The SAMI Galaxy Survey: Physical drivers of stellar-gas kinematic misalignments in the nearby Universe

Abstract

Misalignments between the rotation axis of stars and gas are an indication of external processes shaping galaxies throughout their evolution. Using observations of 3068 galaxies from the SAMI Galaxy Survey, we compute global kinematic position angles for 1445 objects with reliable kinematics and identify 169 (12%) galaxies which show stellar-gas misalignments. Kinematically decoupled features are more prevalent in early-type/passive galaxies compared to late-type/star-forming systems. Star formation is the main source of gas ionisation in only 22% of misaligned galaxies; 17% are Seyfert objects, while 61% show Low-Ionisation Nuclear Emission-line Region features. We identify the most probable physical cause of the kinematic decoupling and find that, while accretion-driven cases are dominant, for up to 8% of our sample, the misalignment may be tracing outflowing gas. When considering only misalignments driven by accretion, the acquired gas is feeding active star formation in only $\sim$1/4 of cases. As a population, misaligned galaxies have higher Sérsic indices and lower stellar spin & specific star formation rates than appropriately matched samples of aligned systems. These results suggest that both morphology and star formation/gas content are significantly correlated with the prevalence and timescales of misalignments. Specifically, torques on misaligned gas discs are smaller for more centrally concentrated galaxies, while the newly accreted gas feels lower viscous drag forces in more gas-poor objects. Marginal evidence of star formation not being correlated with misalignment likelihood for late-type galaxies suggests that such morphologies in the nearby Universe might be the result of preferentially aligned accretion at higher redshifts.

25 pages (5 in appendices); 11 figures (2 in appendices); accepted for publication in MNRAS

References in corpus (41)

• The Host Galaxies and Classification of Active Galactic Nuclei
• Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory
• 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
• GALEX-SDSS-WISE Legacy Catalog (GSWLC): Star Formation Rates, Stellar Masses and Dust Attenuations of 700,000 Low-redshift Galaxies
• Galaxy And Mass Assembly (GAMA): Data Release 4 and the z < 0.1 total and z < 0.08 morphological galaxy stellar mass functions
• The Dawes Review 9: The role of cold gas stripping on the star formation quenching of satellite galaxies
• Star formation sustained by gas accretion
• The SAMI Galaxy Survey: the link between angular momentum and optical morphology
• The SAMI Galaxy Survey: Revisiting Galaxy Classification Through High-Order Stellar Kinematics
• The impact of feedback on cosmological gas accretion
• The SAMI Galaxy Survey: Early Data Release
• The SAMI Galaxy Survey: the third and final data release
• The SAMI Galaxy Survey: Spatially Resolving the Main Sequence of Star Formation
• The SAMI Galaxy Survey: Cubism and covariance, putting round pegs into square holes
• The Central Kiloparsec of Seyfert and Inactive Host Galaxies: a Comparison of Two-Dimensional Stellar and Gaseous Kinematics
• LZIFU: an emission-line fitting toolkit for integral field spectroscopy data
• Building disc structure and galaxy properties through angular momentum: The DARK SAGE semi-analytic model
• SDSS-IV MaNGA: Properties of galaxies with kinematically decoupled stellar and gaseous components
• xGASS: Gas-rich central galaxies in small groups and their connections to cosmic web gas feeding
• On the lifetime of merger features of equal-mass disk mergers
• The SAMI Galaxy Survey: Quenching of star formation in clusters I. Transition galaxies
• The SAMI Galaxy Survey: Data Release One with Emission-line Physics Value-Added Products
• The origin of the atomic and molecular gas contents of early-type galaxies. II. Misaligned gas accretion
• The Close AGN Reference Survey (CARS). A massive multi-phase outflow impacting the edge-on galaxy HE1353-1917
• Kinematic alignment of non-interacting CALIFA galaxies: Quantifying the impact of bars on stellar and ionised gas velocity field orientations
• Gas accretion from minor mergers in local spiral galaxies
• The growth of the central region by acquisition of counter-rotating gas in star-forming galaxies
• The SAMI Galaxy Survey: The internal orbital structure and mass distribution of passive galaxies from triaxial orbit-superposition Schwarzschild models
• The SAMI Galaxy Survey: stellar population and structural trends across the Fundamental Plane
• Recovering ${\lambda }_R$ and $V/\sigma$ from seeing-dominated IFS data
• The SAMI Galaxy Survey: a statistical approach to an optimal classification of stellar kinematics in galaxy surveys
• Simulations of AGN Driven Galactic Outflow Morphology and Content
• The SAMI Galaxy Survey: Mass and Environment as Independent Drivers of Galaxy Dynamics
• A SAMI and MaNGA view on the stellar kinematics of galaxies on the star-forming main sequence
• SDSS-IV MaNGA: Global Properties of Kinematically Misaligned Galaxies
• SDSS-IV MaNGA : spatial resolved properties of kinematically misaligned galaxies
• Star-Gas Misalignment in Galaxies: II. Origins Found from the Horizon-AGN Simulation
• Larger ${\lambda }_R$ in the disc of isolated active spiral galaxies than in their non-active twins
• Unraveling the complex structure of AGN-driven outflows: IV. Comparing AGNs with and without strong outflows

Cited by in corpus (11)

• WALLABY Pilot Survey: the Potential Polar Ring Galaxies NGC~4632 and NGC~6156
• The SAMI Galaxy Survey: Using Tidal Streams and Shells to Trace the Dynamical Evolution of Massive Galaxies
• The SAMI Galaxy Survey: galaxy spin is more strongly correlated with stellar population age than mass or environment
• The formation pathways of compact elliptical galaxies
• The Tully-Fisher relation from SDSS-MaNGA: Physical causes of scatter and variation at different radii
• MaNGA AGN dwarf galaxies (MAD) -- II. AGN outflows in dwarf galaxies
• Witnessing a Transformation to Blue-cored Dwarf Early-type Galaxies in Filaments and the Cluster Outskirts: Gas-phase Abundances and Internal Kinematics Perspectives
• The circular velocity and halo mass functions of galaxies in the nearby Universe
• Stellar-gas kinematic misalignments in EAGLE: lifetimes and longevity of misaligned galaxies
• The SAMI Survey: Evidence for dynamical coupling of ionised gas and young stellar populations
• Kinematic misalignment as a driver of black hole activity in galaxies with external interactions