Positron annihilation gamma rays from novae
نویسندگان
چکیده
منابع مشابه
Gamma-Rays from Positron Annihilation
SPI on INTEGRAL has provided spectra and a map of the sky in the emission from annihilations of positrons in the interstellar medium of our Galaxy. From high-resolution spectra we learned that a warm, partially-ionized medium is the site where the observed gamma-rays originate. The gamma-ray emission map shows a major puzzle for broader astrophysics topics, as it is dominated by a bright and ex...
متن کاملgamma rays from neutralino annihilation.
We calculate the ux of cosmic gamma rays expected from the annihilation of neutralinos in the Galactic halo. Our calculation of the annihilation cross section to two photons improves the existing calculations by inclusion of exact one-loop diagrams for the amplitudes involving Higgs boson and chargino states as well as those involving fermion and sfermion states. A survey of supersymmetric para...
متن کاملTgrs Observations of Gamma-ray Lines from Novae. I. Limits on the Positron Annihilation Line in Five Individual Novae
The Transient Gamma Ray Spectrometer (TGRS) on board the WIND spacecraft has spent most of the interval 1995–1997 in a high-altitude orbit where γ-ray backgrounds are low. Its high-resolution Ge spectrometer is thus able to detect weak lines which are slightly offset from stronger background features. One such line is predicted from nucleosynthesis in classical novae, where β-decays on a time-s...
متن کاملTgrs Observations of Positron Annihilation in Classical Novae
The TGRS experiment on board the Wind spacecraft has many advantages as a sky monitor — broad field of view (∼ 2π centered on the south ecliptic pole), long life (1994–present), and stable low background and continuous coverage due to Wind ’s high altitude high eccentricity orbit. The Ge detector has sufficient energy resolution (3–4 keV at 511 keV) to resolve a cosmic positron annihilation lin...
متن کاملGamma-Ray Emission from Novae Related to Positron Annihilation: Constraints on its Observability Posed by New Experimental Nuclear Data.
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 ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 1987
ISSN: 0004-637X,1538-4357
DOI: 10.1086/165816