Soliton Merger Rates and Enhanced Axion Dark Matter Decay
Abstract
Solitons are observed to form in simulations of dark matter (DM) halos consisting of bosonic fields. We use the extended PressSchechter formalism to compute the mass function of solitons, assuming various forms for the relationship between halo mass and soliton mass. We further provide a new calculation of the rate of soliton major mergers. Solitons composed of axion DM are unstable above a critical mass, and decay to either relativistic axions or photons, depending on the values of the coupling constants. We use the computed soliton major merger rate to predict the enhanced DM decay rate due to soliton instability. For certain values of currently allowed axion parameters, the energy injection into the intergalactic medium from soliton decays to photons is comparable to or larger than the energy injection due to core collapse supernovae at $z>10$. A companion paper explores the phenomenology of such an energy injection.
 Publication:

arXiv eprints
 Pub Date:
 January 2023
 DOI:
 10.48550/arXiv.2301.09769
 arXiv:
 arXiv:2301.09769
 Bibcode:
 2023arXiv230109769D
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 Astrophysics  High Energy Astrophysical Phenomena;
 High Energy Physics  Phenomenology
 EPrint:
 15 pages, 15 figures