HI Cosmology in the Local Universe with ALFALFA
Abstract
The Arecibo Legacy Fast ALFA (ALFALFA) survey is an on-going second generation blind extragalactic HI survey exploiting Arecibo's superior sensitivity, angular resolution and digital technology to conduct a census of the local HI universe over a cosmologically significant volume. As of mid-2007, ~4500 good quality extragalactic HI line sources have been extracted in ~15% of the final survey area. ALFALFA is detecting HI masses as low as 10**6 Msun and as high as 10**10.8 Msun with positional accuracies typically better than 20 arcsec, allowing immediate identification of the most probable optical counterparts. Only 3% of all extragalactic HI sources and fewer than 1% of detections with M(HI) > 10**9.5 Msun cannot be identified with a stellar component. First ALFALFA results already suggest, in agreement with previous studies, that there does not appear to be a cosmologically significant population of optically dark but HI rich galaxies. ALFALFA promises a wealthy dataset for the exploration of many issues in near-field cosmology and galaxy evolution studies, setting the stage for their extension to higher redshifts with the Square Kilometer Array (SKA).
Keywords
Cite
@article{arxiv.0708.2547,
title = {HI Cosmology in the Local Universe with ALFALFA},
author = {Martha P. Haynes},
journal= {arXiv preprint arXiv:0708.2547},
year = {2007}
}
Comments
To appear in ASP Conference Series as proceedings of NRAO 50th Anniversary Symposium, "Frontiers of Astrophysics", June 18-21, 2007, A. Bridle, J. Condon and G. Hunt eds. 10 pages including 4 figures. Higher resolution version available at http://egg.astro.cornell.edu/alfalfa/pubs/haynes_nrao50.pdf