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We explore the possibility that the diffuse gamma-ray background radiation (GBR) at high galactic latitudes could be dominated by inverse Compton scattering of cosmic ray (CR) electrons on the cosmic microwave background radiation and on…

Astrophysics · Physics 2009-10-31 Arnon Dar , A. De Rújula

We present a detailed model capable of explaining quantitatively the temperature fluctuations observed in luminous, large HII regions. The model is based on two assumptions which we justify on the basis of observations: that the major…

Astrophysics · Physics 2009-11-11 C. Giammanco , J. E. Beckman

We briefly review sources of cosmic rays, their composition and spectra as well as their propagation in the galactic and extragalactic magnetic fields, both regular and fluctuating. A special attention is paid to the recent results of the…

High Energy Astrophysical Phenomena · Physics 2012-05-09 Felix Aharonian , Andrei Bykov , Etienne Parizot , Vladimir Ptuskin , Alan Watson

During cosmic recombination, charged particles bind into neutral atoms and the mean free path of photons rapidly increases, resulting in the familiar diffusion damping of primordial radiation temperature variations. An additional effect is…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-04 Nathaniel Starkman , Glenn Starkman , Arthur Kosowsky

The accretion of a cloud of hydrogen at the surface of a small, heavy star produces a high energy mostly dissipated by electromagnetic radiation. The combination of the absorption and the redshift of this radiation by hydrogen explains all…

Astrophysics · Physics 2007-05-23 Jacques Moret-Bailly

We summarize the theoretical and observational status of the study of the Cosmic Microwave Background radiation. Its thermodynamic spectrum is a robust prediction of the Hot Big Bang cosmology and has been confirmed observationally. There…

Astrophysics · Physics 2009-10-31 Eric Gawiser , Joseph Silk

The ionization fraction of cosmic hydrogen, left over from the big bang, provides crucial fossil evidence for when the first stars and quasar black holes formed in the infant universe. Spectra of the two most distant quasars known show…

Astrophysics · Physics 2015-06-24 Stuart Wyithe , Abraham Loeb

Lyman-alpha photons from the first radiating sources in the Universe play a pivotal role in 21-cm radio detections of Cosmic Dawn and the Epoch of Reionization. Comments are provided on the effect of the hyperfine structure of hydrogen on…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-01 A. Meiksin

The interaction of exoplanets with their host stars causes a vast diversity in bulk and atmospheric compositions, and physical and chemical conditions. Stellar radiation, especially at the shorter wavelengths, drives the chemistry in the…

Earth and Planetary Astrophysics · Physics 2021-12-08 Daniele Locci , Antonino Petralia , Giuseppina Micela , Antonio Maggio , Angela Ciaravella , Cesare Cecchi-Pestellini

Water ice is abundant both astrophysically, for example in molecular clouds, and in planetary systems. The Kuiper belt objects, many satellites of the outer solar system, the nuclei of comets and some planetary rings are all known to be…

Astrophysics · Physics 2009-11-13 Weijun Zheng , David Jewitt , Ralf I. Kaiser

Cosmic structures at large scales represent the earliest and most extended form of matter condensation. In this lecture we review the application of the methods and concepts of modern statistical physics to these structures. This leads to a…

Astrophysics · Physics 2017-08-23 Luciano Pietronero , Francesco Sylos Labini

The first, self-consistent calculations are presented of the cosmological, H2-dissociating UV background produced during the epoch of reionization by the sources of reionization. Large-scale radiative transfer simulations of reionization…

Astrophysics · Physics 2015-05-13 Kyungjin Ahn , Paul R. Shapiro , Ilian T. Iliev , Garrelt Mellema , Ue-Li Pen

Hadronic cosmic particles (cosmic rays) and gamma rays are constantly absorbed in the Earth's atmosphere and result in air showers of secondary particles. Cherenkov radiation from these atmospheric events is used to measure cosmic gamma…

High Energy Astrophysical Phenomena · Physics 2025-09-05 Clara E. Leitgeb , Robert D. Parsons , Andrew M. Taylor , Kenneth J. Ragan , David Berge , Cigdem Issever

Investigation of the cosmic microwave background formation processes is one of the most actual problem at present time. In this paper we analyze the response of the hydrogen atom to the external photon fields. Field characteristics are…

Atomic Physics · Physics 2015-06-04 D. Solovyev , V. K. Dubrovich , G. Plunien

The rate of ionization by cosmic rays in interstellar gas directly associated with gamma-ray emitting supernova remnants is for the first time calculated to be several orders of magnitude larger than the Galactic average. Analysis of…

Astrophysics of Galaxies · Physics 2015-05-28 J. K. Becker , J. H. Black , M. Safarzadeh , F. Schuppan

Cosmic rays produce molecular cluster ions as they pass through the lower atmosphere. Neutral molecular clusters such as dimers and complexes are expected to make a small contribution to the radiative balance, but atmospheric absorption by…

Atmospheric and Oceanic Physics · Physics 2013-03-08 K. L. Aplin , M. Lockwood

We have developed a model which aims to reproduce observational data of many kinds related to cosmic-ray origin and propagation: direct measurements of nuclei, antiprotons, electrons and positrons, gamma-rays, and synchrotron radiation. Our…

Astrophysics · Physics 2007-05-23 A. W. Strong , I. V. Moskalenko

The spatial clustering of galaxies in galaxy clusters implies that the background of infrared (IR) light in the intracluster medium (ICM) may exceed the universal background. Cosmic rays injected within the ICM propagate diffusively and at…

Astrophysics · Physics 2009-11-13 Daniel De Marco , Pasquale Blasi , Patricia Hansen , Todor Stanev

The physical processes involved in diffusion of Galactic cosmic rays in the interstellar medium are addressed. We study the possibility that the nonlinear MHD cascade sets the power-law spectrum of turbulence which scatters charged…

Astrophysics · Physics 2008-11-26 V. S. Ptuskin , I. V. Moskalenko , F. C. Jones , A. W. Strong , V. N. Zirakashvili

Coherent backscattering is a coherence effect in the propagation of waves through disordered media involving two or more scattering events. Here, we report on the observation of coherent backscattering from individual atoms and their mirror…

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