Dr. Rajeshwari Dutta

The formation and evolution of galaxies are shaped by both internal and external processes. In addition to the galaxy disc, secular and environmental processes also affect the ambient gaseous halo or the circumgalactic medium, which is now established to be a crucial component of the galaxy ecosystem. However, to date, most studies of the galaxy-gaseous halo connection have been biased towards the more massive galaxies and lacked a complete census of the local galaxy environment. Thanks to wide-field optical integral field unit spectrographs like the Multi Unit Spectroscopic Explorer (MUSE) on the VLT and near-infrared slit-less grism spectrographs on the HST, we can now conduct a more complete, unbiased and statistical analysis of the galaxy-gaseous halo connection in the context of the small-scale galaxy environment. We have used two large and complete galaxy surveys in quasar fields - the MUSE Analysis of Gas around Galaxies (MAGG) survey and the Quasar Sightline and Galaxy Evolution (QSAGE) survey - to study metal-enriched gaseous haloes out to physical projected separations of 750 kpc and up to z~2. We have investigated the dependence of the low-ionized, cool (T~10^4 K) gas as traced by MgII absorption, and the more highly ionized gas as traced by CIV absorption, on galaxy properties like stellar mass and star formation rate as well as on the galaxy environment. I will present the key results from our studies and demonstrate that environmental processes can have a significant impact on the distribution of metals around galaxies.