ORCID Profile
0000-0003-1820-2041
Current Organisations
University of Vienna
,
Universität Wien
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Publisher: Oxford University Press (OUP)
Date: 21-08-2023
Publisher: EDP Sciences
Date: 19-12-2016
Publisher: American Astronomical Society
Date: 05-2022
Abstract: 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 s le consists of 161 passive galaxies with total stellar masses in the range 10 9.5 –10 12 M ⊙ . We find that the changes in internal structures within 1 R e are correlated with the total stellar mass of the in idual galaxies. The majority of the galaxies in the s le (73% ± 3%) are oblate, while 19% ± 3% are mildly triaxial and 8% ± 2% have triaxial rolate 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 1 R 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.
Publisher: EDP Sciences
Date: 05-2019
DOI: 10.1051/0004-6361/201834808
Abstract: 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 coevolution. We add six new black hole mass ( M BH ) measurements of nearby fast rotating early-type galaxies to the known black hole mass s le, 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 combined 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 built 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 3 σ 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.
Publisher: Oxford University Press (OUP)
Date: 21-08-2023
Publisher: Oxford University Press (OUP)
Date: 23-03-2018
DOI: 10.1093/MNRAS/STY778
Publisher: EDP Sciences
Date: 11-2022
DOI: 10.1051/0004-6361/202243926
Abstract: In the past 15 yr, 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.
No related grants have been discovered for Sabine Thater.