Fermi-LAT observations of GRBs with weak LAT emission
  We present the analysis results of three Gamma-Ray Bursts (GRBs) detected by
the Gamma-ray Burst Monitor (GBM) and the Large Area Telescope (LAT) onboard
Fermi: the two long GRB 080825C and GRB 090217, and the first short burst with
GeV photons GRB 081024B. The emission from GRB 081024B observed by the LAT
above 100 MeV is delayed with respect to the GBM trigger, and significantly
extends after the low-energy episode. Some hints for spectral hardening was
observed in this burst as well as in GRB 080825C, possibly related to a
separate and harder component showing up at late times. Conversely, GRB 090217
does not exhibit any noticeable feature. Together with the other bright LAT
detected bursts (e.g. GRB 080916C and GRB 090510), these observations help to
classify the GRB properties and give new insight on the acceleration mechanisms
responsible for their emission at the highest energies.
