A photometrically and kinematically distinct core in the Sextans dwarf spheroidal galaxy
arXiv:astro-ph/0409066 · doi:10.1111/j.1365-2966.2004.08434.x
Abstract
We present the line of sight radial velocity dispersion profile of the Sextans dwarf spheroidal galaxy (dSph), based on a sample of 88 stars extending to about 1 degree (about 1.5 kpc). Like the Draco and Ursa Minor dSphs, Sextans shows some evidence of a fall-off in the velocity dispersion at large projected radii, with significance p=0.96. Surprisingly, the dispersion at the very centre of Sextans is close to zero (with significance p=0.96). We present evidence which suggests that this latter change in the stellar kinematics coincides with changes in the stellar populations within the dSph. We discuss possible scenarios which could lead to a kinematically and photometrically distinct population at the centre of Sextans.
7 pages, 9 figures, accepted for publication in MNRAS