Effects of Hawking evaporation on PBH distributions

Abstract

Primordial black holes (PBHs) may lose mass by Hawking evaporation. For sufficiently small PBHs, they may lose a large portion of their formation mass by today, or evaporate completely if they form with mass $M<M_{\mathrm{crit}}\sim 5\times 10^{14}\mathrm{g}$. We investigate the effect of this mass loss on extended PBH distributions, showing that the shape of the distribution is significantly changed between formation and today. We reconsider the $\gamma$-ray constraints on PBH dark matter in the Milky Way center with a correctly `evolved' lognormal distribution, and derive a semi-analytic time-dependent distribution which can be used to accurately project monochromatic constraints to extended distribution constraints. We also derive the rate of black hole explosions in the Milky Way per year, finding that although there can be a significant number, it is extremely unlikely to find one close enough to Earth to observe. Along with a more careful argument for why monochromatic PBH distributions are unlikely to source an exploding PBH population today, we (unfortunately) conclude that we are unlikely to witness any PBH explosions.

15 pages, 6 figures. Comments welcome. Updated to match version accepted for publication

References in corpus (10)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• Constraints on Primordial Black Holes
• Primordial Black Holes as a dark matter candidate
• Microlensing and dynamical constraints on primordial black hole dark matter with an extended mass function
• Direct Detection of Hawking Radiation from Asteroid-Mass Primordial Black Holes
• Do Evaporating Black Holes Form Photospheres?
• Primordial Black Holes as Dark Matter: Converting Constraints from Monochromatic to Extended Mass Distributions
• Eliminating the LIGO bounds on primordial black hole dark matter
• Probing the Particle Spectrum of Nature with Evaporating Black Holes
• Physics Beyond the Standard Model with BlackHawk v2.0