Detection of QPO Soft Lag during Outburst of Swift J1727.8-1613: Estimation of Instrinsic Parameters from Spectral Study

Fuente: arXiv
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Main Authors: Debnath, Dipak, Nath, Sujoy Kumar, Chatterjee, Debjit, Chatterjee, Kaushik, Chang, Hsiang-Kuang
Format: Preprint
Published: 2024
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author Debnath, Dipak
Nath, Sujoy Kumar
Chatterjee, Debjit
Chatterjee, Kaushik
Chang, Hsiang-Kuang
author_facet Debnath, Dipak
Nath, Sujoy Kumar
Chatterjee, Debjit
Chatterjee, Kaushik
Chang, Hsiang-Kuang
contents The recently discovered bright transient black hole candidate Swift J1727.8-1613 is studied in a broad energy range ($0.5-79$ keV) using combined NICER and NuSTAR data on 29 August 2023. A promonient type-C Quasi-Periodic Oscillation (QPO) at $0.89 \pm 0.01$ Hz with its harmonic was observed in NICER data of $0.5-10$ keV. Interestingly, the harmonic becomes weaker in the lower energy bands ($0.5-1$ & $1-3$ keV). We also report the first detection of a soft time-lag of $0.014 \pm 0.001$ s at the QPO frequency between harder ($3-10$ kev) and softer ($0.5-3$ keV) band photons observed with the NICER/XTI instrument. This indicates that the inclination of the accretion disk in the binary system might be high. From the detailed spectral analysis with the relxill reflection model, we found the disk inclination angle of source to be $\sim 85^\circ$. We discuss how the accretion flow configuration inferred from spectral analysis can help us to understand the origin of QPOs and soft lag in this source.
format Preprint
id arxiv_https___arxiv_org_abs_2409_14286
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Detection of QPO Soft Lag during Outburst of Swift J1727.8-1613: Estimation of Instrinsic Parameters from Spectral Study
Debnath, Dipak
Nath, Sujoy Kumar
Chatterjee, Debjit
Chatterjee, Kaushik
Chang, Hsiang-Kuang
High Energy Astrophysical Phenomena
The recently discovered bright transient black hole candidate Swift J1727.8-1613 is studied in a broad energy range ($0.5-79$ keV) using combined NICER and NuSTAR data on 29 August 2023. A promonient type-C Quasi-Periodic Oscillation (QPO) at $0.89 \pm 0.01$ Hz with its harmonic was observed in NICER data of $0.5-10$ keV. Interestingly, the harmonic becomes weaker in the lower energy bands ($0.5-1$ & $1-3$ keV). We also report the first detection of a soft time-lag of $0.014 \pm 0.001$ s at the QPO frequency between harder ($3-10$ kev) and softer ($0.5-3$ keV) band photons observed with the NICER/XTI instrument. This indicates that the inclination of the accretion disk in the binary system might be high. From the detailed spectral analysis with the relxill reflection model, we found the disk inclination angle of source to be $\sim 85^\circ$. We discuss how the accretion flow configuration inferred from spectral analysis can help us to understand the origin of QPOs and soft lag in this source.
title Detection of QPO Soft Lag during Outburst of Swift J1727.8-1613: Estimation of Instrinsic Parameters from Spectral Study
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2409.14286