相关论文: Positron Annihilation in the Milky Way and beyond
We discuss the gamma-ray signal from dark matter annihilation in our Galaxy and in external objects, namely the Large Magellanic Cloud, the Andromeda Galaxy (M31) and M87. We derive predictions for the fluxes in a low energy realization of…
Both the robust INTEGRAL 511 keV gamma-ray line and the recent tentative hint of the 135 GeV gamma-ray line from Fermi-LAT have similar signal morphologies, and may be produced from the same dark matter annihilation. Motivated by this…
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.…
Energetic positrons produced in annihilation or decay of dark matter particles in the Milky Way can serve as an important indirect signature of dark matter. Computing the positron flux expected in a given dark matter model involves solving…
We discuss the possibility that the recent detection of 511 keV gamma-rays from the galactic bulge, as observed by INTEGRAL, is a consequence of low mass (~MeV) particle dark matter annihilations. We discuss the type of halo profile favored…
We present a search for gamma-ray emission from the direction of the newly discovered dwarf galaxy Reticulum II. Using Fermi-LAT data, we detect a signal that exceeds expected backgrounds between ~2-10 GeV and is consistent with…
It has been recently proposed that the observed 511 keV emission from the Galactic bulge could be the product of very light (1-100 MeV) annihilating dark matter particles. Other possible explanations for this signal are associated with…
The indirect detection of dark matter requires that dark matter annihilation products be discriminated from conventional astrophysical backgrounds. Here, we re-analyze GeV-band gamma-ray observations of the prominent Milky Way dwarf…
Gamma ray emission of 511 keV lines arising from electron-positron annihilation has been detected from the Galaxy since the 70s. Spatially resolved observations using the INTEGRAL satellite have shown its full sky distribution to be…
The intense 0.511 MeV gamma-ray line emission from the Galactic Center observed by INTEGRAL requires a large annihilation rate of nonrelativistic positrons. If these positrons are injected at even mildly relativistic energies, higher-energy…
Observations of nearby galaxies and galaxy clusters have reported an unexpected X-ray emission line around 3.5 kilo-electron volts (keV). Proposals to explain this line include decaying dark matter$-$in particular, that the decay of sterile…
In this paper I present the detail estimations for the width of the 511 keV line produced by a mechanism when dark matter is represented by macroscopically large dense nuggets. I argue that the width of 511 keV emission in this mechanism is…
If the dark matter in the Universe is made of weakly self-interacting particles, they may self-annihilate and emit gamma-rays. We use high resolution numerical simulations to estimate directly the annihilation flux from the central regions…
Dark Matter annihilation holds great potential for directly probing the clumpiness of the Galactic halo that is one of the key predictions of the Cold Dark Matter paradigm of hierarchical structure formation. Here we review the gamma-ray…
The positron fraction in cosmic rays was found to be a steadily increasing in function of energy, above $\sim$ 10 GeV. This behaviour contradicts standard astrophysical mechanisms, in which positrons are secondary particles, produced in the…
Neutron-rich material ejected from neutron star-neutron star (NS-NS) and neutron star-black hole (NS-BH) binary mergers is heated by nuclear processes to temperatures of a few hundred keV, resulting in a population of electron-positron…
The presence of dark matter is nowadays widely supported by a large body of astronomical and cosmological observations. A large amount of dark matter is expected to be present in the central region of the Milky Way. Very-high-energy (>100…
Dark matter annihilations in the Galactic halo inject relativistic electrons and positrons which in turn generate a synchrotron radiation when interacting with the galactic magnetic field. We calculate the synchrotron flux for various 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…
Reticulum II (Ret II) is a satellite galaxy of the Milky Way and presents a prime target to investigate the nature of dark matter (DM) because of its high mass-to-light ratio. We evaluate a dedicated INTEGRAL observation campaign data set…