Astronomy and Astrophysics – Astronomy
Scientific paper
May 1997
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997aj....113.1580i&link_type=abstract
Astronomical Journal v.113, p. 1580-1584 (1997)
Astronomy and Astrophysics
Astronomy
6
Scientific paper
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 & 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.
Frayer David T.
Irwin Jimmy A.
Sarazin Craig L.
No associations
LandOfFree
Is There Molecular Gas in the HI Cloud Between NGC 4472 and UGC 7636? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Is There Molecular Gas in the HI Cloud Between NGC 4472 and UGC 7636?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Is There Molecular Gas in the HI Cloud Between NGC 4472 and UGC 7636? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-835686