@article{BohdanNiemiecPohletal.2019,
  author    = {Bohdan, Artem and Niemiec, Jacek and Pohl, Martin and Matsumoto, Yosuke and Amano, Takanobu and Hoshino, Masahiro},
  title     = {Kinetic Simulations of Nonrelativistic Perpendicular Shocks of Young Supernova Remnants. II. Influence of Shock-surfing Acceleration on Downstream Electron Spectra},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {885},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  number    = {1},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.3847/1538-4357/ab43cf},
  pages     = {9},
  year      = {2019},
  abstract  = {We explore electron preacceleration at high-Mach-number nonrelativistic perpendicular shocks at, e.g., young supernova remnants, which are a prerequisite of further acceleration to very high energies via diffusive shock acceleration. Using fully kinetic particle-in-cell simulations of shocks and electron dynamics in them, we investigate the influence of shock-surfing acceleration (SSA) at the shock foot on the nonthermal population of electrons downstream of the shock. The SSA is followed by further energization at the shock ramp where the Weibel instability spawns a type of second-order Fermi acceleration. The combination of these two processes leads to the formation of a nonthermal electron population, but the importance of SSA becomes smaller for larger ion-to-electron mass ratios in the simulation. We discuss the resulting electron spectra and the relevance of our results to the physics of systems with real ion-to-electron mass ratios and fully three-dimensional behavior.},
  language  = {en}
}
@article{HaeffnerStegmannJungRichardt2015,
  author    = {Haeffner, Stephanie and Stegmann, Christian and Jung-Richardt, Ira},
  title     = {Systematic search for molecular clouds near supernova remnants as sources of very-high-energy gamma-ray emission},
  series = {Astroparticle physics},
  volume    = {71},
  journal   = {Astroparticle physics},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0927-6505},
  doi       = {10.1016/j.astropartphys.2015.05.004},
  pages     = {36 -- 44},
  year      = {2015},
  abstract  = {Supernova remnants accelerate particles up to energies of at least 100 TeV as established by observations in very-high-energy gamma-ray astronomy. Molecular clouds in their vicinity provide an increased amount of target material for proton-proton interaction and subsequent neutral pion decay into gamma-rays of accelerated hadrons escaping the remnant. Therefore, these molecular clouds are potential gamma-ray sources. The gamma-ray emission from these clouds provides a unique environment to derive information on the propagation of very-high-nergy particles through the interstellar medium as well as on the acceleration of hadrons in supernova remnants. Current Imaging Atmospheric Cherenkov Telescope systems are suitable to explore a large parameter space of the propagation properties depending on the age of the supernova remnant and the distance between the remnant and the nearby molecular cloud. In this paper we present our strategy and results of a systematic search for gamma-ray emitting molecular clouds near supernova remnants which are potentially detectable with current experiments in the TeV energy range and explore the prospects of future experiments.},
  language  = {en}
}