# Forming one of the most massive objects in the Universe: The quadruple merger in Abell 1758

## TL;DR

This paper investigates the complex merger dynamics of Abell 1758, revealing shock fronts, cold fronts, and radio halos through detailed X-ray and radio observations, enhancing understanding of massive cluster formation.

## Contribution

It provides the first confirmed shock front in Abell 1758's northern cluster and maps temperature, abundance, and non-thermal emissions, offering new insights into cluster merger processes.

## Key findings

- Confirmed a shock front in the northern cluster.
- Identified radio halos in both clusters.
- Detected a radio relic in the southern cluster.

## Abstract

Abell1758 is a system of two galaxy clusters, a more massive, northern cluster and a southern cluster. Both parts are undergoing major merger events at different stages. Although the mass of the merger constituents provides enough energy to produce visible shock fronts in the X-ray, none have been found to date. We present detailed temperature and abundance maps based on Chandra ACIS data, and identify several candidates for shocks and cold fronts from a smoothed gradient map of the surface brightness. One candidate can be confirmed as the missing shock front in the northern cluster through X-ray spectroscopy. Non-thermal radio emission observed with the GMRT confirms the presence of radio halos in the northern and southern clusters, and shows evidence for a relic in the periphery of the southern cluster. We do not find evidence for shocked gas between A1758N and A1758S.