2012/05/31 by Benoît Cerutti, Benoit Cerutti, G. Werner +4 · 129 citations
Physics and Astronomy · #Active galactic nucleus #Astrophysical jet #Astrophysics #Astrophysics and Cosmic Phenomena #Blazar #Computational physics #Crab Nebula #Dark Matter and Cosmic Phenomena #Electron #Galaxy #Gamma ray #Ionosphere and magnetosphere dynamics #Kinetic energy #Magnetic reconnection #Nuclear physics #Optics #Photon #Physics #Plasma #Radiation #Relativistic beaming #Relativistic particle #Synchrotron radiation #astro-ph.HE #physics.plasm-ph
paper · pdf · doi:10.1088/2041-8205/754/2/l33
published in The Astrophysical Journal Letters 754(2), L33 (IOP Publishing) · 14 pages, 5 figures, Accepted for publication in The Astrophysical Journal Letters
arxiv created 2012/07/03 · openalex publication_date 2012/07/16 · arxiv updated 2015/06/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report on the first study of the angular distribution of energetic particles and radiation generated in relativistic collisionless electron–positron pair plasma reconnection using two-dimensional particle-in-cell simulations. We discover a strong anisotropy of the particles accelerated by reconnection and the associated strong beaming of their radiation. The focusing of particles and radiation increases with their energy; in this sense, this "kinetic beaming" effect differs fundamentally from the relativistic Doppler beaming usually invoked in high-energy astrophysics, in which all photons are focused and boosted achromatically. We also present, for the first time, the modeling of the synchrotron emission as seen by an external observer during the reconnection process. The expected light curves comprise several bright symmetric sub-flares emitted by the energetic beam of particles sweeping across the line of sight intermittently, and exhibit super-fast time variability as short as about one-tenth of the system light-crossing time. The concentration of the energetic particles into compact regions inside magnetic islands and particle anisotropy explain the rapid variability. This radiative signature of reconnection can account for the brightness and variability of the gamma-ray flares in the Crab Nebula and in blazars.