Program: GN-2007A-Q-37

Title:Globular Clusters as Probes of Galaxy Formation
PI:Terry Bridges
Co-I(s): Mark Norris, Ray Sharples, Steve Zepf, Mike Beasley, Karl Gebhardt, Dave Hanes, Juan Forte, Favio Faifer, Duncan Forbes

Abstract

Globular clusters (GCs) provide crucial constraints on models for galaxy formation and structure in the Universe as well as the amount and distribution of galactic dark matter. We request time to expand our sample of GC velocities for the Virgo elliptical galaxy NGC 4649 (M60), from our current 38 to ~180. Using a novel approach pioneered by this group, we will also extract kinematics for the stellar population of NGC 4649 beyond 4 effective radii from the same MOS exposures used in the GC investigation. With our existing sample of 38 GC velocities, we were able to measure the orbital properties only by combining with the potential derived from x-rays. An increased sample will allow us to examine both the orbital structure of metal poor/rich GCs (which we could not do before), and determine the gravitational potential directly from the GCs, providing an important cross check on using the x-ray derived potential.

Publications using this program's data