Gravitational-Wave Constraints on the Abundance of Primordial Black Holes

We thank T. Suyama for helpful comments. Top: The energy density of the induced GWs for the power spectrum for a peak width, Δ = 0.0, 1.0 × 10−3, 1.0 × 10−1, 1.0. Bottom: Energy density of scalar-induced GWs associated with PBH formation together with current pulsar constraint (thick solid line segment) and sensitivity of various GW detectors (convex curves). Solid wedged lines indicate the energy density with the parameters (ΩPBHh2, MPBH) = (10−5, 102M⊙) (left), (10−1, 1020g) (right) for sufficiently small Δ (thick lines) and Δ = 1.0 (thin lines).