Correlation of the highest-energy cosmic rays with the positions of nearby active galactic nuclei

By J. Abraham, P. Abreu, M. Aglietta, C. Aguirre, D. Allard, I. Allekotte, J. Allen, P. Allison, J. Álvarez-Muñiz, M. Ambrosio and 435 more. 2007

380 citations recorded by the source corpus.

Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the highest energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) \cite{science}. The correlation has maximum significance for cosmic rays with energy greater than ~ 6x10^{19}$ eV and AGN at a distance less than ~ 75 Mpc. We have confirmed the anisotropy at a confidence level of more than 99% through a test with parameters specified {\em a priori}, using an independent data set. The observed correlation is compatible with the hypothesis that cosmic rays with the highest energies originate from extra-galactic sources close enough so that their flux is not significantly attenuated by interaction with the cosmic background radiation (the Greisen-Zatsepin-Kuz'min effect). The angular scale of the correlation observed is a few degrees, which suggests a predominantly light composition unless the magnetic fields are very weak outside the thin disk of our galaxy. Our present data do not identify AGN as the sources of cosmic rays unambiguously, and other candidate sources which are distributed as nearby AGN are not ruled out. We discuss the prospect of unequivocal identification of individual sources of the highest-energy cosmic rays within a few years of continued operation of the Pierre Auger Observatory.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/fa16c010d5a29f3fb385e8ba649ec0661ce516c4

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In Astronomy and Astrophysics

1. E. Orlando
2. Bing Zhang
3. Troy A. Porter
4. Kohta Murase
5. A. Reimer
6. J. Finke
7. C. Dermer
8. Igor V. Moskalenko

In Nuclear and High Energy Physics

1. E. Orlando
2. Kohta Murase
3. Kumiko Kotera
4. Angela V. Olinto
5. Troy A. Porter
6. A. Reimer
7. C. Dermer
8. J. Finke

Citations in the corpus

• The Astrophysics of Ultrahigh-Energy Cosmic Rays (2011, methodology): “In the central region of an AGN for example, assuming equipartition with the magnetic field (corresponding to the Eddington luminosity), for E20 = E/10 20 eV and BG = B/1G, trad ∼ 105sE−120 B −2 G .”
• Hints of the existence of Axion-Like-Particles from the gamma-ray spectra of cosmological sources (2009, neutral): “A, 23, 315 [49] Abraham et al., 2008, Astropart.”
• ROLE OF LINE-OF-SIGHT COSMIC-RAY INTERACTIONS IN FORMING THE SPECTRA OF DISTANT BLAZARS IN TeV GAMMA RAYS AND HIGH-ENERGY NEUTRINOS (2010, background): “…arrival directions of cosmic rays with extragalactic sources because of the effects of the Milky Way magnetic fields (Harari et al. 2000a, 2000b; Abraham et al. 2007, 2008; Golup et al. 2009; Murase & Beacom 2010; Calvez et al. 2010), which are known to have magnitudes as large as several…”
• BLAZARS AS ULTRA-HIGH-ENERGY COSMIC-RAY SOURCES: IMPLICATIONS FOR TeV GAMMA-RAY OBSERVATIONS (2011, background): “…in that the most pronounced excess in arrival directions of UHECRs is positionally centered in the vicinity of the FR-I radio galaxy Centaurus A (Abraham et al. 2008; Abraham et al. 2009).6 FR-I radio galaxies, including their aligned counterparts (BL Lac objects), radiate a volume- and…”
• FERMI LARGE AREA TELESCOPE VIEW OF THE CORE OF THE RADIO GALAXY CENTAURUS A (2010, methodology): “…directions of the highest energy cosmic rays (& 6× 1019 eV) observed by the Auger105 observatory are correlated with nearby AGN, including Cen A (Abraham et al. 2007, 2008), while106 Moskalenko et al. (2009) found that, if the giant lobes are taken into account, as many as four107 ultra-high…”
• Cosmogenic neutrinos: parameter space and detectabilty from PeV to ZeV (2010, methodology): “…of the Greisen-Zatsepin-Kuzmin (GZK) cutoff feature (Greisen, 1966; Zatsepin and Kuzmin, 1966) in the cosmic ray spectrum (Abbasi et al., 2009; Abraham et al., 2008b) and by the indication of anisotropies in the cosmic ray sky distribution at the highest energies (Abraham et al., 2007, 2008a).”