This paper presents a survey of MgII 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 MgII absorption and H{alpha} emission. The projected distances span a range from d=9 to 497kpc, redshifts of the galaxies range from z=0.10 to 0.48, and rest-frame absolute B-band magnitudes range from M_B_=-16.7 to -22.8. Our analysis shows that the rest-frame equivalent width of MgII, W_r_(2796), depends on halo radius (R_h_), B-band luminosity(L_B_), and stellar mass (M_star_) of the host galaxies, and declines steeply with increasing d for isolated, star-forming galaxies. At the same time, W_r_(2796) exhibits no clear trend for either isolated, quiescent galaxies or non-isolated galaxies. In addition, the covering fraction of MgII absorbing gas is high with >=60 per cent at <40kpc for isolated galaxies and declines rapidly to ~0 at d>=100 kpc. Within the gaseous radius, the incidence of MgII gas depends sensitively on both M_star_ and the specific star formation rate inferred from H{alpha}. Different from what is known for massive quiescent haloes, the observed velocity dispersion of MgII absorbing gas around star-forming galaxies is consistent with expectations from virial motion, which constrains individual clump mass to m_cl_>~10^5^M_{sun} and cool gas accretion rate of ~0.7-2M{sun}_/yr. Finally, we find no strong azimuthal dependence of MgII 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.

Cone search capability for table J/MNRAS/502/4743/table1 (Summary of Faint Galaxy Spectroscopy)

Cone search capability for table J/MNRAS/502/4743/table2 (Summary of the MagE spectroscopic observations of SDSS QSOs)