In order to detect the gamma-ray emission from cosmic ray (CR) interactions with the intra-cluster medium, the ground-based imaging Cherenkov telescope MAGIC conducted the deepest-to-date observational campaign targeting a galaxy cluster at very high-energies (> 100 GeV) and observed the Perseus cluster for a total of 85 hr during 2009-2011. The observations constrain the average CR-to-thermal pressure ratio to be 1-2% and the maximum CR acceleration efficiency at structure formation shocks to be <50%. Alternatively, this may argue for non-negligible CR transport processes such as CR streaming and diffusion into the outer cluster regions. Additionally, assuming that the Perseus radio mini-halo is generated by secondaries created in hadronic CR interactions, the central magnetic field is limited to be > 4-9 muG. This range is well below the field strength inferred from Faraday rotation measurements and, therefore, the hadronic model remains a plausible explanation of the Perseus radio mini-halo. Following this successful campaign, MAGIC is continuing collecting data on Perseus.
@article{arxiv.1308.0492,
title = {MAGIC Gamma-ray Observations of the Perseus Galaxy Cluster},
author = {Fabio Zandanel and Pierre Colin and Saverio Lombardi and Michele Doro and Dorit Eisenacher and Dorothee Hildebrand and Francisco Prada and Christoph Pfrommer and Anders Pinzke},
journal= {arXiv preprint arXiv:1308.0492},
year = {2019}
}
Comments
4 pages, 2 figures, Proc. of 33rd ICRC, Rio de Janeiro, Brazil