Effects of Quasar Feedback in Galaxy Groups

TL;DR

This study uses high-resolution simulations to analyze how quasar feedback influences baryon distribution and intracluster medium properties in galaxy groups, revealing significant impacts on gas density, pressure, and temperature.

Contribution

It introduces a physically-based quasar feedback model into simulations, showing its effects on baryon distribution and intracluster medium in galaxy groups.

Findings

Star formation suppressed by over 50% in inner regions due to quasar feedback.

Gas density in inner regions reduced by 50%, increased by 10% in outer regions.

Minor changes in total gas fraction and a 10% variation in the Sunyaev-Zeldovich effect.

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.