Effects of Quasar Feedback in Galaxy Groups

Abstract

We study the effect of quasar feedback on distributions of baryons and properties of intracluster medium in galaxy groups using high-resolution numerical simulations. We use the entropy-conserving Gadget code that includes gas cooling and star formation, modified to include a physically-based model of quasar feedback. For a sample of ten galaxy group-sized dark matter halos with masses in the range of 1 to $5\times 10^{13} M_{\odot}/h$, star formation is suppressed by more than 50% in the inner regions due to the additional pressure support by quasar feedback, while gas is driven from the inner region towards the outer region of the halos. As a result, the average gas density is 50% lower in the inner region and 10% higher in the outer region in the simulation, compared to a similar simulation with no quasar feedback. Gas pressure is lowered by about 40% in the inner region and higher in the outer region, while temperature and entropy are enhanced in the inner region by about 20-40%. The total group gas fraction in the two simulations generally differs by less than 10%. We also find a small change of the total thermal Sunyaev-Zeldovich distortion, leading to 10% changes in the microwave angular power spectrum at angular scales below two arcminutes.