The warped disk of Centaurus A from a radius of 2 to 6500pc

Abstract

We compile position and inclination angles for tilted ring fits to the warped dusty and gaseous disk of CenA, spanning a radius of 1.8 to 6500pc, from recent observations. For radii exterior to 1kpc, tilted-ring orientations lie on an arc, on a plot of polar-inclination versus position-angle, suggesting that precession following a merger can account for the ring morphology. Three kinks in the ring orientations are seen on the polar plot, the one at radius of about 1.3kpc we suspect corresponds to the location where self-gravity in the disk affects the ring precession rate. Another at a radius of about 600pc may be associated with a gap in the gas distribution. A third kink is seen at a radius of 100pc. A constant inclination tilted disk precessing about the jet axis may describe the disk between 100 and 20pc but not interior to this. A model with disk orientation matching the molecular circumnuclear disk at 100pc that decays at smaller radii to an inner flat disk perpendicular to the jet may account for disk orientations within 100pc. Neither model would account for the cusps or changes in disk orientation at 100 or 600pc. © Astronomical Society of Australia 2010.