The Sunyaev–Zel'dovich temperature of the intracluster medium |
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| Authors: | Scott T Kay Leila C Powell rew R Liddle Peter A Thomas |
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| Institution: | Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL;Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH;Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH |
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| Abstract: | The relativistic Sunyaev–Zel'dovich (SZ) effect offers a method, independent of X-ray, for measuring the temperature of the intracluster medium (ICM) in the hottest systems. Here, using N -body/hydrodynamic simulations of three galaxy clusters, we compare the two quantities for a non-radiative ICM, and for one that is subject both to radiative cooling and to strong energy feedback from galaxies. Our study has yielded two interesting results. First, in all cases, the SZ temperature is hotter than the X-ray temperature and is within 10 per cent of the virial temperature of the cluster. Secondly, the mean SZ temperature is less affected by cooling and feedback than the X-ray temperature. Both these results can be explained by the SZ temperature being less sensitive to the distribution of cool gas associated with cluster substructure. A comparison of the SZ and X-ray temperatures (measured for a sample of hot clusters) would therefore yield interesting constraints on the thermodynamic structure of the intracluster gas. |
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| Keywords: | hydrodynamics methods: numerical X-rays: galaxies: clusters |
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