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GCN Circular 50

GRB980329 sub-millimeter observations
1998-04-07T18:02:12Z (26 years ago)
Ian Smith at Rice U <>
I. A. Smith (Rice University) and R. P. J. Tilanus (Joint Astronomy Centre) 
report on behalf of the James Clerk Maxwell Telescope (JCMT) GRB collaboration:
We used the SCUBA sub-millimeter continuum bolometer array on the JCMT to 
observe the variable radio source VLA J0702+3850 proposed by Taylor et al. 
(GCN #40) as the radio afterglow to GRB 980329.
On UT 1998 April 5.2 we detected a source at 850 microns with a preliminary 
flux density of 5 +/- 1.5 mJy.  This source was confirmed on April 6.2 with 
a flux density of 4 +/- 1.2 mJy, resulting in an average of 4.5 +/- 1 mJy 
over the two days.  The 850 micron source is present in all our separate 
integrations making us confident it is real.  A hint of a fading trend 
appears to be confirmed by observations on April 7.2 when the (preliminary)
850 micron flux density was 2 +/- 0.8 mJy. 

The source was not detected at 450 microns with a preliminary rms of 10.0 
mJy averaged over the first two days.

Assuming these fluxes are due to the burst counterpart, they should represent
"clean" measures of its intensity, unaffected by scintillation and extinction.  
Monitoring with SCUBA is continuing.

We wish to thank Dr. L. Avery and Dr. J. MacLeod for their cooperation and
valuable help in obtaining these observations, and Dr. G. Watt and Dr. I. 
Robson for rapidly scheduling the observations.

This report may be cited in publications.
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