Black Holes in the Dilatonic Einstein-Gauss-Bonnet Theory in Various Dimensions. IV - Topological Black Holes with and without Cosmological Term

We study black hole solutions in the Einstein gravity with Gauss-Bonnet term, the dilaton and a positive cosmological constant in various dimensions. Physically meaningful black holes with a positive cosmological term are obtained only for those in static spacetime with (D - 2)-dimensional hyperbolic space of negative curvature and D >= 5. We construct such black hole solutions of various masses numerically in D = 5, 6 and 10 dimensional spacetime and discuss their properties. In spite of the positive cosmological constant; the spacetime approach anti-de Sitter spacetime asymptotically. The black hole solutions exist for a certain range of the horizon radius, i.e., there are lower and upper bounds for the size of black holes. We also argue that, it is quite plausible that there is no black hole solution for hyperbolic space in the case of no cosmological constant.