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Observational Evidence for Black Holes in Globular Clusters Karl Gebhardt (UT Austin)
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Results to Date from Dynamical Studies M15 has been painful for many years Gerssen et al. 2003 claim a 2000 Msun BH from radial vels Baumgardt et al. 2003 say no evidence McNamara et al. 2003 say no evidence from proper motions G1 Gebhardt, Rich, & Ho claim 2e4 Msun BH Baumgardt et al. 2003 say no evidence New data being analyzed NGC 6752 Drukkier et al. 2003 claim large M/L increase from pm’s Xie et al. 2003 claim little M/L increase from radial vels Colpi et al. 2003 use pulsars to argue for something massive
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Current BH/sigma correlation using published results
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Comparing M15 radial velocities with proper motions (McNamara et al), using distance as measured from Kraft and Ivans 2003 (11.2 kpc )
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Comparison with Baumgardt et al dispersion profile, including a BH of 1700 Msun.
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Models with adding a BH to Baumgardt profile for the 100% and 0% ns population
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G1 with WFPCG1 with HRC
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NGC6752 Pulsar Strangeness
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Rotation in Galactic clusters
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Central Rotation in Galactic clusters
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Central Surface Brightness Profiles
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BH/sigma correlation using isotropic models
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Conclusions M15 and G1 still have black holes as the best fitting model central light profiles for clusters show a range of slopes rotation in clusters is important to consider many clusters show a statistically significant increase in the central rotation, which has a PA that is not correlated with that of the main body rotation
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