Related papers: Gamma-Rays from Positron Annihilation
With the launch of ESA's INTEGRAL satellite in october 2002, a gamma-ray observatory will become available to the scientific community that combines imaging and spectroscopic capacities in the 20 keV to 10 MeV energy range. In this paper,…
Observations of the gamma-ray sky reveal the most powerful sources and the most violent events in the Universe. While at lower wavebands the observed emission is generally dominated by thermal processes, the gamma-ray sky provides us with a…
We have processed the data accumulated with INTEGRAL SPI during 4 years (~ 51 Ms) to study the Galactic ``diffuse'' emission morphology in the 20 keV to 8 MeV energy range. To achieve this objective, we have derived simultaneously an…
Measurements of high-energy photons from cosmic sources of nuclear radiation through ESA's INTEGRAL mission have advanced our knowledge: New data with high spectral resolution showed that characteristic gamma-ray lines from radioactive…
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 a fainter contribution from the inner disk. The…
Gamma-ray lines from cosmic sources provide unique isotopic information, since they originate from energy level transitions in the atomic nucleus. Gamma-ray telescopes explored this astronomical window in the past three decades, detecting…
Studies based on the gamma-ray lines from radioactive decay of unstable isotopes produced in massive-star and supernova nucleosynthesis have been among INTEGRAL's prominent science achievements. 26Al has become a tool to study specific…
Although the annihilation of positrons towards the Galactic centre was established more than 50 years ago through the detection of a 511 keV $\gamma$-ray line, the origin of the positrons remains unknown. The $\gamma$-ray line should be…
With the INTEGRAL observatory, ESA has provided a unique tool to the astronomical community revealing hundreds of sources, new classes of objects, extraordinary views of antimatter annihilation in our Galaxy, and fingerprints of recent…
The status of the analysis of the electron/positron annihilation radiation performed by INTEGRAL/SPI in the 4th GALACTIC QUADRANT is reported. We use data from the first two Galactic Center Deep Exposures (GCDE) and from the Galactic Plane…
Electron-positron annihilation radiation from the Galactic Center region has been detected since the seventies, but its astrophysical origin is still a topic of a scientific debate. We have analyzed data of the gamma-ray imager IBIS/ISGRI…
With the unequalled INTEGRAL observatory, ESA has provided a unique tool to the astronomical community that has made Europe the world leader in the field of gamma-ray astronomy. INTEGRAL provides an unprecedented survey of the soft…
The spectrometer SPI on INTEGRAL allows for the first time simultaneous imaging of diffuse and point-like emission in the hard X-ray and soft gamma-ray regime. To fully exploit the capabilities of the instrument, we implemented the MREM…
The SPI spectrometer aboard of the INTEGRAL satellite has released a map of the e+e- annihilation emission line of unprecedented quality, showing that most of the photons arise from a region coinciding with the stellar bulge of the Milky…
We report the first measurements of the 511 keV line emission from the Galactic Centre (GC) region performed with the spectrometer SPI on the space observatory INTEGRAL (International Gamma-Ray Astrophysics Laboratory). Taking into account…
The annihilation of light dark matter was recently advocated as a possible explanation of the large positron injection rate at the Galactic center deduced from observations by the SPI spectrometer aboard INTEGRAL. The modelling of internal…
Observations of annihilation radiation in the Galaxy are briefly reviewed. We summarize astrophysical mechanisms leading to positron production, and recent estimates for production rates from nova and supernova nucleosynthesis in the…
Observations of soft gamma rays emanating from the Milky Way from SPI/\textit{INTEGRAL} reveal the annihilation of $\sim2\times10^{43}$ positrons every second in the Galactic bulge. The origin of these positrons, which annihilate to produce…
We consider positron propagation in the interstellar medium and show that the positrons from the beta-plus decay chains of the radioactive nuclei Ni-56, Ti-44, and Al-26, produced in Galactic supernovae, can fully account for all the…
The observation of a strong and extended positron-electron line annihilation emission in the central regions of the Galaxy by INTEGRAL-SPI, consistent with the Galactic bulge geometry, without any counterpart in the gamma-ray range, neither…