[vsnet-grb-info 12817] GRB 130131B: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14164
SUBJECT: GRB 130131B: Swift-BAT refined analysis
DATE:    13/01/31 23:16:16 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

T. Sakamoto (AGU), 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), A. Lien (GSFC/ORAU), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), G. Sato (ISAS), M. H. Siegel (PSU),
M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-119 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 130131B (trigger #547420)
(Siegel, et al., GCN Circ. 14159).  The BAT ground-calculated position is
RA, Dec = 173.957, 15.033 deg which is 
   RA(J2000)  =  11h 35m 49.6s 
   Dec(J2000) = +15d 01' 59.3" 
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 51%.
 
The mask-weighted light curve shows a single pulse starting at ~T-1 sec,
peaking at ~T+0.5 sec, and ending at ~T+10 sec.  T90 (15-350 keV) is
4.30 +- 0.26 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.28 to T+4.37 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.15 +- 0.20.  The fluence in the 15-150 keV band is 3.4 +- 0.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.28 sec in the 15-150 keV band
is 1.0 +- 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/547420/BA/