| Studying the CGM in emission presents a major challenge, because of its exceedingly low gas densities, and thus, it requires the use of very deep data. On the other hand, it provides a panoramic view of the gas around galaxies, instead of the discrete sampling on which absorption line studies rely. I will present the discovery of a rare Mg II 2796, 2803 doublet emission halo around a star-forming galaxy in the MUSE-HUDF mosaic. The galaxy presents discernible P-Cyg features in its central region, and a remarkable extended Mg II emission halo, on scales of approximately ~30 kpc from the central galaxy. We use an outflow radiative transfer modeling scheme to interpret the observations and shed light on the properties of galactic winds. The model reproduces several key features of the observed Mg II halo and allows us to put constraints on the kinematics and geometry of the outflowing gas. This analysis underscores the complexity of galactic outflows and is encouraging to expand our modeling to a larger sample of galaxies, covering the parameter space in terms of stellar masses, star formation rates, and redshift, and explore the existence of trends between the properties of galaxies and their CGM, from an observational point of view. |
