Josh Eby (University of Cincinnati)

Self-Interacting Dark Matter and Boson Stars

I review our recent work in scalar field dark matter, in particular the study of gravitationally bound Bose-Einstein condensates known as Boson Stars. Galaxy cluster collisions and small-scale observations in galaxies set constraints on the self-interactions of dark matter particles, which are important in determining the allowed masses of boson stars. First, the available parameter space for "heavy" (m > eV) scalar particles will be presented. Next, I examine very light scalars, considering in detail the case of axions and axion stars. Our results include the macroscopic parameters of axion stars, a study of possible decay modes through self-interactions or tunneling effects, and a brief foray into possible detection signatures.