Program: GN-2016A-Q-67

We propose to undertake a detailed chemical analysis of the Sagittarius (Sgr) tidal stream by obtaining high-resolution spectra of ~40 members of the highest surface brightness portions of both the trailing and leading arms of the Sgr stream. Sgr is a recently infallen, currently disrupting dwarf spheroidal galaxy, with roughly 70% of the luminosity of the Sgr system residing in the tidal streams. Thus the Sgr streams are critical for understanding chemical evolution in dwarf galaxy environments and the process of satellite accretion. To date, the streams have not been well studied chemically. Deriving abundances in the highest surface brightness portions of the stream will allow us to combine information from tidal disruption models of Sgr and detailed star formation histories in the core to tie together the tidal and chemical evolution of Sgr. To select Sgr tidal stream candidates, we will use a 2MASS+WISE color-color selection, combined with LAMOST/LEGUE radial velocities. We thus expect to very efficiently select Sgr stream members for chemical abundance analysis, with little contamination from field stars. This study will provide a link between the (known) chemical properties in the intact Sgr core and the significant portion of the Sgr system's luminosity that is estimated to currently reside in the streams.