Central kinematics of the globular cluster NGC 2808: Upper limit on the mass of an intermediate-mass black hole

Lutzgendorf, N., Kissler-Patig, M., Gebhardt, K., Baumgardt, H., Noyola, E., Jalali, B., De Zeeuw, P. T. and Neumayer, N. (2012) Central kinematics of the globular cluster NGC 2808: Upper limit on the mass of an intermediate-mass black hole. Astronomy and Astrophysics, 542 . doi:10.1051/0004-6361/201219375

Author Lutzgendorf, N.
Kissler-Patig, M.
Gebhardt, K.
Baumgardt, H.
Noyola, E.
Jalali, B.
De Zeeuw, P. T.
Neumayer, N.
Title Central kinematics of the globular cluster NGC 2808: Upper limit on the mass of an intermediate-mass black hole
Journal name Astronomy and Astrophysics   Check publisher's open access policy
ISSN 0004-6361
Publication date 2012-01-01
Year available 2012
Sub-type Article (original research)
DOI 10.1051/0004-6361/201219375
Open Access Status DOI
Volume 542
Total pages 12
Place of publication Les Ulis, France
Publisher E D P Sciences
Language eng
Abstract Context. Globular clusters are an excellent laboratory for stellar population and dynamical research. Recent studies have shown that these stellar systems are not as simple as previously assumed. With multiple stellar populations as well as outer rotation and mass segregation they turn out to exhibit high complexity. This includes intermediate-mass black holes (IMBHs) which are proposed to sit at the centers of some massive globular clusters. Today's high angular resolution ground based spectrographs allow velocity-dispersion measurements at a spatial resolution comparable to the radius of influence for plausible IMBH masses, and to detect changes in the inner velocity-dispersion profile. Together with high quality photometric data from HST, it is possible to constrain black-hole masses by their kinematic signatures. Aims. We determine the central velocity-dispersion profile of the globular cluster NGC 2808 using VLT/FLAMES spectroscopy. In combination with HST/ACS data our goal is to probe whether this massive cluster hosts an IMBH at its center and constrain the cluster mass to light ratio as well as its total mass. Methods. We derive a velocity-dispersion profile from integral field spectroscopy in the center and Fabry Perot data for larger radii. High resolution HST data are used to obtain the surface brightness profile. Together, these data sets are compared to dynamical models with varying parameters such as mass to light ratio profiles and black-hole masses. Results. Using analytical Jeans models in combination with variable M/L V profiles from N-body simulations we find that the best fit model is a no black hole solution. After applying various Monte Carlo simulations to estimate the uncertainties, we derive an upper limit of the back hole mass of M BH < 1 × 10 4 M · (with 95% confidence limits) and a global mass-to-light ratio of M/L V = (2.1 ± 0.2) M ·/L ·.
Keyword Black hole physics
Galaxies: clusters: individual: NGC 2808
Stars: kinematics and dynamics
Q-Index Code C1
Q-Index Status Provisional Code
Grant ID FT0991052
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Mathematics and Physics
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Created: Thu, 24 Oct 2013, 21:11:48 EST by Dr Holger Baumgardt on behalf of School of Mathematics & Physics