ALMA uncovers optically thin and multi-component CO gas in the outflowing circumnuclear disk of NGC1068

Abstract

Active galactic nuclei (AGNs) influence their host galaxies through winds and jets that can drive molecular outflows, traceable with CO line emissions using the Atacama Large Millimeter Array (ALMA). Recent studies leveraging ALMA data have proposed a three-dimensional outflow geometry in the nearby Seyfert II galaxy NGC 1068, a key target for AGN unification theories. Using ALMA observations of CO(2-1), CO(3-2), and CO(6-5) transitions at roughly 0.1 arcseconds (approximately 7 parsecs) resolution, we analyzed the temperature, density, and kinematics of NGC 1068's circumnuclear disk (CND), focusing on the molecular outflow. Through local thermodynamic equilibrium (LTE) analysis, we derived column densities and rotational temperatures, indicating optically thin gas and CO-to-H2 (XCO) conversion factors between 4.8 and 9.6 times smaller than the Milky Way value. The inferred molecular mass outflow rate is mostly below 5.5 solar masses per year, with the dominant contribution northeast of the AGN. After subtracting the rotation curve of the CND, we modeled averaged line profiles in each region using single and multi-component Gaussian fits. Several profiles within or near the AGN wind bicone required multiple components with significant velocity shifts, suggesting multi-component complex outflow kinematics. We observe lateral variation in CO kinematics along the AGN wind bicone and a misalignment between the molecular and ionized outflow directions. These results imply that the dynamic impact of the ionized AGN wind on the molecular gas in the CND may be limited. However, the molecular outflow shows a complex, asymmetric structure.

Accepted for publication in A&A (manuscript ID: aa53704-25)

References in corpus (19)

• CASA, the Common Astronomy Software Applications for Radio Astronomy
• Molecular line emission in NGC1068 imaged with ALMA. I An AGN-driven outflow in the dense molecular gas
• Star formation in a galactic outflow
• A Survey of Kiloparsec-Scale Radio Outflows in Radio-Quiet Active Galactic Nuclei
• 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
• ALMA images the many faces of the NGC1068 torus and its surroundings
• Kinematics of the Narrow-Line Region in the Seyfert 2 Galaxy NGC 1068: Dynamical Effects of the Radio Jet
• MAGNUM survey: Compact jets causing large turmoil in galaxies -- Enhanced line widths perpendicular to radio jets as tracers of jet-ISM interaction
• High-Velocity Bipolar Molecular Emission from an AGN Torus
• Parsec-scale dust distributions in Seyfert galaxies - Results of the MIDI AGN snapshot survey
• ALMA reveals optically thin, highly excited CO gas in the jet-driven winds of the galaxy IC5063
• CI and CO in nearby galaxy centers: the bright galaxies NGC1068 (M77), NGC2146, NGC3079, NGC4826 (M64), and NGC7469
• Modeling the [Fe II]λ1.644μm outflow and comparison with H${}_2$ and H${}^{+}$ kinematics in the inner 200 pc of NGC 1068
• The HII Galaxy Hubble Diagram Strongly Favors $R_{\mathrm{h}}=ct$ over $\Lambda$CDM
• ALMA imaging of C2H emission in the disk of NGC1068
• A two-stage outflow in NGC 1068
• ALMA resolves the remarkable molecular jet and rotating wind in the extremely radio-quiet galaxy NGC 1377
• Tracing the outflow kinematics in Type 2 Active Galactic Nuclei