New models for perfect fluids in EGB gravity
Abstract
We obtain new exact solutions to the field equations in the EinsteinGaussBonnet (EGB) modified theory of gravity for a fivedimensional spherically symmetric static matter distribution. By using a coordinate transformation, the study is reduced to the analysis of a single firstorder nonlinear differential equation which is an Abel equation of the second kind. Three classes of exact models are generated. The first solution has a constant density and a nonlinear equationofstate; it contains the familiar Einstein static universe as a special case. The second solution has variable energy density and is expressible in terms of elementary functions. The third solution has vanishing GaussBonnet coupling constant and is a fivedimensional generalization of the DurgapalBannerji model. The solution is briefly examined for physical admissibility. In particular, a set of constants is found which ensures that a pressurefree hypersurface exists which in turn defines the boundary of the distribution. The matter distribution is well behaved and the adiabatic sound speed criterion is also satisfied within the fluid ensuring a subluminal sound speed. Furthermore, the weak, strong and dominant conditions hold throughout the distribution.
 Publication:

International Journal of Modern Physics D
 Pub Date:
 April 2015
 DOI:
 10.1142/S0218271815500510
 Bibcode:
 2015IJMPD..2450051C
 Keywords:

 Einstein–Gauss–Bonnet;
 modified gravity;
 extended gravity;
 exact solutions;
 higherdimensional theory;
 04.20.Jb;
 04.20.Nr;
 04.70.Bw;
 Exact solutions;
 Classical black holes