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

Abstract

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 10 9 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 (m a 10 −9 eV) the cosmic magnetic fields might trigger ALP-photon conversions, while for masses m a 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.

Physics Beyond the Standard Model with BlackHawk v2.0

“…The previous version of the manual can be found on the arXiv [34] (v2), while the code is publicly available on HEPForge: https://blackhawk.hepforge.org/ The code has been recently presented to the TOOLS 2020 conference [35]. BlackHawk is used by many groups from very different domains of astrophysics and cosmology to perform striking studies including, to the knowledge of the authors, evolution of BHs spin [36], EGRB constraints with extended mass distributions and spinning BHs [37] or with higher dimensional Schwarzschild BHs [38], electron and positrons signals from the galaxy with the 511 keV line [39,40], current [41] or prospective [42] X-ray limits, neutrino constraints from Super-Kamiokande [40], JUNO [43] or prospective neutrino detectors [44,45], gamma ray constraints from INTEGRAL [46], COMPTEL with improved lowenergy secondary particles treatment [12], prospective AMEGO instrument [12,47], LHASSO [48] or fine modelisation of the Galaxy [49], prediction of signals from Planet 9 within the PBH hypothesis [50], archival galactic center radio observations [51], interstellar medium temperature in dwarf galaxies [52][53][54] or 21 cm measurements by EDGES with Schwarzschild [55] or Kerr PBHs [56], Big Bang nucleosynthesis (BBN) [57], heat flow from a small BH captured in the Earth core [58], warm DM from light Schwarzschild [22] and Kerr [23] PBHs, dark radiation from light spinning PBHs [23,24], (extended) dark sector emission [13,59], axion-like particle emission [60], HR from extended BH metrics…”