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The Arecibo Legacy Fast ALFA Survey. X. The H I Mass Function and Ω_(HI) from the 40% ALFALFA Survey

Martin, Ann M. and Papastergis, Emmanouil and Giovanelli, Riccardo and Haynes, Martha P. and Springob, Christopher M. and Stierwalt, Sabrina (2010) The Arecibo Legacy Fast ALFA Survey. X. The H I Mass Function and Ω_(HI) from the 40% ALFALFA Survey. Astrophysical Journal, 723 (2). pp. 1359-1374. ISSN 0004-637X.

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The Arecibo Legacy Fast ALFA (ALFALFA) survey has completed source extraction for 40% of its total sky area, resulting in the largest sample of H I-selected galaxies to date. We measure the H I mass function from a sample of 10,119 galaxies with 6.2 < log(M_(HI)/M_☉) < 11.0 and with well-described mass errors that accurately reflect our knowledge of low-mass systems. We characterize the survey sensitivity and its dependence on profile velocity width, the effect of large-scale structure, and the impact of radio frequency interference in order to calculate the H I mass function with both the 1/V_(max) and 2DSWML methods. We also assess a flux-limited sample to test the robustness of the methods applied to the full sample. These measurements are in excellent agreement with one another; the derived Schechter function parameters are φ* (h^(3)_(70) Mpc^(–3) dex^(–1)) = 4.8 ± 0.3 × 10^(–3), log (M*/M_☉) + 2 log h_(70) = 9.96 ± 0.02, and α = –1.33 ± 0.02. We find Ω_(HI) = 4.3 ± 0.3 ×10^(–4) h^(–1)_(70), 16% larger than the 2005 HIPASS result, and our Schechter function fit extrapolated to log (M_(HI)/M_☉) = 11.0 predicts an order of magnitude more galaxies than HIPASS. The larger values of Ω_(HI) and of M* imply an upward adjustment for estimates of the detection rate of future large-scale H I line surveys with, e.g., the Square Kilometer Array. A comparison with simulated galaxies from the Millennium Run and a treatment of photoheating as a method of baryon removal from H I-selected halos indicate that the disagreement between dark matter mass functions and baryonic mass functions may soon be resolved.

Item Type:Article
Related URLs:
URLURL TypeDescription
Giovanelli, Riccardo0000-0001-8884-8492
Haynes, Martha P.0000-0001-5334-5166
Stierwalt, Sabrina0000-0002-2596-8531
Additional Information:© 2010 American Astronomical Society. Received 2010 July 7; accepted 2010 September 8; published 2010 October 21. The authors acknowledge the work of the entire ALFALFA collaboration team in observing, flagging, and extracting the catalog of galaxies used in this work. This work was supported by NSF grants AST-0607007 and AST-9397661 and by grants from the National Defense Science and Engineering Graduate (NDSEG) fellowship and from the Brinson Foundation.
Funding AgencyGrant Number
National Defense Science and Engineering Graduate (NDSEG) FellowshipUNSPECIFIED
Brinson FoundationUNSPECIFIED
Subject Keywords:galaxies: distances and redshifts; galaxies: dwarf; galaxies: luminosity function, mass function; radio lines: galaxies; surveys
Issue or Number:2
Classification Code:PACS: 95.80.+p; 98.62.Ve; 98.58.Ge; 98.62.Ai; 98.62.Gq
Record Number:CaltechAUTHORS:20101207-140450116
Persistent URL:
Official Citation:Ann M. Martin et al 2010 ApJ 723 1359 doi: 10.1088/0004-637X/723/2/1359
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:21218
Deposited By: Jason Perez
Deposited On:08 Dec 2010 21:11
Last Modified:09 Mar 2020 13:19

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