Scaling Rrelation in two situations of extreme mergers

TL;DR

This study uses numerical simulations of extreme galaxy cluster mergers to demonstrate that key X-ray scaling relations remain valid, highlighting the robustness of these relations even during highly dynamic events.

Contribution

It extends previous work by analyzing extreme merger cases through simulations, showing that scaling laws hold under such conditions and emphasizing the importance of masking procedures in X-ray temperature measurements.

Findings

Extreme mergers respect X-ray scaling relations.

Masking procedures significantly affect temperature measurements.

Mis-centering has minimal impact on results.

Abstract

Clusters of galaxies are known to be dynamically active systems, yet X-ray studies of the low redshift population exhibit tight scaling laws. In this work, we extend previous studies of this apparent paradox using numerical simulations of two extreme merger cases, one is a high Mach number (above 2.5) satellite merger similar to the "bullet cluster" and the other a merger of nearly equal mass progenitors. Creating X-ray images densely sampled in time, we construct TX, Mgas, and YX measures within R500 and compare to the calibrations of Kravtsov et al. (2006). We find that these extreme merger cases respect the scaling relations, for both intrinsic measures and for measures derived from appropriately masked, synthetic Chandra X-ray images. The masking procedure plays a critical role in the X-ray temperature calculation while it is irrelevant in the X-ray gas mass derivation. Mis-centering up to 100 kpc does not influence the result. The observationally determined radius R500 might conduce to systematic shifts in Mgas, and YX which increase the total mass scatter.