HEAO 3 discovery of Al-26 in the interstellar medium

Mahoney, W. A.; Ling, J. C.; Wheaton, W. A.; Jacobson, Allan

doi:10.1086/162632

Cited by 260 publications

(130 citation statements)

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“…However, the expected line centroid, without any redshift, is at 0.45 MeV and this is in marginal conflict with the Nova Muscae observation, for which the line centroid was at 0.48 ± 0.02 MeV (Goldwurm et al 1992), and definitely with the 1977 observation for which the line centroid was at 0.496 MeV. On the other hand, the observations (Martin et al 1992; of high lithium abundances in the binary companions of the black hole candidates V404 Cygni, Cen X-4 and A0620, possibly due to α-α reactions in the accretion disks of the holes, do provide support for this model. Again Compton backscattering of these α-α photons from the inner region of an optically thick accretion disk could account for the < ∼ 0.2 MeV line emission.…”

Section: Line Features From Black Hole Candidatescontrasting

confidence: 58%

“…The 1.809 MeV line was first detected (Mahoney et al 1984) from the direction of the Galactic center with the HEAO-3 high resolution Ge spectrometer and was subsequently confirmed by observations (Share et al 1985) with the NaI detector on SMM, and balloon borne Ge instruments (e.g. MacCallum et al 1987).…”

Section: Gamma Ray Line Emission From 26 Al Decaymentioning

confidence: 78%

“…Estimates (Mahoney et al 1984;Skibo, Ramaty and Leventhal 1992) of the total amount of 26 Al that resides in the Galaxy range from about 1.7 to 3M ⊙ , depending on assumed model for the Galactic distribution of 26 Al, the distance to the Galactic center and the exact values of the 1.809 MeV line fluxes implied by the observations. It should be emphasized that the derivation of a photon flux from data obtained by wide field of view detectors such as SMM and HEAO-3 does depend on the assumed longitude and latitude distribution of the 1.809 MeV line emission.…”

Section: Gamma Ray Line Emission From 26 Al Decaymentioning

confidence: 99%

“…Excited nuclear levels can be populated by the decay of long-lived radioactive nuclei as well as directly in interactions of accelerated particles with ambient gas. Nuclear deexcitation lines following radioactive decay have been seen from supernova 1987A (Matz et al 1988;Tueller et al 1990;Kurfess et al 1992), from the supernova remnants Cas A (Iyudin et al 1994) and Vela (Diehl et al 1995), and the interstellar medium (Mahoney et al 1984;Share et al 1985;Diehl et al 1994;. The observation of such line emission provides unique information on processes of nucleosynthesis.…”

Section: Introductionmentioning

confidence: 99%

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Astrophysical Gamma Ray Emission Lines

Ramaty¹,

Lingenfelter²

1995

The Analysis of Emission Lines

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We review the wide range of astrophysical observations of gamma ray emission lines and we discuss their implications. We consider line emission from solar flares, the Orion molecular cloud complex, supernovae 1987A and 1991T, the supernova remnants Cas A and Vela, the interstellar medium, the Galactic center region and several Galactic black hole candidates. The observations have important, and often unique, implications on particle acceleration, star formation, processes of nucleosynthesis, Galactic evolution and compact object physics.

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Section: Line Features From Black Hole Candidatescontrasting

confidence: 58%

Section: Gamma Ray Line Emission From 26 Al Decaymentioning

confidence: 78%

Section: Gamma Ray Line Emission From 26 Al Decaymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Astrophysical Gamma Ray Emission Lines

Ramaty¹,

Lingenfelter²

1995

The Analysis of Emission Lines

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“…The 26 Al line from the interstellar medium in the Galaxy was the first nuclear line detected from outside the solar system [83]. It had been attributed to current nucleosynthesis in our Galaxy, although the source remained unclear for a while between novae, Wolf-Rayet stars, supernovae, and even solar system origins.…”

Section: Al In the Galaxymentioning

confidence: 81%

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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The history of gamma-ray astronomy

Schönfelder

2002

Astron. Nachr.

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HEAO 3 discovery of Al-26 in the interstellar medium

Cited by 260 publications

References 0 publications

Astrophysical Gamma Ray Emission Lines

Astrophysical Gamma Ray Emission Lines

Cosmic Gamma-Ray Spectroscopy

The history of gamma-ray astronomy

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