Nuclear gamma-rays from energetic particle interactions

Ramaty, R.; Kozlovsky, B.; Lingenfelter, R. E.

doi:10.1086/190596

Cited by 281 publications

(205 citation statements)

References 62 publications

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“…Many narrow and broad lines are produced (e.g. Ramaty, Kozlovsky and Lingenfelter • 1979). The strongest narrow line is at 2.22 MeV from neutron capture on hydrogen.…”

Section: Gamma-raysmentioning

confidence: 99%

The Acceleration and Propagation of Solar Flare Energetic Particles

1985

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“…Many narrow and broad lines are produced (e.g. Ramaty, Kozlovsky and Lingenfelter • 1979). The strongest narrow line is at 2.22 MeV from neutron capture on hydrogen.…”

Section: Gamma-raysmentioning

confidence: 99%

The Acceleration and Propagation of Solar Flare Energetic Particles

1985

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“…So only a future gamma-ray mission with enhanced sensitivity in the MeV range will be able to obtain final results concerning the detection of de-excitation lines in Cas A. To compute the whole nuclear de-excitation spectrum for the specific case of Cas A, we used the Monte-Carlo code developed by Ramaty et al (1979) Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

“…The probability of observing gamma rays of energies between E γ and E γ + ΔE γ is then proportional to the sum of all angular distributions g for which E γ is in range. For a detailed description of the outlined methods above and a deeper insight into the different reaction types as well as the derivation of line production cross sections, we refer the reader to Ramaty et al (1979) and Kozlovsky et al (2002) and references therein.…”

Section: Theoretical Frameworkmentioning

confidence: 99%

Nuclear de-excitation line spectrum of Cassiopeia A

Elsässer

Mannheim

2011

A&A

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Context. The supernova remnant Cassiopeia A is a prime candidate for accelerating cosmic ray protons and ions. Gamma rays have been observed at GeV and TeV energies, which indicates hadronic interactions, but they could also be caused by inverse-Compton scattering of low-energy photons by accelerated electrons. Aims. We seek to predict the flux of nuclear de-excitation lines from Cas A through lower-energy cosmic rays and to compare it with COMPTEL measurements. Methods. Assuming a hadronic origin of the high-energy emission, we extrapolate the cosmic ray spectrum down to energies of 10 MeV, taking into account an equilibrium power-law momentum spectrum with a constant slope. We then calculate the nuclear line spectrum of Cassiopeia A, considering the most prominent chemical elements in the MeV band and their abundances as determined by X-ray spectroscopy. Results. We show that the predicted line spectrum is close to the level of the COMPTEL sensitivity and agrees with conservative upper limits.

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“…(2) high-energy collisions in objects or interstellar space, which lead to excitations of nuclear levels, followed by de-excitation with accompanied characteristic gamma-ray line emission [105,65]. Such high-energy interactions also produce continuum gamma-rays through the processes of inverse-Compton scattering, Bremsstrahlung, and other radiation processes related to acceleration of charges in strong fields such as curvature radiation and synchrotron emission.…”

Section: Cosmic Gamma-rays and Their Spectramentioning

confidence: 99%

“…Cosmic-ray interactions with interstellar gas are expected to produce spectral signatures at gamma-ray energies through excitation of nuclear levels, and through pion decay and higher-energy nucleonic excitations [105]. We concentrate on signatures from atomic nuclei here, leaving pion and GeV lines aside (see [122] for a review of continuum processes).…”

Section: Low-energy Cosmic Ray Interactionsmentioning

confidence: 99%

Cosmic Gamma-Ray Spectroscopy

Diehl

2013

Astronomical Review

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Penetrating gamma-rays require complex instrumentation for astronomical spectroscopy measurements of gamma-rays from cosmic sources. Multiple-interaction detectors in space combined with sophisticated postprocessing of detector events on ground have lead to a spectroscopy performance which is now capable to provide new astrophysical insights. Spectral signatures in the MeV regime originate from transitions in the nuclei of atoms (rather than in their electron shell). Nuclear transitions are stimulated by either radioactive decays or high-energy nuclear collisions such as with cosmic rays. Gamma-ray lines have been detected from radioactive isotopes produced in nuclear burning inside stars and supernovae, and from energetic-particle interactions in solar flares. Radioactive-decay gamma-rays from 56 Ni directly reflect the source of supernova light. 44 Ti is produced in core-collapse supernova interiors, and the paucity of corresponding 44 Ti gamma-ray line sources reflects the variety of dynamical conditions herein. 26 Al and 60 Fe are dispersed in interstellar space from massive-star nucleosynthesis over millions of years. Gamma-rays from their decay are measured in detail by gamma-ray telescopes, astrophysical interpretations reach from massive-star interiors to dynamical processes in the interstellar medium. Nuclear de-excitation gamma-ray lines have been found in solar-flare events, and convey information about energetic-particle production in these events, and their interaction in the solar atmosphere. The annihilation of positrons leads to another type of cosmic gamma-ray source. The characteristic annihilation gamma-rays at 511 keV have been measured long ago in solar flares, and now throughout the interstellar medium of our Milky Way galaxy. But now a puzzle has appeared, as a surprising predominance of the central bulge region was determined. This requires either new positron sources or transport processes not yet known to us. In this paper we discuss instrumentation and data processing for cosmic gamma-ray spectroscopy, and the astrophysical issues and insights from these measurements.

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Nuclear gamma-rays from energetic particle interactions

Cited by 281 publications

References 62 publications

The Acceleration and Propagation of Solar Flare Energetic Particles

The Acceleration and Propagation of Solar Flare Energetic Particles

Nuclear de-excitation line spectrum of Cassiopeia A

Cosmic Gamma-Ray Spectroscopy

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