Looking for Black Hole Morsels in Astrophysical Mergers via Hawking Radiation

TL;DR

This paper proposes that micro-black holes formed during astrophysical mergers could emit detectable Hawking radiation as gamma ray bursts, offering a new way to test physics beyond General Relativity.

Contribution

It introduces the hypothesis of morsel formation during mergers and predicts observable gamma ray signatures from Hawking radiation, which can be tested with current telescopes.

Findings

Gamma ray bursts with TeV energies could originate from morsel Hawking radiation.

Time delay from gravitational wave events correlates with morsel mass distribution.

Current telescopes could detect or constrain the total mass of morsels formed during mergers.

Abstract

Gravitational wave observation has provided numerous insights into the merger of astrophysical black holes. In contrast to other violent events (e.g. supernovae), they are, however, not expected to lead to significant emissions of photons and neutrinos. In this paper we discuss a scenario that would lead to characteristic observable gamma ray bursts, which would provide numerous hints to physics beyond General Relativity. Starting from the hypothesis that micro-black holes (called morsels) are formed during the merger process, we show that it is possible to observe their Hawking radiation, which takes the form of gamma ray bursts of a uniquely characteristic form: with energies in the TeV range, their temporal structure is unlike that stemming from any other astrophysical event. Notably, the time delay from the gravitational wave event is correlated to the mass distribution of the morsels. The integrated mass of the morsels, allowed by the unaccounted merger mass, leads to a Hawking radiation in photons that is above the sensitivity of atmospheric Cherenkov telescopes such as HESS, LHAASO and HAWC, and gamma ray space telescopes, such as Fermi-LAT. This renders the hypothesis of morsel creation experimentally testable, and we provide the first concrete bounds on the total mass of morsels formed in specific events.