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

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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Cited by in corpus (6)

• Energy-resolved pulse profiles of accreting pulsars: Diagnostic tools for spectral features
• Timing analysis of EXO 2030+375 during its 2021 giant outburst observed with Insight-HXMT
• Beam pattern evolution of accreting X-ray pulsar 1A 0535+262 during its 2020 giant outburst
• Cyclotron line evolution revealed with pulse-to-pulse analysis in the 2020 outburst of 1A 0535+262
• X-Ray Views of Galactic Accreting Pulsars in High-Mass X-Ray Binaries
• Long-term evolution of Cyclotron Line energy in an eclipsing pulsar 4U 1538-522