2025/03/12 by Christos Panagiotou, Panagiotou, Christos, I. E. Papadakis +15 · 1 citation
Medicine · Physics and Astronomy · #Advanced MRI Techniques and Applications #Astrophysics of Galaxies (astro-ph.GA) #Atomic and Subatomic Physics Research #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Magnetic confinement fusion research
paper · pdf · doi:10.48550/arxiv.2503.09036
openalex publication_date 2025/03/12 · openalex created_date 2025/10/13 · openalex updated_date 2026/07/28
Over the last years, a number of broadband reverberation mapping campaigns have been conducted to explore the short-term UV and optical variability of nearby AGN. Despite the extensive data collected, the origin of the observed variability is still debated in the literature. Frequency-resolved time lags offer a promising approach to distinguish between different scenarios, as they probe variability on different time scales. In this study, we present the expected frequency-resolved lags resulting from X-ray reprocessing in the accretion disk. The predicted lags are found to feature a general shape that resembles that of observational measurements, while exhibiting strong dependence on various physical parameters. Additionally, we compare our model predictions to observational data for the case of NGC 5548, concluding that the X-ray illumination of the disk can effectively account for the observed frequency-resolved lags and power spectra in a self-consistent way. To date, X-ray disk reprocessing is the only physical model that has successfully reproduced the observed multi-wavelength variability, in both amplitude and time delays, across a range of temporal frequencies.