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Title: Recurrent axion stars collapse with dark radiation emission and their cosmological constraints
Axionlike dark matter whose symmetry breaking occurs after the end of inflation predicts enhanced primordial density fluctuations at small scales. This leads to dense axion minihalos (or miniclusters) forming early in the history of the Universe. Condensation of axions in the minihalos leads to the formation and subsequent growth of axion stars at the cores of these halos. If, like the QCD axion, the axionlike particle has attractive self-interactions there is a maximal mass for these stars, above which the star rapidly shrinks and converts an O(1) fraction of its mass into unbound relativistic axions. This process would leave a similar (although in principle distinct) signature in cosmological observables as a decaying dark matter fraction, and thus is strongly constrained. We place new limits on the properties of axionlike particles that are independent of their nongravitational couplings to the standard model.  more » « less
Award ID(s):
1915409 2210498
PAR ID:
10523422
Author(s) / Creator(s):
; ;
Publisher / Repository:
American Physical Society
Date Published:
Journal Name:
Physical Review D
Volume:
108
Issue:
9
ISSN:
2470-0010
Subject(s) / Keyword(s):
axions dark matter
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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