期刊
ASTROPHYSICAL JOURNAL LETTERS
卷 828, 期 1, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.3847/2041-8205/828/1/L5
关键词
dark matter; galaxies: dwarf; galaxies: formation; galaxies: halos
资金
- NSF Faculty Early Career Development (CAREER) award [AST-1151462]
- NSF [AST-1412504, PHY-1066293, AST-1211995]
- NASA [NAS5-26555]
- NASA Office of Space Science [NNX09AF08G]
- National Aeronautics and Space Administration through the Planetary Science Division of the NASA Science Mission Directorate [NNX08AR22G]
- National Science Foundation [AST-1238877]
- Division Of Astronomical Sciences
- Direct For Mathematical & Physical Scien [1821987, 1211995] Funding Source: National Science Foundation
- Division Of Astronomical Sciences
- Direct For Mathematical & Physical Scien [1412504] Funding Source: National Science Foundation
We report the discovery of the faintest known dwarf galaxy satellite of a Large Magellanic Cloud (LMC) stellar-mass host beyond the Local Group (LG), based on deep imaging with Subaru/Hyper Suprime-Cam. Magellanic Analog Dwarf Companions And Stellar Halos (MADCASH). J074238+652501-dw lies similar to 35 kpc in projection from NGC 2403, a dwarf spiral galaxy at D approximate to 3.2 Mpc. This new dwarf has Mg = -7.4 +/- 0.4 and a half- light radius of 168 +/- 70. pc, at the calculated distance of 3.39 +/- 0.41 Mpc. The color-magnitude diagram reveals no evidence of young stellar populations, suggesting that MADCASH. J074238+652501-dw is an old, metal-poor dwarf similar to low-luminosity dwarfs in the LG. The lack of either detected HI gas (M-HI/L-V < 0.69M circle dot/L circle dot,based on Green Bank Telescope observations) or GALEX NUV/FUV flux enhancement is consistent with a lack of young stars. This is the first result from the MADCASH survey, which is conducting a census of the stellar substructure and faint satellites in the halos of Local Volume LMC analogs via resolved stellar populations. Models predict a total of similar to 4-10 satellites at least as massive as MADCASH. J074238+652501-dw around a host with the mass of NGC 2403, with 2-3 within our field of view, slightly more than the one such satellite observed in our footprint.
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