Fermi Study of 5-300 GeV emission from the high-mass pulsar binary PSR B1259-63/LS 2883

Abstract

We report the results from our detailed analysis of the Fermi Large Area Telescope (LAT) data for the pulsar binary PSR B1259-63/LS 2883. During the GeV flares that occurred when the pulsar was in the periastron passages, we have detected a 5--300 GeV component at $\simeq 5\sigma$ in emission from the binary. The detection verifies the presence of the component that has been marginally found in the previous studies of the binary. Furthermore, we have discovered that this component was present even in the quiescent state of the binary, specifically the mean anomaly phase 0.7--0.9. The component can be described by a power law with photon index $\Gamma \sim 1.4$, and the flux in the flares is approximately one order of magnitude higher than that in quiescence. We discuss the origin of this component. It likely arises from the inverse-Compton process: high-energy particles from the shock, due to the interaction between the winds from the pulsar and massive companion, scatter the seed photons from the companion to GeV/TeV energies. Based on this scenario, model fits to the broad-band X-ray--to--TeV spectra of the binary in the flaring and quiescent states are provided.

6 pages, 5 figures, submitted

References in corpus (4)

• Discovery of High-Energy Gamma-Ray Emission from the Binary System PSR B1259-63/LS 2883 Around Periastron with Fermi
• TeV lightcurve of PSR B1259-63/SS2883
• High-energy observations of PSR B1259-63/LS 2883 through the 2014 periastron passage: connecting X-rays to the GeV flare
• Probing the Pulsar Wind in the gamma-ray Binary System PSR B1259-63/SS 2883

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• Superorbital modulation at GeV energies in the gamma-ray binary LS I +61 303
• The likely Fermi detection of the Be X-ray binary GRO J1008-57: hint for gamma-ray production in neutron-star X-ray binaries