Scientist find dense disk and torus funnel at Circinus galaxy's center

Researchers have obtained the most detailed view so far of the warm dust in the environment of a supermassive black hole in an active galaxy.

An international research team led by Konrad Tristram from the Max-Planck-Institute for Radio Astronomy in Bonn, Germany found that the dust directly illuminated by the central engine of the Circinus Galaxy is located in two distinct components: an inner warped disk and a surrounding larger distribution of dust.

Using the MIDI instrument at the Very Large Telescope Interferometer of the European Southern Observatory (ESO) in the Atacama Desert of Chile, the research team obtained an unprecedented clear view of the warm dust in the nucleus of the Circinus Galaxy. At a distance of only 13 million light-years, the Circinus Galaxy contains one of the closest and brightest active galactic nuclei.

In the case of the Circinus Galaxy, the scientists could, for the first time, show that the emission of the nuclear dust comes from two distinct components, an inner disk-like component and an extended component significantly elongated in polar direction. The dust disk in the Circinus Galaxy has a size of about 3 light-years and agrees well with a warped molecular disk revealed by water emission.

This inner disk is surrounded by a much bigger dust distribution with a size of at least 6 light-years. We only see the inner edge of this dust distribution, which is directly illuminated by the radiation coming from the central region. This inner funnel appears elongated in polar direction. Its southeastern side is significantly more obscured by dust than the northwestern side. This leads to the observed strong asymmetry and color change in the observed emission.

The results have been published in journal Astronomy and Astrophysics.