Torus feeding and outflow launching in the active nucleus of the Circinus galaxy

Abstract

Context: Most active galactic nuclei (AGN) are believed to be surrounded by a dusty molecular torus on the parsec scale which is often embedded within a larger circumnuclear disk (CND). AGN are fuelled by the inward transport of material through these structures and can launch multi-phase outflows that influence the host galaxy through AGN feedback. Aims: We use the Circinus Galaxy as a nearby laboratory to investigate the physical mechanisms responsible for feeding the torus and launching a multi-phase outflow in this Seyfert-type AGN, as these mechanisms remain poorly understood. Methods: We analysed observations from the Atacama Large Millimeter/submillimeter Array of the Circinus nucleus at angular resolutions down to 13 mas (0.25 pc). We traced dust and the ionised outflow using 86-665 GHz continuum emission, and studied the morphology and kinematics of the molecular gas. Results: We find that the Circinus CND hosts molecular and dusty spiral arms, two of which connect directly to the torus. We detect inward mass transport along these structures and argue that the non-axisymmetric potential generated by these arms is the mechanism responsible for fuelling the torus. We estimate a feeding rate of 0.3-7.5 M${}_{\odot }$yr${}^{-1}$, implying that over 88% of the inflowing material is expelled in a multi-phase outflow before reaching the accretion disk. The inferred torus feeding time scale (120 kyr - 2.7 Myr) suggests that variability in AGN activity may be driven by changes in torus feeding. On parsec scales, the ionised outflow is traced by optically thin free-free emission. The outflow is stratified, with a slightly wider opening angle in the molecular phase than in the dusty and ionised components. The ionised outflow is launched or collimated by a warped accretion disk at a radius of r ~ 0.16 pc, and its geometry requires an anisotropic launching mechanism.

References in corpus (25)

• CASA, the Common Astronomy Software Applications for Radio Astronomy
• The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
• Resolving the complex structure of the dust torus in the active nucleus of the Circinus galaxy
• Observational Constraints on the Feeding of Supermassive Black Holes
• Molecular line emission in NGC1068 imaged with ALMA: II. The chemistry of the dense molecular gas
• Multi-phase Nature of a Radiation-Driven Fountain with Nuclear Starburst in a Low-mass Active Galactic Nucleus
• SINFONI adaptive optics integral field spectroscopy of the Circinus Galaxy
• Dissecting the active galactic nucleus in Circinus -- I. Peculiar mid-IR morphology explained by a dusty hollow cone
• Search and modelling of remnant radio galaxies in the LOFAR Lockman Hole field
• Analysis of spiral arms using anisotropic wavelets: gas, dust and magnetic fields in M51
• Dissecting the active galactic nucleus in Circinus -- II. A thin dusty disc and a polar outflow on parsec scales
• On the origin of radio core emission in radio-quiet quasars
• BASS XXXII: Studying the Nuclear Mm-wave Continuum Emission of AGNs with ALMA at Scales $\lesssim$ 100-200 pc
• A Tight Correlation Between Millimeter and X-ray Emission in Accreting Massive Black Holes from <100 Milliarcsecond-resolution ALMA Observations
• The dusty heart of Circinus: I. Imaging the circumnuclear dust in N-band
• AGN feeding and feedback in Fornax A: kinematical analysis of the multi-phase ISM
• The Molecular Wind in the Nearest Seyfert Galaxy Circinus Revealed by ALMA
• Supermassive black hole feeding and feedback observed on sub-parsec scales
• A multiwavelength-motivated X-ray model for the Circinus Galaxy
• ALMA imaging of the cold molecular and dusty disk in the type 2 active nucleus of the Circinus galaxy
• The ionised gas outflow in the Circinus galaxy: kinematics and physical conditions
• Statistics on 24 spiral galaxies having different observed arm locations using different arm tracers
• Dissecting the active galactic nucleus in Circinus IV. MUSE NFM observations unveil a tuning-fork ionised gas morphology
• The life cycle of starbursting circumnuclear gas discs
• Decoding the molecular torus of NGC 1068: Insights into its structure and kinematics from high-resolution ALMA observations