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 $7.2<\log (M_{HI}/M_{\odot })<10.8$, and profile widths $1.3\log (km/s)<\log (W)<2.9\log (km/s)$, 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 HIMF to be well fit by a Schechter function with normalization ${\Phi }^{\ast }=(1.37\pm 0.1)\times 10^{-2}{h}^{3}Mp{c}^{-3}$, characteristic mass $\log (M^{\ast }/M_{\odot })+2\log h_{70}=9.86\pm 0.02$, and low-mass-end slope $\alpha =-1.29\pm 0.02$. Similarly, for wall galaxies, we find best-fitting parameters ${\Phi }^{\ast }=(1.82\pm 0.03)\times 10^{-2}{h}^{3}Mp{c}^{-3}$, $\log (M^{\ast }/M_{\odot })+2\log h_{70}=10.00\pm 0.01$, and $\alpha =-1.35\pm 0.01$. We conclude that void galaxies typically have slightly lower HI masses than their non-void counterparts, which is in agreement with the dark matter halo mass function shift in voids assuming a simple relationship between DM mass and HI mass. We also find that the low-mass slope of the void HIMF is similar to 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 the ALFALFA void WF and determine its best-fitting parameters to be ${\Phi }^{\ast }=0.21\pm 0.1h^{3}Mp{c}^{-3}$, $\log (W^{\ast })=2.13\pm 0.3$, $\alpha =0.52\pm 0.5$ and high-width slope $\beta =1.3\pm 0.4$. For wall galaxies, the WF parameters are: ${\Phi }^{\ast }=0.022\pm 0.009h^{3}Mp{c}^{-3}$, $\log (W^{\ast })=2.62\pm 0.5$, $\alpha =-0.64\pm 0.2$ and $\beta =3.58\pm 1.5$. Because of large uncertainties on the void and wall width functions, we cannot conclude whether the WF is dependent on the environment.

Accepted for publication at MNRAS, 14 pages, 12 figures

References in corpus (13)

• K-corrections and filter transformations in the ultraviolet, optical, and near infrared
• ZOBOV: a parameter-free void-finding algorithm
• The Aspen--Amsterdam Void Finder Comparison Project
• The velocity function in the local environment from LCDM and LWDM constrained simulations
• The Arecibo Legacy Fast ALFA Survey: III. HI Source Catalog of the Northern Virgo Cluster Region
• The Properties of Galaxies in Voids
• Void Statistics in Large Galaxy Redshift Surveys: Does Halo Occupation of Field Galaxies Depend on Environment?
• The Arecibo Legacy Fast ALFA Survey: VI. Second HI Source Catalog of the Virgo Cluster Region
• Where do "red and dead" early-type void galaxies come from?
• Catalog of Isolated Galaxies Selected from the 2MASS Survey
• Large scale structure in the HI Parkes All-Sky Survey: Filling the Voids with HI galaxies?
• The Arecibo Legacy Fast ALFA Survey: V. HI Source Catalog of the Anti-Virgo Region at dec=27 degrees
• The Arecibo Legacy Fast ALFA Survey: VIII. HI Source Catalog of the Anti-Virgo Region at dec = +25 deg

Cited by in corpus (8)

• xGASS: Gas-rich central galaxies in small groups and their connections to cosmic web gas feeding
• The RESOLVE Survey Atomic Gas Census and Environmental Influences on Galaxy Gas Reservoirs
• The Void Galaxy Survey: Photometry, structure and identity of void galaxies
• Spectroscopic Confusion: Its Impact on Current and Future Extragalactic HI Surveys
• UGC 3672: An unusual merging triplet of gas-rich galaxies in the Lynx-Cancer void
• A deep Parkes HI survey of the Sculptor group and filament: HI mass function and environment
• The HI mass function in the Parkes HI Zone of Avoidance survey
• EIG - II. Intriguing characteristics of the most extremely isolated galaxies