Photon and neutrino redshift in the field of braneworld compact stars
Abstract
We study gravitational redshift of photons and neutrinos radiated by the braneworld neutron or quark stars that are considered in the framework of the simple model of the internal spacetime with uniform distribution of energy density, and the external spacetime described by the ReissnerNordström geometry characterized by the braneworld ``tidal'' charge b. For negative tidal charges, the external spacetime is of the blackhole type, while for positive tidal charges, the external spacetime can be of both blackhole and nakedsingularity type. We consider also extremely compact stars allowing existence of trapped null geodesics in their interior. We assume radiation of photons from the surface at radius R, neutrinos from the whole compact star interior, and their motion along radial null geodesics of the spacetime. In dependency on the compact stars parameters b and R, the photon surface redshift is related to the range of the neutrino internal redshift and the signatures of the tidal charge and possible existence of extremely compact stars are discussed. When both surface (photon) and internal (neutrino) redshift are given by observations, both compact star parameters R and b can be determined in the framework of our simple model.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 July 2011
 DOI:
 10.1088/14757516/2011/07/012
 arXiv:
 arXiv:1108.5760
 Bibcode:
 2011JCAP...07..012H
 Keywords:

 General Relativity and Quantum Cosmology;
 Astrophysics  Solar and Stellar Astrophysics
 EPrint:
 JCAP07(2011)012