We have succeeded in obtaining exact configurations of irrotational binary systems for compressible (polytropic) equations of state. Our models correspond to binaries of equal mass neutron star systems in the viscosity free limit. By using the obtained sequences of stationary states, the evolution of binary systems of irrotational neutron stars due to gravitational wave emission has been examin...

We study the final state of the gravitational collapse of uniformly rotating supramassive neutron stars by axisymmetric simulations in full general relativity. The rotating stars provided as the initial condition are marginally stable against quasiradial gravitational collapse and its equatorial radius rotates with the Kepler velocity (i.e., the star is at the mass-shedding limit). To model the...

We derive the relativistic equations for stellar perturbations, including in a consistent way shear viscosity in the stress-energy tensor, and we numerically integrate our equations in the case of large viscosity. We consider the slow rotation approximation, and we neglect the coupling between polar and axial perturbations. In our approach, the frequency and damping time of the emitted gravitat...

We investigate stability of a gravitationally collapsing iron core against non-spherical perturbation. The gravitationally collapsing iron core is approximated by a similarity solution for dynamically collapsing polytropic gas sphere. We find that the similarity solution is unstable against non-spherical perturbations. The perturbation grows in proportion to (t − t0) −σ while the the central de...

Growing evidence indicate supermassive black holes (SMBHs) in the mass range of MBH∼ 106− 10M⊙ lurking in central bulges of many galaxies [1, 2]. Extensive observations reveal fairly tight power laws of MBH versus the mean stellar velocity dispersion σ of the host bulge [3, 4, 5]. The dynamic evolution of a bulge and the formation of a central SMBH should be physically linked by various observa...