[vsnet-grb-info 9900] GRB 101020A, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11358
SUBJECT: GRB 101020A, Swift-BAT refined analysis 
DATE:    10/10/21 13:36:55 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.krimm at nasa.gov>

T. Sakamoto (GSFC/UMBC), 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), D. M. Palmer (LANL),
G. Sato (ISAS), C. J. Saxton (UCL-MSSL), M. Stamatikos (OSU),
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 Swift/BAT GRB 101020A (trigger #436737)
(Saxton, et al., GCN Circ. 11357).  The BAT ground-calculated position is
RA, Dec = 189.607, 23.129 deg which is
    RA(J2000)  =  12h 38m 25.8s
    Dec(J2000) = +23d 07' 44.1"
with an uncertainty of 3.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 42%.

The mask-weighted light curve shows a very broad peak with no obvious features,
extending roughly from T-50 sec to T+150 sec.  Most of the emission is below 50 
keV.  A pre-planned slew took the burst out of the field of view at about T+230 
sec.  T90 (15-350 keV) is 175.0 +- 28. sec (estimated error including systematics).

The time-averaged spectrum from T-50.0 to T+159.0 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.04 +- 0.17.  The fluence in the 15-150 keV band is 2.6 +- 0.3 x 10^-06 
erg/cm^2. The 1-sec peak photon flux measured from T+19.00 sec in the 15-150 keV 
band is 0.5 +- 0.2 ph/cm^2/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/436737/BA/