ATCA observations of
GRB980109
These results have been obtained as part of project C651 by D.A. Frail,
S.R. Kulkarni, M.H. Wieringa, R.M. Wark, J.L. Higdon and the BeppoSAX GRB team.
Permission to quote results should be obtained from Dale Frail
(dfrail@aoc.nrao.edu).
Observations on 98:01:09
-
a series of short scans from 98JAN09:08:49:05.0 to
98JAN09:14:26:25.0. Total integration 1.6 hours at 20cm (1384 MHz) and
13cm (2496 MHz) pointing at the center of the BeppoSAX error circle
(RA 00:25:56.0 Dec -63:01:26.0). The primary beam FWHM is 33' and 22'
respectively.
-
The 20cm image has an rms
of 0.16 mJy. Here's a
list with 5 sigma detections in a 23'x17' box (corresponding to
the top 17' of the image).
-
The 13cm image has an rms
of 0.16 mJy. Here's a
list with 5 sigma detections in a 23'x17' box. Sources near the
top of the image are strongly attenuated.
Observations on 98:01:10
-
Four 15min scans from 98JAN10:00:21 and
almost 6h from 98JAN10:08:22 - 98JAN10:14:02 pointing at the center of
the BeppoSAX error circle. Total integration time 5.7h at 20cm (1384 MHz) and
13cm (2496 MHz).
- The 20cm image has an rms
of 0.13 mJy. Here's a
list with 5 sigma detections in a 23'x17' box (corresponding to
the top half of image).
- The 13cm image has an rms
of 0.083 mJy. Here's a
list with 5 sigma detections in a 23'x17' box.
Observations on 98:01:14
-
14 5 min scans from 98JAN14:09:29 to 98JAN14:13:10
Total integration time 1.4h at 6cm (4800 MHz) and 3cm (8640 MHz)
pointing at the intersection of the BeppoSAX 10' error circle and
the IPN strip: RA 00:25:23 Dec -62:52:00. Primary beam FWHM is 10' and
5' respectively.
- The 6cm image has an rms
of 0.11 mJy. There is one clear detection of 0.9 mJy at
RA 00:25:27.07 Dec -62:49:18.5, 2.7' from the intersection.
Here's a
list with three 5-sigma detections in a 10'x10' box.
- The 3cm image has an rms
of 0.12 mJy and shows no 5-sigma detections over a 5'x5' area.
Observations on 98:01:15
- 9 hour observation, with secondary every 15 min, starting
98JAN15:05:27 and ending 98JAN15:15:16. Total integration time 8.2h at
6cm (4800 MHz) and 3cm (8640 MHz) pointing at RA 00:25:23 Dec
-62:52:00.
- The 6cm image has an rms
of 0.049 mJy. Yesterdays detection is there at the same level, and
turns out to be very elongated (the automated fit fails), here's a
closeup of the source.
Here's a
list with 5-sigma detections in a 10'x10' box.
- A close-up
of the region with a possible optical transient. The nearest peak
is 0.17 mJy (~3-sigma) at 0:25:43.253, -62:52:35.38.
- The 3cm image has an rms
of 0.048 mJy and shows no 5-sigma detections over a 10'x10' area.
A close-up
of the region with a possible optical transient shows no significant peak.
Last changed on: 19-JAN-1998
Mark.Wieringa@csiro.au
