| Due to its low density, the circumgalactic medium (CGM) is commonly studied through metal absorption lines using bright background quasars close in projection to the absorber galaxy. However, quasars are rare and typically provide only pencil-beam measurements of the gas properties. Therefore, statistical studies of numerous galaxy-quasar pairs are necessary to study CGM properties. Recent studies (Lopez+2018, Lopez+2020, Tejos+2021) have introduced a technique using extended gravitational arcs as background sources to study the CGM of individual intervening galaxies in a spatially resolved manner. In this work, we apply this technique to a z~1 galaxy (G1). The serendipitous alignment of the background arc with the absorber galaxy allows probing the minor axis at several seeing-independent positions, up to 50 kpc from G1. The kinematics of the Mg II absorption strongly suggest that the absorbing gas is associated with a galactic-scale outflow. We have examined the correlation between Mg II absorption strength and impact parameter, as well as potential chemical enrichment gradients. Furthermore, we have placed stringent constraints on the outflow's geometry using spatial and kinematic data. Our results, which are consistent with the Mg II-impact parameter anticorrelation observed in quasar statistics, suggest no dependence of the absorption strength on inflows or outflows after normalizing the absorptions with galaxy luminosity and impact parameter, but confirm an absorber galaxy luminosity dependence, previously observed by other authors in quasar statistics (e.g. Bordoloi+2011, Chen+2010). Notably, we have observed a particularly high Fe/Mg ratio compared to systems associated with gas accretion along the minor axis. This study marks the fourth Mg II absorbing system analyzed using gravitational arc-tomography. |
