Contribution of Pion Production by Primary Cosmic-Ray Nucleons to the Interstellar Electron-Positron Flux

1973 ◽  
Vol 7 (5) ◽  
pp. 1406-1411 ◽  
Author(s):  
John Dooher
Keyword(s):  
Pion Production ◽  
Cosmic Ray ◽  
Electron Positron ◽  
Positron Flux

scholarly journals Dissecting cosmic-ray electron-positron data with Occam’s razor: the role of known pulsars

Open Physics ◽  
2012 ◽  
Vol 10 (1) ◽  
pp. 1-31 ◽  
Author(s):  
Stefano Profumo
Keyword(s):  
Gamma Ray ◽  
Decisive Role ◽  
Cosmic Ray ◽  
High Energy ◽  
Current Data ◽  
Energy Output ◽  
Total Electron ◽  
Positron Fraction ◽  
Electron Positron ◽  
Positron Flux

AbstractWe argue that both the positron fraction measured by PAMELA and the peculiar spectral features reported in the total electron-positron flux measured by ATIC have a very natural explanation in electron-positron pairs produced by nearby pulsars. While this possibility was pointed out a long time ago, the greatly improved quality of current data potentially allow to reverse-engineer the problem: given the regions of pulsar parameter space favored by PAMELA and by ATIC, are there known pulsars that explain the data with reasonable assumptions on the injected electron-positron pairs? In the context of simple benchmark models for estimating the electron-positron output, we consider all known pulsars, as listed in the most complete available catalogue. We find that it is unlikely that a single pulsar be responsible for both the PAMELA positron fraction anomaly and for the ATIC excess, although two single sources are in principle enough to explain both experimental results. The PAMELA excess positrons likely come from a set of mature pulsars (age ∼ × 106 yr), with a distance of 0.8–1 kpc, or from a single, younger and closer source like Geminga. The ATIC data require a larger (and less plausible) energy output, and favor an origin associated to powerful, more distant (1–2 kpc) and younger (age ∼ × 5 × 105 yr) pulsars. We list several candidate pulsars that can individually or coherently contribute to explain the PAMELA and ATIC data. Although generally suppressed, we find that the contribution of pulsars more distant than 1–2 kpc could contribute for the ATIC excess. Finally, we stress the multi-faceted and decisive role that Fermi-LAT will play in the very near future by (1) providing us with an exquisite measurement of the electron-positron flux, (2) unveiling the existence of as yet undetected gamma-ray pulsars, and (3) searching for anisotropies in the arrival direction of high-energy electrons and positrons.

scholarly journals Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

2019 ◽  
Vol 209 ◽  
pp. 01007
Author(s):  
Francesco Nozzoli
Keyword(s):  
Electron Flux ◽  
Space Station ◽  
Cosmic Ray ◽  
High Energy ◽  
Precision Measurements ◽  
High Energy Electrons ◽  
Electrons And Positrons ◽  
Positron Flux ◽  
Rigidity Dependence ◽  
Alpha Magnetic Spectrometer

Precision measurements by AMS of the fluxes of cosmic ray positrons, electrons, antiprotons, protons as well as their rations reveal several unexpected and intriguing features. The presented measurements extend the energy range of the previous observations with much increased precision. The new results show that the behavior of positron flux at around 300 GeV is consistent with a new source that produce equal amount of high energy electrons and positrons. In addition, in the absolute rigidity range 60–500 GV, the antiproton, proton, and positron fluxes are found to have nearly identical rigidity dependence and the electron flux exhibits different rigidity dependence.

scholarly journals Implications of a possible TeV break in the cosmic-ray electron and positron flux

2021 ◽  
Vol 103 (11) ◽  
Author(s):  
Yu-Chen Ding ◽  
Nan Li ◽  
Chun-Cheng Wei ◽  
Yue-Liang Wu ◽  
Yu-Feng Zhou
Keyword(s):  
Cosmic Ray ◽  
Positron Flux

scholarly journals IS COSMIC RAY ELECTRON EXCESS FROM PULSARS SPIKY OR SMOOTH?: CONTINUOUS AND MULTIPLE ELECTRON/POSITRON INJECTIONS

2010 ◽  
Vol 710 (2) ◽  
pp. 958-963 ◽  
Author(s):  
Norita Kawanaka ◽  
Kunihito Ioka ◽  
Mihoko M. Nojiri
Keyword(s):  
Cosmic Ray ◽  
Electron Positron

Electron-positron flux at the surface of the pulsar in the Crab

Nature ◽  
1977 ◽  
Vol 267 (5613) ◽  
pp. 686-687 ◽  
Author(s):  
C. M. VARMA
Keyword(s):  
Electron Positron ◽  
Positron Flux

scholarly journals Cosmic-ray ionisation in circumstellar discs

2018 ◽  
Vol 614 ◽  
pp. A111 ◽  
Author(s):  
Marco Padovani ◽  
Alexei V. Ivlev ◽  
Daniele Galli ◽  
Paola Caselli
Keyword(s):  
Molecular Clouds ◽  
Column Density ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Charged Dust ◽  
Interstellar Gas ◽  
Complex Behaviour ◽  
Electron Positron ◽  
Fractional Abundance ◽  
Ionisation Rate

Context. Galactic cosmic rays (CRs) are a ubiquitous source of ionisation of the interstellar gas, competing with UV and X-ray photons as well as natural radioactivity in determining the fractional abundance of electrons, ions, and charged dust grains in molecular clouds and circumstellar discs. Aims. We model the propagation of various components of Galactic CRs versus the column density of the gas. Our study is focussed on the propagation at high densities, above a few g cm−2, especially relevant for the inner regions of collapsing clouds and circumstellar discs. Methods. The propagation of primary and secondary CR particles (protons and heavier nuclei, electrons, positrons, and photons) is computed in the continuous slowing down approximation, diffusion approximation, or catastrophic approximation by adopting a matching procedure for the various transport regimes. A choice of the proper regime depends on the nature of the dominant loss process modelled as continuous or catastrophic. Results. The CR ionisation rate is determined by CR protons and their secondary electrons below ≈130 g cm−2 and by electron-positron pairs created by photon decay above ≈600 g cm−2. We show that a proper description of the particle transport is essential to compute the ionisation rate in the latter case, since the electron and positron differential fluxes depend sensitively on the fluxes of both protons and photons. Conclusions. Our results show that the CR ionisation rate in high-density environments, such as the inner parts of collapsing molecular clouds or the mid-plane of circumstellar discs, is higher than previously assumed. It does not decline exponentially with increasing column density, but follows a more complex behaviour because of the interplay of the different processes governing the generation and propagation of secondary particles.

scholarly journals ELECTRON/POSITRON EXCESSES IN THE COSMIC RAY SPECTRUM AND POSSIBLE INTERPRETATIONS

2010 ◽  
Vol 19 (13) ◽  
pp. 2011-2058 ◽  
Author(s):  
YI-ZHONG FAN ◽  
BING ZHANG ◽  
JIN CHANG
Keyword(s):  
Dark Matter ◽  
Supernova Remnant ◽  
Cosmic Ray ◽  
Theoretical Models ◽  
New Physics ◽  
Observational Constraints ◽  
Correct Interpretation ◽  
Observational Feature ◽  
Electron Positron ◽  
Observational Status

The data collected by ATIC, PPB-BETS, FERMI-LAT and HESS all indicate that there is an electron/positron excess in the cosmic ray energy spectrum above ~100 GeV, although different instrumental teams do not agree on the detailed spectral shape. PAMELA also reported clearly the excessive feature of the fraction of positron above several GeV, but with no excess in antiprotons. Here we review the observational status and theoretical models of this interesting observational feature. We pay special attention to various physical interpretations proposed in the literature, including modified supernova remnant models for the e± background, new astrophysical sources, and new physics (the dark matter models). We suggest that although most models can make a case to interpret the data, with the current observational constraints the dark matter interpretations, especially those invoking annihilation, require much more exotic assumptions than some other astrophysical interpretations. Future observations may present some "smoking-gun" observational tests to differentiate different models and to identify the correct interpretation of the phenomenon.

Using FERMI TGF observation data to show an enhanced likelihood of TGF origin at the edges of stormcloud lightning clusters

2020 ◽  
Author(s):  
Paul Connell
Keyword(s):  
Outer Boundary ◽  
Cosmic Ray ◽  
High Energy ◽  
Observation Angle ◽  
Observation Data ◽  
Wind Drift ◽  
Cluster Radius ◽  
Electron Positron ◽  
Wide Range ◽  
Lightning Leader

<p>In designing the MXGS coded mask imager on the ASIM mission to the ISS many simulations of its performance were made using a model of TGF origin as a RREA in a vertical electric ffield at about 15 km altitude. One consequence was the prediction that imaging scatter background from high energy photons would be 15-20% of CZT detector counts, decreasing with TGF off-axis observation angle.</p><p>Analysis of the linear image reconstruction model shows the maximum scatter background to be 40% in some cases, with sources at the same off-axis angle having both small and large scatter background. The obvious reason to explain this asymmetry is that a TGF beam is not primarily vertical, but at large angles, and provokes an inference about TGF origin.</p><p>The phenomenon can be explained by TGF origin at the tips of lightning leader channels, resulting in a wide range of random beam angles, or in the macro electric ffield of the induced negative shfielding charge above a stormcloud. This charge might begin as concentrated near the top-centre of a stormcloud but should slowly spread out to form a torus-like charge with the greatest electric field on the circular boundary of the torus, over a range of angles from vertical to horizontal to downward - with many TGFs absorbed or expanding spherically as a low energy Compton Scatter Remant.</p><p>In this scenario the TGF would originate near the upper radial edge of the cloud, but not within it, either by lightning leader electron injection or electron positron injection from a cosmic ray shower, posing the question if this location of origin can be observed.</p><p>We made a study of over 6000 TGF locations from FERMI-WWLLN observations where the centroid centrepoint of the nearest lightning cluster to the TGF was located, allowing for wind drift, its RMSQ cluster radius determined, and its distance vector from the cluster centrepoint. If the cluster would represent stormcloud location and area, then the macro E-field scenario of TGF origin should result in an annular distribution of the TGF-WWLLN vector location, but convolved with the lightning location error distribution. We present the results here, showing there is indeed a significant increase in TGF origin at the outer boundary of stormcloud lightning clusters.</p>

SIMULATIONS OF RADIO EMISSION FROM COSMIC RAY AIR SHOWERS

2005 ◽  
Vol 20 (29) ◽  
pp. 6831-6833
Author(s):  
TIM HUEGE ◽  
HEINO FALCKE
Keyword(s):  
Radio Emission ◽  
Primary Particle ◽  
Cosmic Ray ◽  
Cost Effective ◽  
Azimuth Angle ◽  
Particle Energy ◽  
Particle Detector ◽  
Air Showers ◽  
Electron Positron ◽  
Air Fluorescence

Radio emission from cosmic ray air showers has the potential to become an additional, cost-effective observing technique for cosmic ray research, being largely complementary to the well-established particle detector and air fluorescence techniques. We present Monte Carlo simulations of radio emission from extensive air showers in the scheme of coherent geosynchrotron radiation from electron-positron pairs gyrating in the earth's magnetic field. Preliminary results of our simulations are the predicted frequency, primary particle energy, shower zenith angle, shower azimuth angle and polarization dependence of the radio emission. These properties can be directly related to data measured by LOPES and other experiments.

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