The collimation of relativistic jets in post-neutron star binary merger simulations

Abstract

The gravitational waves from the binary neutron star merger GW170817 were accompanied by a multi-wavelength electromagnetic counterpart, which confirms the association of the merger with a short gamma-ray burst (sGRB). The afterglow observations implied that the event was accompanied by a narrow, $\sim 5$deg, and powerful, $\sim 10^{50}$ erg, jet. We study the propagation of a Poynting flux-dominated jet within the merger ejecta (kinematic, neutrino-driven and MRI turbulence-driven) of a neutrino-radiation-GR-MHD simulation of two coalescing neutron stars. We find that the presence of a post-merger low-density/low-pressure polar cavity, that arose due to angular momentum conservation, is crucial to let the jet break out. At the same time the ejecta collimates the jet to a narrow opening angle. The collimated jet has a narrow opening angle of $\sim 4$-$7$ deg and an energy of $10^{49}$-$10^{50}$erg, in line with the observations of GW170817 and other sGRBs.

10 pages, 5 figures, 2 tables, accepted to ApJ Letters

References in corpus (16)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Multi-messenger Observations of a Binary Neutron Star Merger
• An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A
• INTEGRAL Detection of the First Prompt Gamma-Ray Signal Coincident with the Gravitational Wave Event GW170817
• The X-ray counterpart to the gravitational wave event GW 170817
• Illuminating Gravitational Waves: A Concordant Picture of Photons from a Neutron Star Merger
• A Radio Counterpart to a Neutron Star Merger
• Magnetic acceleration of ultra-relativistic jets in gamma-ray burst sources
• The rate, luminosity function and time delay of non-Collapsar short GRBs
• Off-axis prompt X-ray transients from the cocoon of short gamma-ray bursts
• First 100 ms of a long-lived magnetized neutron star formed in a binary neutron star merger
• The Broad-band Counterpart of the Short GRB 200522A at $z=0.5536$: A Luminous Kilonova or a Collimated Outflow with a Reverse Shock?
• Optical measurement of superluminal motion in the neutron-star merger GW170817
• Implementation of advanced Riemann solvers in a neutrino-radiation magnetohydrodynamics code in numerical relativity and its application to a binary neutron star merger
• Short gamma-ray burst jet propagation in binary neutron star merger environments
• Two steps forward and one step sideways: the propagation of relativistic jets in realistic binary neutron star merger ejecta

Cited by in corpus (2)

• A hybrid approach to long-term binary neutron-star simulations
• Exploring Jet Structure and Dynamics in Short Gamma Ray Bursts: A Case Study on GRB 090510