摘要
The standard model of cosmic ray propagation has been very successful in explaining all kinds of galactic cosmic ray spectra. However, high precision measurement have recently revealed an appreciable discrepancy between data and model expectations, from spectrum observations of γ-rays, e＋/e- and probably the B/C ratio starting from -10 GeV energy. In this work, we propose that a hard galactic plane component, supplied by the fresh cosmic ray sources and detained by local magnetic fields, can contribute additional secondary particles interacting with local materials. By properly choosing the intensity and spectral index of the harder component up to multi-TeV energy, a two-component T-ray spectrum is obtained and agrees very well with the observation. Simultaneously, the expected neutrino numbers from the galactic plane could contribute - 60% of IceCube observed neutrino number below a few hundreds of TeV under our model. In addition to these studies, we find that the same pp-collision process responsible for the excess gamma ray emission could account for a significant amount of the positron excess, but a more detailed mechanism is needed for a full agreement. It is expected that the excesses in the p/p and B/C ratio will show up when energy is above ,-10 GeV. We look forward this model being tested in the near future by new observations from AMS02, IceCube, AS% HAWC and future experiments such as LHASSO, HiSCORE and CTA.
The standard model of cosmic ray propagation has been very successful in explaining all kinds of galactic cosmic ray spectra. However, high precision measurement have recently revealed an appreciable discrepancy between data and model expectations, from spectrum observations of γ-rays, e＋/e- and probably the B/C ratio starting from -10 GeV energy. In this work, we propose that a hard galactic plane component, supplied by the fresh cosmic ray sources and detained by local magnetic fields, can contribute additional secondary particles interacting with local materials. By properly choosing the intensity and spectral index of the harder component up to multi-TeV energy, a two-component T-ray spectrum is obtained and agrees very well with the observation. Simultaneously, the expected neutrino numbers from the galactic plane could contribute - 60% of IceCube observed neutrino number below a few hundreds of TeV under our model. In addition to these studies, we find that the same pp-collision process responsible for the excess gamma ray emission could account for a significant amount of the positron excess, but a more detailed mechanism is needed for a full agreement. It is expected that the excesses in the p/p and B/C ratio will show up when energy is above ,-10 GeV. We look forward this model being tested in the near future by new observations from AMS02, IceCube, AS% HAWC and future experiments such as LHASSO, HiSCORE and CTA.
基金
Supported by the Ministry of Science and Technology of China,Natural Sciences Foundation of China(11135010)
