The superluminal motion of the jet launched in GW170817, the Hubble constant, and critical tests of gamma ray bursts theory

TL;DR

This paper links the superluminal jet in GW170817 to the Hubble constant, providing insights into gamma-ray burst mechanisms and testing cosmological models with jet motion observations.

Contribution

It demonstrates the connection between jet motion in GW170817 and local Hubble constant measurements, offering critical tests for gamma-ray burst theories.

Findings

Jet axis aligned with binary neutron star orbit

Hubble constant from jet motion matches local measurements

Superluminal motion constrains gamma-ray burst models

Abstract

The direction of the axis of the orbital motion of the merging binary neutron stars in the GW170817 event coincided with that of the apparent superluminal jet, which produced the short hard gamma ray burst (SHB) 170817A, if the local value of the Hubble constant is that provided by standard candle Type Ia supernovae, H_0=73.24 +/- 1.74 km/s Mpc. This value differs by 3 sigma from the cosmic value H_0=67.74 +/- 0.46 km/s Mpc obtained from the cosmic microwave background radiation by Planck assuming the standard Lambda-CDM cosmology. The measured superluminal motion of the jet also allows critical tests of the assumed production mechanism of SHBs in general and of SHB170817A in particular.