QPOs and Orbital elements of X-ray binary 4U 0115+63 during the 2017 outburst observed by Insight-HXMT
Creators: name: Ding, Y. Z.
name: Wang, W.
name: Zhang, P.
name: Bu, Q. C.
name: Cai, C.
name: Cao, X. L.
name: Zhi, C.
name: Chen, L.
name: Chen, T. X.
name: Chen, Y. B.
name: Chen, Y.
name: Chen, Y. P.
name: Cui, W. W.
name: Du, Y. Y.
name: Gao, G. H.
name: Gao, H.
name: Ge, M. Y.
name: Gu, Y. D.
name: Guan, J.
name: Guo, C. C.
name: Han, D. W.
name: Huang, Y.
name: Huo, J.
name: Jia, S. M.
name: Jiang, W. C.
name: Jin, J.
name: Kong, L. D.
name: Li, B.
name: Li, C. K.
name: Li, G.
name: Li, T. P.
name: Li, W.
name: Li, X.
name: Li, X. B.
name: Li, X. F.
name: Li, Z. W.
name: Liang, X. H.
name: Liao, J. Y.
name: Liu, B. S.
name: Liu, C. Z.
name: Liu, H. X.
name: Liu, H. W.
name: Liu, X. J.
name: Lu, F. J.
name: Lu, X. F.
name: L., Q.
name: T., L.
name: Ma, R. C.
name: Ma, X.
name: Meng, B.
name: Nang, Y.
name: Nie, J. Y.
name: Qu, J. L.
name: Ren, X. Q.
name: Sai, N.
name: Song, L. M.
name: Song, X. Y.
name: Sun, L.
name: Tan, Y.
name: Tao, L.
name: Tuo, Y. L.
name: Wang, L. J.
name: Wang, P. J.
name: Wang, W. S.
name: Wang, Y. S.
name: Wen, X. Y.
name: Wu, B. Y.
name: Wu, B. B.
name: Wu, M.
name: Xiao, G. C.
name: Xiao, S.
name: Xiong, S. L.
name: Xu, Y. P.
name: Yang, R. J.
name: Yang, S.
name: Yang, Y. J.
name: Yi, Q. B.
name: Yin, Q. Q.
name: You, Y.
name: Zhang, F.
name: Zhang, H. M.
name: Zhang, J.
name: Zhang, P.
name: Zhang, S.
name: Zhang, S. N.
name: Zhang, W. C.
name: Zhang, W.
name: Zhang, Y. F.
name: Zhang, Y. H.
name: Zhao, H. S.
name: Zhao, X. F.
name: Zheng, S. J.
name: Zheng, Y. G.
name: Zhou, D. K.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: In this paper, we presented a detailed timing analysis of a prominent outburst of 4U 0115+63 detected by \textit{Insight}-HXMT in 2017 August. The spin period of the neutron star was determined to be $3.61398\pm 0.00002$ s at MJD 57978. We measured the period variability and extract the orbital elements of the binary system. The angle of periastron evolved with a rate of $0.048\pm0.003$ $yr^{-1}$. The light curves are folded to sketch the pulse profiles in different energy ranges. A multi-peak structure in 1-10 keV is clearly illustrated. We introduced wavelet analysis into our data analysis procedures to study QPO signals and perform a detailed wavelet analysis in many different energy ranges. Through the wavelet spectra, we report the discovery of a QPO at the frequency $\sim 10$ mHz. In addition, the X-ray light curves showed multiple QPOs in the period of $\sim 16-32 $ s and $\sim 67- 200 $ s. We found that the $\sim100$ s QPO was significant in most of the observations and energies. There exist positive relations between X-ray luminosity and their Q-factors and S-factors, while the QPO periods have no correlation with X-ray luminosity. In wavelet phase maps, we found that the pulse phase of $\sim 67- 200 $ s QPO drifting frequently while the $\sim 16-32 $ s QPO scarcely drifting. The dissipation of oscillations from high energy to low energy was also observed. These features of QPOs in 4U 0115+63 provide new challenge to our understanding of their physical origins.
description: 14 pages, 9 figures, and 6 tables. This work has been submitted to MNRAS after the referee's report