EAS Publications Series
Volume 56, 2012The Role of the Disk-Halo Interaction in Galaxy Evolution: Outflow vs. Infall?
|Page(s)||275 - 279|
|Section||The Active Disk-Halo Connection: Infall vs. Outflows|
|Published online||17 September 2012|
Miguel A. de Avillez (ed)
EAS Publications Series, 56 (2012) 275–279
Galaxy Interactions and Hi Clouds in Groups
1 Vanderbilt University Physics & Astronomy Department, 1807 Station B, Nashville, TN 37235, USA
2 National Radio Astronomy Observatory, Green Bank, WV 24944, USA
We present GBT neutral hydrogen observations of two nearby galaxy groups. The M 81/M 82 and NGC 2403 groups represent opposite ends of the range in intensity of galaxy interactions, and have remarkably different properties in Hi. We have discovered 5 new Hi clouds in the highly interacting M 81/M 82 group of galaxies. Based on the velocity and angular distributions of these clouds, we conclude that they are relics of ongoing interactions between galaxies in the group. In contrast, the non-interacting NGC 2403 galaxy group shows no signs of Hi clouds or faint, extended Hi. We also detect a compact Hi cloud at v = −205 km s−1, which we believe to be part of HVC Complex A. Our observations suggest that the number density of Hi clouds in galaxy groups is strongly correlated with the level and age of ongoing galaxy interactions in the group.
© EAS, EDP Sciences, 2012