2014ApJ...793L...7S -
Astrophys. J., 793, L7 (2014/September-3)
Discovery of a new faint dwarf galaxy associated with NGC 253.
SAND D.J., CRNOJEVIC D., STRADER J., TOLOBA E., SIMON J.D., CALDWELL N., GUHATHAKURTA P., McLEOD B. and SETH A.C.
Abstract (from CDS):
We report the discovery of a new faint dwarf galaxy, which we dub Scl-MM-Dw1, at a projected distance of ∼65 kpc from the spiral galaxy NGC 253. The discovery results from the Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS), a program with the Magellan/Megacam imager to study faint substructure in resolved stellar light around massive galaxies outside of the Local Group. We measure a tip of the red giant branch distance to Scl-MM-Dw1 of D = 3.9±0.5 Mpc, consistent with that of NGC 253, making their association likely. The new dwarf's stellar population is complex, with an old, metal-poor red giant branch ( ≳ 10 Gyr, [Fe/H] ∼ -2), and an asymptotic giant branch with an age of ∼500 Myr. Scl-MM-Dw1 has a half-light radius of rh= 340±50 pc and an absolute magnitude of MV= -10.3±0.6 mag, comparable to the Milky Way's satellites at the same luminosity. Once complete, our imaging survey of NGC 253 and other nearby massive galaxies will provide a census of faint substructure in halos beyond the Local Group, both to put our own environment into context and to confront models of hierarchical structure formation.
Abstract Copyright:
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Journal keyword(s):
dark matter - galaxies: dwarf
Nomenclature:
[SCS2014] SCl-MM-DwN (No. Dw1).
Simbad objects:
12
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