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arXiv · 1601.03260

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

A. D'Aì·G. Cusumano·V. La Parola·A. Segreto·T. Mineo
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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.

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A. D'Aì, G. Cusumano, V. La Parola, A. Segreto, T. Mineo. 2016-01-13. Temporal features of LS I +61$^{\circ}$303 in hard X-rays from the Swift/BAT survey data. https://doi.org/10.1093/mnras%2Fstv2716

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