GCN Circular 21975
Subject
LIGO/Virgo G298048: LWA radio observations
Date
2017-10-06T15:41:34Z (7 years ago)
From
Christopher League at FRBSG <cleague@gmail.com>
T. Callister (Caltech), J. Dowell (U New Mexico), J. Kanner (Caltech),
M. Kavic (LIU Brooklyn), C. League (LIU Brooklyn), P. Shawhan (U
Maryland), J. Simonetti (Virginia Tech), G. Taylor (U New Mexico), J.
Tsai (Virginia Tech), C. Yancey (U Maryland)
As previously reported (GCN 21680, GCN 21848), the Long Wavelength
Array (LWA1, located west of Socorro, New Mexico) followed up on
G298048 on 17 August and 24 August, observing with 4 beams: one
centered on NGC 4993, one including it off-center, and two nearby that
exclude the source.
After including observations from an additional epoch (30 August at
19:50 UTC, two weeks after the GW event), and further analysis, we
have concluded that the detection reported earlier (GCN 21848) is not
statistically significant. We now set 3-sigma upper limits to the
appearance of a radio source in an LWA1 beam centered on NGC 4993,
about 8 hours after the GW event, as ~200 Jy at 25 MHz and ~100 Jy
at 45 MHz.
A publication describing these limits and our analysis is in
preparation.