TITLE:   GCN CIRCULAR
NUMBER:  20433
SUBJECT: GRB 170111A: Swift-BAT refined analysis
DATE:    17/01/11 21:41:56 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester),

J. R. Cummings (CPI), N. Gehrels (GSFC), A. Y. Lien (GSFC/UMBC),

C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+739 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170111A (trigger #731887) (Beardmore, et al., GCN Circ. 20423). The BAT ground-calculated position is RA, Dec = 20.688, -32.541 deg which is RA(J2000) = 01h 22m 45.2s Dec(J2000) = -32d 32' 28.4" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 46%. The mask-weighted light curve shows a single, triangular shaped peak beginning at

T-20 sec, peaking at T+0 sec and ending at about T+10 sec. T90 (15-350 keV) is

29.9 +- 9.4 sec (estimated error including systematics).


The time-averaged spectrum from T-13.59 to T+25.32 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.64 +- 0.21.  The fluence in the 15-150 keV band is 8.1 +- 1.1 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+2.09 sec in the 15-150 keV band
is 0.9 +- 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/731887/BA/