Searching for Dark Galaxies: The AGES VC2 Region

The VC2 strip (part of the AGES blind HI survey) spans 5x1 degrees of the Virgo Cluster, from the outskirts of the cluster to its interior. The strip covers part of subcluster A while avoiding the strong continuum source M87. 40 hours of observations were taken in January-February 2007 using the ALFA instrument on the Arecibo telescope, reaching a noise level as low as 0.5 mJy. For a 200 km/s velocity width, this gives a sensitivity limit of 6*10⁶ M_solar at the Virgo distance (16 Mpc). Currently, 36 definite sources have been found, both by eye and with the automatic extractor Polyfind, with an additional 12 requiring follow-up observations, found only by one method.