Effects of Baryonic Mass Loss on Galactic Dark Matter Halos

RAGONE FIGUEROA, CINTHIA; GRANATO, GIAN LUIGI; ABADI, MARIO GABRIEL

Buenos Aires

Workshop; Second Workshop on Numerical and Observational Astrophysics:"From the First Structures to the Universe Today"; 2011

Instituto de Astronomía y Física del Espacio - IAFE

We perform controlled numerical experiments (using the code GADGET-2) to asses the effect of baryon mass loss on theinner structure of large galactic dark matter halos. This mass expulsion is intended to mimic both the supernovae and AGNfeedbacks, as well as the evolution of stellar populations. In this study we are interested in particular on AGN feedback,which has been proposed to remove on a short timescale, of the order of a few dynamical times, a substantial fractionof the baryonic mass in massive forming spheroidal systems. In a previous study we have evaluated the observationalconsequences of this process on the galactic structure (Ragone-Figueroa & Granato 2011), while here we focus on thedistribution of dark matter in the galactic region. It is shown that the inner density profile of dark matter is flattened by asizeable amount, with little dependence on the expulsion timescale, at variance with recent claims (Ogiya & Mori 2011).