TITLE:   GCN CIRCULAR
NUMBER:  20471
SUBJECT: GRB 170115A: Swift-BAT refined analysis
DATE:    17/01/16 19:22:36 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),

N. Gehrels (GSFC), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), K. L. Page (U Leicester),  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+450 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170115A (trigger #733103) (Page, et al., GCN Circ. 20462). The BAT ground-calculated position is RA, Dec = 332.145, 13.750 deg which is RA(J2000) = 22h 08m 34.9s Dec(J2000) = +13d 45' 01.6" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a single FRED-shaped peak, starting at T+0,

peaking at around T+10 sec and decaying to background by around T+50 sec.  The

spacecraft entered the SAA at around T+400 seconds, so there is no data after

this time. T90 (15-350 keV) is 48.0 +- 22.6 sec (estimated error including

systematics).

The time-averaged spectrum from T-7.6 to T+40.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.45 +- 0.25.  The fluence in the 15-150 keV band is 4.7 +- 0.8 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+15.94 sec in the 15-150 keV band
is 0.2 +- 0.1 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/733103/BA/