Effects of quasar feedback in galaxy groups

We study the effect of quasar feedback on distributions of baryons 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 10 galaxy group-sized dark matter haloes with masses in the range of 1-5 x 10(13) M-circle dot h(-1), star formation is suppressed by more than 50 per cent 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 haloes. As a result, the average gas density is 50 per cent lower in the inner region and 10 per cent higher in the outer region in the simulation, compared to a similar simulation with no quasar feedback. Gas pressure is also higher in the outer region, while temperature and entropy are enhanced in the inner region. The total group gas fraction in the two simulations generally differs by less than 10 per cent. We also find a small change of the total thermal Sunyaev-Zeldovich distortion, leading to 10 percent changes in the microwave angular power spectrum at angular scales below 2 arcmin.