The high-energy cyclotron line in 2S 1417-624 discovered with Insight-HXMT during the 2018 outburst

Fuente: arXiv
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Main Authors: Liu, Q., Santangelo, A., Kong, L. D., Ducci, L., Ji, L., Wang, W., Serim, M. M., Güngör, C., Tuo, Y. L., Serim, D.
Format: Preprint
Published: 2024
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author Liu, Q.
Santangelo, A.
Kong, L. D.
Ducci, L.
Ji, L.
Wang, W.
Serim, M. M.
Güngör, C.
Tuo, Y. L.
Serim, D.
author_facet Liu, Q.
Santangelo, A.
Kong, L. D.
Ducci, L.
Ji, L.
Wang, W.
Serim, M. M.
Güngör, C.
Tuo, Y. L.
Serim, D.
contents We report a detailed timing and spectral analysis of the X-ray pulsar 2S~1417-624 using the data from Insight-HXMT during the 2018 outburst. The pulse profiles are highly variable with respect to both unabsorbed flux and energy. A double-peaked pulse profile from the low flux evolved to a multi-peaked shape in the high-flux state. The pulse fraction is negatively correlated to the source flux in the range of $\sim$(1--6)$\ \times \ 10^{-9}$ erg cm$^{-2}$ s$^{-1}$, consistent with \textit{Rossi} X-ray Timing Explorer (RXTE) studies during the 2009 giant outburst. The energy-resolved pulse profiles around the peak outburst showed a four-peak shape in the low-energy bands and gradually evolved to triple peaks at higher energies. The continuum spectrum is well described by typical phenomenological models, such as the cut-off power law and the power law with high-energy cut-off models. Notably, we discovered high-energy cyclotron resonant scattering features (CRSFs) for the first time, which are around 100 keV with a statistical significance of $\sim$7$σ$ near the peak luminosity of the outburst. This CRSF line is significantly detected with different continuum models and provides very robust evidence for its presence. Furthermore, pulse-phase-resolved spectroscopy confirmed the presence of the line, whose energy varied from 97 to 107 keV over the pulse phase and appeared to have a maximum value at the narrow peak phase of the profiles.
format Preprint
id arxiv_https___arxiv_org_abs_2410_22859
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The high-energy cyclotron line in 2S 1417-624 discovered with Insight-HXMT during the 2018 outburst
Liu, Q.
Santangelo, A.
Kong, L. D.
Ducci, L.
Ji, L.
Wang, W.
Serim, M. M.
Güngör, C.
Tuo, Y. L.
Serim, D.
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
We report a detailed timing and spectral analysis of the X-ray pulsar 2S~1417-624 using the data from Insight-HXMT during the 2018 outburst. The pulse profiles are highly variable with respect to both unabsorbed flux and energy. A double-peaked pulse profile from the low flux evolved to a multi-peaked shape in the high-flux state. The pulse fraction is negatively correlated to the source flux in the range of $\sim$(1--6)$\ \times \ 10^{-9}$ erg cm$^{-2}$ s$^{-1}$, consistent with \textit{Rossi} X-ray Timing Explorer (RXTE) studies during the 2009 giant outburst. The energy-resolved pulse profiles around the peak outburst showed a four-peak shape in the low-energy bands and gradually evolved to triple peaks at higher energies. The continuum spectrum is well described by typical phenomenological models, such as the cut-off power law and the power law with high-energy cut-off models. Notably, we discovered high-energy cyclotron resonant scattering features (CRSFs) for the first time, which are around 100 keV with a statistical significance of $\sim$7$σ$ near the peak luminosity of the outburst. This CRSF line is significantly detected with different continuum models and provides very robust evidence for its presence. Furthermore, pulse-phase-resolved spectroscopy confirmed the presence of the line, whose energy varied from 97 to 107 keV over the pulse phase and appeared to have a maximum value at the narrow peak phase of the profiles.
title The high-energy cyclotron line in 2S 1417-624 discovered with Insight-HXMT during the 2018 outburst
topic High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2410.22859