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GCN Circular 15322

GRB 130925A: Possible signatures of binary nature in the afterglow - Request for observations
2013-10-10T14:57:27Z (11 years ago)
Remo Rufinni at ICRA <>
R. Ruffini, C.L. Bianco, M. Enderli, M. Muccino, A.V. Penacchioni, G.B.
Pisani, J.A. Rueda, N. Sahakyan, Y. Wang, L.Izzo report:

The observed X-ray emission in the afterglow of GRB 130925A (Lien et al., GCN 15247; Fitzpatrick et al., GCN 15255) presents an unprecedented sequence of flares departing from the canonical single power law decay (L \propto t^{-1.5}) observed in energetic GRBs-SNe (the "golden sample", Pisani et al. 2013, A&A 552, L5, arXiv:1304.1764). Correspondingly the X-ray Luminosity after 2*10^4 s in the rest-frame of the burst is almost constant (L \propto t^{-0.3}) and the energy emitted is a factor 30 larger than in the golden sample.

In the Induced Gravitational Collapse (IGC) paradigm, after the "input" due to a supernova explosion and the Black Hole formation (Ruffini 2013, IJMPD, 22, 1360009, arXiv:1310.1836), the "output" of a newly born Neutron Star from the Supernova and the Black Hole may remain bound in an elliptical orbit. This can explain the repeated flaring activity and the source of the larger observed energy.

In the canonical IGC scenario at z = 0.35 (Sudilovsky et al., GCN 15250, Vreeswijk et al., GCN 15249), assuming a 1998bw-like SN, a supernova should be expected to peak around the 10 - 16 October. It is crucial to perform optical observations in order to find out if the presence of the above mentioned binary nature in the "output" can modify the canonical scenario. Periodicities on time scales down to few minutes should be explored.
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