Extragalactic magnetic fields and nonthermal components

Radio emission (blue) from the bridge connecting the galaxy clusters A399 and A401 (in the insets) superimposed onto the cluster gas emission (red). Credits: https://science.sciencemag.org/content/364/6444/981

As a result of violent processes following their evolution, galaxy clusters and large scale structures in general contain a significant fraction of nonthermal energy, in the form of magnetic fields, relativistic particles and turbulent plasma motions.  Radio observations of diffuse emission (e.g. “halos”, “relics” and “mini-halos” sources) in galaxy clusters is vital  to constrain the acceleration mechanisms of relativistic particles during accretion phenomena, as well as the origin of extragalactic magnetic fields, which is still a mystery. In addition to matter accretions, the “radio-mode” feedback from AGN, associated to the complex interplay between hot intra-cluster medium and cold molecular gas in galaxies, is widespread and has a broad impact from the formation of galaxies to the regulation of cool cores, and may spread relativistic particles and magnetic fields on cluster-scale.

Our team is deeply involved in both the observational and theoretical work necessary to study the elusive non-thermal radio signal from evolving cosmic structures, both by conducting new observations of cosmic structures at radio wavelengths (e.g. with JVLA, LOFAR, GMRT etc..), complemented by multi-frequency observations (from X-rays with CHANDRA and XMM to sub-mm wavelenghts using  ALMA), as well as by preparing for the Square Kilometer Array (SKA) and investigating the origin of extragalactic magnetic fields with advanced cosmological simulations (see here).

Funding

• ERC Grants no. 714196 “MAGCOW”
• ERC Grants no. 714245 “DRANOEL”