Highlight: An HI absorbing circumnuclear disk in Cygnus A (vol. 512)

Vol. 512In section 4. Extragalactic astronomy16 April 2010

An HI absorbing circumnuclear disk in Cygnus A

by C. Struve and J.E. Conway, A&A 513, A10

Very Long Baseline Array (VLBA) observations have revealed the structure of the neutral gas with 25 milli-arcsec resolution, which is absorbing in the radio continuum of the core and jets of the powerful radio galaxy Cygnus A 21cm. The HI gas appears to come from a circumnuclear disk perpendicular to the jet axis at a radius of 80 pc. This disk is larger than the obscuring torus of 3pc radius, but it also contributes to the obscuration. While the torus does not have enough gas to fuel the AGN activity, the circumnuclear disk could be the reservoir to replenish the torus in gas and eventually fuel the AGN.