ON THE FERMI -GBM EVENT 0.4 s AFTER GW150914
- Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, D-85748 Garching (Germany)
- Oskar Klein Centre for Cosmoparticle Physics, SE-106 91 Stockholm (Sweden)
In view of the recent report by Connaughton et al., we analyze continuous time-tagged event (TTE) data of Fermi -gamma-ray burst monitor (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 broadband 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.
- OSTI ID:
- 22654195
- Journal Information:
- Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 827; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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