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Merging of two galaxies with central black holes

Abstract

OBSERVATIONS of elliptical galaxies show a positive correlation1,2 between total luminosity and core radius, defined as the radius at which surface luminosity becomes half of the central value. This has been taken as evidence against the idea that ellipticals are the result of galaxy mergers, because in simulated mergers3–5 the core radius remained almost constant. In those simulations, the galaxies contained no central black holes, but there is a body of evidence to suggest that such black holes are common in ellipticals6. Here, we present simulations of the merging of identical galaxies with and without central black holes, and find that when black holes are included, the merged galaxy acquires an isothermal core comparable in mass to the sum of the two initial black holes. Furthermore, the ratio of the core radius to the half-mass radius is approximately the same as the ratio of the black hole mass to the total galaxy mass, a result also consistent with observational evidence. These results, which can be understood by means of simple analytical arguments, suggest that most elliptical galaxies contain central black holes with masses comparable to the mass of their cores.

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References

  1. Kormendy, J. Astrophys. J. 295, 73–79 (1985).

    Article  ADS  Google Scholar 

  2. Lauer, T. R. Astrophys. J. 292, 104–121 (1985).

    Article  ADS  CAS  Google Scholar 

  3. Farouki, R. T., Shapiro, S. L. & Duncuan, M. J. Astrophys. J. 265, 597–605 (1983).

    Article  ADS  Google Scholar 

  4. Barnes, J. E. Astrophys. J. 331, 699–717 (1988).

    Article  ADS  Google Scholar 

  5. Okumura, S. K., Ebisuzaki, T. & Makino, J. Publs Astr. Soc. Japan 43 (in the press).

  6. Dressler, A. lAU Symp No. 134, Active Galactic Nuclei (eds Osterbrock, D. E. & Miller, J. S. 217–232 (1989).

    Book  Google Scholar 

  7. Toomre, A. & Toomre, J. Astrophys. J. 178, 623–666 (1972).

    Article  ADS  Google Scholar 

  8. Toomre, A. Evolution of Galaxies and Stellar Populations (eds Tinsely, B. M. & Larson, R. B.) 401–426 (Yale Observatory, New York, 1977).

    Google Scholar 

  9. Schweizer, F. Astrophys. J. 252, 455–460 (1982).

    Article  ADS  Google Scholar 

  10. Bergvall, N., Rönnbeck, J. & Joansson, L. Astr. Astrophys. 222, 49–57 (1989).

    ADS  Google Scholar 

  11. Wright, G. S., James, P. A., Joseph, R. D. & McLean, I. S. Nature 344, 417–419 (1990).

    Article  ADS  Google Scholar 

  12. Kormendy, J. & Djorgovski, S. Ann. Rev. Astr. Astrophys. 27, 235–277 (1989).

    Article  ADS  Google Scholar 

  13. Carlberg, R. L. Astrophys. J. 310, 593–596 (1986).

    Article  ADS  CAS  Google Scholar 

  14. Sadler, E. M. Astr. J. 89, 53–63 (1984).

    Article  ADS  Google Scholar 

  15. Begelman, M. C., Blandford, R. D. & Rees, M. J. Nature 287, 307–309 (1980).

    ADS  Google Scholar 

  16. Rees, M. J. Science 247, 817–823 (1990).

    Article  ADS  CAS  Google Scholar 

  17. Heggie, D. C. & Mathieu, R. D. in The Use of Supercomputers in Stellar Dynamics (eds. McMillan, S. & Hut, P.) 233–235 (Springer, Berlin 1986).

    Book  Google Scholar 

  18. Ito, T., Makino, J., Ebisuzaki, T. & Sugimoto, D. Publs Astr. Soc. Japan 43, 547–555 (1991).

    ADS  Google Scholar 

  19. Aarseth, S. J. Multiple Time Scales (eds Brackhill, J. U. & Cohen, L.) 377–418 (Academic, New York, 1985).

    Google Scholar 

  20. Makino, J. Publs Astr. Soc. Japan (in the press).

  21. Casertano, S. & Hut, P. Astrophys. J. 298, 80–94 (1985).

    Article  ADS  Google Scholar 

  22. Fukushige, T., Ebisuzaki, T. & Makino, J. Publ. Astr. Soc. Japan (submitted).

Download references

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Ebisuzaki, T., Makino, J. & Okumura, S. Merging of two galaxies with central black holes. Nature 354, 212–214 (1991). https://doi.org/10.1038/354212a0

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