TITLE: GCN CIRCULAR NUMBER: 38108 SUBJECT: GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission DATE: 24/11/07 00:52:08 GMT FROM: Jimmy DeLaunay at Penn State delauj2@gmail.com

James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:

Swift/BAT GUANO detected and localized GRB 241105A (GCN 38091). GRB 241105A was also detected by Fermi/GBM (GCN 38104), GOTO (GCN 38088), Swift-XRT (GCN 38098), SVOM/VT (GCN 38099), VLT/FORS2 (GCN 38097), and Konus-Wind (GCN 38103).

The burst was detected at a partial coding fraction of 14%.

The mask-weighted light curve shows a short, strong pulse with a duration of ~2 s followed by a longer extended emission with a duration of ~75 s. Consistent with what was observed by both Fermi/GBM (GCN 38104) and Konus-Wind (GCN 38103). T90 (15 - 350 keV) is 72.8 s +/- 9.7 s .

The time-average spectrum over T100 from T0 - 0.5 s to T0 + 77.8 s is best fit by a simple power-law with an index of 1.33 +/- 0.20. The 15 - 150 keV fluence is 2.5 +/- 0.3 x 10^-6 erg/cm2.

Both the initial spike and the extended emission are best fit by simple power-laws with consistent spectral indices. ~77% of the fluence is contained in the extended emission.

The initial spike (T0 - 1.1 s to T0 + 1.3 s) has a best fit spectral index of 1.65 +/- 0.20 with a 15 - 150 keV fluence of 5.6 +/- 0.7 x 10^-7 erg/cm2.

The extended emission (T0 + 1.3 s to T0 + 77.8 s) has a best fit spectral index of 1.26 +/- 0.25 with a 15 - 150 keV fluence of 1.9 +/- 0.3 x 10^-6 erg/cm2.

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