2009/08/20 by Lisa H. Wei, Sheila J. Kannappan, Wei, Lisa H. +7
Chemistry · Physics and Astronomy · #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Spectroscopy and Laser Applications #astro-ph.CO
paper · pdf · doi:10.48550/arxiv.0908.2868
4 pages, 3 figures, to be published in the Proceedings of the `Galaxy Wars: Stellar Populations and Star Formation in Interacting Galaxies Conference'
arxiv created 2009/08/20 · arxiv updated 2009/12/01
We examine the HI+H2 content of blue-sequence E/S0s -- a recently identified population of galaxies that are morphologically early type, but reside alongside spiral galaxies in color vs. stellar mass space. We test the idea that the majority of low-to-intermediate mass blue-sequence E/S0s may be settled products of past mergers evolving toward later-type morphology via disk regrowth. We find that blue-sequence E/S0s with stellar masses <= 4 x 1010 M\odot have atomic gas-to-stellar mass ratios of 0.1 to > 1.0, comparable to those of spiral galaxies. Preliminary CO(1-0) maps reveal disk-like rotation of molecular gas in the inner regions of several of our blue-sequence E/S0s, which suggests that they may have gas disks suitable for stellar disk regrowth. At the current rate of star formation, many of our blue-sequence E/S0s will exhaust their atomic gas reservoirs in <~ 3 Gyr. Over the same time period, most of these galaxies are capable of substantial growth in the stellar component. Star formation in blue-sequence E/S0s appears to be bursty, and likely involves inflow triggered by minor mergers and/or interactions.