  The binary system PSR B1259-63/LS 2883 is well sampled in radio, X-rays, and
TeV gamma-rays, and shows orbital phase-dependent variability in these
frequencies. The first detection of GeV gamma-rays from the system was made
around the 2010 periastron passage. In this Letter, we present an analysis of
X-ray and gamma-ray data obtained by the Swift/XRT, NuSTAR/FPM, and Fermi/LAT,
through the recent periastron passage which occurred on 2014 May 4. While PSR
B1259-63/LS 2883 was not detected by the LAT before and during this passage, we
show that the GeV flares occurred at a similar orbital phase as in early 2011,
thus establishing the repetitive nature of the post-periastron GeV flares.
Multiple flares each lasting for a few days have been observed and short-term
variability is seen as well. We also found X-ray flux variation contemporaneous
with the GeV flare for the first time. A strong evidence of the keV-to-GeV
connection came from the broadband high-energy spectra, which we interpret as
synchrotron radiation from the shocked pulsar wind.
