On the origin of accretion flow photon index–quasi-periodic oscillation frequency (Γ–vQPO) relation

Abstract MAXI J1535-571 outburst was dramatic and the accretion flow exhibits spectra-temporal characteristics related to one another. In this study, MAXI J1535-571 data observed by SWIFT/BAT (Swift/Burst Alert Telescope) and MAXI/GSC (Monitor of All-sky X-ray Image/Gas slit camera) was analyzed. Th...

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Main Authors: Ambrose C. Eze, Romanus N. C. Eze, Augustine E. Chukwude, Fidelis Okey Madu
Format: Article
Language:English
Published: Nature Portfolio 2025-04-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-024-83345-z
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author Ambrose C. Eze
Romanus N. C. Eze
Augustine E. Chukwude
Fidelis Okey Madu
author_facet Ambrose C. Eze
Romanus N. C. Eze
Augustine E. Chukwude
Fidelis Okey Madu
author_sort Ambrose C. Eze
collection DOAJ
description Abstract MAXI J1535-571 outburst was dramatic and the accretion flow exhibits spectra-temporal characteristics related to one another. In this study, MAXI J1535-571 data observed by SWIFT/BAT (Swift/Burst Alert Telescope) and MAXI/GSC (Monitor of All-sky X-ray Image/Gas slit camera) was analyzed. The physical and phenomenological models that explain the components of the accretion flow were adopted in fitting/modelling the data in XSPEC v12.10.1f. The accretion flow characteristics and photon index–quasi-periodic oscillation frequency (Γ–vQPO) relation and their correlations were determined. The resonance condition in the range of (0.507–1.248) ± 0.080 indicates that the components of the accretion flow timescales are comparable. The QPO frequency of 0.840–4.961 Hz was obtained. This affirms the TCAF model prediction of the presence of QPO in the accretion flow during the hard spectral states. The components of accretion flow rates are anti-correlated. This suggests that components of the accretion flow interact at varying distances and cause the distribution of energy spectral indices in the post-shock region/Compton cloud. The photon index–QPO frequency is tightly correlated with a coefficient of 0.973. Hence, the variations/fluctuation of accretion flow/rates seems to be the underlying physical processes/mechanisms responsible for the origin of Γ–vQPO relation in the hard-intermediate spectral state.
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spelling doaj-art-2a6ad71fcbca482293d3c83ae59f46392025-08-20T02:25:40ZengNature PortfolioScientific Reports2045-23222025-04-0115111110.1038/s41598-024-83345-zOn the origin of accretion flow photon index–quasi-periodic oscillation frequency (Γ–vQPO) relationAmbrose C. Eze0Romanus N. C. Eze1Augustine E. Chukwude2Fidelis Okey Madu3Department of Physics and Geosciences, Faculty of Natural Sciences and Environmental Studies, Godfrey Okoye UniversityDepartment of Physics and Astronomy, Faculty of Physical Sciences, University of NigeriaDepartment of Physics and Astronomy, Faculty of Physical Sciences, University of NigeriaDepartment of Physics and Geosciences, Faculty of Natural Sciences and Environmental Studies, Godfrey Okoye UniversityAbstract MAXI J1535-571 outburst was dramatic and the accretion flow exhibits spectra-temporal characteristics related to one another. In this study, MAXI J1535-571 data observed by SWIFT/BAT (Swift/Burst Alert Telescope) and MAXI/GSC (Monitor of All-sky X-ray Image/Gas slit camera) was analyzed. The physical and phenomenological models that explain the components of the accretion flow were adopted in fitting/modelling the data in XSPEC v12.10.1f. The accretion flow characteristics and photon index–quasi-periodic oscillation frequency (Γ–vQPO) relation and their correlations were determined. The resonance condition in the range of (0.507–1.248) ± 0.080 indicates that the components of the accretion flow timescales are comparable. The QPO frequency of 0.840–4.961 Hz was obtained. This affirms the TCAF model prediction of the presence of QPO in the accretion flow during the hard spectral states. The components of accretion flow rates are anti-correlated. This suggests that components of the accretion flow interact at varying distances and cause the distribution of energy spectral indices in the post-shock region/Compton cloud. The photon index–QPO frequency is tightly correlated with a coefficient of 0.973. Hence, the variations/fluctuation of accretion flow/rates seems to be the underlying physical processes/mechanisms responsible for the origin of Γ–vQPO relation in the hard-intermediate spectral state.https://doi.org/10.1038/s41598-024-83345-zMAXI J1535-571Hard-intermediate stateAccretion flow characteristicsMass accretion ratesResonance conditionPhoton index–QPO frequency relation
spellingShingle Ambrose C. Eze
Romanus N. C. Eze
Augustine E. Chukwude
Fidelis Okey Madu
On the origin of accretion flow photon index–quasi-periodic oscillation frequency (Γ–vQPO) relation
Scientific Reports
MAXI J1535-571
Hard-intermediate state
Accretion flow characteristics
Mass accretion rates
Resonance condition
Photon index–QPO frequency relation
title On the origin of accretion flow photon index–quasi-periodic oscillation frequency (Γ–vQPO) relation
title_full On the origin of accretion flow photon index–quasi-periodic oscillation frequency (Γ–vQPO) relation
title_fullStr On the origin of accretion flow photon index–quasi-periodic oscillation frequency (Γ–vQPO) relation
title_full_unstemmed On the origin of accretion flow photon index–quasi-periodic oscillation frequency (Γ–vQPO) relation
title_short On the origin of accretion flow photon index–quasi-periodic oscillation frequency (Γ–vQPO) relation
title_sort on the origin of accretion flow photon index quasi periodic oscillation frequency γ vqpo relation
topic MAXI J1535-571
Hard-intermediate state
Accretion flow characteristics
Mass accretion rates
Resonance condition
Photon index–QPO frequency relation
url https://doi.org/10.1038/s41598-024-83345-z
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