Ponente
Descripción
Gamma-ray binaries are among the most extreme accelerators in the Galaxy, capable of producing photons at TeV energies. LS 5039, a well-studied high-mass X-ray binary, is one of the few systems known to emit modulated TeV gamma rays. We report the detection of orbital modulation in gamma rays from LS 5039 up to 100 TeV using over 2800 days of observations with the High-Altitude Water Cherenkov (HAWC) Observatory. The emission extends beyond 200 TeV during inferior conjunction, with no evidence of a spectral cutoff, and shows a significant flux difference between superior and inferior conjunction phases. We also find a hint of modulation above 100 TeV. These observations suggest that particle acceleration occurs deep within the binary system, where absorption from stellar photons is expected. While a leptonic origin would require extremely efficient acceleration of electrons to ~200 TeV under low magnetic fields, a hadronic scenario involving PeV protons interacting with dense stellar wind material or X-ray radiation fields provides a more natural explanation. Our results position LS 5039 as a candidate Galactic PeVatron and motivate future multi-messenger searches, including high-energy neutrinos.
