The stellar populations of gas-rich absorbing galaxies detected with VLT/MUSE and ALMA: the essential link to the baryon cycle
Abstract
The physical processes by which the gas is accreted onto galaxies, tranformed into stars and then expelled from galaxies are of paramount importance to galaxy evolution studies. Observationally constraining each of these baryon components in the same systems is however extremely challenging. Absorption lines detected against background quasars offer the most compelling way to study the cold gas in the circumgalactic medium (CGM). We have selected a unique sample of 17 VLT/MUSE quasar fields, comprising 40 z<0.85 absorbers and 120 associated galaxies, some of which are also detected in CO with ALMA. These absorbers have measured N(H I), absorption and emission metallicities and reconstructed 3D kinematics. An additional sample of 200 z<1.2 galaxies have MgII coverage from quasar spectroscopy. Only the powerful combination of high spatial resolution and UV coverage offered by HST will permit to characterise the stellar content of these objects. Therefore, we propose a 40-orbit 3-band UVIS and IR WFC3 imaging campaign to measure their stellar mass, dust content, age of their stellar population, constrain their resolved morphology and large-scale environment. Only the proposed observations will allow us to establish a complete census of the condensed baryons in these systems, to characterise the dynamical structure of the galaxy groups and filaments and to quantify the CGM metal enrichment as a function of stellar mass. Together, these data will provide fresh clues on the baryon cycle, a key component of galaxy formation and evolution.
- Publication:
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HST Proposal
- Pub Date:
- June 2019
- Bibcode:
- 2019hst..prop15939P