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The low-frequency radio sky is dominated by the diffuse synchrotron emission of our Galaxy and extragalactic radio sources related to Active Galactic Nuclei and star-forming galaxies. This foreground emission is much brighter than the…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-30 Emma Chapman , Vibor Jelić

We investigate different scenarios for the origin of the extragalactic radio background. The surface brightness of the background, as reported by the ARCADE 2 collaboration, is several times higher than that which would result from…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 J. Singal , L. Stawarz , A. Lawrence , V. Petrosian

Synchrotron emission is an important process in Galactic dynamics and a potentially confusing foreground for cosmic microwave background (CMB) radiation observations. Though the mechanism of synchrotron emission is well understood, the…

Astrophysics · Physics 2007-05-23 George F. Smoot

Despite an intense theoretical and experimental effort over the past decade, observations of the extragalactic radio background at multiple frequencies below 10 GHz are not understood in terms of known radio sources, and may represent a…

High Energy Physics - Phenomenology · Physics 2023-08-02 Andrea Caputo , Hongwan Liu , Siddharth Mishra-Sharma , Maxim Pospelov , Joshua T. Ruderman

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…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Nicolao Fornengo , Roberto A. Lineros , Marco Regis , Marco Taoso

Analyses of measurements of the distribution of absolute brightness temperature over the radio sky have led recently to suggestions that there exists a substantial unexplained extragalactic radio background. Consequently, there have been…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Ravi Subrahmanyan , Ramanath Cowsik

Galactic synchrotron emission is a potentially confusing foreground, both in total power and in polarization, to the Cosmic Microwave Background Radiation. It also contains much physical information in its own right. This review examines…

Astrophysics · Physics 2007-05-23 R. D. Davies , A. Wilkinson

The origin of the radio synchrotron background (RSB) is currently unknown. Its understanding might have profound implications in fundamental physics or might reveal a new class of radio emitters. In this work, we consider the scenario in…

Cosmic ray protons generate gamma-rays, neutrinos, and secondary electrons and positrons (e+/-) through pion-producing collisions with gas atoms. Any synchrotron or Inverse Compton (IC) radiation from secondary e+/- is therefore accompanied…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Brian C. Lacki

The ARCADE 2 collaboration has reported a significant excess in the isotropic radio background, whose homogeneity cannot be reconciled with clustered sources. This suggests a cosmological origin prior to structure formation. We investigate…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-06 James M. Cline , Aaron C. Vincent

The gamma-ray background is still a subject under great debate. All phenomena in the universe emitting gamma-rays can contribute directly as diffuse emission or as an isotropic component from unresolved point sources. The question of the…

Astrophysics · Physics 2007-11-29 Tanja M. Kneiske

The universe is filled with a diffuse and isotropic extragalactic background of gamma-ray radiation, containing roughly equal energy flux per decade in photon energy between 3 MeV-100 GeV. The origin of this background is one of the…

Astrophysics · Physics 2011-05-05 Abraham Loeb , Eli Waxman

We make a new estimate of the extragalactic radio background down to kHz frequencies based on the observed luminosity functions and radio spectra of normal galaxies and radio galaxies. We have constructed models for the spectra of these two…

Astrophysics · Physics 2010-11-30 R. J. Protheroe , P. L. Biermann

We present a short overview on the extragalactic background radiation from radio to X-rays, with an eye to the relation to galaxy formation and emphasizing on astrophysical backgrounds (as opposed to cosmological). As the radio background,…

Astrophysics · Physics 2007-05-23 G. De Zotti , A. Franceschini , L. Toffolatti , P. Mazzei , L. Danese

New calculations of the Galactic contamination over microwave background radiation anisotropies are carried out. On one hand, when a frequency-dependent contrast of molecular clouds with respect to the Galactic background of the diffuse…

Astrophysics · Physics 2011-05-23 M. Lopez-Corredoira

We summarize the radio synchrotron background workshop that took place July 19-21, 2017 at the University of Richmond. This first scientific meeting dedicated to the topic was convened because current measurements of the diffuse radio…

The LWA will be well suited to address many important questions about the physics and astrophysics of extragalactic synchrotron sources. Good low-frequency data will enable major steps forward in our understanding of radio galaxy physics,…

Astrophysics · Physics 2007-05-23 J. A. Eilek , F. N. Owen , T. Markovic

The origin of the extragalactic gamma-ray background is a pressing cosmological mystery. The Fermi Gamma-Ray Space Telescope has recently measured the intensity and spectrum of this background; both are substantially different from previous…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-16 Brian D. Fields , Vasiliki Pavlidou , Tijana Prodanovic

The indirect detection of cosmic rays via the radio signal of extensive air showers is gaining a lot of ground. Many new arrays of radio antennas are under construction or in the phase of development. Calibrating these arrays is important…

Instrumentation and Methods for Astrophysics · Physics 2023-01-30 Max Büsken , Tomáš Fodran , Tim Huege

Here is reviewed our current understanding of Galactic and extragalactic diffuse gamma-ray emission. The spectrum of the extragalactic gamma-ray background above 30 MeV can be well described by a power law with photon index s=2.1. In the…

Astrophysics · Physics 2007-05-23 Martin Pohl
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