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Titolo: Gamma-ray emission from novae related to positron annihilation: Constraints on its observability posed by new experimental nuclear data
Autore: Hernanz, M; Jose, J; Coc, A; Gomez-Gomar, J; Isern, J;
- Indirizzi:
- CSIC, Inst Estudis Espacials Catalunya, E-08034 Barcelona, Spain CSIC Barcelona Spain E-08034 pacials Catalunya, E-08034 Barcelona, Spain Dept Fis Enginyeria Nucl UPC, E-08800 Barcelona, Spain Dept Fis EnginyeriaNucl UPC Barcelona Spain E-08800 00 Barcelona, Spain Univ Paris 11, CNRS, Ctr Spectrometrie Nucl & Spectrometrie Masse, IN2P3, F-91405 Orsay, France Univ Paris 11 Orsay France F-91405 e Masse, IN2P3, F-91405 Orsay, France
- Titolo Testata:
- ASTROPHYSICAL JOURNAL
fascicolo: 2,
volume: 526,
anno: 1999,
parte:, 2
pagine: L97 - L100
- SICI:
- 0004-637X(199912)526:2<L97:GEFNRT>2.0.ZU;2-3
- Fonte:
- ISI
- Lingua:
- ENG
- Soggetto:
- CLASSICAL NOVAE; LINE EMISSION; HERCULIS 1991; SEARCH; AL-26; NA-22;
- Keywords:
- gamma rays : observations; novae, cataclysmic variables; nuclear reactions, nucleosynthesis, abundances;
- Tipo documento:
- Article
- Natura:
- Periodico
- Settore Disciplinare:
- Physical, Chemical & Earth Sciences
- Citazioni:
- 25
- Recensione:
- Indirizzi per estratti:
- Indirizzo: Hernanz, M CSIC, Inst Estudis Espacials Catalunya, Edifici Nexus 201,C Gran Capita 2-4, E-08034 Barcelona, Spain CSIC Edifici Nexus 201,C Gran Capita2-4 Barcelona Spain E-08034
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- Citazione:
- M. Hernanz et al., "Gamma-ray emission from novae related to positron annihilation: Constraints on its observability posed by new experimental nuclear data", ASTROPHYS J, 526(2), 1999, pp. L97-L100
Abstract
Classical novae emit gamma-ray radiation at 511 keV and below (with a cutoff at around 20-30 keV), related to positron annihilation and its Comptonization in the expanding envelope. This emission has been elusive up to now because it occurs at epochs well before the maximum in optical luminosity, but it could be detected by some sensitive instrument on board a satellite, provided that the nova is close enough and that it is observed at the rightmoment. The detection of this emission, which is a challenge for current and future gamma-ray instruments, would shed light into the physical processes that occur in the early phases of the explosion, which are invisible in other lower energy ranges. A good prediction of the emitted fluxes and of the corresponding detectability distances with different instruments relies critically on a good knowledge of reaction rates relevant to F-18 destruction, which have been subject to strong revision after recent nuclear spectroscopy measurements. With respect to previous results, smaller ejected masses of F-18 are predicted, leading to smaller emitted fluxes in the 20-511 keV range and shorter detectability distances.
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/06/13 alle ore 17:31:24