We present a study of the metal-enriched cool halo gas traced by MgII absorption around 228 galaxies at z~0.8-1.5 within 28 quasar fields from the MUSE Analysis of Gas around Galaxies (MAGG) survey. 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% complete down to a star formation rate of ~0.1 Msun/yr and up to impact parameters ~250-350 kpc from quasars, we find that the majority (67^{+12}_{-15}% 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. The dependence of MgII absorption on galaxy properties disfavours the scenario in which a widespread intra-group medium dominates the observed absorption. This leaves instead gravitational interactions among group members or hydrodynamic interactions of the galaxy haloes with the intra-group medium as favoured mechanisms to explain the observed enhancement in the MgII absorption strength and cross section in rich environments.

中文翻译：

---

星系周围气体的 MUSE 分析 (MAGG) - II：z ∼ 1 星系周围富含金属的晕气体

我们通过 MUSE 对星系周围气体分析 (MAGG) 调查中的 28 个类星体场中 z~0.8-1.5 处的 228 个星系的 MgII 吸收追踪了富含金属的冷晕气体的研究。我们观察到 MgII 等效宽度与冲击参数关系和 MgII 覆盖率与 z<~0.5 处的调查相比没有显着变化。恒星质量以及距星系中心的距离似乎是影响星系周围 MgII 吸收的主要因素。使用完成度为 90% 的样本，恒星形成率约为 0.1 Msun/yr 以及来自类星体的撞击参数约为 250-350 kpc，我们发现大多数 (67^{+12}_{-15} % 或 14/21) 的 MgII 吸收系统与不止一个星系有关。在这些更丰富的环境中金属的复杂分布增加了先前报告的相关性的大量分散。与孤立的星系相比，多个星系协会在两倍的维里半径内平均表现出强五倍的吸收和三倍的覆盖率。MgII 吸收对星系特性的依赖不利于广泛的群内介质主导观察到的吸收的情况。这使得群成员之间的引力相互作用或星系晕与群内介质的流体动力学相互作用成为解释在丰富环境中观察到的 MgII 吸收强度和横截面增强的有利机制。与孤立的星系相比，多个星系协会在两倍的维里半径内平均表现出强五倍的吸收和三倍的覆盖率。MgII 吸收对星系特性的依赖性不利于广泛的群内介质主导观察到的吸收的情况。这使得群成员之间的引力相互作用或星系晕与群内介质的流体动力学相互作用成为解释在丰富环境中观察到的 MgII 吸收强度和横截面增强的有利机制。与孤立的星系相比，多个星系协会在两倍的维里半径内平均表现出强五倍的吸收和三倍的覆盖率。MgII 吸收对星系特性的依赖性不利于广泛的群内介质主导观察到的吸收的情况。这使得群成员之间的引力相互作用或星系晕与群内介质的流体动力学相互作用成为解释在丰富环境中观察到的 MgII 吸收强度和横截面增强的有利机制。