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GCN Circular 39245

Subject

GRB 250207A: Swift-BAT refined analysis

Date

2025-02-09T00:53:00Z (2 days ago)

From

Rahul Gupta at NASA GSFC <rahul.gupta@nasa.gov>

Via

Web form

M. J. Moss (GSFC), S. D. Barthelmy (GSFC),
M. Ferro (INAF-OAB), R. Gupta (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (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 250207A (trigger #1287821)
(Ferro, et al., GCN Circ. 39182Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 16.097, -12.165 deg which is 
   RA(J2000)  =  01h 04m 23.4s 
   Dec(J2000) = -12d 09' 55.0" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 72%.
 
The masked weighted BAT light curve shows a prominent multi-peaked structure, with the most significant activity occurring within the first 50 seconds after the trigger. T90 (15-350 keV) is 52.54 +- 19.87 sec (estimated error including systematics).
 
The time-averaged spectrum from T-6.60 to T+100.22 sec is the best fit by a simple power-law model.  The power law index of the time-averaged spectrum is 1.27 +- 0.08.  The fluence in the 15-150 keV band is 3.7 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+7.01 sec in the 15-150 keV band is 2.6 +- 0.2 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/1287821