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Recent results [1] on universal black holes in d dimensions are summarized. These are static metrics with an isotropy-irreducible homogeneous base space which can be consistently employed to construct solutions to virtually any metric theory of gravity in vacuum.

We prove that a generalized Schwarzschild-like ansatz can be consistently employed to construct d-dimensional static vacuum black hole solutions in any metric theory of gravity for which the Lagrangian is a scalar invariant constructed from the Riemann tensor and its covariant derivatives of arbitrary order. Namely, the base space can be taken to be any isotropy-irreducible homogeneous space (thus being Einstein), which generically reduces the field equations to two ODEs for two unknown functions. This is then exemplified by constructing solutions in particular theories such as Gauss-Bonnet, quadratic, F (R) and F (Lovelock) gravity, and certain conformal gravities. * sigbjorn.hervik@uis.no † ortaggio(at)math(dot)cas(dot)cz 1 It should be pointed out that not all static black holes can be written in the form (2). For example, in general relativity, five-dimensional static black rings [14] with a S 1 × S 2 horizon cannot (as follows from [15] and the comments on the Weyl type given below) -these, however, contain a conical singularity. Additionally, static black strings are also excluded by this ansatz, as they typically possess one (or more) privileged spatial direction(s) and a Kaluza-Klein-like asymptotics.

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We explore how far one can go in constructing d-dimensional static black holes coupled to p-form and scalar fields before actually specifying the gravity and electrodynamics theory one wants to solve. At the same time, we study to what extent one can enlarge the space of black hole solutions by allowing for horizon geometries more general than spaces of constant curvature. We prove that a generalized Schwarzschild-like ansatz with an arbitrary isotropy-irreducible homogeneous base space (IHS) provides an answer to both questions, up to naturally adapting the gauge fields to the spacetime geometry. In particular, an IHS–Kähler base space enables one to construct magnetic and dyonic 2-form solutions in a large class of theories, including non-minimally couplings. We exemplify our results by constructing simple solutions to particular theories such as $$R^2$$ R 2 , Gauss–Bonnet and (a sector of) Einstein–Horndeski gravity coupled to certain p-form and conformally invariant electrodynamics.