We combine the recent estimate of the contribution of galaxies to the 3.6 \mu m intensity of the extragalactic background light ( EBL ) with optical and near-infrared ( IR ) galaxy counts to set new limits on intrinsic spectra of some of the most distant TeV blazars 1ES 0229+200 , 1ES 1218+30.4 , and 1ES 1101-232 , located at redshifts 0.1396 , 0.182 , and 0.186 , respectively .
The new lower limit on the 3.6 \mu m EBL intensity is significantly higher than the previous one set by the cumulative emission from resolved Spitzer galaxies .
Correcting for attenuation by the revised EBL , we show that the differential spectral index of the intrinsic spectrum of the three blazars is 1.28 \pm 0.20 or harder .
These results present blazar emission models with the challenge of producing extremely hard intrinsic spectra in the sub-TeV to multi-TeV regime .
These results also question the reliability of recently derived upper limits on the near-IR EBL intensity that are solely based on the assumption that intrinsic blazar spectra should not be harder than 1.50 ( Aharonian et al .
2006 ; Aharonian et al .
2007a ) .