[vsnet-grb-info 2681] GRB 060115: Refined analysis of the Swift-BAT burst

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4518
SUBJECT: GRB 060115:  Refined analysis of the Swift-BAT burst
DATE:    06/01/16 00:52:07 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <Scott at lheamail.gsfc.nasa.gov>

L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC),
E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD),
K. Hurley (Berkeley), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), 
J. Norris (GSFC), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC)
on behalf of the Swift-BAT team:

Using the downloaded data set from T-300 to T+302 sec
from recent telemetry downlinks, we report further analysis
of BAT GRB 060115 (trigger #177408)  (Tagliaferri, et al., GCN 4509).
The BAT ground-calculated position is (RA,Dec) = 54.005,+17.336 deg
{03h 36m 01.1s,+17d 20' 10.5"} (J2000) +- 2.0 arcmin, (radius,
sys+stat, 90% containment).  This is 1.7 arcmin from the position 
reported by the XRT (Perri, et al. GCN 4514).  The partial coding was 85%.
 
The lightcurve consists of faint precursor peak starting at T-50 sec,
peaking around T-30sec, and merging into the second peak.
The second peak is roughly triangular in shape, starting
at T-15 sec, peaking at T+5sec, and ending at T+40 sec.  There is
a third and largest peak (also roughly triangular in shape)
starting at T+80 sec, peaking at T+95 sec, and ending at T+120 sec.
T90 (15-350 keV) is at least 142 +- 5 sec (estimated error
including systematics).
 
The power law index of the time-averaged spectrum is 1.76 +- 0.12.
The fluence in the 15-150 keV band is (1.9 +- 0.1) x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+94.71 sec in the 15-150 keV
band is (0.9 +- 0.1) ph/cm2/sec.  A cut-off power law model is
a marginally better fit to the data.  The power law index is
1.0 +/- 0.5 and Epeak is 62 (+31)(-10) keV; the total fluence is
(1.8 +/- 0.2) x 10^-6 erg/cm2 and the peak flux is (0.9 +/- 0.1) ph/cm2/sec.
All the quoted errors are at the 90% confidence level.