First Results from the Survey of the MAgellanic Stellar History (SMASH)
Abstract
Clear observational signatures of hierarchical galaxy formation have been found around the Milky Way and other nearby massive galaxies. However, the build-up of smaller dwarf galaxies and the extent to which they harbor relics of past interactions such as stellar halos and substructure is not well-known. In an effort to observationally constrain structure formation on small scales, SMASH (Survey of the MAgellanic Stellar History), an approved NOAO community DECam survey, is imaging ~2400 square degrees (at 20% filling factor) to 24th mag in gri (uz~23) allowing us to map the expected stellar debris and extended stellar populations of the Clouds with unprecedented fidelity. SMASH will (a) search for the stellar components of the Magellanic Stream and Leading Arm, (b) detect and map the extended smooth components and substructure of the Magellanic Clouds, and (c) derive spatially resolved, precise star formation histories out to large radii. Our first year of data reveal (1) Large Magellanic Cloud (LMC) stellar populations extending out to a radius of at least 19 deg (~17 kpc) in several directions, (2) clear signatures of two dominant LMC star formation episodes at intermediate radii as revealed by multiple subgiant branches, and (3) evidence for an expansive stellar substructure in the Milky Way halo at a distance of ~30 kpc.
- Publication:
-
American Astronomical Society Meeting Abstracts #225
- Pub Date:
- January 2015
- Bibcode:
- 2015AAS...22511301N