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The contribution of the Unresolved Extragalactic Radio Sources to the diffuse brightness of the sky was evaluated using the source number - flux measurements available in literature. We first optimized the fitting function of the data based…

Astrophysics · Physics 2009-11-13 M. Gervasi , A. Tartari , M. Zannoni , G. Boella , G. Sironi

The low frequency tail of the CMB spectrum, down along the radio range (~1 GHz), may carry weak spectral distortions which are fingerprints of processes occurred during different epochs of the thermal history of the Universe, from z~3\times…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-25 Andrea Tartari , Mario Zannoni , Massimo Gervasi , Giorgio Sironi , Sebastiano Spinelli

We examine the brightness of the Cosmic Radio Background (CRB) by comparing the contribution from individual source counts to absolute measurements. We use a compilation of radio counts to estimate the contribution of detected sources to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Tessa Vernstrom , Douglas Scott , Jasper Wall

We estimate the contribution of extragalactic radio sources to fluctuations in sky temperature over the range of frequencies (10-300 GHz) used for Cosmic Microwave Background (CMB) anisotropy measurements. CMB anisotropy observations at…

Astrophysics · Physics 2007-05-23 Aaron Sokasian , Eric Gawiser , 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

It has recently become apparent that the background level of diffuse radio emission on the sky is significantly higher than the level that can result from known extragalactic radio source classes or our Galaxy given our current…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-02 J. Singal

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

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

Contribution of resolved and unresolved extragalactic point sources to the low-frequency sky spectrum is a potentially non-negligible part of the astrophysical foregrounds for cosmic dawn 21-cm experiments. The clustering of such point…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-01 Shikhar Mittal , Girish Kulkarni , Dominic Anstey , Eloy de Lera Acedo

We present the first targeted measurement of the power spectrum of anisotropies of the radio synchrotron background, at 140 MHz where it is the overwhelmingly dominant photon background. This measurement is important for understanding the…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-06 A. R. Offringa , J. Singal , S. Heston , S. Horiuchi , D. M. Lucero

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

The Galactic disc is opaque to radio waves from extragalactic sources with frequencies nu less than ~3 MHz. However, radio waves with kHz, Hz, and even lower frequencies may propagate through the intergalactic medium (IGM). I argue that the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Brian C. Lacki

Recent measurements of the temperature of the sky in the radio band, combined with literature data, have convincingly shown the existence of a cosmic radio background with an amplitude of $\sim 1$ K at 1 GHz and a spectral energy…

Cosmology and Nongalactic Astrophysics · Physics 2011-10-18 Pier Paolo Ponente , Yago Ascasibar , Jose Maria Diego

We present deep 1.4 GHz source counts from $\sim$5 deg$^2$ of the continuum Early Science data release of the MeerKAT International Gigahertz Tiered Extragalactic Exploration (MIGHTEE) survey down to $S_{1.4\textrm{GHz}}\sim$15 $\mu$Jy.…

We conduct a stacking analysis using 1.4 GHz NRAO VLA Sky Survey (NVSS) detections and Planck all-sky maps to estimate the differential source counts down to the few 100 $\mu$Jy level at 30, 44, 70 and 100 GHz. Consequently, we are able to…

Astrophysics of Galaxies · Physics 2018-07-11 Eric J. Murphy , Ranga-Ram Chary

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

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 recent detection of the "cosmic dawn" redshifted 21 cm signal at 78 MHz by the EDGES experiment differs significantly from theoretical predictions. In particular, the absorption trough is roughly a factor of two stronger than the most…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-16 Jayce Dowell , Greg B. Taylor

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

Building the radio sky template are crucial for detecting the 21 cm emission line signal from the Epoch of Reionization (EoR), as well as for other cosmological research endeavors. Utilizing data from the LOFAR Two-meter Sky Survey (LoTSS)…

Astrophysics of Galaxies · Physics 2024-11-07 Jinyang Lin , Zhenghao Zhu , Renyi Ma , Anna Bonaldi , Huanyuan Shan
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