Relativistic Suppression of Black Hole Recoils
Abstract
Numerical-relativity simulations indicate that the black hole produced in a binary merger can recoil with a velocity up to v_(max) ≃ 4000 km s^(−1) with respect to the center of mass of the initial binary. This challenges the paradigm that most galaxies form through hierarchical mergers, yet retain supermassive black holes (SBHs) at their centers despite having escape velocities much less than v_(max). Interaction with a circumbinary disk can align the binary black hole spins with their orbital angular momentum, reducing the recoil velocity of the final black hole produced in the subsequent merger. However, the effectiveness of this alignment depends on highly uncertain accretion flows near the binary black holes. In this paper, we show that if the spin S_1 of the more massive binary black hole is even partially aligned with the orbital angular momentum L, relativistic spin precession on sub-parsec scales can align the binary black hole spins with each other. This alignment significantly reduces the recoil velocity even in the absence of gas. For example, if the angle between S_1 and L at large separations is 10° while the second spin S_2 is isotropically distributed, the spin alignment discussed in this paper reduces the median recoil from 864 km s^(−1) to 273 km s^(−1) for maximally spinning black holes with a mass ratio of 9/11. This reduction will greatly increase the fraction of galaxies retaining their SBHs.
Additional Information
© 2010 The American Astronomical Society. Received 2010 March 24; accepted 2010 April 14; published 2010 May 5. We are grateful to Vitor Cardoso for testing our PN evolution code. We also thank Enrico Barausse,Manuela Campanelli, Yanbei Chen, Pablo Laguna, Carlos Lousto, Samaya Nissanke, Evan Ochsner, Sterl Phinney, Etienne Racine, Luciano Rezzolla, and Manuel Tiglio for useful discussions. This work was supported by grants from the Sherman Fairchild Foundation to Caltech, by NSF grant Nos. PHY-0601459 (PI: Thorne) and PHY-090003 (TeraGrid), and by FCT-Portugal through projects PTDC/CTE-AST/098034/2008 and PTDC/FIS/098032/2008. M.K. acknowledges support from the NASA BEFS grant NNX07AH06G (PI: Phinney). E.B.'s and U.S.'s research was supported by NSF grants PHY-0900735 and PHY-0652995, respectively.Attached Files
Published - Kesden2010p10221Astrophys_J.pdf
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Additional details
- Eprint ID
- 18628
- Resolver ID
- CaltechAUTHORS:20100609-140211088
- Sherman Fairchild Foundation
- PHY-0601459
- NSF
- PHY-090003
- NSF
- PTDC/CTE-AST/098034/2008
- Fundação para a Ciência ea Tecnologia (FCT)
- PTDC/FIS/098032/2008
- Fundação para a Ciência ea Tecnologia (FCT)
- NNX07AH06G
- NASA
- PHY-0900735
- NSF
- PHY-0652995
- NSF
- Created
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2010-06-13Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field