Black holes in an expanding universe and supersymmetry

Understand

This paper analyzes the supersymmetric solutions to five and six-dimensional minimal (un)gauged supergravities for which the bilinear Killing vector constructed from the Killing spinor is null.

• We focus on the spacetimes which admit an additional ${\rm SO}(1,1)$ boost symmetry.
• Upon the toroidal dimensional reduction along the Killing vector corresponding to the boost, we show that the solution in the ungauged case describes a charged, nonextremal black hole in a Friedmann-Lema\^itre-Robertson-Walker (FLRW) universe with an expansion driven by a massless scalar field.
• For the gauged case, the solution corresponds to a charged, nonextremal black hole embedded conformally into a Kantowski-Sachs universe.