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We model the electrons/positrons produced by dark matter annihilations in the colliding galaxy cluster system 1E0657-56 (the bullet cluster). These charged particles, confined by the Magnetic field, clearly trace the path of the bullet,…

Astrophysics · Physics 2007-10-26 Xiao-Jun Bi , HongSheng Zhao

The status of the analysis of the electron/positron annihilation radiation performed by INTEGRAL/SPI in the 4th GALACTIC QUADRANT is reported. We use data from the first two Galactic Center Deep Exposures (GCDE) and from the Galactic Plane…

Pulsars are believed to be sources of relativistic electrons and positrons. The abundance of detections of gamma-ray millisecond pulsars by Fermi Large Area Telescope coupled with their light curve characteristics that imply copious pair…

High Energy Astrophysical Phenomena · Physics 2015-06-23 C. Venter , A. Kopp , P. L. Gonthier , A. K. Harding , I. Büsching

Recently, data of taken with the OSSE experiment have been combined with scanning observations by TGRS and SMM to produce maps of the narrow Galactic 511 keV line emission (Purcell et al. 1997). A modelling of the combined data give…

Astrophysics · Physics 2007-05-23 Martin Pohl

Annihilation of dark matter can result in the production of stable Standard Model particles including electrons and positrons that, in the presence of magnetic fields, lose energy via synchrotron radiation, observable as radio emission.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Emma Storm , Tesla E. Jeltema , Stefano Profumo , Lawrence Rudnick

The positron excess in cosmic rays has stimulated a lot of interests in the last decade. The dark matter origin of the extra positrons has attracted great attention. However, the $\gamma$-ray search set very stringent constraints on the…

High Energy Astrophysical Phenomena · Physics 2024-11-07 Xing-Jian Lv , Xiao-Jun Bi , Kun Fang , Peng-Fei Yin , Meng-Jie Zhao

The high positron production rate required to explain the flux of 511 keV gamma rays from the galactic center has inspired many models in which dark matter creates positrons. These models include the annihilation of light dark matter and…

High Energy Physics - Phenomenology · Physics 2013-05-22 Andrew R. Frey , Nicholas B. Reid

In this paper, we study the flux of electrons and positrons injected by pulsars and by annihilating or decaying dark matter in the context of recent ATIC, PAMELA, Fermi, and HESS data. We review the flux from a single pulsar and derive the…

High Energy Astrophysical Phenomena · Physics 2009-09-17 Dmitry Malyshev , Ilias Cholis , Joseph Gelfand

Secondary positrons are produced by spallation of cosmic rays within the interstellar gas. Measurements have been typically expressed in terms of the positron fraction, which exhibits an increase above 10 GeV. Many scenarios have been…

Astrophysics · Physics 2009-10-06 T. Delahaye , F. Donato , N. Fornengo , J. Lavalle , R. Lineros , P. Salati , R. Taillet , .

Recent advances in gamma-ray cosmic ray, infrared and radio astronomy have allowed us to develop a significantly better understanding of the galactic medium properties in the last few years. In this work using the DRAGON code, that…

High Energy Astrophysical Phenomena · Physics 2014-03-05 Maryam Tavakoli , Ilias Cholis , Carmelo Evoli , Piero Ullio

Pulsars have been invoked to explain the origin of recently observed high-energy Galactic cosmic-ray positrons. Since the positron propagation distance decreases with energy, the number of pulsars that can contribute to the observed…

High Energy Astrophysical Phenomena · Physics 2018-07-18 Ilias Cholis , Tanvi Karwal , Marc Kamionkowski

The first detected gamma-ray line originating from outside the solar system is the 511 keV emission from the center of our Galaxy. The widely accepted explanation attributes this signal to electron-positron annihilation. However, despite…

Instrumentation and Methods for Astrophysics · Physics 2026-05-12 J. Va'vra

Observations of the INTEGRAL satellite revealed the presence of yet unexplained excess in the central region of the Galaxy at the energies around 511 keV. These gamma-rays are produced in the process of positron annihilation, the needed…

High Energy Astrophysical Phenomena · Physics 2016-11-15 Maxim S. Pshirkov

We consider the angular distribution of the photon signal which could arise from velocity-dependent dark matter annihilation within the Galactic bulge. We find that, for the case of Sommerfeld-enhanced annihilation, dark matter annihilation…

High Energy Physics - Phenomenology · Physics 2022-11-23 Kenny Kiriu , Jason Kumar , Jack Runburg

The annihilation of neutralino dark matter in the Galactic Center (GC) may result in radio signals that can be used to detect or constrain the dark matter halo density profile or dark matter particle properties. At the Galactic Center, the…

Astrophysics · Physics 2011-05-12 Roberto Aloisio , Pasquale Blasi , Angela V. Olinto

Neutralino annihilation in the Galactic halo is the most definite observational signature proposed for indirect registration of the SUSY Dark Matter (DM) candidate particles. The corresponding annihilation signal (in the form of gamma-rays,…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Veniamin Berezinsky , Vyacheslav Dokuchaev , Yury Erohenko

The annihilation of neutralino dark matter may result in observable signals in different wavelength. In the present paper we will discuss the effect of neutralino annihilation in the halo of our Galaxy and in its center. According to high…

Astrophysics · Physics 2016-11-09 Roberto Aloisio

The balloon-borne Compton Spectrometer and Imager (COSI) had a successful 46-day flight in 2016. The instrument is sensitive to photons in the energy range $0.2$-$5$ MeV. Compton telescopes have the advantage of a unique imaging response…

Recent analyses of the anisotropy of cosmic rays at $10^{18}$ eV (the AGASA and SUGAR data) show significant excesses from regions close to the Galactic Centre and Cygnus. Our aim is to check whether such anisotropies can be caused by…

Astrophysics · Physics 2008-11-26 W. Bednarek , M. Giller , M. Zielinska

The WMAP experiment has revealed an excess of microwave emission from the region around the center of our Galaxy. It has been suggested that this signal, known as the ``WMAP Haze'', could be synchrotron emission from relativistic electrons…

Astrophysics · Physics 2008-11-26 Dan Hooper , Douglas P. Finkbeiner , Gregory Dobler