Could GRB170817A be really correlated to a NS-NS merging?

TL;DR

This paper explores the potential correlation between the short GRB 170817A and a neutron star merger, analyzing observational data and theoretical models to understand the emission mechanisms and detection probabilities.

Contribution

It proposes a new interpretation of soft gamma-ray emission from neutron star mergers, suggesting a broader beaming angle for detectability compared to traditional models.

Findings

The observed GRB 170817A is consistent with a neutron star merger event.

Soft gamma-ray photons may have a wider emission cone, increasing detection chances.

A synchrotron radiation model explains the spread of gamma-ray emission from the merger.

Abstract

The exciting development of gravitational wave (GW) astronomy in the correlation of LIGO and VIRGO detection of GW signals makes possible to expect registration of effects of not only Binary Black Hole (BH) coalescence, but also Binary Neutron Star (NS) merging accompanied by electromagnetic (GRB) signal. Here we consider the possibility that a Neutron Star (NS), merging in a NS-NS or NS-BH system might be (soon) observed in correlation with any LIGO-VIRGO Gravitational Waves detection. We analyze as an example the recent case of the short GRB 170817A observed by Fermi and Integral. The associated Optical transient OT source in NGC4993 imply a rare near source, a consequent averaged large rate of such events (almost) compatible with expected NS NS merging rate. However the expected beamed GRB (or Short GRB) may be mostly aligned to a different direction than our. Therefore even soft GRB photons, more spread than hard ones, might be hardly able to shower to us. Nevertheless a prompt spiraling electron turbine jet in largest magnetic fields, at the base of the NS-NS collapse, might shine by its tangential synchrotron radiation in spread way with its skimming photons shining in large open disk. The consequent solid angle for such soft disk gamma radiation may be large enough to be nevertheless often observed.