ALFALFA: an Exploration of the z=0 HI Universe

Understand

The Arecibo Legacy Fast ALFA (ALFALFA) Survey is a program aimed at obtaining a census of HI-bearing objects over a cosmologically significant volume of the local Universe.

• It will cover 7074 square degrees of the high latitude sky accessible with the Arecibo 305m telescope, using the 7-beam feed L-band feed array (ALFA).
• Started in February 2005, as of Summer of 2007 survey observations are 44\% complete.
• ALFALFA offers an improvement of about one order of magnitude in sensitivity, 4 times the angular resolution, 3 times the spectral resolution, and 1.6 times the total bandwidth of HIPASS.