Investigating the star formation histories of the brightest cluster galaxies
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Date
Authors
Groenewald, D.N.
Loubser, S.I.
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Journal ISSN
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Publisher
Oxford Univ Press
Abstract
This article is devoted to the study of the central stellar populations of the brightest cluster
galaxies (BCGs). High signal-to-noise ratio, long-slit spectra for a sample of 39 galaxies
were fitted against two stellar population models, Pegase.HR (P.HR) and Vazdekis/MILES, to
determine the star formation histories of the galaxies using full spectrum fitting, to investigate,
in particular, whether a single stellar population (SSP) or composite stellar population model
provides the better description. Monte Carlo simulations and χ2 maps were used to check the
reliability of the solutions. The ages and [Fe/H] were (i) compared with those derived with
the Lick indices and (ii) tested against the internal galaxy properties (the velocity dispersions
and absolute K-band magnitudes) and the properties of the host cluster environment (X-ray
temperatures, luminosities, offsets and the presence of cooling flows (CFs)), to determine
whether any statistically significant correlations existed. The results indicate that 79 per cent
of the BCG sample could be represented by an SSP fit, while the remaining 21 per cent likely
experienced more than one star formation epoch. The correlations showed that the BCGs
hosted in CF clusters are generally found closer to the centre of the clusters, while the BCGs
in non-CF clusters are generally found further away. The main results suggested that at least
some of the galaxies in the BCG sample had a more complex star formation history than first
assumed and that the presence of CFs in the clusters could account for some, but not all, of
the star formation activity of BCGs
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Citation
Groenewald, D.N. & Loubser, S.I. 2014. Investigating the star formation histories of the brightest cluster galaxies. Monthly notices of the Royal Astronomical Society, 444(1):808-826. [https://doi.org/10.1093/mnras/stu1319]