Posted by DK on December 21, 2017
Ever since its first detection on September 2, 2017, we have continued to monitor the radio emission from GW170817 with radio telescopes around the world including the Jansky Very Large Array (VLA), the Australia Telescope Compact Array (ATCA), and the Giant Metrewave Radio Telescope (GMRT). Today, in research published in Nature, we show that the radio emission has continued to get brighter. This is contrary to previous models where the radio is related to emission from a narrow, ultra-relativistic jet of material. Instead we believe that the afterglow of GW170817 is arising from a mildly relativistic wide-angle outflow moving towards us. The cocoon model, in which an ultra-relativistic jet dissipates its energy into the neutron-rich dynamical ejecta, can explain the gamma-rays, X-rays and radio emission from GW170817.