Pointing to the minimum scatter: the generalized scaling relations for galaxy clusters

Abstract

We introduce a generalized scaling law, M_tot = 10^K A^a B^b, to look for the minimum scatter in reconstructing the total mass of hydrodynamically simulated X-ray galaxy clusters, given gas mass M_gas, luminosity L and temperature T. We find a locus in the plane of the logarithmic slopes $a$ and $b$ of the scaling relations where the scatter in mass is minimized. This locus corresponds to b_M = -3/2 a_M +3/2 and b_L = -2 a_L +3/2 for A=M_gas and L, respectively, and B=T. Along these axes, all the known scaling relations can be identified (at different levels of scatter), plus a new one defined as M_tot ~ (LT)^(1/2). Simple formula to evaluate the expected evolution with redshift in the self-similar scenario are provided. In this scenario, no evolution of the scaling relations is predicted for the cases (b_M=0, a_M=1) and (b_L=7/2, a_L=-1), respectively. Once the single quantities are normalized to the average values of the sample under considerations, the normalizations K corresponding to the region with minimum scatter are very close to zero. The combination of these relations allows to reduce the number of free parameters of the fitting function that relates X-ray observables to the total mass and includes the self-similar redshift evolution.

6 pages, 3 figures. MNRAS in press

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Cited by in corpus (10)

• Scaling relations for galaxy clusters: properties and evolution
• Cosmological hydrodynamical simulations of galaxy clusters: X-ray scaling relations and their evolution
• The physics inside the scaling relations for X-ray galaxy clusters: gas clumpiness, gas mass fraction and slope of the pressure profile
• CoMaLit-V. Mass forecasting with proxies. Method and application to weak lensing calibrated samples
• The MUSIC of Galaxy Clusters II: X-ray global properties and scaling relations
• The generalized scaling relations for X-ray galaxy clusters: the most powerful mass proxy
• Center-Excised X-ray Luminosity as an Efficient Mass Proxy for Future Galaxy Cluster Surveys
• RHAPSODY-G simulations II - Baryonic growth and metal enrichment in massive galaxy clusters
• Evaluating Tests of Virialization and Substructure Using Galaxy Clusters in the ORELSE Survey
• Scaling relations of clusters and groups, and their evolution