2006/10/27 by Hiroyuki Nakanishi, Nario Kuno, Yoshiaki Sofue +8 · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Galaxy #Interstellar medium #Metallicity #Ram pressure #Spiral (railway) #Spiral galaxy #Telescope #Virgo Cluster #astro-ph
paper · pdf · doi:10.1086/507974
published as Astrophys.J.651:804-810,2006 · 12 pages, 8 figures. To appear in ApJ
arxiv created 2006/10/27 · openalex publication_date 2006/11/02 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We found high molecular fractions ( f mol ; ratio of the molecular to total gas surface densities) in three of five Virgo spiral galaxies in spite of their low total gas column density, based on 12 CO J = 1-0 observations with the Nobeyama 45 m telescope equipped with a multibeam receiver, BEARS. We interpret this as a result of environmental effects. Combining the CO data with H I data, the relationship between the surface density of the total gas (H I plus H 2 ) and f mol indicates that the three galaxies near the cluster center have larger f mol values than expected for field galaxies, while the others show normal f mol . The large f mol is interpreted as being due either to effective H I gas stripping, even in the inner disks, or to large ISM pressure induced by the high ICM pressure and/or ram pressure, although the possibility of an unusually high metallicity cannot be ruled out.