Ultra-fast jet observed flowing from a stellar collision

Using a collection of radio telescopes from the National Science Foundation, Caltech scientists have now confirmed that an ultra-fast jet had been produced by the neutron star collision. They confirmed that a jet of narrow material had been ejected at near light speeds as a result of a neutron star collision.

Scientists observed this collision on August 17, 2017, 130 million kilometers from Earth. At that time, using the interferometry laser observatory (LIGO), scientists observed that the collision produced gravitational waves parallel to a light flux in the form of gamma rays, X-rays , visible light and radio waves. This was the first cosmic event to be observed in gravitational waves and light waves.

Scientists have now concluded this after radio astronomers have found that a region of radio emissions created by the merger has evolved in a seemingly inconceivable way that can only be explained by the jet.

Kunal Mooley, a Caltech postdoctoral researcher nominated jointly with NRAO, said, "We measured an apparent motion four times faster than light. This illusion, called superluminal movement, occurs when the jet is directed almost to the Earth and the material in the jet is approaching the speed of light.

Assistant Professor of Astronomy Gregg Hallinan said, "We were lucky to observe this event because if the jet had been too far away from Earth, the radio show would have been too weak to be detected.

Radio observations were made using the Very Long Baseline Array Array (VLBA), the Robert C. Byrd Green Bank Telescope and the Very Large Array (VLA). The VLA is operated by the National Radio Astronomy Observatory (NRAO), which is closely associated with the other two telescopes involved in discovery.

Super fast jets are known to produce intense and short-lived gamma or GRB bursts, predicted by theorists to be associated with neutron star collisions. The observation of a jet associated with this collision is therefore an important confirmation of the theoretical expectations.

The consequences of the fusion are now better understood: the jet has probably interacted with the surrounding debris, forming a large "cocoon" of material that has spread outwards and accounted for the majority of the radio signal observed shortly after the collision . Later, the observed radio emission comes mainly from the jet.