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We present constraints on the density of halo dark matter candidates within the solar circle based on the anisotropy in the high energy gamma-ray background. The known galactic components of the gamma-ray background, in particular the…

Astrophysics · Physics 2007-05-23 R. Chary , E. L. Wright

We present a study of the spectral, polarimetric, morphological and environmental properties of the diffuse radio source 0809+39 using observations taken with the Westerbork Synthesis Radio Telescope, the Very Large Array, and archival…

Astrophysics · Physics 2009-11-13 Shea Brown , Lawrence Rudnick

Gigahertz-Peaked spectrum (GPS) sources are compact active galactic nuclei, presumably young precursors of bright radio sources. The study of GPS radio properties provides information about the features of synchrotron radiation in…

Astrophysics of Galaxies · Physics 2020-01-08 Yu. Sotnikova , T. Mufakharov , E. Majorova , M. Mingaliev , R. Udovitskiy , N. Bursov , T. Semenova

The near-infrared background between 0.5 $\mu$m to 2 $\mu$m contains a wealth of information related to radiative processes in the universe. Infrared background anisotropies encode the redshift-weighted total emission over cosmic history,…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-24 Chang Feng , Asantha Cooray , Jamie Bock , Tzu-Ching Chang , Olivier Doré , Mario G. Santos , Marta B. Silva , Michael Zemcov

We present a new model of the diffuse Galactic synchrotron radiation, concentrating on its angular anisotropies. While previous studies have focussed on either the variation of the emissivity on large (kpc) scales, or on fluctuations due to…

Astrophysics of Galaxies · Physics 2013-06-26 Philipp Mertsch , Subir Sarkar

Diffuse Galactic emission at low frequencies is a major contaminant for studies of redshifted $21$ cm line studies. Removal of these foregrounds is essential for exploiting the signal from neutral hydrogen at high redshifts. Analysis of…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-05 Sandeep Rana , Tuhin Ghosh , J. S. Bagla , Pravabati Chingangbam

Fluctuations in the Galactic synchrotron emission can be traced by the angular power spectrum of radio maps at low multipoles. At frequencies below few GHz, large-scale anisotropies are mainly induced by magnetic field turbulence. By…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Marco Regis

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

If the diffuse extragalactic gamma ray emission traces the large scale structures of the universe, peculiar anisotropy patterns are expected in the gamma ray sky. In particular, because of the cutoff distance introduced by the absorption of…

Astrophysics · Physics 2014-10-13 A. Cuoco , S. Hannestad , T. Haugbølle , G. Miele , P. D. Serpico , H. Tu

Current estimates of number counts of radio sources in the frequency range where the most sensitive Cosmic Microwave Background (CMB) experiments are carried out significantly under-represent sources with strongly inverted spectra. Hot…

Astrophysics · Physics 2009-10-31 Rosalba Perna , Tiziana Di Matteo

The scattering diameters of Sgr A* and several nearby OH masers (~ 1" at 1 GHz) indicate that a region of enhanced scattering is along the line of sight to the Galactic center. The scattering diameter of an extragalactic source seen through…

Astrophysics · Physics 2009-10-30 T. Joseph W. Lazio , James M. Cordes

A Gravitational Wave Background (GWB) is expected in the universe from the superposition of a large number of unresolved astrophysical sources and phenomena in the early universe. Each component of the background (e.g., from primordial…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-27 Abhishek Parida , Sanjit Mitra , Sanjay Jhingan

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

Galactic foreground emission is a limiting factor for precise cosmic microwave background (CMB) anisotropy measurements. We perform an angular power spectrum analysis (APS) of all-sky total intensity maps at 408 MHz and 1420 MHz, which are…

Astrophysics · Physics 2009-11-13 L. La Porta , C. Burigana , W. Reich , P. Reich

The shocks produced in the intergalactic medium during large-scale structure formation accelerate a population of highly relativistic electrons which emit synchrotron radiation due to intergalactic magnetic fields. In a previous paper (Loeb…

Astrophysics · Physics 2009-10-31 Eli Waxman , Abraham Loeb

We present an analysis of simultaneous multifrequency measurements of the Galactic emission in the 1-10 GHz range with 18 degrees, angular resolution taken from a high altitude site. Our data yield a determination of the synchrotron…

Astrophysics · Physics 2009-10-30 P. Platania , M. Bensadoun , M. Bersanelli , G. De Amici , A. Kogut , S. Levin , D. Maino , G. F. Smoot

The fine tuning of parameters required to reproduce our present day Universe suggests that our Universe may simply be a region within an eternally inflating super-region. Many other regions beyond our observable Universe would exist with…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-27 R. Chary

In recent years, the level of the extragalactic radio background has become a point of considerable interest, with some lines of argument pointing to an entirely new cosmological synchrotron background. The contribution of the known…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-18 M. J. Hardcastle , T. W. Shimwell , C. Tasse , P. N. Best , A. Drabent , M. J. Jarvis , I. Prandoni , H. J. A. Rottgering , J. Sabater , D. J. Schwarz

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

The origin of the Isotropic Diffuse $\gamma$-Ray Background (IGRB) is one of the most intriguing mystery in astrophysics. Recently the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has measured the IGRB spectrum…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Mattia Di Mauro
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