New synthesis models of consistent extragalactic background light over
  cosmic time
  We present new synthesis models of the extragalactic background light (EBL)
from far infra-red (FIR) to TeV gamma-rays, with an emphasis on the extreme
ultraviolet (UV) background which is responsible for the observed ionization
and thermal state of the intergalactic medium across the cosmic time. Our
models use updated values of the star formation rate density and dust
attenuation in galaxies, QSO emissivity, and the distribution of H I gas in the
IGM. Two of the most uncertain parameters in these models, the escape fraction
of H I ionizing photons from galaxies and the spectral energy distribution
(SED) of QSOs, are determined to be consistent with the latest measurements of
H I and He II photoionization rates, the He II Lyman-alpha effective optical
depths, various constraints on H I and He II reionization history and many
measurements of the local EBL from soft X-rays till gamma-rays. We calculate
the EBL from FIR to TeV gamma-rays by using FIR emissivities from our previous
work and constructing an average SED of high-energy emitting QSOs, i.e, type-2
QSOs and blazars. For public use, we also provide the EBL models obtained using
different QSO SEDs at extreme-UV energies over a wide range of redshifts. These
can be used to quantify uncertainties in the parameters derived from
photoionization models and numerical simulations originating from the allowed
variations in the UV background radiation.
