Abstract The multiband nonthermal emissions in radio, X-ray, and very high-energy (VHE) γ-ray bands from two distant blazars, H 2356-309 and 1ES 1218+304, have been detected, and, especially from recent observations with the Suzaku, MAGIC and VERITAS telescopes, clearly reveal nonthermal power-law spectra. We study the broadband nonthermal spectra of the two sources by using a combination of a onezone homogeneous synchrotron self-Compton (SSC) model and an inhomogeneous conical jet model, where the new external background light (EBL) model is taken into account. The results show that (1) the nonthermal emissions of the two blazars, ranging from X-rays to VHE γ-rays, are from the homogeneous zone whereas the emissions in the radio bands can be explained as the radiation from the inhomogeneous conical jet; (2) a strict lower-limit EBL model can be used to explain their observed spectra well.

Keywords radiation mechanisms — active-BL Lacertae objects — TeV blazars: individual (H 2356–309, 1ES 1218+304)

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