GRB 240829A

S. Laha (GSFC/UMBC), K. L. Page (U Leicester), D. M. Palmer (LANL) and
A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 03:56:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240829A (trigger=1251252).  Swift did not slew to
the burst due to an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 143.059, -18.728 which is 
   RA(J2000) = 09h 32m 14s
   Dec(J2000) = -18d 43' 40"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex peak
structure with a duration of about 40 sec.  The peak count rate
was ~1500 counts/sec (15-350 keV), at ~1 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 12:04 UT on 2024 October 02. There will thus be no XRT
or UVOT data for this trigger before this time. 

Burst Advocate for this burst is S. Laha (sib.laha AT gmail.com). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
R. Gupta (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC), M. J. Moss (GSFC),
T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC),
T. Sakamoto (AGU) (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 240829A (trigger #1251252)
(Laha, et al., GCN Circ. 37333
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 ).  The BAT ground-calculated position is
RA, Dec = 143.079, -18.687 deg which is
   RA(J2000)  =  09h 32m 18.9s
   Dec(J2000) = -18d 41' 13.0"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 15%.
 
The mask-weighted light curve displays a combination of two to three dim fast-
rise-exponential-decay pulses. The T90 (15-350 keV) is 43.20 +- 10.47 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-12.53 to T+51.47 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.66 +- 0.11.  The fluence in the 15-150 keV band is 3.8 +- 0.3 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+10.97 sec in the 15-150 keV band
is 0.0 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

Swift did not slew to the BAT position due to the burst being sun constrained.

The results of the batgrbproduct analysis are available at
https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1251252