Galaxies with monstrous black holes in galaxy cluster environments

Understand

Massive early-type galaxies follow a tight relation between the mass of their central supermassive black hole ($\rm M_{BH}$) and their stellar mass ($\rm M_{\star}$).

• The origin of observed positive outliers from this relation with extremely high $\rm M_{BH}$ ($> 10^{9} M_{\odot}$) remains unclear.
• We present a study of such outliers in the Hydrangea/C-EAGLE cosmological hydrodynamical simulations, designed to enable the study of high-mass galaxy formation and evolution in cluster environments.
• We find 69 $M_{\rm BH}(M_{\star})$ outliers at $z=0$, defined as those with $ \rm M_{BH} >10^{7} M_{\odot}$ and $\rm M_{BH}/\rm M_{\star}> 0.01$.