Spatial Gradients of Old Populations in the Sculptor Dwarf Spheroidal Galaxy

Bernard, Edouard; Aparicio, Antonio; Bono, Giuseppe; Cassisi, Santi; Drozdovsky, Igor; Gallart, Carme; Monelli, Matteo; Skillman, Evan; Stetson, Peter B.; Walker, Alistair
Bibliographical reference

NOAO Proposal ID #2008B-0206

Advertised on:
8
2008
Number of authors
10
IAC number of authors
5
Citations
0
Refereed citations
0
Description
We propose to observe six fields in the nearby dwarf spheroidal galaxy (dSph) Sculptor in order to study the stellar populations, and in particular their spatial gradients, through RR Lyrae star populations and deep color-magnitude diagrams (CMD). In addition to provide a complete census of its short-period variable stars, we will use the pulsation properties of the RR Lyrae stars to trace subtle differences in the age and metallicity of the old population. The deep CMDs reaching the oldest main-sequence turnoff (MSTO), on the other hand, will allow a detailed reconstruction of the star formation history of Sculptor from the oldest epoch to the present time as a function of galactocentric distance. The variable star properties and spatially resolved SFHs will be compared with our results concerning Tucana, which is a very isolated dSph at the edge of the Local Group (870 kpc from the Milky Way, versus 100 kpc for Sculptor), yet harboring a very similar CMD to that of Sculptor.