Particle decay in the early universe: predictions for 21 cm

Abstract

The influence of ultra-high energy cosmic rays (UHECRs) and decaying dark matter particles on the emission and absorption characteristics of neutral hydrogen in 21 cm at redshifts $z=10-50$ is considered. In presence of UHECRs 21 cm can be seen in absorption with the brightness temperature $T_b=-(5-10)$ mK in the range $z=10-30$. Decayng particles can stimulate a 21 cm signal in emission with $T_b\sim 50-60$ mK at $z=50$, and $T_b\simeq 10$ mK at $z\sim 20$. Characteristics of the fluctuations of the brightness temperature, in particular, its power spectrum are also calculated. The maps of the power spectrum of the brightness temperature on the plane {\it wavenumber-redshift} are shown to be sensitive to the parameters of UHECRs and decaying dark matter. Observational possibilities to detect manifestations of UHECRs and/or decaying particles in 21 cm with the future radio telescopes (LOFAR, 21CMA and SKA), and to distinguish contributions from them are briefly discussed.

10 pages, 9 figures, accepted in MNRAS

References in corpus (7)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Impact of dark matter decays and annihilations on reionization
• The Effects of Dark Matter Decay and Annihilation on the High-Redshift 21 cm Background
• The impact of dark matter decays and annihilations on the formation of the first structures
• The 21 Centimeter Forest
• The Spin-Resolved Atomic Velocity Distribution and 21-cm Line Profile of Dark-Age Gas
• The influence of ultra-high-energy cosmic rays on star formation in the early universe

Cited by in corpus (4)

• The 21cm angular-power spectrum from the dark ages
• The Energy Cascade from Warm Dark Matter Decays
• Radiative Transfer Effect on Ultraviolet Pumping of the 21cm Line in the High Redshift Universe
• The 21cm Signature of Early Relic \HII Regions