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Title: R -process Element Cosmic Rays from Neutron Star Mergers

Abstract

Neutron star mergers (NSMs) are one of the most plausible sources of r -process elements in the universe. Therefore, NSMs can also be a major source of ultra-heavy elements in cosmic rays. In this paper, we first estimate the contribution of r -process elements synthesized in NSMs to the ultra-heavy element cosmic rays (UHCRs) by calculating transport equations that take into account energy loss processes and spallations. We show that the flux of UHCRs accelerated by the NSMs themselves fluctuates by many orders of magnitude on a timescale of several million years and can overwhelm UHCRs accelerated by supernova remnants (SNRs) after an NSM takes place within a few kiloparsec from the solar system. Experiments with very long exposure times using meteorites as UHCR detectors can detect this fluctuation. As a consequence, we show that if NSMs are the primary source of UHCRs, future experiments using meteorites may be able to reveal the event history of NSMs in the solar vicinity. We also describe a possible difference in the abundance pattern and energy spectrum of UHCRs between NSM and SNR accelerations.

Authors:
;  [1]
  1. Research Center for the Early Universe, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, 113-0033, Tokyo (Japan)
Publication Date:
OSTI Identifier:
22679856
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 846; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; COSMIC RADIATION; ELEMENT ABUNDANCE; ENERGY LOSSES; ENERGY SPECTRA; FLUCTUATIONS; METEORITES; NEUTRON STARS; NUCLEOSYNTHESIS; R PROCESS; SOLAR SYSTEM; SPALLATION; SUPERNOVA REMNANTS; TRANSPORT THEORY; UNIVERSE

Citation Formats

Komiya, Yutaka, and Shigeyama, Toshikazu. R -process Element Cosmic Rays from Neutron Star Mergers. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA86B3.
Komiya, Yutaka, & Shigeyama, Toshikazu. R -process Element Cosmic Rays from Neutron Star Mergers. United States. doi:10.3847/1538-4357/AA86B3.
Komiya, Yutaka, and Shigeyama, Toshikazu. Sun . "R -process Element Cosmic Rays from Neutron Star Mergers". United States. doi:10.3847/1538-4357/AA86B3.
@article{osti_22679856,
title = {R -process Element Cosmic Rays from Neutron Star Mergers},
author = {Komiya, Yutaka and Shigeyama, Toshikazu},
abstractNote = {Neutron star mergers (NSMs) are one of the most plausible sources of r -process elements in the universe. Therefore, NSMs can also be a major source of ultra-heavy elements in cosmic rays. In this paper, we first estimate the contribution of r -process elements synthesized in NSMs to the ultra-heavy element cosmic rays (UHCRs) by calculating transport equations that take into account energy loss processes and spallations. We show that the flux of UHCRs accelerated by the NSMs themselves fluctuates by many orders of magnitude on a timescale of several million years and can overwhelm UHCRs accelerated by supernova remnants (SNRs) after an NSM takes place within a few kiloparsec from the solar system. Experiments with very long exposure times using meteorites as UHCR detectors can detect this fluctuation. As a consequence, we show that if NSMs are the primary source of UHCRs, future experiments using meteorites may be able to reveal the event history of NSMs in the solar vicinity. We also describe a possible difference in the abundance pattern and energy spectrum of UHCRs between NSM and SNR accelerations.},
doi = {10.3847/1538-4357/AA86B3},
journal = {Astrophysical Journal},
number = 2,
volume = 846,
place = {United States},
year = {Sun Sep 10 00:00:00 EDT 2017},
month = {Sun Sep 10 00:00:00 EDT 2017}
}