منابع مشابه
Annihilation Fountain in the Galactic Center Region
Two different model-independent mapping techniques have been applied to CGRO OSSE, SMM, TGRS and balloon data and reveal a feature in the 0.511 MeV e +-e − annihilation radiation pattern of our galaxy centered at ℓ ∼ −2 • and b ∼ 10 • with a flux of ∼ 5 · 10 −4 0.511 MeV ph cm −2 s −1. If near the galactic center, then e + sources are producing ∼ 10 42 e + s −1 which annihilate ≈ 1-2 kpc above ...
متن کاملAn annihilation fountain at the Galactic center?
Recently, data of taken with the OSSE experiment have been combined with scanning observations by TGRS and SMM to produce maps of the narrow Galactic 511 keV line emission (Purcell et al. 1997). A modelling of the combined data give evidence for three distinct features: the Galactic plane, a central bulge, and an extended emission region at positive latitudes above the Galactic center. It has b...
متن کاملThree-Dimensional Evolution of the Galactic Fountain
Gas that escapes from the Galactic disk, rises into the halo, cools and falls back, constitutes a “Galactic fountain”. Three-dimensional simulations show that such a fountain model reproduces many of the features that have been observed in the Galaxy and other galaxies such as M31 and M33. Here, these results are reported.
متن کاملEvidence for GeV emission from the Galactic Center Fountain
The region near the Galactic center may have experienced recurrent episodes of injection of energy in excess of ∼ 10 ergs due to repeated starbursts involving more than ∼ 10 supernovae. This hypothesis can be tested by measurements of γ-ray lines produced by the decay of radioactive isotopes and positron annihilation, or by searches for pulsars produced during starbursts. Recent OSSE observatio...
متن کاملGalactic dynamo and helicity losses through fountain flow
Aims. Nonlinear behaviour of galactic dynamos is studied, allowing for magnetic helicity removal by the galactic fountain flow. Methods. A suitable advection speed is estimated, and a one-dimensional mean-field dynamo model with dynamic α-effect is explored. Results. It is shown that the galactic fountain flow is efficient in removing magnetic helicity from galactic discs. This alleviates the c...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1997
ISSN: 0252-9211
DOI: 10.1017/s0252921100071487