Temporal features of LS I +61${}^{\circ }$303 in hard X-rays from the Swift/BAT survey data

Abstract

We study the long-term spectral and timing behaviour of LS I +61${}^{\circ }$303 in hard X-rays (15--150 keV) using $\sim$10 years of survey data from the $Swift$ Burst Alert Telescope (BAT) monitor. We focus on the detection of long periodicities known to be present in this source in multiple wavelengths. We clearly detect three periods: the shorter one at 26.48 days is compatible with the orbital period of the system; the second, longer, periodicity at 26.93 days, is detected for the first time in X-rays and its value is consistent with an analogous temporal feature recently detected in the radio and in the gamma-ray waveband, and we associate it with a modulation caused by a precessing jet in this system. Finally, we find also evidence of the long-term periodicity at $\sim$1667 d, that results compatible with a beat frequency of the two close, and shorter, periodicities. We discuss our results in the context of the multi-band behaviour of the physical processes of this source.

5 pages, 8 figures. Published in MNRAS

References in corpus (6)

• VLBA images of the precessing jet of LSI+61303
• Long-term periodicity in LSI+61303 as beat frequency between orbital and precessional rate
• Intrinsic physical properties and Doppler boosting effects in LSI+61303
• Spectral analysis in orbital/superorbital phase space and hints of superorbital variability in the hard X-rays of LS I +61 303
• Discovery of a periodical apoastron GeV peak in LS I +61°303
• Long-term OVRO monitoring of LSI+61303: confirmation of the two close periodicities

Cited by in corpus (6)

• Evidence for periodic accretion-ejection in LSI+61303
• Understanding the periodicities in radio and GeV emission from LS I+61303
• Owens Valley Radio Observatory monitoring of LS I +61°303 completes three cycles of the super-orbital modulation
• A precessing stellar disk model for superorbital modulations of the gamma-ray binary LS I+61${}^{\circ }$ 303
• Achromatic rapid flares in hard X-rays in the $\gamma$-ray binary LS I +61-303
• Rapid X-ray variability of the gamma-ray binary LS I+61 303