Dynamic Accretion Disk-Corona Connection and Broad Fe Kα Variability in Mrk 766 Revealed by Time-Resolved High Resolution X-Ray Spectroscopic Analysis
Abstract
We present a multi-epoch, primarily X-ray study of the narrow-line Seyfert 1 (NLSy1) galaxy Mrk~766 by combining archival \textit{XMM-Newton} observations spanning nearly two decades together with a \textit{XRISM} observation obtained during its Performance Verification Phase. We analyzed the absorption and emission features in the soft X-ray spectra from RGS and EPIC-pn data, revealing a stratified multi-phase potentially ionised absorber with a column density varying at a timescale of ∼1 day. The covering fraction shows positive correlation with the continuum flux, however with significant intrinsic scatter, between the epochs. Mrk~766 exhibits a multi-component Fe\,Kα emission line as revealed by fits to the \textit{XRISM} data. A quasi-phenomenological model comprising a torus and a broad \textit{diskline} component distinguishes the two components and constrains the inner radius of the potential broad line emitting disk substructure between Rin=40−60 rg. Analysis of multiple epochs of the Fe Kα complex across \textit{XMM-Newton} observations reveals that the broad component tracks the continuum flux closely and effectively reflects the trend with respect to the continuum. The narrow component is consistent with a distant emitter, potentially the torus. Quasi-simultaneous monitoring with \textit{Swift}-XRT and UVOT further indicates UV emission lagging the X-rays by 5.9+4.1−5.7 hours, consistent with disk reprocessing of coronal X-ray fluctuations, and corresponds to a light travel distance of up to 103 rg. Overall, our analysis maps the extent of the dynamically evolving absorber, the iron line emitter, and the accretion disk in this highly accreting NLSy1 system.
Versions
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BibTeX
@misc{mondal2026dynamic,
title = {{Dynamic Accretion Disk-Corona Connection and Broad Fe K$α$ Variability in Mrk 766 Revealed by Time-Resolved High Resolution X-Ray Spectroscopic Analysis}},
author = {Ayon Mondal and Tathagata Saha and Arijit Sar and Ritaban Chatterjee},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.16151},
eprint = {2609.16151},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.16151},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Dynamic Accretion Disk-Corona Connection and Broad Fe Kα Variability in Mrk 766 Revealed by Time-Resolved High Resolution X-Ray Spectroscopic Analysis
AU - Ayon Mondal
AU - Tathagata Saha
AU - Arijit Sar
AU - Ritaban Chatterjee
PY - 2026
DA - 2026/09/14
PB - arXiv
DO - 10.48550/arxiv.2609.16151
UR - https://arxiv.org/abs/2609.16151
AB - We present a multi-epoch, primarily X-ray study of the narrow-line Seyfert 1 (NLSy1) galaxy Mrk~766 by combining archival \textit{XMM-Newton} observations spanning nearly two decades together with a \textit{XRISM} observation obtained during its Performance Verification Phase. We analyzed the absorption and emission features in the soft X-ray spectra from RGS and EPIC-pn data, revealing a stratified multi-phase potentially ionised absorber with a column density varying at a timescale of ∼1 day. The covering fraction shows positive correlation with the continuum flux, however with significant intrinsic scatter, between the epochs. Mrk~766 exhibits a multi-component Fe\,Kα emission line as revealed by fits to the \textit{XRISM} data. A quasi-phenomenological model comprising a torus and a broad \textit{diskline} component distinguishes the two components and constrains the inner radius of the potential broad line emitting disk substructure between R_in=40−60 r_g. Analysis of multiple epochs of the Fe Kα complex across \textit{XMM-Newton} observations reveals that the broad component tracks the continuum flux closely and effectively reflects the trend with respect to the continuum. The narrow component is consistent with a distant emitter, potentially the torus. Quasi-simultaneous monitoring with \textit{Swift}-XRT and UVOT further indicates UV emission lagging the X-rays by 5.9^+4.1_−5.7 hours, consistent with disk reprocessing of coronal X-ray fluctuations, and corresponds to a light travel distance of up to 10^3 r_g. Overall, our analysis maps the extent of the dynamically evolving absorber, the iron line emitter, and the accretion disk in this highly accreting NLSy1 system.
ER -