The Austral
ia Telescope National Facility

ATCA observations of GRB980425

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).
All coordinates are J2000.

Summary of observations

The GRB field

The 6cm radio image taken on May 7, 1998 with the Australia Telescope Compact Array. Superimposed are the 8' BeppoSAX Wide Field Camera (WFC) error circle and the two 1' Narrow Field Instrument (NFI) error circles (source 1 was previously unknown, but has remained constant and is thus unlikely to be related to the Gamma Ray Burst; source 2 was a faint transient source only seen once). The positions of the variable radio source and the optical supernova coincide and are marked with SN1998bw.

Spectral evolution

Radio lightcurves

Table of Observations

Date (UT)	Day	S20 (mJy)	S13 (mJy)	S6 (mJy)	S3 (mJy)	Config	Integration (h)
1998 Apr 28	3.0			9.0 +/- 0.5	13.0 +/- 0.6	750A	3.1
1998 Apr 29	4.0			9.9 +/- 0.5	13.0 +/- 0.6	750A	2.2
1998 May 05	9.9			39.0 +/- 0.8	48.0 +/- 1.0	750A	8.8
1998 May 07	11.7	6.2 +/- 0.5	19.7 +/- 0.6	44.6 +/- 0.9	49.4 +/- 1.0	750A	2.6
1998 May 10	14.7	7.7 +/- 0.5	22.3 +/- 0.7	39.9 +/- 0.9	37.6 +/- 0.8	750A	1.6
1998 May 11	15.7	9.2 +/- 0.5	23.5 +/- 0.7	37.4 +/- 0.8	34.3 +/- 0.7	750A	2.3
1998 May 12	16.5	8.9 +/- 0.5	23.9 +/- 0.7	37.1 +/- 0.8	31.4 +/- 0.7	750A	1.0
1998 May 13	17.8	11.0 +/- 0.5	25.1 +/- 0.7	32.6 +/- 0.7	26.2 +/- 0.6	6C	2.6
1998 May 15	19.7	12.1 +/- 0.6	25.3 +/- 0.7	28.6 +/- 0.6	21.6 +/- 0.5	6C	0.5
1998 May 17	21.6	12.7 +/- 0.6	20.9 +/- 0.7	24.3 +/- 0.6	18.8 +/- 0.4	6C	1.2
1998 May 19	23.6	11.8 +/- 0.6	22.9 +/- 0.7	24.7 +/- 0.6	17.6 +/- 0.4	6C	0.7
1998 May 21	25.9	16.7 +/- 0.6	28.0 +/- 0.8	27.6 +/- 0.6	20.9 +/- 0.5	6C	0.5
1998 May 22	26.8	15.8 +/- 0.6	28.7 +/- 0.8	29.5 +/- 0.7	21.7 +/- 0.5	6C	0.7
1998 May 24	28.8	19.6 +/- 0.6	31.1 +/- 0.8	30.0 +/- 0.7	22.0 +/- 0.5	6C	1.3
1998 May 25	30.0	20.0 +/- 0.6	31.3 +/- 0.8	30.0 +/- 0.7	22.1 +/- 0.5	6C	1.9
1998 May 28	32.9	23.7 +/- 0.7	34.3 +/- 0.8	30.3 +/- 0.7	21.3 +/- 0.5	750E	1.0
1998 May 30	34.7	23.9 +/- 0.7	33.5 +/- 0.8	28.6 +/- 0.6	20.2 +/- 0.5	750E	1.0
1998 Jun 01	36.9	23.5 +/- 0.7	31.8 +/- 0.8	27.0 +/- 0.6	18.4 +/- 0.4	750E	1.0
1998 Jun 03	38.8	25.2 +/- 0.7	31.0 +/- 0.8	24.6 +/- 0.6	16.1 +/- 0.4	750E	0.9
1998 Jun 04	40.0	25.9 +/- 0.7	31.3 +/- 0.8	24.1 +/- 0.6	16.6 +/- 0.4	750E	0.7
1998 Jun 10	45.7	28.9 +/- 0.8	26.8 +/- 0.7	20.7 +/- 0.5	13.2 +/- 0.3	750E	1.1
1998 Jun 16	51.7	25.8 +/- 0.7	23.1 +/- 0.7	16.3 +/- 0.4	10.5 +/- 0.3	750E	1.9
1998 Jun 22	57.7	19.7 +/- 0.6	18.5 +/- 0.6	14.0 +/- 0.4	8.1 +/- 0.3	750E	2.9
1998 Jun 29	64.7	17.4 +/- 0.6	15.6 +/- 0.6	11.4 +/- 0.4	7.7 +/- 0.3	750E	3.8
1998 Jul 02	67.7	17.4 +/- 0.6	15.6 +/- 0.6	11.1 +/- 0.4	7.2 +/- 0.2	750E	2.3
1998 Jul 15	80.5	13.0 +/- 0.6	9.6 +/- 0.5	6.3 +/- 0.3	4.1 +/- 0.2	750E	1.7
1998 Jul 22	87.7	11.0 +/- 0.5	8.2 +/- 0.5	5.0 +/- 0.3	3.3 +/- 0.2	750E	4.9
1998 Jul 28	93.4	11.3 +/- 0.5	7.3 +/- 0.5	4.0 +/- 0.3	2.2 +/- 0.2	750E	1.6
1998 Aug 06	102.8	7.7 +/- 0.5	6.3 +/- 0.5	4.3 +/- 0.3	2.7 +/- 0.2	750E	1.9
1998 Aug 18	114.8	8.2 +/- 0.5	5.7 +/- 0.5	3.2 +/- 0.3	1.9 +/- 0.2	6C	2.7
1998 Aug 30	129.8	7.7 +/- 0.5	5.3 +/- 0.5	3.4 +/- 0.3	2.0 +/- 0.2	6C	1.6
1998 Sep 22	149.5	5.4 +/- 0.5	3.8 +/- 0.5	2.5 +/- 0.3	1.5 +/- 0.2	6C	1.3
1998 Nov 04	192.4	7.3 +/- 0.5	4.7 +/- 0.5	3.1 +/- 0.3	1.9 +/- 0.2	6D	2.3
1998 Dec 30	249.2	2.4 +/- 0.5	1.6 +/- 0.5	1.1 +/- 0.3	0.7 +/- 0.2	375	2.7
1999 Mar 11	320	0.9 +/- 0.2	0.9 +/- 0.2	0.4 +/- 0.2	0.4 +/- 0.2	1.5B	1.8
2000 Jun 24	790	0.7 +/- 0.2 (?)	<0.2 +/- 0.1	<0.2 +/- 0.1	<0.2 +/- 0.1	6B	3.3

Notes: All but the first three observation were made pointing at SN1998bw (RA 19:35:03.32, Dec -52:50:44.8). The first observation pointed at NFI source 1 (RA 19:35:04, Dec -52:48:34), the 2nd and 3rd at NFI source 2 (RA 19:35:21, Dec -52:52:19). The Day value in column 2 is the elapsed time since the GRB (April 25.909) for the midpoint of the observation.

Observations on 98:04:28 - Day 3

Two observations of two hours each, spaced by 6 hours. The observing times were from 98APR28:17:30 to 98APR28:19:30 and 98APR28:23:30 to 98APR29:01:30. Total integration is 3.1 hours at 6cm (4800 MHz) and 3cm (8640 MHz). The array is in a less than optimal configuration (750A) and antenna 3 was not available during this run. The fieldcenter coincides with the center of the first BeppoSAX 1' error circle (RA 19:35:04, Dec -52:48:34). The primary beam FWHM is 10' and 5' respectively.

The 6cm image has an rms of 0.09 mJy. There are 3 sources above 10 sigma, one within the 1' error radius. Here's a list with three 10 sigma detections in a 5'x5' box. There are no detections within the latest BeppoSAX error circle for the transient source at RA 19:35:21, Dec -52:52:19.
The 3cm image has an rms of 0.08 mJy. There are 2 sources above 10 sigma, one within the 1' error radius. Here's a list with two 10 sigma detections in a 5'x5' box. The BeppoSAX transient position is too far from the field center to give a useful result.
Fluxdensities for the SN candidate at (RA 19:35:03.31 Dec -52:50:44.7) are 13 mJy at 3cm and 9 mJy at 6cm.

Observations on 98:04:29 - Day 4

Observations at the BeppoSAX transient position were made from 98APR29:19:01 to 98APR29:20:00 and 98APR30:00:33 to 98APR30:02:05. Total integration is 2.2 hours at 6cm (4800 MHz) and 3cm (8640 MHz) in the 750A configuration (all 6 antennas operating).

The 6cm image has an rms of 0.11 mJy. There are no detections within 5'x5' from the fieldcenter.
The 3cm image has an rms of 0.09 mJy. There are no detections within 5'x5' from the fieldcenter.
However, the brightest source in the field at both 3 and 6 cm (RA 19:35:03.31 Dec -52:50:44.7) coincides with a recent SN candidate discovered in the early barred spiral ESO 184-G82. Flux densities are 13 mJy at 3cm and 9.9 mJy at 6cm.

Observations on 98:05:05 - Day 10

Observations at the BeppoSAX transient position (NFI source 1SAXJ1935.3-5252, RA 19:35:21, Dec -52:52:19) were made from 98MAY05:13:15 to 98MAY06:01:02. Total integration was 8.8 hours at 6cm (4800 MHz) and 3cm (8640 MHz) in the 750A configuration (all 6 antennas operating except for CA04 in the last hour).

However, the SN candidate in ESO 184-G82 has brightened considerably

The 6cm image has an rms of 0.05 mJy. Here's a list with four 15 sigma detections .
The 3cm image has an rms of 0.05 mJy. Here's a list with two 15 sigma detections .
The SN candidate at (RA 19:35:03.31 Dec -52:50:44.7) now has a fluxdensity (corrected for primary beam attenuation) of 48 mJy at 3cm and 39 mJy at 6cm.

Observations on 98:05:07 - Day 12

Today observations were made at the position of the SN candidate at (RA 19:35:03.32, Dec -52:50:44.8) from 98MAY07:11:36 to 98MAY07:18:55. Total integration was 2.6 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 750A configuration using all 6 antennas.
The SN candidate was detected at all frequencies and had a fluxdensity of 5, 20, 45, 49 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:10 - Day 15

Observations were made at the position of the SN candidate at (RA 19:35:03.32, Dec -52:50:44.8) from 98MAY10:11:38 to 98MAY10:15:00. Total integration was 1.6 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 750A configuration using all 6 antennas.
The SN candidate was detected at all frequencies and had a fluxdensity of 7, 21, 40, 37 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:11 - Day 16

Observations were made at the position of the SN candidate at (RA 19:35:03.32, Dec -52:50:44.8) from 98MAY11:11:21 to 98MAY11:18:00. Total integration was 2.3 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 750A configuration using all 6 antennas.
The SN candidate was detected at all frequencies and had a fluxdensity of 7, 24, 38, 34 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:12 - Day 17

Observations were made at the position of the SN candidate at (RA 19:35:03.32, Dec -52:50:44.8) from 98MAY12:11:06 to 98MAY12:13:59. Total integration was ~1 hour at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 750A configuration using all 6 antennas.
The SN was detected at all frequencies and had a fluxdensity of 7, 24, 36, 28 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:13 - Day 18

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) from 98MAY13:15:14 to 98MAY13:22:56. Total integration was 2.6 hour at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 5 antennas in the 6C configuration.
The SN was detected at all frequencies and had a fluxdensity of 10, 24, 34, 27 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:15 - Day 20

Two short observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) at 98MAY15:13:21 and 98MAY15:19:13. Total integration was 0.5 hour at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using all antennas in the 6C configuration.
The SN was detected at all frequencies and had a fluxdensity of 11, 23, 25, 19 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:17 - Day 22

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) from 98MAY17:11:10 to 98MAY17:19:13. Total integration was 1.15 hour at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 5 to 6 antennas in the 6C configuration.
The SN was detected at all frequencies and had a fluxdensity of 13, 20, 23, 18 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:19 - Day 24

Three short observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) from 98MAY19:11:52 to 98MAY19:18:58. Total integration was 0.7 hour at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 6 antennas in the 6C configuration.
The SN was detected at all frequencies and had a fluxdensity of 12, 22, 24, 18 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:21 - Day 26

Two short observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98MAY21:17:33 and 98MAY22:00:05. Total integration was 0.45 hour at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 6 antennas in the 6C configuration.
The SN was detected at all frequencies and had a fluxdensity of 16, 26, 25 and 18.5 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:22 - Day 27

Three short observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98MAY22:12:27 and 98MAY22:23:50. Total integration was 0.71 hour at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 6 antennas in the 6C configuration.
The SN was detected at all frequencies and had a fluxdensity of 16, 27, 29 and 22 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:24 - Day 29

Three observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98MAY24:12:37 and 98MAY25:00:01. Total integration was 1.3 hour at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 6 antennas in the 6C configuration.
The SN was detected at all frequencies and had a fluxdensity of 20, 32, 30 and 22 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:25 - Day 30

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98MAY25:17:19 and 98MAY26:00:24. Total integration was 1.9 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 6 antennas in the 6C configuration.
The SN was detected at all frequencies and had a fluxdensity of 19, 32, 30 and 22.5 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:28 - Day 33

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98MAY28:16:15 and 98MAY28:22:21. Total integration was 0.95 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 6 antennas in the 750E configuration. Note that the 20cm fluxes are rather uncertain for short observations in this configuration due to confusion and limited uv-coverage (+/- 3 mJy).
The SN was detected at all frequencies and had a fluxdensity of 19, 25, 29 and 21 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:05:30 - Day 35

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98MAY30:11:46 and 98MAY30:18:30. Total integration was 0.95 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 6 antennas in the 750E configuration.
The SN was detected at all frequencies and had a fluxdensity of 24, 32, 27 and 17 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:06:01 - Day 37

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98JUN01:13:47 and 98JUN01:22:46. Total integration was 0.97 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 6 antennas in the 750E configuration.
The SN was detected at all frequencies and had a fluxdensity of 19, 30, 26 and 16 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:06:03 - Day 39

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98JUN03:10:21 and 98JUN03:22:17. Total integration was 0.85 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 6 antennas in the 750E configuration.
The SN was detected at all frequencies and had a fluxdensity of 25, 30, 24 and 17 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:06:04 - Day 40

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98JUN04:19:19 and 98JUN05:00:11. Total integration was 0.65 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 6 antennas in the 750E configuration.
The SN was detected at all frequencies and had a fluxdensity of 21, 29, 22 and 15 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:06:10 - Day 46

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98JUN10:09:05 and 98JUN10:17:34. Total integration was 1.1 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 6 antennas in the 750E configuration.
The SN was detected at all frequencies and had a fluxdensity of 23, 26, 19 and 12 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:06:16 - Day 52

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98JUN16:09:50 and 98JUN16:20:25. Total integration was 1.9 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) using 5 antennas in the 750E configuration (CA01 missing).
The SN was detected at all frequencies and had a fluxdensity of 25, 22, 17 and 10 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:06:22 - Day 58

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98JUN22:09:51 and 98JUN22:20:33. Total integration was 2.9 hours at 20cm (1384 MHz), 13cm (2496 MHz), and 1.5 hours at 6cm (4800 MHz) and 3cm (8640 MHz) in the 750E configuration (CA01 missing at 13cm).
The SN was detected at all frequencies and had a fluxdensity of 19, 17, 13 and 7.5 mJy at 20, 13, 6, and 3cm respectively.
Images: 20cm , 13cm , 6cm , 3cm
Source lists: 20cm , 13cm , 6cm , 3cm

Observations on 98:06:29 - Day 65

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98JUN29:08:16 and 98JUN29:20:35. Total integration was 3.8 hours at 20cm (1384 MHz), 13cm (2496 MHz), and 4.0 hours at 6cm (4800 MHz) and 3cm (8640 MHz) in the 750E configuration.
The SN was detected at all frequencies and had a fluxdensity of 17.4, 15.6, 11.1 and 7.2 mJy at 20, 13, 6, and 3cm respectively.

Observations on 98:07:02 - Day 68

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98JUL02:08:43 and 98JUL02:19:26. Total integration was 2.3 hours at 20cm (1384 MHz), 13cm (2496 MHz), and 2.8 hours at 6cm (4800 MHz) and 3cm (8640 MHz) in the 750E configuration.
The SN was detected at all frequencies and had a fluxdensity of 17.4, 15.6, 11.4 and 7.7 mJy at 20, 13, 6, and 3cm respectively.

Observations on 98:07:15 - Day 81

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98JUL15:06:51 and 98JUL15:14:44. Total integration was 1.7 hours at 20cm (1384 MHz), 13cm (2496 MHz), and 1.9 hours at 6cm (4800 MHz) and 3cm (8640 MHz) in the 750E configuration.
The SN was detected at all frequencies and had a fluxdensity of 13.0, 9.6, 6.3 and 4.1 mJy at 20, 13, 6, and 3cm respectively.

Observations on 98:07:22 - Day 88

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98JUL22:06:54 and 98JUL22:20:50. Total integration was 4.9 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 750E configuration.
The SN was detected at all frequencies and had a fluxdensity of 11.0, 8.2, 5.0 and 3.3 mJy at 20, 13, 6, and 3cm respectively.

Observations on 98:07:28 - Day 94

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98JUL28:06:00 and 98JUL28:10:33. Total integration was 1.6 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 750E configuration.
The SN was detected at all frequencies and had a fluxdensity of 11.3, 7.3, 4.0 and 2.2 mJy at 20, 13, 6, and 3cm respectively.

Observations on 98:08:06 - Day 103

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98AUG06:14:46 and 98AUG06:20:03. Total integration was 1.9 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 750E configuration.
The SN was detected at all frequencies and had a fluxdensity of 7.7, 6.3, 4.3 and 2.7 mJy at 20, 13, 6, and 3cm respectively.

Observations on 98:08:18 - Day 115

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98AUG18:04:18 and 98AUG18:12:09. Total integration was 2.7 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 6C configuration.
The SN was detected at all frequencies and had a fluxdensity of 8.2, 5.7, 3.2 and 1.9 mJy at 20, 13, 6, and 3cm respectively.

Observations on 98:08:30 - Day 127

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98AUG30:06:01 and 98AUG30:11:02. Total integration was 1.6 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 6C configuration.
The SN was detected at all frequencies and had a fluxdensity of 7.7, 5.3, 3.4 and 2.0 mJy at 20, 13, 6, and 3cm respectively.

Observations on 98:09:23 - Day 150

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98SEP22:06:34 and 98SEP22:16:56. Total integration was 1.3 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 6C configuration.
The SN was detected at all frequencies and had a fluxdensity of 5.4, 3.8, 2.5 and 1.5 mJy at 20, 13, 6, and 3cm respectively.

Observations on 98:11:04 - Day 193

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98NOV04:01:35 and 98NOV04:11:19. Total integration was 2.3 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 6D configuration.
The SN was detected at all frequencies and had a fluxdensity of 7.3, 4.7, 3.1 and 1.9 mJy at 20, 13, 6, and 3cm respectively.

Observations on 98:12:30 - Day 249

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 98DEC29:21:10 and 98DEC30:07:02. Total integration was 2.7 hours at 20cm (1384 MHz), 13cm (2496 MHz), 6cm (4800 MHz) and 3cm (8640 MHz) in the 375m configuration.
The SN was detected at all frequencies and had a fluxdensity of 2.4, 1.6, 1.1 and 0.7 mJy at 20, 13, 6, and 3cm respectively.

Observations on 99:03:11 - Day 320

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 99MAR11:15:45 and 99MAR12:02:13. Total integration was 1.7 hours at 20cm (1384 MHz) and 13cm (2496 MHz) and 1.9 hours at 6cm (4800 MHz) and 3cm (8640 MHz) in the 1.5B configuration.
The SN was detected at all frequencies and had a fluxdensity of 0.9, 0.9, 0.4 and 0.4 mJy at 20, 13, 6, and 3cm respectively, the 6 and 3cm detections are marginal and could be affected by dc-offset terms.

Observations on 2000:06:24 - Day 790

Observations were made at the position of SN1988bw (RA 19:35:03.32, Dec -52:50:44.8) between 00JUN23:08:12 and 00JUN24:16:58. Total integration was 3.2 hours at 20cm (1384 MHz) and 13cm (2496 MHz) and 3.5 hours at 6cm (4800 MHz) and 3cm (8640 MHz) in the 6B configuration.
The SN was possibly detected at 20cm, 0.7+/-0.2 mJy, upper limit is around 0.2 mJy (2 sigma) at the other bands. The 20cm detection could be affected by dc offset terms.

This work has been reported in GCN63, IAUC6896, GCN71, IAUC6903, astro-ph/9807001, Kulkarni et al, 1998, Nature 395, 663 and Wieringa, M. H.; Kulkarni, S. R.; Frail, D. A., 1999, A&AS 138, 467.

Last changed on: 28-JUN-2000

Mark.Wieringa@csiro.au