Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/37196

Download PDF (Author's final draft) (Adobe Acrobat PDF, -1 bytes)

Title

Spatially resolved kinematics and stellar populations of brightest cluster and group galaxies

Author(s)

Brough, Sarah;  Proctor, Robert N.;  Forbes, Duncan A.;  Couch, Warrick J.;  Collins, Chris A.;  Burke, Douglas J.;  Mann, Robert G.

Abstract

We present an examination of the kinematics and stellar populations of a sample of three brightest group galaxies (BGGs) and three brightest cluster galaxies (BCGs) in X-ray groups and clusters. We have obtained high signal-to-noise ratio Gemini/Gemini South Multi-Object Spectrograph (GMOS) long-slit spectra of these galaxies and use Lick indices to determine ages, metallicities and alpha-element abundance ratios out to at least their effective radii. We find that the BGGs and BCGs have very uniform masses, central ages and central metallicities. Examining the radial dependence of their stellar populations, we find no significant velocity dispersion, age, or alpha-enhancement gradients. However, we find a wide range of metallicity gradients, suggesting a variety of formation mechanisms. The range of metallicity gradients observed is surprising, given the homogeneous environment these galaxies probe and their uniform central stellar populations. However, our results are inconsistent with any single model of galaxy formation and emphasize the need for more theoretical understanding of both the origins of metallicity gradients and galaxy formation itself. We postulate two possible physical causes for the different formation mechanisms.

Publication type

Journal article

Research centre

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

Source

Monthly Notices of the Royal Astronomical Society, Vol. 378, no. 4 (Jun 2007), p. 1507-1530

Publication year

2007

Keyword(s)

BCGs;  BGGs;  Brightest cluster galaxies;  Brightest group galaxies;  cD;  Clusters;  Elliptical galaxies;  Galaxy evolution;  Galaxy formation;  Gemini/Gemini South Multi-Object Spectrograph;  GMOS;  Lenticular galaxies

Publisher

Blackwell Publishing

ISSN

0035-8711

Publisher URL

http://dx.doi.org/10.1111/j.1365-2966.2007.11900.x

Copyright

Copyright © 2007 Royal Astronomical Society. Author's final draft reproduced here in accordance with the copyright policy of the publisher.

Full text

Peer reviewed