How to Fuel an AGN: Mapping Circumnuclear Gas in NGC 6240 with ALMA

Abstract

Dynamical black hole mass measurements in some gas-rich galaxy mergers indicate that they are overmassive relative to their host galaxy properties. Overmassive black holes in these systems present a conflict with the standard progression of galaxy merger - quasar evolution; an alternative explanation is that a nuclear concentration of molecular gas driven inward by the merger is affecting these dynamical black hole mass estimates. We test for the presence of such gas near the two black holes in NGC 6240 using long-baseline ALMA Band 6 observations (beam size 0"06 $\times$ 0"03 or 30 pc$\times$15 pc). We find (4.2-9.8) $\times 10^7$ M${}_{\odot }$ and (1.2-7.7) $\times 10^8$ M${}_{\odot }$ of molecular gas within the resolution limit of the original black hole mass measurements for the north and south black holes, respectively. In the south nucleus, this measurement implies that 6-89% of the original black hole mass measurement actually comes from molecular gas, resolving the tension in the original black hole scaling relations. For the north, only 5% to 11% is coming from molecular gas, suggesting the north black hole is actually overmassive. Our analysis provides the first measurement of significant molecular gas masses contaminating dynamical black hole mass measurements. These high central molecular gas densities further present a challenge to theoretical black hole accretion prescriptions, which often assume accretion proceeds rapidly through the central 10 pc.

arXiv commentaccepted to ApJL

References in corpus (46)

• A Fundamental Relation Between Supermassive Black Holes and Their Host Galaxies
• The Demography of Massive Dark Objects in Galaxy Centres
• A Relationship Between Nuclear Black Hole Mass and Galaxy Velocity Dispersion
• The slope of the black-hole mass versus velocity dispersion correlation
• Modeling feedback from stars and black holes in galaxy mergers
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results
• The Relation between Black Hole Mass, Bulge Mass, and Near-Infrared Luminosity
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity
• Rotating Nuclear Rings and Extreme Starbursts in Ultraluminous Galaxies
• The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• A Cosmology Calculator for the World Wide Web
• Discovery of a binary AGN in the ultraluminous infrared galaxy NGC 6240 using Chandra
• ISM masses and the star formation law at Z = 1 to 6 // ALMA observations of dust continuum in 145 galaxies in the COSMOS survey field
• Measuring the inclination and mass-to-light ratio of axisymmetric galaxies via anisotropic Jeans models of stellar kinematics
• Rapid Formation of Supermassive Black Hole Binaries in Galaxy Mergers with Gas
• ALMA resolves the torus of NGC 1068: continuum and molecular line emission
• Counterrotating Nuclear Disks in Arp 220
• Infrared to millimetre photometry of ultra-luminous IR galaxies: new evidence favouring a 3-stage dust model
• ALMA observations of molecular tori around massive black holes
• Radiation-driven Fountain and Origin of Torus around Active Galactic Nuclei
• Evidence for CO shock excitation in NGC 6240 from Herschel SPIRE spectroscopy
• High-Velocity Bipolar Molecular Emission from an AGN Torus
• ALMA Reveals an Inhomogeneous Compact Rotating Dense Molecular Torus at the NGC 1068 Nucleus
• ALMA Imaging of HCN, CS and dust in Arp 220 and NGC 6240
• ALMA Resolves the Nuclear Disks of Arp 220
• Circumnuclear Multi-phase Gas in the Circinus Galaxy II: The Molecular and Atomic Obscuring Structures Revealed with ALMA
• Multi-phase Nature of a Radiation-Driven Fountain with Nuclear Starburst in a Low-mass Active Galactic Nucleus
• Resolving the nuclear obscuring disk in the Compton-thick Seyfert galaxy NGC5643 with ALMA
• WISDOM Project - II: Molecular gas measurement of the supermassive black hole mass in NGC4697
• ALMA [CI]${}^3{P}_1{-}^3{P}_0$ observations of NGC6240: a puzzling molecular outflow, and the role of outflows in the global ${\alpha }_{\mathrm{CO}}$ factor of (U)LIRGs
• Parsec-Scale Radio Structure of the Double Active Nucleus of NGC 6240
• A nuclear molecular outflow in the Seyfert galaxy NGC3227
• Stellar and Gaseous Nuclear Disks Observed in Nearby (U)LIRGs
• The Accretion Disc Particle Method for Simulations of Black Hole Feeding and Feedback
• Hubble Space Telescope ACS Imaging of the GOALS Sample: Quantitative Structural Properties of Nearby Luminous Infrared Galaxies with L_IR > 10^{11.4} L_sun
• WISDOM Project - III: Molecular gas measurement of the supermassive black hole mass in the barred lenticular galaxy NGC4429
• Measurement of the Black Hole Mass in NGC 1332 from ALMA Observations at 0.044 Arcsecond Resolution
• The Core of NGC 6240 from Keck Adaptive Optics and HST NICMOS Observations
• The Radio Emission from the Ultra-Luminous Far-Infrared Galaxy NGC 6240
• The hard X-ray emission of the luminous infrared galaxy NGC 6240 as observed by NuSTAR
• A Precision Measurement of the Mass of the Black Hole in NGC 3258 from High-Resolution ALMA Observations of its Circumnuclear Disk
• Mass of the Southern Black Hole in NGC 6240 from Laser Guide Star Adaptive Optics
• Following Black Hole Scaling Relations Through Gas-Rich Mergers
• Imaging the Molecular Outflows of the Prototypical ULIRG NGC 6240 with ALMA
• Phase correction for ALMA - Investigating water vapour radiometer scaling:The long-baseline science verification data case study
• Accretion Disc Particle Accretion in Major Merger Simulations

Cited by in corpus (11)

• Revealing the intermediate-mass black hole at the heart of the dwarf galaxy NGC 404 with sub-parsec resolution ALMA observations
• The Molecular Gas in the NGC 6240 Merging Galaxy System at the Highest Spatial Resolution
• GOALS-JWST: Gas Dynamics and Excitation in NGC7469 revealed by NIRSpec
• Revisiting the complex nuclear region of NGC 6240 with Chandra
• The Role of AGN in Luminous Infrared Galaxies from the Multiwavelength Perspective
• A Multi-wavelength Study of the Dual Nuclei in Mrk 212
• Subaru Infrared Adaptive Optics-assisted High-spatial-resolution Imaging Search for Luminous Dual Active Galactic Nuclei in Nearby Ultraluminous Infrared Galaxies
• A possible relation between global CO excitation and massive molecular outflows in local ULIRGs
• Outflowing shocked gas dominates the NIR H${}_2$ emission from the dual AGN NGC6240
• Constraining Nuclear Molecular Gas Content with High-resolution CO Imaging of GOALS Galaxies
• The Relationship Between Eddington Ratio and Column Density in U/LIRG AGN