EDP Sciences
Free access
Volume 485, Number 1, July I 2008
Page(s) 1 - 4
Section Astrophysical processes
DOI http://dx.doi.org/10.1051/0004-6361:200809468
Published online 06 May 2008

A&A 485, 1-4 (2008)
DOI: 10.1051/0004-6361:200809468

Research Note

Prospects for direct cosmic ray mass measurements through the Gerasimova-Zatsepin effect

S. Lafèbre1, H. Falcke1, 2, J. Hörandel1, and J. Kuijpers1

1  Department of Astrophysics, IMAPP, Radboud University, PO Box 9010, 6500GL Nijmegen, The Netherlands
    e-mail: s.lafebre@astro.ru.nl
2  Radio Observatory, Astron, Dwingeloo, PO Box 2, 7990AA Dwingeloo, The Netherlands

Received 28 January 2008 / Accepted 3 April 2008

Context. The solar radiation field may break ultra-high-energy cosmic nuclei apart, after which both remnants will be deflected in the interplanetary magnetic field in different ways. This process is known as the Gerasimova-Zatsepin effect after its discoverers.
Aims. We investigate the possibility of using the detection of the separated air showers produced by a pair of remnant particles as a way to identify the species of the original cosmic ray primary directly. Event rates for current and proposed detectors are estimated, and requirements are defined for ideal detectors of this phenomenon.
Methods. Detailed computational models of the disintegration and deflection processes for a wide range of cosmic ray primaries in the energy range of 1016 to 1020 eV were combined with sophisticated detector models to calculate realistic detection rates.
Results. The fraction of Gerasimova-Zatsepin events is found to be approximately 10-5 of the cosmic ray flux, implying an intrinsic event rate of around 0.07 km-2 sr-1 yr-1 in the defined energy range. Event rates in any real experiment, whether existing or under construction, will probably not exceed 10-2 yr-1.

Key words: magnetic fields -- ISM: cosmic rays -- radio continuum: general -- acceleration of particles

© ESO 2008