The Collimation of Relativistic Jets in Post-Neutron Star Binary Merger Simulations

Matteo Pais, Tsvi Piran, Yuri Lyubarsky, Kenta Kiuchi, Masaru Shibata

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


The gravitational waves from the binary neutron star merger GW170817 were accompanied by a multiwavelength 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, ∼5°, and powerful, ∼1050 erg, jet. We study the propagation of a Poynting flux-dominated jet within the merger ejecta (kinematic, neutrino-driven, and magnetorotational instability turbulence-driven) of a neutrino-radiation-GRMHD simulation of two coalescing neutron stars. We find that the presence of a postmerger low-density/low-pressure polar cavity, which 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 ∼4°-7° and an energy of 1049-1050 erg, in line with the observations of GW170817 and other sGRBs.

Original languageEnglish
Article numberL9
JournalAstrophysical Journal Letters
Issue number1
StatePublished - 1 Mar 2023

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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