27–29 Oct 2021
IBS-CTPU
Asia/Seoul timezone

Axion-like particles from primordial black holes shining through the Universe

29 Oct 2021, 17:10
1h
Zoom (IBS-CTPU)

Zoom

IBS-CTPU

CTPU, 4th floor Theory Building, IBS, Daejeon

Speaker

Francesco Schiavone (Bari U)

Description

We consider a cosmological scenario in which the very early Universe experienced a transient epoch of matter domination due to the formation of a large population of primordial black holes (PBHs) with masses M . 109 g, that evaporate before Big Bang nucleosynthesis. In this context, Hawking radiation would be a non-thermal mechanism to produce a cosmic background of axion-like particles (ALPs). We assume the minimal scenario in which these ALPs couple only with photons. In the case of ultralight ALPs (with masses less than 10^-9 eV), the cosmic magnetic fields might trigger ALP-photon conversions, while for masses heavier than 10 eV spontaneous ALP decay in photon pairs would be effective. We investigate the impact of these mechanisms on the cosmic X-ray background, on the excess in X-ray luminosity in Galaxy Clusters, and on the process of cosmic reionization.

Presentation materials