Affiliation: STScI

Contribution: Oral

Title: The MUSE Ultra-Deep Field: Tracing the baryon cycle through low-mass galaxies since cosmic noon

Abstract: The MUSE Ultra-Deep Field (MUDF) is the deepest field observed with MUSE to-date, with over 140h of observations covering a 2×2 field centered on a pair of z~3 quasars. This is accompanied by numerous datasets from other instruments including ALMA, HAWK-I, UVES, and XMM-Newton, as well as multi-band HST imaging and the deepest ever WFC3 grism survey. Combined, these data provide unprecedented insight into the properties of low-mass galaxies since cosmic noon and the cycle of metals between galaxies and their surroundings. We measure morphologies, stellar masses, and star-formation rates (SFRs) for over 400 galaxies with spectroscopic redshifts. The MUDF features multiple over-densities at different redshifts, revealing galaxy properties across a wide range of environments. Our spectra also allow us to measure metallicities for many of these galaxies, alongside hundreds of metal absorption features arising from the circumgalactic and intergalactic medium along the two quasar sightlines. I will discuss several results enabled by this remarkable dataset. First, we extend measurements of the star-forming main sequence and mass-metallicity relation (MZR) to low stellar masses of 10^7 solar and star-formation rates ~1 dex lower than previous works, finding that the low-mass slope of the MZR depends on SFR but does not flatten at our lowest masses. Using auroral emission lines, we also confirm that strong-line calibrations can reliably be used to measure metallicities out to redshifts of at least z~2.5. Second, we find evidence for gas recycling in the CGM of galaxies with high specific star-formation rates, and that galaxies with metals observed in their CGM remain consistent with the MZR. These results indicate that star formation is an important driver of the cycle of metals through low-mass galaxies since cosmic noon. Finally, I will show how this data could be combined with JWST to push our understanding of the baryon cycle to earlier times.

This contribution can be found here (pdf).