Do All Long-duration Gamma-Ray Bursts Emit GeV Photons?

GRB 190114C extends the focus of gamma-ray burst (GRB) research to the high-energy regime, in which a prime question is "Do all long-duration GRBs emit GeV photons?" Based on the Fermi Large Area Telescope (LAT) 10 yr observations, 54 GRBs initially within the Fermi-LAT field of view and with known redshift are sampled. Within 26 of these GRBs at least one GeV photon has been detected with a probability of >95%, while the other 28 GRBs have no confident GeV photon detection. We hypothesize that all the samples intrinsically emit GeV photons, and the lack of detection is due to the limited capacity of the satellite. We estimate the theoretical number of photons that LAT receives by considering the GRB energy, the distance, and the LAT effective area. Results show, within the uncertainty, that all 26 GRBs with GeV photon detection have a theoretical photon number of >1, and 27 out of 28 GRBs without GeV photon detection have a theoretical photon number of <1. This agreement tends to support our hypothesis and give an answer of "yes" to our initial question.