Biases in hydrostatic mass profiles introduced by hot gas substructures: Chandra study of four galaxy clusters

Abstract

By analyzing the azimuthal variations of total gravitating mass profiles in the central 300 h^-1₇₁ kpc regions of four galaxy clusters with Chandra data, we find that the azimuthally-averaged mass profiles may have been systematically underestimated by 16⁺⁹_-8% at 1σ significance in the 50-100 h^-1₇₁ kpc regions, probably due to the prevailing existence of 2-D hot gas substructures in 100-300 h^-1₇₁ kpc. The mass biases become negligible (-7⁺¹¹_-9 %) at > 150 h^-1₇₁ kpc. We confirm the results that the gas temperature maps can be used to probe the departure from hydrostatic equilibrium and help quantify the systematic biases in X-ray mass measurements in the central regions of clusters.