Optical superluminal motion measurement in the neutron-star merger GW170817.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36224419.
- Also identified by DOI 10.1038/s41586-022-05145-7.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
The afterglow of the binary neutron-star merger GW1708171 gave evidence for a structured relativistic jet2-6 and a link3,7,8 between such mergers and short gamma-ray bursts. Superluminal motion, found using radio very long baseline interferometry3 (VLBI), together with the afterglow light curve provided constraints on the viewing angle (14-28 degrees), the opening angle of the jet core (less than 5 degrees) and a modest limit on the initial Lorentz factor of the jet core (more than 4). Here we report on another superluminal motion measurement, at seven times the speed of light, leveraging Hubble Space Telescope precision astrometry and previous radio VLBI data for GW170817. We thereby obtain a measurement of the Lorentz factor of the wing of the structured jet, as well as substantially improved constraints on the viewing angle (19-25 degrees) and the initial Lorentz factor of the jet core (more than 40).