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A Search for Faint Resolved Galaxies Beyond the Milky Way in DES Year 6: A New Faint, Diffuse Dwarf Satellite of NGC 55
- Source :
- The Astrophysical Journal, Vol 961, Iss 1, p 126 (2024)
- Publication Year :
- 2024
- Publisher :
- IOP Publishing, 2024.
-
Abstract
- 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 6 yr 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 M _V ∼ (−7, −10) mag for galaxies at D = (0.3, 2.0) Mpc. 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 ${2.2}_{-0.12}^{+0.05}\,\mathrm{Mpc}$ , a potential satellite of the Local Volume galaxy NGC 55, separated by 47′ (physical separation as small as 30 kpc). We estimate this dwarf galaxy to have an absolute V -band magnitude of $-{8.0}_{-0.3}^{+0.5}\,\mathrm{mag}$ and an azimuthally averaged physical half-light radius of ${2.2}_{-0.4}^{+0.5}\,\mathrm{kpc}$ , making this one of the lowest surface brightness galaxies ever found with $\mu =32.3\,\mathrm{mag}\,{\mathrm{arcsec}}^{-2}$ . This is the largest, most diffuse galaxy known at this luminosity, suggesting possible tidal interactions with its host.
- Subjects :
- Local Group
Low surface brightness galaxies
Dwarf galaxies
Astrophysics
QB460-466
Subjects
Details
- Language :
- English
- ISSN :
- 15384357
- Volume :
- 961
- Issue :
- 1
- Database :
- Directory of Open Access Journals
- Journal :
- The Astrophysical Journal
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.6eeaf2d50e01496096fc1246608fe51f
- Document Type :
- article
- Full Text :
- https://doi.org/10.3847/1538-4357/ad07d0