Bound on induced gravitational wave background from primordial black holes

TL;DR

This paper constrains the energy density of the induced gravitational wave background across a wide frequency range using primordial black hole production limits, providing specific bounds near LIGO frequencies.

Contribution

It introduces new bounds on the induced gravitational wave background based on primordial black hole constraints, accounting for uncertainties in black hole formation parameters.

Findings

Induced gravitational wave energy density near 40 Hz cannot exceed (1-3)×10^{-7}.

Bounds vary due to uncertainties in black hole formation parameters.

Constraints are applicable across frequencies from 10^{-3} to 10^3 Hz.

Abstract

The today's energy density of the induced (second order) gravitational wave background in the frequency region $\sim 10^{-3} - 10^3$ Hz is constrained using the existing limits on primordial black hole production in the early Universe. It is shown, in particular, that at frequencies near $\sim 40$ Hz (which is the region explored by LIGO detector), the value of the induced part of $\Omega_{GW}$ cannot exceed $(1-3)\times 10^{-7}$. The spread of values of the bound is caused by the uncertainty in parameters of the gravitational collapse of black holes.