Discovery of a Large Stellar Periphery Around the Small Magellanic Cloud

Autor: Nidever, David L., Majewski, Steven R., Munoz, Ricardo R., Beaton, Rachael L., Patterson, Richard J., Kunkel, William E.
Rok vydání: 2011
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1088/2041-8205/733/1/L10
Popis: The Magellanic Clouds are a local laboratory for understanding the evolution and properties of dwarf irregular galaxies. To reveal the extended structure and interaction history of the Magellanic Clouds we have undertaken a large-scale photometric and spectroscopic study of their stellar periphery (the MAgellanic Periphery Survey, MAPS). We present first MAPS results for the Small Magellanic Cloud (SMC): Washington M, T2 + DDO51 photometry reveals metal-poor red giant branch stars in the SMC that extend to large radii (~11 kpc), are distributed nearly azimuthally symmetrically (ellipticity=0.1), and are well-fitted by an exponential profile (out to R~7.5 deg). An ~6 Gyr old, [Fe/H] -1.3 main-sequence turnoff is also evident to at least R=7.3 deg, and as far as 8.4 deg in some directions. We find evidence for a "break" population beyond ~8 radial scalelengths having a very shallow radial density profile that could be either a bound stellar halo or a population of extratidal stars. The distribution of the intermediate stellar component (3Comment: 6 pages, 4 figures, 1 table, accepted for publication in ApJ Letters
Databáze: arXiv