[vsnet-grb-info 4665] GRB 070518, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6417
SUBJECT: GRB 070518, Swift-BAT refined analysis
DATE:    07/05/18 21:36:24 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

H. Krimm (GSFC/USRA), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
C. Guidorzi (Univ Bicocca&INAF-OAB), C. Markwardt (GSFC/UMD),
D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU),
G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
 
Using the data set from T-119 to T+183 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 070518 (trigger #279592)
(Guidorzi, et al., GCN Circ. 6415).  The BAT ground-calculated position is
RA, Dec = 254.221, 55.285 deg  which is 
   RA(J2000)  = 16h 56m 52.9s 
   Dec(J2000) = 55d 17'  5.6" 
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 84%.
 
The mask-weighted lightcurves shows a single peak starting a ~T-5 sec
and ending at ~T+10 sec.  T90 (15-350 keV) is 5.5 +- 0.2 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-1.8 to T+4.5 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.11 +- 0.25.  The fluence in the 15-150 keV band is 1.6 +- 0.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.12 sec in the 15-150 keV band
is 0.7 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.