TITLE:   GCN CIRCULAR
NUMBER:  11793
SUBJECT: GRB 110315A: Swift-BAT refined analysis
DATE:    11/03/16 13:47:11 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), C. B. Markwardt (GSFC),
A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
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 110315A (trigger #449399)
(Melandri, et al., GCN Circ. 11790).  The BAT ground-calculated position is
RA, Dec = 279.205, 17.537 deg which is 
   RA(J2000)  =  18h 36m 49.2s 
   Dec(J2000) = +17d 32' 13.9" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 57%.
 
The mask-weighted light curve shows a multi-peak structure starting 
at ~T-70 sec, with several peaks of approximate equal brightness
at T-21, T-3, T+3, and T+17 sec, and then returning to background
at ~T+90 sec.  There is weak emission (~2 sigma) in the BAT 15-25 keV band
starting at ~T+440 out to ~T+580 sec.  This is likley associated with the flare
in the XRT lightcurve at ~T+500 sec.  T90 (15-350 keV) is 77 +- 12 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-66.8 to T+38.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.77 +- 0.08.  The fluence in the 15-150 keV band is 4.1 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+3.13 sec in the 15-150 keV band
is 1.7 +- 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/449399/BA/