SAGAbg. I. A Near-unity Mass-loading Factor in Low-mass Galaxies via Their Low-redshift Evolution in Stellar Mass, Oxygen Abundance, and Star Formation Rate
Abstract
Measuring the relation between star formation and galactic winds is observationally difficult. In this work we make an indirect measurement of the mass-loading factor (the ratio between the mass outflow rate and star formation rate) in low-mass galaxies using a differential approach to modeling the low-redshift evolution of the star-forming main sequence and mass–metallicity relation. We use Satellites Around Galactic Analogs (SAGA) background galaxies, i.e., spectra observed by the SAGA Survey that are not associated with the main SAGA host galaxies, to construct a sample of 11,925 spectroscopically confirmed low-mass galaxies from 0.01 ≲ z ≤ 0.21 and measure auroral line metallicities for 120 galaxies. The crux of the method is to use the lowest-redshift galaxies as the boundary condition of our model, and to infer a mass-loading factor for the sample by comparing the expected evolution of the low-redshift reference sample in stellar mass, gas-phase metallicity, and star formation rate against the observed properties of the sample at higher redshift. We infer a mass-loading factor of
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 2024
- DOI:
- 10.3847/1538-4357/ad3042
- arXiv:
- arXiv:2401.16469
- Bibcode:
- 2024ApJ...966..129K
- Keywords:
-
- Amorphous irregular galaxies;
- Dwarf irregular galaxies;
- Galaxy winds;
- Galaxy chemical evolution;
- 37;
- 417;
- 626;
- 580;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 37 pages, 19 figures, accepted to ApJ