  Recent work suggests blue ellipticals form in mergers and migrate quickly
from the blue cloud of star-forming galaxies to the red sequence of passively
evolving galaxies, perhaps as a result of black hole feedback. Such rapid
reddening of stellar populations implies that large gas reservoirs in the
pre-merger star-forming pair must be depleted on short time scales. Here we
present pilot observations of atomic hydrogen gas in four blue early-type
galaxies that reveal increasing spatial offsets between the gas reservoirs and
the stellar components of the galaxies, with advancing post-starburst age.
Emission line spectra show associated nuclear activity in two of the merged
galaxies, and in one case radio lobes aligned with the displaced gas reservoir.
These early results suggest that a kinetic process (possibly feedback from
black hole activity) is driving the quick truncation of star formation in these
systems, rather than a simple exhaustion of gas supply.
