David Merritt


Massive central objects affect both the structure and evolution of galactic nuclei. Adiabatic growth of black holes generates power-law central density profiles with slopes in the range 1.5 <∼ −d log p/d log r <∼ 2.5, in good agreement with the profiles observed in the nuclei of galaxies fainter than MV ≈ −20. However the shallow nuclear profiles of bright galaxies require a different explanation. Binary black holes are an inevitable result of galactic mergers, and the ejection of stars by a massive binary displaces a mass of order the binary’s own mass, creating a core or shallow power-law cusp. This model is at least crudely consistent with core sizes in bright galaxies. Uncertainties remain about the effectiveness of stellar- and gas-dynamical processes at inducing coalescence of binary black holes, and uncoalesced binaries may be common in low-density nuclei. Numerical N-body experiments are not well suited to probing the long-term evolution of black hole binaries due to spurious relaxation. (Refer to PDF file for exact formulas).

Date of creation, presentation, or exhibit



Carnegie Observatories Astrophysics Series 1 (2004) 263 "Coevolution of Black Holes and Galaxies," Proceedings of the Carnegie Observatories Centennial Symposium I. Carnegie Observatories Astrophysics Series. Held at the Sheraton Pasadena Hotel near Carnegie Observatories, Pasadena, CA, USA: 20-25 October 2002||Also archived in: arXiv:astro-ph/0301257 v1 14 Jan 2003 AND Rutgers Astrophysics Preprint Series No. 379 This work was supported by NSF grants AST 00-71099 and AST 02-06031, by NASA grants NAG5-6037 and NAG5-9046, and by grant HST-AR-08759 from STScI. ISBN: 052-18-2449-4Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type

Conference Proceeding

Department, Program, or Center

School of Physics and Astronomy (COS)


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