Models of rotating boson stars and geodesics around them: New type of orbits

Abstract

We have developed a highly accurate numerical code capable of solving the\ncoupled Einstein-Klein-Gordon system, in order to construct rotating boson\nstars in general relativity. Free fields and self-interacting fields, with\nquartic and sextic potentials, are considered. In particular, we present the\nfirst numerical solutions of rotating boson stars with rotational quantum\nnumber $k=3$ and $k=4$, as well as the first determination of the maximum mass\nof free-field boson stars with $k=2$. We have also investigated timelike\ngeodesics in the spacetime generated by a rotating boson star for $k=1$, $2$\nand $3$. A numerical integration of the geodesic equation has enabled us to\nidentify a peculiar type of orbits: the zero-angular-momentum ones. These\norbits pass very close to the center and are qualitatively different from\norbits around a Kerr black hole. Should such orbits be observed, they would put\nstringent constraints on astrophysical compact objects like the Galactic\ncenter.\n