The build-up of pseudobulges in a hierarchical universe

Understand

We study the cosmological build-up of pseudobulges using the LGalaxies semi-analytical model for galaxy formation with a new approach for following separately the assembly of classical bulges and pseudobulges.

• Classical bulges are assumed to be the result of violent processes (i.e., mergers and starbursts), while the formation of pseudobulges is connected to the secular growth of disks.
• We apply the model to both the Millennium and the Millennium II simulations, in order to study our results across a wide range of stellar masses ($10^{7} - 10^{11.5} M_{\odot}$).
• We find that $z=0$ pseudobulges mainly reside in galaxies of $ \rm M_{stellar} \sim 10^{10} - 10^{10.5} M_{\odot}$ ($\rm M_{halo} \sim 10^{11.5}-10^{12} M_{\odot}$) and we recover structural properties of these objects (e.g., sizes and bulge-to-total ratios) that are in good agreement with observational results.