  The extragalactic background light (EBL) is all the electromagnetic energy
released by resolved and unresolved extragalactic sources since the
recombination era. Its intensity and spectral shape provide information about
the evolution of galaxies throughout cosmic history. Since direct observations
of the EBL are very difficult to perform, the study of the interaction between
the low energy EBL photons and high energy photons from distant extragalactic
sources becomes relevant to constrain the EBL intensity. The main goal of this
study is to investigate the opacity of the EBL to gamma rays by observing a
sample of active galaxies nuclei (AGN) with the High Altitude Water Cherenkov
(HAWC) Gamma-Ray Observatory. Current gamma-ray observations up to 20 TeV
performed by Imaging Atmospheric Cherenkov Telescopes (IACTs) have constrained
the EBL intensity in the 0.1-50 $\mu$m region. HAWC, which monitors the
gamma-ray sky in the 100 GeV to 100 TeV energy range, will be able to detect
about 10 AGN with the first year of HAWC data based on the extrapolation of
steady-state spectra from the GeV band to TeV, and thus constrain the EBL in
the poorly-measured 1-100 $\mu$m range.
