Extragalactic background light inferred from AEGIS galaxy SED-type
  fractions
  The extragalactic background light (EBL) is of fundamental importance both
for understanding the entire process of galaxy evolution and for gamma-ray
astronomy. However, the overall spectrum of the EBL between 0.1 and 1000
microns has never been determined directly neither from observed luminosity
functions (LFs), over a wide redshift range, nor from any multiwavelength
observation of galaxy spectral energy distributions (SEDs). The evolving,
overall spectrum of the EBL is derived here utilizing a novel method based on
observations only. The changing fractions of quiescent galaxies, star-forming
galaxies, starburst galaxies and active galactic nucleus (AGN) galaxies from
redshift 0.2 to 1 are estimated, and two alternative extrapolations of SED
types to higher redshifts are considered. This allows calculation of the
evolving EBL. The EBL uncertainties in our modelling based directly on the data
are quantified, and their consequences for attenuation of very-high-energy
gamma-rays due to pair production on the EBL are discussed. It is concluded
that the EBL seems well constrained from the UV to the mid-IR at an intensity
level roughly matching galaxy count data. Independent efforts from IR and
gamma-ray astronomy are needed in order to reduce the uncertainties in the
far-IR.
