Feedback reshapes the baryon distribution within haloes, in halo outskirts, and beyond: the closure radius from dwarfs to massive clusters

Understand

We explore three sets of cosmological hydrodynamical simulations, IllustrisTNG, EAGLE, and SIMBA, to investigate the physical processes impacting the distribution of baryons in and around haloes across an unprecedented mass range of $10^8<M_{\rm 200c}/{\rm M_{\odot}}<10^{15}$, from the halo centre out to scales as large as $30\,R_{\rm 200c}$.

• We demonstrate that baryonic feedback mechanisms significantly redistribute gas, lowering the baryon fractions inside haloes while simultaneously accumulating this material outside the virial radius.
• To understand this large-scale baryonic redistribution and identify the dominant physical processes responsible, we examine several variants of TNG that selectively exclude stellar and AGN feedback, cooling, and radiation.
• We find that heating from the UV background in low-mass haloes, stellar feedback in intermediate-mass haloes, and AGN feedback in groups ($10^{12} \leq M_{\rm 200c}/{\rm M_{\odot}}<10^{14}$) are the dominant processes.