Microstates of AdS$_5$ black holes with hypermultiplets

We construct supersymmetric rotating AdS$_5$ black holes in 5d $\mathcal{N}=2$ gauged supergravity coupled to two vector multiplets and a universal hypermultiplet, and verify their microscopic counting from the superconformal index of the dual 4d class $\mathcal{S}$ $\mathcal{N}=1$ SCFTs. From the CFT, we perform the Legendre transform of the index to the microcanonical ensemble. The theories are parametrized by a rational number $z$ which enters into the extremization equations making them more challenging to solve. We present a method to address these difficulties and highlight the subtleties involved. From the gravity perspective, we identify a charged, rotating black hole whose Bekenstein-Hawking entropy matches the prediction from the index for $z=\pm1$. Beyond this value, where hypermultiplet scalars are nonzero, we construct the near-horizon extremal geometry perturbatively around $z= 1$ and verify that the entropy is consistent with the CFT prediction. We discuss the thermodynamics and verify the near-horizon versions of the first law of thermodynamics and the supersymmetric condition. In this setting, our analysis characterizes the first construction of a rotating black hole geometry in a 5d $\mathcal{N}=2$ supergravity theory that contains hypermultiplets.