期刊
ASTROPHYSICAL JOURNAL
卷 795, 期 1, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/795/1/31
关键词
galaxies: halos; intergalactic medium; quasars: absorption lines
资金
- NSF [AST-1109665]
- Alfred P. Sloan foundation
- Theodore Dunham, Jr., Grant of Fund for Astrophysical Research
- National Science Foundation
- U.S. Department of Energy
- National Aeronautics and Space Administration
- Japanese Monbukagakusho
- Max Planck Society
- Higher Education Funding Council for England
- U.S. Department of Energy Office of Science
- University of Arizona
- Brookhaven National Laboratory
- University of Cambridge
- Carnegie Mellon University
- University of Florida
- Harvard University
- Instituto de Astrofisica de Canarias
- Johns Hopkins University
- Lawrence Berkeley National Laboratory
- Max Planck Institute for Astrophysics
- Max Planck Institute for Extraterrestrial Physics
- New Mexico State University
- New York University
- Ohio State University
- Pennsylvania State University
- University of Portsmouth
- Princeton University
- University of Tokyo
- University of Utah
- Vanderbilt University
- University of Virginia
- University of Washington
- Yale University
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [1313302] Funding Source: National Science Foundation
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [1109665] Funding Source: National Science Foundation
We explore the distribution of cool (similar to 10(4) K) gas around galaxies and its dependence on galaxy properties. By cross-correlating about 50,000 Mg II absorbers with millions of sources from the SDSS (optical), WISE (IR), and GALEX (UV) surveys we effectively extract about 2000 galaxy-absorber pairs at z similar to 0.5 and probe relations between absorption strength and galaxy type, impact parameter and azimuthal angle. We find that cool gas traced by Mg II absorbers exists around both star-forming and passive galaxies with a similar incidence rate on scales greater than 100 kpc but each galaxy type exhibits a different behavior on smaller scales: Mg II equivalent width does not correlate with the presence of passive galaxies whereas stronger Mg II absorbers tend to be found in the vicinity of star-forming galaxies. This effect is preferentially seen along the minor axis of these galaxies, suggesting that some of the gas is associated with outflowing material. In contrast, the distribution of cool gas around passive galaxies is consistent with being isotropic on the same scales. We quantify the average excess Mg II equivalent width as a function of galaxy properties and find alpha SFR1.2, sSFR(0.5), and M-*(0.4) for star-forming galaxies. This work demonstrates that the dichotomy between star-forming and passive galaxies is reflected in the circumgalactic medium traced by low-ionized gas. We also measure the covering fraction of Mg II absorption and find it to be about 2-10 times higher for star-forming galaxies than passive ones within 50 kpc. We estimate the amount of neutral gas in the halo of < log M-*/M circle dot > similar to 10.8 galaxies to be a few x 10(9) M circle dot for both types of galaxies. Finally, we find that correlations between absorbers and sources detected in the UV and IR lead to physical trends consistent with those measured in the optical.
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