GCN Circular 15302

T. Sakamoto (AGU), B. N. Barlow (High Point University),
S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL),
N. Gehrels (GSFC), J. Norris (BSU), H. A. Krimm (GSFC/USRA),
A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), G. Sato (ISAS), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):

Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 131002A (trigger #572721)
(Barlow, et al., GCN Circ. 15283
Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 253.103, 82.036 deg which is
  RA(J2000)  =  16h 52m 24.8s
  Dec(J2000) = +82d 02' 08.3"
with an uncertainty of 3.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 71%.

The mask-weighted light curve shows two peaks separated by ~45 seconds.
The first short peak starts at ~T0 and lasts for ~1 sec,  the second long peak
starts at ~T+40 and ends at ~T+60. T90 (15-350 keV) is 55.59 +- 3.98 sec
(estimated error including systematics).

The spectral lag for the first short pulse is 0.114 s +- 0.04 s (for the 50-100 keV and
15-25 keV bands), and the spectrum is slightly softer than the second long pulse.
Therefore, the spectral and timing properties match better to those of regular long bursts
than those normally seen in short bursts with extended emission.

The time-averaged spectrum from T-0.20 to T+59.67 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.63 +- 0.19.  The fluence in the 15-150 keV band is 6.4 +- 0.8 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+43.17 sec in the 15-150 keV band
is 1.3 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/572721/BA/