A dark matter component decaying after recombination: lensing constraints with Planck data

Anton Chudaykin,Dmitry Gorbunov,Igor Tkachev,V.A Andrianov,V.A Rubakov,V.A Matveev,A.A Andrianov,M.D Fitkevich,V.T Kim

doi:10.1051/epjconf/201612503004

Abstract

It was recently proposed [1] that the model with a fraction of decaying cold dark matter is able to reconcile measurements in high redshift (CMB) and low redshift (probes of cluster abundance and the Hubble constant). We check this statement employing the full likelihood of CMB Planck data. We find that the lensing effect calculated from anisotropy spectra measured by Planck imposes the strong constraint on the fraction of unstable dark matter as F F ≈ 2 − 5% improves the goodness-of-fit by 1.5 − 2σ depending on A s and τ priors in comparison with the concordance ΛCDM model.

Highlights

The nature of dark matter and dark energy in the Universe remains mysterious
In recent paper [1] the authors consider the model with a subdominant fraction of dark matter decaying after recombination and argued that such a model is able to reconcile the emerging tension between the cosmological probes in high redshift and low redshift. They reveal that the model under consideration explains extremely high value of the Hubble constant h = 0.738 ± 0.024 [2], h = 0.743 ± 0.021 [3] obtained in observations of astronomical Standard Candles in comparison with the corresponding value h = 0.6727 ± 0.0066 extracted from Planck spectra using TT, TE, EE + lowP dataset in notations of the original paper [4]
We emphasize the particular role of the lensing effect which affects the TT power spectrum. For this purpose we depict the difference in this quantity between Decaying Dark Matter (DDM) (F = 0.1, Γ = 2000 km/s/Mpc) and ΛCDM predictions assuming the other parameters are fixed to the best-fit values obtained in TT, TE, EE + lowP analysis

Summary

Introduction

The nature of dark matter and dark energy in the Universe remains mysterious. Order-of-magnitude equality between contributions of baryonic matter and dark matter to the energy density of the Universe today is treated as a chance coincidence. In recent paper [1] the authors consider the model with a subdominant fraction of dark matter decaying after recombination and argued that such a model is able to reconcile the emerging tension between the cosmological probes in high redshift and low redshift They reveal that the model under consideration explains extremely high value of the Hubble constant h = 0.738 ± 0.024 [2], h = 0.743 ± 0.021 [3] obtained in observations of astronomical Standard Candles in comparison with the corresponding value h = 0.6727 ± 0.0066 extracted from Planck spectra using TT, TE, EE + lowP dataset in notations of the original paper [4]. We check the consistency of the model with the galaxy cluster counts measured by Planck via Sunyaev-Zeldovich effect [4] which prefer lower values of σ8

Objectives

Methods

Findings

Conclusion