AN ULTRA-FAINT GALAXY CANDIDATE DISCOVERED IN EARLY DATA FROM THE MAGELLANIC SATELLITES SURVEY

作者：Drlica Wagner A; Bechtol K; Allam S; Tucker D L; Gruendl R A; Johnson M D; Walker A R; James D J; Nidever D L; Olsen K A G; Wechsler R H; Cioni M R L; Conn B C; Kuehn K; Li T S; Mao Y Y; Martin N F; Neilsen E; Noel N E D; Pieres A; Simon J D; Stringfellow G S; van der Marel R P; Yanny B

来源：Astrophysical Journal Letters, 2016, 833(1): L5.

DOI：10.3847/2041-8205/833/1/L5

• galaxies: dwarf
• Local Group
• Magellanic Clouds

We report a new ultra-faint stellar system found in Dark Energy Camera data from the first observing run of the Magellanic Satellites Survey (MagLiteS). MagLiteS. J0644-5953 (Pictor II or Pic II) is a low surface brightness (mu = 28.5(-1)(+1) mag arcsec (-2) within its half-light radius) resolved overdensity of old and metal-poor stars located at a heliocentric distance of 45(-4)(+5) kpc. The physical size(r(1/2) = 46(-11)(+15) pc) and low luminosity(M-V = -3.2(-0.5)(+0.4) mag) of this satellite are consistent with the locus of spectroscopically confirmed ultra-faint galaxies. MagLiteS. J0644-5953 (Pic II) is located 11.3(-0.9)(+3.1) kpc from the Large Magellanic Cloud (LMC), and comparisons with simulation results in the literature suggest that this satellite was likely accreted with the LMC. The close proximity of MagLiteS. J0644-5953 (Pic II) to the LMC also makes it the most likely ultra-faint galaxy candidate to still be gravitationally bound to the LMC.

• 出版日期2016-12-10