WISDOM

Data Release One is now live!

2024-06-24T00:00:00+00:00

We are pleased to announce that WISDOM Data Release One is now live on the website.

Please head to the Data page to access to high-resolution datacubes and products for the first 25 galaxies (those studied in WISDOM paper X).

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WISDOM Project - XIX. Figures of merit for supermassive black hole mass measurements using molecular gas and/or megamaser kinematics

2024-05-07T00:00:00+00:00

Abstract
The mass (M_BH) of a supermassive black hole (SMBH) can be measured using spatially resolved kinematics of the region where the SMBH dominates gravitationally. The most reliable measurements are those that resolve the smallest physical scales around the SMBHs. We consider here three metrics to compare the physical scales probed by kinematic tracers dominated by rotation: the radius of the innermost detected kinematic tracer R_min normalized by the SMBH’s Schwarzschild radius (R_Schw ≡ 2GM_BH/c², where G is the gravitational constant and c the speed of light), sphere-of-influence (SOI) radius ($R_\mathrm{SOI}\equiv GM_\mathrm{BH}/\sigma _\mathrm{e}^2$, where σ_e is the stellar velocity dispersion within the galaxy’s effective radius), and equality radius [the radius R_eq at which the SMBH mass equals the enclosed stellar mass, M_BH = M_*(R_eq), where M_*(R) is the stellar mass enclosed within the radius R]. All metrics lead to analogous simple relations between R_min and the highest circular velocity probed V_c. Adopting these metrics to compare the SMBH mass measurements using molecular gas kinematics to those using megamaser kinematics, we demonstrate that the best molecular gas measurements resolve material that is physically closer to the SMBHs in terms of R_Schw but is slightly farther in terms of R_SOI and R_eq. However, molecular gas observations of nearby galaxies using the most extended configurations of the Atacama Large Millimeter/submillimeter Array can resolve the SOI comparably well and thus enable SMBH mass measurements as precise as the best megamaser measurements.

WISDOM Project - XIX. Figures of merit for supermassive black hole mass measurements using molecular gas and/or megamaser kinematics
Monthly Notices of the Royal Astronomical Society, 530, 3, 3240-3251
Zhang, Hengyue; Bureau, Martin; Smith, Mark D.; Cappellari, Michele; Davis, Timothy A.; Dominiak, Pandora; Elford, Jacob S.; Liang, Fu-Heng; Ruffa, Ilaria; Williams, Thomas G.
(ADS) / (arXiv)

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WISDOM project - XVIII. Molecular gas distributions and kinematics of three megamaser galaxies

2023-11-28T00:00:00+00:00

Abstract
The co-evolution of galaxies and supermassive black holes (SMBHs) underpins our understanding of galaxy evolution, but different methods to measure SMBH masses have only infrequently been cross-checked. We attempt to identify targets to cross-check two of the most accurate methods, megamaser, and cold molecular gas dynamics. Three promising galaxies are selected from all those with existing megamaser SMBH mass measurements. We present Atacama Large Millimeter/sub-millimeter Array (ALMA) ¹²CO(2-1) and 230-GHz continuum observations with angular resolutions of ≈0.5”. Every galaxy has an extended rotating molecular gas disc and 230-GHz continuum source(s), but all also have irregularities and/or non-axisymmetric features: NGC 1194 is highly inclined and has disturbed and lopsided central ¹²CO(2-1) emission; NGC 3393 has a nuclear disc with fairly regular but patchy ¹²CO(2-1) emission with little gas near the kinematic major axis, faint emission in the very centre, and two brighter structures reminiscent of a nuclear ring and/or spiral; NGC 5765B has a strong bar and very bright ¹²CO(2-1) emission concentrated along two bisymmetric offset dust lanes and two bisymmetric nuclear spiral arms. ¹²CO(2-1) and ¹²CO(3-2) observations with the James Clerk Maxwell Telescope are compared with the ALMA observations. Because of the disturbed gas kinematics and the impractically long integration times required for higher angular resolution observations, none of the three galaxies is suitable for a future SMBH mass measurement. None the less, increasing the number of molecular gas observations of megamaser galaxies is valuable, and the ubiquitous disturbances suggest a link between large-scale gas properties and the existence of megamasers.

WISDOM project - XVIII. Molecular gas distributions and kinematics of three megamaser galaxies
Monthly Notices of the Royal Astronomical Society, 527, 3, 9343-9358
Liang, Fu-Heng; Smith, Mark D.; Bureau, Martin; Gao, Feng; Davis, Timothy A.; Cappellari, Michele; Elford, Jacob S.; Greene, Jenny E.; Iguchi, Satoru; Lelli, Federico; Lu, Anan; Ruffa, Ilaria; Williams, Thomas G.; Zhang, Hengyue
(ADS) / (arXiv)

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WISDOM Project - XV. Giant molecular clouds in the central region of the barred spiral galaxy NGC 5806

2023-07-02T00:00:00+00:00

Abstract
We present high spatial resolution (≈24 pc) Atacama Large Millimeter/sub-millimeter Array ¹²CO(2-1) observations of the central region of the nearby barred spiral galaxy NGC 5806. NGC 5806 has a highly structured molecular gas distribution with a clear nucleus, a nuclear ring, and offset dust lanes. We identify 170 spatially and spectrally resolved giant molecular clouds (GMCs). These clouds have comparable sizes (R_c) and larger gas masses, observed linewidths (σ_{obs, los}), and gas mass surface densities than those of clouds in the Milky Way disc. The size-linewidth relation of the clouds is one of the steepest reported so far (σ_obs,los∝R_c^1.20), the clouds are on average only marginally bound (with a mean virial parameter ⟨α_vir⟩ ≈ 2), and high velocity dispersions are observed in the nuclear ring. These behaviours are likely due to bar-driven gas shocks and inflows along the offset dust lanes, and we infer an inflow velocity of ≈120 km s^-1 and a total molecular gas mass inflow rate of ≈5 M_⊙ yr^-1 into the nuclear ring. The observed internal velocity gradients of the clouds are consistent with internal turbulence. The number of clouds in the nuclear ring decreases with azimuthal angle downstream from the dust lanes without clear variation of cloud properties. This is likely due to the estimated short lifetime of the clouds (≈6 Myr), which appears to be mainly regulated by cloud-cloud collision and/or shear processes. Overall, it thus seems that the presence of the large-scale bar and gas inflows to the centre of NGC 5806 affect cloud properties.

WISDOM Project - XV. Giant molecular clouds in the central region of the barred spiral galaxy NGC 5806
Monthly Notices of the Royal Astronomical Society, 522, 3, 4078-4097
Choi, Woorak; Liu, Lijie; Bureau, Martin; Cappellari, Michele; Davis, Timothy A.; Gensior, Jindra; Liang, Fu-Heng; Lu, Anan; Williams, Thomas G.; Chung, Aeree
(ADS) / (arXiv)

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

2023-07-01T00:00:00+00:00

Abstract
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 central 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.

WISDOM project - XIV. SMBH mass in the early-type galaxies NGC 0612, NGC 1574, and NGC 4261 from CO dynamical modelling
Monthly Notices of the Royal Astronomical Society, 522, 4, 6170-6195
Ruffa, Ilaria; Davis, Timothy A.; Cappellari, Michele; Bureau, Martin ; Elford, Jacob; Iguchi, Satoru; Lelli, Federico; Liang, Fu-Heng ; Liu, Lijie; Lu, Anan; Sarzi, Marc ; Williams, Thomas G.
(ADS) / (arXiv)

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WISDOM Project - XIII. Feeding molecular gas to the supermassive black hole in the starburst AGN-host galaxy Fairall 49

2022-09-02T00:00:00+00:00

Abstract
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 (AGN): Fairall 49. We use new ALMA observations of the CO(2-1) line with a spatial resolution of about 80 pc together with ancillary HST imaging. We reach the following results: (1) The CO kinematics are well described by a regularly rotating gas disk 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) x 10^8 Msun, assuming that we have accurately subtracted the AGN and starburst light contributions, which have a luminosity of about 10^9 Lsun; (3) The SMBH mass agrees with the SMBH-stellar mass relation but is about 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-H_2 conversion factor (X_CO) for thermalised gas, suggesting low values of X_CO; (5) the molecular gas inflow rate increases steadily with radius and may be as high as 5 Msun/yr. This work highlights the potential of using high-resolution CO data to estimate, in addition to SMBH masses, the X_CO factor and gas inflow rates in nearby galaxies.

WISDOM Project - XIII. Feeding molecular gas to the supermassive black hole in the starburst AGN-host galaxy Fairall 49
Monthly Notices of the Royal Astronomical Society, 516, 3, 4066-4083
Lelli, Federico ; Davis, Timothy A. ; Bureau, Martin ; Cappellari, Michele ; Liu, Lijie ; Ruffa, Ilaria ; Smith, Mark D. ; Williams, Thomas G.
(ADS) / (arXiv)

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WISDOM Project - XII. Clump properties and turbulence regulated by clump-clump collisions in the dwarf galaxy NGC 404

2022-08-10T00:00:00+00:00

Abstract
We present a study of molecular structures (clumps and clouds) in the dwarf galaxy NGC 404 using high-resolution (0.86 × 0.51 pc²) Atacama Large Millimeter/sub-millimeter Array 12CO(2-1) observations. We find two distinct regions in NGC 404: a gravitationally stable central region (Toomre parameter Q = 3-30) and a gravitationally unstable molecular ring (Q ≲ 1). The molecular structures in the central region have a steeper size-linewidth relation and larger virial parameters than those in the molecular ring, suggesting gas is more turbulent in the former. In the molecular ring, clumps exhibit a shallower mass-size relation and larger virial parameters than clouds, implying density structures and dynamics are regulated by different physical mechanisms at different spatial scales. We construct an analytical model of clump-clump collisions to explain the results in the molecular ring. We propose that clump-clump collisions are driven by gravitational instabilities coupled with galactic shear, which lead to a population of clumps whose accumulation lengths (i.e. average separations) are approximately equal to their tidal radii. Our model-predicted clump masses and sizes (and mass-size relation) and turbulence energy injection rates (and size-linewidth relation) match the observations in the molecular ring very well, suggesting clump-clump collisions are the main mechanism regulating clump properties and gas turbulence in that region. As expected, our collision model does not apply to the central region, where turbulence is likely driven by clump migration.

WISDOM Project - XII. Clump properties and turbulence regulated by clump-clump collisions in the dwarf galaxy NGC 404
Monthly Notices of the Royal Astronomical Society, Volume 517, Issue 1, pp.632-656
Liu, Lijie; Bureau, Martin ; Li, Guang-Xing; Davis, Timothy A.; Nguyen, Dieu D.; Liang, Fu-Heng; Choi, Woorak ; Smith, Mark R.; Iguchi, Satoru
(ADS) / (arXiv)

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WISDOM project - XI. Star formation efficiency in the bulge of the AGN-host Galaxy NGC 3169 with SITELLE and ALMA

2022-06-07T00:00:00+00:00

Abstract
The star formation efficiency (SFE) has been shown to vary across different environments, particularly within galactic starbursts and deep within the bulges of galaxies. Various quenching mechanisms may be responsible, ranging from galactic dynamics to feedback from active galactic nuclei (AGNs). Here, we use spatially resolved observations of warm ionized gas emission lines (Hβ, [O III] λλ4959,5007, [N II] λλ6548,6583, Hα and [S II] λλ6716,6731) from the imaging Fourier transform spectrograph SITELLE at the Canada-France-Hawaii Telescope (CFHT) and cold molecular gas (12CO(2-1)) from the Atacama Large Millimeter/sub-millimeter Array (ALMA) to study the SFE in the bulge of the AGN-host galaxy NGC 3169. After distinguishing star-forming regions from AGN-ionized regions using emission-line ratio diagnostics, we measure spatially resolved molecular gas depletion times (Tdep ≡1/SFE) with a spatial resolution of ≍100 pc within a galactocentric radius of 1.8 kpc. We identify a star-forming ring located at radii 1.25 ± 0.6 kpc with an average τdep of 0.3 Gyr. At radii <0.9 kpc, however, the molecular gas surface densities and depletion times increase with decreasing radius, the latter reaching approximately 2.3 Gyr at a radius ≍500 pc. Based on analyses of the gas kinematics and comparisons with simulations, we identify AGN feedback, bulge morphology and dynamics as the possible causes of the radial profile of SFE observed in the central region of NGC 3169.

WISDOM project - XI. Star formation efficiency in the bulge of the AGN-host Galaxy NGC 3169 with SITELLE and ALMA
Monthly Notices of the Royal Astronomical Society, 2020, 514, 5035.
Lu, Anan; Boyce, Hope; Haggard, Daryl; Bureau, Martin; Liang, Fu-Heng; Liu, Lijie; Choi, Woorak; Cappellari, Michele; Chemin, Laurent; Chevance, Mélanie; Davis, Timothy A.; Drissen, Laurent; Elford, Jacob S.; Gensior, Jindra; Kruijssen, J. M. Diederik; Martin, Thomas; Massé, Etienne ; Robert, Carmelle; Ruffa, Ilaria; Rousseau-Nepton, Laurie; Sarzi, Marc; Savard, Gabriel ; Williams, Thomas G.
(ADS) / (arXiv)

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WISDOM Project – X. The morphology of the molecular ISM in galaxy centres and its dependence on galaxy structure

2022-03-04T00:00:00+00:00

Abstract
We use high-resolution maps of the molecular interstellar medium (ISM) in the centres of eighty-six nearby galaxies from the millimetre-Wave Interferometric Survey of Dark Object Masses (WISDOM) and Physics at High Angular Resolution in Nearby GalaxieS (PHANGS) surveys to investigate the physical mechanisms setting the morphology of the ISM at molecular cloud scales. We show that early-type galaxies tend to have smooth, regular molecular gas morphologies, while the ISM in spiral galaxy bulges is much more asymmetric and clumpy when observed at the same spatial scales. We quantify these differences using non-parametric morphology measures (Asymmetry, Smoothness and Gini), and compare these measurements with those extracted from idealised galaxy simulations. We show that the morphology of the molecular ISM changes systematically as a function of various large-scale galaxy parameters, including galaxy morphological type, stellar mass, stellar velocity dispersion, effective stellar mass surface density, molecular gas surface density, star formation efficiency and the presence of a bar. We perform a statistical analysis to determine which of these correlated parameters best predicts the morphology of the ISM. We find the effective stellar mass surface (or volume) density to be the strongest predictor of the morphology of the molecular gas, while star formation and bars maybe be important secondary drivers. We find that gas self-gravity is not the dominant process shaping the morphology of the molecular gas in galaxy centres. Instead effects caused by the depth of the potential well such as shear, suppression of stellar spiral density waves and/or inflow affect the ability of the gas to fragment.

WISDOM Project – X. The morphology of the molecular ISM in galaxy centres and its dependence on galaxy structure
Monthly Notices of the Royal Astronomical Society, 2022, Volume 512, Issue 1, pp.1522-1540
Davis, Timothy A. ; Gensior, Jindra ; Bureau, Martin ; Cappellari, Michele ; Choi, Woorak ; Elford, Jacob S. ; Kruijssen, J. M. Diederik ; Lelli, Federico ; Liang, Fu-Heng ; Liu, Lijie ; Ruffa, Ilaria ; Saito, Toshiki ; Sarzi, Marc ; Schruba, Andreas ; Williams, Thomas G.
(ADS) / (arXiv)

Integrated intensity maps of the molecular ISM in WISDOM and PHANGS galaxies, plotted as a function of their stellar-mass surface density and Gini parameter. Massive, bulge dominated galaxies have smoother ISM morphologies, even when observed at the same spatial resolution.

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WISDOM Project - IX. Giant molecular clouds in the lenticular galaxy NGC 4429: effects of shear and tidal forces on clouds

2021-06-21T00:00:00+00:00

Abstract
We present high spatial resolution (≍12 pc) Atacama Large Millimeter/submillimeter Array ¹²CO(J = 3-2) observations of the nearby lenticular galaxy NGC 4429. We identify 217 giant molecular clouds within the 450 pc radius molecular gas disc. The clouds generally have smaller sizes and masses but higher surface densities and observed linewidths than those of Milky Way disc clouds. An unusually steep size-linewidth relation (~ R_c^0.8) and large cloud internal velocity gradients (0.05-0.91 km s^-1 pc^-1) and observed virial parameters (<α_obs,vir> ≍ 4.0) are found, which appear due to internal rotation driven by the background galactic gravitational potential. Removing this rotation, an internal virial equilibrium appears to be established between the self-gravitational (U_sg) and turbulent kinetic (E_turb) energies of each cloud, i.e. $\langle \alpha {\rm sg,vir}\equiv \frac{2E{\rm turb}}{\vert U_{\rm sg}\vert }\rangle \approx 1.3$. However, to properly account for both self and external gravity (shear and tidal forces), we formulate a modified virial theorem and define an effective virial parameter $\alpha {\rm eff,vir}\equiv \alpha _{\rm sg,vir}+\frac{E{\rm ext}}{\vert U_{\rm sg}\vert }$ (and associated effective velocity dispersion). The NGC 4429 clouds then appear to be in a critical state in which the self-gravitational energy and the contribution of external gravity to the cloud’s energy budget (E_ext) are approximately equal, i.e. $\frac{E_{\rm ext}}{\vert U_{\rm sg}\vert }\approx 1$. As such, <α_eff,vir> ≍ 2.2 and most clouds are not virialized but remain marginally gravitationally bound. We show this is consistent with the clouds having sizes similar to their tidal radii and being generally radially elongated. External gravity is thus as important as self-gravity to regulate the clouds of NGC 4429.

WISDOM Project - IX. Giant molecular clouds in the lenticular galaxy NGC 4429: effects of shear and tidal forces on clouds
Monthly Notices of the Royal Astronomical Society, 2021, 505, 3, 4048.
Liu, L., Bureau, M., Blitz, L., Davis, T. A., Onishi, K., Smith, M., North, E., & Iguchi, S.
(ADS) / (arXiv)

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