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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 Sersic 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. 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 $sim 33%$ of our LSBG sample, and $sim 30%$ of these are located within 1 deg of low-redshift galaxy groups and clusters (compared to $sim 8%$ 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 ultra-diffuse galaxies, defined as LSBGs with projected physical effective radii $R_{eff} > 1.5 ,kpc$ and central surface brighthness $mu_0(g) > 24.0, mag ,arcsec^{-2}$. The wide-area sample of LSBGs in DES can be used to test the role of environment on models of LSBG formation and evolution.
We perform a search for stellar streams around the Milky Way using the first three years of multi-band optical imaging data from the Dark Energy Survey (DES). We use DES data covering $sim 5000$ sq. deg. to a depth of $g > 23.5$ with a relative photo
Recent advancements in the imaging of low-surface-brightness objects revealed numerous ultra-diffuse galaxies in the local Universe. These peculiar objects are unusually extended and faint: their effective radii are comparable to the Milky Way, but t
The observed rotation curves of low surface brightness (LSB) galaxies play an essential role in studying dark matter, and indicate that there exists a central constant density dark matter core. However, the cosmological N-body simulations of cold dar
Dark matter (DM) is one of the biggest mystery in the Universe. In this review, after a brief discussion of the DM evidences and the main proposed candidates and scenarios for the DM phenomenon, we focus on recent results on rotating disc galaxies gi
The existence of galaxies with a surface brightness $mu$ lower than the night sky has been known since three decades. Yet, their formation mechanism and emergence within a $rmLambda CDM$ universe has remained largely undetermined. For the first time,