Fermi-LAT Observation of PSR B1259-63 during Its 2021 Periastron Passage

Abstract

PSR B1259-63 is a $\gamma$-ray binary system, where the compact object is a pulsar. The system has an orbital period of 1236.7 days and shows peculiar $\gamma$-ray flares (in 100\,MeV--300\,GeV) after its periastron time. We analyzed the \textit{Fermi}-LAT observation of PSR B1259-63 during its latest periastron passage, as well as its previous three periastrons. The bright GeV flares started about 60 days after the periastron epoch in 2021. This delay is larger than that around the 2017 periastron and much larger than earlier periastrons. The delay of the GeV flux peak time in each periastron passage is apparent in our results. We discussed the possible origin of this delay and made a prediction of the GeV flux peak time in next periastron passage, based on observation of the previous delays.

accepted for publication in Universe

References in corpus (5)

• Detection of 16 Gamma-Ray Pulsars Through Blind Frequency Searches Using the Fermi LAT
• Discovery of High-Energy Gamma-Ray Emission from the Binary System PSR B1259-63/LS 2883 Around Periastron with Fermi
• Sizing up the population of gamma-ray binaries
• New insight into the origin of the GeV flare in the binary system PSR B1259-63 from the 2017 periastron passage
• H.E.S.S. and Fermi-LAT observations of PSR B1259-63/LS 2883 during its 2014 and 2017 periastron passages

Cited by in corpus (4)

• An update on Fermi-LAT transients in the Galactic plane, including strong activity of Cygnus X-3 in mid-2020
• Possible TeV $\gamma$-ray binary origin of HESS J1828-099
• An unidentified Fermi source emitting radio bursts in the Galactic bulge
• NuSTAR Analysis of the 2024 Periastron Passage of TeV Binary PSR B1259-63