PAIRING OF SUPERMASSIVE BLACK HOLES IN UNEQUAL-MASS GALAXY MERGERS

Journal Article · Fri May 01 04:00:00 EDT 2009 · Astrophysical Journal (Online)

DOI:https://doi.org/10.1088/0004-637X/696/1/L89; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21300737

Callegari, Simone; Mayer, Lucio ^[1]; Kazantzidis, Stelios ^[2]; Colpi, Monica ^[3]; Governato, Fabio; Quinn, Thomas ^[4]; Wadsley, James ^[5]

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1. Institute for Theoretical Physics, University of Zuerich, Winterthurerstrasse 190, CH-9057 Zuerich (Switzerland)
2. Center for Cosmology and AstroParticle Physics and Department of Physics and Department of Astronomy, Ohio State University, 191 West Woodruff Avenue, Columbus, OH 43210 (United States)
3. Universita Milano Bicocca, Dipartimento di Fisica G. Occhialini, Piazza della Scienza 3, I-20126 Milano (Italy)
4. Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)
5. Department of Physics and Astronomy, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4M1 (Canada)

We examine the pairing process of supermassive black holes (SMBHs) down to scales of 20-100 pc using a set of N-body/SPH simulations of binary mergers of disk galaxies with mass ratios of 1:4 and 1:10. Our numerical experiments are designed to represent merger events occurring at various cosmic epochs. The initial conditions of the encounters are consistent with the {lambda}CDM paradigm of structure formation, and the simulations include the effects of radiative cooling, star formation (SF), and supernovae feedback. We find that the pairing of SMBHs depends sensitively on the amount of baryonic mass preserved in the center of the companion galaxies during the last phases of the merger. In particular, due to the combination of gasdynamics and SF, we find that a pair of SMBHs can form efficiently in 1:10 minor mergers, provided that galaxies are relatively gas-rich (gas fractions of 30% of the disk mass) and that the mergers occur at relatively high redshift (z {approx} 3), when dynamical friction timescales are shorter. Since 1:10 mergers are most common events during the assembly of galaxies, and mergers are more frequent at high redshift when galaxies are also more gas-rich, our results have positive implications for future gravitational wave experiments such as the Laser Interferometer Space Antenna.

• OSTI ID: 21300737
• Journal Information: Astrophysical Journal (Online), Journal Name: Astrophysical Journal (Online) Journal Issue: 1 Vol. 696; ISSN 1538-4357
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
99 GENERAL AND MISCELLANEOUS
ANTENNAS
BLACK HOLES
COSMOLOGY
GALAXIES
GRAVITATIONAL WAVES
HYDRODYNAMICS
INTERFEROMETERS
MASS
RADIATIVE COOLING
RED SHIFT
SUPERNOVAE