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Title

Extragalactic globular clusters: unraveling galaxy formation and constraining stellar evolution theories

Author(s)

Cenarro, A. Javier;  Beasley, Michael A.;  Strader, Jay;  Brodie, Jean P.;  Forbes, Duncan A.

Abstract

Understanding the stellar populations of extragalactic globular cluster (GC) systems and, in particular, determining their ages, provide essential clues to constrain the star formation histories of their host galaxies. We here summarize the most relevant results derived from a detailed, spectroscopic study of 20 GCs in the E0 NGC 1407. We find most GCs are old (~11 Gyr), follow a tight metallicity sequence reaching values slightly above solar, and exhibit mean [α/Fe] ratios of ~0.3 dex. Blue horizontal branch effects are detected for 3 GCs. We also report the existence of two families of metal-rich (MR) GCs, as some of them exhibit significantly larger [Mg/Fe] and [C/Fe] ratios, what might be interpreted in terms of different star formation time-scales. Striking CN overabundances are found over the entire GC metallicity range. In particular, for MR GCs, N increases dramatically while C essentially saturates. This may be interpreted as a consequence of the increasing importance of the CNO cycle with increasing metallicity.

Publication type

Conference paper

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Proceedings of the International Astronomical Union Symposium S241: Stellar Populations as Building Blocks of Galaxies, La Palma, Canary Islands, Spain, 10-14 December 2006 / Alexandre Vazdekis and Reynier Peletier (eds.), Vol. 2, pp. 445-448

Publication year

2007

Keyword(s)

Galaxy formation;  GCs;  Globular clusters

Publisher

Cambridge University Press

ISBN

0521333801

Publisher URL

http://dx.doi.org/10.1017/S1743921307008721

Copyright

Copyright © International Astronomical Union 2007. Published version of the paper reproduced here in accordance with the copyright policy of the publisher.

Full text

Peer reviewed