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A DEEP SEARCH FOR FAINT GALAXIES ASSOCIATED WITH VERY LOW REDSHIFT C iv ABSORBERS. III. THE MASS- AND ENVIRONMENT-DEPENDENT CIRCUMGALACTIC MEDIUM

Using Hubble Space Telescope Cosmic Origins Spectrograph observations of 89 QSO sightlines through the Sloan Digital Sky Survey footprint, we study the relationships between C IV absorption systems and the properties of nearby galaxies, as well as the large-scale environment. To maintain sensitivity to very faint galaxies, we restrict our sample to 0.0015 < z < 0.015, which defines a complete galaxy survey to L (SIC) 0.01 L-* or stellar mass M-* (SIC) 10(8) M-circle dot. We report two principal findings. First, for galaxies with impact parameter rho < 1 r(vir), C IV detection strongly depends on the luminosity/stellar mass of the nearby galaxy. C IV is preferentially associated with galaxies with M-* > 10(9.5) M-circle dot; lower-mass galaxies rarely exhibit significant C IV absorption (covering fraction f(C) = 9(-6)(+12)% for 11 galaxies with M-* < 10(9.5) M-circle dot.). Second, C IV detection within the M-* > 10(9.5) M-circle dot. population depends on environment. Using a fixed-aperture environmental density metric for galaxies with rho < 160 kpc at z < 0.055, we find that 57(-13)(+12)% (8/14) of galaxies in low-density regions (regions with fewer than seven L > 0.15 L* galaxies within 1.5 Mpc) have affiliated C IV absorption; however, none (0/7) of the galaxies in denser regions show C IV. Similarly, the C IV detection rate is lower for galaxies residing in groups with dark matter halo masses of M-halo > 10(12.5) M-circle dot. In contrast to C IV, H. I is pervasive in the circumgalactic medium without regard to mass or environment. These results indicate that C IV absorbers with log N(C IV). (SIC) 13.5 cm(-2) trace the halos of M-* > 10(9.5) M-circle dot galaxies but also reflect larger-scale environmental conditions.

Identiferoai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/622446
Date22 November 2016
CreatorsBurchett, Joseph N., Tripp, Todd M., Bordoloi, Rongmon, Werk, Jessica K., Prochaska, J. Xavier, Tumlinson, Jason, Willmer, C. N. A., O’Meara, John, Katz, Neal
ContributorsUniv Arizona, Steward Observ
PublisherIOP PUBLISHING LTD
Source SetsUniversity of Arizona
LanguageEnglish
Detected LanguageEnglish
TypeArticle
Rights© 2016. The American Astronomical Society. All rights reserved.
Relationhttp://stacks.iop.org/0004-637X/832/i=2/a=124?key=crossref.acabe95494a8b712958c917f2f3168e8

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