GCN Circular 14315

S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), P. A. Evans (U Leicester) N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), 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 130315A (trigger #551126)
(Evans, et al., GCN Circ. 14311
Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 157.541, -51.794 deg which is
    RA(J2000)  =  10h 30m 09.9s
    Dec(J2000) = -51d 47' 37.4"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 42%.

The mask-weighted light curve shows two broad peaks, the first starting at
~T-10 sec, peaking at T+10 sec and then slowly declining until ~T+70 sec.  The
rise to the second peak begins almost immediately, with a broad peak around
T+160 sec and falling to background by T+240 sec. Note that a slew took the
source out of the field of view at ~T+650 sec. T90 (15-350 keV) is
233.4 +- 17.5 sec (estimated error including systematics).

The time-averaged spectrum from T-3.30 to T+268.00 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.81 +- 0.08.  The fluence in the 15-150 keV band is 4.9 +- 0.2 x 10^-6 erg/cm2. 
The 1-sec peak photon flux measured from T+8.41 sec in the 15-150 keV band is 
1.0 +- 0.2 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/551126/BA/