Comment on Correlation of the Highest-Energy Cosmic Rays with Nearby Extragalactic Objects.pdf
文本预览下载声明
a
r
X
i
v
:
0
7
1
1
.4
0
6
0
v
1
[
a
s
t
r
o
-
p
h
]
2
6
N
o
v
2
0
0
7
Comment on “Correlation of the Highest-Energy
Cosmic Rays with Nearby Extragalactic Objects”
Dmitry Gorbunov,
1
Peter Tinyakov,
1,2
Igor Tkachev,
1
Sergey Troitsky
1?
1
Institute for Nuclear Research of the Russian Academy of Sciences,
60th October Anniversary Prospect 7a, 117312, Moscow, Russia
2
Service de Physique The?orique, Universite? Libre de Bruxelles,
CP225, blv. du Triomphe, B-1050, Bruxelles, Belgium
?
E-mail: st@ms2.inr.ac.ru
We argue that the data published by the Pierre Auger Collaboration
(arXiv:0711.2256) disfavor at 99% confidence level their hypothesis that most
of the highest-energy cosmic rays are protons from nearby astrophysical
sources, either Active Galactic Nuclei or other objects with a similar spatial
distribution.
The Pierre Auger Collaboration reported a remarkable correlation (1) between the arrival
directions of ultra-high energy cosmic rays (UHECR) and positions of nearby Active Galactic
Nuclei (AGN). The correlation was found by scanning over the maximum angular separation,
the minimum event energy and the maximum AGN redshift, see Ref. (2) for the details of the
method. The best signal was found at the angle of 3.1
?
for the cosmic-ray set consisting of 15
events with reconstructed energies E 5.6 × 1019 eV and for the set of 472 AGN obtained by
imposing the cut on the redshift, z ≤ 0.018, in the catalog (3). The correlation was tested with
the independent set consisting of 13 events, with the parameters fixed a priori from the first
1
data set. The probability that the correlation has occurred by chance is 1.7 × 10?3 as derived
from the independent set. The conclusion was made that the anisotropy of arrival directions is
consistent with the hypothesis that “most of the cosmic rays reaching Earth in that energy range
are protons from nearby astrophysical sources, either AGN or other objects with a similar spatial
distribution.” We refer to this propositio
显示全部