Work

Dynamic Accretion Disk–Corona Connection and Broad Fe K α Variability in Mrk 766 Revealed by Time-resolved High-resolution X-Ray Spectroscopic Analysis

Year: 2026

Type: article

Abstract: We present a multiepoch, primarily X-ray study of the narrow-line Seyfert 1 (NLSy1) galaxy Mrk 766 by combining archival XMM-Newton observations spanning nearly 2 decades together with an XRISM observation obtained during its Performance Verification Phase. We analyzed the absorption and emission features in the soft X-ray spectra from Reflection Grating Spectrometer and EPIC-pn data, revealing a stratified multiphase potentially ionized 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 multicomponent Fe K α emission line as revealed by fits to the XRISM data. A quasi-phenomenological model comprising a torus and a broad disk-line 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 K α complex across 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 the Neil Gehrels Swift Observatory X-Ray Telescope and UVOT further indicates UV emission lagging the X-rays by 5 . 9 − 5.7 + 4.1 hr, 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.

Source: The Astrophysical Journal

DOI: 10.3847/1538-4357/aea83d

Authors: Ayon Mondal, Tathagata Saha, Arijit Sar, Ritaban Chatterjee

Institutions: Presidency University, Presidency University, University of Maryland, Baltimore County, Inter-University Centre for Astronomy and Astrophysics

Language: English

Topic: Astrophysical Phenomena and Observations

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,499