We study the cosmic ray arrival distribution expected from a source of neutrons in the galactic centre at energies around 1 EeV and compare it with the anisotropy detected by AGASA and SUGAR. Besides the point-like signal in the source direction produced by the direct neutrons, an extended signal due to the protons produced in neutron decays is expected. This associated proton signal also leads to an excess in the direction of the spiral arm. For realistic models of the regular and random galactic magnetic fields, the resulting anisotropy as a function of the energy is obtained. We find that for the anisotropy to become sufficiently suppressed below E ∼ 10 17.9 eV, a significant random magnetic field component is required, while on the other hand, this also tends to increase the angular spread of the associated proton signal and to reduce the excess in the spiral arm direction. The source luminosity required in order that the right ascension anisotropy be 4% for the AGASA angular exposure corresponds to a prediction for the point-like flux from direct neutrons compatible with the flux detected by SUGAR. We also analyse the distinguishing features predicted for a large statistics southern observatory.
Bossa, M, Mollerach, S & Roulet, E 2003, 'Decaying neutron propagation in the galaxy and the cosmic ray anisotropy at 1 EeV', Journal of Physics G: Nuclear and Particle Physics, vol. 29, no. 7, pp. 1409-1421. https://doi.org/10.1088/0954-3899/29/7/307
Bossa, M., Mollerach, S., & Roulet, E. (2003). Decaying neutron propagation in the galaxy and the cosmic ray anisotropy at 1 EeV. Journal of Physics G: Nuclear and Particle Physics, 29(7), 1409-1421. https://doi.org/10.1088/0954-3899/29/7/307
@article{5ca15d1381044118bc6439f3c7e77284,
title = "Decaying neutron propagation in the galaxy and the cosmic ray anisotropy at 1 EeV",
abstract = "We study the cosmic ray arrival distribution expected from a source of neutrons in the galactic centre at energies around 1 EeV and compare it with the anisotropy detected by AGASA and SUGAR. Besides the point-like signal in the source direction produced by the direct neutrons, an extended signal due to the protons produced in neutron decays is expected. This associated proton signal also leads to an excess in the direction of the spiral arm. For realistic models of the regular and random galactic magnetic fields, the resulting anisotropy as a function of the energy is obtained. We find that for the anisotropy to become sufficiently suppressed below E ∼ 10 17.9 eV, a significant random magnetic field component is required, while on the other hand, this also tends to increase the angular spread of the associated proton signal and to reduce the excess in the spiral arm direction. The source luminosity required in order that the right ascension anisotropy be 4% for the AGASA angular exposure corresponds to a prediction for the point-like flux from direct neutrons compatible with the flux detected by SUGAR. We also analyse the distinguishing features predicted for a large statistics southern observatory.",
author = "Mat{\'i}as Bossa and Silvia Mollerach and Esteban Roulet",
year = "2003",
month = jul,
day = "1",
doi = "10.1088/0954-3899/29/7/307",
language = "English",
volume = "29",
pages = "1409--1421",
journal = "Journal of Physics G: Nuclear and Particle Physics",
issn = "0954-3899",
publisher = "IOP Publishing Ltd.",
number = "7",
}