGC 7636? | en_US |
dc.type | text | |
dc.type | Article |
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