The emission from the nucleus of an active galaxy arises as a supermassive black hole at the center is fed with gas and dust from the main part of the galaxy. Galactic nuclear spiral arms, which are several hundred lightyears long, have been postulated to be the missing link between the dynamics of the galaxy disk and the central activity, since the arms channel matter down to the black hole. The nuclear spiral arms differ from the regular large-scale spiral arms, which extend tens of thousands of lightyears, and are difficult to identify, because they are in comparison considerably less bright, form a lot less stars and have more chaotic appearances.

In a new article, Glenn van de Ven (Institute for Advanced studies, Princeton, USA) and Kambiz Fathi (Department of Astronomy, Stockholm University) have shown that kinematic mapping of the velocities in the nuclear spiral arms can give a much deeper insight into how they function. In addition to an analysis of the arms' structure, the reseachers have calculated how large the gas inflow is along the arms down towards the supermassive black hole in the active galaxy NGC 1097. The study has opened a new window to the activity at the center of active galaxies.

Original article:
Kinematic analysis of nuclear spirals: feeding the black hole in NGC1097 Contact:

Kambiz Fathi, Tel: 08-5537 8521, kambiz@astro.su.se