Project: 3D Soliton Stars
Project: 3D Soliton Stars We have numerically evolved 1D Boson stars in the ground state and the excited states, both with and without self-coupling. Spherically symmetric perturbations have been used to test the stability of various configurations. A lot of interesting physics has emerged from these studies. Stable ground state boson stars with and without self-coupling have very specific quasinormal modes of oscillations. These quasinormal modes are a signature of stability and are very important in predicting the final stable configuration that a perturbed boson star is going to settle into. Excited states of boson stars are important because they could be intermediate states during the formation process of boson stars. These are inherently unstable. If they cannot lose enough mass and make the transition to the ground state, they either form black holes or, as in the case of configurations with M > N*m (where M = mass of the star, N = number of bosons, m = mass of one boson) they disperse to infinity. During the transition process of excited states to ground states or black holes, these stars cascade through intermediate states like atomic transitions.The 3D problem, which we are now concentrating on, uses the G Code . Not only is this an interesting physics problem, but it is also a testbed of 3D spacetimes. We have made great strides in these 3D evolutions. It also can be used as a source of gravitational waves. The spherically symmetric problem (1D) involves scalar radiation. That is, perturbed stars lose mass by scalar radiation. Nonspherical perturbations result in gravitational waves. Evolving two three-dimensional scalar field configurations and studying their inspiral coalescence could have great astrophysical implications because the gravitational waves emitted may not sensitively depend on the internal structure of the compact objects.
For a description of the code that we use, see the G Code project. This project is also related to the Slicing/Shift Coordinate Conditions project, in which the choice and implementation of coordinate conditions in 3D Numerical Relativity is examined.