Study of gamma-ray and near-infrared emission of gamma-ray-loud blazars object

We have collected 29 gamma-ray-loud blazars (16 BL Lac objects and 13 flat-spectrum radio quasars) with both observed near-IR and gamma -ray flux densitees, with the following main results: (1)there is a very strong correlation between F-gamma and F-IR in the low state, and a weaker but also significant correlation between F-gamma and F-IR in the high state for 23 objects with both high and low state fluxes; (2) there is a very significant correlation between F-gamma and F-IR in the low state, and a weak correlation between F-gamma and F-IR in the high state for 29 sources; (3) there is a correlation between F-gamma and F-IR but not between F-gamma and F-O, and F-R for both the low and high state of 26 sources; (4) there is a strong correlation between F-gamma and F-IR in the low and high states for 15 BL Lac objects, but not for 11 flat-spectrum radio quasars. Possible constraints on the gamma -ray emission mechanism are discussed. We suggest that the main gamma-ray radiation mechanism is probably the synchrotron self-Compton process. The inverse Compton scattering of the radiation from hot circumnuclear dust with T-g = 2000K, which is located within the region of r approximate to 3pc, by beamed ultrarelativistic electrons is likely to be an important complementary mechanism. In addition, the gamma -ray emission may be somewhat different for BL Lac objects and flat-spectrum radio quasars.