Large- and Medium-Scale Anisotropies in the Arrival Directions of Cosmic Rays observed with KASCADE-Grande
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Large- and Medium-Scale Anisotropies in the Arrival Directions of Cosmic Rays observed with KASCADE-Grande. / Ahlers, Markus.
I: Astrophysics Journal Letters, Bind 886, Nr. 1, L18, 19.09.2019.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Large- and Medium-Scale Anisotropies in the Arrival Directions of Cosmic Rays observed with KASCADE-Grande
AU - Ahlers, Markus
N1 - 6 pages, 4 figures
PY - 2019/9/19
Y1 - 2019/9/19
N2 - We search for anisotropies in the arrival directions of cosmic rays observed by the KASCADE-Grande air shower experiment. The analysis is based on public data of about 23.7 million events with reconstructed primary energies above 1 PeV. We apply a novel maximum-likelihood reconstruction method for the cosmic ray anisotropy, that compensates for spurious anisotropies induced by local detector effects. We find no evidence for a large-scale dipole anisotropy in the data, consistent with official results based on the conventional East-West derivative method. On the other hand, a subset of cosmic rays with median energy of 33 PeV shows strong evidence for a medium-scale feature with an angular diameter of 40 degrees. After accounting for the look-elsewhere effect, the post-trial significance of this medium-scale feature is at the level of 4sigma.
AB - We search for anisotropies in the arrival directions of cosmic rays observed by the KASCADE-Grande air shower experiment. The analysis is based on public data of about 23.7 million events with reconstructed primary energies above 1 PeV. We apply a novel maximum-likelihood reconstruction method for the cosmic ray anisotropy, that compensates for spurious anisotropies induced by local detector effects. We find no evidence for a large-scale dipole anisotropy in the data, consistent with official results based on the conventional East-West derivative method. On the other hand, a subset of cosmic rays with median energy of 33 PeV shows strong evidence for a medium-scale feature with an angular diameter of 40 degrees. After accounting for the look-elsewhere effect, the post-trial significance of this medium-scale feature is at the level of 4sigma.
KW - astro-ph.HE
KW - hep-ex
KW - hep-ph
U2 - 10.3847/2041-8213/ab552f
DO - 10.3847/2041-8213/ab552f
M3 - Journal article
VL - 886
JO - The Astrophysical Journal Letters
JF - The Astrophysical Journal Letters
SN - 2041-8205
IS - 1
M1 - L18
ER -
ID: 230898696