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Department of Physics and Astronomy “Augusto Righi” – DIFA

Clusters of galaxies: gas thermodynamics, magnetic fields and relativistic particles

Areas: Astrophysics
Radio emissions in evolving clusters of galaxies
Top: radio emission in between clusters A2061 e A2067 (Credits: Pignataro et al. 2024). Bottom: the Phoenix cluster of galaxies observed in X-rays (Chandra), radio (VLA) and optical frequencies (HST). Credits: NASA/STScI

Galaxy clusters and the cosmic web contain"non-thermal" energy, i.e. in the form of magnetic fields, relativistic particles and kinetic energy of  turbulent or regular  motions of the plasma.

Radio observations show a variety of structures:   "halos", "relics", "mini-halos" e "mega-halos" , all fundamental to understand the mechanisms of acceleration of relativistic particles.

More peripheral structures, such as "bridges" between galaxy clusters, are fundamental to the study of the plasma before its accretion. Recent observations have also revealed magnetic field in  filaments of galaxies,   which may clarify the origin of the magnetic field in the Universe.

 
The mechanical feedback from AGN  modifies the gas  thermodynamics, balancing the effect of X-ray energy radiation,  mixing the gas in the densest regions and transporting relativistic particles and magnetic fields over the cluster.


We study and observe the evolution of cosmic structures and of  their magnetic field, combining advanced cosmological simulations (produced for example at CINECA ) with observations from radio (for example with JVLA, LOFAR, uGMRT, MeerKAT, ASKAP), to microwaves (for example with ALMA) up to the highest frequencies (in X-rays with Chandra, XMM and XRISM), also in preparation for the advent of the Square Kilometre Array (SKA), the largest telescope ever built by humanity.

Main Collaborations