The HI Mass Function and Velocity Width Function of Void Galaxies in the Arecibo Legacy Fast ALFA Survey
Abstract
We measure the HI mass function (HIMF) and velocity width function (WF) across environments over a range of masses and profile widths using a catalog of ~7,300 HI-selected galaxies from the ALFALFA Survey, located in the region of sky where ALFALFA and SDSS (Data Release 7) North overlap. We divide our galaxy sample into those that reside in large-scale voids (void galaxies) and those that live in denser regions (wall galaxies). We find the void and wall HIMFs are well fit by Schechter functions. We conclude that void galaxies typically have lower HI masses than their non-void counterparts, which is in agreement with the dark matter halo mass function shift in voids; and the void low-mass slope is shallower than that of the wall HIMF suggesting that there is either no excess of low-mass galaxies in voids or there is an abundance of intermediate HI mass galaxies. We fit a modified Schechter function to both the ALFALFA void and wall WFs. Because of large uncertainties on the void and wall WFs, we cannot conclude whether these functions are dependent on environment.
- Publication:
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American Astronomical Society Meeting Abstracts #224
- Pub Date:
- June 2014
- Bibcode:
- 2014AAS...22431808M