The MUSIC of galaxy clusters – II. X-ray global properties and scaling relations

Abstract

We present the X-ray properties and scaling relations of a large sample of clusters extracted from the Marenostrum MUltidark SImulations of galaxy Clusters (MUSIC) data set. We focus on a sub-sample of 179 clusters at redshift z 0.11, with 3.2 10 14 h -1 M < M vir < 2 10 15 h -1 M , complete in mass. We employed the X-ray photon simulator PHOX to obtain synthetic Chandra observations and derive observable-like global properties of the intracluster medium (ICM), as X-ray temperature (T X ) and luminosity (L X ). T X is found to slightly underestimate the true mass-weighted temperature, although tracing fairly well the cluster total mass. We also study the effects of T X on scaling relations with cluster intrinsic properties: total (M 500 and gas M g,500 mass; integrated Compton parameter (Y SZ ) of the Sunyaev-Zel'dovich (SZ) thermal effect; Y X = M g,500 T X . We confirm that Y X is a very good mass proxy, with a scatter on M 500 -Y X and Y SZ -Y X lower than 5 per cent. The study of scaling relations among X-ray, intrinsic and SZ properties indicates that simulated MUSIC clusters reasonably resemble the self-similar prediction, especially for correlations involving T X . The observational approach also allows for a more direct comparison with real clusters, from which we find deviations mainly due to the physical description of the ICM, affecting T X and, particularly, L X .