[vsnet-grb-info 21041] LIGO/Virgo GW170817: A steep decline in the radio light curve and prediction for the X-rays

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23139
SUBJECT: LIGO/Virgo GW170817: A steep decline in the radio light curve and prediction for the X-rays
DATE:    18/08/13 18:38:03 GMT
FROM:    Tara Murphy at U of Sydney  <tara.murphy at sydney.edu.au>

D. Dobie (University of Sydney), K. Mooley (Caltech),
T. Murphy (University of Sydney), D. Kaplan (UWM), E. Lenc (CSIRO),
A. Corsi (TTU), D. Frail (NRAO), report on behalf of a larger collaboration
Our continued observations of GW170817 with the ATCA and the VLA up to 300
days post-merger (Mooley et al. in prep) confirm the t^(-2) decline in the
radio light curve initially reported in Mooley et al. 2018 (arXiv:1806.09693).
Such a slope rules out a cocoon-dominated outflow at late times, and is
instead the classic signature of a relativistic jet, consistent with the
VLBI result from Mooley et al. 2018. The t^(-2) decline is also expected in
the X-ray light curve, and may be confirmed by the Chandra observation carried
out on 2018 Aug 10.