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
Working Paper
Author
McNanna, M.; Bechtol, K.; Mau, S.; Nadler, E. O.; Medoff, J.; Drlica-Wagner, A.; Cerny, W.; Crnojevic, D.; Mutlu-Pakdil, B.; Vivas, A. K.; Pace, A. B.; Carlin, J. L.; Collins, M. L. M.; Ferguson, P. S.; Martinez-Delgado, D.; Martinez-Vazquez, C. E.; Noel, N. E. D.; Riley, A. H.; Sand, D. J.; Smercina, A.; Tollerud, E.; Wechsler, R. H.; Abbott, T. M. C.; Aguena, M.; Alves, O.; Bacon, D.; Bom, C. R.; Brooks, D.; Burke, D. L.; Carballo-Bello, J. A.; Rosell, A. Carnero; Carretero, J.; da Costa, L. N.; Davis, T. M.; De Vicente, J.; Diehl, H. T.; Doel, P.; Ferrero, I.; Frieman, J.; Giannini, G.; Gruen, D.; Gutierrez, G.; Gruendl, R. A.; Hinton, S. R.; Hollowood, D. L.; Honscheid, K.; James, D. J.; Kuehn, K.; Marshall, J. L.; Mena-Fernandez, J.; Miquel, R.; Pereira, M. E. S.; Pieres, A.; Malagon, A. A. Plazas; Sakowska, J. D.; Sanchez, E.; Cid, D. Sanchez; Santiago, B.; Sevilla-Noarbe, I.; Smith, M.; Stringfellow, G. S.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Weaverdyck, N.; Wiseman, P.
Source
Subject
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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 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 $M_V$ ~ $(-7, -10)$ 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 $2.2\substack{+0.05\\-0.12}$ 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 $-8.0\substack{+0.5\\-0.3}$ mag and an azimuthally averaged physical half-light radius of $2.2\substack{+0.5\\-0.4}$ kpc, making this one of the lowest surface brightness galaxies ever found with $\mu = 32.3$ mag ${\rm arcsec}^{-2}$. This is the largest, most diffuse galaxy known at this luminosity, suggesting possible tidal interactions with its host.
Comment: 20 pages, 7 figures
Comment: 20 pages, 7 figures