|
Description
In this paper we describe results from the Arecibo Galaxy Environments Survey (AGES). The survey reaches column densities of ~3x10^18^cm^-2^ and masses of ~10^7^M_{sun}_, over individual regions of order 10deg^2^ in size, out to a maximum velocity of 18000km/s. Each surveyed region is centred on a nearby galaxy, group or cluster, in this instance the NGC 7448 group. Galaxy interactions in the NGC 7448 group reveal themselves through the identification of tidal tails and bridges. We find ~2.5 times more atomic gas in the intergalactic medium than in the group galaxies. We identify five new dwarf galaxies, two of which appear to be members of the NGC 7448 group. This is too small, by roughly an order of magnitude, a number of dwarf galaxies to reconcile observation with theoretical predictions of galaxy formation models. If they had observed this region of the sky in previous wide-area blind HI surveys, HIPASS and ALFALFA, they would have detected only 5 and 43 per cent, respectively, of the galaxies we have detected, missing a large fraction of the atomic gas in this volume.
|
