For the past 30 years, a toroidal structure in the equatorial plane around active galactic nuclei (AGN), the so-called dusty and molecular torus, has been considered a cornerstone of unified schemes of quasars and Seyfert galaxies. However, this picture has recently been challenged by a number of observations across the electromagnetic spectrum. In the infrared, there was the discovery of polar elongated dust structures, rather than doughnut shaped distributions. Similarly, recent spatially unresolved X-ray observations have provided critical new insights into the toroidal obscurer and scatterer, potentially requiring a reinterpretation of long-established concepts. The first ALMA observations, for their part, have led to contradicting interpretations: either the molecular gas emission is indeed dominated by a rotating torus structure, or it is dominated by outflows, which would be more compatible with the elongated dust shapes seen in the infrared. Together with a dramatic increase in computational power, these observations have triggered a renaissance in modelling of the nuclear material, with models for the first time trying to not only explain the SEDs but also the spatial distribution of the dusty and molecular material. Further observational results are expected to revolutionise this picture in the coming years through the increased spatial resolution and sensitivity of ALMA and JWST, as well as the new generation of high-resolution X-ray spectrometers such as XARM.

Main scientific topics: Torus structure, composition, and parameter space; inflow, outflow, and internal dynamics; reprocessing; variability; interplay between accretion disk and host environment; evolution.

Registration: The registration will open on July 1 through our website : www.torus2018.org