[vsnet-grb-info 4242] GRB 070126, Swift-BAT refined analysis of a very faint burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6040
SUBJECT: GRB 070126, Swift-BAT refined analysis of a very faint burst
DATE:    07/01/26 20:25:16 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc at milkyway.gsfc.nasa.gov>

E. Fenimore (LANL), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
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), L. Vetere (PSU)
on behalf of the Swift-BAT team:
 
Using the data set from T-240 to T+500 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 070126 (trigger #257741)
(Veter, et al., GCN Circ. 6027).  The BAT ground-calculated position
is RA, Dec = 33.579, -73.532 deg which is 
   RA(J2000)  =   2h 14m 18.9s 
   Dec(J2000) = -73d 31' 54" 
with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 99%.
 
The mask-weighted lightcurve shows a broad, weak, and soft bump from 
T_zero to ~T+60 sec.  T90 (15-350 keV) is 51 +- 5 sec (estimated error
including systematics).
 
The time-averaged spectrum from T+1.0 to T+56.0 is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.9 +- 0.5.  The fluence in the 15-150 keV band is 1.6 +- 0.6 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+10.00 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 flux of this burst is at the lower limit of the 
BAT sensitivity.