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J. Gerssen, R. P. van der Marel (STScI), P. Dubath (Geneva Obs.), K. Gebhardt (Univ. of Texas), P. Guhathakurta (Univ. of California), R. Peterson (Astrophysical Advances), C. Pryor (Rutgers Univ.)
We are obtaining stellar absorption line spectra with STIS to measure the radial velocities of individual stars in the crowded central two arcsec of M15. The central power-law cusp observed in the star count distribution provides a unique opportunity to probe the structure and evolution of this globular cluster. The kinematics of the individual stars will reveal whether the observed cusp is consistent with core collapse or whether it is indicative of an intermediate-mass black hole. Initial results show that the few stars that have ground-based radial velocity measurements agree well with the STIS results, and that the STIS measurements will significantly increase the overall number of stars with known radial velocities in the central few arcsec of M15