Effects of Inner Halo Angular Momentum on the Peanut/X-shapes of Bars

Abstract

Cosmological simulations show that dark matter halos surrounding baryonic disks have a wide range of angular momenta, measured by the spin parameter ($\lambda$). In this study, we bring out the importance of inner angular momentum($<$30 kpc), measured in terms of the halo spin parameter, on the secular evolution of the bar using N-body simulations. We have varied the halo spin parameter $\lambda$ from 0 to 0.1 for co-rotating (prograde) spinning halos and one counter-rotating (retrograde) halo spin ($\lambda$=-0.1) with respect to the disk. We report that as the halo spin increases, the buckling is also triggered earlier and is followed by a second buckling phase in high-spin halo models. The timescale for the second buckling is significantly longer than the first buckling. We find that bar strength does not reduce significantly after the buckling in all of our models, which provides new insights about the role of inner halo angular momentum, unlike previous studies. Also, the buckled bar can still transfer significant angular momentum to the halo in the secular evolution phase, but it reduces with increasing halo spin. In the secular evolution phase, the bar strength increases and saturates to nearly equal values for all the models irrespective of halo spin and the sense of rotation with respect to the disk. The final boxy/peanut shape is more pronounced ($\sim$20 $\%$) in high spin halos having higher angular momentum in the inner region compared to non-rotating halos. We explain our results with angular momentum exchanges between the disk and halo.

14 pages,13 figures, 2 tables; Accepted for publication in ApJ

References in corpus (14)

• Array Programming with NumPy
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• The spin and shape of dark matter haloes in the Millennium simulation of a LambdaCDM universe
• Angular momentum properties of haloes and their baryon content in the Illustris simulation
• Three Mechanisms for Bar Thickening
• A Study of the Effect of Bulges on Bar Formation in Disk galaxies
• On the Correlation between Spin Parameter and Halo Mass
• Formation of young boxy/peanut bulges in ringed barred galaxies
• The Effect of Bulge Mass on Bar Pattern Speed in Disk Galaxies
• Violent Buckling Benefits Galactic Bars
• The effect of warm gas on the buckling instability in galactic bars
• Uncertainties in the Deprojection of the Observed Bar Properties
• Boxy Orbital Structures in Rotating Bar Models
• The Effect of Dark Matter Halo Shape on Bar Buckling and Boxy/Peanut Bulges

Cited by in corpus (9)

• Effects of the Central Mass Concentration on Bar Formation in Disk Galaxies
• Unveiling the origins of galactic bars: insights from barred and unbarred galaxies
• Origin of reduced dynamical friction by dark matter halos with net prograde rotation
• Modelling Dark Matter Halo Spin using Observations and Simulations: application to UGC 5288
• Dependence of galactic bars on the tidal density field in the SDSS
• Morphological evolution of disk galaxies and their concentration, asymmetry and clumpiness (CAS) properties in simulations across Toomre's $Q$ parameter
• The multi-dimensional halo assembly bias can be preserved when enhancing halo properties with HALOSCOPE
• Measuring the evolution of stellar bars with the host galaxy's spin
• Superbubbles as the source of dynamical friction: gas migration, stellar and dark matter contributions