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GCN Circular 3748

GRB050803: Swift-BAT detection of a very long burst
2005-08-03T20:10:23Z (19 years ago)
Scott Barthelmy at NASA/GSFC <>
D.L. Band (GSFC-UMBC), S. Barthelmy (GSFC), P. Boyd (GSFC-UMBC), P. Brown (PSU),   
D. Burrows (PSU), M. Chester (PSU), J. Cummings (GSFC/NRC), N. Gehrels (GSFC),     
C. Markwardt (GSFC), J. Nousek (PSU), K. Page (U. Leicester), C. Pagani (PSU),     
D. Palmer (LANL), T. Sakamoto (GSFC), J. Racusin (PSU)                             
on behalf of the Swift team:                                                       
At 19:14:00 UT, Swift-BAT triggered and located GRB050803 (trigger=148833).        
The spacecraft slewed immediately.  The BAT on-board calculated location           
is RA,Dec 350.650d,+5.800d {23h 22m 36s,+05d 48' 00"} (J2000), with an             
uncertainty of 3 arcmin (radius, 90% containment, stat+sys).  The BAT light        
curve shows a multi-peak structure with a total duration of at least 150 sec.      
There is a fairly strong short peak at T+145 sec.  The peak count rate was         
~1000 counts/sec (15-350 keV), at ~80 seconds after the trigger.                   
The XRT began observing at 19:16:31.6 UT, 151.6 seconds after the BAT trigger.     
An uncatalogued, rapidly fading X-ray source was detected at an RA and Dec of      
23h 22m 37.7s, 05d 47m 7.4s (J2000; 90% containment uncertainty of 6 arcsec),      
which is 58.4" from the BAT position.                                              
The UVOT began settled exposures about 3 minutes after the burst.  Using a         
preliminary ground-processed 100-sec image, the upper limit is 18.5 (3 sigma)      
in the V band.
We are currently in the portion of the orbits where the spacecraft does not        
pass over the Malindi downlink station.  Therefore, it will be ~4 hours            
before we have access to the full data set for the refined analyses.
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