Electromagnetic instability of compact axion stars
Electromagnetic instability of compact axion stars
If the dark matter is composed of axions, then axion stars are expected to be abundant in the Universe. We demonstrate in fully nonlinear ($3+1$) numerical relativity the instability of compact axion stars due to the electromagnetic Chern-Simons term. We show that above the critical coupling constant ${g}_{a\ensuremath{\gamma}}^{\mathrm{crit}}\ensuremath{\propto}{M}_{s}^{\ensuremath{-}1.35}$, compact axion …