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Observations of stellar proper motions near the Galactic Centre


EVIDENCE for a massive black hole at the centre of our Galaxy has been accumulating for the past two decades 1−7. Estimates of the mass of this region have hitherto been based on the spectroscopic determination of radial velocities for stars and gas near the Galactic Centre, combined with the assumption that the stars are moving on largely circular, isotropically distributed orbits. But if this assumption is incorrect, the observations can be explained with a much smaller central mass, perhaps obviating the need for a massive black hole. Here we report the proper motions (motions in the plane of the sky) of 39 stars located between 0.04 and 0.4 pc from the Galactic Centre. We find that the velocity dispersion estimated from the proper motions is in excellent agreement with that obtained from the radial velocities, indicating that the average velocity field is close to isotropic. Taken together, the observations provide strong evidence for a central dark mass of 2.45 ± 0.4 × 106 solar masses (M) located within 0.015 pc of the compact radio source Sgr A*. We place a lower limit of 6.5 × 109 Mpc−3 on the density of the central region, suggesting that it is most probably occupied by a massive black hole.

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  1. Lacy, J. H., Townes, C. H., Geballe, T. R. & Hollenbach, D. J. Astrophys. J. 241, 132–146 (1980).

    Article  ADS  CAS  Google Scholar 

  2. Serabyn, E. & Lacy, J. H. Astrophys. J. 293, 445–458 (1985).

    Article  ADS  CAS  Google Scholar 

  3. Genzel, R., Watson, D. M., Crawford, M. K. & Townes, C. H. Astrophys. J. 297, 766–786 (1985).

    Article  ADS  CAS  Google Scholar 

  4. Sellgren, K., McGinn, M. T., Becklin, E. E. & Hall, D. N. B. Astrophys. J. 359, 112–120 (1990).

    Article  ADS  CAS  Google Scholar 

  5. Krabbe, A. et al. Astrophys. J. 447, L95–L99 (1995).

    Article  ADS  CAS  Google Scholar 

  6. Haller, J. W. et al. Astrophys. J. 456, 194–205 (1986).

    Article  ADS  Google Scholar 

  7. Genzel, R., Thatte, N., Krabbe, A., Kroker, H. & Tacconi-Garman, L. E. Astrophys. J. (in the press).

  8. Hofmann, R. et al. in Progress in Telescope and Instrumentation Technologies (ed. Ulrich, M. H.) 617–621 (Rep. No. 42, ESO, Garching, 1993).

    Google Scholar 

  9. Eckart, A. et al. Nature 355, 526–529 (1992).

    Article  ADS  Google Scholar 

  10. Eckart, A., Genzel, R., Hofmann, R., Sams, B. J. & Tacconi-Garman, L. E. Astrophys. J. 407, L77–L80 (1993).

    Article  ADS  Google Scholar 

  11. Eckart, A., Genzel, R., Hofmann, R., Sams, B. J. & Tacconi-Garman, L. E. Astrophys. J. 445, L23–L26 (1995).

    Article  ADS  CAS  Google Scholar 

  12. Eckart, A. et al. in The Nuclei of Normal Galaxies (eds Genzel, R. & Harris, A. I.) 305–315 (Kluwer, Dordrecht, 1994).

    Book  Google Scholar 

  13. Eckart, A. & Genzel, R. Mon. Not. R. Astron. Soc. (submitted).

  14. Simon, M. et al. Astrophys. J. 360, 95–105 (1990).

    Article  ADS  Google Scholar 

  15. Simons, D. A., Hodapp, K. W. & Becklin, E. E. Astrophys. J. 360, 106–118 (1990).

    Article  ADS  Google Scholar 

  16. McGinn, M. T., Sellgren, K., Becklin, E. E. & Hall, D. N. B. Astrophys. J. 338, 824–840 (1989).

    Article  ADS  Google Scholar 

  17. Rieke, G. H. & Rieke, M. J. Astrophys. J. 330, L33–L37 (1988).

    Article  ADS  Google Scholar 

  18. Lindqvist, M., Habing, H. & Winnberg, A. Astron. Astrophys. 259, 118–127 (1992).

    ADS  Google Scholar 

  19. Greenhill, L. J. et al. Astrophys. J. 440, 619–627 (1995).

    Article  ADS  Google Scholar 

  20. Myoshi, M. et al. Nature 373, 127–129 (1995).

    Article  ADS  Google Scholar 

  21. Morris, M. Astrophys. J. 408, 496–506 (1993).

    Article  ADS  Google Scholar 

  22. Lee, H. M. Mon. Not. R. Aston. Soc. 272, 605–617 (1995).

    Article  ADS  Google Scholar 

  23. Christou, J. C. Exp. Astron. 2, 27–56 (1991).

    Article  ADS  Google Scholar 

  24. Lucy, L. B. Astron. J. 79, 745–754 (1974).

    Article  ADS  Google Scholar 

  25. Reid, M. Ann. Rev. Astron. Astrophys. 31, 345–372 (1993).

    Article  ADS  CAS  Google Scholar 

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Eckart, A., Genzel, R. Observations of stellar proper motions near the Galactic Centre. Nature 383, 415–417 (1996).

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