[vsnet-grb-info 2951] GRB 060219: Swift-BAT detection of a weak burst

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4788
SUBJECT: GRB 060219: Swift-BAT detection of a weak burst
DATE:    06/02/19 23:14:53 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <Scott at lheamail.gsfc.nasa.gov>

A. Moretti (OAB/INAF), S. Barthelmy (GSFC), D. Burrows (PSU),
J. Cummings (GSFC/ORAU), N. Gehrels (GSFC), S. Hunsberger (PSU),
C. Markwardt (GSFC/UMD), F. Marshall (GSFC), D. Palmer (LANL),
T. Sakamoto (GSFC/ORAU)
on behalf of the Swift team:

At 22:48:05 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 060219 (trigger=191512).  Swift slewed immediately to the burst.
The BAT on-board calculated location is RA,Dec 241.806,+32.330 deg
{16h 07m 14s, +32d 19' 49"} (J2000) with an uncertainty of 3 arcmin
(radius, 90% containment, including systematic uncertainty).  The BAT
light curve shows a weak single peak with a duration of ~10 sec.
The peak count rate was ~500 counts/sec (15-350 keV), at ~5 sec
after the trigger.

The XRT began taking data at 22:50:05 UT, 120 seconds after the BAT trigger.
The XRT on-board centroid algorithm did not find a source in the image and
no prompt position is available.  The prompt spectrum and lightcurve
are consistent with a weak, possibly fading source in the field of view.
We are waiting for down-linked data to detect and determine a position
for the source.

UVOT took a finding chart exposure of 200 seconds with the V filter starting
121 seconds after the BAT trigger.  No afterglow candidate has been found
in the initial data products.  The 2.7'x2.7' sub-image covers 25% of the
BAT error circle.  The typical 3-sigma upper limit has been about 18th mag.
The 8'x8' region for the list of sources generated on-board covers 100%
of the BAT error circle.  The list of sources is typically complete
to about 18.0 mag.  No correction has been made for the expected extinction
of about 0.1 magnitudes.