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Title: The isotropic radio background revisited

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.
Authors:
;  [1] ;  [2] ;  [3]
  1. Dipartimento di Fisica Teorica, Università di Torino, via P. Giuria 1, I–10125 Torino (Italy)
  2. Instituto de Física Corpuscular – CSIC/U. Valencia, Parc Científic, calle Catedrático José Beltrán, 2, E-46980 Paterna (Spain)
  3. Institut de Physique Théorique, CEA/Saclay, F-91191 Gif-sur-Yvette Cédex (France)
Publication Date:
OSTI Identifier:
22373670
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 04; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BRIGHTNESS; EMISSION; GHZ RANGE 01-100; MAPS; MHZ RANGE; ORIGIN; SKY; SYNCHROTRON RADIATION; SYNCHROTRONS