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Title

The anatomy of the NGC 5044 group II: stellar populations and star-formation histories

Author(s)

Mendel, J. Trevor;  Proctor, Robert N.;  Rasmussen, Jesper;  Brough, Sarah;  Forbes, Duncan A.

Abstract

The distribution of galaxy properties in groups and clusters holds important information on galaxy evolution and growth of structure in the Universe. While clusters have received appreciable attention in this regard, the role of groups as fundamental to formation of the present-day galaxy population has remained relatively unaddressed. Here, we present stellar ages, metallicities and α-element abundances derived using Lick indices for 67 spectroscopically confirmed members of the NGC 5044 galaxy group with the aim of shedding light on galaxy evolution in the context of the group environment. We find that galaxies in the NGC 5044 group show evidence for a strong relationship between stellar mass and metallicity, consistent with their counterparts in both higher and lower mass groups and clusters. Galaxies show no clear trend of age or α-element abundance with mass, but these data form a tight sequence when fitted simultaneously in age, metallicity and stellar mass. In the context of the group environment, our data support the tidal disruption of low-mass galaxies at small group-centric radii, as evident from an apparent lack of galaxies below ∼109 M⊙ within ∼100 kpc of the brightest group galaxy. Using a joint analysis of absorption- and emission-line metallicities, we are able to show that the star-forming galaxy population in the NGC 5044 group appears to require gas removal to explain the ∼1.5 dex offset between absorption- and emission-line metallicities observed in some cases. A comparison with other stellar population properties suggests that this gas removal is dominated by galaxy interactions with the hot intragroup medium.

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. 396, no. 4 (Jul 2009), pp. 2103-2123

Publication year

2009

FOR Code(s)

0201 Astronomical and Space Sciences;  020103 Cosmology and Extragalactic Astronomy

Keyword(s)

Distances;  Fundamental parameters of galaxies;  Galaxy clusters;  Galaxy evolution;  Galaxy formation;  NGC 5044 group;  Redshifts

Publisher

Wiley-Blackwell

ISSN

0035-8711

Publisher URL

http://dx.doi.org/10.1111/j.1365-2966.2009.14689.x

Copyright

Copyright © 2009 The Authors. Journal compilation copyright © 2009 Royal Astronomical Society. Author version reproduced here in accordance with the copyright policy of the publisher. The definitive version is available at www.interscience.wiley.com.

Additional information

This publication makes use of data products from the 2MASS, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. The authors also thank the Australian Research Council for funding that supported this work.

Full text

Peer reviewed