Dense gas formation and destruction in a simulated Perseus-like galaxy
  cluster with spin-driven black hole feedback
  Extended filamentary H$\alpha$ emission nebulae are a striking feature of
nearby galaxy clusters but the formation mechanism of the filaments, and the
processes which shape their morphology remain unclear. We conduct an
investigation into the formation, evolution and destruction of dense gas in the
center of a simulated, Perseus-like, cluster under the influence of a
spin-driven jet. We particularly study the role played by condensation of dense
gas from the diffuse intracluster medium, and the impact of direct uplifting of
existing dense gas by the jets, in determining the spatial distribution and
kinematics of the dense gas. We present a hydrodynamical simulation of an
idealised Perseus-like cluster using the adaptive mesh refinement code {\sc
ramses}. Our simulation includes a supermassive black hole (SMBH) that
self-consistently tracks its spin evolution via its local accretion, and in
turn drives a large-scale jet whose direction is based on the black hole's spin
evolution. We show that the formation and destruction of dense gas is closely
linked to the SMBH's feedback cycle, and that its morphology is highly variable
throughout the simulation. While extended filamentary structures readily
condense from the hot intra-cluster medium, they are easily shattered into an
overly clumpy distribution of gas during their interaction with the jet driven
outflows. Condensation occurs predominantly onto infalling gas located 5 - 15
kpc from the center during quiescent phases of the central AGN, when the local
ratio of the cooling time to free fall time falls below 20, i.e. when $t_{\rm
cool}/t_{\rm ff} < 20$. We find evidence for both condensation and uplifting of
dense gas, but caution that purely hydrodynamical simulations struggle to
effectively regulate the cluster cooling cycle and produce overly clumpy
distributions of dense gas morphologies, compared to observation.
