Multi-GeV Fermi-LAT Detection of PSR B1259-63

Fuente: arXiv
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Main Authors: Malyshev, D., Chernyakova, M., Gallagher, A. Finn, Kuzin, A., Matchett, N., Santangelo, A., Shebalkova, Iu., van Soelen, B.
Format: Preprint
Published: 2025
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author Malyshev, D.
Chernyakova, M.
Gallagher, A. Finn
Kuzin, A.
Matchett, N.
Santangelo, A.
Shebalkova, Iu.
van Soelen, B.
author_facet Malyshev, D.
Chernyakova, M.
Gallagher, A. Finn
Kuzin, A.
Matchett, N.
Santangelo, A.
Shebalkova, Iu.
van Soelen, B.
contents 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 $Γ= 1.9 \pm 0.1$ 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.
format Preprint
id arxiv_https___arxiv_org_abs_2509_10037
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multi-GeV Fermi-LAT Detection of PSR B1259-63
Malyshev, D.
Chernyakova, M.
Gallagher, A. Finn
Kuzin, A.
Matchett, N.
Santangelo, A.
Shebalkova, Iu.
van Soelen, B.
High Energy Astrophysical Phenomena
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 $Γ= 1.9 \pm 0.1$ 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.
title Multi-GeV Fermi-LAT Detection of PSR B1259-63
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2509.10037