[16.01] What the Gaseous Properties of Galaxies in Loose Groups tell us about their Formation

AAS 206th Meeting, 29 May - 2 June 2005
Session 16 Galaxy Surveys
Oral, Monday, 10:00-11:30am, May 30, 2005, 102 E

[16.01] What the Gaseous Properties of Galaxies in Loose Groups tell us about their Formation

D.J. Pisano (Naval Research Laboratory), D.G. Barnes (University of Melbourne), B.K. Gibson (Swinburne University), L. Staveley-Smith (ATNF), K.C. Freeman (RSAA), V.A. Kilborn (Swinburne University)

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 analogs to the high-velocity clouds (HVCs) within these groups down to M_HI< 10⁷M_sun as a test of models of galaxy formation. We show that the HI mass function and halo mass function of the loose groups are consistent with those of the Local Group, and that, therefore, the Local Group is not an atypical loose group. 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. This research was performed while the author held a National Research Council Research Associateship Award at the Naval Research Laboratory.

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