Vortragsdetails

Mittwoch, 19. Januar 2011 - 15:15

Sabrina Casanova (MPIK/Bochum):

"Molecular Clouds as Cosmic Ray Laboratories"

Zusammenfassung. Cosmic rays up to at least 10^{15} eV are believed to be emitted by Galactic sources, such as supernova remnants. However, no conclusive evidence of their acceleration has been found yet. A trace of ongoing cosmic ray acceleration is the gamma-ray emission produced by these highly energetic particles when they scatter off the interstellar medium gas, mainly atomic, molecular and ionised hydrogen. In fact, from the hadronic collisions neutral pions emerge and in turn they decay into two gammas. For this reason gamma-ray astronomy has always played a key role to probe the Galactic cosmic ray flux and to solve the long standing question of the origin of cosmic rays. Whereas the atomic hydrogen is uniformly distributed in the Galaxy, the molecular hydrogen is usually aggregated in dense clouds, and the gamma-ray emission from such clouds is particularly intense. A multi-frequency approach, which combines the data from the present and future gamma-ray missions with the data from the submillimeter and milli-meter surveys of the molecular hydrogen, is therefore crucial to probe the Galactic cosmic ray flux. We will here discuss in particular the emission from molecular clouds in the vicinity of the young SNR RX~J1713-3946 and in molecular clouds illuminated by the background CR flux.