Detectability of accretion-induced bosenovae in the Milky Way

We estimate collapse rates of axion stars in our galaxy based on the axion minicluster mass function of the Milky Way dark matter halo. We consider axionlike particles (ALP) with different temperature evolution of the axion mass, including the QCD axion with ma = 50 mu eV. Combining estimates for the present-day axion star mass function from our previous work with the axion star accretion model predicted by self-similar growth, we can infer the expected number of bosenovae occurring within the Milky Way. Our estimates suggest that for an observation time of tobs = 1 yr, the majority of the up to 1013 bosenovae per galaxy occur in the densest miniclusters with initial overdensity parameter Phi 104. We discuss the detectability of such recurring axion bursts within our galactic vicinity and find that, for models with ments can probe a large range of ALP masses ma 10-6 eV and with moderate improvements even the quantum chromodynamics axion case. For axions with nonderivative-type interactions like the axionphoton coupling, our analysis suggests that optimistic predictions with order-one dark matter abundance of axion stars f star 1 can be probed by dedicated burst searches.