Speaker
Description
Until today the supernova remnant (SNR) paradigm provides the most plausible hypothesis for the origin of galactic cosmic rays. In contrast to the acceleration process, the way how cosmic rays are released into the interstellar medium is not well understood yet, partially due to the lack of observational signatures. Such a signature could be provided by gamma-rays produced in the interaction of escaping particles with the material surrounding the SNR.
The middle-aged (~7000 years old) $\gamma$-Cygni SNR (G78.2+2.1) situated in the dense Cygnus region may be in the right evolutionary phase to study the leakage of cosmic rays into the ISM. The high-energy observations by VERITAS and Fermi-$\textit{LAT}$ revealed a complex, energy-dependent morphology of the SNR in the GeV-TeV band, different from that observed in X-rays.
We present recent, deeper observations of the $\gamma$-Cygni region with the MAGIC telescopes. Combined with 8 years of Fermi-$\textit{LAT}$ data, we find clear evidences for the release of cosmic rays at northern part of the SNR shell. We further discuss these results in the context of the current understanding of cosmic ray escape scenarios.
