NOAO >   Observing Info >   Approved Programs >   2010B-0383

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Proposal Information for 2010B-0383


PI: Edward Olszewski, Univ of Arizona, eolszewski@as.arizona.edu
Address: Steward Observatory, 933 N Cherry, Tucson, AZ 85721, USA

CoI: Abi Saha, NOAO
CoI: Knut Olsen, NOAO

Title: A Sensitive Test of Whether the LMC Contains a Tidal Streamer That Extends All the Way to the Carina Dwarf Spheroidal

Abstract: We have developed a technique for measuring the structure of the LMC using MOSAIC2 imaging. Main sequence stars, from I~20.5 to 22.5, provide a sensitive way to measure LMC structure at large angular distances from its center. From our NOAO Survey Program (Saha, PI), we showed that we can trace the LMC out to angular scales of 16 degrees, with effective surface brightnesses as faint as ~34 mag arcsec^- 2. We see a smooth exponential disk out to more than 10 scalelengths. Published data by others using other techniques seems to show a stellar tidal streamer extending more than 20^\circ away ``hiding'' behind the Carina dwarf spheroidal. Since this result would be inconsistent with our smooth, extended disk, and since our measurements of the disk bracket this feature, it is important to verify the existence of this tidal stream using the most populous type of stars available, the main sequence stars. Mapping the extended structure of the LMC is critical for understanding the history of the LMC's interactions with the Milky Way and the existence, or not, of its dark matter halo.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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