Does the gamma-ray flux of the blazar 3C 454.3 vary on subhour time-scales?

In the early days of 2010 April, the blazar 3C 454.3 (z= 0.859) underwent a strong γ-ray outburst, reaching fluxes (E > 100 MeV) in excess of 10-5 photon cm-2 s-1. The Fermi Gamma-ray Space Telescope performed a 200 ks long pointed observation starting from 2010 April 5 19:38 utc. This allowed us to try probing the variability of the γ-ray emission on time-scales of hours or less. We found the variability on a few hours time-scale. On subhour time-scale we found no evidence of significant variability, although the present statistics is not yet conclusive and further observations are needed. © 2010 The Authors. Journal compilation © 2010 RAS.