A Universal Temperature Profile for Galaxy Clusters

C. Loken; M. L. Norman; E. Nelson; J. Burns; G. L. Bryan; P. Motl

doi:10.1086/342825

paper

A Universal Temperature Profile for Galaxy Clusters

arXiv:astro-ph/0207095 · doi:10.1086/342825

Abstract

We investigate the predicted present-day temperature profiles of the hot, X-ray emitting gas in galaxy clusters for two cosmological models - a current best-guess LCDM model and standard cold dark matter (SCDM). Our numerically-simulated "catalogs" of clusters are derived from high-resolution (15/h kpc) simulations which make use of a sophisticated, Eulerian-based, Adaptive Mesh-Refinement (AMR) code that faithfully captures the shocks which are essential for correctly modelling cluster temperatures. We show that the temperature structure on Mpc-scales is highly complex and non-isothermal. However, the temperature profiles of the simulated LCDM and SCDM clusters are remarkably similar and drop-off as $T + A F w - p r o pt o (1 + - r / a_{x})^{-+ A F w - d e l t a}$ where $a_{x} + A F w - s im r_{v i r} /1.5$ and $+ A F w - d e l t a + A F w - s im 1.6$ . This decrease is in good agreement with the observational results of Markevitch et al.(1998) but diverges, primarily in the innermost regions, from their fit which assumes a polytropic equation of state. Our result is also in good agreement with a recent sample of clusters observed by BeppoSAX though there is some indication of missing physics at small radii ( $r < 0.2 r_{v i r}$ ). We discuss the interpretation of our results and make predictions for new x-ray observations that will extend to larger radii than previously possible. Finally, we show that, for $r > 0.2 r_{v i r}$ , our universal temperature profile is consistent with our most recent simulations which include both radiative cooling and supernovae feedback.

8 pages, 6 figures, accepted for publication in ApJ, full-page version of Fig. 2 at http://www.cita.utoronto.ca/+AH4-cloken/PAPERS/UTP/f2.eps

A Universal Temperature Profile for Galaxy Clusters

Abstract

Cited by in corpus (95)