An asymmetric distribution of positrons in the Galactic disk revealed by γ-rays

  title={An asymmetric distribution of positrons in the Galactic disk revealed by $\gamma$-rays},
  author={Georg Weidenspointner and Gerald K. Skinner and P. Jean and J{\"u}rgen Kn{\"o}dlseder and Peter von Ballmoos and Giovanni Fabrizio Bignami and Roland Diehl and A. W. Strong and Bertrand Cordier and Stéphane Schanne and C. Winkler},
Gamma-ray line radiation at 511 keV is the signature of electron–positron annihilation. Such radiation has been known for 30 years to come from the general direction of the Galactic Centre, but the origin of the positrons has remained a mystery. Stellar nucleosynthesis, accreting compact objects, and even the annihilation of exotic dark-matter particles have all been suggested. Here we report a distinct asymmetry in the 511-keV line emission coming from the inner Galactic disk (∼10–50° from the… 
On the origin of the 511-keV emission in the Galactic Centre
Diffuse 511 keV line emission, from the annihilation of cold positrons, has been observed in the direction of the Galactic Centre for more than 30 years. The latest high-resolution maps of this
The Origin of the 511 keV Positron Annihilation Emission Morphology
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Positron Transport and Annihilation in the Galactic Bulge
The annihilation of positrons in the Milky Way Galaxy has been observed for ∼50 years; however, the production sites of these positrons remains hard to identify. The observed morphology of positron
The 511 keV emission from positron annihilation in the Galaxy
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Gamma-ray spectroscopy of Positron Annihilation in the Milky Way
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Positron annihilation spectrum from the Galactic Centre region observed by SPI/INTEGRAL revisited: annihilation in a cooling ISM?
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Astrophysical signatures of leptonium
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The all-sky distribution of 511 keV electron-positron annihilation emission
We present a map of 511 keV electron-positron annihilation emission, based on data accumulated with the SPI spectrometer aboard ESA's INTEGRAL gamma-ray observatory, that covers approximately 95% of
Annihilation Emission from the Galactic Black Hole
Both diffuse high-energy gamma rays and an extended electron-positron annihilation line emission have been observed in the Galactic Center (GC) region. Although X-ray observations indicate that the
The sky distribution of positronium annihilation continuum emission measured with SPI/INTEGRAL
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Positron annihilation radiation from the inner galaxy
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Positronium origin of 476 keV galactic feature.
LEVENTHAL1 has noticed that the γ-ray spectrum due to the annihilation of positronium, which consists of two 511 keV photons from the singlet state and three photons from the triplet state, produces
The sky distribution of 511 KeV positron annihilation line emission as measured with INTEGRAL/SPI
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Detection of 511 keV positron annihilation radiation from the galactic center direction. [gamma ray astronomy
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GRIS observations of positron annihilation radiation from the Galactic center
In the present Gamma-Ray Imaging Spectrometer (GRIS) observations, the 511 keV line has been spectrally resolved and the Galactic plane and center components have been independently measured. These