Related papers: Novae in gamma-rays
Accretion onto neutron stars (NSs) in X-ray pulsars (XRPs) results in intense X-ray emission, and under specific conditions, high-energy nuclear interactions that produce gamma-ray photons at discrete energies. These interactions are…
Recent studies suggest that pulsars could be strong sources of TeV muon neutrinos provided positive ions are accelerated by pulsar polar caps to PeV energies. In such a situation muon neutrinos are produced through the delta resonance in…
We consider the result of acceleration of heavy ions in the slot gap potential of a very young pulsar with a hot polar cap. Photodisintegration of the heavy ions in the radiation field of the polar cap and pulsar surface gives rise to a…
In the cosmological blast-wave model for gamma ray bursts (GRBs), high energy (> 10 GeV) gamma-rays are produced either through Compton scattering of soft photons by ultrarelativistic electrons, or as a consequence of the acceleration of…
Recent ground based and space telescopes that detect high energy photons from a few up to hundreds of gigaelectron volts (GeV) have opened a new window on the universe. However, because of the relatively poor angular resolution of these…
Cosmic rays of energies up to a few PeV are believed to be of galactic origin, yet individual sources have still not been firmly identified. Due to inelastic collisions with the interstellar gas, cosmic-ray nuclei produce a diffuse flux of…
We present a detailed study of the gamma-ray emission from the direction of the star-forming region W30 based on a decade of the Fermi Large Area Telescope data in the 0.3-300 GeV photon energy range. The morphological and spectral analyses…
Relativistic outflows with neutrons inevitably lead to inelastic collisions, and resulting subphotospheric gamma rays may explain prompt emission of gamma-ray bursts. In this model, hadronuclear, quasithermal neutrinos in the 10-100 GeV…
When a star undergoes core collapse, a vast amount of energy is released in a ~10 s long burst of neutrinos of all species. Inverse beta decay in the star's hydrogen envelope causes an electromagnetic cascade which ultimately results in a…
Novae had not been widely considered as high-energy (>100 MeV) gamma-ray sources before the launch of the Fermi Large Area Telescope (LAT). In March 2010, the LAT made the first gamma-ray detection of a nova in the symbiotic binary V407…
We study the gamma-ray emissions from an outer-magnetospheric potential gap around a rotating neutron star. Migratory electrons and positrons are accelerated by the electric field in the gap to radiate copious gamma-rays via curvature…
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…
We study the production of sterile neutrinos in supernovae, focusing in particular on the keV--MeV mass range, which is the most interesting range if sterile neutrinos are to account for the dark matter in the Universe. Focusing on the…
The supernova remnant Cassiopeia A is a prime candidate for accelerating cosmic ray protons and ions. Gamma rays have been observed at GeV and TeV energies, which indicates hadronic interactions, but they could also be caused by…
If supernova remnants (SNRs) are the sites of cosmic-ray acceleration, the associated nuclear interactions should result in observable fluxes of TeV gamma-rays from the nearest SNRs. Measurements of the gamma-ray flux from six nearby,…
Recently, gamma-ray telescopes AGILE and Fermi observed several middle-aged supernova remnants (SNRs) interacting with molecular clouds. It is likely that their gamma rays arise from the decay of neutral pions produced by the inelastic…
Gamma-ray bursts are known to be sources of high-energy gamma rays, and are likely to be sources of high-energy cosmic rays and neutrinos. Following a short review of observations of GRBs at multi-MeV energies and above, the physics of…
A signal of high-energy extraterrestrial neutrinos from unknown source(s) was recently discovered by the IceCube experiment. Neutrinos are always produced together with gamma-rays, but the gamma-ray flux from extragalactic sources is…
We treat high-energy neutrino production in GRBs. Detailed calculations of photomeson neutrino production are presented for the collapsar model, where internal nonthermal synchrotron radiation is the primary target photon field, and the…
Supernovae (SNe) are the most fascinating objects in astronomy and are intensely investigated. However, many mysteries such as nucleosynthesis and the origin of SNe Ia remain unsolved. Although the thermonuclear explosion of a…