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

@article{Weidenspointner2008AnAD,
  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},
  journal={Nature},
  year={2008},
  volume={451},
  pages={159-162}
}
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
The 511 keV positron annhilation emission from the Galactic bulge has yet to solely be attributed to any astrophysical source of positrons. The 511 keV line, characteristic of electron-positron
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
The first $\ensuremath{\gamma}$-ray line originating from outside the Solar System that was ever detected is the 511 keV emission from positron annihilation in the Galaxy. Despite 30 years of intense
Galactic annihilation emission from nucleosynthesis positrons
Context. The Galaxy hosts a widespread population of low-energy positrons revealed by successive generations of gamma-ray telescopes through a bright annihilation emission from the bulge region, with
Gamma-ray spectroscopy of Positron Annihilation in the Milky Way
The annihilation of positrons in the Galaxy's interstellar medium produces characteristic gamma-rays with a line at 511 keV. This emission has been observed with the spectrometer SPI on INTEGRAL,
Positron annihilation spectrum from the Galactic Centre region observed by SPI/INTEGRAL revisited: annihilation in a cooling ISM?
We analyse SPI/INTEGRAL data on the 511-keV line from the Galactic Centre, accumulated over ∼6 yr of observations. We decompose the X-ray and soft gamma-ray emission of the central part of the Milky
Astrophysical signatures of leptonium
Abstract More than 1043 positrons annihilate every second in the centre of our Galaxy yet, despite four decades of observations, their origin is still unknown. Many candidates have been proposed,
THE GALACTIC POSITRON ANNIHILATION RADIATION AND THE PROPAGATION OF POSITRONS IN THE INTERSTELLAR MEDIUM
The ratio of the luminosity of diffuse 511 keV positron annihilation radiation, measured by INTEGRAL in its four years, from a Galactic "positron bulge" ( 3.5 kpc), the cascade of the magnetic
Positron astronomy with SPI/INTEGRAL
Abstract We provide an overview of positron astronomy results that have been obtained using the INTEGRAL spectrometer SPI, and discuss their implications for the still mysterious origin of positrons
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