Hostname: page-component-586b7cd67f-r5fsc Total loading time: 0 Render date: 2024-11-28T22:41:50.706Z Has data issue: false hasContentIssue false
  • English
  • Français

Kinematics of Globular Clusters in M49 and M87

Published online by Cambridge University Press:  03 August 2017

Terry Bridges
Terry Bridges*
Affiliation:
Anglo-Australian Observatory, P.O. Box 296, Epping, NSW, Australia

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We present recent multi-object spectroscopy of globular clusters in the Virgo gEs M49 and M87. In M49, we have a total of 144 confirmed clusters out to 8 arcmin radius (∼ 6 Reff or 35 kpc). We find that the blue (metal-poor) clusters have both a higher velocity dispersion and rotation than the red (metal-poor) clusters. For the metal-rich population we place an upper limit of (v/σ)proj < 0.34 at 99% confidence. We calculate the velocity dispersion as a function of radius, and show that this is consistent with isotropic cluster orbits and the M49 mass distribution determined from X-ray data. For M87, we combine new CFHT data with previous data to obtain a total sample of 278 clusters out to 10 arcmin radius (∼ 45 kpc). We find a similar global rotation for the metal-poor and metal-rich clusters of 160–170 km/sec. Beyond ⋍ 2 Reff (15 kpc), both the metal-poor and metal-rich clusters appear to rotate about the photometric minor axis. The combined cluster sample is consistent with isotropic orbits, but when considered separately, the metal-poor clusters show significant tangential bias of βcl ⋍ −0.4, while the metal-rich clusters show a radial bias with βcl ⋍ +0.4. In both galaxies, the metal-rich and metal-poor clusters share different kinematics, but there is no clear preference for any one formation scenario.

Type
Part 2. Globular Cluster Systems of Distant Galaxies
Information
Symposium - International Astronomical Union , Volume 207: Extragalactic Star Clusters , 2002 , pp. 256 - 262
Copyright
Copyright © Astronomical Society of the Pacific 2002 

References

Ashman, K.M., & Zepf, S.E. 1992, ApJ, 384, 50 CrossRefGoogle Scholar
Beasley, M.A., Sharpies, R.M., Bridges, T.J., Hanes, D.A., Zepf, S.E., Ashman, K.M., & Geisler, D. 2000, MNRAS, 318, 1249 CrossRefGoogle Scholar
Cohen, J.G., & Ryzhov, A. 1997, ApJ, 486, 230 CrossRefGoogle Scholar
Côtê, P., Marzke, R.O., & West, M.J. 1998, 501, 554 CrossRefGoogle Scholar
Côté, P., McLaughlin, D.E., Hanes, D.A., Bridges, T.J., Geisler, D., Merritt, D., Hesser, J.E., Harris, G.L.H., & Lee, M.G. 2001, ApJ, in press (astroph 0106005) Google Scholar
Forbes, D.A., Brodie, J.P., & Grillmair, C.J. 1997, AJ, 113, 1652 CrossRefGoogle Scholar
Geisler, D., Lee, M.G., & Kim, E. 1996, AJ, 111, 1529 CrossRefGoogle Scholar
Geisler, D., Lee, M.G., & Kim, E. 2001, in preparation Google Scholar
Hanes, D.A., Côté, P., Bridges, T.J., McLaughlin, D.E., Geisler, D., Harris, G.L.H., Hesser, J.E., & Lee, M.G. 2001, ApJ, in press (astroph 0106004) Google Scholar
Irwin, J.A., & Sarazin, C.L. 1996, ApJ, 471, 683 CrossRefGoogle Scholar
McLaughlin, D.E. 1999, ApJ, 512, L9 CrossRefGoogle Scholar
Mould, J.R., Oke, J.B., de Zeeuw, P.T., & Nemec, J. 1990, AJ, 99, 1823 CrossRefGoogle Scholar
Schweizer, F. 1987, in Nearly Normal Galaxies, (New York: Springer-Verlag), 18 CrossRefGoogle Scholar
Sharpies, R.M., Zepf, S.E., Bridges, T.J., Hanes, D.A., Carter, D., Ashman, K.M., & Geisler, D. 1998, AJ, 115, 2337 CrossRefGoogle Scholar
Zepf, S.E., Beasley, M.A., Bridges, T.J., Hanes, D.A., Sharpies, R.M., Ashman, K.M., & Geisler, D. 2000, AJ, 120, 2928 CrossRefGoogle Scholar