GCN Circular 43563

Subject

GRB 260127A: Swift-BAT refined analysis

Event

GRB 260127A

Date

2026-01-29T21:16:56Z (2 days ago)

From

D. R. Sadaula at NASA GSFC <dev.r.sadaula@nasa.gov>

Via

Web form

T. Parsotan (GSFC), 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),
D. M. Palmer (LANL), T. Parsotan (GSFC),
D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU)
(i.e. the Swift-BAT team)
 
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 260127A (trigger #1444088)
(Kilingler et al., GCN Circ. 43529Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 231.879, 6.758 deg which is 
   RA(J2000)  =  15h 27m 30.9s 
   Dec(J2000) = +06d 45' 28.4" 
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 40%.
 
The classic pulse has a single peak that started around T+20 sec and has a structure before it at ~T+5 sec. The duration of the burst is ~100 sec.  T90 (15-350 keV) is 104.06 +- 19.41 sec (estimated error including systematics).
 
The time-averaged spectrum using multiple GTIs  from T-2.68 to T+7.62, T+9.00 to T+84.43 sec, and T+86.00 to T+117.04 sec is best fit by a simple power-law model.  The power law index of the time-averaged spectrum is 1.76 +- 0.15.  The fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+33.36 sec in the 15-150 keV band is 2.1 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence level. 
 
The results of the batgrbproduct analysis are available at
https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1444088