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1. WISDOM project – V. Resolving molecular gas in Keplerian rotation around the supermassive black hole in NGC 0383

   https://doi.org/10.1093/mnras/stz2598  

   North, Eve V. ; Davis, Timothy A. ; Bureau, Martin ; Cappellari, Michele ; Iguchi, Satoru ; Liu, Lijie ; Onishi, Kyoko ; Sarzi, Marc ; Smith, Mark D. ; Williams, Thomas G. ( September 2019 , Monthly Notices of the Royal Astronomical Society)

   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⊙/L$_{\odot ,\, \mathrm{F160W}}$ in the centre to 2.4 ± 0.3 M⊙$/\rm L_{\odot ,\, \mathrm{F160W}}$ 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. Thismore »work demonstrates that low-J CO emission can resolve gas very close to the SMBH ($\approx 140\, 000$ Schwarzschild radii) and hence that the molecular gas method is highly complimentary to megamaser observations, as it can probe the same emitting material.

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2. WISDOM project – XIV. SMBH mass in the early-type galaxies NGC 0612, NGC 1574, and NGC 4261 from CO dynamical modelling

   https://doi.org/10.1093/mnras/stad1119  

   Ruffa, Ilaria ; Davis, Timothy A. ; Cappellari, Michele ; Bureau, Martin ; Elford, Jacob ; Iguchi, Satoru ; Lelli, Federico ; Liang, Fu-Heng ; Liu, Lijie ; Lu, Anan ; et al ( May 2023 , Monthly Notices of the Royal Astronomical Society)

   We present a CO dynamical estimate of the mass of the supermassive black hole (SMBH) in three nearby early-type galaxies: NGC 0612, NGC 1574, and NGC 4261. Our analysis is based on Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 3–6 observations of the 12CO(2–1) emission line with spatial resolutions of 14–58 pc (0.01″–0.26″). We detect disc-like CO distributions on scales from ≲ 200 pc (NGC 1574 and NGC 4261) to ≈10 kpc (NGC 0612). In NGC 0612 and NGC 1574 the bulk of the gas is regularly rotating. The data also provide evidence for the presence of a massive dark object at the centre of NGC 1574, allowing us to obtain the first measure of its mass, MBH = (1.0 ± 0.2) × 108 M⊙ (1σ uncertainty). In NGC 4261, the CO kinematics is clearly dominated by the SMBH gravitational influence, allowing us to determine an accurate black hole mass of (1.62 ± 0.04) × 109 M⊙ (1σ uncertainty). This is fully consistent with a previous CO dynamical estimate obtained using a different modelling technique. Signs of non-circular gas motions (likely outflow) are also identified in the inner regions of NGC 4261. In NGC 0612, we are only able to obtain a (conservative) upper limit of MBH ≲ 3.2 × 109 M⊙. This has likely to be ascribed to the presence of a centralmore »CO hole (with a radius much larger than that of the SMBH sphere of influence), combined with the inability of obtaining a robust prediction for the CO velocity curve. The three SMBH mass estimates are overall in agreement with predictions from the MBH − σ* relation.

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3. Black Hole Mass Measurements of Early-type Galaxies NGC 1380 and NGC 6861 through ALMA and HST Observations and Gas-dynamical Modeling*

   https://doi.org/10.3847/1538-4357/ac7a38  

   Kabasares, Kyle M. ; Barth, Aaron J. ; Buote, David A. ; Boizelle, Benjamin D. ; Walsh, Jonelle L. ; Baker, Andrew J. ; Darling, Jeremy ; Ho, Luis C. ; Cohn, Jonathan ( August 2022 , The Astrophysical Journal)

   Abstract We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 2 observations of CO(2–1) emission from the circumnuclear disks in two early-type galaxies, NGC 1380 and NGC 6861. The disk in each galaxy is highly inclined ( i ∼ 75°), and the projected velocities of the molecular gas near the galaxy centers are ∼300 km s −1 in NGC 1380 and ∼500 km s −1 in NGC 6861. We fit thin disk dynamical models to the ALMA data cubes to constrain the masses of the central black holes (BHs). We created host galaxy models using Hubble Space Telescope images for the extended stellar mass distributions and incorporated a range of plausible central dust extinction values. For NGC 1380, our best-fit model yields M BH = 1.47 × 10 8 M ⊙ with a ∼40% uncertainty. For NGC 6861, the lack of dynamical tracers within the BH’s sphere of influence due to a central hole in the gas distribution precludes a precise measurement of M BH . However, our model fits require a value for M BH in the range of (1–3) × 10 9 M ⊙ in NGC 6861 to reproduce the observations. The BH masses are generally consistent with predictionsmore »from local BH–host galaxy scaling relations. Systematic uncertainties associated with dust extinction of the host galaxy light and choice of host galaxy mass model dominate the error budget of both measurements. Despite these limitations, the measurements demonstrate ALMA’s ability to provide constraints on BH masses in cases where the BH’s projected radius of influence is marginally resolved or the gas distribution has a central hole.« less
4. WISDOM Project – XIII. Feeding molecular gas to the supermassive black hole in the starburst AGN-host galaxy Fairall 49

   https://doi.org/10.1093/mnras/stac2493  

   Lelli, Federico ; Davis, Timothy A. ; Bureau, Martin ; Cappellari, Michele ; Liu, Lijie ; Ruffa, Ilaria ; Smith, Mark D. ; Williams, Thomas G. ( September 2022 , Monthly Notices of the Royal Astronomical Society)

   The mm-Wave Interferometric Survey of Dark Object Masses (WISDOM) is probing supermassive black holes (SMBHs) in galaxies across the Hubble sequence via molecular gas dynamics. We present the first WISDOM study of a luminous infrared galaxy with an active galactic nuclei (AGNs): Fairall 49. We use new ALMA observations of the CO(2 − 1) line with a spatial resolution of ∼80 pc together with ancillary HST imaging. We reach the following results: (1) The CO kinematics are well described by a regularly rotating gas disc with a radial inflow motion, suggesting weak feedback on the cold gas from both AGN and starburst activity; (2) The dynamically inferred SMBH mass is 1.6 ± 0.4(rnd) ± 0.8(sys) × 108 M⊙ assuming that we have accurately subtracted the AGN and starburst light contributions, which have a luminosity of ∼109 L⊙; (3) The SMBH mass agrees with the SMBH−stellar mass relation but is ∼50 times higher than previous estimates from X-ray variability; (4) The dynamically inferred molecular gas mass is 30 times smaller than that inferred from adopting the Galactic CO-to-H2 conversion factor (XCO) for thermalized gas, suggesting low values of XCO; (5) the molecular gas inflow rate increases steadily with radius and may be as high as ∼5 M⊙ yr−1. This work highlights themore »potential of using high-resolution CO data to estimate, in addition to SMBH masses, the XCO factor, and gas inflow rates in nearby galaxies.

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5. The multiphase gas structure and kinematics in the circumnuclear region of NGC 5728

   https://doi.org/10.1093/mnras/stz2802  

   Shimizu, T. Taro ; Davies, R. I. ; Lutz, D. ; Burtscher, L. ; Lin, M. ; Baron, D. ; Davies, R. L. ; Genzel, R. ; Hicks, E. K. S. ; Koss, M. ; et al ( October 2019 , Monthly Notices of the Royal Astronomical Society)

   We report on our combined analysis of HST, VLT/MUSE, VLT/SINFONI, and ALMA observations of the local Seyfert 2 galaxy, NGC 5728 to investigate in detail the feeding and feedback of the active galactic nucleus (AGN). The data sets simultaneously probe the morphology, excitation, and kinematics of the stars, ionized gas, and molecular gas over a large range of spatial scales (10 pc to 10 kpc). NGC 5728 contains a large stellar bar that is driving gas along prominent dust lanes to the inner 1 kpc where the gas settles into a circumnuclear ring. The ring is strongly star forming and contains a substantial population of young stars as indicated by the lowered stellar velocity dispersion and gas excitation consistent with H ii regions. We model the kinematics of the ring using the velocity field of the CO (2–1) emission and stars and find it is consistent with a rotating disc. The outer regions of the disc, where the dust lanes meet the ring, show signatures of inflow at a rate of 1 M$\odot$ yr−1. Inside the ring, we observe three molecular gas components corresponding to the circular rotation of the outer ring, a warped disc, and the nuclear stellar bar. The AGN is driving an ionized gasmore »outflow that reaches a radius of 250 pc with a mass outflow rate of 0.08 M$\odot$ yr−1 consistent with its luminosity and scaling relations from previous studies. While we observe distinct holes in CO emission which could be signs of molecular gas removal, we find that largely the AGN is not disrupting the structure of the circumnuclear region.

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