Near-periodical spin period evolution in the binary system LMC X-4

: Molkov S, Lutovinov A, Falanga M, Tsygankov S, Bozzo E

Publisher: OXFORD UNIV PRESS

: 2017

: Monthly Notices of the Royal Astronomical Society

: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

: MON NOT R ASTRON SOC

: 464

: 2

: 2039

: 2045

: 7

: 0035-8711

: 1365-2966

DOI: https://doi.org/10.1093/mnras/stw2429

: https://research.utu.fi/converis/portal/detail/Publication/28601063

In this paper, we investigated the long-term evolution of the pulse period in the high-mass X-ray binary LMC X-4 by taking advantage of more than 43 yr of measurements in the X-ray domain. Our analysis revealed for the first time that the source is displaying near-periodical variations of its spin period on a time-scale of roughly 6.8 yr, making LMC X-4 one of the known binary systems showing remarkable long-term spin torque reversals. We discuss different scenarios to interpret the origin of these torque reversals.

paper3_lmc2.pdf