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Title: A self-consistent model of cosmic-ray fluxes and positron excess: roles of nearby pulsars and a sub-dominant source population

Abstract

The cosmic-ray positron flux calculated using the cosmic-ray nuclei interactions in our Galaxy cannot explain observed data above 10 GeV. An excess in the measured positron flux is therefore open to interpretation. Nearby pulsars, located within sub-kiloparsec range of the Solar system, are often invoked as plausible sources contributing to the excess. We show that an additional, sub-dominant population of sources together with the contributions from a few nearby pulsars can explain the latest positron excess data from the Alpha Magnetic Spectrometer (AMS). We simultaneously model, using the DRAGON code, propagation of cosmic-ray proton, Helium, electron and positron and fit their respective flux data. Our fit to the Boron to Carbon ratio data gives a diffusion spectral index of 0.45, which is close to the Kraichnan turbulent spectrum.

Authors:
;  [1]
  1. Department of Physics, University of Johannesburg, P. O. Box 524, Auckland Park 2006 (South Africa)
Publication Date:
OSTI Identifier:
22667680
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2017; Journal Issue: 09; 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; BORON; CARBON; CONCENTRATION RATIO; COSMIC RADIATION; COSMIC RAY FLUX; DIFFUSION; ELECTRONS; GALAXIES; GEV RANGE; HELIUM; INTERACTIONS; MAGNETIC SPECTROMETERS; NUCLEI; POSITRONS; PROTONS; PULSARS; SOLAR SYSTEM; SPECTRA

Citation Formats

Joshi, Jagdish C., and Razzaque, Soebur, E-mail: jjagdish@uj.ac.za, E-mail: srazzaque@uj.ac.za. A self-consistent model of cosmic-ray fluxes and positron excess: roles of nearby pulsars and a sub-dominant source population. United States: N. p., 2017. Web. doi:10.1088/1475-7516/2017/09/029.
Joshi, Jagdish C., & Razzaque, Soebur, E-mail: jjagdish@uj.ac.za, E-mail: srazzaque@uj.ac.za. A self-consistent model of cosmic-ray fluxes and positron excess: roles of nearby pulsars and a sub-dominant source population. United States. doi:10.1088/1475-7516/2017/09/029.
Joshi, Jagdish C., and Razzaque, Soebur, E-mail: jjagdish@uj.ac.za, E-mail: srazzaque@uj.ac.za. Fri . "A self-consistent model of cosmic-ray fluxes and positron excess: roles of nearby pulsars and a sub-dominant source population". United States. doi:10.1088/1475-7516/2017/09/029.
@article{osti_22667680,
title = {A self-consistent model of cosmic-ray fluxes and positron excess: roles of nearby pulsars and a sub-dominant source population},
author = {Joshi, Jagdish C. and Razzaque, Soebur, E-mail: jjagdish@uj.ac.za, E-mail: srazzaque@uj.ac.za},
abstractNote = {The cosmic-ray positron flux calculated using the cosmic-ray nuclei interactions in our Galaxy cannot explain observed data above 10 GeV. An excess in the measured positron flux is therefore open to interpretation. Nearby pulsars, located within sub-kiloparsec range of the Solar system, are often invoked as plausible sources contributing to the excess. We show that an additional, sub-dominant population of sources together with the contributions from a few nearby pulsars can explain the latest positron excess data from the Alpha Magnetic Spectrometer (AMS). We simultaneously model, using the DRAGON code, propagation of cosmic-ray proton, Helium, electron and positron and fit their respective flux data. Our fit to the Boron to Carbon ratio data gives a diffusion spectral index of 0.45, which is close to the Kraichnan turbulent spectrum.},
doi = {10.1088/1475-7516/2017/09/029},
journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 09,
volume = 2017,
place = {United States},
year = {2017},
month = {9}
}