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Title: An ultra-faint galaxy candidate discovered in early data from the Magellanic Satellites Survey

Here, 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 ($$\mu ={28.5}_{-1}^{+1}\,\mathrm{mag}\,\,\mathrm{arcsec}{}^{-2}$$ within its half-light radius) resolved overdensity of old and metal-poor stars located at a heliocentric distance of $${45}_{-4}^{+5}\,\mathrm{kpc}$$. The physical size ($${r}_{1/2}={46}_{-11}^{+15}\,\mathrm{pc}\,$$) and low luminosity ($${M}_{V}=-{3.2}_{-0.5}^{+0.4}\,\mathrm{mag}\,$$) of this satellite are consistent with the locus of spectroscopically confirmed ultra-faint galaxies. MagLiteS J0644–5953 (Pic II) is located $${11.3}_{-0.9}^{+3.1}\,\mathrm{kpc}\,$$ 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.
Authors:
ORCiD logo [1] ;  [2] ;  [1] ;  [1] ; ORCiD logo [3] ;  [4] ; ORCiD logo [5] ;  [5] ; ORCiD logo [6] ; ORCiD logo [6] ; ORCiD logo [7] ;  [8] ; ORCiD logo [9] ;  [10] ;  [1] ;  [11] ; ORCiD logo [12] ;  [1] ;  [13] ;  [14] more »;  [15] ; ORCiD logo [16] ; ORCiD logo [17] ; ORCiD logo [1] « less
  1. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
  2. Wisconsin IceCube Particle Astrophysics Center (WIPAC), Madison, WI (United States); Univ. of Wisconsin-Madison, Madison, WI (United States)
  3. Univ. of Illinois, Urbana, IL (United States); National Center for Supercomputing Applications, Urbana, IL (United States)
  4. National Center for Supercomputing Applications, Urbana, IL (United States)
  5. National Optical Astronomy Observatory, La Serena (Chile)
  6. National Optical Astronomy Observatory, Tucson, AZ (United States)
  7. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  8. Univ. Potsdam, Potsdam (Germany); Leibnitz-Institut fur Astrophysik Potsdam, Potsdam (Germany); Univ. of Hertfordshire, Hatfield (United Kingdom)
  9. Mount Stromlo Observatory, Weston Creek, ACT (Australia)
  10. Australian Astronomical Observatory, North Ryde, NSW (Australia)
  11. Univ. of Pittsburgh, Pittsburgh, PA (United States)
  12. Univ. de Strasbourg, Strasbourg (France); Max-Planck-Institut fur Astronomie, Heidelberg (Germany)
  13. Univ. of Surrey, Guildford (United Kingdom)
  14. Instituto de Fisica, Porto Alegre (Brazil); Lab. Interinstitucional de e-Astronomia - LIne A, Rio de Janeiro (Brazil)
  15. Carnegie Observatories, Pasadena, CA (United States)
  16. Univ. of Colorado, Boulder, CO (United States)
  17. Space Telescope Science Institute, Baltimore, MD (United States)
Publication Date:
Report Number(s):
FERMILAB-PUB-16-353-AE; arXiv:1609.02148
Journal ID: ISSN 2041-8213; 1485663
Grant/Contract Number:
AC02-07CH11359; AC02-76SF00515
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal. Letters
Additional Journal Information:
Journal Volume: 833; Journal Issue: 1; Journal ID: ISSN 2041-8213
Publisher:
Institute of Physics (IOP)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: dwarf; Local Group; Magellanic Clouds
OSTI Identifier:
1335137
Alternate Identifier(s):
OSTI ID: 1368583