A cumulative search for hard X/gamma-ray emission associated with fast radio bursts in Fermi/GBM data

R. Martone, C. Guidorzi, R. Margutti, L. Nicastro, L. Amati, F. Frontera, M. Marongiu, M. Orlandini, E. Virgilli
2019 Astronomy and Astrophysics  
Context. Fast Radio Bursts (FRBs) are millisecond-long bursts uniquely detected at radio frequencies. FRB 131104 is the only case for which a γ-ray transient positionally and temporally consistent was claimed. This high-energy transient had a duration of ∼400 s and a 15-150 keV fluence S_γ∼4×10^-6 erg cm^-2. However, the association with the FRB is still debated. Aims. We aim at testing the systematic presence of an associated transient high-energy counterpart throughout a sample of the FRB
more » ... lation. Methods. We used an approach like that used in machine learning methodologies to accurately model the highly-variable Fermi/GBM instrumental background on a time interval comparable to the duration of the proposed γ-ray counterpart of FRB 131104. A possible γ-ray signal is then constrained considering sample average lightcurves. Results. We constrain the fluence of the possible γ-ray signal in the 8-1000 keV band down to 6.4 × 10^-7 (7.1 × 10^-8) erg cm^-2 for a 200-s (1-s) integration time. Furthermore, we found the radio-to-gamma fluence ratio to be η>10^8 Jy ms erg^-1 cm^2. Conclusions. Our fluence limits exclude ∼ 94% of Fermi/GBM detected long gamma-ray bursts and ∼ 96% of Fermi/GBM detected short gamma-ray bursts. In addition, our limits on the radio-to-gamma fluence ratio point to a different emission mechanism from that of magnetar giant flares. Finally, we exclude a γ-ray counterpart as fluent as the one possibly associated with FRB 131104 to be a common feature of FRBs.
doi:10.1051/0004-6361/201936284 fatcat:ozxwryyurvdudbi5tpd55hwls4