GCN Circular 2987

G. Sato (ISAS), P. Boyd (GSFC-UMBC), S. Barthelmy, 
L. Barbier (GSFC), J. Cummings (GSFC), E. Fenimore (LANL),
N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), C. Milvia (ASDC), K. McLean (LANL), 
J. Nousek (PSU), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC), M. Suzuki (Saitama), J. Tueller (GSFC)  
on behalf of the Swift-BAT team:

At 12:00:53 UT, the Swift Burst Alert Telescope (BAT) triggered and
located on-board GRB050126.  The spacecraft autonomously slewed to the
burst and was detected by Swift/XRT as well (Kinnea et al., GCN #2984).

The burst is a FRED-type single broad peak, with a rapid rise (~1 sec)
and total duration ~30 seconds (T50 = 14 sec, T90 = 26 sec).  The
total fluence is 1.1e-6 erg/cm2 (15-350 keV), and the peak five second
flux is 0.4 ph/cm2/sec (15-350 keV).  The spectrum is consistent with
a power law with photon index 1.3 +/- 0.1 in the 20-150 keV band.

The spacecraft slew occurred between times 12:01:41 and 12:02:32 UT,
with a subsequent settling period until 12:03:02 UT.  From 12:02:32
onward, there is no detectable gamma ray emission with an approximate
2 sigma upper limit of 7e-9 erg/cm2/s (15-350 keV) based on the above
spectrum.

The BAT ground-derived position is RA,Dec = 278.111, 42.384 (J2000)
with an estimated uncertainty of 4 arcmin (radius, 3-sigma, including
a systematic uncertainty).  This is within 62 arcsec of the XRT
position (GCN #2984), and within 22 arcsec of the BAT on-board derived
position.