Cosmological Structure Formation in Decaying Dark Matter Models

Abstract

The standard cold dark matter (CDM) model predicts too many and too dense small structures. We consider an alternative model that the dark matter undergoes two-body decays with cosmological lifetime $\tau$ into only one type of massive daughters with non-relativistic recoil velocity $V_k$. This decaying dark matter model (DDM) can suppress the structure formation below its free-streaming scale at time scale comparable to $\tau$. Comparing with warm dark matter (WDM), DDM can better reduce the small structures while being consistent with high redshfit observations. We study the cosmological structure formation in DDM by performing self-consistent N-body simulations and point out that cosmological simulations are necessary to understand the DDM structures especially on non-linear scales. We propose empirical fitting functions for the DDM suppression of the mass function and the mass-concentration relation, which depend on the decay parameters lifetime $\tau$ and recoil velocity $V_k$, and redshift. The fitting functions lead to accurate reconstruction of the the non-linear power transfer function of DDM to CDM in the framework of halo model. Using these results, we set constraints on the DDM parameter space by demanding that DDM does not induce larger suppression than the Lyman-$\alpha$ constrained WDM models. We further generalize and constrain the DDM models to initial conditions with non-trivial mother fractions and show that the halo model predictions are still valid after considering a global decayed fraction. Finally, we point out that the DDM is unlikely to resolve the disagreement on cluster numbers between the Planck primary CMB prediction and the Sunyaev-Zeldovich (SZ) effect number count for $\tau \sim H_0^{-1}$.

35 pages, 20 figure, match the published version of JCAP

References in corpus (11)

• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• Planck 2015 results. XXIV. Cosmology from Sunyaev-Zeldovich cluster counts
• Can sterile neutrinos be ruled out as warm dark matter candidates?
• How cold is cold dark matter? Small scales constraints from the flux power spectrum of the high-redshift Lyman-alpha forest
• Relic keV sterile neutrinos and reionization
• The impact of dark matter decays and annihilations on the formation of the first structures
• Cosmological Simulations of Decaying Dark Matter: Implications for Small-scale Structure of Dark Matter Halos
• Dark Matter Halos with Cores from Hierarchical Structure Formation
• Dark-Matter Decays and Self-Gravitating Halos
• Dark-matter decays and Milky Way satellite galaxies
• Dark matter from late decays and the small-scale structure problems

Cited by in corpus (20)

• Dark matter, dark energy, and alternate models: A review
• A fresh look at linear cosmological constraints on a decaying dark matter component
• Decaying dark matter and the tension in ${\sigma }_8$
• Dark matter component decaying after recombination: lensing constraints with Planck data
• Cosmological constraints on late-universe decaying dark matter as a solution to the $H_0$ tension
• Cosmological Simulation for Fuzzy Dark Matter Model
• Cosmological constraints to dark matter with two- and many-body decays
• Constraints on decaying dark matter from weak lensing and cluster counts
• Predictions for the Abundance of High-redshift Galaxies in a Fuzzy Dark Matter Universe
• Escalating core formation with dark matter self-heating
• Probing the two-body decaying dark matter scenario with weak lensing and the cosmic microwave background
• Fully relativistic treatment of decaying cold dark matter in $N$-body simulations
• Sub-GeV Dark Matter Shining at Future MeV Gamma-Ray Telescopes
• Decaying axinolike dark matter: Discriminative solution to small-scale issues
• Evaluating Lyman-$\alpha$ Constraints for General Dark-Matter Velocity Distributions: Multiple Scales and Cautionary Tales
• Planck Scale Origin of Non-zero ${\theta }_{13}$ and Super-WIMP Dark Matter
• A frequentist view on the two-body decaying dark matter model
• Probing Non-Minimal Dark Sectors via the 21 cm Line at Cosmic Dawn
• Metamorphosis of dwarf halo density profile under dark matter decays
• Decaying Dark Matter: Simulations and Weak-Lensing Forecast