Quasars to Understand Environments around, and STar formation in, Dwarfs

The Quasars to Understand Environments around, and STar formation in, Dwarfs project leverages incredible multiwavelength data (including FUV spectra along QSO sightlines, optical spectra, and ground- and space-based photometry) to characterize the chemical and physical properties of a diverse sample of dwarf galaxies. We observe the connections between the galaxies’ larger environments, circumgalactic medium, and star formation, enabling detailed and holistic study of the baryon cycle in low mass galaxies (between ~a million and a billion solar masses).

QUEST Dwarfs DR1 is out now on questdwarfs.github.io!

The results of various QUEST Dwarfs papers are summarized briefly here.

• Sample definition and first results (Polzin et al. 2026):
  • CGM constraints from 14 dwarf galaxies (20% of full sample) via 16 sightlines; 9 sightlines withing 0.3 R_vir
  • 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