Related papers: Unstable Relics as a Source of Galactic Positrons
Feebly interacting particles with masses with O(10-100) MeV can be copiously produced by core-collapse supernovae (SNe). In this paper we consider the case of MeV-ish sterile neutrinos and dark photons mixed with ordinary neutrinos and…
If massive sterile neutrinos exist, their decays into photons and/or electron-positron pairs may give rise to observable consequences. We consider the possibility that MeV sterile neutrino decays lead to the diffuse positron annihilation…
The observed 511 keV line from the Galactic Bulge is a real challenge for theoretical astrophysics: despite a lot of suggested mechanisms, there is still no convincing explanation and the origin of the annihilated positrons remains unknown.…
We derive constraints on the relic abundance of a generic particle of mass $\sim~1-10^{14}$ TeV which decays into neutrinos at cosmological epochs, using data from the Fr\'ejus and IMB nucleon decay detectors and the Fly's Eye air shower…
We calculate the fluxes of neutrinos and gamma rays from interactions of cosmic rays with interstellar matter in our galaxy. We use EPOS-LHC, SIBYLL and GHEISHA to obtain the yield of these particles in proton, helium and iron collisions at…
We consider the possibility that a large fraction of the ultrahigh energy cosmic rays are decay products of Z bosons which were produced in the scattering of ultrahigh energy cosmic neutrinos on cosmological relic neutrinos. We compare the…
The discovery of neutrino masses implies the existence of new particles, the sterile neutrinos. These particles can have important implications for cosmology and astrophysics. A sterile neutrino with mass of a few keV can account for the…
A sterile neutrino with mass of several keV can account for cosmological dark matter, as well as explain the observed velocities of pulsars. We show that X-rays produced by the decays of these relic sterile neutrinos can boost the…
The anomalous bump in the cosmic ray positron to electron ratio at $10 GeV$ can be explained as being a component from a point source that was originally harder than the primary electron background and degrades due to synchrotron and…
We consider sterile neutrinos with rest masses ~0.2 GeV. Such sterile neutrinos could augment core collapse supernova shock energies by enhancing energy transport from the core to the vicinity of the shock front. The decay of these…
A halo model with heavy relic neutrinos N belonging to a fourth generation and their annihilations in galactic halo may explain the recent evidence of diffused gamma (GeV) radiation around galactic plane. We considered a neutrino mass in…
We consider long-lived relic particles as the source of the PeV-scale neutrinos detected at the IceCube observatory over the last six years. We derive the present day neutrino flux, including primary neutrinos from direct decays, secondary…
Extragalactic and galactic cosmic rays scatter with the cosmic neutrino background during propagation to Earth, yielding a flux of relic neutrinos boosted to larger energies. If an overdensity of relic neutrinos is present in galaxies, and…
We consider heavy stable neutral particles in the context of supergravity and show that a gravitationally suppressed inflaton decay can produce such particles in cosmologically interesting abundances within a wide mass range $10^3 {\rm GeV}…
Extinct radio pulsars, in which stationary, self-sustaining generation of a relativistic electron-positron plasma becomes impossible when rotation brakes down, can be sources of a subrelativistic flux of positrons and electrons. We assume…
The annihilation of new dark matter candidates with masses $m_X$ in the MeV range may account for the galactic positrons that are required to explain the 511 keV $\gamma$-ray flux from the galactic bulge. We study the impact of MeV-mass…
We revisit the upper limits on the abundance of unstable massive relic particles provided by the success of Big-Bang Nucleosynthesis calculations. We use the cosmic microwave background data to constrain the baryon-to-photon ratio, and…
Sterile neutrinos with keV masses can constitute all or part of the cosmological dark matter. The electroweak-singlet fermions, which are usually introduced to explain the masses of active neutrinos, need not be heavier than the electroweak…
The bulge of our Galaxy is illuminated by the 0.511 MeV gamma-ray line flux from annihilations of nonrelativistic positrons. The emission is strongly concentrated at the Galactic Center, in contrast to gamma-ray maps tracing nucleosynthesis…
We show that a tangle of light superconducting strings in the Milky Way could be the source of the observed 511 KeV emission from electron-positron annihilation in the Galactic bulge. The scenario predicts a flux that is in agreement with…