Meridional tilt of the stellar velocity ellipsoid during bar buckling instability

Abstract

The structure and evolution of the stellar velocity ellipsoid plays an important role in shaping galaxies undergoing bar driven secular evolution and the eventual formation of a boxy/peanut bulge such as present in the Milky Way. Using collisionless N-body simulations, we show that during the formation of such a boxy/peanut bulge, the meridional shear stress of stars, which can be measured by the meridional tilt of the velocity ellipsoid, reaches a characteristic peak in its time evolution. It is shown that the onset of a bar buckling instability is closely connected to the maximum meridional tilt of the stellar velocity ellipsoid. Our findings bring new insight to this complex gravitational instability of the bar which complements the buckling instability studies based on orbital models. We briefly discuss the observed diagnostics of the stellar velocity ellipsoid during such a phenomenon.

10 pages, 16 Figures, accepted by the ApJ

References in corpus (5)

• The Radial Velocity Experiment (RAVE): second data release
• Estimation of the Tilt of the Stellar Velocity Ellipsoid from RAVE and Implications for Mass Models
• Initial conditions for disc galaxies
• Thick disk kinematics from RAVE and the solar motion
• Shape and orientation of stellar velocity ellipsoids in spiral galaxies

Cited by in corpus (25)

• The Dependence of Bar Frequency on Galaxy Mass, Colour, and Gas Content -- and Angular Resolution -- in the Local Universe
• Spinning dark matter halos promote bar formation
• Adventures of a tidally induced bar
• The Frequency and Stellar-Mass Dependence of Boxy/Peanut-Shaped Bulges in Barred Galaxies
• Boxy/peanut/X bulges, barlenses and the thick part of galactic bars: What are they and how did they form?
• Revealing the cosmic evolution of boxy/peanut-shaped bulges from HST COSMOS and SDSS
• Caught in the Act: Direct Detection of Galactic Bars in the Buckling Phase
• Box/peanut-shaped bulges in action space
• What determines the flatness of X-shaped structures in edge-on galaxies
• Evolution induced by dry minor mergers onto fast-rotator S0 galaxies
• Establishing the level of cylindrical rotation in Boxy/Peanut bulges
• Violent Buckling Benefits Galactic Bars
• The Tilt of the Local Velocity Ellipsoid as Seen by Gaia
• The velocity ellipsoid in the Galactic disc using Gaia DR1
• Revisiting the Stellar Velocity Ellipsoid - Hubble type relation: observations versus simulations
• Is the late buckling stage inevitable in the bar life?
• Building the peanut: simulations and observations of peanut-shaped structures and ansae in face-on disk galaxies
• Buckling bars in nearly face-on galaxies observed with MaNGA
• Bars and boxy/peanut bulges in thin and thick discs III. Boxy/peanut bulge formation and evolution in presence of thick discs
• Testing for relics of past strong buckling events in edge-on galaxies: Simulation predictions and data from S${}^4$G
• The tilt of the velocity ellipsoid of different Galactic disk populations
• The vertex coordinates of the Galaxy's stellar systems according to the Gaia DR3 catalogue
• Spatial orientation and shape of the velocity ellipsoids of the Gaia DR3 giants and subgiants in the Galactic plane
• Age distribution of stars in boxy/peanut/X-shaped bulges formed without bar buckling
• Bar Evolution in Edge-on Galaxies: A Demographic Study of Boxy/Peanut Bulges