Bulge formation scenarios …perspectives from a high-z observer

Abstract

I will present observational theoretical work on the formation bulges and pseudo-bulges in galaxies at high and low redshifts. Specifically, using the cosmological zoom-in simulations VELA, I will show how typical galaxies on the star-forming main sequence at redshift 2 can form a bulge component through rapid gas inflows, triggered by mergers, counter-rotating accretion streams, or violent disk instabilities. A comparison with our SINFONI-HST observations of stellar mass and star-formation rate profiles support this picture. In the second part, I will present how bulges and pseudo-bulges assemble in the new cosmological simulation IllustrisTNG. In particular, I discuss which physical processes are important to set the diversity of bulges in Milky Way like halos.