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arXiv · 1606.00314

On the GBM event seen 0.4 sec after GW 150914

J. Greiner·J. M. Burgess·V. Savchenko·H. -F. Yu
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Abstract

In view of the recent report by Connaughton we analyse continuous TTE data of Fermi-GBM around the time of the gravitational wave event GW 150914. We find that after proper accounting for low count statistics, the GBM transient event at 0.4 s after GW 150914 is likely not due to an astrophysical source, but consistent with a background fluctuation, removing the tension between the INTEGRAL/ACS non-detection and GBM. Additionally, reanalysis of other short GRBs shows that without proper statistical modeling the fluence of faint events is over-predicted, as verified for some joint GBM-ACS detections of short GRBs. We detail the statistical procedure to correct these biases. As a result, faint short GRBs, verified by ACS detections, with significances in the broad-band light curve even smaller than that of the GBM-GW150914 event are recovered as proper non-zero source, while the GBM-GW150914 event is consistent with zero fluence.

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J. Greiner, J. M. Burgess, V. Savchenko, H. -F. Yu. 2016-06-01. On the GBM event seen 0.4 sec after GW 150914. https://doi.org/10.3847/2041-8205/827/2/l38

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