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GCN Circular 5365

GRB 060729: Swift detection of a burst with an UVOT optical counterpart
2006-07-29T19:53:56Z (18 years ago)
Scott Barthelmy at NASA/GSFC <>
D. Grupe (PSU), L. M. Barbier (NASA/GSFC), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), M. M. Chester (PSU),
C. Guidorzi (Univ Bicocca&INAF-OAB), J. A. Kennea (PSU),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), J. L. Racusin (PSU)
and M. Stamatikos (NASA/ORAU) report on behalf of the Swift Team:

At 19:12:29 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 060729 (trigger=221755).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is RA,Dec 95.338, -62.345
{06h 21m 21s, -62d 20' 41"} (J2000) with an uncertainty of 3 arcmin
(radius, 90% containment, including systematic uncertainty). 
The BAT light curve shows a small peak at T_zero of ~5 sec duration
and a possible much larger peak starting at ~T+70 until ~T+120. 
The peak count rate was ~2000 counts/sec (15-350 keV),
at ~T+90 sec after the trigger. 

The XRT began observing the field at 19:14:33 UT, 124 seconds after the
BAT trigger. XRT found a bright, fading, uncatalogued X-ray source
located at RA(J2000) = 06h 21m 31.3s, Dec(J2000) = -62d 22' 13.4", with an
estimated uncertainty of 4.7 arcseconds (90% confidence radius). 
This location is 116 arcseconds from the BAT on-board position, within
the BAT error circle. The initial flux in the 0.1s image was
7.7e-08 erg/cm2/s (0.2-10 keV). 

UVOT began observing in the White filter at 19:14:43.95 UT, 134.7 sec
after the BAT trigger. An uncataloged source is detected at RA, DEC =
95.3827, -62.3702, 3.2 arcsecs from ground-determined XRT position,
which brightens from 19.2 to 17.8 in the second White image. The
magnitudes have not been corrected for galactic absorption in this
direction, E(B-V) = 0.054. 

We are currently in the Malindi gap so we will not have the full data set
for this burst for another 7 hours.
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