Galactic 26Al:: probe of supernovae and pulsars

Al-26 is an unstable isotope with the mean lifetime of 1 Myr. It is mainly synthesized in massive stars, before and during their evolution to core-collapse supernovae. Since the gamma-ray line is transparent to the interstellar medium, studies of Al-26 could probe the nucleosynthesis activity and supernova explosions in the whole Galaxy in last few million ears. INTEGRAL/SPI has a high spectral resolution to study the 1809 keV gamma-my line from Al-26. We have detected Al-26 from the Galactic plane and nearby star-formation regions. From Al-26 measurements, we obtain the current Galactic core-collapse supernova rate of 1.9 events per century. Correlation between the distribution of Al-26 candidate sources and the distributions of detected SNRs and pulsars in the Galaxy is discussed.