2024/06/04 by Zhang, Pengfei · 1 citation
#FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE)
paper · doi:10.48550/arxiv.2406.02042
LS I + 61^∘303 is a high-mass X-ray binary system comprising a massive Be star and a rapidly rotating neutron star. Its spectral energy distribution across multi-wavelengths categorizes it as a γ-ray binary system. In our analysis of LS I + 61^∘303 using Fermi-LAT observations, we not only confirmed the three previously discussed periodicities of orbital, superorbital, and orbital-superorbital beat periods observed in multi-wavelength observations, but also identified an additional periodic signal. This newly discovered signal exhibits a period of ∼26.3 day at a ∼7σ confidence level. Moreover, the power spectrum peak of the new signal gradually decreases as the energy increases across the energy ranges of 0.1-0.3, 0.3-1.0, and 1.0-500.0 GeV. Interestingly, a potential signal with a similar period was found in data obtained from the Owens Valley Radio Observatory 40 m telescope. We suggest that the newly discovered periodic signal may originate from a coupling between the orbital period and the retrograde stellar precession period.