[vsnet-grb-info 13287] GRB 130511A, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14624
SUBJECT: GRB 130511A, Swift-BAT refined analysis
DATE:    13/05/11 21:27:10 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.a.krimm at nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU),T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+950 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 130511A (trigger #555600)
(Krimm, et al., GCN Circ. 14620).  The BAT ground-calculated position is
RA, Dec = 196.654, 18.709 deg which is
    RA(J2000)  =  13h 06m 36.9s
    Dec(J2000) = +18d 42' 33.7"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 57%.

The mask-weighted light curve shows an initial sharp double-peak at T0
of duration ~0.5 seconds, transitioning to a FRED-like decay lasting ~5
seconds, after which the light curve returns to baseline.
T90 (15-350 keV) is 5.43 +- 2.22 sec (estimated error including systematics).

The time-averaged spectrum from T-0.07 to T+6.03 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.35 +- 0.31.  The fluence in the 15-150 keV band is 2.2 +- 0.4 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T-0.09 sec in the 15-150 keV band
is 1.3 +- 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/555600/BA/