Ultra-high energy cosmic rays detected by Auger and AGASA

Nagar, Neil M.; Matulich, Javier

doi:10.1051/0004-6361/200912702

Cited by 12 publications

(13 citation statements)

References 46 publications

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“…[221] (Ref. [222]) reports a correlation between these 27 UHECR directions and the locations of spiral galaxies (extended nearby radiogalaxies) by using the HIPASS Catalogue (several catalogues).…”

Section: The Uhecrs Directions Are Clustered and Correlated With The mentioning

confidence: 99%

Cosmic rays and the search for a Lorentz Invariance Violation

Bietenholz

2011

Physics Reports

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This is an introductory review about the on-going search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We discuss the Greisen-Zatsepin-Kuz'min (GZK) energy cutoff for cosmic protons, which is predicted due to photopion production in the Cosmic Microwave Background (CMB). This is a process of modest energy in the proton rest frame. It can be investigated to a high precision in the laboratory, if Lorentz transformations apply even at factors γ ∼ O(10 11 ). For heavier nuclei the energy attenuation is even faster due to photo-disintegration, again if this process is Lorentz invariant. Hence the viability of Lorentz symmetry up to tremendous γ-factors -far beyond accelerator tests -is a central issue.Next we comment on conceptual aspects of Lorentz Invariance and the possibility of its spontaneous breaking. This could lead to slightly particle dependent "Maximal Attainable Velocities". We discuss their effect in decays, Cerenkov radiation, the GZK cutoff and neutrino oscillation in cosmic rays.We also review the search for LIV in cosmic γ-rays. For multi TeV γ-rays we possibly encounter another puzzle related to the transparency of the CMB, similar to the GZK cutoff, due to electron/positron creation and subsequent inverse Compton scattering. The photons emitted in a Gamma Ray Burst occur at lower energies, but their very long path provides access to information not far from the Planck scale. We discuss conceivable non-linear photon dispersions based on non-commutative geometry or effective approaches.No LIV has been observed so far. However, even extremely tiny LIV effects could change the predictions for cosmic ray physics drastically.An Appendix is devoted to the recent hypothesis by the Pierre Auger Collaboration, which identifies nearby Active Galactic Nuclei -or objects next to them -as probable UHECR sources.

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Section: The Uhecrs Directions Are Clustered and Correlated With The mentioning

confidence: 99%

Cosmic rays and the search for a Lorentz Invariance Violation

Bietenholz

2011

Physics Reports

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“…Han et al 2006;Sun et al 2008) and are widely discussed in the studies of UHECR origin (e.g. Stanev 1997;Prouza & Šmída 2003;Nagar & Matulich 2009). Kachelrieß et al (2007) concluded that the deflections of UHECRs by the GMFs cannot be neglected even for the protons of E = 10 20 eV, since the deflection angles are comparable with the angular resolution of current experiments.…”

Section: Introductionmentioning

confidence: 95%

DO ULTRAHIGH ENERGY COSMIC RAYS COME FROM ACTIVE GALACTIC NUCLEI ANDFERMIγ-RAY SOURCES?

Jiang

Hou

Han

et al. 2010

ApJ

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We study possible correlations between ultrahigh energy cosmic rays (UHECRs), observed by Auger, AGASA, and Yakutsk, and nearby active galactic nuclei (AGNs) and F ermi sources. We consider the deflection effects by a Galactic magnetic field (GMF) model constrained by the most updated measurements. We found that the average deflection angles of UHECRs by the Galactic magnetic fields are less than 4 • . A correlation between the Auger cosmic-ray events and nearby AGNs with a significance level of ∼ 4σ was found for the Auger UHECR data sets with or without deflection correction. No correlation was found between the AGASA/Yakutsk events with nearby AGNs. Marginal correlations between the Auger events and the F ermi sources, and between AGASA events and F ermi AGNs were found when the deflections calculated by the GMF model were considered. However, no correlation was found between the Yakutsk data and F ermi sources. Some F ermi sources are close to the arrival directions of UHECR events detected by Auger, AGASA, and Yakutsk, most of which are probably chance coincidence rather than objects producing UHECRs in the nearby Universe. Four F ermi sources, NGC 4945, ESO 323-G77, NGC 6951, and Cen A, within 100 Mpc have UHECR events within 3 • . 1 from their positions, which could potentially be cosmic-ray accelerators. However, the association can only be confirmed if more UHECRs are preferably detected in these directions Subject headings: (ISM:) cosmic rays -galaxies: active -magnetic field -methods: statistical

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“…Hardcastle et al argue the possibility that the giant radio lobes of Cen A can accelerate UHECRs [12]. Related works include [13,14,15,16,17,18,19]. Ref.…”

Section: Introductionmentioning

confidence: 99%

Magnetic deflections of ultra-high energy cosmic rays from Centaurus A

Keivani

Farrar

Sutherland

2015

Astroparticle Physics

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We present the results of a study that simulates trajectories of ultra-high energy cosmic rays from Centaurus A to Earth, for particle rigidities from E/Z = 2 EV to 100 EV, i.e., covering the possibility of primary particles as heavy as Fe nuclei with energies exceeding 50 EeV. The Galactic magnetic field is modeled using the recent work of Jansson and Farrar (JF12) which fitted its parameters to match extragalactic Faraday rotation measures and WMAP7 synchrotron emission maps. We include the random component of the GMF using the JF12 3D model for B rand ( r) and explore the impact of different random realizations, coherence length and other features on cosmic ray deflections. Gross aspects of the arrival direction distribution such as mean deflection and the RMS dispersion depend mainly on rigidity and differ relatively little from one realization to another. However different realizations exhibit non-trivial substructure whose specific features vary considerably from one realization to another, especially for lower rigidities. At the lowest rigidity of 2 EV, the distribution is broad enough that it might be compatible with a scenario in which Cen A is the principle source of all UHECRs. No attempt is made here to formulate a robust test of this possibility, although some challenges to such a scenario are noted.

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Ultra-high energy cosmic rays detected by Auger and AGASA

Cited by 12 publications

References 46 publications

Cosmic rays and the search for a Lorentz Invariance Violation

Cosmic rays and the search for a Lorentz Invariance Violation

DO ULTRAHIGH ENERGY COSMIC RAYS COME FROM ACTIVE GALACTIC NUCLEI ANDFERMIγ-RAY SOURCES?

Magnetic deflections of ultra-high energy cosmic rays from Centaurus A

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