GCN Circular 13852
Subject
GRB 121011A, Swift-BAT refined analysis
Date
2012-10-11T21:14:11Z (12 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
J. L. Racusin (NASA/GSFC), T. Sakamoto (AGU), G. Sato (ISAS),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 121011A (trigger #535764)
(Racusin, et al., GCN Circ. 13845). The BAT ground-calculated position is
RA, Dec = 260.204, 41.123 deg, which is
RA(J2000) = 17h 20m 49.0s
Dec(J2000) = +41d 07' 22.4"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 32%.
The mask-weighted light curve shows a single pulse starting at ~T-9 sec,
peaking at ~T+1 sec, and ending at ~T+110 or ~T+150 sec.
T90 (15-350 keV) is 75.6 +- 12.7 sec (estimated error including systematics).
The time-averaged spectrum from T-7.45 to T+80.10 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 0.10 +- 0.73,
and Epeak of 101.5 +- 42.2 keV (chi squared 40.6 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 2.7 +- 0.7 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T-0.69 sec in the 15-150 keV band is
1.2 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.20 +- 0.14 (chi squared 49.2 for 57 d.o.f.). 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/535764/BA/