Timing and spectral variability of the high-mass X-ray pulsar GX 301-2 over orbital phases observed by Insight-HXMT
Ding, Y. Z.; Wang, W.; Epili, P. R.; Liu, Q.; Ge, M. Y.; Lu, F. J.; Qu, J. L.; Song, L. M.; Zhang, S.; Zhang, S. N.
刊名Monthly Notices of the Royal Astronomical Society
2021
卷号506页码:2712
关键词stars: neutron pulsars: individual: GX 301-2 X-rays: stars
ISSN号0035-8711
DOI10.1093/mnras/stab1862
文献子类Journal Article
英文摘要

We report the orbital X-ray variability of the high-mass X-ray binary (HMXB) GX 301-2. GX 301-2 underwent a spin-up process in 2018-2020 with the period evolving from ~685-670 s. The energy-resolved pulse profiles of the pulsar at 1-60 keV varied from single-peaked and sinusoidal shapes to multipeaked ones across different orbital phases. Pulse fractions evolving over the orbit had negative correlations with the X-ray flux. The broad-band X-ray energy spectrum of the pulsar can be described with a partially covered negative-positive cut-off power-law continuum model. Near the periastron passage of the pulsar we found strong variation in the additional column density ($N_{\mathrm{H}_{2}}$), which correlated with variation of the flux. Curves of growth for both Fe K`and Fe Klines were plotted to investigate the distribution of matter around the neutron star. We also found evidence for two cyclotron absorption lines in the phase-averaged spectra in GX 301-2, with one line of 30-42 keV and the other line varying over 48-56 keV. The centroid energies of both lines show a similar relationship with X-ray luminosity: positive correlation in the lower luminosity range, and a negative relation above a critical luminosity of $10^{37}\, \rm erg\, s^{-1}$. We estimate the surface magnetic field of the neutron star in GX 301-2 to be ~(0.5-2) × 1013 G. The two cyclotron line energies have a nearly fixed ratio of ~1.63 while having a low strength ratio (~0.05), suggesting that these two features may actually be one line.

内容类型期刊论文
源URL[http://ir.ihep.ac.cn/handle/311005/289800]  
专题高能物理研究所_粒子天体物理中心
硬X射线调制望远镜卫星
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Ding, Y. Z.,Wang, W.,Epili, P. R.,et al. Timing and spectral variability of the high-mass X-ray pulsar GX 301-2 over orbital phases observed by Insight-HXMT[J]. Monthly Notices of the Royal Astronomical Society,2021,506:2712.
APA Ding, Y. Z..,Wang, W..,Epili, P. R..,Liu, Q..,Ge, M. Y..,...&Zhang, S. N..(2021).Timing and spectral variability of the high-mass X-ray pulsar GX 301-2 over orbital phases observed by Insight-HXMT.Monthly Notices of the Royal Astronomical Society,506,2712.
MLA Ding, Y. Z.,et al."Timing and spectral variability of the high-mass X-ray pulsar GX 301-2 over orbital phases observed by Insight-HXMT".Monthly Notices of the Royal Astronomical Society 506(2021):2712.
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