Massive merging cluster PSZ2G091 as seen by the NIKA2 camera

TL;DR

This study uses high-resolution NIKA2 observations to analyze the complex, bimodal morphology of the galaxy cluster PSZ2G091, highlighting the importance of accounting for cluster morphology in thermodynamical measurements.

Contribution

It introduces a two-halo model fitting approach to better characterize complex cluster morphologies in high-redshift galaxy clusters.

Findings

The two-halo model reveals significant deviations from the spherical assumption.

Morphological complexity impacts pressure profile estimates.

High-resolution data improves cluster modeling accuracy.

Abstract

PSZ2 G091.83+26.11 is a galaxy cluster with M500 = 7.43 x 10^14 Msun at z = 0.822 1. This object exhibits a complex morphology with a clear bimodality observed in X-rays. However, it was detected and analysed in the Planck sample as a single, spherical cluster following a universal profile 2. This model can lead to miscalculations of thermodynamical quantities, like the pressure profile. As future multiwavelength cluster experiments will detect more and more objects at high redshifts, it is crucial to quantify this systematic effect. In this work, we use high-resolution observations of the NIKA2 camera3,4,5,6 to integrate the morphological characteristics of the cluster in our modelling. This is achieved by fitting a two-halo model to the SZ image and then by reconstruction of the resulting projected pressure profile. We then compare these results with the spherical assumption.