2020/09/30 by Yun-Hsin Huang, Hsiao-Wen Chen, Hsiao‐Wen Chen +7 · 1 citation
Environmental Science · Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Galaxy #Halo #Luminosity #Physics #Plant Water Relations and Carbon Dynamics #QSOS #RADIUS #Redshift #Star formation #Stellar mass #Velocity dispersion #Virial theorem #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stab360
20 pages, 11 figures, accepted for publication in the MNRAS
arxiv created 2021/02/04 · openalex publication_date 2021/02/09 · openalex created_date 2021/02/15 · arxiv updated 2021/02/17 · openalex updated_date 2026/08/06
ABSTRACT This paper presents a survey of Mg ii absorbing gas in the vicinity of 380 random galaxies, using 156 background quasi-stellar objects (QSOs) as absorption-line probes. The sample comprises 211 isolated (73 quiescent and 138 star-forming galaxies) and 43 non-isolated galaxies with sensitive constraints for both Mg ii absorption and H α emission. The projected distances span a range from d = 9 to 497 kpc, redshifts of the galaxies range from z = 0.10 to 0.48, and rest-frame absolute B-band magnitudes range from MB = −16.7 to −22.8. Our analysis shows that the rest-frame equivalent width of Mg ii, Wr(2796), depends on halo radius (Rh), B-band luminosity(LB), and stellar mass (Mstar) of the host galaxies, and declines steeply with increasing d for isolated, star-forming galaxies. At the same time, Wr(2796) exhibits no clear trend for either isolated, quiescent galaxies or non-isolated galaxies. In addition, the covering fraction of Mg ii absorbing gas 〈κ〉 is high with 〈κ〉 ≳ 60 per cent at <40 kpc for isolated galaxies and declines rapidly to 〈κ〉 ≈ 0 at d ≳ 100 kpc. Within the gaseous radius, the incidence of Mg ii gas depends sensitively on both Mstar and the specific star formation rate inferred from H α. Different from what is known for massive quiescent haloes, the observed velocity dispersion of Mg ii absorbing gas around star-forming galaxies is consistent with expectations from virial motion, which constrains individual clump mass to m\rm cl \gtrsim 105 \rm M_\odot and cool gas accretion rate of ∼ 0.7 - 2 M_\odot \rm yr-1. Finally, we find no strong azimuthal dependence of Mg ii absorption for either star-forming or quiescent galaxies. Our results demonstrate that multiple parameters affect the properties of gaseous haloes around galaxies and highlight the need of a homogeneous, absorption-blind sample for establishing a holistic description of chemically enriched gas in the circumgalactic space.