arXiv subjects

Sabine Thater

Publications and source records attributed to Sabine Thater.

54 records · Page 3Linked to original sources

arXiv2023

The MAGPI Survey: Effects of Spiral Arms on Different Tracers of the Interstellar Medium and Stellar Populations at z~0.3

Spiral structures are important drivers of the secular evolution of disc galaxies, however, the origin of spiral arms and their effects on the development of galaxies remain mysterious. In this work, we present two three-armed spiral galaxies at z~0.3 in the Middle Age Galaxy Properties with Integral Field Spectroscopy (MAGPI) survey. Taking advantage of the high spatial resolution (~0.6'') of the Multi-Unit Spectroscopic Unit (MUSE), we investigate the two-dimensional distributions of different spectral parameters: Halpha, gas-phase metallicity, and D4000. We notice significant offsets in Halpha (~0.2 dex) as well as gas-phase metallicities (~0.05 dex) among the spiral arms, downstream and upstream of MAGPI1202197197 (SG1202). This observational signature suggests the spiral structure in SG1202 is consistent with arising from density wave theory. No azimuthal variation in Halpha or gas-phase metallicities is observed in MAGPI1204198199 (SG1204), which can be attributed to the tighter spiral arms in SG1204 than SG1202, coming with stronger mixing effects in the disc. The absence of azimuthal D4000 variation in both galaxies suggests the stars at different ages are well-mixed between the spiral arms and distributed around the disc regions. The different azimuthal distributions in Halpha and D4000 highlight the importance of time scales traced by various spectral parameters when studying 2D distributions in spiral galaxies. This work demonstrates the feasibility of constraining spiral structures by tracing interstellar medium (ISM) and stellar population at z~0.3, with a plan to expand the study to the full MAGPI survey.

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arXiv2023

Total mass slopes and enclosed mass constrained by globular cluster system dynamics

The goal of this work is to probe the total mass distribution of early-type galaxies with globular clusters (GCs) as kinematic tracers, by constraining the parameters of the profile with a flexible modelling approach. To that end, we leverage the extended spatial distribution of GCs from the SLUGGS survey ($\langle R_{\rm GC,\ max} \rangle \sim 8R_{\rm e}$) in combination with discrete dynamical modelling. We use discrete Jeans anisotropic modelling in cylindrical coordinates to determine the velocity moments at the location of the GCs in our sample. We use a Bayesian framework to determine the best-fit parameters of the total mass density profile and orbital properties of the GC systems. We find that the orbital properties (anisotropy and rotation of the dispersion-dominated GC systems) minimally impact the measurements of the inner slope and enclosed mass, while a strong presence of dynamically-distinct subpopulations or low numbers of kinematic tracers can bias the results. Owing to the large spatial extent of the tracers our method is sensitive to the intrinsic inner slope of the total mass profile and we find $\overlineα = -1.88\pm 0.01$ for 12 galaxies with robust measurements. To compare our results with literature values we fit a single power-law profile to the resulting total mass density. In the radial range 0.1-4~$R_{\rm e}$ our measured slope has a value of $\langle γ_{\rm tot}\rangle = -2.22\pm0.14$ and is in good agreement with the literature.

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arXiv2023

The distribution of stellar orbits in Eagle galaxies -- the effect of mergers, gas accretion, and secular evolution

The merger history of a galaxy is thought to be one of the major factors determining its internal dynamics, with galaxies having undergone different types or mergers (e.g. dry, minor or major mergers) predicted to show different dynamical properties. We study the instantaneous orbital distribution of galaxies in the Eagle simulation, colouring the orbits of the stellar particles by their stellar age, in order to understand whether stars form in particular orbits (e.g. in a thin or thick disc). We first show that Eagle reproduces well the observed stellar mass fractions in different stellar orbital families as a function of stellar mass and spin parameter at z = 0. We find that the youngest stars reside in a thin disc component that can extend to the very inner regions of galaxies, and that older stars have warmer orbits, with the oldest ones showing orbits consistent with both hot and counter-rotating classifications, which is consistent with the trend found in the Milky-Way and other disc galaxies. We also show that counter-rotating orbits trace galaxy mergers - in particular dry mergers, and that in the absence of mergers, counter-rotating orbits can also be born from highly misaligned gas accretion that leads to star formation.

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arXiv2023

Dynamical modelling of ATLAS$^{\rm 3D}$ galaxies

Triaxial dynamical models of massive galaxies observed in the ATLAS3D project can provide new insights into the complex evolutionary processes that shape galaxies. The ATLAS3D survey is ideal as the sample comprises a good mix of fast and slow rotators with vastly different mass assembly histories. We present a detailed dynamical study with our triaxial modelling code DYNAMITE, which models galaxies as a superposition of their stellar orbits. The models allow us to constrain the intrinsic shape of the stellar component, the distributions of the visible and invisible matter and the orbit distribution in these nearby early-type galaxies and to relate it with different evolutionary scenarios. Triaxial modelling is essential for these galaxies to understand their complex kinematical features.

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arXiv2023

Effect of the initial mass function on the dynamical SMBH mass estimate in the nucleated early-type galaxy FCC 47

Supermassive black holes (SMBHs) and nuclear star clusters (NSCs) co-exist in many galaxies. While the formation history of the black hole is essentially lost, NSCs preserve their evolutionary history imprinted onto their stellar populations and kinematics. Studying SMBHs and NSCs in tandem might help us to ultimately reveal the build-up of galaxy centres. In this study, we combine large-scale VLT/MUSE and high-resolution adaptive-optics-assisted VLT/SINFONI observations of the early-type galaxy FCC 47 with the goal being to assess the effect of a spatially (non-)variable initial mass function (IMF) on the determination of the mass of the putative SMBH in this galaxy. We achieve this by performing DYNAMITE Schwarzschild orbit-superposition modelling of the galaxy and its NSC. In order to properly take account of the stellar mass contribution to the galaxy potential, we create mass maps using a varying stellar mass-to-light ratio derived from single stellar population models with fixed and with spatially varying IMFs. Using the two mass maps, we estimate black hole masses of $(7.1^{+0.8}_{-1.1})\times 10^7\,M_{\odot}$ and $(4.4^{+1.2}_{-2.1}) \times 10^7\,M_{\odot}$ at $3σ$ signifance, respectively. Compared to models with constant stellar-mass-to-light ratio, the black hole masses decrease by 15% and 48%, respectively. Therefore, a varying IMF, both in its functional form and spatially across the galaxy, has a non-negligible effect on the SMBH mass estimate. Furthermore, we find that the SMBH in FCC 47 has probably not grown over-massive compared to its very over-massive NSC.

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arXiv2023

Evolution in the orbital structure of quiescent galaxies from MAGPI, LEGA-C and SAMI surveys: direct evidence for merger-driven growth over the last 7 Gy

We present the first study of spatially integrated higher-order stellar kinematics over cosmic time. We use deep rest-frame optical spectroscopy of quiescent galaxies at redshifts z=0.05, 0.3 and 0.8 from the SAMI, MAGPI and LEGA-C surveys to measure the excess kurtosis $h_4$ of the stellar velocity distribution, the latter parametrised as a Gauss-Hermite series. Conservatively using a redshift-independent cut in stellar mass ($M_\star = 10^{11}\,{\rm M}_\odot$), and matching the stellar-mass distributions of our samples, we find 7 $σ$ evidence of $h_4$ increasing with cosmic time, from a median value of 0.019$\pm$0.002 at z=0.8 to 0.059$\pm$0.004 at z=0.06. Alternatively, we use a physically motivated sample selection, based on the mass distribution of the progenitors of local quiescent galaxies as inferred from numerical simulations; in this case, we find 10 $σ$ evidence. This evolution suggests that, over the last 7 Gyr, there has been a gradual decrease in the rotation-to-dispersion ratio and an increase in the radial anisotropy of the stellar velocity distribution, qualitatively consistent with accretion of gas-poor satellites. These findings demonstrate that massive galaxies continue to accrete mass and increase their dispersion support after becoming quiescent.

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arXiv2023

Different higher-order kinematics between star-forming and quiescent galaxies based on the SAMI, MAGPI and LEGA-C surveys

We present the first statistical study of spatially integrated non-Gaussian stellar kinematics spanning 7 Gyr in cosmic time. We use deep, rest-frame optical spectroscopy of massive galaxies (stellar mass $M_\star > 10^{10.5} {\rm M}_\odot$) at redshifts z = 0.05, 0.3 and 0.8 from the SAMI, MAGPI and LEGA-C surveys, to measure the excess kurtosis $h_4$ of the stellar velocity distribution, the latter parametrised as a Gauss-Hermite series. We find that at all redshifts where we have large enough samples, $h_4$ anti-correlates with the ratio between rotation and dispersion, highlighting the physical connection between these two kinematic observables. In addition, and independently from the anti-correlation with rotation-to-dispersion ratio, we also find a correlation between $h_4$ and $M_\star$, potentially connected to the assembly history of galaxies. In contrast, after controlling for mass, we find no evidence of independent correlation between $h_4$ and aperture velocity dispersion or galaxy size. These results hold for both star-forming and quiescent galaxies. For quiescent galaxies, $h_4$ also correlates with projected shape, even after controlling for the rotation-to-dispersion ratio. At any given redshift, star-forming galaxies have lower $h_4$ compared to quiescent galaxies, highlighting the link between kinematic structure and star-forming activity.

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arXiv2022

Gas inflows in the polar ring of NGC 4111: the birth of an AGN

We have used Hubble Space Telescope (HST) images, SAURON Integral Field Spectroscopy (IFS) and adaptative optics assisted Gemini NIFS near-infrared K-band IFS to map the stellar and gas distribution, excitation and kinematics of the inner few kpc of the nearby edge-on S0 galaxy NGC 4111. The HST images map its $\approx$ 450 pc diameter dusty polar ring, with an estimated gas mass $\ge10^7$ M$_\odot$. The NIFS datacube maps the inner 110 pc radius at $\approx$ 7 pc spatial resolution revealing a $\approx$ 220 pc diameter polar ring in hot ($2267\pm166$ K) molecular H$_2$ 1-0 S(1) gas embedded in the polar ring. The stellar velocity field shows disk-dominated kinematics along the galaxy plane both in the SAURON large-scale and in the NIFS nuclear-scale data. The large-scale [O III] $\lambda5007$ Åvelocity field shows a superposition of two disk kinematics: one similar to that of the stars and another along the polar ring, showing non-circular motions that seem to connect with the velocity field of the nuclear H$_2$ ring, whose kinematics indicate accelerated inflow to the nucleus. The estimated mass inflow rate is enough not only to feed an Active Galactic Nucleus (AGN) but also to trigger circumnuclear star formation in the near future. We propose a scenario in which gas from the polar ring, which probably originated from the capture of a dwarf galaxy, is moving inwards and triggering an AGN, as supported by the local X-ray emission, which seems to be the source of the H$_2$ 1-0 S(1) excitation. The fact that we see neither near-UV nor Br$γ$ emission suggests that the nascent AGN is still deeply buried under the optically thick dust of the polar ring.

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arXiv2022

On the robustness of triaxial Schwarzschild modelling: The effects of correcting the orbit mirroring

In the past 15 years, the triaxial Schwarzschild orbit-superposition code by van den Bosch et al. (2008) has been widely applied to study the dynamics of galaxies. Recently, Quenneville et al. (2022) reported a bug 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 DYNAMITE, which is the publicly-released successor of the triaxial Schwarzschild code by van den Bosch et al. (2008). 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 a Schwarzschild triaxial code, 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 van den Bosch et al. (2008) triaxial Schwarzschild code are not significantly affected by the incorrect mirroring.

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arXiv2022

The SAMI Galaxy Survey: The internal orbital structure and mass distribution of passive galaxies from triaxial orbit-superposition Schwarzschild models

Dynamical models are crucial for uncovering the internal dynamics of galaxies, however, most of the results to date assume axisymmetry, which is not representative for a significant fraction of massive galaxies. Here, we build triaxial Schwarschild 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 $10^{9.5}$ to $10^{12} M_{\odot}$. We find that the changes in internal structures within 1$R_{\rm e}$ are correlated with the total stellar mass of the individual galaxies. The majority of the galaxies in the sample ($73\% \pm 3\%$) are oblate, while $19\% \pm 3\%$ are mildly triaxial and $8\% \pm 2\%$ have triaxial/prolate shape. Galaxies with $\log M_{\star}/M_{\odot} > 10.50$ are more likely to be non-oblate. We find a mean dark matter fraction of $f_{\rm{DM}} = 0.28 \pm 0.20$, within 1$R_{\rm e}$. Galaxies with higher intrinsic ellipticity (flatter) are found to have more negative velocity anisotropy $β_r$ (tangential anisotropy). $β_r$ also shows an anti-correlation with the edge-on spin parameter \lam, so that $β_r$ decreases with increasing \lam. 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.

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arXiv2021

Cross-checking SMBH mass estimates in NGC 6958 -- I: Stellar dynamics from adaptive optics-assisted MUSE observations

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 0.6 arcsec 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 Msun at 3σsignificance 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 Msun and (8.6+0.8-0.8) \times 10^8 Msun at 3σconfidence 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.

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arXiv2021

The MBHBM$^{\star}$ Project -- II. Molecular Gas Kinematics in the Lenticular Galaxy NGC 3593 Reveal a Supermassive Black Hole

As part of the Measuring Black Holes in Below Milky Way-mass (M$^\star$) galaxies (MBHBM$^\star$) Project, we present a dynamical measurement of the supermassive black hole (SMBH) mass in the nearby lenticular galaxy NGC 3593, using cold molecular gas $^{12}$CO(2-1) emission observed at an angular resolution of $\approx0''.3$ ($\approx10$ pc) with the Atacama Large Millimeter/submillimeter Array (ALMA). Our ALMA observations reveal a circumnuclear molecular gas disc (CND) elongated along the galaxy major axis and rotating around the SMBH. Using dynamical modelling, the molecular gas kinematics allow us to infer a SMBH mass $M_{\rm BH}=2.40_{-1.05}^{+1.87}\times10^6$ M$_\odot$ (only statistical uncertainties at the $3σ$ level). We also detect a massive core of cold molecular gas (CMC) of mass $M_{\rm CMC}=(5.4\pm1.2)\times10^6$ M$_\odot$ and effective (half-mass) radius $r_{\rm CMC,e}=11.2\pm2.8$ pc, co-spatial with a nuclear star cluster (NSC) of mass $M_{\rm NSC}=(1.67\pm0.48)\times10^7$ M$_\odot$ and effective radius $r_{\rm NSC,e}=5.0\pm1.0$~pc (or $0''.15\pm0''.03$). The mass profiles of the CMC and NSC are well described by Sérsic functions with indices $1-1.4$. Our $M_{\rm BH}$ and $M_{\rm NSC}$ estimates for NGC 3593 agree well with the recently compiled $M_{\rm BH}$-$M_{\rm NSC}$ scaling relation. Although the $M_{\rm NSC}$ uncertainty is twice the inferred $M_{\rm BH}$, the rapid central rise of the rotation velocities of the CND (as the radius decreases) clearly suggests a SMBH. Indeed, our dynamical models show that even if $M_{\rm NSC}$ is at the upper end of its allowed range, the evidence for a black hole does not vanish, but remains with a lower limit of $M_{\rm BH}>3\times10^5$ M$_\odot$.

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arXiv2021

Black hole mass measurement using ALMA observations of [CI] and CO emissions in the Seyfert 1 galaxy NGC7469

We present a supermassive black hole (SMBH) mass measurement in the Seyfert 1 galaxy NGC7469 using Atacama Large Millimeter/submillimeter Array (ALMA) observations of the atomic-${\rm [CI]}$(1-0) and molecular-$^{12}$CO(1-0) emission lines at the spatial resolution of $\approx0.3$" (or $\approx$ 100 pc). These emissions reveal that NGC7469 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 $σ/V\approx0.35$ ($r\sim0.5$") and $\sim0.19$ ($r>0.5"$), 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 ${\rm [CI]}$(1-0) kinematics yields a $M_{\rm BH}=1.78^{+2.69}_{-1.10}\times10^7$M$_\odot$ and $M/L_{\rm F547M}=2.25^{+0.40}_{-0.43}$ (M$_\odot$/L$_\odot$). The model using the CO(1-0) kinematics also gives a consistent $M_{\rm BH}$ with a larger uncertainty, up to an order of magnitude, i.e.\ $M_{\rm BH}=1.60^{+11.52}_{-1.45}\times10^7$M$_\odot$. This newly dynamical $M_{\rm BH}$ is $\approx$ 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 $M_{\rm BH}$, we are able to constrain the specific RM dimensionless scaling factor of $f=7.2^{+4.2}_{-3.4}$ for the AGN BLR in NGC7469. The gas within the unresolved BLR thus has a Keplerian virial velocity component and the inclination of $i\approx11.0^\circ$$_{-2.5}^{+2.2}$, confirming its face-on orientation in a Seyfert 1 AGN by assuming a geometrically thin BLR model.

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arXiv2019

Testing the robustness of black hole mass measurements with ALMA and MUSE

We present our ongoing work of using two independent tracers to estimate the supermassive black hole mass in the nearby early-type galaxy NGC 6958; namely integrated stellar and molecular gas kinematics. We used data from the Atacama Large Millimeter/submillimeter Array (ALMA), and the adaptive-optics assisted Multi-Unit Spectroscopic Explorer (MUSE) and constructed state-of-the-art dynamical models. The different methods provide black hole masses of $(2.89\pm 2.05) \times 10^8M_{\odot}$ from stellar kinematics and $(1.35\pm 0.09) \times 10^8M_{\odot}$ from molecular gas kinematics which are consistent within their $3σ$ uncertainties. Compared to recent M$_{\rm BH}$ - $σ_{\rm e}$ scaling relations, we derive a slightly over-massive black hole. Our results also confirm previous findings that gas-based methods tend to provide lower black hole masses than stellar-based methods. More black hole mass measurements and an extensive analysis of the method-dependent systematics are needed in the future to understand this noticeable discrepancy.

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arXiv2019

Six new supermassive black hole mass determinations from adaptive-optics assisted SINFONI observations

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 (MBH) 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 (σe) 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 ATLAS3D 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 which are consistent with recent MBH-σe 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.

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arXiv2019

The MBHBM* Project -- I: Measurement of the Central Black Hole Mass in Dwarf Galaxy NGC 3504 Using Molecular Gas Kinematics

We present the first measurement of the mass of a supermassive black hole (SMBH) in the nearby double-barred spiral galaxy NGC 3504 as part of the Measuring Black Holes Below the Milky Way ($M_{\star}$) mass galaxies (MBHBM$_{\star}$) Project. Our analysis is based on Atacama Large Millimeter/submillimeter Array (ALMA) Cycle-5 observations of the ${\rm ^{12}CO(2-1)}$ emission line. NGC 3504 has a circumnuclear gas disk (CND), which has a relatively high-velocity dispersion of 30 \kms. Our dynamical models of the CND yield a \Mbh~of $M_{\rm BH}=1.02^{+0.18}_{-0.15}\times10^7$\Msun and a mass-to-light ratio in $H$-band of \ml$_{\rm H}=0.66^{+1.44}_{-0.65}$ (\Msun/\Lsun). This black hole (BH) mass is consistent with BH--galaxy scaling relations. We also detect a central deficiency in the ${\rm ^{12}CO(2-1)}$ integrated intensity map with a diameter of 2.7 pc at the putative position of the SMBH. However, this hole is filled by a dense gas tracer ${\rm CS(5-4)}$ that peaks at the galaxy center found in one of the three low-velocity-resolution continuum spectral correlators. The ${\rm CS(5-4)}$ line has the same kinematics with the ${\rm ^{12}CO(2-1)}$ line within the CND, suggesting that it is also an alternative transition for measuring the central \Mbh~in NGC 3504 probably more accurately than the current commonly used of ${\rm ^{12}CO(2-1)}$ due to its centralization.

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arXiv2018

A quartet of black holes and a missing duo: probing the low-end of the Mbh - sigma relation with the adaptive optics assisted integral-field spectroscopy

We present mass estimates of supermassive black holes in six nearby fast rotating early-type galaxies (NGC4339, NGC4434, NGC4474, NGC4551, NGC4578 and NGC4762) 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 ATLAS3D 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 1-2sigma confidence level, except for one galaxy for which the difference is just above the 3sigma level. Two black holes (NGC4339 and NGC4434) are amongst the largest outliers from the current black hole mass - velocity dispersion relation, with masses of $(4.3^{+4.8}_{-2.3})\times10^7$ and $(7.0^{+2.0}_{-2.8})\times10^7$ M$_\odot$, respectively ($3σ$ confidence level). The black holes in NGC4578 and NGC4762 lie on the scaling relation with masses of $(1.9^{+0.6}_{-1.4})\times10^7$ and $(2.3^{+0.9}_{-0.6})\times10^7$ M$_\odot$, respectively (3sigma confidence level). For two galaxies (NGC4474 and NGC4551) we are able to place upper limits on their black holes masses ($<7\times10^6$ and $<5\times10^6$ M$_\odot$, 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.

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arXiv2016

A low upper mass limit for the central black hole in the late-type galaxy NGC 4414

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 Multi-Object 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 methods 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 Mbh= 1.56 x 10^6 Msun(at 3 sigma level) which is at least 1 sigma below the recent Mbh-sigma_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 Mbh-sigma_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.

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