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Context. At large angular scales, the Pierre Auger Observatory has reported a significant dipole modulation in right ascension, while at intermediate angular scales, localized flux excesses have been identified by both the Auger and…

High Energy Astrophysical Phenomena · Physics 2026-01-13 D. Allard , J. Aublin , B. Baret , E. Parizot

The observation of cosmic ray particles with unexpected high energies is pushing astroparticle physics into a period of rapid progress both theoretically and experimentally. Different proposed models for the generation of these particles…

Astrophysics · Physics 2007-05-23 Maria Teresa Dova

Deviations from isotropy have been a key tool to identify the sources and the primary type of cosmic rays (CRs) at low energies. We argue that anisotropies due to blind regions induced by the Galactic magnetic field, the cosmological…

Astrophysics · Physics 2008-11-26 M. Kachelriess

Angular anisotropy techniques for cosmic diffuse radiation maps are powerful probes, even for quite small data sets. A popular observable is the angular power spectrum; we present a detailed study applicable to any unbinned source skymap…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Sheldon S. Campbell

The High Resolution Fly's Eye HiRes-I detector has now been in operation in monocular mode for over six years. During that time span, HiRes-I has accumulated a larger exposure to Ultra-High Energy Cosmic Rays (UHECRs) above 10^19 eV than…

Astrophysics · Physics 2019-08-15 Benjamin T. Stokes

The Cosmological Principle posits that the Universe is isotropic on the largest scales. While widely supported, this foundational assumption remains testable. We analyse the angular distribution of over one million quasars from the…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-04 Amit Mondal , Biswajit Pandey , Krishna Ghosh

A fundamental assumption in cosmology is that of statistical isotropy - that the universe, on average, looks the same in every direction in the sky. Statistical isotropy has recently been tested stringently using Cosmic Microwave Background…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-14 Caroline Zunckel , Dragan Huterer , Glenn D. Starkman

The two-point angular correlation function is a traditional method used to search for deviations from expectations of isotropy. In this paper we develop and explore a statistically descriptive three-point method with the intended…

Instrumentation and Methods for Astrophysics · Physics 2009-10-02 J. D. Hague , B. R. Becker , M. S. Gold , J. A. J. Matthews

Recent data from the Pierre Auger Observatory has revealed the presence of a large-scale dipole in the arrival direction distribution of ultra-high energy cosmic rays (UHECR). In this work, we build up an understanding of the diffusive…

High Energy Astrophysical Phenomena · Physics 2021-03-09 Rodrigo Guedes Lang , Andrew M. Taylor , Vitor de Souza

I discuss a theory of non-solar cosmic rays (CRs) based on a single type of CR source at all energies. All observed properties of CRs are predicted in terms of very simple and completely `standard' physics. The source of CRs is extremely…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. De Rujula

We test for an anisotropy in the mass of arriving cosmic-ray primaries associated with the galactic plane. The sensitivity to primary mass is obtained through the depth of shower maximum, $X_{\rm max}$, extracted from hybrid events measured…

High Energy Astrophysical Phenomena · Physics 2023-05-24 Eric Mayotte , Thomas Fitoussi

From deflections in galactic and extragalactic magnetic fields energy dependent structures in the arrival directions of ultra-high energy cosmic rays (UHECR) are expected. We propose to characterize these structures by the strength of…

Instrumentation and Methods for Astrophysics · Physics 2013-08-01 Martin Erdmann , Tobias Winchen

Fundamental information about the Universe is encoded in anisotropies of the Cosmic Microwave Background (CMB) radiation. To make full use of this information, an experiment must image the entire sky with the angular resolution,…

We analyse the distribution of position angles of 1 million galaxies from the Hyperleda catalogue, a sample that presents the galaxies coordinates in the celestial sphere, information that allows us to look for a possible privileged…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-08 R. S. Menezes , C. Pigozzo , S. Carneiro

Despite deflections by Galactic and extragalactic magnetic fields, the distribution of ultra-high energy cosmic rays (UHECRs) over the celestial sphere remains a most promising observable for the identification of their sources. Thanks to a…

It is suggested that essentially all of the UHECRs we detect, including those at the highest energy, originate in our Galaxy. It is shown that even if the density of sources decreases with Galactic radius, then the anisotropy and…

High Energy Astrophysical Phenomena · Physics 2016-04-27 David Eichler , Noemie Globus , Rahul Kumar , Eyal Gavish

It has recently been shown that the highest energy cosmic rays (CRs) may originate in the same cosmological objects producing $\gamma$-ray bursts. This model requires the presence of intergalactic magnetic fields (IGMF) to delay the arrival…

Astrophysics · Physics 2009-10-28 Eli Waxman , Jordi Miralda-Escude

We introduce new symmetry-based methods to test for isotropy in cosmic microwave background radiation. Each angular multipole is factored into unique products of power eigenvectors, related multipoles and singular values that provide 2 new…

Astrophysics · Physics 2008-11-26 Pramoda Kumar Samal , Rajib Saha , Pankaj Jain , John P. Ralston

Entering a new era of high-energy gamma-ray experiments, there is an exciting quest for the first detection of gamma-ray emission from clusters of galaxies. To complement these observational efforts, we use high-resolution simulations of a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Anders Pinzke , Christoph Pfrommer

Multichannel Cosmic Ray (CR) spectra and the large scale CR anisotropy can hardly be made compatible in the framework of conventional isotropic and homogeneous propagation models. These models also have problems explaining the longitude…

High Energy Astrophysical Phenomena · Physics 2012-06-13 Carmelo Evoli , Daniele Gaggero , Dario Grasso , Luca Maccione