VLT Kinematics for omega Centauri: Further Support for a Central Black Hole
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 5.2x10^4 solar masses depending on the center. The best-fitted mass is 4.7+-1.0x10^4 solar masses.
Keywords
Cite
@article{arxiv.1007.4559,
title = {VLT Kinematics for omega Centauri: Further Support for a Central Black Hole},
author = {Eva Noyola and Karl Gebhardt and Markus Kissler-Patig and Nora Lutzgendorf and Behrang Jalali and P. Tim de Zeeuw and Holger Baumgardt},
journal= {arXiv preprint arXiv:1007.4559},
year = {2015}
}
Comments
5 pages, published in The Astrophysical Journal Letters