A close look at secular evolution: Boxy/peanut bulges reduce gas inflow to the central kiloparsec

TL;DR

This study shows that boxy/peanut bulges significantly decrease gas inflow to galaxy centers, impacting galaxy evolution processes like star formation and active galactic nuclei fueling.

Contribution

It provides the first detailed hydrodynamic simulations quantifying how b/p bulges reduce central gas inflow in barred galaxies.

Findings

b/p bulges can reduce gas inflow by over an order of magnitude

the effect persists across different dark matter halo concentrations

reduction in central gas affects star formation and AGN activity

Abstract

In this letter we investigate the effect of boxy/peanut (b/p) bulges on bar-induced gas inflow to the central kiloparsec, which plays a crucial role on the evolution of disc galaxies. We carry out hydrodynamic gas response simulations in realistic barred galaxy potentials, including or not the geometry of a b/p bulge, to investigate the amount of gas inflow induced in the different models. We find that b/p bulges can reduce the gas inflow rate to the central kiloparsec by more than an order of magnitude, which leads to a reduction in the amount of gas available in the central regions. We also investigate the effect of the dark matter halo concentration on these results, and find that for maximal discs, the effect of b/p bulges on gas inflow remains significant. The reduced amount of gas reaching the central regions due to the presence of b/p bulges could have significant repercussions on the formation of discy- (pseudo-) bulges, on the amount of nuclear star formation and feedback, on the fuel reservoir for AGN activity, and on the overall secular evolution of galaxies.