Journal Article

Compact radio emission indicates a structured jet was produced by a binary neutron star merger

Yang, J., Chassande-Mottin, E., Reynolds, C., Salafia, O. S., Salvaterra, R., Nava, L., Moldon, J., Bernardini, M. G., Blanchard, J., Beswick, R., Ghirlanda, G., An, T., Perez-Torres, M. A., Branchesi, M., Gurvits, L. I., Vergani, S. D., Venturi, T., Giroletti, M., Frey, S., Tagliaferri, G., Gawronski, M., Ghisellini, G., Paragi, Z., Colpi, M., Jonker, P. G., Covino, S., Marcote, B., Campana, S., D’Avanzo, P., Melandri, A., Perego, A., Agudo, I., Casadio, C., van Langevelde, H. J., D’Elia, V., Zhang, M.

2019

Overview

The binary neutron star merger event GW170817 was detected through both electromagnetic radiation and gravitational waves. Its afterglow emission may have been produced by either a narrow relativistic jet or an isotropic outflow. High-spatial-resolution measurements of the source size and displacement can discriminate between these scenarios. We present very-long-baseline interferometry observations, performed 207.4 days after the merger by using a global network of 32 radio telescopes. The apparent source size is constrained to be smaller than 2.5 milli–arc seconds at the 90% confidence level. This excludes the isotropic outflow scenario, which would have produced a larger apparent size, indicating that GW170817 produced a structured relativistic jet. Our rate calculations show that at least 10% of neutron star mergers produce such a jet.

• Publisher: American Association for the Advancement of Science,The American Association for the Advancement of Science
• Subject: Binary stars / Confidence intervals / Ejecta / Electromagnetic radiation / Emissions / Gravitation / Gravitational waves / Gravity / Interferometry / Interstellar matter / Neutron stars / Neutrons / Outflow / Radio / Radio emission / Radio sources (astronomy) / Radio telescopes / Relativism / Relativistic effects / Star mergers / Telescopes / Very long base interferometry