出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The study of the Extragalactic Background Light (EBL) is crucial to understand many astrophysical
problems (as the formation of first stars, the evolution of galaxies and the role of dust
emission). At present, one of the most powerful ways to put constraints on EBL is represented by
the study of the photon-photon absorption on gamma-ray spectra of TeV blazars. Adopting this
method, we found that, if the only contribution to the optical and Near Infrared (NIR) background
is given by galaxies, the spectrum of the blazar H 1426+428 cannot be fitted. To reproduce the observational
data of H 1426+428 a Near Infrared excess with respect to galaxy counts is required,
with amplitude consistent with both the Matsumoto et al. (2000) data with Kelsall’s model of
zodiacal light (ZL) subtraction and the DIRBE data with Wright’s model of ZL subtraction. The
derived constraints on the optical EBL are weaker, because the experimental errors on blazar data
are still bigger than the differences among various optical EBL models. In the mid-infrared the
SPITZER measurement of nIn=2.7 nW m2 sr1 at 24 μm, provides the best fit of the blazar
spectrum.
