Axion miniclusters made easy

• DOI: 10.1103/physrevd.103.083525
• Publication Date: 2021-04-27T18:07:55Z
• Authors: David Ellis; David J. E. Marsh; Christoph Behrens
• Keywords: High Energy Physics - Phenomenology; Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph); 0103 physical sciences; FOS: Physical sciences; 01 natural sciences; Astrophysics - Cosmology and Nongalactic Astrophysics

We use a modified version of the Peak Patch excursion set formalism to compute mass and size distribution QCD axion miniclusters from fully non-Gaussian initial density field obtained numerical simulations string decay. find strong agreement with N-Body at significantly lower computational cost. employ spherical collapse model provide fitting functions for barrier in radiation era. The halo function $z=629$ has power-law $M^{-0.6}$ masses within range $10^{-15}\lesssim M\lesssim 10^{-10}M_{\odot}$, all scaling as $(m_a/50\mu\mathrm{eV})^{-0.5}$. construct merger trees estimate redshift concentration relation, $C(M)$, which is well described using analytical results power spectrum linear growth. Using calibrated analytic extrapolate $z=0$, our method predicts mean $C\sim \mathcal{O}(\text{few})\times10^4$. low cost makes future investigation statistics rare, dense easy achieve.