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Merging of unequal mass binary black holes in non-axisymmetric galactic nuclei

Published online by Cambridge University Press:  07 March 2016

Peter Berczik ,
Long Wang ,
Keigo Nitadori  and
Rainer Spurzem
Peter Berczik
Affiliation:
National Astronomical Observatories of China, Chinese Academy of Sciences, 20A Datun Rd., Chaoyang District, Beijing 100012, China email: [email protected] Main Astronomical Observatory, National Academy of Sciences of Ukraine, 27 Akademika Zabolotnoho St., 03680, Kyiv, Ukraine Astronomisches Rechen-Institut, Zentrum für Astronomie, University of Heidelberg, Mönchhofstrasse 12-14, 69120, Heidelberg, Germany
Long Wang
Affiliation:
National Astronomical Observatories of China, Chinese Academy of Sciences, 20A Datun Rd., Chaoyang District, Beijing 100012, China email: [email protected] Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China
Keigo Nitadori
Affiliation:
RIKEN Advanced Sciennce Institute, Wako, Japan
Rainer Spurzem
Affiliation:
National Astronomical Observatories of China, Chinese Academy of Sciences, 20A Datun Rd., Chaoyang District, Beijing 100012, China email: [email protected] Astronomisches Rechen-Institut, Zentrum für Astronomie, University of Heidelberg, Mönchhofstrasse 12-14, 69120, Heidelberg, Germany Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China
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Abstract

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In this work we study the stellar-dynamical hardening of unequal mass massive black hole (MBH) binaries in the central regions of galactic nuclei. We present a comprehensive set of direct N-body simulations of the problem, varying both the total mass and the mass ratio of the MBH binary. Our initial model starts as an axisymmetric, rotating galactic nucleus, to describe the situation right after the galaxies have merged, but the black holes are still unbound to each other. We confirm that results presented in earlier works (Berczik et al. 2006; Khan et al. 2013; Wang et al. 2014) about the solution of the “last parsec problem” (sufficiently fast black hole coalescence for black hole growth in cosmological context) are robust for both for the case of unequal black hole masses and large particle numbers. The MBH binary hardening rate depends on the reduced mass ratio through a single parameter function, which quantitatively quite well agrees with standard 3 body scattering theory (see e.g., Hills 1983). Based on our results we conclude that MBH binaries at high redshifts are expected to merge with a factor of ~ 2 more efficiently, which is important to determine the possible overall gravitational wave signals. However, we have not yet fully covered all the possible parameter space, in particular with respect to the preceding of the galaxy mergers, which may lead to a wider variety of initial models, such as initially more oblate and / or even significantly triaxial galactic nuclei. Our N-body simulations were carried out on a new special supercomputers using the hardware acceleration with graphic processing units (GPUs).

Keywords

black holesbinary black holesgalactic nucleistellar dynamics
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 10 , Issue S312: Star Clusters and Black Holes in Galaxies across Cosmic Time , August 2014 , pp. 82 - 85
Copyright
Copyright © International Astronomical Union 2016 

References

Aarseth, S. J., Henon, M., & Wielen, R. 1974, Astron. and Astroph., 37, 183Google Scholar
Begelman, M. C., Blandford, R. D., & Rees, M. J. 1980, Nature, 287, 307Google Scholar
Berczik, P., Merritt, D., & Spurzem, R. 2005, ApJ, 633, 680Google Scholar
Berczik, P., Merritt, D., Spurzem, R., & Bischof, H.-P. 2006, ApJL, 642, L21Google Scholar
Berczik, P., Spurzem, R., Wang, L., Zhong, S., & Huang, S. 2013, in Third International Conference “High Performance Computing”, HPC-UA 2013, p. 52–59, 52–59Google Scholar
Berczik, P., Nitadori, K., Zhong, S., et al. 2011, in International conference on High Performance Computing Kyiv Ukraine, October 8-10, 2011., p. 8-18, 8–18Google Scholar
Berentzen, I., Preto, M., Berczik, P., Merritt, D., & Spurzem, R. 2008, AN, 329, 904Google Scholar
Berentzen, I., Preto, M., Berczik, P., Merritt, D., & Spurzem, R. 2009, ApJ, 695, 455Google Scholar
Einsel, C. & Spurzem, R. 1999, MNRAS, 302, 81Google Scholar
Fukushige, T., Ito, T., Makino, J., et al. 1991, Publ. Aston. Soc. Jpn., 43, 841Google Scholar
Gültekin, K., Richstone, D. O., Gebhardt, K., et al. 2009, ApJ, 698, 198Google Scholar
Harfst, S., Gualandris, A., Merritt, D., et al. 2007, N. Astr., 12, 357CrossRefGoogle Scholar
Hemsendorf, M., Sigurdsson, S., & Spurzem, R. 2002, ApJ, 581, 1256Google Scholar
Hills, J. G. 1983, Astron. J., 88, 1269CrossRefGoogle Scholar
Khan, F. M., Berentzen, I., Berczik, P., et al. 2012, ApJ, 756, 30CrossRefGoogle Scholar
Khan, F. M., Holley-Bockelmann, K., Berczik, P., & Just, A. 2013, ApJ, 773, 100CrossRefGoogle Scholar
Khan, F. M., Just, A., & Merritt, D. 2011, ApJ, 732, 89Google Scholar
Komossa, S. 2006, Mem. Soc. Astron. Italiana, 77, 733Google Scholar
Makino, J. 1997, ApJ, 478, 58Google Scholar
Makino, J., Fukushige, T., Okumura, S. K., & Ebisuzaki, T. 1993, Publ. Aston. Soc. Jpn., 45, 303Google Scholar
Merritt, D. 2006, Reports on Progress in Physics, 69, 2513Google Scholar
Merritt, D. & Poon, M. Y. 2004, ApJ, 606, 788Google Scholar
Preto, M., Berentzen, I., Berczik, P., Merritt, D., & Spurzem, R. 2009, Journal of Physics Conference Series, 154, 012049Google Scholar
Preto, M., Berentzen, I., Berczik, P., & Spurzem, R. 2011, ApJL, 732, L26CrossRefGoogle Scholar
Wang, L., Berczik, P., Spurzem, R., & Kouwenhoven, M. B. N. 2014, ApJ, 780, 164Google Scholar
Yu, Q. 2002, MNRAS, 331, 935Google Scholar