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Title: Ultrahigh energy cosmic ray nuclei from extragalactic pulsars and the effect of their Galactic counterparts

Abstract

The acceleration of ultrahigh energy nuclei in fast spinning newborn pulsars can explain the observed spectrum of ultrahigh energy cosmic rays and the trend towards heavier nuclei for energies above 10{sup 19} eV as reported by the Auger Observatory. Pulsar acceleration implies a hard injection spectrum ( ∼ E{sup −1}) due to pulsar spin down and a maximum energy E{sub max} ∼ Z 10{sup 19} eV due to the limit on the spin rate of neutron stars. We have previously shown that the escape through the young supernova remnant softens the spectrum, decreases slightly the maximum energy, and generates secondary nuclei. Here we show that the distribution of pulsar birth periods and the effect of propagation in the interstellar and intergalactic media modifies the combined spectrum of all pulsars. By assuming a normal distribution of pulsar birth periods centered at 300 ms, we show that the contribution of extragalactic pulsar births to the ultrahigh energy cosmic ray spectrum naturally gives rise to a contribution to very high energy cosmic rays (VHECRs, between 10{sup 16} and 10{sup 18} eV) by Galactic pulsar births. The required injected composition to fit the observed spectrum depends on the absolute energy scale, which is uncertain,more » differing between Auger Observatory and Telescope Array. The contribution of Galactic pulsar births can also bridge the gap between predictions for cosmic ray acceleration in supernova remnants and the observed spectrum just below the ankle, depending on the composition of the cosmic rays that escape the supernova remnant and the diffusion behavior of VHECRs in the Galaxy.« less

Authors:
;  [1];  [2]
  1. Department of Astronomy and Astrophysics, Kavli Institute for Cosmological Physics, The University of Chicago, Chicago, Illinois 60637 (United States)
  2. Institut d'Astrophysique de Paris, UMR 7095 - CNRS, Université Pierre and Marie Curie, 98 bis boulevard Arago, 75014, Paris (France)
Publication Date:
OSTI Identifier:
22282948
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2013; Journal Issue: 03; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; COSMIC NUCLEI; ENERGY SPECTRA; GALAXIES; HEAVY NUCLEI; NEUTRON STARS; PULSARS; SPIN; SUPERNOVA REMNANTS; TELESCOPES

Citation Formats

Fang, Ke, Olinto, Angela V., and Kotera, Kumiko. Ultrahigh energy cosmic ray nuclei from extragalactic pulsars and the effect of their Galactic counterparts. United States: N. p., 2013. Web. doi:10.1088/1475-7516/2013/03/010.
Fang, Ke, Olinto, Angela V., & Kotera, Kumiko. Ultrahigh energy cosmic ray nuclei from extragalactic pulsars and the effect of their Galactic counterparts. United States. https://doi.org/10.1088/1475-7516/2013/03/010
Fang, Ke, Olinto, Angela V., and Kotera, Kumiko. Fri . "Ultrahigh energy cosmic ray nuclei from extragalactic pulsars and the effect of their Galactic counterparts". United States. https://doi.org/10.1088/1475-7516/2013/03/010.
@article{osti_22282948,
title = {Ultrahigh energy cosmic ray nuclei from extragalactic pulsars and the effect of their Galactic counterparts},
author = {Fang, Ke and Olinto, Angela V. and Kotera, Kumiko},
abstractNote = {The acceleration of ultrahigh energy nuclei in fast spinning newborn pulsars can explain the observed spectrum of ultrahigh energy cosmic rays and the trend towards heavier nuclei for energies above 10{sup 19} eV as reported by the Auger Observatory. Pulsar acceleration implies a hard injection spectrum ( ∼ E{sup −1}) due to pulsar spin down and a maximum energy E{sub max} ∼ Z 10{sup 19} eV due to the limit on the spin rate of neutron stars. We have previously shown that the escape through the young supernova remnant softens the spectrum, decreases slightly the maximum energy, and generates secondary nuclei. Here we show that the distribution of pulsar birth periods and the effect of propagation in the interstellar and intergalactic media modifies the combined spectrum of all pulsars. By assuming a normal distribution of pulsar birth periods centered at 300 ms, we show that the contribution of extragalactic pulsar births to the ultrahigh energy cosmic ray spectrum naturally gives rise to a contribution to very high energy cosmic rays (VHECRs, between 10{sup 16} and 10{sup 18} eV) by Galactic pulsar births. The required injected composition to fit the observed spectrum depends on the absolute energy scale, which is uncertain, differing between Auger Observatory and Telescope Array. The contribution of Galactic pulsar births can also bridge the gap between predictions for cosmic ray acceleration in supernova remnants and the observed spectrum just below the ankle, depending on the composition of the cosmic rays that escape the supernova remnant and the diffusion behavior of VHECRs in the Galaxy.},
doi = {10.1088/1475-7516/2013/03/010},
url = {https://www.osti.gov/biblio/22282948}, journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 03,
volume = 2013,
place = {United States},
year = {2013},
month = {3}
}