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GCN Circular 13450

Subject

GRB 120711B: Swift-BAT refined analysis

Date

2012-07-11T22:05:20Z (12 years ago)

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), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), M. J. Page (UCL-MSSL), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC)
(i.e. the Swift-BAT team):
 
Using the data set from T-141 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 120711B (trigger #526270)
(Page, et al., GCN Circ. 13431Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 331.710, 59.996 deg, which is 
   RA(J2000)  =  22h 06m 50.5s 
   Dec(J2000) = +59d 59' 46.0" 
with an uncertainty of 3.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 80%.
 
The mask-weighted light curve shows the emission starting ~T-100 sec, 
peaking at ~T+20 sec, and slowly decaying out to T+875 sec.
T90 (15-350 keV) is 60 +- 19 sec (estimated error including systematics).
 
The time-averaged spectrum from T-12.1 to T+51.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.75 +- 0.32.  The fluence in the 15-150 keV band is 5.6 +- 1.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+13.11 sec in the 15-150 keV band
is 0.4 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 

Contrary to our GCN 13431Not found
 
 
, we now think that this trigger is very likely GRB,
and not a new Galactic source.
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/526270/BA/