TITLE:   GCN CIRCULAR
NUMBER:  21589
SUBJECT: LIGO/Virgo G298048: Further VLA Observations
DATE:    17/08/19 09:51:33 GMT
FROM:    Kate Alexander at Harvard U  <kalexander@cfa.harvard.edu>

K.D. Alexander (Harvard), W. Fong (Northwestern), and E. Berger (Harvard)
report on behalf of a larger collaboration:

We analyzed observations taken with the Very Large Array beginning on 2017
Aug 18 at 22:04:57 UT (1.39 d after the Fermi trigger time; Blackburn et
al., LVC GCN 21506). In two hours of observations at a mean frequency of
10.0 GHz, we detect the source reported in our previous VLA observations
(Alexander et al., LVC GCN 21545; 21548) and in ATCA observations
(Bannister et al., LVC GCN 21559) at a similar flux level. We measure an
improved position of:

RA = 13:09:47.704

Dec =-23:23:02.45

with an uncertainty of 0.1” in each coordinate. We note that the beam size
in our images is 3.1” by 1.4”, significantly smaller than our previous VLA
observations. The lack of variability over a 19.9 hr period along with full
spatial coincidence with NGC 4993 indicates that this radio emission is
originating from the host galaxy.

We further note that there is no detected emission at the position of the
optical transient (Coulter et al., LVC GCN 21529) down to a 3-sigma limit
of 17 microJy.