Disentangling the circumnuclear environs of Centaurus A: I. High resolution molecular gas imaging

Abstract

We present high resolution images of the 12CO(2-1) emission in the central 1' (1 kpc) of NGC 5128 (Centaurus A), observed using the SMA. We elucidate for the first time the distribution and kinematics of the molecular gas in this region with a resolution of 6'.0 x 2'.4 (100 pc x 40 pc). We spatially resolve the circumnuclear molecular gas in the inner 24'' x 12'' (400 pc x 200 pc), which is elongated along a position angle P.A. = 155 deg and perpendicular to the radio/X-ray jet. The SE and NW components of the circumnuclear gas are connected to molecular gas found at larger radii. This gas appears as two parallel filaments at P.A. = 120 deg, which are coextensive with the long sides of the 3 kiloparsec parallelogram shape of the previously observed dust continuum, as well as ionized and pure rotational H2 lines. Spatial and kinematical asymmetries are apparent in both the circumnuclear and outer gas, suggesting non-coplanar and/or non-circular motions. We extend to inner radii (r < 200 pc) previously studied warped disk models built to reproduce the central parallelogram-shaped structure. Adopting the warped disk model we would confirm a gap in emission between the radii r = 200 - 800 pc (12'' - 50''), as has been suggested previously. Although this model explains this prominent feature, however, our 12CO(2-1) observations show relevant deviations from this model. Namely, the 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. Overall it resembles more closely an S-shaped morphology, a trend that is also found in other molecular species. Hence, we explore qualitatively the possible contribution of a weak bi-symmetric potential which would naturally explain these peculiarities.

26 Pages, 14 Figures. Accepted for publication in ApJ

References in corpus (6)

• The central parsecs of Centaurus A: High Excitation Gas, a Molecular Disk, and the Mass of the Black Hole
• The Discovery of Cepheids and a Distance to NGC 5128
• Spitzer observations of the dusty warped disk of Centaurus A
• Integral-field spectroscopy of Centaurus A nucleus
• The millimeter-wave continuum spectrum of Centaurus A and its nucleus
• Spitzer IRS mapping of the central kpc of Centaurus A

Cited by in corpus (26)

• Polarimetric properties of Event Horizon Telescope targets from ALMA
• Centaurus A: morphology and kinematics of the atomic hydrogen
• HIFI Spectroscopy of ${\mathrm{H}}_2\mathrm{O}$ submm Lines in Nuclei of Actively Star Forming Galaxies
• Disentangling the Circumnuclear Environs of Centaurus A: III. An Inner Molecular Ring, Nuclear Shocks and the CO to warm H2 interface
• The many faces of the gas in Centaurus A (NGC5128)
• Star formation efficiency along the radio jet in Centaurus A
• The warm molecular gas and dust of Seyfert galaxies: two different phases of accretion?
• Resolving the nucleus of Centaurus A at mid-IR wavelengths
• Disentangling the circumnuclear environs of Centaurus A: II. On the nature of the broad absorption line
• Atomic-to-molecular gas phase transition triggered by the radio jet in Centaurus A
• The Magnetic Field Across the Molecular Warped Disk of Centaurus A
• Star Formation Efficiencies at Giant Molecular Cloud Scales in the Molecular Disk of the Elliptical Galaxy NGC 5128 (Centaurus A)
• The Warped Disk of Centaurus A from a radius of 2 to 6500 pc
• Complex distribution and velocity field of molecular gas in NGC 1316 as revealed by Morita Array of ALMA
• The outflow of gas from the Centaurus A circumnuclear disk: atomic spectral line maps from Herschel-PACS and APEX
• ALMA Observations of the Physical and Chemical Conditions in Centaurus A
• High-resolution mapping of the physical conditions in two nearby active galaxies based on 12CO(1-0), (2-1) and (3-2) lines
• Uncovering the kiloparsec-scale stellar ring of NGC5128
• The multi-phase environment in the centre of Centaurus A
• Is Centaurus A special? A neutral hydrogen perspective
• A Giant Molecular Cloud Catalog in the Molecular Disk of the Elliptical Galaxy NGC 5128 (Centaurus A)
• Molecular gas properties of galaxies: The SMA CO(2-1) B0DEGA legacy project
• 3.3 μm PAH observations of the central kiloparsecs of Centaurus A
• Multi-epoch X-ray spectral analysis of Centaurus A: revealing new constraints on iron emission line origins
• 10 pc Scale Circumnuclear Molecular Gas Imaging of Nearby AGNs
• MICONIC: JWST/MIRI-MRS reveals heavily reprocessed PAH emission in the circum-nuclear disc of Centaurus A