A search for faint resolved galaxies beyond the Milky Way in DES Year 6: A new f
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This product is a result of a search for faint resolved galaxies beyond the Milky Way in the sixth year of the Dark Energy Survey (DES). The product presents a new faint, diffuse dwarf satellite of NGC 55, a galaxy located in the Sculptor group. The discovery of this satellite is significant as it adds to the growing number of faint dwarf galaxies that have been discovered in recent years. The product provides detailed information on the properties of this satellite, including its size, luminosity, and distance from NGC 55. This information is valuable for understanding the formation and evolution of galaxies in the local universe.
We report results from a systematic wide-area search for faint dwarf galaxies at heliocentric distances from 0.3 to 2 Mpc using the full six years of data from the Dark Energy Survey (DES). Unlike previous searches over the DES data, this search specifically targeted a field population of faint galaxies located beyond the Milky Way virial radius. We derive our detection efficiency for faint, resolved dwarf galaxies in the Local Volume with a set of synthetic galaxies and expect our search to be complete to MV ∼ (−7, −10) mag for galaxies at D = (0.3, 2.0) Mpc respectively. We find no new field dwarfs in the DES footprint, but we report the discovery of one high-significance candidate dwarf galaxy at a distance of 2.2 +0.05 −0.12 Mpc, a potential satellite of the Local Volume galaxy NGC 55, separated by 47 arcmin (physical separation as small as 30 kpc). We estimate this dwarf galaxy to have an absolute V-band magnitude of −8.0 +0.5 −0.3 mag and an azimuthally averaged physical half-light radius of 2.2 +0.5 −0.4 kpc, making this one of the lowest surface brightness galaxies ever found with µ = 32.3 mag arcsec−2 . This is the largest, most diffuse galaxy known at this luminosity, suggesting possible tidal interactions with its host.