TITLE: GCN CIRCULAR NUMBER: 36974 SUBJECT: GRB 240727A: Swift-BAT refined analysis DATE: 24/07/29 19:11:10 GMT FROM: Rahul Gupta at NASA GSFC rahul.gupta@nasa.gov

R. Gupta (GSFC), S. D. Barthelmy (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 240727A (trigger #1245074) (Parsotan, et al., GCN Circ. 36938). The BAT ground-calculated position is RA, Dec = 236.451, 8.612 deg which is RA(J2000) = 15h 45m 48.2s Dec(J2000) = +08d 36' 41.8" with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.

The mask-weighted BAT light curve shows a complex structure with a duration of ~ 215 sec. T90 (15-350 keV) is 177.88 +- 35.46 sec (estimated error including systematics).

The time-averaged spectrum from T-6.79 to T+201.06 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.62 +- 0.18. The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+3.12 sec in the 15-150 keV band is 0.4 +- 0.1 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/BATbursts/hand/1245074/bascript/top.html

View this GCN Circular online at https://gcn.nasa.gov/circulars/36974. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...