Discriminating and Constraining the Synchrotron and Inverse Compton Radiations from Primordial Black Hole and Dark Matter at the Galactic Centre Region

Abstract

The evaporations of Primordial Black Holes (PBH) (via Hawking radiation) can produce electrons/positrons (e − /e + ) in the Galactic Centre (GC) region which under the influence of the magnetic field of Centre region can emit synchrotron radiation. These e − /e + can also induce Inverse Compton radiation due to the scattering with ambient photons. In this work three different PBH mass distributions namely, monochromatic, power law and lognormal distributions are considered to calculate such radiation fluxes. On the other hand, annihilation or decay of dark matter in the Galactic Centre region can also yield e − /e + as the end product which again may emit synchrotron radiation in the Galactic magnetic field and also induce Inverse Compton scattering. In this work a comparative study is made for these radiation fluxes from both PBH evaporations and from dark matter origins and their detectabilities are addressed in various ongoing and other telescopes as well as in upcoming telescopes such as SKA. The variations of these radiation fluxes with the distance from the Galactic Centre are also computed and it is found that such variations could be a useful probe to determine the mass of PBH or the mass of dark matter.

Radio bounds on the mixed dark matter scenarios of primordial black holes and WIMPs

“…The radio observations can give complimentary to and in some cases tighter bounds on the DM properties than those from gamma rays [34][35][36][37][38]. There also have been the works discussing the radio signals from the evaporation of PBHs via Hawking radiation for which the typical PBH mass range explored is of order M P BH ∼ 10 15 − 10 17 g [39][40][41][42][43]. Our radio signal study explores the totally different PBH mass range of order a solar mass (1M ⊙ ∼ 2 × 10 33 g).…”

Limits on primordial black holes detectability with Isatis: A BlackHawk tool

“…to the change in the re-ionization history at the cosmic microwave background [21,22]. Other studies are based on the direct [23] or indirect detection of electrons-positrons [22,[24][25][26][27][28][29][30][31][32][33][34][35][36][37]; and finally there are some papers that focus on neutrino constraints [25,[38][39][40]. Most of the more recent studies now take into account the effect of having a non-zero PBH spin, which enhances the photon emission and thus results in more stringent constraints for Kerr (rotating) PBHs [9,13,18,19,25,28,32,37,40], or an extended PBH mass distribution, that should be more realistic regarding the channels of PBH formation [13,15,16,18,24,25,29,32,40].…”

Constraining PBH mass distributions from 21cm brightness temperature results and an analytical mapping between probability distribution of 21cm signal and PBH masses

“…Power law mass distribution of PBHs arises from the scale invariant density fluctuations or from the cosmic string collapse [28] and this mass distribution function is expressed as [28,29,44],…”

“…On the other hand, lognormal mass distribution of PBHs is considered when PBHs are formed from a smooth symmetric peak in the inflationary power spectrum [46]. The lognormal mass function is defined by [28,29,44],…”

“…In the present analysis, we attempt to study the mass distribution of PBHs in the context of the global 21cm signal. As it is suggested from recent studies that extended mass distribution of PBH could be favourable, we essentially focus on two special types of distribution function namely, power-law mass distribution [28,29] and lognormal mass distribution [28,29] and find constraints on the distribution parameters using the observed limit of EDGES experiment −500 +200 −500 mK .…”