MUSE Analysis of Gas around Galaxies II

We observe no significant evolution in the MgII equivalent width versus impact parameter relation and in the MgII covering fraction compared to surveys at z~<0.5. The stellar mass, along with distance from galaxy centre, appears to be the dominant factor influencing the MgII absorption around galaxies.

With a sample that is 90 per cent complete down to a star formation rate of ~0.1M_{sun}_/yr and up to impact parameters ~250-350kpc from quasars, we find that the majority (67^+12^_-15_ per cent or 14/21) of the MgII absorption systems are associated with more than one galaxy. The complex distribution of metals in these richer environments adds substantial scatter to previously reported correlations. Multiple galaxy associations show on average five times stronger absorption and three times higher covering fraction within twice the virial radius than isolated galaxies.