Nariai black holes with quintessence
  In this paper we study the properties of Schwarzschild black hole surrounded by quintessence matter. The main objective of the paper is to show the existence of Nariai type black hole for special values of the parameters in the theory. The Nariai black hole with the quintessence has the topology $dS_2 \times S_2$ with $dS_2$ with a different scalar curvature than what would be expected for the Schwarzschild-de Sitter degenerate black hole. Temperature and the entropy for the Schwarzschild-de Sitter black hole and the Schwarzschild-quintessence black hole are compared. The temperature and the curvature are computed for general values of the state parameter $\omega$. 
Sharmanthie Fernando
gr-qc