The Dark Matter Profile of the Isolated Elliptical Galaxy NGC 1521

NGC 1521 is an isolated elliptical galaxy recently discovered in an XMMAO6pilot survey to search for optimal targets for Xray studies of dark matter onthe galaxy scale. We request a deep (110 ks) followup observation to map itsdark matter profile in detail out to a radius of virgul140 kpc (virgul0.3 r_vir),extending out farther in the halo than achieved to date using Xrays on thegalaxy scale. We will constrain the concentration and virial mass to within +/15% (90% conf.) and compare to the predictions from cosmological simulations,and obtain an independent measurement of the stellar M/L. This observation ofNGC 1521 would be a key addition to the handful of elliptical galaxies whichcurrently possess interesting Xray constraints on their dark matter properties. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]