HI Content and Optical Properties of Field Galaxies from the ALFALFA Survey. I.Selection of a Control Sample

Details HI Content and Optical Properties of Field Galaxies from the ALFALFA Survey. I.Selection of a Control Sample HI Content and Optical Properties of Field Galaxies from the ALFALFA Survey. I.Selection of a Control Sample

2011-03-04

arxiv.org/abs/1103.0900v1

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

41 pages, 13 figures, 3 tables, accepted for publication in The Astrophysical Journal

Scientific paper

We report results from a study of the HI content and stellar properties of nearby galaxies detected by the Arecibo Legacy Fast ALFA blind 21-cm line survey and the Sloan Digital Sky Survey in two declination strips covering a total area of 9 hr X 16 deg. Our analysis seeks to assemble a control sample of galaxies suitable for providing absolute measures of the HI content of gaseous objects. From a database of ~15,000 HI detections, we have assembled three samples of gas-rich galaxies expected to show little or no evidence of interaction with their surroundings that could provide adequate HI standards. The most reliable results are obtained with a sample of 5647 sources found in low density environments, as defined by a nearest neighbor approach. The other two samples contain several hundred relatively isolated galaxies each, as determined from standard isolation algorithms. We find that isolated objects are not particularly gas-rich compared to their low-density-environment counterparts, while they suffer from selection bias and span a smaller dynamic range. All this makes them less suitable for defining a reference for HI content. We have explored the optical morphology of gaseous galaxies in quiet environments finding that, within the volume surveyed, the vast majority of them display unequivocal late-type galaxy features. In contrast, bona fide gas-rich early-type systems account only for a negligible fraction of the 21-cm detections. We argue that HI emission provides the most reliable way to determine the morphological population to which a galaxy belongs. We have also observed that the color distribution of flux-limited samples of optically-selected field HI emitters does not vary significantly with increasing distance, while that of non-detections becomes notably redder. This result suggests that the colors and HI masses of gas-rich galaxies cannot be very closely related.

Affiliated with

Also associated with

No associations

Rating

HI Content and Optical Properties of Field Galaxies from the ALFALFA Survey. I.Selection of a Control Sample does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with HI Content and Optical Properties of Field Galaxies from the ALFALFA Survey. I.Selection of a Control Sample, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and HI Content and Optical Properties of Field Galaxies from the ALFALFA Survey. I.Selection of a Control Sample will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-321105