The SAMI Galaxy Survey: the intrinsic shape of kinematically selected galaxies

Abstract

Using the stellar kinematic maps and ancillary imaging data from the Sydney AAO Multi Integral field (SAMI) Galaxy Survey, the intrinsic shape of kinematically-selected samples of galaxies is inferred. We implement an efficient and optimised algorithm to fit the intrinsic shape of galaxies using an established method to simultaneously invert the distributions of apparent ellipticities and kinematic misalignments. The algorithm output compares favourably with previous studies of the intrinsic shape of galaxies based on imaging alone and our re-analysis of the ATLAS3D data. Our results indicate that most galaxies are oblate axisymmetric. We show empirically that the intrinsic shape of galaxies varies as a function of their rotational support as measured by the "spin" parameter proxy Lambda_Re. In particular, low spin systems have a higher occurrence of triaxiality, while high spin systems are more intrinsically flattened and axisymmetric. The intrinsic shape of galaxies is linked to their formation and merger histories. Galaxies with high spin values have intrinsic shapes consistent with dissipational minor mergers, while the intrinsic shape of low-spin systems is consistent with dissipationless multi-merger assembly histories. This range in assembly histories inferred from intrinsic shapes is broadly consistent with expectations from cosmological simulations.

arXiv comment15 pages, 11 figures, MNRAS in print

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Cited by in corpus (34)

• SDSS-IV MaNGA: Stellar angular momentum of about 2300 galaxies: unveiling the bimodality of massive galaxy properties
• The SAMI Galaxy Survey: the third and final data release
• The SAMI Galaxy Survey: comparing 3D spectroscopic observations with galaxies from cosmological hydrodynamical simulations
• The relationship between the morphology and kinematics of galaxies and its dependence on dark matter halo structure in EAGLE
• The Fornax3D project: overall goals, galaxy sample, MUSE data analysis and initial results
• The SAMI Galaxy Survey: Stellar and gas misalignments and the origin of gas in nearby galaxies
• A relation between characteristic stellar age of galaxies and their intrinsic shape
• The extended Planetary Nebula Spectrograph (ePN.S) early-type galaxy survey. The kinematic diversity of stellar halos and the relation between halo transition scale and stellar mass
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• The SAMI Galaxy Survey: The internal orbital structure and mass distribution of passive galaxies from triaxial orbit-superposition Schwarzschild models
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• The influence of Massive Black Hole Binaries on the Morphology of Merger Remnants
• SDSS-IV MaNGA: The intrinsic shape of slow rotator early-type galaxies
• The SAMI Galaxy Survey: Mass and Environment as Independent Drivers of Galaxy Dynamics
• How nucleation and luminosity shape faint dwarf galaxies
• A SAMI and MaNGA view on the stellar kinematics of galaxies on the star-forming main sequence
• Morphology and kinematics of orbital components in CALIFA galaxies across the Hubble sequence
• Triaxial Orbit-based Dynamical Modeling of Galaxies with Supermassive Black Holes and an Application to Massive Elliptical Galaxy NGC 1453
• Non-parametric Triaxial Deprojection of Elliptical Galaxies
• Prospects for Recovering Galaxy Intrinsic Shapes from Projected Quantities
• Merger histories of brightest group galaxies from MUSE stellar kinematics
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• The SAMI Galaxy Survey: The contribution of different kinematic classes to the stellar mass function of nearby galaxies
• The SAMI Galaxy Survey: embedded discs and radial trends in outer dynamical support across the Hubble sequence
• On the application of dimensionality reduction and clustering algorithms for the classification of kinematic morphologies of galaxies
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