Space Science Reviews

, Volume 100, Issue 1–4, pp 129–138 | Cite as

Mass distribution in our Galaxy

  • Ortwin Gerhard


This article summarizes recent work on the luminosity and mass distribution of the galactic bulge and disk, and on the mass of the Milky Way's dark halo. A new luminosity model consistent with the COBE NIR data and the apparent magnitude distributions of bulge clump giant stars has bulge/bar length of ≃3.5 kpc, axis ratios of 1:(0.3–0.4):0.3, and short disk scale-length (≃2.1 kpc). Gas-dynamical flows in the potential of this model with constant M/L fit the terminal velocities in 10° le|l|le50° very well. The luminous mass distribution with this M/L is consistent with the surface density of known matter near the Sun, but still underpredicts the microlensing optical depth towards the bulge. Together, these facts argue strongly for a massive, near-maximal disk in our ∼L*, Sbc spiral galaxy. While the outer rotation curve and global mass distribution are not as readily measured as in similar spiral galaxies, the dark halo mass estimated from satellite velocities is consistent with a flat rotation curve continuing on from the luminous mass distribution.


Mass Distribution Rotation Curve Spiral Galaxy Apparent Magnitude Dark Halo 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Alcock, C. et al.: 1997, Astrophys. J. 479, 119.Google Scholar
  2. Alcock, C. et al.: 2000a, Astrophys. J. 541, 734.Google Scholar
  3. Alcock, C. et al.: 2000b, Astrophys. J. 542, 281.Google Scholar
  4. Binney, J.J. and Evans, N.W., 2001, Monthly Notices Roy. Astron. Soc. 327, L27.Google Scholar
  5. Binney, J.J., Bissantz N. and Gerhard, O.E.: 2000, Astrophys. J. 537, L99.Google Scholar
  6. Binney, J.J., Gerhard, O.E. and Spergel, D.N.: 1997, Monthly Notices Roy. Astron. Soc. 288, 365. (BGS)Google Scholar
  7. Bissantz, N. and Gerhard, O.E.: 2002, Monthly Notices Roy. Astron. Soc., in press.Google Scholar
  8. Bissantz, N., Englmaier, P., Binney, J.J. and Gerhard, O.E.: 1997, Monthly Notices Roy. Astron. Soc. 289, 651.Google Scholar
  9. Bissantz, N., Englmaier, P. and Gerhard, O.E.: 2002, Monthly Notices Roy. Astron. Soc., submitted.Google Scholar
  10. Courteau, S. and Rix, H.-W.: 1999, Astrophys. J. 513, 561.Google Scholar
  11. Dame, T.M., Hartmann, D. and Thaddeus P.: 2001, Astrophys. J. 547, 792.Google Scholar
  12. Dehnen, W. and Binney, J.J.: 1998, Monthly Notices Roy. Astron. Soc. 294, 429.Google Scholar
  13. Evans, N.W.: 1994, Astrophys. J. 437, L31.Google Scholar
  14. Flynn, C. and Fuchs, B.: 1994, Monthly Notices Roy. Astron. Soc. 270, 471.Google Scholar
  15. Gerhard, O.: 2001, ‘Galaxy Disks and Disk Galaxies’in J.G., Funes and E.M., Corsini (eds.), ASP 230, 21.Google Scholar
  16. Holmberg, J. and Flynn, C.: 2000, Monthly Notices Roy. Astron. Soc. 313, 209.Google Scholar
  17. Ibata, R., Lewis, G.F., Irwin, M., Totten, E. and Quinn, T.: 2001, Astrophys. J. 294, 311.Google Scholar
  18. Kiraga, M. and Paczyński, B.: 1994, Astrophys. J. 430, L101.Google Scholar
  19. Kochanek, C.: 1996, Astrophys. J. 457, 228.Google Scholar
  20. Kuijken, K. and Gilmore, G.: 1991, Astrophys. J. 367, L9.Google Scholar
  21. Little, B. and Tremaine, S.D.: 1987, Astrophys. J. 320, 493.Google Scholar
  22. López-Corredoira, M., Hammersley, P.L., Garzón, F. et al.: 2000, Monthly Notices Roy. Astron. Soc. 313, 392.Google Scholar
  23. Ortiz, R. and Lépine, J.R.D.: 1993, Astron. Astrophys. 279, 90.Google Scholar
  24. Popowski, P. et al.: 2000, ASP, in press.Google Scholar
  25. Sackett, P.D.: 1997, Astrophys. J. 483, 103.Google Scholar
  26. Spergel, D.N., Malhotra, S. and Blitz, L.: 1996, in D. Minnii and H.-W. Rix (eds.), Spiral Galaxies in the Near-IR, Springer-Verlag, Berlin, p. 128.Google Scholar
  27. Stanek, K.Z. et al.: 1997, Astrophys. J. 477, 163.Google Scholar
  28. Udalski, A. et al.: 1994, Acta Astron. 44, 165.Google Scholar
  29. van der Marel, R.P.: 2001, astro-ph/0107248.Google Scholar
  30. Wilkinson, M.I. and Evans, N.W.: 1999, Monthly Notices Roy. Astron. Soc. 310, 645.Google Scholar
  31. Zhao, H.S. and Mao, S.: 1996, Monthly Notices Roy. Astron. Soc. 283, 1197.Google Scholar
  32. Zhao, H.S., Spergel, D.N. and Rich, R.M.: 1995, Astrophys. J. 440, L13.Google Scholar

Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Ortwin Gerhard
    • 1
  1. 1.Astronomisches InstitutUniversität BaselSwitzerland

Personalised recommendations