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F. Jaron:
"A Precessing Jet Scenario for the Multi-Wavelength Long-Term Modulation of LS I +61°303";
Universe, 7 (2021), 7; 1 - 16.

The high-mass X-ray binary LS I +61°303 is detected across the electromagnetic spectrum from radio until the very high energy γ-ray regime. The emission is not only highly variable on many time scales, but is also periodic at all observed wavelengths. Periodic modulation was observed on different time-scales, ranging from hours, over months to several years. The subject of this article is a super-orbital, long-term modulation of ∼4.6 years. We review the observation of this periodic modulation at multiple wavelengths and investigate systematic relationships between them. IN particular, radio observations reveal that the long-term modulation is a very stable feature of the source. Observations at other wavelengths result in a phase-shift of the modulation pattern that is a systematic function of energy. The stability of this period favors a scenario in which the long-term modulation is the result of a precessing jet giving rise to periodic changes in the Doppler factor, beating with the orbital modulation of the accretion rate. We explain the phase-shifts across energy bands in a scenario with shorter wavelengths originating closer to the base of the precessing jet. A significant deviation of the TeV emission from this trend possibly requires a different explanation related to magnetic reconnection events.

X-ray binaries, high-energy astrophysical phenomena, stars individual: LS I +61°3

http://dx.doi.org/10.3390/universe7070245

https://publik.tuwien.ac.at/files/publik_299001.pdf