Gamma-Ray Activity from the Binary System PSR B1259-63/SS 2283Near its 2014 Periastron

The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope observed brightening of the binary system PSR B1259-63/SS 2883 in the GeV energy range during the period following the periastron of 2014 May 4. Observed variability is consistent with repetition of the GeV light curve observed at the previous 2010-2011 periastron (binary period 3.4 yr). In the 2014 cycle the Fermi spacecraft was operated in pointed mode for part of the time after periastron to enhance exposure in the LAT. The onset of detectable gamma-ray emission occurred around 2014 June 6, which was 33 days after periastron. We summarize gamma-ray behavior of the source through this cycle and also discuss the broader multi-wavelength context, comparing with the previous cycle. A discussion of the full radio-to-TeV picture of the preceding cycle is available in Chernyakova et al.(2014, MNRAS 439,432). Fermi LAT analysis is supported by NASA.