Related papers: Hypernovae and light dark matter as possible Galac…
Positron and electron cosmic rays provide a complementary way to study the galactic environment. The actual cosmic rays experiments, for instance PAMELA and HEAT, have presented very exciting results in this field. The observed positron…
Radioactive nuclei, especially those created in SN explosion, have long been suggested to be important contributors of galactic positrons. In this paper we describe the findings of three independent OSSE/SMM/TGRS studies of positron…
The origin and properties of the source of positrons annihilating in the Galactic Center is still a mystery. One of the criterion, which may discriminate between different mechanisms of positron production there, is the positron energy…
High energy positron annihilation is a viable mechanism to produce dark photons ($A^\prime$). This reaction plays a significant role in beam-dump experiments using experiments using multi-GeV electron-beams on thick targets by enhancing the…
In the past few decades, observations indicated that an unexplained high production rate of positrons (the strong 511 keV line) exists in the Milky Way center. By using the fact that a large amount of high density gas used to exist near the…
Two different model-independent mapping techniques have been applied to OSSE, SMM, TGRS and balloon data and reveal a feature in the 0.511 MeV electron-positron annihilation radiation pattern of our galaxy centered roughly at l=-2 deg. and…
High energy (~GeV) positrons are seen within cosmic rays and observation of a narrow line at 511 keV shows that positrons are annihilating in the galaxy after slowing down to ~keV energies or less. Our state of knowledge of the origin of…
High energy particles are produced by the annihilation of dark matter particles in our galaxy. These are presently searched for using balloon-borne antiproton and positron detectors and large area, deep underground neutrino telescopes. Dark…
The electron and positron cosmic rays puzzle has triggered a revolution in the field of astroparticle physics. Many hypotheses have been proposed to explain the unexpected rise of the positron fraction, observed by HEAT and PAMELA…
Excess microwave emission observed in the inner Galaxy (inner ~1 kpc) is consistent with synchrotron emission from highly relativistic electron-positron pairs produced by dark matter particle annihilation. More conventional sources for this…
Recent measurements made by the Alpha Magnetic Spectrometer (AMS) have detected accurate positron flux for energy range 1-1000 GeV. The energy spectrum can be best described by two source terms: the low-energy background diffusion term and…
Observations of the Galactic center region with the H.E.S.S. telescopes have established the existence of a steady, extended source of gamma-ray emission coinciding with the position of the super massive black hole Sgr A*. This is a…
SPI on INTEGRAL has provided spectra and a map of the sky in the emission from annihilations of positrons in the interstellar medium of our Galaxy. From high-resolution spectra we learned that a warm, partially-ionized medium is the site…
Several cosmic ray experiments have measured the positron fraction up to few hundred GeV. Their data have revealed an excess of positrons above 10 GeV that is not consistent with the secondary production of these particles in the…
The rapid rise in the cosmic ray positron fraction above 10 GeV, as measured by PAMELA and AMS, suggests the existence of nearby primary sources of high energy positrons, such as pulsars or annihilating/decaying dark matter. In contrast,…
The measurement of gamma rays from cosmic sources at MeV energies is one of the key tools for nuclear astrophysics, in its study of nuclear reactions and their impacts on objects and phenomena throughout the universe. Gamma rays trace…
A number of signals involving charged cosmic rays and high-energy photons have been interpreted as being due to annihilating dark matter. This article provides an overview of the experimental evidence and discusses in particular detections…
During a core-collapse supernova, absorption of anti-nu_e emitted from the proto-neutron star by protons in the hydrogen envelope produces neutrons and positrons. Neutron capture on protons and positron annihilation then produce gamma rays…
The annihilation of positrons in the Milky Way galaxy has been observed for $\sim 50$ years however the production sites of these positrons remains hard to identify. The observed morphology of positron annihilation gamma-rays provides…
The rise of the cosmic ray positron fraction with energy, as first observed with high confidence by PAMELA, implies that a large flux of high energy positrons has been recently (or is being currently) injected into the local volume of the…