Some Astrophysical Implications of Recent Measurements on the Intensity of Cosmic-Ray Electrons

1968 ◽  
Vol 1 (3) ◽  
pp. 112-113 ◽  
Author(s):  
W.R. Webber
Keyword(s):  
Electron Spectrum ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
List Type ◽  
Secondary Electrons ◽  
The Earth ◽  
Thermal Radio Emission ◽  
The Galaxy ◽  
Electron Intensity ◽  
Spiral Arm

We have extended our recent measurements on the extraterrestrial cosmic ray electron spectrum, this spectrum now being determined over the energy range from ~15 MeV to 6 GeV. The extraterrestrial electron intensity between 15 MeV and 200 MeV can be determined unambiguously by studying the diurnal variation of these particles. We have also measured the effects of the 11-year solar modulation on the electrons, thus enabling the electron spectrum observed near the Earth to be extrapolated to the local region of the spiral arm. It is the purpose of this paper to relate these measurements to: (i) calculations of ‘secondary’ electrons produced by cosmic ray nuclei moving in the Galaxy; and(ii) the observations of non-thermal radio emission from disk components of the Galaxy.

The non-thermal radio-emission from the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 337-354 ◽  
Author(s):  
J. E. Baldwin
Keyword(s):  
Supernova Remnants ◽  
Large Scale ◽  
Cosmic Ray ◽  
Radio Spectrum ◽  
List Type ◽  
Continuum Radiation ◽  
Radio Halo ◽  
Normal Galaxies ◽  
Thermal Radio Emission ◽  
The Galaxy

In this review of the non-thermal continuum radiation from the Galaxy, the following issues are discussed:(1)The non-thermal continuum radiation in the disk.(2)Evidence for spiral arms in the non-thermal continuum, and the origin of the radiation in sources or in large-scale magnetic fields.(3)The nature of the spurs extending to high galactic latitudes.(4)Evidence for the existence or absence of a radio halo.(5)The galactic radio spectrum and its relation to the cosmic-ray electron spectrum.(6)Supernova remnants, their structure and spectra.(7)A comparison of the Galaxy with other normal galaxies.(8)Observational needs.

scholarly journals On the Relationship Between Recent Measurements of Cosmic Ray Electrons, Nonthermal Radio Emission from the Galaxy, and the Solar Modulation of Cosmic Rays

1968 ◽  
Vol 21 (6) ◽  
pp. 845 ◽  
Author(s):  
WR Webber
Keyword(s):  
Cosmic Rays ◽  
Radio Emission ◽  
Electron Spectrum ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Nonthermal Radio ◽  
The Galaxy ◽  
Nonthermal Radio Emission ◽  
Modulation Parameter ◽  
The Relationship

Utilizing recent measurements of the cosmic ray electron spectrum at the Earth and the effects of solar modulation on this spectrum, possible limits on the local interstellar electron spectrum have been determined. Synchrotron emission from these interstellar electrons is then compared with the local (disk) volume emissivity of nonthermal radio emission as deduced from a study of radio intensity profiles along the galactic equator. The detailed spectrum and magnitude of radio emissivity can be reproduced from the electron spectrum only for very stringent, conditions on the magnitude of the local interstellar magnetic field, and the amount of solar modulation of cosmic rays. Specifically it is found that B -L "'" 7 !-,G, and the residual modulation parameter KR "'" 0�75 GV. If solar modulation effects on the cosmic ray electron component are negligible then an implausibly high local field of "'" 20 !-,G is required.

Influence of supernovae, gamma-ray bursts, solar flares, and cosmic rays on the terrestrial environment

2008 ◽  
Author(s):  
Arnon Dar
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Gamma Ray Bursts ◽  
The Sun ◽  
Terrestrial Environment ◽  
The Earth ◽  
The Galaxy ◽  
Threat To Life

Changes in the solar neighbourhood due to the motion of the sun in the Galaxy, solar evolution, and Galactic stellar evolution influence the terrestrial environment and expose life on the Earth to cosmic hazards. Such cosmic hazards include impact of near-Earth objects (NEOs), global climatic changes due to variations in solar activity and exposure of the Earth to very large fluxes of radiations and cosmic rays from Galactic supernova (SN) explosions and gamma-ray bursts (GRBs). Such cosmic hazards are of low probability, but their influence on the terrestrial environment and their catastrophic consequences, as evident from geological records, justify their detailed study, and the development of rational strategies, which may minimize their threat to life and to the survival of the human race on this planet. In this chapter I shall concentrate on threats to life from increased levels of radiation and cosmic ray (CR) flux that reach the atmosphere as a result of (1) changes in solar luminosity, (2) changes in the solar environment owing to the motion of the sun around the Galactic centre and in particular, owing to its passage through the spiral arms of the Galaxy, (3) the oscillatory displacement of the solar system perpendicular to the Galactic plane, (4) solar activity, (5) Galactic SN explosions, (6) GRBs, and (7) cosmic ray bursts (CRBs). The credibility of various cosmic threats will be tested by examining whether such events could have caused some of the major mass extinctions that took place on planet Earth and were documented relatively well in the geological records of the past 500 million years (Myr). A credible claim of a global threat to life from a change in global irradiation must first demonstrate that the anticipated change is larger than the periodical changes in irradiation caused by the motions of the Earth, to which terrestrial life has adjusted itself. Most of the energy of the sun is radiated in the visible range. The atmosphere is highly transparent to this visible light but is very opaque to almost all other bands of the electromagnetic spectrum except radio waves, whose production by the sun is rather small.

scholarly journals Time dependence of the helium flux measured by PAMELA

2019 ◽  
Vol 209 ◽  
pp. 01004
Author(s):  
N. Marcelli ◽  
O. Adriani ◽  
G. C. Barbarino ◽  
G. A. Bazilevskaya ◽  
R. Bellotti ◽  
...  
Keyword(s):  
Energy Range ◽  
Time Dependence ◽  
Cosmic Radiation ◽  
Cosmic Ray ◽  
Space Experiment ◽  
Precision Measurements ◽  
Solar Modulation ◽  
Monthly Basis ◽  
The Galaxy ◽  
Crucial Information

Precision measurements of the Z = 2 component in cosmic radiation provide crucial information about the origin and propagation of the second most abundant cosmic ray species in the Galaxy (9% of the total). These measurements, acquired with the PAMELA space experiment orbiting Earth, allow to study solar modulation in details. Helium modulation is compared to the modulation of protons to study possible dependencies on charge and mass. The time dependence of helium fluxes on a monthly basis measured by PAMELA has been studied for the period between July 2006 to January 2016 in the energy range from 800 MeV/n to ~ 20 GeV/n.

scholarly journals Solar Modulation Effects in Terrestrial Production of Carbon-14

Radiocarbon ◽  
1980 ◽  
Vol 22 (2) ◽  
pp. 133-158 ◽  
Author(s):  
Giuliana Castagnoli ◽  
Devendra Lal
Keyword(s):  
Solar Activity ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Carbon 14 ◽  
Cosmic Ray Modulation ◽  
The Earth ◽  
Secular Variations ◽  
Galactic Cosmic Ray ◽  
Long Term Variations

This paper is concerned with the expected deviations in the production rate of natural 14C on the earth due to changes in solar activity. We review the published estimates of the global production rates of 14C due to galactic and solar cosmic ray particles, and present new estimates of the expected secular variations in 14C production, taking into account the latest information available on galactic cosmic ray modulation and long-term variations in solar activity.

scholarly journals Galactic Anisotropy of Cosmic Ray Intensity Observed by an Air Shower Experiment

2006 ◽  
Vol 23 (3) ◽  
pp. 129-134
Author(s):  
Mahmud Bahmanabadi ◽  
Mehdi Khakian Ghomi ◽  
Farzaneh Sheidaei ◽  
Jalal Samimi
Keyword(s):  
Daily Variation ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Extensive Air Shower ◽  
Air Shower ◽  
The Earth ◽  
The Galaxy ◽  
Unidirectional Anisotropy ◽  
Galactic Cosmic Ray ◽  
Shower Array

AbstractWe have monitored multi-TeV cosmic rays by a small air shower array in Tehran (35°43′ N, 51°20′ E, 1200 m = 890 g cm−2). More than 1.1 × 106 extensive air shower events were recorded. These observations enabled us to analyse sidereal variation of the galactic cosmic ray intensity. The observed sidereal daily variation is compared to the expected variation which includes the Compton–Getting effect due to the motion of the earth in the Galaxy. In addition to the Compton–Getting effect, an anisotropy has been observed which is due to a unidirectional anisotropy of cosmic ray flow along the Galactic arms.

scholarly journals Neutrino flux from cosmic ray accelerators in the Cygnus spiral arm of the Galaxy

2007 ◽  
Vol 76 (6) ◽  
Author(s):  
Luis Anchordoqui ◽  
Francis Halzen ◽  
Teresa Montaruli ◽  
Aongus Ó Murchadha
Keyword(s):  
Neutrino Flux ◽  
Cosmic Ray ◽  
The Galaxy ◽  
Spiral Arm

Interplanetary and solar electrons of energy 3–12 MeV

1968 ◽  
Vol 46 (10) ◽  
pp. S761-S765 ◽  
Author(s):  
T. L. Cline ◽  
F. B. McDonald
Keyword(s):  
Interplanetary Space ◽  
Solar Physics ◽  
Strong Dependence ◽  
Cosmic Ray ◽  
High Energy ◽  
Solar Modulation ◽  
Relativistic Electrons ◽  
Time Histories ◽  
Electron Intensity ◽  
Time Variations

This paper reviews two topics related to the low-energy relativistic electrons detected in interplanetary space with the satellites IMP-I, IMP-II, and IMP-III:1. The first observations of 3–12-MeV solar-flare electrons in interplanetary space are presented. The solar electrons detected have kinetic energies nearly two orders of magnitude higher than any previously studied; thus, although flare events with a detectable flux of such particles occur relatively rarely, their study provides a new parameter in solar physics. The 7 July and 14 September 1966 events are outlined in detail, having the greatest relativistic electron to medium-energy proton ratios of the events detected before 1967. These events contrast with the 28 August 1966 event, which was intense in nucleons but contained no detectable component of relativistic electrons. The electron time histories are shown to have delayed onsets, and to be similar in form to those of high-energy protons, and the energy spectra and other features are described.2. Progress in the study of the solar modulation of interplanetary 3–12-MeV electrons is reviewed. Characteristics of the electron-intensity time variations during parts of 1963–67 are outlined; they are shown to be consistent with the hypothesis of the primary cosmic-ray nature of these particles and with a strong dependence on the local field conditions.

scholarly journals Publisher’s Note: Neutrino flux from cosmic ray accelerators in the Cygnus spiral arm of the Galaxy [Phys. Rev. D76, 067301 (2007)]

2008 ◽  
Vol 77 (6) ◽  
Author(s):  
Luis Anchordoqui ◽  
Francis Halzen ◽  
Teresa Montaruli ◽  
Aongus Ó Murchadha
Keyword(s):  
Neutrino Flux ◽  
Cosmic Ray ◽  
The Galaxy ◽  
Spiral Arm
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