相关论文: Is there an unaccounted excess Extragalactic Cosmi…
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…
If the radio background is coming from cosmological sources, there should be some amount of clustering due to the large scale structure in the universe. Simple models for the expected clustering combined with the recent measurement by…
Observations of the extragalactic radio background have uncovered a significant isotropic emission across multiple frequencies spanning from 22 MHz to 10 GHz. The intensity of this non-thermal emission component significantly exceeds the…
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,…
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…
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…
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…
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…
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…
Recent radio surveys have discovered a large number of low luminosity core dominated radio galaxies that are much more abundant than those at higher luminosities. These objects will be too faint in gamma-rays to be detected individually by…
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…
Recent measurements by the ARCADE2 experiment unambiguously show an excess in the isotropic radio background at frequencies below the GHz scale. We argue that this excess may be a natural consequence of the interaction of visible and dark…
The extragalactic background is composed of the emission from all astrophysical sources, both resolved and unresolved, in addition to any diffuse components. In the last decade, there has been significant progress in our understanding of…
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…
Observations by ARCADE-2 and other telescopes sensitive to low frequency radiation have revealed the presence of an isotropic radio background with a hard spectral index. The intensity of this observed background is found to exceed the flux…
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…
In 2018 the EDGES experiment claimed the first detection of the global cosmic 21cm signal, which featured an absorption trough centered around $z \sim 17$ with a depth of approximately -500mK. This amplitude is deeper than the standard…
Confusion noise due to extragalactic sources is a fundamental astrophysical limitation for experiments aimed at accurately determining the power spectrum of the Cosmic Microwave Background (CMB) down to arcmin angular scales and with a…
We study the origin of the extragalactic diffuse gamma-ray background using the data from the Fermi telescope. To estimate the background level, we count photons at high Galactic latitudes |b|>60 degrees. Subtracting photons associated to…
The extragalactic background radiation produced by distant galaxies emitting in the far infrared limits the sensitivity of telescopes operating in this range due to confusion. We have constructed a model of the infrared background based on…