相关论文: On soil activation by cosmic rays at different alt…
In this study, we analysed active galactic nuclei in the "green valley" by comparing active and non-active galaxies using data from the COSMOS field. We found that most of our X-ray detected active galactic nuclei with far-infrared emission…
Active Galactic Nuclei are considered as possible sites of cosmic ray acceleration and some of them have been observed as high energy gamma ray emitters (Blazars). There naturally comes an appealing idea that the acceleration of the highest…
Active galactic nuclei (AGN) can produce both gamma rays and cosmic rays. The observed high-energy gamma-ray signals from distant blazars may be dominated by secondary gamma rays produced along the line of sight by the interactions of…
Cosmogenic neutrinos originate from interactions of cosmic rays propagating through the universe with cosmic background photons. Since both high-energy cosmic rays and cosmic background photons exist, the existence of high-energy cosmogenic…
The effects induced by muons with very low energies are usually neglected. In fact, they could represent a source of radioactive background due to capture processes in different materials, which in most of cases produce radioactive…
Ultra-high energy cosmic rays interacting with the radiation fields in the universe cause electromagnetic cascades resulting in a flux of extragalactic gamma rays, detectable to some 100 GeV. Recent precise measurements of the extragalactic…
We report on new simulations of the transport of energetic protons originating from the decay of energetic neutrons produced in solar flares. Because the neutrons are fast-moving but insensitive to the solar wind magnetic field, the decay…
We discuss the possibility of observing ultra high energy cosmic ray sources inhigh energy gamma rays. Protons propagating away from their accelerators produce secondary electrons during interactions with cosmic microwave background…
Four significant events of rapid $^{14}$C increase have taken place within the past several thousand years. The physical origin of these rapid increases is still a mystery but must be associated with extremely energetic cosmic processes.…
Cosmic ray interactions in the solar atmosphere yield a flux of electron and muon neutrinos with energies greater than 10 GeV. We discuss the influence of neutrino oscillations on the event rates in water-based Cerenkov detectors due to…
We consider the production of high energy neutrinos and cosmic rays in radio-quiet active galactic nuclei (AGN) or in the central regions of radio-loud AGN. We use a model in which acceleration of protons takes place at a shock in an…
Gamma rays from a solar flare in Active Region 10039 on 23 July 2002 with the RHESSI spacecraft spectrometer indicate that the CNO cycle occurs at the solar surface, in electrical discharges along closed magnetic loops. At the two feet of…
Gamma-Ray Bursts (GRBs) are expected to efficiently accelerate protons up to relativistic energies. High-energy photons can originate from decay of neutral pions produced by the interaction of these protons with the medium surrounding the…
Cosmic rays scattering with neutrinos produced in supernovae induce a flux of supernova neutrinos boosted to high energies. We calculate the neutrino flux arising from this new mechanism in environments with large cosmic-ray and supernova…
Gamma radiation associated with radon decay exhibits variations in both time of year and time of day. The annual oscillation has its maximum value in June, suggestive of a galactic influence. Measurements made at midnight show strong…
Cosmic rays may be linked to the formation of volatiles necessary for prebiotic chemistry. We explore the effect of cosmic rays in a hydrogen-dominated atmosphere, as a proof-of-concept that ion-neutral chemistry may be important for…
We show that the secondary electrons ejected from the ionization of heavy ions can be injected into the acceleration process that occurs at supernova remnant shocks. This electron injection mechanism works since ions are ionized during the…
High-energy cosmic rays, impinging on the atmosphere of the Earth initiate cascades of secondary particles, the extensive air showers. The electrons and positrons in the air shower emit electromagnetic radiation. This emission is detected…
In a previous work we investigated the propagation of fast moving charged particles in a spatially constant but slowly time dependent pseudoscalar background, such as the one provided by cold relic axions. The background induces cosmic rays…
As ultra-high energy cosmic ray protons propagate through the universe, they undergo photo-meson interactions with the cosmic microwave background, generating the `cosmogenic' neutrino flux. If a substantial fraction of the cosmic ray…