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The UV-upturn in brightest cluster galaxies

Published online by Cambridge University Press:  05 March 2015

S. I. Loubser
Affiliation:
Centre for Space Research, North-West University, Potchefstroom 2520, South Africa email: [email protected]
P. Sánchez-Blázquez
Affiliation:
Departamento de Física Teórica, Universidad Autónoma de Madrid, E28049, Spain email: [email protected]
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Abstract

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This study is part of a series devoted to the investigation of a large sample of brightest cluster galaxies (BCGs), their properties and the relationships between these and the properties of the host clusters. In this paper, we compare the stellar population properties derived from high signal-to-noise, optical long-slit spectra with the GALEX ultraviolet (UV) colour measurements for 36 nearby BCGs to understand the diversity in the most rapidly evolving feature in old stellar systems, the UV-upturn. We investigate: (1) the possible differences between the UV-upturn of BCGs and those of a control sample of ordinary ellipticals in the same mass range, as well as possible correlations between the UV-upturn and other general properties of the galaxies; (2) possible correlations between the UV-upturn and the properties of the host clusters; (3) recently proposed scenarios where helium-sedimentation in the cluster centre can produce an enhanced UV-upturn. We find systematic differences between the UV-colours of BCGs and ordinary ellipticals, but we do not find correlations between these colours and the properties of the host clusters. Furthermore, the observations do not support the predictions made by the helium-sedimentation model as an enhancer of the UV-upturn.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2015 

References

Loubser, S. I. & Sánchez-Blázquez, P 2011, MNRAS, 410, 2679Google Scholar