Constraints on decaying dark matter from weak lensing and cluster counts
Kari Enqvist, Seshadri Nadathur, Toyokazu Sekiguchi, Tomo Takahashi
Abstract
We revisit a cosmological constraint on dark matter decaying into dark radiation at late times. In Enqvist et al. (2015), we mainly focused on the effects of decaying dark matter (DDM) on the cosmic microwave background (CMB) and nonlinear matter power spectrum. Extending our previous analysis, here we use N-body simulation to investigate how DDM affects the halo mass function. This allows us to incorporate the cluster counts observed by the Sunyaev-Zel'dovich effect to study a bound on the lifetime of DDM. We also update the data of CMB and cosmic shear power spectrum with the Planck 2015 results and KiDS450 observations, respectively. From these cosmological observations, we obtain an lower bound on the lifetime Gamma(-1) >= 154 Gyr from the Planck2015 results (CMB+SZ cluster count) combined with the KiDS450 and the recent measurements of the baryon acoustic scale.