The baryonic mass assembly of low-mass halos in a -CDM Universe

DE ROSSI, M.E.; AVILA-REESE, V.; GONZÁLEZ-SAMANIEGO, A.; PEDROSA, S.E.

Tandil

Congreso; Reunión Anual Asociación Argentina de Astronomía; 2012

Asociacion Argentina Astronomía

We analyse the dark; gas; and stellar mass assembly histories of low-mass halos () identified at redshift in cosmological numerical simulations. Our results indicate that for halos in a given present-day mass bin; the gas-to-baryon fraction inside the virial radius does not evolve significantly with time; ranging from for smaller halos to for the largest ones. Most of the baryons are located actually not in the galaxies but in the intrahalo gas; for the more massive halos; the intrahalo gas-to-galaxy mass ratio is approximately the same at all redshifts; ; but for the least massive halos; it strongly increases with . The intrahalo gas in the former halos gets hotter with time; being dominant at ; while in the latter halos; it is mostly cold at all epochs. The multiphase ISM and thermal feedback models in our simulations work in the direction of delaying the stellar mass growth of low-mass galaxies.