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

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 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$R_{\mathrm{e}}$ 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 $f_{\mathrm{DM}}=0.28\pm 0.20$, within 1$R_{\mathrm{e}}$. Galaxies with higher intrinsic ellipticity (flatter) are found to have more negative velocity anisotropy ${\beta }_r$ (tangential anisotropy). ${\beta }_r$ also shows an anti-correlation with the edge-on spin parameter \lam, so that ${\beta }_r$ 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 ($V/\sigma$ - $h_3$) 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.

40 pages. Accepted for publication in ApJ

References in corpus (50)

• Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory
• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• The SAURON project -- IX. A kinematic classification for early-type galaxies
• The SAURON project -- X. The orbital anisotropy of elliptical and lenticular galaxies: revisiting the (V/sigma,epsilon) diagram with integral-field stellar kinematics
• The SAMI Galaxy Survey: instrument specification and target selection
• Triaxial orbit based galaxy models with an application to the (apparent) decoupled core galaxy NGC 4365
• A Supermassive Black Hole in an Ultracompact Dwarf Galaxy
• The MASSIVE Survey - I. A Volume-Limited Integral-Field Spectroscopic Study of the Most Massive Early-Type Galaxies within 108 Mpc
• The SAURON project - XII. Kinematic substructures in early-type galaxies: evidence for disks in fast rotators
• Dynamical modelling of luminous and dark matter in 17 Coma early-type galaxies
• The SAMI Galaxy Survey: the link between angular momentum and optical morphology
• The SAMI Galaxy Survey: Revisiting Galaxy Classification Through High-Order Stellar Kinematics
• Stellar kinematics across the Hubble sequence in the CALIFA survey: General properties and aperture corrections
• The Atlas3D project - XXIV. The intrinsic shape distribution of early-type galaxies
• The SAMI Galaxy Survey: the third and final data release
• Orbital decomposition of CALIFA spiral galaxies
• The SAMI Galaxy Survey: Global stellar populations on the size-mass plane
• The stellar initial mass function of early type galaxies from low to high stellar velocity dispersion: homogeneous analysis of ATLAS${}^{3D}$ and Sloan Lens ACS galaxies
• The SAURON Project - XIV. No escape from V${}_{\mathrm{esc}}$: a global and local parameter in early-type galaxy evolution
• Triaxial orbit-based modelling of the Milky Way Nuclear Star Cluster
• The SAMI Galaxy Survey: Quenching of star formation in clusters I. Transition galaxies
• The SAMI Galaxy Survey: Revising the Fraction of Slow Rotators in IFS Galaxy Surveys
• Combining Stellar Populations with Orbit-Superposition Dynamical Modelling - the Formation History of the Lenticular Galaxy NGC 3115
• Systematic trends in total-mass profiles from dynamical models of early-type galaxies
• Recovery of the internal orbital structure of galaxies
• The CALIFA view on stellar angular momentum across the Hubble sequence
• The origin and properties of massive prolate galaxies in the Illustris simulation
• A new implementation of the Schwarzschild method for constructing observationally-driven dynamical models of galaxies of all morphological types
• Six new supermassive black hole mass determinations from adaptive-optics assisted SINFONI observations
• The SAMI Galaxy Survey: the intrinsic shape of kinematically selected galaxies
• The SAMI Galaxy Survey: stellar population and structural trends across the Fundamental Plane
• Evaluating the ability of triaxial Schwarzschild modelling to estimate properties of galaxies from the Illustris simulation
• Probing the kinematic morphology-density relation of early-type galaxies with MaNGA
• A novel approach to optimize the regularization and evaluation of dynamical models using a model selection framework
• The SAMI Galaxy Survey: Mass and Environment as Independent Drivers of Galaxy Dynamics
• Applying Schwarzschild's orbit superposition method to barred or non-barred disc galaxies
• A SAMI and MaNGA view on the stellar kinematics of galaxies on the star-forming main sequence
• The MASSIVE Survey -- XV. A Stellar Dynamical Mass Measurement of the Supermassive Black Hole in Massive Elliptical Galaxy NGC 1453
• Triaxial Orbit-based Dynamical Modeling of Galaxies with Supermassive Black Holes and an Application to Massive Elliptical Galaxy NGC 1453
• SDSS-IV MaNGA: Internal mass distributions and orbital structures of early-type galaxies and their dependence on environment
• A low upper mass limit for the central black hole in the late-type galaxy NGC 4414
• SMART: A new implementation of Schwarzschild's Orbit Superposition technique for triaxial galaxies and its application to an N-body merger simulation
• Intrinsic Axis Ratio Distribution of Early-type Galaxies From Sloan Digital Sky Survey
• Hector - a new massively multiplexed IFS instrument for the Anglo-Australian Telescope
• Non-parametric Triaxial Deprojection of Elliptical Galaxies
• Complexity on dwarf galaxies scale: A bimodal distribution function in Sculptor
• Dynamical modelling of the twisted galaxy PGC 046832
• The colors of bulges and disks in the core and outskirts of galaxy clusters
• Mild evolution of the stellar metallicity gradients of disc galaxies
• Larger ${\lambda }_R$ in the disc of isolated active spiral galaxies than in their non-active twins

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• The SAMI Galaxy Survey: Physical drivers of stellar-gas kinematic misalignments in the nearby Universe
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• On the robustness of triaxial Schwarzschild modelling: The effects of correcting the orbit mirroring
• The SAMI Galaxy Survey: Environmental analysis of the orbital structures of passive galaxies
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• On the kinematic nature of apparent discs at high redshifts: Local counterparts are not dominated by ordered rotation but by tangentially anisotropic random motion
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• Shapes of dark matter haloes with discrete globular cluster dynamics: The example of NGC 5128 (Centaurus A)
• Self-consistent dynamical models with a finite extent -- II. Radially truncated models
• The Three Hundred: The existence of massive dark matter-deficient satellite galaxies in cosmological simulations
• On the Origin of the Variety of Velocity Dispersion Profiles of Galaxies
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• Systematics in ETG Mass Profile Modelling: Strong Lensing & Stellar Dynamics
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• Dark matter in ALFALFA galaxies: Investigating galaxy-halo connection