Shadows in the Dark: Low-Surface-Brightness Galaxies Discovered in the Dark Energy Survey

Understand

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 S\'ersic model fit, we define extended LSBGs as galaxies with $g$-band effective radii $R_{eff}(g) > 2.5''$ and mean surface brightness $\bar{\mu}_{eff}(g) > 24.2 \,mag \.arcsec^{-2}$.
• We find that the distribution of LSBGs is strongly bimodal in $(g-r)$ vs.\ $(g-i$) color space.
• We divide our sample into red ($g-i \geq 0.60$) and blue ($g-i<0.60$) galaxies and study the properties of the two populations.