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Related papers: Diffuse Background Radiation

200 papers

We report measurements of anisotropy in the cosmic microwave background radiation over the multipole range l ~ 200 - 3500 with the Cosmic Background Imager based on deep observations of three fields. These results confirm the drop in power…

In this work, we revisit the all-sky Galactic diffuse $\gamma$-ray emission taking into account the new measurements of cosmic ray electron/positron spectrum by PAMELA, ATIC and Fermi, which show excesses of cosmic electrons/positrons…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Juan Zhang , Qiang Yuan , Xiao-Jun Bi

Gamma rays from TeV blazars have been detected by ground-based experiments for more than two decades. We have collected the most extensive set of archival spectra from these sources in order to constrain the processes affecting gamma-ray…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-26 Jonathan Biteau , David A. Williams

We have studied small scale (2 arcmin) spatial variation of the diffuse UV radiation using a set of 11 GALEX deep observations in the constellation of Draco. We find a good correlation between the observed UV background and the IR 100…

Astrophysics of Galaxies · Physics 2015-05-20 N. V. Sujatha , Jayant Murthy , Rahul Suresh , Richard Conn Henry , Luciana Bianchi

The redshifted 1420 MHz emission from the HI in unresolved damped Lyman-\alpha clouds at high z will appear as a background radiation in low frequency radio observations. This holds the possibility of a new tool for studying the universe at…

Astrophysics · Physics 2009-10-31 Somnath Bharadwaj , Biman B. Nath , Shiv K. Sethi

We calibrate here cosmological radiative transfer simulation with ATON/RAMSES with a range of measurements of the Lyman alpha opacity from QSO absorption spectra. We find the Lyman alpha opacity to be very sensitive to the exact timing of…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-23 Jonathan Chardin , Martin G. Haehnelt , Dominique Aubert , Ewald Puchwein

The diffuse high-latitude H-alpha background is widely believed to be predominantly the result of in-situ recombination of ionized hydrogen in the warm interstellar medium of the Galaxy. Instead, we show that both a substantial fraction of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 A. N. Witt , B. Gold , F. S. Barnes , C. T. DeRoo , U. P. Vijh , G. J. Madsen

We discuss the structure, physical nature, dynamic genesis of clearly detected diffuse backgrounds (radiations) in the Universe. From the point of view of Wave Universe concept it is shown, that observed Backgrounds Hierarchy (Polyphony of…

General Physics · Physics 2007-05-23 A. M. Chechelnitsky

Terzan 5, a globular cluster (GC) prominent in mass and population of compact objects, is searched for diffuse X-ray emission, as proposed by several models. We analyzed the data of an archival Chandra observation of Terzan 5 to search for…

High Energy Astrophysical Phenomena · Physics 2015-05-18 P. Eger , W. Domainko , A. -C. Clapson

Dark photons are a well-motivated candidate for dark matter, but their detection becomes challenging for ultralight masses with both experimental and astrophysical probes. In this work, we propose a new approach to explore this regime…

High Energy Physics - Phenomenology · Physics 2025-01-06 Javier F. Acevedo , Amit Bhoonah , Kun Cheng

Diffuse Galactic gamma-ray emission is produced in interactions of cosmic rays with gas and ambient photon fields and thus provides us with an indirect measurement of cosmic rays in various locations in the Galaxy. The diffuse gamma-ray…

Astrophysics · Physics 2007-05-23 Martin Pohl

We investigate the possible parametric growth of photon amplitudes in a background of axion-like particle (ALP) dark matter. The observed extragalactic background radiation limits the allowed enhancement effect. We derive the resulting…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-11 Günter Sigl , Pranjal Trivedi

During the epoch of reionization the 21cm signal is sensitive to the scattering rate of the ultraviolet photons, redshifting across the Lyman_alpha resonance. Here we calculate the photon scattering rate profile for a single ultraviolet…

Astrophysics · Physics 2009-11-13 Leonid Chuzhoy , Zheng Zheng

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

The ultraviolet and optical background forms a baseline for any observation of the sky. It includes emission lines and scattered light from the atmosphere; resonant scattering from the Lyman lines of interplanetary hydrogen and the…

Astrophysics of Galaxies · Physics 2019-09-26 Jayant Murthy , M. S. Akshaya , S. Ravichandran

It is predicted that the spectrum of radio emission from the whole sky should show a dip arising from the action of the light from the first stars on the hydrogen atoms in the surrounding gas, which causes the 21-cm line to appear in…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-27 Richard Hills , Girish Kulkarni , P. Daniel Meerburg , Ewald Puchwein

We present a map of the diffuse ultraviolet cosmic background in two wavelength bands (FUV: 1530 {\AA}; NUV: 2310 {\AA}) over almost 75% of the sky using archival data from the GALEX mission. Most of the diffuse flux is due to…

Astrophysics of Galaxies · Physics 2010-11-30 Jayant Murthy , Richard C. Henry , N. V. Sujatha

Recent EGRET observations of the diffuse Galactic gamma-ray emission reveal a spectrum which is incompatible with the assumption that the cosmic ray spectra measured locally hold throughout the Galaxy: the spectrum above 1 GeV, where the…

Astrophysics · Physics 2009-11-07 I. Büsching , M. Pohl , R. Schlickeiser

Deep, 17.8 hours, narrow band imaging obtained at the ESO 3.5m New Technology Telescope has revealed extended (galaxy sized) Ly-alpha emission from a high redshift Lyman limit absorber. The absorber is a z(abs) approx. z(em) Lyman limit…

Astrophysics · Physics 2011-05-23 J. U. Fynbo , B. Thomsen , P. Moller

We present the results of the flux density measurements at 4.85 GHz and 10.45 GHz of a sample of 5998 NVSS radio sources with the Effelsberg 100 m telescope. The initial motivation was the need to identify the NVSS radio sources that could…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 E. Angelakis , A. Kraus , A. C. S. Readhead , J. A. Zensus , R. Bustos , T. P. Krichbaum , A. Witzel , T. J. Pearson