Arecibo Ultra Deep Survey data

The Arecibo Ultra Deep Survey (AUDS) has collected about 1110 hr of total integration time in two fields with a combined area of 1.35 deg^2. The data have a sensitivity level of 80μJy. The observations were carried out using the drift and chase mode. The basic strategy is to carry out repeated drift scans over the same field. To optimise uniformity of the sky coverage, the feed array was rotated to ensure the equal spacing between the beams. The data reduction is performed using software livedata. It is programmed to suit the different settings of the Arecibo telescope including handling of different types of FITS files and other Arecibo specific issues such as calibration. The Arecibo Ultra Deep Survey (AUDS) combines the unique sensitivity of the telescope with the wide field of the Arecibo L-band Feed Array (ALFA) to directly detect 21cm HI emission from galaxies at distances beyond the local Universe bounded by the lower frequency limit of ALFA (z=0.16). We successfully detect 118 galaxies in the mass range of log (MHI/h2Msun)=5.6—10.3. We are able to compute the HI mass function at the highest redshifts so far measured. We also find a cosmic HI density of HI (2.7 ± 0.5) x10-4 h-1.