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arXiv · 2208.13340

Timing properties of the X-ray accreting pulsar 1A 0535+262 studied with Insight-HXMT

P. J. Wang·L. D. Kong·S. Zhang·V. Doroshenko·A. Santangelo·L. Ji·E. S. Yorgancioglu·Y. P. Chen·S. N. Zhang·J. L. Qu·M. Y. Ge·J. Li·Z. Chang·L. Tao·J. Q. Peng·Q. C. Shui
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Abstract

We report results on the timing analysis of the 2020 giant outburst of 1A 0535+262, using broadband data from Insight-HXMT. The analysis of the pulse profile evolution from the sub-critical luminosity to super-critical luminosity regime is presented for the first time. We found that the observed pulse profile exhibits a complex dependence on both energy and luminosity.A dip structure at the energy of the cyclotron resonant scattering features (CRSFs) is found for the first time in the pulse fraction-energy relation of 1A 0535+262, when the outburst evolves in a luminosity range from 4.8 $\times 10^{37}$ erg s$^{-1}$ to 1.0 $\times 10^{38}$ erg s$^{-1}$. The observed structure is luminosity dependent and appears around the source critical luminosity ($\sim$ 6.7 $\times 10^{37}$ erg s$^{-1}$).

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P. J. Wang, L. D. Kong, S. Zhang, V. Doroshenko, A. Santangelo, L. Ji, E. S. Yorgancioglu, Y. P. Chen, S. N. Zhang, J. L. Qu, M. Y. Ge, J. Li, Z. Chang, L. Tao, J. Q. Peng, Q. C. Shui. 2022-08-29. Timing properties of the X-ray accreting pulsar 1A 0535+262 studied with Insight-HXMT. https://doi.org/10.3847/1538-4357/ac8230

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