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Related papers: Cosmic Ray Anisotropy Analysis with a Full-Sky Obs…

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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

The IceCube Observatory provides our highest-statistics picture of the cosmic-ray arrival directions in the Southern Hemisphere, with over 700 billion cosmic-ray-induced muon events collected between May 2011 and May 2022. Using the larger…

Anisotropy in arrival directions of ultrahigh energy cosmic rays offers the most direct way to search for the sources of these particles. We present estimates of the angular correlation in the HiRes sample of stereo events above 10 EeV, and…

Astrophysics · Physics 2019-08-15 Chad Finley

After two years of operation, the High-Altitude Water Cherenkov (HAWC) Observatory has analyzed the TeV cosmic-ray sky over an energy range between $2.0$ and $72.8$ TeV. The HAWC detector is a ground-based air-shower array located at high…

High Energy Astrophysical Phenomena · Physics 2018-09-24 A. U. Abeysekara , R. Alfaro , C. Alvarez , J. D. Alvarez , R. Arceo , J. C. Arteaga-Velázquez , D. Avila Rojas , H. A. Ayala Solares , A. Becerril , E. Belmont-Moreno , S. Y. BenZvi , A. Bernal , J. Braun , K. S. Caballero-Mora , T. Capistrán , A. Carramiñana , S. Casanova , M. Castillo , U. Cotti , J. Cotzomi , C. De León , E. De la Fuente , R. Diaz Hernandez , S. Dichiara , B. L. Dingus , M. A. DuVernois , J. C. Díaz-Vélez , K. Engel , D. W. Fiorino , N. Fraija , J. A. García-González , F. Garfias , A. González Muñoz , M. M. González , J. A. Goodman , Z. Hampel-Arias , J. P. Harding , S. Hernandez , B. Hona , F. Hueyotl-Zahuantitla , C. M. Hui , P. Hüntemeyer , A. Iriarte , A. Jardin-Blicq , V. Joshi , S. Kaufmann , A. Lara , R. J. Lauer , W. H. Lee , H. León Vargas , A. L. Longinotti , G. Luis-Raya , R. Luna-García , D. López-Cámara , R. López-Coto , D. López-Cámara , R. López-Coto , K. Malone , S. S. Marinelli , O. Martinez , I. Martinez-Castellanos , J. Martínez-Castro , H. Martínez-Huerta , J. A. Matthews , P. Miranda-Romagnoli , E. Moreno , M. Mostafá , A. Nayerhoda , L. Nellen , M. Newbold , M. U. Nisa , R. Noriega-Papaqui , R. Pelayo , J. Pretz , E. G. Pérez-Pérez , Z. Ren , C. D. Rho , C. Rivière , D. Rosa-González , M. Rosenberg , E. Ruiz-Velasco , F. Salesa Greus , A. Sandoval , M. Schneider , H. Schoorlemmer , M. Seglar Arroyo , G. Sinnis , A. J. Smith , R. W. Springer , P. Surajbali , I. Taboada , O. Tibolla , K. Tollefson , I. Torres , G. Vianello , L. Villaseñor , T. Weisgarber , F. Werner , S. Westerhoff , J. Wood , T. Yapici , A. Zepeda , H. Zhou

The cosmological principle asserts that the Universe is homogeneous and isotropic on large enough scales. However, alternative cosmological models can bring about anisotropies through local inhomogeneities, anisotropic evolution, or exotic…

We use more than two years of data from the Pierre Auger Observatory to search for anisotropies on large scales in different energy windows. We account for various systematics in the acceptance, in particular due to the array growth and…

Astrophysics · Physics 2019-08-13 E. Armengaud

There is a growing set of observational data demonstrating that cosmic rays exhibit small-scale anisotropies (5-30 deg) with amplitude deviations lying between 0.01-0.1 percent that of the average cosmic ray flux. A broad range of models…

High Energy Astrophysical Phenomena · Physics 2021-01-20 Margot Fitz Axen , Julia Speicher , Aimee Hungerford , Chris L. Fryer

Conventional cosmic-ray propagation models usually assume an isotropic diffusion coefficient to account for the random deflection of cosmic rays by the turbulent interstellar magnetic field. Such a picture is very successful in explaining…

High Energy Astrophysical Phenomena · Physics 2020-03-24 Wei Liu , Su-jie Lin , Hong-bo Hu , Yi-qing Guo , Ai-feng Li

The energy spectra and anisotropies are very important probes of the origin of cosmic rays. Recent measurements show that complicated but very interesting structures exist, at similar energies, in both the spectra and energy-dependent…

High Energy Astrophysical Phenomena · Physics 2023-01-04 Bing-Qiang Qiao , Qing Luo , Qiang Yuan , Yi-Qing Guo

Modern cosmology rests on the working assumption that the Universe is isotropic and homogeneous at large scales. Here, we document a number of anomalous observations pointing to an anisotropic Universe in a direction consistent with the CMB…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-22 Eoin Ó Colgáin

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,…

In this work we present the first results from a new ray-tracing tool to calculate cosmological distances in the context of fully nonlinear general relativity. We use this tool to study the ability of the general cosmographic representation…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-15 Hayley J. Macpherson

In eight years of operation, the Fermi Large Area Telescope (LAT) has detected a large sample of cosmic-ray protons. The LAT's wide field of view and full-sky coverage make it an excellent instrument for studying anisotropy in the arrival…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Matthew Meehan , Justin Vandenbroucke

Deviations from isotropy have been a key tool to identify the origin and the primary type of cosmic rays at low energies. We suggest that the Compton-Getting effect can play a similar role at ultra-high energies: If at these energies the…

Astrophysics · Physics 2007-05-23 M. Kachelriess , P. D. Serpico

The arrival directions of ultrahigh energy cosmic rays (UHECRs) may show anisotropies on all scales, from just above the experimental angular resolution up to medium scales and dipole anisotropies. We find that a global comparison of the…

In addition to shear and vorticity a homogeneous background may also exhibit anisotropic curvature. Here a class of spacetimes is shown to exist where the anisotropy is solely of the latter type, and the shear-free condition is supported by…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-02 Tomi S. Koivisto , David F. Mota , Miguel Quartin , Tom G. Zlosnik

Weak lensing of CMB anisotropies and polarization for the power spectra and higher order statistics can be handled directly in harmonic-space without recourse to real-space correlation functions. For the power spectra, this approach not…

Astrophysics · Physics 2009-10-31 Wayne Hu

The arrival directions of multi-TeV cosmic rays show significant anisotropies at small angular scales. It has been argued that this small scale structure is reflecting the local, turbulent magnetic field in the presence of a global dipole…

High Energy Astrophysical Phenomena · Physics 2015-12-01 Philipp Mertsch , Markus Ahlers

The High-Altitude Water Cherenkov (HAWC) Observatory, located 4100 m above sea level near Sierra Negra (19$^\circ$ N) in Mexico, is sensitive to gamma rays and cosmic rays at TeV energies. The arrival direction distribution of cosmic rays…

High Energy Astrophysical Phenomena · Physics 2019-08-13 S. Y. BenZvi , D. W. Fiorino , S. Westerhoff

We consider the benefits of measuring cosmic statistical anisotropy from redshift-space correlators of the galaxy number density fluctuation and the peculiar velocity field without adopting the plane-parallel (PP) approximation. Since the…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-17 Maresuke Shiraishi , Teppei Okumura , Kazuyuki Akitsu