Contribution
Molecular gas imaging of the circumnuclear environs of Centaurus A
Presenter: Daniel Espada (Harvard-Smithsonian Center for Astrophysics)
Abstract: We have imaged with unprecedented resolution (6 × 2 arcsec, 100 × 30 pc) the molecular gas along the dust lane of Centaurus A, as traced by the CO(2→1) line observed using the Submillimeter Array (SMA). We spatially resolve the circumnuclear molecular gas in the inner r < 200 pc, elongated along a P.A. = 155°, just perpendicular to the X-ray / radio jet, as well as a more extended component coextensive with the parallelogram structure observed in dust emission at P.A. = 120°. Towards the nuclear 1.3 mm continuum emission arising from the AGN, CO(2→1) absorption features are also detected with minimized contamination by emission, which allow us to have a further insight into the bulk of molecular gas in the line of sight. We use this information in order to constrain a physical model that successfully reproduces the main observed features, including a physical connection between the circumnuclear gas and that at larger radii, brighter SE and NW sides on the parallelogram-shaped feature, and an outer curvature of its long sides. We discuss about a possible contribution of a weak bi-symmetric potential which would explain these peculiarities.