Multi-wavelength observations of the binary system PSR B1259−63/LS 2883 around the 2014 periastron passage

Abstract

We report on the results of the extensive multi-wavelength campaign from optical to GeV -rays of the 2014 periastron passage of PSR B1259-63, which is a unique high-mass -ray emitting binary system with a young pulsar companion. Observations demonstrate the stable nature of the post-periastron GeV flare and prove the coincidence of the flare with the start of rapid decay of the H equivalent width, usually interpreted as a disruption of the Be stellar disc. Intensive X-ray observations reveal changes in the X-ray spectral behaviour happening at the moment of the GeV flare. We demonstrate that these changes can be naturally explained as a result of synchrotron cooling of monoenergetic relativistic electrons injected into the system during the GeV flare.