Titol: Stability and physical properties of spherical excited scalar boson stars

Lloc: Seminari del DAA. Edifici Investigació Jeroni Muñoz, planta quarta, a Burjassot.

Dia: dimarts 28 de març de 2023. Hora: 12:00.

Resum:

We study the time evolution of spherical, excited -- with n radial nodes -- scalar boson stars in General Relativity minimally coupled to a complex massive scalar field with quartic self-interactions. We report that these stars, with up to n=10, can be made dynamically stable, up to timescales of t~10^4/(c mu), where mu is the inverse Compton wavelength of the scalar particle, for sufficiently large values of the self-interactions coupling constant lambda, which depend on n. We observe that the compactness of these solutions is rather insensitive to n, for large lambda and fixed frequency. Generically, along the branches where stability was studied, these excited boson stars are not compact enough to allow for ISCOs or light rings. Finally, we discuss the angular velocity of particles along timelike circular orbits, suggesting an application, for solutions in the Newtonian limit, to galactic rotation curves.