Timing analysis of EXO 2030+375 during its 2021 giant outburst observed with<i>Insight</i>-HXMT

Fu, Yang; Song, Liming; Ding, Guoqiang; Ge, M. Y.; Tuo, You-Li; Zhang, S; Zhang, S N; Hou, X.; Qu, J. L.; Zhang, J; Zhang, L.; Bu, Q. C.; Huang, Y.; Ma, Xiang; Xia, Zhou; Yan, W. M.; Yang, Zi-Xu; Lu, X. F.; Li, T M; Xu, Yupeng; Wang, P J; Xiao, Shuo; Liu, H X; Ren, Xiaokang; Du, Yifeng; Zhao, Qifan; Xiao, Y X

doi:10.1093/mnras/stad614

Cited by 9 publications

(7 citation statements)

References 56 publications

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“…It is the only satellite that can measure pulse energies exceeding 100 keV and its wide energy range provides the opportunity to determine L crit using the method that is described above. In previous studies, >130 keV pulsations have been detected from the PULX RX J0209.6-7427 (Hou et al 2022) using Insight-HXMT data, and the method has been verified in two accreting X-ray pulsars EXO 2030+375 (Fu et al 2023) and RX J0440.9+4431 (Li et al 2023), respectively.…”

Section: Introductionmentioning

confidence: 84%

Searching for the Highest Energy of Pulsation and Critical Luminosity of Swift J0243.6+6124 Observed by Insight-HXMT

Zhao,

Hou,

et al. 2024

Res. Astron. Astrophys.

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Owing to the broad energy coverage of Insight-HXMT in the hard X-ray band, we detected the highest energy of pulsation exceeding 200 keV around the 2017-2018 outburst peak of the first Galactic pulsating ultraluminous X-ray source (PULX) Swift J0243.6+6124, which is the highest energy detected from PULXs to date. We also obtained the highest energy of pulsation of every exposure during the outburst in 2017-2018, and found the highest energy is roughly positively correlated with luminosity. Using our newly developed method, we identified the critical luminosity being 4 × 1038 erg s−1 when the main peaks of the low and high energy pulse profiles became aligned, which separates the fan-beam dominated and pencil-beam dominated accretion regimes. Above the critical luminosity, the phase of the main peak shifted gradually from 0.5 to 0.8 until the outburst peak in all energy bands, in agreement with the phase shift found previously at low energies. Our result is consistent with that derived from spectral analysis.

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Section: Introductionmentioning

confidence: 84%

Searching for the Highest Energy of Pulsation and Critical Luminosity of Swift J0243.6+6124 Observed by Insight-HXMT

Zhao,

Hou,

et al. 2024

Res. Astron. Astrophys.

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“…Since the neutrino is a spin-half electrically neutral particle, it can be described by a Majorana field with the antineutrino characterized by the opposed helicity. The unknown nature of the neutrino that could be a Dirac or a Majorana spinor is currently the subject of experimental investigations at CUORE [40], GERDA [41], MAJORANA [42], SNO+ [43], and EXO [44]. The experimental results suggest that the neutrinos have non-zero masses and oscillations.…”

Section: Neutrinos Massmentioning

confidence: 99%

Neutrino Masses in Supersymmetric Models with R-Symmetry

Rodriguez,

Vancea

2023

Particles

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In this article, we give a brief review of the origin of the neutrino mass in some interesting non-linear supersymmetric models with R-symmetry. These models are able to address and solve the most important problems of particle physics and provide mechanisms for neutrino mass generation and their mixing parameters in agreement with the current experimental data. Their prediction could be experimentally tested in the near future by collider experiments.

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“…BeXB pulsar EXO 2030+375 was discovered by EXOSAT during a giant X-ray outburst (Type II outburst; Parmar et al 1989). In this system, the pulsar with a spin period of 42 s (Fu et al 2023) orbits a B0 Ve star (Janot-Pacheco et al 1988) along with an orbital modulation of 46 days (Wilson et al 2005). The system was located at a distance of 7.1 kpc measured by optical and infrared observations (Motch & Janot-Pacheco 1987;Coe et al 1988), but the latest measured distance is 3.6 1.3 0.9 -+ kpc by Gaia (Arnason et al 2021).…”

Section: Introductionmentioning

confidence: 97%

“…In 2006 June, EXO 2030+375 was observed to experience the second giant outburst since its discovery, with the source flux peaking up to ∼750 mCrab from the INTEGRAL observatory (Klochkov et al 2008). In 2021, the third giant outburst with peak flux up to ∼550 mCrab was monitored with the X-ray instruments on board the MAXI/GSC, NICER, Fermi/GBM, Swift/BAT, NuSTAR, Insight-HXMT, and IXPE observatories (Nakajima et al 2021;Thalhammer et al 2021;Tamang et al 2022;Fu et al 2023;Malacaria et al 2023). Fu et al (2023) showed the pulse profile evolution during the outburst based on Insight-HXMT data.…”

Section: Introductionmentioning

confidence: 99%

“…In 2021, the third giant outburst with peak flux up to ∼550 mCrab was monitored with the X-ray instruments on board the MAXI/GSC, NICER, Fermi/GBM, Swift/BAT, NuSTAR, Insight-HXMT, and IXPE observatories (Nakajima et al 2021;Thalhammer et al 2021;Tamang et al 2022;Fu et al 2023;Malacaria et al 2023). Fu et al (2023) showed the pulse profile evolution during the outburst based on Insight-HXMT data. IXPE observations suggest a low polarization degree, and the magnetic axis of EXO 2030+375 swings close to the observer's line of sight (Malacaria et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

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Evidence for a Cyclotron Absorption Line and Spectral Transition in EXO 2030+375 during the 2021 Giant Outburst

Yang,

Wang,

Epili

2024

ApJ

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Based on Insight-HXMT observations of EXO 2030+375 during its 2021 giant outburst, we report the analysis of pulse variations and the broadband X-ray spectrum, and find the presence of a potential cyclotron resonant scattering feature (CRSF) with the fundamental line at ∼47 keV from both average spectra and phase-resolved spectroscopy. During the outburst, the source reached an X-ray luminosity of ∼1038 erg s−1 from 2 to 105 keV at a distance of 7.1 kpc. The X-ray pulsar at the spin period of 41.27 ± 0.61 s exhibits complex timing and spectral variations with both energy and luminosity during the outburst. The shapes of the pulse profiles show the single main peak above ∼20 keV, while appearing to exhibit multipeak patterns in low-energy bands, and the transition of the 10–20 keV pulse profiles from multipeak to single peak is observed at ∼0.8 × 1038 erg s−1, which suggests the evolution from the subcritical luminosity (pencil-beam dominated) to the supercritical luminosity (fan-beam dominated) regime. A dip structure before the energy of the CRSFs is found in the pulse fraction–energy relation of EXO 2030+375 near the peak luminosity. A detailed analysis of spectral parameters showed that the power-law photon index exhibits three distinct trends as luminosity increases, and these spectral changes also signify a spectral transition from subcritical to supercritical regimes. The critical luminosity infers a magnetic field of ∼(4.8−6.0) × 1012 G, which supports the presence of the cyclotron line at ∼47 keV. A Comptonization model applied for the broad X-ray spectra during the outburst also suggests the surface magnetic field ranging from ∼(5−9) × 1012 G.

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Timing analysis of EXO 2030+375 during its 2021 giant outburst observed withInsight-HXMT

Cited by 9 publications

References 56 publications

Searching for the Highest Energy of Pulsation and Critical Luminosity of Swift J0243.6+6124 Observed by Insight-HXMT

Searching for the Highest Energy of Pulsation and Critical Luminosity of Swift J0243.6+6124 Observed by Insight-HXMT

Neutrino Masses in Supersymmetric Models with R-Symmetry

Evidence for a Cyclotron Absorption Line and Spectral Transition in EXO 2030+375 during the 2021 Giant Outburst

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