Resolving the Hot Dust Disk of ESO323-G77

TL;DR

This study uses advanced infrared interferometry to confirm the presence of an equatorial hot dust disk in the AGN ESO323-G77, revealing its size, asymmetry, and consistency with theoretical models and previous reverberation mapping data.

Contribution

First direct interferometric evidence confirming the hot dust disk structure in ESO323-G77 and its alignment with theoretical models and reverberation mapping results.

Findings

Hot dust is equatorially extended and asymmetric.

Dust size matches reverberation mapping measurements.

Data aligns with CAT3D-WIND model predictions.

Abstract

Infrared interferometry has fuelled a paradigm shift in our understanding of the dusty structure in the central parsecs of Active Galactic Nuclei (AGN). The dust is now thought to comprise of a hot ($\sim1000\,$K) equatorial disk, some of which is blown into a cooler ($\sim300\,$K) polar dusty wind by radiation pressure. In this paper, we utilise the new near-IR interferometer GRAVITY on the Very Large Telescope Interferometer (VLTI) to study a Type 1.2 AGN hosted in the nearby Seyfert galaxy ESO323-G77. By modelling the squared visibility and closure phase, we find that the hot dust is equatorially extended, consistent with the idea of a disk, and shows signs of asymmetry in the same direction. Furthermore, the data is fully consistent with the hot dust size determined by K band reverberation mapping as well as the predicted size from a CAT3D-WIND model created in previous work using the SED of ESO323-G77 and observations in the mid-IR from VLTI/MIDI.