Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 35241

GRB 231129A: Swift-BAT refined analysis
2023-11-30T22:41:45Z (6 months ago)
Sibasish Laha at GSFC <>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
M. Moss (GSFC), T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU),M. Stamatikos (OSU)
(i.e. the Swift-BAT team):

Using the data set from T-61 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231129A (trigger #1199764)
(Gropp et al., GCN Circ. 35208).  The BAT ground-calculated position is
RA, Dec = 317.541, 41.530 deg which is
   RA(J2000)  =  21h 10m 09.8s
   Dec(J2000) = +41d 31' 48.3"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 46%.

The BAT  light curve shows a complex structure with a duration of ~ 130 sec.
T90 (15-350 keV) is 105.46 +- 1.83 sec (estimated error including systematics).

The time-averaged spectrum from T-1.75 to T+118.97 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.35 +- 0.17,
and Epeak of 83.7 +- 14.6 keV (chi squared 51.44 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.3 +- 0.0 x 10^-05 erg/cm2
and the 1-sec peak flux measured from T+88.71 sec in the 15-150 keV band is
4.8 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.78 +- 0.04 (chi squared 70.95 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level.

The results of the batgrbproduct analysis are available at

Looking for U.S. government information and services? Visit