文章基本信息

标题：GeV Gamma-Rays from Supernova Remnants Interacting with Molecular Clouds
本地全文：下载
作者：Y. Uchiyama
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2010
卷号：2010
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We report the current status of the observations of supernova remnants (SNRs) with the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope, focusing on middle-aged SNRs that appear to be interacting with molecular clouds. Observations with the Fermi LAT in an energy range from 0.2 GeV to 100 GeV have unveiled the presence of luminous GeV gamma-ray emission in middle-aged SNRs, providing a new insight into the shock-acceleration theory and the origin of galactic cosmic rays. The middle-aged SNRs detected by the Fermi LAT are generally much brighter in GeV than in TeV in terms of energy flux, which empha- sizes the importance of the GeV observations. Spectral analysis of the bright objects revealed spectral steepening in the Fermi-LAT band. Remarkably, most (if not all) of them are known to be interacting with molecular clouds, and they are also the strong sources of synchrotron radio emission. We discuss possible scenarios to explain the enhanced GeV gamma-ray emission in the cloud-interacting SNRs. Particular emphasis is placed on a scenario in which shock-accelerated cosmic-rays are adiabatically compressed and energized as result of radiative cooling behind the cloud shock.