Cluster Geometry & Inclinations from Deprojection Uncertainties

TL;DR

This paper presents a method to determine the intrinsic shape and orientation of galaxy clusters by comparing deprojected X-ray profiles under different geometries and inclinations, enhanced by SZe data, to better estimate cluster masses.

Contribution

It introduces a novel scheme combining multiple deprojection assumptions and SZe data to identify cluster morphology and inclination, improving mass estimation accuracy.

Findings

Identified 8 prolate, 1 oblate, and 15 triaxial clusters.

Successfully constrained the inclination and intrinsic axial ratios of triaxial clusters.

Demonstrated the method's effectiveness with a sample of 24 galaxy clusters.

Abstract

{The determination of cluster masses is a complex problem that would be aided by information about the cluster shape and orientation (along the line-of-sight).} {It is in this context, that we have developed a scheme for identifying the intrinsic morphology and inclination of a cluster, by looking for the signature of the true cluster characteristics in the inter-comparison of the different deprojected emissivity profiles (that all project to the same X-ray brightness distribution) and by using SZe data when available.} {We deproject the cluster X-ray surface brightness profile under the assumptions of four different geometry and inclination configurations for the observed system; these 4 configurations correspond to four extreme geometry+inclination scenarios. The deprojection in question is performed by the non-parametric algorithm DOPING. The formalism is tested with model systems and then is applied to a sample of 24 clusters. While the shape determination is possible by implementing the X-ray brightness alone, the estimation of the inclination is usually markedly improved by the usage of SZe data that is available for the considered sample.}{We spot 8 prolate systems, 1 oblate and 15 of the clusters in our sample as triaxial. In fact, for systems identified as triaxial, we are able to discern how the three semi-axes lengths compare with each other. This, when compounded by the information about the line-of-sight extent, allows us to constrain the inclination quite tightly and offers the two intrinsic axial ratios of the triaxial systems.}{}