High Sensitivity Observations of the Water Megamasers of NGC 1068: Precise Astrometry and Detailed Kinematics

Abstract

We present High Sensitivity Array observation of the water megamasers of NGC 1068. We obtain absolute astrometry with 0.3 mas precision that confirms the association of the disk masers with the nuclear radio continuum source S1. The new observations reveal two new blueshifted groups of disk masers. We also detect the 22 GHz continuum on short interferometric baselines. The position-velocity diagram of the disk masers shows a curve consistent with a nonaxisymmetric distribution of maser spots. The curve is probably the result of spiral arms with a constant pitch angle of roughly 5 degrees. The disk kinematics are consistent with Keplerian rotation and low turbulent speeds. The inferred central mass is 17 million solar masses. On the basis of disk stability arguments, the mass of the molecular disk is roughly 110 thousand solar masses. The disk masers further resolve into filamentary structures suggesting an ordered magnetic field threading the maser disk. The magnetic field strengths must be greater than 1.6 mG to withstand turbulent motions in the partially ionized molecular gas. We note apparent asymmetries in the molecular disk that might be explained by anisotropic heating by a misaligned inner accretion disk. The new observations also detect the fainter jet masers north of the disk masers. The distribution and kinematics of the jet masers are consistent with an expanding ring of molecular gas.

arXiv commentAccepted for publication in the Astrophysical Journal. 36 pages, 22 figures

References in corpus (35)

• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• Revisiting the Unified Model of Active Galactic Nuclei
• The Relation Between Optical Extinction and Hydrogen Column Density in the Galaxy
• Gravitational Instabilities in Circumstellar Disks
• Filamentary structure of star-forming complexes
• A 4% Geometric Distance to the Galaxy NGC4258 from Orbital Motions in a Nuclear Gas Disk
• Data analysis recipes: Using Markov Chain Monte Carlo
• Toward a New Geometric Distance to the Active Galaxy NGC 4258. III. Final Results and the Hubble Constant
• The Megamaser Cosmology Project. III. Accurate Masses of Seven Supermassive Black Holes in Active Galaxies with Circumnuclear Megamaser Disks
• VLBI Imaging of Water Maser Emission from the Nuclear Torus of NGC 1068
• Distances to PHANGS Galaxies: New Tip of the Red Giant Branch Measurements and Adopted Distances
• The Parsec-scale Radio Structure of NGC 1068 and the Nature of the Nuclear Radio Source
• Non-Keplerian rotation in the nucleus of NGC 1068: evidence for a massive accretion disk?
• Amplification, Saturation, and Q Thresholds for Runaway: Growth of Self-Gravitating Structures in Models of Magnetized Galactic Gas Disks
• High-Velocity Bipolar Molecular Emission from an AGN Torus
• The Nature of the Nuclear H2O Masers of NGC 1068: Reverberation and Evidence for a Rotating Disk Geometry
• Astrometric accuracy of phase-referenced observations with the VLBA and EVN
• An image of the dust sublimation region in the nucleus of NGC 1068
• Counter-Rotation and High Velocity Outflow in the Parsec-Scale Molecular Torus of NGC 1068
• Thermal imaging of dust hiding the black hole in the Active Galaxy NGC 1068
• The Megamaser Cosmology Project VIII. A Geometric Distance to NGC 5765b
• The Megamaser Cosmology Project.IX. Black hole masses for three maser galaxies
• Origin of non-keplerian motions of masers in NGC 1068
• The structure of the central disk of NGC 1068: a clumpy disk model
• A two-stage outflow in NGC 1068
• Polarimetric Observations of the Masers in NGC 4258: An Upper Limit on the Large-Scale Magnetic Field 0.2 pc from the Central Engine
• Near-Infrared Polarimetric Adaptive Optics Observations of NGC 1068: A torus created by a hydromagnetic outflow wind
• ALMA polarimetry measures magnetically aligned dust grains in the torus of NGC 1068
• Enhancing the H2O Megamaser Detection Rate Using Optical and Mid-infrared Photometry
• Spiral Structure In The Circum-nuclear Disk At The Center Of The Galaxy NGC 4258
• Characterizing maser polarization: effects of saturation, anisotropic pumping and hyperfine structure
• Response of circumnuclear water masers to luminosity changes in an active galactic nucleus
• Stretching of the toroidal field and generation of magnetosonic waves in differentially rotating plasma
• High-sensitivity VLBI Observations of the Water Masers in the Seyfert Galaxy NGC 1068

Cited by in corpus (6)

• Deciphering the imprint of AGN feedback in Seyfert galaxies: Nuclear-scale molecular gas deficits
• Direct imaging of AGN outflows and their origin with the 23 m Large Binocular Telescope
• Chromatically modelling the parsec scale dusty structure in the centre of NGC1068
• Partial alignment between jets and megamasers: Coherent versus selective accretion
• Water Maser Disk and a Supermassive Black Hole at the Nucleus of the Active Galaxy NGC 7738
• High resolution mapping of molecular tori with ALMA