PT Journal
AU Fornengo, N
   Lineros, RA
   Regis, M
   Taoso, M
TI The isotropic radio background revisited
SO Journal of Cosmology and Astroparticle Physics
JI J. Cosmol. Astropart. Phys.
PY 2014
BP 008
EP 36pp
VL 04
IS 4
DI 10.1088/1475-7516/2014/04/008
LA English
DE cosmic ray theory; galactic magnetic fields; dark matter theory
AB We present an extensive analysis on the determination of the isotropic radio background. We consider six different radio maps, ranging from 22 MHz to 2.3 GHz and covering a large fraction of the sky. The large scale emission is modeled as a linear combination of an isotropic component plus the Galactic synchrotron radiation and thermal bremsstrahlung. Point-like and extended sources are either masked or accounted for by means of a template. We find a robust estimate of the isotropic radio background, with limited scatter among different Galactic models. The level of the isotropic background lies significantly above the contribution obtained by integrating the number counts of observed extragalactic sources. Since the isotropic component dominates at high latitudes, thus making the profile of the total emission flat, a Galactic origin for such excess appears unlikely. We conclude that, unless a systematic offset is present in the maps, and provided that our current understanding of the Galactic synchrotron emission is reasonable, extragalactic sources well below the current experimental threshold seem to account for the majority of the brightness of the extragalactic radio sky.
ER