GCN Circular 18364

J. Broderick (ASTRON), P.G. Jonker (SRON/RU), R.P. Fender (Oxford), A.
Rowlinson (UvA, ASTRON), R.A.M.J. Wijers (UvA), B.W. Stappers
(Manchester) report on behalf of the LOFAR Transients Key Science
project:

On Sept 21, 2015, starting at 06.00 (UTC), we observed a large fraction
of the localization error range at declinations larger than 0 degrees of
the Advanced LIGO trigger G184098 with the ILT (International
Low-Frequency Array [LOFAR] Telescope). The observations were obtained
with the High-Band Antennas (HBA) at a centre frequency of 145 MHz
(bandwidth 11.9 MHz). In this configuration, the ILT can provide 8
simultaneous beams on the sky, where each beam has a field of view of
approximately 12 deg^2 (beam FWHM 3.9 degrees). The beam centres are
given below:

1) 132.500000 5.166667 08:50:00.00 +05:10:00.0
2) 135.287125 5.166667 09:01:08.91 +05:10:00.0
3) 129.712875 5.166667 08:38:51.09 +05:10:00.0
4) 131.106458 7.572944 08:44:25.55 +07:34:22.6
5) 131.106458 2.760389 08:44:25.55 +02:45:37.4
6) 133.893542 7.572944 08:55:34.45 +07:34:22.6
7) 133.893542 2.760389 08:55:34.45 +02:45:37.4
8) 128.319333 2.760389 08:33:16.64 +02:45:37.4

The observations cover roughly 50 square degrees in total. Each field
was observed for a total of 3 hr with 10s time resolution after
pre-processing. These fields will be revisited two times with the same
exposures, on provisional time-scales of 1 month and 3 months. Analysis
is ongoing.

[GCN OPS NOTE(24sep15):  This Circular was originally published on 18:05421-Sep-2015 UT.]