New active galactic nuclei science cases with interferometry

Sebastian F Hönig,Konrad R W Tristram,Jörg-Uwe Pott,Almudena Alonso Herrero,Poshak Gandhi,Jean Surdej,Makoto Kishimoto,Cristina Ramos Almeida

doi:10.1007/s10686-018-9612-3

Abstract

Infrared (IR) interferometry has made widely recognised contributions to the way we look at the dusty environment of supermassive black holes on parsec scales. It finally provided direct evidence for orientation-dependent unification of active galaxies, however it also showed that the classical “torus” picture is oversimplified. New scientific opportunities for AGN have been suggested, and will soon be carried out, focusing on the dynamical aspects of spectrally and spatially resolved interferometry, as well as the potential to employ interferometry for cosmology. This will open interferometry to new scientific communities.

Highlights

Long-baseline infrared (IR) interferometry is a rather young technique for extragalactic science
Infrared (IR) interferometry has made widely recognised contributions to the way we look at the dusty environment of supermassive black holes on parsec scales
With the help of the growing sample of AGN observed with MIDI, it was realised that the dusty environment among different objects is quite diverse [2, 11]

Summary

The past ten years: the dusty environment of active galactic nuclei

Long-baseline infrared (IR) interferometry is a rather young technique for extragalactic science. These studies targeted the two IR-brightest AGN in the sky: NGC4151 in the northern hemisphere with the Keck interferometer and NGC1068 in the south with the VLTI Even with those large-scale facilities, observing new objects remains challenging up to today since the field is mostly sensitivity limited. The major focus of the first decade of extragalactic long-baseline interferometry was the study of the dusty environment of actively accreting supermassive black holes in the centres of galaxies. A new disk+wind model was introduced that is able to simultaneously reproduce IR SED and interferometry of AGN [9] If confirmed, this represents a significant shift of paradigm in the field of AGN. Observational and theoretical efforts into this direction are ongoing (e.g. [1, 21])

New scientific pathways for the next decade

Near-term science: toward a new paradigm for the dust distribution around AGN

Near-term science: unveiling the black hole in the centre of the Milkyway

Mid-term science

Mid-term science goal: dynamical black hole mass measurements in the local universe and beyond

Summary and conclusions