Description
Stellar bars in disc galaxies grow as stars in near circular orbits lose angular momentum to their environments, including their Dark Matter (DM) halo, and transform into elongated bar orbits. This angular momentum exchange during galaxy evolution hints at a connection between bar properties, the DM angular momentum, specific angular momentum and halo spin λ, the dimensionless form of DM angular momentum. We investigate the connection between multiple DM halo properties and galaxy properties in the presence/absence of stellar bars, using the cosmological zoomed-in Auriga and Superstars simulations of Milky Way mass galaxies. We determine the bar strength (or bar amplitude, A2/A0), using Fourier decomposition of the face-on stellar density distribution. We determine the halo spin for barred and unbarred galaxies (0 < A2/A0 < 0.7) in the centre of the DM halo, close to the galaxy’s stellar disc. Previous studies using a large sample of disc galaxies from the magneto-hydrodynamic TNG50 simulations have shown an anti-correlation between halo spin and bar strength at redshift z=0, predicting a large population of barred galaxies to be found in lower spinning DM halos. To understand the role of stellar bars in transferring angular momentum from the disc to the DM halo we undertake further detailed investigation using high-resolution Auriga simulations, which follow the same galaxy formation model as the Illustris suite. I will present our findings from the Auriga simulations and compare them with previous results from the TNG50 simulations.
