2025/09/12 by D. Malyshev, Malyshev, D., M. Chernyakova +13
Physics and Astronomy · #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Nuclear Physics and Applications #Particle Detector Development and Performance #Radiation Detection and Scintillator Technologies
paper · pdf · doi:10.48550/arxiv.2509.10037
openalex publication_date 2025/09/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
PSR B1259-63/LS 2883 is a classical gamma-ray binary detected from radio to TeV energies near periastron. Using over 17 years of Fermi-LAT observations, we report the first significant detection (8σ in likelihood analysis) of the system in the 10-100 GeV energy range, over orbital phases from -400 to +100 days relative to periastron. The observed spectrum is well described by a power law with photon index Γ= 1.9 ± 0.1 and shows a flux level consistent with that measured at TeV energies by H.E.S.S. The smooth connection between the Fermi-LAT and TeV spectra suggests that the detected multi-GeV emission traces the rising tail of the inverse-Compton component extending into the TeV regime. The presence of detectable emission hundreds of days before periastron indicates high-energy activity over a larger orbital phase range than previously established, enabling new constraints on particle-acceleration and radiative processes in the system.