Cold Gas in Blue-Sequence E/S0s: Galaxies in Transition
  We examine the HI+H_2 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 10^10
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.
