THE SELF-SIMILARITY OF THE CIRCUMGALACTIC MEDIUM WITH GALAXY VIRIAL MASS: IMPLICATIONS FOR COLD-MODE ACCRETION

Journal Article · Fri Feb 01 04:00:00 EST 2013 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/763/2/L42· OSTI ID:22078294

Churchill, Christopher W; Nielsen, Nikole M; Trujillo-Gomez, Sebastian ^[1]; Kacprzak, Glenn G ^[2]

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1. Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States)
2. Center for Astrophysics and Supercomputing, Swinburne University of Technology, Victoria 3122 (Australia)

We apply halo abundance matching to obtain galaxy virial masses, M{sub h}, and radii, R{sub vir}, for 183 'isolated' galaxies from the 'Mg II Absorber-Galaxy Catalog'. All galaxies have spectroscopic redshifts (0.07 {<=} z {<=} 1.12) and their circumgalactic medium (CGM) is probed in Mg II absorption within projected galactocentric distances D {<=} 200 kpc. We examine the behavior of equivalent width, W{sub r} (2796), and covering fraction, f{sub c} , as a function of D, D/R{sub vir}, and M{sub h}. Bifurcating the sample at the median mass log M{sub h}/M{sub Sun} = 12, we find (1) systematic segregation of M{sub h} on the W{sub r} (2796)-D plane (4.0{sigma}); high-mass halos are found at higher D with larger W{sub r} (2796) compared to low-mass halos. On the W{sub r} (2796)-D/R{sub vir} plane, mass segregation vanishes and we find W{sub r} (2796){proportional_to}(D/R{sub vir}){sup -2} (8.9{sigma}). (2) High-mass halos have larger f{sub c} at a given D, whereas f{sub c} is independent of M{sub h} at all D/R{sub vir}. (3) f{sub c} is constant with M{sub h} over the range 10.7 {<=} log M{sub h}/M{sub Sun} {<=} 13.9 within a given D or D/R{sub vir}. The combined results suggest the Mg II absorbing CGM is self-similar with halo mass, even above log M{sub h}/M{sub Sun} {approx_equal} 12, where cold mode accretion is predicted to be quenched. If theory is correct, either outflows or sub-halos must contribute to absorption in high-mass halos such that low- and high-mass halos are observationally indistinguishable using Mg II absorption strength once impact parameter is scaled by halo mass. Alternatively, the data may indicate predictions of a universal shut down of cold-mode accretion in high-mass halos may require revision.

• OSTI ID: 22078294
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 763; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
BIFURCATION
CATALOGS
DISTANCE
GALAXIES
IMPACT PARAMETER
MASS
QUASARS
RED SHIFT
SEGREGATION