  During the process of structure formation in the universe matter is converted
into radiation through a variety of processes such as light from stars,
infrared radiation from cosmic dust and gravitational waves from binary black
holes/neutron stars and supernova explosions. The production of this
astrophysical radiation background (ARB) could affect the expansion rate of the
universe and the growth of perturbations. Here, we aim at understanding to
which level one can constraint the ARB using future cosmological observations.
We model the energy transfer from matter to radiation through an effective
interaction between matter and astrophysical radiation. Using future supernova
data from LSST and growth-rate data from Euclid we find that the ARB density
parameter is constrained, at the 95% confidence level, to be
$\Omega_{ar_0}<0.008$. Estimates of the energy density produced by well-known
astrophysical processes give roughly $\Omega_{ar_0}\sim 10^{-5}$. Therefore, we
conclude that cosmological observations will only be able to constrain exotic
or not-well understood sources of radiation.
