Stellar Bars in Spinning Halos: Delayed Buckling and Absence of Slowdown

Abstract

We use high resolution numerical simulations in order to analyze the stellar bar evolution in spinning dark matter (DM) halos. Previous works have shown that the halo spin has a substantial effect on the bar evolution and can lead to bar dissolution following the vertical buckling instability. Here, we invoke the DM spin sequence, $\lambda =0-0.09$, and study the effect of DM density along this $\lambda$-sequence by varying the compactness of DM halo. We find that (1) varying the DM density has a profound effect on the stellar bar evolution along the $\lambda$-sequence, namely, on its amplitude, pattern speed, buckling time, etc.; (2) For $\lambda \gtrsim 0.04$, the buckling instability has been delayed progressively, and does not occur when the bar has reached its maximal strength; (3) Instead, stellar bars remain near maximal strength, and their amplitude plateau stage extends over $\sim 1-7$ Gyr, terminating with the buckling instability; (4) Although stellar bars remain strong during the plateau, their pattern speed stays nearly constant. The reason for this unusual behavior of stellar bars follows from the highly reduced gravitational torques which they experience due to the DM bar being aligned with the stellar bar. The performed orbital analysis shows that the delayed buckling results from a slow evolution of stellar oscillations along the bar major and vertical axes -- thus postponing the action of the vertical 2:1 resonance which pumps the rotational energy into vertical motions; (5) Peanut/boxy shaped bulges form at the beginning of the plateau and grow with time; (6) Strong stellar bars in spinning halos can avoid fast braking, resolving the long standing discrepancy between observations and $N$-body simulations. This behavior of stellar bars along the $\lambda$- and DM density-sequences, reveals a wealth of stellar bar properties which require additional study.

arXiv comment15 pages, 17 figures, to be published in MNRAS

References in corpus (40)

• The Structure of Cold Dark Matter Halos
• The cosmological simulation code GADGET-2
• GIZMO: A New Class of Accurate, Mesh-Free Hydrodynamic Simulation Methods
• A universal angular momentum profile for galactic halos
• What determines the strength and the slowdown rate of bars ?
• Constraints from Dynamical Friction on the Dark Matter Content of Barred Galaxies
• The Secular Evolution of Disk Structural Parameters
• Evolution of Stellar Bars in Live Axisymmetric Halos: Recurrent Buckling and Secular Growth
• Bar-Halo Interaction and Bar Growth
• Gas Feedback on Stellar Bar Evolution
• Is the dark-matter halo spin a predictor of galaxy spin and size?
• Anatomy of the Bar Instability in Cuspy Dark Matter Halos
• Gas-driven evolution of stellar orbits in barred galaxies
• The Cosmic Ballet: spin and shape alignments of haloes in the cosmic web
• Why Buckling Stellar Bars Weaken in Disk Galaxies
• Dark Matter Halos and Evolution of Bars in Disk Galaxies: Varying Gas Fraction and Gas Spatial Resolution
• A Fast Bar in the Post-Interaction Galaxy NGC 1023
• Spinning dark matter halos promote bar formation
• SDSS-IV MaNGA: pattern speeds of barred galaxies
• Revisiting the tension between fast bars and the $\Lambda$CDM paradigm
• An Iterative Method for Constructing Equilibrium Phase Models of Stellar Systems
• Three Mechanisms for Bar Thickening
• The dynamics of stellar disks in live dark-matter halos
• Dynamical Effects of Nuclear Rings in Disk Galaxies
• Secular Damping of Stellar Bars in Spinning Dark Matter Halos
• What Makes the Family of Barred Disc Galaxies So Rich: Damping Stellar Bars in Spinning Haloes
• Growing Live Disks Within Cosmologically Assembling Asymmetric Halos: Washing Out the Halo Prolateness
• Dark Matter Halos and Evolution of Bars in Disk Galaxies: Collisionless Models Revisited
• A bar in the inner halo of barred galaxies I. Structure and kinematics of a representative model
• SDSS-IV MaNGA: Bar pattern speed estimates with the Tremaine-Weinberg method and their error sources
• Dark Matter Trapping by Stellar Bars: The Shadow Bar
• Using Torque to Understand Barred Galaxy Models
• Modeling Evolution of Galactic Bars at Cosmic Dawn
• Using Commensurabilities and Orbit Structure to Understand Barred Galaxy Evolution
• Dark Matter Bars in Spinning Halos
• Stellar Bars in Counter-Rotating Dark Matter Halos: The Role of Halo Orbit Reversals
• A first estimate of the Milky Way dark matter halo spin
• The Origin of Buckling Instability in Galactic Bars: Searching for the Scapegoat
• An Iterative Method for the Construction of Equilibrium N-Body Models for Stellar Disks
• On Bars, Haloes, their Interaction and their Orbital Structure

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