Limits On Intermediate-Mass Black Holes In Six Galactic Globular Clusters With Integral-Field Spectroscopy

dc.contributor.utaustinauthorGebhardt, K.en_US
dc.creatorLutzgendorf, N.en_US
dc.creatorKissler-Patig, M.en_US
dc.creatorGebhardt, K.en_US
dc.creatorBaumgardt, H.en_US
dc.creatorNoyola, E.en_US
dc.creatorde Zeeuw, P. T.en_US
dc.creatorNeumayer, N.en_US
dc.creatorJalali, B.en_US
dc.creatorFeldmeier, A.en_US
dc.description.abstractContext. The formation of supermassive black holes at high redshift still remains a puzzle to astronomers. No accretion mechanism can explain the fast growth from a stellar mass black hole to several billion solar masses in less than one Gyr. The growth of supermassive black holes becomes reasonable only when starting from a massive seed black hole with mass on the order of 10(2)-10(5) M-circle dot. Intermediate-mass black holes are therefore an important field of research. Especially the possibility of finding them in the centers of globular clusters has recently drawn attention. Searching for kinematic signatures of a dark mass in the centers of globular clusters provides a unique test for the existence of intermediate-mass black holes and will shed light on the process of black-hole formation and cluster evolution. Aims. We are investigating six galactic globular clusters for the presence of an intermediate-mass black hole at their centers. Based on their kinematic and photometric properties, we selected the globular clusters NGC 1851, NGC 1904 (M 79), NGC 5694, NGC 5824, NGC 6093 (M 80), and NGC 6266 (M 62). Methods. We used integral field spectroscopy to obtain the central velocity-dispersion profile of each cluster. In addition we completed these profiles with outer kinematic points from previous measurements for the clusters NGC 1851, NGC 1094, NGC 5824, and NGC 6093. We also computed the cluster photometric center and the surface brightness profile using HST data. After combining these datasets we compared them to analytic Jeans models. We used varying M/L-V profiles for clusters with enough data points in order to reproduce their kinematic profiles in an optimal way. Finally, we varried the mass of the central black hole and tested whether the cluster is better fitted with or without an intermediate-mass black hole. Results. We present the statistical significance, including upper limits, of the black-hole mass for each cluster. NGC 1904 and NGC 6266 provide the highest significance for a black hole. Jeans models in combination with a M/L-V profile obtained from N-body simulations (in the case of NGC 6266) predict a central black hole of M-circle = (3 +/- 1) x10(3) M circle dot for NGC 1904 and M-circle = (2 +/- 1) x10(3) M-circle dot for NGC 6266. Furthermore, we discuss the possible influence of dark remnants and mass segregation at the center of the cluster on the detection of an IMBH.en_US
dc.description.sponsorshipAustralian Research Council Future Fellowship grant FT0991052en_US
dc.identifier.citationLützgendorf, Nora, Markus Kissler-Patig, Karl Gebhardt, Holger Baumgardt, Eva Noyola, P. Tim de Zeeuw, Nadine Neumayer, Behrang Jalali, and Anja Feldmeier. >Limits on intermediate-mass black holes in six Galactic globular clusters with integral-field spectroscopy.> Astronomy & Astrophysics, Vol. 552 (Apr., 2013): A49.en_US
dc.relation.ispartofserialAstronomy & Astrophysicsen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectblack hole physicsen_US
dc.subjectglobular clusters: generalen_US
dc.subjectstars: kinematics anden_US
dc.subjectsurface-brightness profilesen_US
dc.subjectyoung star-clustersen_US
dc.subjectto-light ratioen_US
dc.subjectvelocity dispersionsen_US
dc.subjectrunaway collisionsen_US
dc.subjectcentral kinematicsen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleLimits On Intermediate-Mass Black Holes In Six Galactic Globular Clusters With Integral-Field Spectroscopyen_US

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