Calibration of the galaxy cluster <i>M</i>₅₀₀–<i>Y</i>$_{\sf X}$ relation with XMM-Newton

Abstract

The quantity Y_ X, the product of the X-ray temperature T_ X and gas mass M_ g, has recently been proposed as a robust low-scatter mass indicator for galaxy clusters. Using precise measurements from XMM-Newton data of a sample of 10 relaxed nearby clusters, spanning a Y_ X range of 10^13 -10^15 M_sun keV, we investigate the M_500-Y_ X relation. The M_500 - Y_ X data exhibit a power law relation with slope alpha=0.548 \pm 0.027, close to the self-similar value (3/5) and independent of the mass range considered. However, the normalisation is \sim 20% below the prediction from numerical simulations including cooling and galaxy feedback. We discuss two effects that could contribute to the normalisation offset: an underestimate of the true mass due to the HE assumption used in X-ray mass estimates, and an underestimate of the hot gas mass fraction in the simulations. A comparison of the functional form and scatter of the relations between various observables and the mass suggest that Y_ X may indeed be a better mass proxy than T_ X or M_g,500.

Keywords

Affiliated Institutions

• Centre National de la Recherche Scientifique FR
• Université Paris Cité FR
• Laboratoire d'Analyse et d'Architecture des Systèmes FR
• Astrophysique, Instrumentation et Modélisation FR
• Roche (France) FR
• Max Planck Society DE
• Max Planck Institute for Extraterrestrial Physics DE
• CEA Paris-Saclay FR
• Commissariat à l'Énergie Atomique et aux Énergies Alternatives FR

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