# A radio ridge connecting two galaxy clusters in a filament of the cosmic web

## TL;DR

This paper reports the discovery of a radio-emitting filament connecting two galaxy clusters, suggesting re-acceleration of particles by weak shocks in the cosmic web's filamentary structure.

## Contribution

It presents the first observation of a radio ridge linking galaxy clusters and demonstrates the role of weak shocks in particle re-acceleration within cosmic filaments.

## Key findings

- Radio emission connects galaxy clusters Abell 0399 and Abell 0401.
- Weak shocks can re-accelerate relativistic particles in cosmic filaments.
- Magnetic fields and relativistic electrons are present in the filament.

## Abstract

Galaxy clusters are the most massive gravitationally bound structures in the Universe. They grow by accreting smaller structures in a merging process that produces shocks and turbulence in the intra-cluster gas. We observed a ridge of radio emission connecting the merging galaxy clusters Abell 0399 and Abell 0401 with the Low Frequency Array (LOFAR) at 140 MHz. This emission requires a population of relativistic electrons and a magnetic field located in a filament between the two galaxy clusters. We performed simulations to show that a volume-filling distribution of weak shocks may re-accelerate a pre-existing population of relativistic particles, producing emission at radio wavelengths that illuminates the magnetic ridge.

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Source: https://tomesphere.com/paper/1906.07584