Exploring the Very Extended Low Surface Brightness Stellar Populations
  of the Large Magellanic Cloud with SMASH
  We present the detection of very extended stellar populations around the
Large Magellanic Cloud (LMC) out to R~21 degrees, or ~18.5 kpc at the LMC
distance of 50 kpc, as detected in the Survey of the MAgellanic Stellar History
(SMASH) performed with the Dark Energy Camera on the NOAO Blanco 4m Telescope.
The deep (g~24) SMASH color magnitude diagrams (CMDs) clearly reveal old (~9
Gyr), metal-poor ([Fe/H]=-0.8 dex) main-sequence stars at a distance of 50 kpc.
The surface brightness of these detections is extremely low with our most
distant detection having 34 mag per arcsec squared in g-band. The SMASH radial
density profile breaks from the inner LMC exponential decline at ~13-15 degrees
and a second component at larger radii has a shallower slope with power-law
index of -2.2 that contributes ~0.4% of the LMC's total stellar mass. In
addition, the SMASH densities exhibit large scatter around our best-fit model
of ~70% indicating that the envelope of stellar material in the LMC periphery
is highly disturbed. We also use data from the NOAO Source catalog to map the
LMC main-sequence populations at intermediate radii and detect a steep dropoff
in density on the eastern side of the LMC (at R~8 deg) as well as an extended
structure to the far northeast. These combined results confirm the existence of
a very extended, low-density envelope of stellar material with disturbed shape
around the LMC. The exact origin of this structure remains unclear but the
leading options include a classical accreted halo or tidally stripped outer
disk material.
