QUEST Dwarfs I: First Release

first release CGM measurements, mass-dependence

Polzin et al. (2026)

In this first QUEST Dwarfs paper, we analyze just 20% of our full sample using a combination of broadband imaging, optical spectroscopy, and FUV absorption spectroscopy. We find:

CGM constraints from 14 dwarf galaxies via 16 sightlines; 9 sightlines withing 0.3 R_vir (improvement in number of CGM probes by a ~factor of 3 outside of the Local Group)
Chemically enriched gas is concentrated toward galaxies, apparent multiphase gradient with lower ionization chemical species more concentrated and higher ionization species more extended
Galaxy stellar mass sets the normalization of the CGM gas density profile, with more massive dwarfs also having higher metal column densities; some very weak indication of correlation with metallicity and star formation history, but hard to disentangle from mass dependence and will be explored more in future work
Preliminary analysis of “low-mass” (log M_★/M_☉ < 8) and “high-mass” dwarf bins (log M_★/M_☉ ≥ 8) suggests that the CGM holds ~3% and ~16% respectively of the metals produced by the galaxies