NIHAO-XXIII: Dark Matter density shaped by Black Hole feedback

We present a systematic analysis of the reaction of dark matter distribution to galaxy formation across more than eight orders of magnitude in stellar mass. We extend the previous work presented in the NIHAO-IV paper (Tollet et al.) by adding 46 new high resolution simulations of massive galaxies performed with the inclusion of Black Hole feedback. We show that outflows generated by the AGN are able to partially counteract the dark matter contraction due to the large central stellar component in massive haloes. The net effect is to relax the central dark matter distribution that moves to a less cuspy density profiles at halo masses larger than $\approx 3 \times 10^{12}$ M$_{\odot}$. The scatter around the mean value of the density profile slope ($\alpha$) is fairly constant ($\Delta\alpha \approx 0.3$), with the exception of galaxies with halo masses around $10^{12}$ M$_{\odot}$, at the transition from stellar to AGN feedback dominated systems, where the scatter increases by almost a factor three. We provide useful fitting formulas for the slope of the dark matter density profiles at few percent of the virial radius for the whole stellar mass range: $10^5-10^{12}$ M$_{\odot}$ ($2 \times 10^9-5 \times 10^{13}$ M$_{\odot}$ in halo mass).
Comment: 5 pages, 4 figures, accepted for publication in MNRAS Letters