Much of the progress in astronomy has been driven by instrumental developments, from the
first telescopes to fiber fed spectrographs. In this review, we describe the field of …

Context. Optical interferometry is at a key development stage. The Very Large Telescope
Interferometer (VLTI) has established a stable, robust infrastructure for long-baseline …

Context. With infrared interferometry it is possible to resolve the nuclear dust distributions
that are commonly associated with the dusty torus in active galactic nuclei (AGN). The …

Context. Optical long-baseline interferometry is moving a crucial step forward with the
advent of general-user scientific instruments that equip large aperture and hectometric …

We collate the results of recent high resolution X-ray spectroscopic observations of 23 AGN,
and use the resulting information to try to provide answers to some of the main open …

Context. The AGN-heated dust distribution (the “torus”) is increasingly recognized not only
as the absorber required in unifying models, but as a tracer for the reservoir that feeds the …

Aims. To test the dust torus model for active galactic nuclei directly, we study the extent and
morphology of the nuclear dust distribution in the Circinus galaxy using high resolution …

With the possibilities of high spatial resolution imaging and spectroscopy as well as infrared
(IR) interferometry, the dusty environments (=“dusty torus”) of active galactic nuclei (AGN) …

Spatially resolving the innermost region of the putative torus-like structure in an active
galactic nucleus (AGN) is one of the main goals of high-spatial-resolution studies. This could …

We are now exploring the inner region of type 1 active galactic nuclei (AGNs) with the Keck
interferometer in the near-infrared. Adding to the four targets previously studied, we report …