44Ti decay gamma-ray emission from young galactic supernova remnants

The discovery by COMPTEL of the 44Ti line emission at 1.16 MeV from the youngest known Galactic supernova remnant (SNR) Cas A has opened a new window for the investigation of SNR properties. This discovery also shows a way that could help to uncover missing young remnants of Galactic SNe that might have occurred some hundred years ago. Contrary to the situation at other wavelengths, in the γ-ray band the Galaxy is almost transparent, so that otherwise obscured supernova remnants may be detectable up to Av∼ 103 in γ-ray line emission. This is one of the direct ways to complement historical observations of Galactic SNe. Here we present preliminary results of the 6 year 44Ti line emission survey performed by COMPTEL on-board the Compton Gamma-Ray Observatory (CGRO)