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GCN Circular 17213

Subject

GRB 141221A: Swift-BAT refined analysis

Date

2014-12-21T19:28:45Z (10 years ago)

From

Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), E. Sonbas (NASA/GSFC/Adiyaman Univ.), 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 141221A (trigger #622006)
(Sonbas, et al., GCN Circ. 17206Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 198.283, 8.197 deg, which is 
   RA(J2000)  =  13h 13m 07.9s 
   Dec(J2000) = +08d 11' 49.8" 
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 78%.
 
The mask-weighted light curve shows some low-level precursor emission
starting at ~T-23 sec with the first peak starting at ~T-3 sec, peaking
at ~T+1 sec, and the second peak peaking at ~T+14 sec, and ending at T+35 sec.
T90 (15-350 keV) is 36.9 +- 4.0 sec (estimated error including systematics).
 
The time-averaged spectrum from T-24.11 to T+20.33 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.74 +- 0.08.  The fluence in the 15-150 keV band is 2.1 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.10 sec in the 15-150 keV band
is 3.1 +- 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/622006/BA/