TITLE:   GCN CIRCULAR
NUMBER:  13880
SUBJECT: GRB 121017A: Swift-BAT refined analysis
DATE:    12/10/18 02:26:15 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
D. Grupe (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS),
M. Stamatikos (OSU), J. Tueller (GSFC)
(i.e. the Swift-BAT team):
 
Using the data set from T-61 to T+242 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 121017A (trigger #536172)
(Grupe, et al., GCN Circ. 13875).  The BAT ground-calculated position is
RA, Dec = 288.820, -1.602 deg, which is 
   RA(J2000)  =  19h 15m 16.8s 
   Dec(J2000) = -01d 36' 07.3" 
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.
 
The mask-weighted light curve a single peak starting at ~T-3 sec, peaking 
at ~T+1 sec, and ending at ~T+5 sec.  T90 (15-350 keV) is 4.2 +- 0.5 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-2.72 to T+2.53 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.74 +- 0.17.  The fluence in the 15-150 keV band is 6.6 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.31 sec in the 15-150 keV band
is 3.3 +- 0.4 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/536172/BA/