Numerical simulations of bar formation in the Local Group

Abstract

More than 50 per cent of present-day massive disc galaxies show a rotating stellar bar. Their formation and dynamics have been widely studied both numerically and observationally. Although numerical simulations in the $\Lambda$CDM cosmological framework predict the formation of such stellar components, there seems to be a tension between theoretical and observational results. Simulated bars are typically larger in size and have slower pattern speed than observed ones. We study the formation and evolution of barred galaxies, using two $\Lambda$CDM zoom-in hydrodynamical simulations of the CLUES project that follow the evolution of a cosmological Local Group-like volume. We found that our simulated bars, at $z=0$, are both shorter and faster rotators than previous ones found in other studies on cosmological simulations alleviating the tension mentioned above. These bars match the short tail-end of the observed bar length distribution. In agreement with previous numerical works, we find that bars form in those systems where the disc self-gravity is dominant over the dark matter halo, making them unstable against bar formation. Our bars developed in the last 3-4 Gyr until they achieve their current length and strength; as bars grow, their lengths increase while their rotation speeds decrease. Despite this slowdown, at redshift $z=0$ their rotation speeds and size match well the observational data.

11 pages, 9 figures. Accepted for publication in MNRAS

References in corpus (9)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Star Formation and Feedback in Smoothed Particle Hydrodynamic Simulations--I. Isolated Galaxies
• Dynamics of Barred Galaxies
• Feedback and the Structure of Simulated Galaxies at redshift z=2
• Disc instabilities and semi-analytic modelling of galaxy formation
• Bar-Halo Friction in Galaxies III: Halo Density Changes
• Size matters: abundance matching, galaxy sizes, and the Tully-Fisher relation in EAGLE
• Kinematic clues to bar evolution for galaxies in the local universe: why the fastest rotating bars are rotating most slowly
• Cosmic evolution of bars in simulations of galaxy formation

Cited by in corpus (5)

• Effects of the Central Mass Concentration on Bar Formation in Disk Galaxies
• Unveiling the origins of galactic bars: insights from barred and unbarred galaxies
• The bar rotation rate as a diagnostic of dark matter content in the centre of disc galaxies
• Bar instability and formation timescale across Toomre's $Q$ parameter and central mass concentration: slow bar formation or true stability
• Disc instability and bar formation: view from the IllustrisTNG simulations