Related papers: The neutrino background from non-jetted active gal…
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…
Active galactic nuclei (AGN) can accelerate protons to energies of $\sim$10-100 TeV, with secondary production of high-energy neutrinos. If the acceleration is driven by magnetized turbulence, the main properties of the resulting proton and…
The first high-energy neutrino source identified by IceCube was a blazar -- an active galactic nucleus driving a relativistic jet towards Earth. Jets driven by accreting black holes are commonly assumed to be needed for high-energy neutrino…
We report three searches for high energy neutrino emission from astrophysical objects using data recorded with IceCube between 2011 and 2020. Improvements over previous work include new neutrino reconstruction and data calibration methods.…
The origin of diffuse high-energy neutrinos from TeV to PeV energies detected by IceCube Observatory remains a mystery. In our previous work, we have shown that hadronuclear (p-p) interactions in AGN jets could be important and generate…
IceCube recently reported the observation of TeV neutrinos from the nearby Seyfert galaxy NGC~1068, and the corresponding neutrino flux is significantly higher than the upper limit implied by observations of GeV-TeV gamma rays. This…
Observational information on high-energy astrophysical neutrinos is being continuously collected by the IceCube observatory. However, the sources of neutrinos are still unknown. In this study, we use radio very-long-baseline interferometry…
The recent discovery of high-energy cosmic neutrinos by the IceCube neutrino observatory opens up a new field in physics, the field of neutrino astronomy. Using the IceCube neutrino detector we plan to search for high-energy neutrinos…
The steep spectrum of neutrinos measured by IceCube extending from >1 PeV down to ~10 TeV has an energy flux now encroaching on the Fermi isotropic GeV background. We examine several implications starting from source energetics requirements…
Astrophysical neutrinos from Active Galactic Nuclei (AGN) offer a unique window into high-energy particle acceleration in obscured environments. The nearby Type II Seyfert galaxy NGC 1068 is a compelling example, exhibiting evidence of a…
The TeV neutrino signal observed by IceCube from the active galactic nucleus (AGN) NGC 1068 can probe its innermost coronal regions. If these neutrinos originate from hadrons accelerated within a magnetized turbulent corona, their intensity…
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…
Various observations are revealing the widespread occurrence of fast and powerful winds in active galactic nuclei (AGNs) that are distinct from relativistic jets, likely launched from accretion disks and interacting strongly with the gas of…
Active Galactic Nuclei (AGN) are powerful astronomical objects with very high luminosities. Theoretical arguments suggest that these objects are capable of accelerating particles to energies of 10$^{20}$ eV. In environments with matter or…
The recent detection of TeV neutrinos from some nearby Seyfert galaxy (e.g., NGC1068) by IceCube suggests that active galactic nuclei (AGNs) could make a significant contribution to diffuse astrophysical neutrinos. The absence of TeV…
The origin of the diffuse astrophysical neutrino flux measured by the IceCube Observatory remains largely unknown. Although NGC 1068 and TXS 0506+056 have been identified as potential neutrino sources, the diffuse flux of neutrinos must…
The IceCube project transformed a cubic kilometer of transparent, natural Antarctic ice into a Cherenkov detector. It discovered neutrinos of TeV-PeV energy originating beyond our Galaxy with an energy flux that exceeds the one of…
IceCube has observed an excess of neutrino events over expectations from the isotropic background from the direction of NGC 1068. The excess is inconsistent with background expectations at the level of $2.9\sigma$ after accounting for…
High-energy neutrinos are detected by the IceCube Observatory in the direction of NGC 1068, the archetypical type II Seyfert galaxy. The neutrino flux, surprisingly, is more than an order of magnitude higher than the $\gamma$-ray upper…
IceCube observations point to Active Galactic Nuclei (AGN) as promising contributors to the observed astrophysical neutrino flux. Close to the central black hole, protons can be accelerated through magnetic reconnection to very high…