Structural and photometric properties of barred galaxies from the Auriga cosmological simulations

TL;DR

This study analyzes the structural and photometric properties of 21 barred galaxies from the Auriga simulations, showing they match observed properties and support secular evolution in a cosmological context.

Contribution

It demonstrates that state-of-the-art $ ext{Λ}$CDM simulations can reproduce observed bar structures and bulge properties in galaxies.

Findings

Wide range of bar sizes and luminosities consistent with observations

All bulges are pseudobulges with low Sersic indexes

Boxy/peanut structures identified in simulated bars

Abstract

In this work we analyse the structural and photometric properties of 21 barred simulated galaxies from the Auriga Project. These consist of Milky Way-mass magneto-hydrodynamical simulations in a $\Lambda$CDM cosmological context. In order to compare with observations, we generate synthetic SDSS-like broad-band images from the numerical data at z = 0 with different inclinations (from face-on to edge-on). Ellipse fits are used to determine the bar lengths, and 2D bulge/disc/bar decompositions with galfit are also performed, modelling the bar component with the modified Ferrer profile. We find a wide range of bar sizes and luminosities in the sample, and their structural parameters are in good agreement with the observations. All bulges present low S\'ersic indexes, and are classified as pseudobulges. In regard to the discs, the same breaks in the surface brightness profiles observed in real galaxies are found, and the radii at which these take place are in agreement with the observations. Also, from edge-on unsharp-masked images at z = 0, boxy or peanut-shaped (B/P) structures are clearly identified in the inner part of 4 bars, and also 2 more bars are found in buckling phase. The sizes of the B/P match fairly well with those obtained from observations. We thus conclude that the observed photometric and structural properties of galaxies with bars, which are the main drivers of secular evolution, can be developed in present state-of-the-art $\Lambda$CDM cosmological simulations.