What Do Loose Groups Tell Us about Galaxy Formation?
D. J. Pisano
We present the results of our HI survey of six loose groups of
galaxies analogous to the Local Group. The survey was conducted using the
Parkes telescope and the Australia Telescope Compact Array to produce a
census of all the gas-rich galaxies and potential analogs to the
high-velocity clouds (HVCs) within these groups down to M(HI) < 107
M(sun) as a test of models of galaxy formation. We present the HI mass
function and halo mass function for these analogous groups and compare
them with the Local Group and other environments. We also demonstrate
that our non-detection of HVC analogs in these groups implies that they
must have low HI masses and be clustered tightly around galaxies,
including around our own Milky Way, and are not distributed throughout the
Local Group.