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A search for anisotropy in the arrival directions of ultra high energy cosmic rays recorded at the Pierre Auger Observatory
Published on Apr 30, 2012in Journal of Cosmology and Astroparticle Physics 5.13
· DOI :10.1088/1475-7516/2012/04/040
P. Abreu44
Estimated H-index: 44
(Technical University of Lisbon),
M. Aglietta36
Estimated H-index: 36
(University of Turin)
+ 498 AuthorsMichael Ziolkowski71
Estimated H-index: 71
(Folkwang University of the Arts)
Abstract
Observations of cosmic rays arrival directions made with the Pierre Auger Observatory have previously provided evidence of anisotropy at the 99% CL using the correlation of ultra high energy cosmic rays (UHECRs) with objects drawn from the Veron-Cetty Veron catalog. In this paper we report on the use of three catalog independent methods to search for anisotropy. The 2pt-L, 2pt+ and 3pt methods, each giving a different measure of self-clustering in arrival directions, were tested on mock cosmic ray data sets to study the impacts of sample size and magnetic smearing on their results, accounting for both angular and energy resolutions. If the sources of UHECRs follow the same large scale structure as ordinary galaxies in the local Universe and if UHECRs are deflected no more than a few degrees, a study of mock maps suggests that these three method can efficiently respond to the resulting anisotropy with a P-value = 1.0% or smaller with data sets as few as 100 events. using data taken from January 1, 2004 to July 31, 2010 we examined the 20, 30, ... , 110 highest energy events with a corresponding minimum energy threshold of about 49.3 EeV. The minimum P-values found were 13.5% using the 2pt-L method, 1.0% using the 2pt+ method and 1.1% using the 3pt method for the highest 100 energy events. In view of the multiple (correlated) scans performed on the data set, these catalog-independent methods do not yield strong evidence of anisotropy in the highest energy cosmic rays.
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References30
Published on Jan 1, 1982in Space Science Reviews 9.33
P. J. E. Peebles52
Estimated H-index: 52
,
Giora Shaviv1
Estimated H-index: 1
3,619 Citations
Published on Dec 1, 2010in Astroparticle Physics 3.20
M. Aglietta36
Estimated H-index: 36
(University of Turin),
D. Allard2
Estimated H-index: 2
(University of Paris-Sud)
+ 1 AuthorsJeffrey C. Allen65
Estimated H-index: 65
(New York University)
Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, 6 x 10(19) eV. The anisotropy was measured by the fraction of arrival directions that are less than 3.1 degrees from the position of an active galactic nucleus within 75 Mpc (using the Veron-Cetty and Veron 12th catalog). An updated measurement of this fraction is reported here using the arrival directio...
220 Citations Source Cite
Published on Dec 18, 2011in arXiv: High Energy Astrophysical Phenomena
A. Berlind1
Estimated H-index: 1
,
N. Busca1
Estimated H-index: 1
+ 1 AuthorsJ. P. Roberts1
Estimated H-index: 1
We provide realistic mock-catalogs of cosmic rays above 40 EeV, for a pure proton composition, assuming their sources are a random subset of ordinary galaxies in a simulated, volume-limited survey, for various choices of source density: 10^-3.5 Mpc^-3, 10^-4.0 Mpc^-3 and 10^-4.5 Mpc^-3. The spectrum at the source is taken to be E^-2.3 and the effects of cosmological redshifting as well as photo-pion and e^+ e^- energy losses are included.
3 Citations
Published on Jan 1, 1966in Jetp Letters 1.36
G.T. Zatsepin1
Estimated H-index: 1
,
V.A. Kuzmin1
Estimated H-index: 1
357 Citations
R. Abbasi41
Estimated H-index: 41
,
Charles C. H. Jui1
Estimated H-index: 1
In this paper we investigate the possible existence of multi-point correlation in the arrival direction of the UHECR events detected by the High Resolution Fly's Eye (HiRes) stereo detector. Multi-point correlations could result from the de- flection of UHECRs by galactic and intergalactic magnetic fields, and the subsequent dispersion of arrival directions from point like sources. The search is performed by calculating the solid angle subtended by the polygon between triplets and quadruplets of...
1 Citations
Published on Apr 22, 2002in The Astrophysical Journal 6.63
D. S. Gorbunov28
Estimated H-index: 28
,
I. Tkachev34
Estimated H-index: 34
+ 1 AuthorsP. Tinyakov27
Estimated H-index: 27
9 Citations
Published on Aug 4, 2008in Physical Review Letters 8.84
J. Abraham6
Estimated H-index: 6
,
P. Abreu44
Estimated H-index: 44
+ 454 AuthorsM. Ambrosio30
Estimated H-index: 30
373 Citations Source Cite
Published on Apr 1, 2008in Astroparticle Physics 3.20
J. Abraham6
Estimated H-index: 6
,
P. Abreu44
Estimated H-index: 44
+ 443 AuthorsM. Ambrosio30
Estimated H-index: 30
Abstract 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) [Pierre Auger Collaboration, Science 318 (2007) 938]. The correlation has maximum significance for cosmic rays with energy greater than ∼6 × 10 19 eV and AGN at a distance less than ∼75 Mpc. We have confirmed the anisotropy at a confidence level of m...
267 Citations Source Cite
Published on Nov 1, 2008in Astroparticle Physics 3.20
R. Abbasi41
Estimated H-index: 41
(University of Utah),
T. Abu-Zayyad24
Estimated H-index: 24
(University of Utah)
+ 62 AuthorsS. A. Blake19
Estimated H-index: 19
(University of Utah)
Abstract We have searched for correlations between the pointing directions of ultrahigh energy cosmic rays observed by the High Resolution Fly’s Eye experiment and active galactic nuclei (AGN) visible from its northern hemisphere location. No correlations, other than random correlations, have been found. We report our results using search parameters prescribed by the Pierre Auger collaboration. Using these parameters, the Auger collaboration concludes that a positive correlation exists for sourc...
101 Citations Source Cite
Published on Feb 15, 1963in Physical Review Letters 8.84
John Linsley8
Estimated H-index: 8
(Massachusetts Institute of Technology)
Relations and assumptions used in estimating the size of a cosmic air shower recorded at the MIT Volcano Ranch station are discussed. The total number of particles produced is estimated as 5 x 10/sup 10/, and the total energy of the primary particle is estimated as 1.0 x 10/sup 20/ ev, indicating its origin outside our galaxy. (D.C.W.)
239 Citations Source Cite
Cited By6
Published on Jun 1, 2015in European Physical Journal C 5.17
A. Aab19
Estimated H-index: 19
(Folkwang University of the Arts),
P. Abreu44
Estimated H-index: 44
(University of Lisbon)
+ 483 AuthorsA. Almela23
Estimated H-index: 23
(National Scientific and Technical Research Council)
Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with E >= 6 x 10(19) eV by analyzing cosmic rays with energies above E >= 5 x 10(18) eV arriving within an angular separation of approximately 15 degrees. We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correl...
1 Citations Source Cite
Published on Sep 21, 2014in Classical and Quantum Gravity 3.28
Ilya L. Shapiro3
Estimated H-index: 3
(Tomsk State Pedagogical University),
Poliane M. Teixeira2
Estimated H-index: 2
The Holst term represents an interesting addition to the Einstein–Cartan theory of gravity with torsion. When this term is present the contact interactions between vector and axial vector fermion currents gain an extra parity-violating component. We re-derive this interaction using a simple representation for the Holst term. The same representation serves as a useful basis for the calculation of one-loop divergences in the theory with external fermionic currents and cosmological constant. Furthe...
5 Citations Source Cite
Published on Jul 18, 2016in Proceedings of SPIE
Paolo Soffitta41
Estimated H-index: 41
,
R. Bellazzini32
Estimated H-index: 32
(University of Pisa)
+ 418 AuthorsR. Goosmann1
Estimated H-index: 1
(University of Strasbourg)
XIPE, the X-ray Imaging Polarimetry Explorer, is a mission dedicated to X-ray Astronomy. At the time of writing XIPE is in a competitive phase A as fourth medium size mission of ESA (M4). It promises to reopen the polarimetry window in high energy Astrophysics after more than 4 decades thanks to a detector that efficiently exploits the photoelectric effect and to X-ray optics with large effective area. XIPE uniqueness is time-spectrally-spatially- resolved X-ray polarimetry as a breakthrough in ...
125 Citations Source Cite
Published on Jan 1, 2014
L. Gonzalez-Mestres1
Estimated H-index: 1
(University of Savoy)
Detailed analyses of WMAP and Planck data can have significant implications for noncyclic pre-Big Bang approaches incorporating a new fundamental scale beyond the Planck scale and, potentially, new ultimate constituents of matter with unconventional basic properties as compared to standard particles. Cosmic-ray experiments at the highest energies can also yield relevant information. Hopefully, future studies will be able to deal with alternatives: i) to standard physics for the structure of the ...
6 Citations Source Cite
Published on Jan 1, 2014
Luis Gonzalez-Mestres11
Estimated H-index: 11
(University of Savoy)
With the present understanding of data, the observed flux suppression for ultra-high energy cosmic rays (UHECR) at energies above 4.10E19 eV can be a signature of the Greisen-Zatsepin-Kuzmin (GZK) cutoff or be related to a similar mechanism. But it may also correspond, for instance, to the maximum energies available at the relevant sources. In both cases, violations of special relativity modifying cosmic-ray propagation or acceleration at very high energy can potentially play a role. Other viola...
12 Citations Source Cite
Published on Dec 1, 2013in Experimental Astronomy 1.35
Paolo Soffitta41
Estimated H-index: 41
(INAF),
Xavier Barcons36
Estimated H-index: 36
(Spanish National Research Council)
+ 96 AuthorsM. Pearce25
Estimated H-index: 25
(Royal Institute of Technology)
X-ray polarimetry, sometimes alone, and sometimes coupled to spectral and temporal variability measurements and to imaging, allows a wealth of physical phenomena in astrophysics to be studied. X-ra ...
62 Citations Source Cite
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