HIFLUGCS: Galaxy cluster scaling relations between X-ray luminosity, gas mass, cluster radius, and velocity dispersion^⋆

¹ Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
e-mail: yyzhang@astro.uni-bonn.de
² National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, PR China
³ Departamento de Astronomía, Universidad de Guanajuato, AP 144, Guanajuato CP 36000, Mexico
⁴ Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany
⁵ Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Straße 1, 85741 Garching, Germany
⁶ Kavli Institute for Cosmology, Cambridge and Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA, UK
⁷ Dipartimento di Fisica dell’ Universitá degli Studi di Trieste Sezione di Astronomia, via Tiepolo 11, 34143 Trieste, Italy
⁸ INAF Osservatorio Astronomico di Trieste, via Tiepolo 11, 34143 Trieste, Italy

Received: 28 September 2010
Accepted: 10 November 2010

Abstract

We present relations between X-ray luminosity and velocity dispersion (L − σ), X-ray luminosity and gas mass (L − M_gas), and cluster radius and velocity dispersion (r₅₀₀ − σ) for 62 galaxy  clusters in the HIFLUGCS, an X-ray flux-limited sample minimizing bias toward any cluster morphology. Our analysis in total is based on  ~1.3 Ms of clean X-ray XMM-Newton data and 13439 cluster member galaxies with redshifts. Cool cores are among the major contributors to the scatter in the L − σ relation. When the cool-core-corrected X-ray luminosity is used the intrinsic scatter decreases to 0.27 dex. Even after the X-ray luminosity is corrected for the cool core, the scatter caused by the presence of cool cores dominates for the low-mass systems. The scatter caused by the non-cool-core clusters does not strongly depend on the mass range, and becomes dominant in the high-mass regime. The observed L − σ relation agrees with the self-similar prediction, matches that of a simulated sample with AGN feedback disregarding six clusters with  <45 cluster members with spectroscopic redshifts, and shows a common trend of increasing scatter toward the low-mass end, i.e., systems with σ ≤ 500   kms^-1. A comparison of observations with simulations indicates an AGN-feedback-driven impact in the low-mass regime. The best fits to the L − M_gas relations for the disturbed clusters and undisturbed clusters in the observational sample closely match those of the simulated samples with and without AGN feedback, respectively. This suggests that one main cause of the scatter is AGN activity providing feedback in different phases, e.g. during a feedback cycle. The slope and scatter in the observed r₅₀₀ − σ relation is similar to that of the simulated sample with AGN feedback except for a small offset but still within the scatter.