Oral Presentation

[Remote] Shadows and Flares: A Decade-Long Infrared View of Accreting Supermassive Black Holes

Author(s): Suvendu Rakshit (ARIES, Nainital, India)

Presenter: Suvendu Rakshit (Aryabhatta Research Institute of Observational SciencES (ARIES), India)

Infrared variability provides a unique probe of the accretion flow and circumnuclear dust around supermassive black holes (SMBHs). Using WISE and NEOWISE data spanning over a decade, we examined the infrared variability of nearly five million AGN candidates. Variability was quantified through ΔW1, ΔW2, excess variance, reduced χ², and structure-function slopes across 0.5–10-year baselines. Over 600 AGNs exhibit large-amplitude (ΔW1 > 0.5 mag) variations, including several optically classified Type 2 AGNs showing strong IR variability—possible changing-look or TDE events linked to accretion state transitions. Cross-matching with X-ray and radio data reveals enhanced IR variability in X-ray-detected sources, suggesting a closer connection between accretion dynamics and dust reprocessing. These findings offer new insights into the time-dependent behavior of SMBH accretion and the evolving structure of the torus in active galaxies.