3 research outputs found
Contributions from Dilatonic Strings to the Flat Behaviour of the Rotational Curves in Galaxies
We analyse the flat behaviour of the rotational curves in some galaxies in
the framework of a dilatonic, current-carrying string. We determine the
expression of the tangential velocity of test objects following a stable
circular equatorial orbit in this spacetime.Comment: This version to be published in the Int. Journal of Modern Phys.
On current-carrying cosmic strings and the generalized rainich algebra in scalar-tensor gravities
We obtain exact solutions for a static and charged cosmic string in a Einstein-Maxwell-Dilaton theory of a scalar-tensor type in (3+1)-Dimensions. This theory is specified by the dilaton field phi, the graviton field gµn and the electromagnetic field Fµn, and one post-Newtonian parameter alpha(phi). It contains three different cases, each of them corresponding to a particular solution of the Rainich algebra for the Ricci tensor