Departament d'Astronomia i Astrofísica
Universitat de València |

A simplified waveless approximation --- a poor man's way of including GR effects in astrophysics

*Shin Yoshida*

*Department of Physics, Florida Atlantic University, EUA*

*Seminari del departament d'Astronomia i Astrofísica*

*Dijous 23 novembre 2006*

*11:00*

**Resum**

*A class of approximation of the general relativity is discussed, which allows to include the strong gravity into the Newtonian hydrodynamic simulation codes with minor modifications. New formulations are derived from a trancated system of Einstein equations in the isotropic coordinate, involves two or three potentials that satisfy elliptic equations, and are exact for static and spherically symmetric spacetime. Radial oscilllation of a spherically symmetric compact star is calculated for the new formulations, and compared with the result from the exact theory as well as the spatially conformal flat (Isenberg-Wilson-Mathews) formulation. The new simpler formulation reproduce the frequency as accurate as the spatially conformal flat formulation, hence the new formulation will be useful for investigate qualitative correction from the general relativistic gravity with much less computational efforts.*