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| Paper: |
HI Cosmology in the Local Universe with ALFALFA |
| Volume: |
395, Frontiers of Astrophysics: A Celebration of NRAO's 50th Anniversary |
| Page: |
125 |
| Authors: |
Haynes, M.P. |
| Abstract: |
The Arecibo Legacy Fast ALFA (ALFALFA) survey is an ongoing 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, ∼4,500 good-quality extragalactic HI line sources have been extracted in ∼15% of the final survey area. ALFALFA is detecting HI masses as low as 106M⊙ and as high as 1010.8M⊙ 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 MHI > 109.5M⊙ 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). |
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