학술논문
A Search for Faint Resolved Galaxies Beyond the Milky Way in DES Year 6: A New Faint, Diffuse Dwarf Satellite of NGC 55
Document Type
article
Author
M. McNanna; K. Bechtol; S. Mau; E. O. Nadler; J. Medoff; A. Drlica-Wagner; W. Cerny; D. Crnojević; B. Mutlu-Pakdıl; A. K. Vivas; A. B. Pace; J. L. Carlin; M. L. M. Collins; P. S. Ferguson; D. Martínez-Delgado; C. E. Martínez-Vázquez; N. E. D. Noel; A. H. Riley; D. J. Sand; A. Smercina; E. Tollerud; R. H. Wechsler; T. M. C. Abbott; M. Aguena; O. Alves; D. Bacon; C. R. Bom; D. Brooks; D. L. Burke; J. A. Carballo-Bello; A. Carnero Rosell; J. Carretero; L. N. da Costa; T. M. Davis; J. De Vicente; H. T. Diehl; P. Doel; I. Ferrero; J. Frieman; G. Giannini; D. Gruen; G. Gutierrez; R. A. Gruendl; S. R. Hinton; D. L. Hollowood; K. Honscheid; D. J. James; K. Kuehn; J. L. Marshall; J. Mena-Fernández; R. Miquel; M. E. S. Pereira; A. Pieres; A. A. Plazas Malagón; J. D. Sakowska; E. Sanchez; D. Sanchez Cid; B. Santiago; I. Sevilla-Noarbe; M. Smith; G. S. Stringfellow; E. Suchyta; M. E. C. Swanson; G. Tarle; N. Weaverdyck; P. Wiseman; DES & DELVE Collaboration
Source
The Astrophysical Journal, Vol 961, Iss 1, p 126 (2024)
Subject
Language
English
ISSN
1538-4357
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.