סמינר באסטרונומיה ובאסטרופיזיקה: Probing Changing-Look Active Galactic Nuclei with Long-Term Multiwavelength Monitoring and Reverberation Mapping

Zoom: https://tau-ac-il.zoom.us/j/87185167411?pwd=FpTUyIgXaOturzOFSetA6pPVYQilen.1

Abstract:

Changing-look active galactic nuclei (CL AGNs) undergo dramatic transitions in their spectral type and line properties on timescales ranging from days to years. In 2016, we initiated a long-term multiwavelength (IR–X-ray) monitoring program targeting a sample of CL AGNs using both ground- and space-based facilities, including ShAO, SAI, MASTER, Swift, WIRO, SAAO, and WISE. The primary goal of this program is to investigate the recurrence of changing-look events and to constrain the physical mechanisms driving their rapid, large-amplitude variability.

Our results include reverberation mapping based on multiwavelength continuum variations, as well as on the variability of broad permitted and forbidden coronal lines. We report the first detections of coronal-line variability in NGC 4151, NGC 1566, and NGC 3516. In addition, we present the discovery of new changing-look events in several AGNs.

These results provide new constraints on the origin of changing-look phenomena and offer important insights into the structure and variability of active galactic nuclei.

מארגן הסמינר: ד"ר יהונתן שטרן