Ultralight axions and the kinetic Sunyaev-Zel'dovich effect

Gerrit S. Farren, Daniel Grin, Andrew H. Jaffe, Renée HloŽek, David J.E. Marsh

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8 Citations (Scopus)


Measurements of secondary cosmic microwave background (CMB) anisotropies, such as the Sunyaev-Zel'dovich (SZ) effect, will enable new tests of neutrino and dark sector properties. The kinetic SZ (kSZ) effect is produced by cosmological flows, probing structure growth. Ultralight axions (ULAs) are a well-motivated dark-matter candidate. Here, the impact of ULA dark matter (with mass 10-27 to 10-23 eV) on kSZ observables is determined, applying new analytic expressions for pairwise cluster velocities and Ostriker-Vishniac signatures in structure-suppressing models. For the future CMB Stage 4 and ongoing Dark Energy Spectroscopic Instrument galaxy surveys, the kSZ effect (along with primary anisotropies) will probe ULA fractions ?a=?axion/?DM as low as ~5% if ma?10-27 eV (at 95% C.L.), with sensitivity extending up to ma?10-25 eV. If reionization and the primary CMB can be adequately modeled, Ostriker-Vishniac measurements could probe values ?a?10-3 if 10-27 eV?ma?10-24 eV, or ?a?1 if ma?10-22 eV, within the fuzzy dark matter window.

Original languageEnglish
Article number063513
JournalPhysical Review D
Issue number6
Publication statusPublished - 15 Mar 2022


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