Comparing gamma-ray flux and spectral variability of the BL Lac S5 0716+714 and FSRQ 3C 273

Since its launch in 2008, the Fermi-Large Area Telescope has opened a new era in high-energy astrophysics and revolutionized our knowledge of the gamma-ray sky. The physical properties of the bright gamma-ray blazars, how do they differ from those of gamma-ray weak blazars, and what are the characteristics of the two blazar sub-classes (FSRQs and BL Lacs), are some of the key questions which need to be explored to have a refined view of the AGN unification model. In this talk, I will present a comparison of the observed gamma-ray flux and spectral properties of the BL Lac object S5 0716+714 and the FSRQ 3C 273. The talk will be focused on a detailed analysis of the intra-day variability and associated spectral changes in the gamma-ray band to probe the location and size of the gamma-ray emission region.