GCN Circular 5047

V. La Parola (INAF-IASFPA), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
P. Romano (INAF-OAB), T. Sakamoto (NASA/ORAU), E. Troja (INAF-IASFPA)
and D. E. Vanden Berk (PSU) report on behalf of the Swift Team:

At 03:03:32 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 060502 (trigger=208169).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is RA,Dec 240.858, +66.595
{16h 03m 26s, +66d 35' 42"} (J2000) with an uncertainty of 3 arcmin
(radius, 90% containment, including systematic uncertainty).  The BAT light
curve shows a roughly triangular shaped single peak starting at ~T-8 sec
and lasting until ~T+20 sec.  The peak count rate was ~2500 counts/sec
(15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 03:04:48 UT, 76 seconds after the
BAT trigger. Ground analysis of the initial XRT data found a bright,
uncatalogued, fading X-ray source located at RA(J2000) = 16h 03m
42.9s, Dec(J2000) = +66d 35' 57.4", with an estimated uncertainty of
3.9 arcseconds (90% confidence radius). This location is 98
arcseconds from the BAT on-board position, within the BAT error
circle. The initial flux in the 2.5s image was 1.3e-09 erg/cm2/s
(0.2-10 keV). 

UVOT took a finding chart exposure of 100 seconds with the White
(160-650 nm) filter starting 85 seconds after the BAT trigger.  There
is an 18.4 magnitude source that is not visible in the Digitized Sky
Survey images, at J2000 coordinate 16h 03m 42.48s, +66d 36' 02.5" 
(240.9270, +66.6007).  The position is 5.7 arcseconds from the center
of the XRT error circle. 

This burst triggered BAT at the beginning of a Malindi telemetry
downlink session and so the downlink of the TDRSS notices was delayed
until the end of the pass (~18 min).