We present a dynamical-mass measurement of the supermassive black hole (SMBH) in the nearby double-barred spiral galaxy NGC 3504 as part of the Measuring Black Holes in Below Milky Way (M ⋆) mass galaxies (MBHBM ⋆) Project. Our analysis is based on Atacama Large Millimeter/submillimeter Array (ALMA) Cycle-5 observations of the 12 CO(2 − 1) emission line. These observations probe NGC 3504's circumnuclear gas disk (CND). Our dynamical model of the CND simultaneously constrains a black hole (BH) mass of 1.6 +0.6 −0.4 × 10 7 M ⊙ , which is consistent with the empirical BH-galaxy scaling relations, and a mass-to-light ratio in H-band of 0.44 ± 0.12 (M ⊙ /L ⊙). This measurement also relies on our new distant estimation to the galaxy of 32.4 ± 2.1 Mpc using the surface brightness fluctuation method (SBF), which is much further than the existing distant estimates. Additionally, our observations detect a central deficit in the 12 CO(2 − 1) integrated intensity map with a diameter of 6.3 pc at the putative position of the SMBH. However, we find a dense gas tracer CS(5 − 4) peaks at the galaxy center, filling in the 12 CO(2 − 1)-attenuated hole. Holes like this one are observed in other galaxies, and our observations suggest these may be caused by changing excitation conditions rather than a true absence of molecular gas around the nucleus.
Different massive black hole mass -host galaxy scaling relations suggest that the growth of massive black holes is entangled with the evolution of their host galaxies. The number of measured black hole masses is still limited, and additional measurements are necessary to understand the underlying physics of this apparent co-evolution. We add six new black hole mass (M BH ) measurements of nearby fast rotating early-type galaxies to the known black hole mass sample, namely NGC 584, NGC 2784, NGC 3640, NGC 4570, NGC 4281 and NGC 7049. Our target galaxies have effective velocity dispersions (σ e ) between 170 and 245 km s −1 , and thus this work provides additional insight into the black hole properties of intermediate-mass early-type galaxies. We combine high-resolution adaptive-optics SINFONI data with large-scale MUSE, VIMOS and SAURON data from ATLAS 3D to derive two-dimensional stellar kinematics maps. We then build both Jeans Anisotropic Models and axisymmetric Schwarzschild models to measure the central black hole masses. Our Schwarzschild models provide black hole masses of (1.3 ± 0.5) × 10 8 M for NGC 584, (1.0 ± 0.6) × 10 8 M for NGC 2784, (7.7 ± 5) × 10 7 M for NGC 3640, (5.4 ± 0.8) × 10 8 M for NGC 4281, (6.8 ± 2.0) × 10 7 M for NGC 4570 and (3.2 ± 0.8) × 10 8 M for NGC 7049 at 3σ confidence level, which are consistent with recent M BH -σ e scaling relations. NGC 3640 has a velocity dispersion dip and NGC 7049 a constant velocity dispersion in the center, but we can clearly constrain their lower black hole mass limit. We conclude our analysis with a test on NGC 4570 taking into account a variable mass-to-light ratio (M/L) when constructing dynamical models. When considering M/L variations linked mostly to radial changes in the stellar metallicity, we find that the dynamically determined black hole mass from NGC 4570 decreases by 30%. Further investigations are needed in the future to account for the impact of radial M/L gradients on dynamical modeling.
We present mass estimates of supermassive black holes in six nearby fast rotating early-type galaxies (NGC 4339, NGC 4434, NGC 4474, NGC 4551, NGC 4578 and NGC 4762) with effective stellar velocity dispersion around 100 km/s. We use near-infrared laser-guide adaptive optics observations with the GEMINI/NIFS to derive stellar kinematics in the galactic nuclei, and SAURON observations from the ATLAS 3D Survey for large-scale kinematics. We build axisymmetric Jeans Anisotropic Models and axisymmetric Schwarzschild dynamical models. Both modelling approaches recover consistent orbital anisotropies and black hole masses within 1 − 2σ confidence level, except for one galaxy for which the difference is just above the 3σ level. Two black holes (NGC 4339 and NGC 4434) are amongst the largest outliers from the current black hole mass -velocity dispersion relation, with masses of (4.3 +4.8 −2.3 ) × 10 7 and (7.0 +2.0 −2.8 ) × 10 7 M , respectively (3σ confidence level). The black holes in NGC 4578 and NGC 4762 lie on the scaling relation with masses of (1.9 +0.6 −1.4 ) × 10 7 and (2.3 +0.9 −0.6 ) × 10 7 M , respectively (3σ confidence level). For two galaxies (NGC 4474 and NGC 4551) we are able to place upper limits on their black holes masses (< 7×10 6 and < 5×10 6 M , respectively, 3σ confidence level). The kinematics for these galaxies clearly indicate central velocity dispersion drops within a radius of 35 pc and 80 pc, respectively. These drops cannot be associated with cold stellar structures and our data do not have the resolution to exclude black holes with masses an order of magnitude smaller than the predictions. Parametrizing the orbital distribution in spherical coordinates, the vicinity of the black holes is characterized by isotropic or mildly tangential anisotropy.
We present our mass estimate of the central black hole in the isolated spiral galaxy NGC 4414. Using natural guide star adaptive optics assisted observations with the Gemini Near-Infrared Integral Field Spectrometer (NIFS) and the natural seeing Gemini MultiObject Spectrographs-North (GMOS), we derived two-dimensional stellar kinematic maps of NGC 4414 covering the central 1.5 arcsec and 10 arcsec, respectively, at a NIFS spatial resolution of 0.13 arcsec. The kinematic maps reveal a regular rotation pattern and a central velocity dispersion dip down to around 105 km/s. We constructed dynamical models using two different methods: Jeans anisotropic dynamical modeling and axisymmetric Schwarzschild modeling. Both modeling methods give consistent results, but we cannot constrain the lower mass limit and only measure an upper limit for the black hole mass of M BH = 1.56 × 10 6 M (at 3 σ level) which is at least 1σ below the recent M BH − σ e relations. Further tests with dark matter, mass-to-light ratio variation and different light models confirm that our results are not dominated by uncertainties. The derived upper limit mass is not only below the M BH − σ e relation, but is also five times lower than the lower limit black hole mass anticipated from the resolution limit of the sphere of influence. This proves that via high quality integral field data we are now able to push black hole measurements down to at least five times less than the resolution limit.
We present a supermassive black hole (SMBH) mass measurement in the Seyfert 1 galaxy NGC 7469 using Atacama Large Millimeter/submillimeter Array (ALMA) observations of the atomic-[CI](1-0) and molecular-12CO(1-0) emission lines at the spatial resolution of ≈0${_{.}^{\prime\prime}}$3 (or ≈ 100 pc). These emissions reveal that NGC 7469 hosts a circumnuclear gas disc (CND) with a ring-like structure and a two-arm/bi-symmetric spiral pattern within it, surrounded by a starbursting ring. The CND has a relatively low σgas/V ≈ 0.35 (r ≲ 0${_{.}^{\prime\prime}}$5) and ≈0.19 (r > 0${_{.}^{\prime\prime}}$5), suggesting that the gas is dynamically settled and suitable for dynamically deriving the mass of its central source. As is expected from X-ray dominated region (XDR) effects that dramatically increase an atomic carbon abundance by dissociating CO molecules, we suggest that the atomic [CI](1-0) emission is a better probe of SMBH masses than CO emission in AGNs. Our dynamical model using the [CI](1-0) kinematics yields a $M_{\rm BH}=1.78^{+2.69}_{-1.10}\times 10^7$ M⊙ and $M/L_{\rm F547M}=2.25^{+0.40}_{-0.43}$ (M⊙/L⊙). The model using the 12CO(1-0) kinematics also gives a consistent MBH with a larger uncertainty, up to an order of magnitude, i.e. $M_{\rm BH}=1.60^{+11.52}_{-1.45}\times 10^7$ M⊙. This newly dynamical MBH is ≈ 2 times higher than the mass determined from the reverberation mapped (RM) method using emissions arising in the unresolved broad-line region (BLR). Given this new MBH, we are able to constrain the specific RM dimensionless scaling factor of $f=7.2^{+4.2}_{-3.4}$ for the AGN BLR in NGC 7469. The gas within the unresolved BLR thus has a Keplerian virial velocity component and the inclination of i ≈ 11.0○$_{-2.5}^{+2.2}$, confirming its face-on orientation in a Seyfert 1 AGN by assuming a geometrically thin BLR model.
Supermassive black hole masses (MBH) can dynamically be estimated with various methods and using different kinematic tracers. Different methods have only been cross-checked for a small number of galaxies and often show discrepancies. To understand these discrepancies, detailed cross-comparisons of additional galaxies are needed. We present the first part of our cross-comparison between stellar- and gas-based MBH estimates in the nearby fast-rotating early-type galaxy NGC 6958. The measurements presented here are based on ground-layer adaptive optics-assisted Multi-Unit Spectroscopic Explorer (MUSE) science verification data at around 0${^{\prime\prime}_{.}}$6 spatial resolution. The spatial resolution is a key ingredient for the measurement and we provide a Gaussian parametrisation of the adaptive optics-assisted point spread function (PSF) for various wavelengths. From the MUSE data, we extracted the stellar kinematics and constructed dynamical models. Using an axisymmetric Schwarzschild technique, we measured an MBH of $(3.6^{+2.7}_{-2.4}) \times 10^8\,$M⊙ at 3σ significance taking kinematical and dynamical systematics (e.g. radially-varying mass-to-light ratio) into account. We also added a dark halo, but our data does not allow to constrain the dark matter fraction. Adding dark matter with an abundance matching prior results in a 25 per cent more massive black hole. Jeans anisotropic models return MBH of $(4.6^{+2.5}_{-2.7}) \times 10^8\, \mathrm{M}_{\odot }$ and $(8.6^{+0.8}_{-0.8}) \times 10^8\, \mathrm{M}_{\odot }$ at 3σ confidence for spherical and cylindrical alignment of the velocity ellipsoid, respectively. In a follow-up study, we will compare the stellar-based MBH with those from cold and warm gas tracers, which will provide additional constraints for the MBH for NGC 6958, and insights into assumptions that lead to potential systematic uncertainty.
Dynamical models are crucial for uncovering the internal dynamics of galaxies; however, most of the results to date assume axisymmetry, which is not representative of a significant fraction of massive galaxies. Here, we build triaxial Schwarzschild orbit-superposition models of galaxies taken from the SAMI Galaxy Survey, in order to reconstruct their inner orbital structure and mass distribution. The sample consists of 161 passive galaxies with total stellar masses in the range 109.5–1012 M ⊙. We find that the changes in internal structures within 1R e are correlated with the total stellar mass of the individual galaxies. The majority of the galaxies in the sample (73% ± 3%) are oblate, while 19% ± 3% are mildly triaxial and 8% ± 2% have triaxial/prolate shape. Galaxies with log M ⋆ / M ⊙ > 10.50 are more likely to be non-oblate. We find a mean dark matter fraction of f DM = 0.28 ± 0.20, within 1R e. Galaxies with higher intrinsic ellipticity (flatter) are found to have more negative velocity anisotropy β r (tangential anisotropy). β r also shows an anticorrelation with the edge-on spin parameter λ Re , EO , so that β r decreases with increasing λ Re , EO , reflecting the contribution from disk-like orbits in flat, fast-rotating galaxies. We see evidence of an increasing fraction of hot orbits with increasing stellar mass, while warm and cold orbits show a decreasing trend. We also find that galaxies with different (V/σ – h 3) kinematic signatures have distinct combinations of orbits. These results are in agreement with a formation scenario in which slow- and fast-rotating galaxies form through two main channels.
In the past 15 years, the triaxial Schwarzschild orbit-superposition code developed by van den Bosch and van de Ven in Leiden has been widely applied to study the dynamics of galaxies. Recently, a bug was reported in the orbit calculation of this code, specifically in the mirroring procedure that is used to speed up the computation. We have fixed the incorrect mirroring in the DYNAMITE code, which is the publicly-released successor of the Leiden triaxial Schwarzschild code. In this study, we provide a thorough quantification of how this bug has affected the results of dynamical analyses performed with this code. We compare results obtained with the original and corrected versions of DYNAMITE, and discuss the differences in the phase-space distribution of a single orbit and in the global stellar orbit distribution, in the mass estimate of the central black hole in the highly triaxial galaxy PGC 46832, and in the measurement of intrinsic shape and enclosed mass for more than 50 galaxies. Focusing on the typical scientific applications of the Schwarzschild method, in all our tests we find that differences are negligible with respect to the statistical and systematic uncertainties. We conclude that previous results with the Leiden triaxial Schwarzschild code are not significantly affected by the incorrect mirroring.
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