Daily Image

22-04-2010
PreviousNext
Click here or on the picture for a full size image.

An HI absorbing circumnuclear disk in Cygnus A

Submitter: Christian Struve
Description: Cygnus A is the closest powerful radio galaxy. Very Long Baseline Array (VLBA) observations have revealed the structure of the neutral gas (HI) close to the supermassive black hole, which is detected against the radio continuum. The above image (top panel) shows the radio continuum of the nucleus, the jet (to the right) and a counter-jet (to the left). HI absorption is detected mainly against the beginning counter-jet (bottom right figure); the spectrum is shown in the bottom left figure. The gas appears to come from a circumnuclear disk that is roughly perpendicular to the jet axis at a radius of 250 light years. This disk is larger than the inner "torus" structure that is obscuring the black hole, but it could be the gas reservoir that is needed to feed the black hole and replenish the torus.

The above results are summarized in a paper that was recently published in Astronomy & Astrophysics entitled: "An HI absorbing circumnuclear disk in Cygnus A" by C. Struve and J.E. Conway, volume 513, A10. A preprint of the paper can be found here: http://arxiv.org/abs/0910.5705
Copyright: Astron
 
  Follow us on Twitter
Please feel free to submit an image using the Submit page.