Speaker
Roland Diehl
(MPE Garching)
Description
Gamma-ray spectrometers with high spectral resolution are operating in space since
2002: RHESSI and SPI on INTEGRAL. Understanding the instrumental response and
backgrounds is major effort but a prerequisite of detailed science interpretations.
While 44Ti from core collapse supernovae could not be detected, this still adds
constraints to Cas A 44Ti ejection. Diffuse nucleosynthesis is studied through 26Al,
60Fe, and positron annihilation gamma-ray measurements. With SPI on INTEGRAL, the
gamma-ray line from decay of radioactive 26Al could be measured at unpredecented
spectroscopic precision. This made possible a new determination of the total mass of
26Al produced by stellar sources throughout the Galaxy, and an analysis of the
properties of the interstellar medium around 26Al sources. 60Fe is clearly detected
with SPI, its intensity ratio to 26Al is confirmed to be on the lower side of
theoretical predictions. Nucleosynthesis sources are probably minor contributors to
Galactic positrons, as deduced from the bulge-centered spatial distribution of the
annihilation gamma-ray emission.
Primary author
Roland Diehl
(MPE Garching)
