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11.14. Massive black hole binaries in galactic nuclei

Published online by Cambridge University Press:  25 May 2016

Junichiro Makino
Junichiro Makino*
Affiliation:
Department of Systems Science, College of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153, Japan

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Many large ellipticals were believed to have large, flat core, of which the radius is typically a few percents of the effective radius (e.g., Lauer, 1985). However, HST observations (e.g., Lauer et al., 1995) have revealed that they are not flat cores at all. The “cores” observed by HST are actually very shallow central density cusps (ρ ~ r−0.5~–1). Such a shallow cusp poses a serious problem to almost any scenario of the formation of ellipticals. If these ellipticals do not have central black holes (MBHs), we are faced with very strange structure with the velocity dispersion decreasing inward. Neither dissipationless/dissipational collapse nor merging have been able to make such a density distribution.

Type
Part III. Black Holes and Central Activity
Information
Symposium - International Astronomical Union , Volume 184: The Central Regions of the Galaxy and Galaxies , 1998 , pp. 483 - 484
Copyright
Copyright © Kluwer 1998 

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