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Optical superluminal motion measurement in the neutron-star merger GW170817

Mooley, Kunal P. and Anderson, Jay and Lu, Wenbin (2022) Optical superluminal motion measurement in the neutron-star merger GW170817. Nature, 610 (7931). pp. 273-276. ISSN 0028-0836. doi:10.1038/s41586-022-05145-7.

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The afterglow of the binary neutron-star merger GW1708171 gave evidence for a structured relativistic jet and a link between such mergers and short gamma-ray bursts. Superluminal motion, found using radio very long baseline interferometry (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).

Item Type:Article
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URLURL TypeDescription ReadCube access
Mooley, Kunal P.0000-0002-2557-5180
Anderson, Jay0000-0003-2861-3995
Lu, Wenbin0000-0002-1568-7461
Additional Information:We thank A. Deller for pointing out the required correction for radio VLBI positions, for reading of the manuscript and for providing comments. K.P.M. thanks A. Krone-Martins for discussions, D. Frail for commenting on an early version of this manuscript and Y. Mooley for help with the Nature submission. K.P.M. is indebted to K. Gaura-Nitay for providing the impetus to execute this project. This research is based on observations made with the NASA/ESA Hubble Space Telescope obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with HST programmes GO-14771, GO-14804 and GO-15329. K.P.M. was a Jansky Fellow of the National Radio Astronomy Observatory and his work is currently supported through the National Research Foundation Grant AST-1911199. W.L. was supported by the David and Ellen Lee Fellowship at Caltech and Lyman Spitzer, Jr Fellowship at Princeton University.
Group:TAPIR, Walter Burke Institute for Theoretical Physics
Funding AgencyGrant Number
NASANAS 5-26555
National Radio Astronomy ObservatoryUNSPECIFIED
David and Ellen Lee Postdoctoral ScholarshipUNSPECIFIED
Princeton UniversityUNSPECIFIED
Issue or Number:7931
Record Number:CaltechAUTHORS:20221114-805047300.8
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:117856
Deposited By: Research Services Depository
Deposited On:29 Nov 2022 16:53
Last Modified:19 Jan 2023 17:15

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