Shadows in the Dark: Low-surface-brightness Galaxies Discovered in the Dark Energy Survey
Abstract
We present a catalog of 23,790 extended low-surface-brightness galaxies (LSBGs) identified in $\sim 5000\,{\deg }^{2}$ from the first three years of imaging data from the Dark Energy Survey (DES). Based on a single-component Sérsic model fit, we define extended LSBGs as galaxies with g-band effective radii ${R}_{\mathrm{eff}}(g)\gt 2\buildrel{\prime\prime}\over{.} 5$ and mean surface brightness ${\bar{\mu }}_{\mathrm{eff}}(g)\gt 24.2\,\mathrm{mag}\,{\mathrm{arcsec}}^{-2}$ . We find that the distribution of LSBGs is strongly bimodal in (g - r) versus (g - i) color space. We divide our sample into red (g - i ≥ 0.60) and blue (g - i < 0.60) galaxies and study the properties of the two populations. Redder LSBGs are more clustered than their blue counterparts and are correlated with the distribution of nearby (z < 0.10) bright galaxies. Red LSBGs constitute ∼33% of our LSBG sample, and $\sim 30 \% $ of these are located within 1° of low-redshift galaxy groups and clusters (compared to ∼8% of the blue LSBGs). For nine of the most prominent galaxy groups and clusters, we calculate the physical properties of associated LSBGs assuming a redshift derived from the host system. In these systems, we identify 41 objects that can be classified as ultradiffuse galaxies, defined as LSBGs with projected physical effective radii ${R}_{\mathrm{eff}}\gt 1.5\,\mathrm{kpc}$ and central surface brightness ${\mu }_{0}(g)\gt 24.0\,\mathrm{mag}\,{\mathrm{arcsec}}^{-2}$ . The wide-area sample of LSBGs in DES can be used to test the role of environment on models of LSBG formation and evolution.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- February 2021
- DOI:
- 10.3847/1538-4365/abca89
- arXiv:
- arXiv:2006.04294
- Bibcode:
- 2021ApJS..252...18T
- Keywords:
-
- Sky surveys;
- Low surface brightness galaxies;
- 1464;
- 940;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 31 pages, 19 figures. Version accepted for publication in ApJS. Data products related to this work can be found in: https://des.ncsa.illinois.edu/releases/other/y3-lsbg