A Search for Faint Resolved Galaxies Beyond the Milky Way in DES Year 6: A New Faint, Diffuse Dwarf Satellite of NGC 55 Academic Article uri icon

abstract

  • 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 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 mag and an azimuthally averaged physical half-light radius of 2.2 0.4 + 0.5 kpc , making this one of the lowest surface brightness galaxies ever found with = 32.3 mag arcsec 2 . This is the largest, most diffuse galaxy known at this luminosity, suggesting possible tidal interactions with its host.

published proceedings

  • ASTROPHYSICAL JOURNAL

author list (cited authors)

  • McNanna, M., Bechtol, K., Mau, S., Nadler, E. O., Medoff, J., Drlica-Wagner, A., ... Wiseman, P.

complete list of authors

  • McNanna, M||Bechtol, K||Mau, S||Nadler, EO||Medoff, J||Drlica-Wagner, A||Cerny, W||Crnojevic, D||Mutlu-Pakdil, B||Vivas, AK||Pace, AB||Carlin, JL||Collins, MLM||Ferguson, PS||Martinez-Delgado, D||Martinez-Vazquez, CE||Noel, NED||Riley, AH||Sand, DJ||Smercina, A||Tollerud, E||Wechsler, RH||Abbott, TMC||Aguena, M||Alves, O||Bacon, D||Bom, CR||Brooks, D||Burke, DL||Carballo-Bello, JA||Carnero Rosell, A||Carretero, J||da Costa, LN||Davis, TM||De Vicente, J||Diehl, HT||Doel, P||Ferrero, I||Frieman, J||Giannini, G||Gruen, D||Gutierrez, G||Gruendl, RA||Hinton, SR||Hollowood, DL||Honscheid, K||James, DJ||Kuehn, K||Marshall, JL||Mena-Fernandez, J||Miquel, R||Pereira, MES||Pieres, A||Malagon, AA Plazas||Sakowska, JD||Sanchez, E||Sanchez Cid, D||Santiago, B||Sevilla-Noarbe, I||Smith, M||Stringfellow, GS||Suchyta, E||Swanson, MEC||Tarle, G||Weaverdyck, N||Wiseman, P

publication date

  • January 2024