WISDOM project – V. Resolving molecular gas in Keplerian rotation around the supermassive black hole in NGC 0383
Journal article, 2019

As part of the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM), we present a measurement of the mass of the supermassive black hole (SMBH) in the nearby early-type galaxy NGC 0383 (radio source 3C 031). This measurement is based on Atacama Large Millimeter/sub-millimeter Array (ALMA) cycle 4 and 5 observations of the 12CO(2–1) emission line with a spatial resolution of 58 × 32 pc2 (0.18 arcsec × 0.1 arcsec). This resolution, combined with a channel width of 10 km s−1, allows us to well resolve the radius of the black hole sphere of influence (measured as RSOI = 316 pc = 0.98 arcsec), where we detect a clear Keplerian increase of the rotation velocities. NGC 0383 has a kinematically relaxed, smooth nuclear molecular gas disc with weak ring/spiral features. We forward model the ALMA data cube with the KINEMATIC MOLECULAR SIMULATION (KinMS) tool and a Bayesian Markov Chain Monte Carlo method to measure an SMBH mass of (4.2 ± 0.7) × 109 M, a F160W-band stellar mass-to-light ratio that varies from 2.8 ± 0.6 M/LF160W in the centre to 2.4 ± 0.3 M/LF160W at the outer edge of the disc and a molecular gas velocity dispersion of 8.3 ± 2.1 km s−1(all 3σ uncertainties). We also detect unresolved continuum emission across the full bandwidth, consistent with synchrotron emission from an active galactic nucleus. This work demonstrates that low-J CO emission can resolve gas very close to the SMBH (≈ 140 000 Schwarzschild radii) and hence that the molecular gas method is highly complimentary to megamaser observations, as it can probe the same emitting material.

Galaxies: kinematics and dynamics

Galaxies: elliptical and lenticular

Galaxies: ISM

Galaxies: individual: NGC 0383

Galaxies: nuclei


Eve V. North

Cardiff University

Timothy A. Davis

Cardiff University

M. Bureau

Yonsei University

University of Oxford

Michele Cappellari

University of Oxford

Satoru Iguchi

The Graduate University for Advanced Studies (SOKENDAI)

National Astronomical Observatory of Japan

Lijie Liu

University of Oxford

Kyoko Onishi

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Extragalactic Astrophysics

Ehime University

Marc Sarzi

Armagh Observatory and Planetarium

Mark D. Smith

University of Oxford

Thomas G. Williams

Cardiff University

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 490 1 319-330

Subject Categories

Subatomic Physics

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics


Onsala Space Observatory



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