Related papers: Neutrino Conversions in Active Galactic Nuclei
I discuss the possibility of production of high energy cosmic tau neutrinos ($E \geq 10^{6}$ GeV) in an astrophysical site and study some of the effects of neutrino mixing on their subsequent propagation. I also discuss the prospects for…
Production of the expected high energy neutrino flux with energy greater than tens of thousands of GeV in some astrophysical sites such as the galactic plane as well as the centers of some distant galaxies is reviewed. The expected changes…
Several cosmologically distant astrophysical sources may produce ultra-high energy cosmic neutrinos (E > 10^6 GeV) of all flavors above the atmospheric neutrino background. I study the effects of vacuum neutrino flavor mixing on this cosmic…
Active Galactic Nuclei (AGN) are sources of high-energy gamma-rays and are considered to be promising candidates to be sources of high-energy cosmic rays and neutrinos as well. We present and discuss various models for ion acceleration and…
We study prospects for the observations of high-energy cosmic tau neutrinos (E \geq 10^6 GeV) originating from proton acceleration in the cores of active galactic nuclei. We consider the possibility that vacuum flavor neutrino oscillations…
Active galactic nuclei (AGN) are believed to be promising candidates of extragalactic cosmic-ray accelerators and sources, and associated high-energy neutrino and hadronic gamma-ray emission has been studied for many years. We review models…
I give a brief critical review of the predicted intensity of diffuse high energy neutrinos of astrophysical origin over the energy range from 10^12 eV to 10^24 eV. Neutrinos from interactions of galactic cosmic rays with interstellar matter…
Active Galactic Nuclei are considered as sources of neutrinos, with neutrino energies extending up to 10^{18} eV. It is expected that these highly energetic cosmic neutrinos will be detected by the neutrino telescopes, presently under…
Astronomy at the highest energies observed must be performed by studying neutrinos rather than photons because the universe is opaque to photons of these energies. By making observations of neutrinos with energies above 10 EeV one can…
I give a brief discussion of possible sources of high energy neutrinos of astrophysical origin over the energy range from $\sim 10^{12}$ eV to $\sim 10^{25}$ eV. In particular I shall review predictions of the diffuse neutrino intensity.…
The sources of the majority of the high-energy astrophysical neutrinos observed with the IceCube neutrino telescope at the South Pole are unknown. So far, only a gamma-ray blazar was compellingly associated with the emission of high-energy…
We study neutrino conversions in a recently envisaged source of high-energy neutrinos (E \geq 10^6 GeV), that is, in the vicinity of cosmological Gamma-Ray Burst fireballs (GRB). We consider the effects of flavor and spin-flavor conversions…
Recent astronomical observations reveal that Active Galactic Nuclei (AGN) are sources of high-energy radiation. For example, the Fermi-LAT and Hess telescopes have detected gamma-ray emissions from the cores of several types of AGN's. Even…
Existing and planned observatories for cosmic neutrinos open up a huge window in energy from 10^7 to 10^17 GeV. Here, we discuss in particular the possibilities to use extremely energetic cosmic neutrinos as a diagnostic of astrophysical…
High energy neutrinos with energy typically greater than tens of thousands of GeV may originate from several astrophysical sources. The sources may include, for instance, our galaxy, the active centers of nearby galaxies, as well as…
Ongoing experimental efforts to detect cosmic sources of high energy neutrinos are guided by the expectation that astrophysical accelerators of cosmic ray protons would also generate neutrinos through interactions with ambient matter and/or…
Active galactic nuclei (AGN) are known as sources of high energy gamma-rays. The emission probably results from non-thermal radiation of relativistic jets belonging to the AGN. Earlier investigations of these processes have suggested that…
Recent multimessenger studies have provided evidence for high-energy neutrino sources that are opaque to GeV-TeV gamma rays. We present model-independent studies on the connection between neutrinos and gamma rays in the active galaxy NGC…
Extremely high energy (EHE) neutrinos (with energies above $10^7$ GeV) are produced in interactions of the highest energy cosmic rays. A primary contribution to the EHE neutrino flux is expected from so-called cosmogenic neutrinos produced…
The observed very high energy spectra of distant blazars are well described by secondary gamma rays produced in line-of-sight interactions of cosmic rays with background photons. In the absence of the cosmic-ray contribution, one would not…