Signatures of primordial black hole dark matter

Abstract

The nonbaryonic dark matter of the Universe is assumed to consist of new stable forms of matter. Their stability reflects symmetry of micro world and mechanisms of its symmetry breaking. In the early Universe heavy metastable particles can dominate, leaving primordial black holes (PBHs) after their decay, as well as the structure of particle symmetry breaking gives rise to cosmological phase transitions, from which massive black holes and/or their clusters can originate. PBHs can be formed in such transitions within a narrow interval of masses about 10 17 g and, avoiding severe observational constraints on PBHs, can be a candidate for the dominant form of dark matter. PBHs in this range of mass can give solution of the problem of reionization in the Universe at the redshift z ∼ 5 . . . 10. Clusters of massive PBHs can serve as a nonlinear seeds for galaxy formation, while PBHs evaporating in such clusters can provide an interesting interpretation for the observations of point-like gamma-ray sources. Analysis of possible PBH signatures represents a universal probe for super-high energy physics in the early Universe in studies of indirect effects of the dark matter.

Dark matter triggers of supernovae

“…While it is challenging to produce them through conventional standard model processes (see [9,10] for one mechanism), it is possible that new physics in the sector responsible for dark matter may produce them. There are constraints on such black holes being dark matter -if they are lighter than 10 17 gm, Hawking emission from them contributes too much to the observed cosmic ray spectrum.…”

Constraints on primordial black holes with extended mass functions

“…With the milestone discovery of the LIGO and VIRGO collaboration of black-hole binary mergers [3,4], the interest in the question of whether PBHs could constitute the dark matter (DM) [5] has recently been revived [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Depending on the mass scale(s) involved, the black holes potentially cause large observable effects.…”

Reionization effect enhancement due to primordial black holes

“…Mechanisms described in [4][5][6][7] may lead to formation of supermassive black holes. In the works [8][9][10], we explored the Hawking radiation of PBH for an explanation of the reionization at redshift z ∼ 8, which proved by the different observations [11,12]. We found that for a delta-function-like mass distribution, the effect can be reached within narrow mass interval around 5 × 10 16 g but only for z 4.…”

“…Given value has the sense of absorbed energy by baryonic matter due to ionization process (other processes of energy transfer from evaporation products to the baryonic matter can be neglected [9,10]). Note that it takes into account that energy absorption process takes a finite time so electrons emitted by the PBH have time to lose energy also due to scattering on CMB and due to the red shift.…”

“…There is a set of mechanisms (see reviews [4,5,9,13]) leading to a variety of PBH mass spectra. In this paper we consider those spectra of PBH masses that could explain the early reionization without connection to specific model.…”