SCYON Abstract

Received on August 27 2010

VLT Kinematics for omega Centauri: Further Support for a Central Black Hole

AuthorsEva Noyola, Karl Gebhardt, Markus Kissler-Patig, Nora Lutzgendorf, Behrang Jalali, P. Tim de Zeeuw, and Holger Baumgardt
Affiliation(1) Max-Planck-Institut fuer extraterrestrische Physik
(2) University of Texas
(3) ESO
(4) Leiden University
(5) University of Queensland
Accepted byAstrophysical Journal
Contactnoyola@mpe.mpg.de
URLhttp://arxiv.org/abs/1007.4559
Links

Abstract

The Galactic globular cluster omega Centauri is a prime candidate for hosting an intermediate mass black hole. Recent measurements lead to contradictory conclusions on this issue. We use VLT-FLAMES to obtain new integrated spectra for the central region of omega Centauri. We combine these data with existing measurements of the radial velocity dispersion profile taking into account a new derived center from kinematics and two different centers from the literature. The data support previous measurements performed for a smaller field of view and show a discrepancy with the results from a large proper motion data set. We see a rise in the radial velocity dispersion in the central region to 22.8+-1.2 km/s, which provides a strong sign for a central black hole. Isotropic dynamical models for omega Centauri imply black hole masses ranging from 3.0 to 5.2x104 solar masses depending on the center. The best-fitted mass is 4.7+-1.0x104 solar masses.