[vsnet-grb-info 9304] GRB 100522A, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10788
SUBJECT: GRB 100522A, Swift-BAT refined analysis
DATE:    10/05/22 13:31:13 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.a.krimm at nasa.gov>

S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
E. Troja (NASA/GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):

Using the data set from T-60 to T+243 sec from the recent telemetry 
downlink,
we report further analysis of BAT GRB 100522A (trigger #422783)
(Troja, et al., GCN Circ. 10784).  The BAT ground-calculated position is
RA, Dec = 6.990, +9.397 deg which is
   RA(J2000)  =  00h 27m 57.6s
   Dec(J2000) = +09d 23' 50.1"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 71%.

The mask-weighted light curve shows a complex structure.  There are two 
main
episodes of emission, starting at T-0.5 sec and T+25 sec, respectively.  
The
first episode starts with a broad multi-peaked structure 2.5 sec long 
followed
by three short (~0.3 sec long) peaks.  Then the emission returns to
background levels before rising in a second, less intense and softer two 
peak
structure approximately 15 sec long. T90 (15-350 keV) is 35.3 +- 1.8 sec
(estimated error including systematics).

The time-averaged spectrum from T-0.5 to T+40.2 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.89 +- 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+0.04 sec in the 15-150 keV band
is 7.1 +- 0.3 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/422783/BA/