Gravitational Wave Production right after Primordial Black Hole Evaporation. (arXiv:2003.10455v1 [astro-ph.CO])

<a href="http://arxiv.org/find/astro-ph/1/au:+Inomata_K/0/1/0/all/0/1">Keisuke Inomata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kawasaki_M/0/1/0/all/0/1">Masahiro Kawasaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mukaida_K/0/1/0/all/0/1">Kyohei Mukaida</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Terada_T/0/1/0/all/0/1">Takahiro Terada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yanagida_T/0/1/0/all/0/1">Tsutomu T. Yanagida</a>

We discuss the footprint of evaporation of primordial black holes (PBHs) on

stochastic gravitational waves (GWs) induced by scalar perturbations. We

consider the case where PBHs once dominate the Universe but eventually

evaporate before the big bang nucleosynthesis. The reheating through the PBH

evaporation could end with a sudden change in the equation of state of the

Universe compared to the conventional reheating caused by particle decay. We

show that this “sudden reheating” by the PBH evaporation enhances the induced

GWs, whose amount depends on the length of the PBH-dominated era and the width

of the PBH mass function. We explore the possibility to constrain the

primordial abundance of the evaporating PBHs by observing the induced GWs. We

find that the abundance parameter $beta gtrsim 10^{-5} – 10^{-8}$ for

$mathcal{O}(10^3 – 10^5) , text{g}$ PBHs can be constrained by future GW

observations if the width of the mass function is smaller than about a

hundredth of the mass.

We discuss the footprint of evaporation of primordial black holes (PBHs) on

stochastic gravitational waves (GWs) induced by scalar perturbations. We

consider the case where PBHs once dominate the Universe but eventually

evaporate before the big bang nucleosynthesis. The reheating through the PBH

evaporation could end with a sudden change in the equation of state of the

Universe compared to the conventional reheating caused by particle decay. We

show that this “sudden reheating” by the PBH evaporation enhances the induced

GWs, whose amount depends on the length of the PBH-dominated era and the width

of the PBH mass function. We explore the possibility to constrain the

primordial abundance of the evaporating PBHs by observing the induced GWs. We

find that the abundance parameter $beta gtrsim 10^{-5} – 10^{-8}$ for

$mathcal{O}(10^3 – 10^5) , text{g}$ PBHs can be constrained by future GW

observations if the width of the mass function is smaller than about a

hundredth of the mass.

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