Fast galaxy bars continue to challenge standard cosmology

Abstract

Many observed disc galaxies harbour a central bar. In the standard cosmological paradigm, galactic bars should be slowed down by dynamical friction from the dark matter halo. This friction depends on the galaxy's physical properties in a complex way, making it impossible to formulate analytically. Fortunately, cosmological hydrodynamical simulations provide an excellent statistical population of galaxies, letting us quantify how simulated galactic bars evolve within dark matter haloes. We measure bar strengths, lengths, and pattern speeds in barred galaxies in state-of-the-art cosmological hydrodynamical simulations of the IllustrisTNG and EAGLE projects, using techniques similar to those used observationally. We then compare our results with the largest available observational sample at redshift $z=0$. We show that the tension between these simulations and observations in the ratio of corotation radius to bar length is $12.62\sigma$ (TNG50), $13.56\sigma$ (TNG100), $2.94\sigma$ (EAGLE50), and $9.69\sigma$ (EAGLE100), revealing for the first time that the significant tension reported previously persists in the recently released TNG50. The lower statistical tension in EAGLE50 is actually caused by it only having 5 galaxies suitable for our analysis, but all four simulations give similar statistics for the bar pattern speed distribution. In addition, the fraction of disc galaxies with bars is similar between TNG50 and TNG100, though somewhat above EAGLE100. The simulated bar fraction and its trend with stellar mass both differ greatly from observations. These dramatic disagreements cast serious doubt on whether galaxies actually have massive cold dark matter haloes, with their associated dynamical friction acting on galactic bars.

v3: Improved version accepted in MNRAS; Few typos fixed and one reference added

References in corpus (28)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• Ultralight scalars as cosmological dark matter
• Properties of galaxies reproduced by a hydrodynamic simulation
• Introducing the Illustris Project: the evolution of galaxy populations across cosmic time
• The Illustris simulation: the evolving population of black holes across cosmic time
• The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time
• The population of barred galaxies in the local universe I. Detection and characterisation of bars
• Galactic Angular Momentum in the Illustris Simulation: Feedback and the Hubble Sequence
• Galaxies as simple dynamical systems: observational data disfavor dark matter and stochastic star formation
• The Dependence of Bar Frequency on Galaxy Mass, Colour, and Gas Content -- and Angular Resolution -- in the Local Universe
• Feedback and the Structure of Simulated Galaxies at redshift z=2
• Dynamical friction in constant density cores: a failure of the Chandrasekhar formula
• A combined analysis of the $H_0$ late time direct measurements and the impact on the Dark Energy sector
• A massive blow for $\Lambda$CDM $-$ the high redshift, mass, and collision velocity of the interacting galaxy cluster El Gordo contradicts concordance cosmology
• The EAGLE simulations of galaxy formation: Public release of particle data
• Stellar mass distribution of S${}^4$G disk galaxies and signatures of bar-induced secular evolution
• Formation of the Large Nearby Galaxies
• Barred galaxies in the Illustris-1 and TNG100 simulations
• Tests of the Radial Tremaine-Weinberg Method
• SDSS-IV MaNGA: Bar pattern speed estimates with the Tremaine-Weinberg method and their error sources
• Applying the Tremaine-Weinberg Method to Nearby Galaxies: Stellar Mass-Based Pattern Speeds, and Comparisons with ISM Kinematics
• The global stability of M33: still a puzzle
• Barred spiral galaxies in modified gravity theories
• The effect of dust on Tremaine-Weinberg measurements
• Response of the integrals in the Tremaine-Weinberg method to multiple pattern speeds: a counter-rotating inner bar in NGC 2950?
• Evidence of a fast bar in the weakly-interacting galaxy NGC 4264 with MUSE
• GALAXY package for N-body simulation