2020/02/29 by Z. Wang, Zihang Wang, Lijing Shao +3 · 2 citations
Physics and Astronomy · #Axion #Cosmology and Gravitation Theories #Coupling (piping) #Dark Matter and Cosmic Phenomena #Dark matter #Gravitational wave #Hot dark matter #Instability #Parameter space #Pulsars and Gravitational Waves Research #Quantum chromodynamics #astro-ph.CO #hep-ph
paper · pdf · doi:10.1088/1475-7516/2020/07/038
published as JCAP 07 (2020) 038 · 25 pages, 5 figures, uses jcappub.sty
openalex created_date 2020/03/06 · arxiv created 2020/06/20 · openalex publication_date 2020/07/15 · arxiv updated 2020/07/20 · openalex updated_date 2026/08/05
Axion is a popular candidate for dark matter particles. Axionic dark matter may form Bose-Einstein condensate and may be gravitationally bound to form axion clumps. Under the presence of electromagnetic waves with frequency ω= m a / 2, where m a is the axion mass, a resonant enhancement may occur, causing an instability of the axion clumps. With analytical and numerical approaches, we study the resonant instability of axionic dark matter clumps with infinite homogeneous mass distribution, as well as distribution with a finite boundary. After taking realistic astrophysical environments into consideration, including gravitational redshift and plasma effects, we obtain an instability region in the axion density—clump size parameter space with given mass and coupling of axions. In particular, we show that, for axion clumps formed by the QCD axions in equilibrium, no resonant instability will occur.