Speaker
Description
The intricate structure of the most luminous objects in the universe - Active Galactic Nuclei (AGN) - cannot be spatially resolved with current telescopes. Instead, we can probe the inner regions of AGN indirectly by exploiting their highly variable, multi-wavelength nature through the powerful technique of Reverberation Mapping (RM). Ionizing photons in the vicinity of the central black hole illuminate the surrounding optically thick accretion disc, driving correlated but time-lagged variability across the UV and optical continuum. These time-delays provide indirect measurements of the size and temperature profile of the AGN accretion flow, allowing us to put to the test AGN disc and light-reprocessing models. Here I present results from an RM analysis of the highly variable Seyfert I galaxy NGC 3783, using three years of observations from our intensive broadband RM campaign with the Las Cumbres Observatory. While the accretion flow is generally consistent with a standard, geometrically thin thermal disc model, exceptions arise when analysing the variability on different timescales. We see evidence for contamination from an extended reprocessing component on the outskirts of the disc, which may be biasing disc-size measurements in many current AGN RM studies.