Simultaneous long-term monitoring of LS I+61 degrees 303 by OVRO and Fermi-LAT

: Jaron F, Massi M, Kiehlmann S, Hovatta T

Publisher: OXFORD UNIV PRESS

: 2018

: Monthly Notices of the Royal Astronomical Society

: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

: MON NOT R ASTRON SOC

: 478

: 1

: 440

: 447

: 8

: 0035-8711

: 1365-2966

DOI: https://doi.org/10.1093/mnras/sty1037

: https://academic.oup.com/mnras/article/478/1/440/4985847

: https://arxiv.org/abs/1804.07692

Previous long-term monitorings of the gamma-ray-loud X-ray binary LS I +61 degrees 303 have revealed the presence of a long-term modulation of similar to 4.5 yr. After 9 yr of simultaneous monitoring of LS I +61 degrees 303 by the Owens Valley Radio Observatory and the Fermi-LAT, two cycles of the long-term period are now available. Here we perform timing analysis on the radio and the gamma-ray light curves. We confirm the presence of previously detected periodicities at both radio and GeV gamma-ray wavelengths. Moreover, we discover an offset of the long-term modulation between radio and gamma-ray data which could imply different locations of the radio (15 GHz) and GeV emission along the precessing jet.