Publication Date:
2013-09-22
Description:
[1] The observed γ -ray fluence distribution of Terrestrial Gamma-ray Flashes (TGFs) detected by the Fermi Gamma-ray Burst Monitor (GBM) is altered by instrumental effects. We perform corrections for deadtime, pulse pile-up and detection efficiency in a model independent manner. A sample of 106 GBM TGFs is selected to include both TGFs which triggered GBM and weaker TGFs found using an offline search. Detector deadtime and pulse pile-up lower the observed fluence of each TGF and the detection efficiency causes weaker TGFs to have a lower probability of detection than brighter TGFs. Monte Carlo simulations are performed in each case to correct for these effects. The corrected fluence distribution is well fit with a power-law of index α = –2.20 ± 0.13. This is consistent with previous estimates using other techniques. Neither a high-fluence cut-off nor a low-fluence limit is found. The fluence distribution is also expressed in units of TGF hour –1 km –2 versus photons cm –2 per TGF.
Print ISSN:
0148-0227
Topics:
Geosciences
,
Physics
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