Limits on the dark matter content of globular clusters

Baumgardt, H., Côté, P., Hilker, M., Rejkuba, M., Mieske, S., Djorgovski, S. G. and Stetson, P. (2009). Limits on the dark matter content of globular clusters. In: Richard de Grijs and Jacques Lépine, Star clusters: Basic galactic building blocks throughout time and space. IAU Symposium 266. Star Clusters: Basic Galactic Building Blocks Throughout Time And Space, Rio de Janeiro, Brazil, (365-365). 10-14 August 2009. doi:10.1017/S174392130999130X


Author Baumgardt, H.
Côté, P.
Hilker, M.
Rejkuba, M.
Mieske, S.
Djorgovski, S. G.
Stetson, P.
Title of paper Limits on the dark matter content of globular clusters
Conference name IAU Symposium 266. Star Clusters: Basic Galactic Building Blocks Throughout Time And Space
Conference location Rio de Janeiro, Brazil
Conference dates 10-14 August 2009
Proceedings title Star clusters: Basic galactic building blocks throughout time and space   Check publisher's open access policy
Journal name Proceedings of the International Astronomical Union   Check publisher's open access policy
Place of Publication Cambridge, U.K.
Publisher Cambridge University Press
Publication Year 2009
Sub-type Published abstract
DOI 10.1017/S174392130999130X
Open Access Status
ISBN 9780521764995
0521764998
ISSN 1743-9213
1743-9221
Editor Richard de Grijs
Jacques Lépine
Volume 5
Issue S266
Start page 365
End page 365
Total pages 1
Language eng
Formatted Abstract/Summary
We have measured the velocity dispersion of the Galactic globular cluster NGC 2419 to determine if a substantial amount of dark matter is present in this cluster. NGC 2419 is one of the best globular clusters to look for dark matter due to its large mass, long relaxation time and large Galactocentric distance, which makes tidal stripping of dark matter unlikely. Our results can be summarized as follows. (i) We found a global velocity dispersion of 4.14 ± 0.48 km s−1, which leads to a total cluster mass of (9.02 ± 2.22) × 105 M and implies a global mass-to-light ratio of 2.05 ± 0.50 M/L. (ii) Our derived mass-to-light ratio is completely consistent with the mass-to-light ratio of a standard stellar population at the metallicity and age of NGC 2419. In addition, the mass-to-light ratio of NGC 2419 does not increase towards the outer cluster parts. (iii) We can therefore rule out the presence of a dark-matter halo with a central density greater than about 0.02 M pc−3. Similar limits are found for other halo globular clusters, like Pal 14. These observations therefore indicate that NGC 2419 and other halo globular clusters did not form at the centers of dark-matter halos similar to those surrounding dwarf galaxies. Instead, an origin driven by gas-dynamical processes during mergers between galaxies or proto-galactic fragments seems to be the more likely explanation for the formation of even the lowest-metallicity globular clusters.
Keyword Globular clusters: individual (NGC 2419)
Dark matter
Q-Index Code EX
Q-Index Status Provisional Code
Institutional Status Non-UQ
Additional Notes Publication date: 01 Aug 2009.

Document type: Conference Paper
Collections: School of Mathematics and Physics
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