Early SPI/INTEGRAL measurements of 511 keV line emission from the 4th quadrant of the Galaxy
Early SPI/INTEGRAL measurements of 511 keV line emission from the 4th quadrant of the Galaxy
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 range of spatial distribution models which are consistent with the data, we derive a flux …