Ultra-light axions and the kinetic Sunyaev-Zel'dovich Effect

Understand

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.
• Ultra-light axions (ULAs) are a well-motivated dark-matter candidate.
• Here the impact of ULA dark matter (with mass $10^{-27}~{\rm eV}$ to $10^{-23}~{\rm eV}$) on kSZ observables is determined, applying new analytic expressions for pairwise cluster velocities and Ostriker-Vishniac signatures in structure-suppressing models.