English

Hydrostatic mass profiles in X-COP galaxy clusters

Cosmology and Nongalactic Astrophysics 2019-01-09 v3

Abstract

We present the reconstruction of hydrostatic mass profiles in 13 X-ray luminous galaxy clusters that have been mapped in their X-ray and SZ signal out to R200R_{200} for the XMM-Newton Cluster Outskirts Project (X-COP). Using profiles of the gas temperature, density and pressure that have been spatially resolved out to (median value) 0.9 R500R_{500}, 1.8 R500R_{500}, and 2.3 R500R_{500}, respectively, we are able to recover the hydrostatic gravitating mass profile with several methods and using different mass models. The hydrostatic masses are recovered with a relative (statistical) median error of 3% at R500R_{500} and 6% at R200R_{200}. By using several different methods to solve the equation of the hydrostatic equilibrium, we evaluate some of the systematic uncertainties to be of the order of 5% at both R500R_{500} and R200R_{200}. A Navarro-Frenk-White profile provides the best-fit in nine cases out of 13, with the remaining four cases that do not show a statistically significant tension with it. The distribution of the mass concentration follows the correlations with the total mass predicted from numerical simulations with a scatter of 0.18 dex, with an intrinsic scatter on the hydrostatic masses of 0.15 dex. We compare them with the estimates of the total gravitational mass obtained through X-ray scaling relations applied to YXY_X, gas fraction and YSZY_{SZ}, and from weak lensing and galaxy dynamics techniques, and measure a substantial agreement with the results from scaling laws, from WL at both R500R_{500} and R200R_{200} (with differences below 15%), from cluster velocity dispersions, but a significant tension with the caustic masses that tend to underestimate the hydrostatic masses by 40% at R200R_{200}. We also compare these measurements with predictions from alternative models to the Cold Dark Matter, like the "Emergent Gravity" and MOND scenarios.

Keywords

Cite

@article{arxiv.1805.00035,
  title  = {Hydrostatic mass profiles in X-COP galaxy clusters},
  author = {S. Ettori and V. Ghirardini and D. Eckert and E. Pointecouteau and F. Gastaldello and M. Sereno and M. Gaspari and S. Ghizzardi and M. Roncarelli and M. Rossetti},
  journal= {arXiv preprint arXiv:1805.00035},
  year   = {2019}
}

Comments

14 pages, 8 figures, 4 tables. Updated to match the version accepted for publication in A&A. This is one of the three companion papers (including Ghirardini et al. and Eckert et al.) on the X-COP sample. X-COP data products are available for download on https://www.astro.unige.ch/xcop

R2 v1 2026-06-23T01:40:33.914Z