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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

Assuming Galactic positrons do not go far before annhilating, a difference between the observed 511 keV annihilation flux distribution and that of positron production, expected from beta-plus decay in Galactic iron nucleosynthesis, was…

High Energy Astrophysical Phenomena · Physics 2009-09-02 R. E. Lingenfelter , J. C. Higdon , R. E. Rothschild

The majority of gamma-ray emission from Galactic dark matter annihilation is likely to be detected as a contribution to the diffuse gamma-ray background. I show that dark matter substructure in the halo of the Galaxy induces characteristic…

Astrophysics · Physics 2011-07-13 Jennifer M. Siegal-Gaskins

The origin of the cosmic gamma-ray background (CGB) is a longstanding mystery in high-energy astrophysics. Possible candidates include ordinary astrophysical objects such as unresolved blazars, as well as more exotic processes such as dark…

Astrophysics · Physics 2008-11-26 Shin'ichiro Ando , Eiichiro Komatsu , Takuro Narumoto , Tomonori Totani

In this letter, we suggest that a nearby clump of 600-1000 GeV neutralinos may be responsible for the excesses recently observed in the cosmic ray positron and electron spectra by the PAMELA and ATIC experiments. Although neutralino dark…

High Energy Physics - Phenomenology · Physics 2009-07-30 Dan Hooper , Albert Stebbins , Kathryn M. Zurek

Fermi measurements of the high-latitude gamma-ray background strongly constrain a decaying-dark-matter origin for the 1--100 GeV Galactic positron anomaly measured with PAMELA. Inverse-Compton scattering of the microwave background by the…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Martin Pohl , David Eichler

The EGRET excess of diffuse Galactic gamma rays shows all the features expected from dark matter annihilation (DMA): a spectral shape given by the fragmentation of mono-energetic quarks, which is the same in all sky directions and an…

Astrophysics · Physics 2008-01-09 Iris Gebauer

We propose a novel mechanism to explain the positron excesses, which are observed by satellite-based telescopes including PAMELA and AMS-02, in dark matter (DM) scenarios. The novelty behind the proposal is that it makes direct use of DM…

High Energy Physics - Phenomenology · Physics 2018-05-09 Doojin Kim , Jong-Chul Park , Seodong Shin

We show that the cosmic-ray positron excess measured by PAMELA and AMS could be induced by Dark Matter annihilations in a local over-density. In such a context leptophilic DM is not needed and good fits to positron data, in agreement with…

High Energy Physics - Phenomenology · Physics 2015-06-16 A. Hektor , M. Raidal , A. Strumia , E. Tempel

Clusters of galaxies are enriched with positrons from jets of active galactic nuclei (AGNs) or from the interaction of cosmic rays with the intracluster gas. We follow the cooling of these positrons and show that their eventual annihilation…

Astrophysics · Physics 2009-11-07 Steven Furlanetto , Abraham Loeb

The Chinese satellite Wukong, also known as the DArk Matter Particle Explorer (DAMPE), has released its observation data of the cosmic ray (CR) electrons and positrons. The data shows an excess in the energy spectrum up to TeV energy, and…

High Energy Astrophysical Phenomena · Physics 2018-12-19 Hong-Bo Jin , Bin Yue , Xin Zhang , Xuelei Chen

Several cosmic ray experiments have measured excesses in electrons and positrons, relative to standard backgrounds, for energies from ~ 10 GeV - 1 TeV. These excesses could be due to new astrophysical sources, but an explanation in which…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Spencer Chang , Lisa Goodenough

Several explanations for the existence of Ultra High Energy Cosmic Rays invoke the idea that they originate from the decay of massive particles created in the reheating following inflation. It has been suggested that the decay products can…

Astrophysics · Physics 2009-10-31 Gustavo Medina Tanco , Alan A. Watson

Anisotropy in the arrival direction distribution of ultrahigh-energy cosmic rays (UHECRs) produced by powerful sources is numerically evaluated. We show that, taking account of the Galactic magnetic field, nondetection of significant…

High Energy Astrophysical Phenomena · Physics 2016-01-22 Hajime Takami , Kohta Murase , Charles D. Dermer

The observed anomalous excess of high-energy cosmic ray (CR) positrons is widely discussed as possible indirect evidence for dark matter (DM). However, any source of cosmic positrons is inevitably the source of gamma radiation. The least…

High Energy Physics - Phenomenology · Physics 2020-04-14 Konstantin M. Belotsky , Airat Kh. Kamaletdinov , Ekaterina S. Shlepkina , Maxim L. Solovyov

Dark matter particles may be captured by a star and then thermalized in the star's core. At the end of its life a massive star collapses suddenly and a compact object is formed. The dark matter particles redistribute accordingly. In the…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Rui-Zhi Yang , Yi-Zhong Fan , Roni Waldman , Jin Chang

Recent results from the PAMELA experiment indicate an excess in the positron spectrum above 10 GeV, but anti-proton data are consistent with the expected astrophysical backgrounds. We propose a scenario that reproduces these features. Dark…

High Energy Physics - Phenomenology · Physics 2009-09-24 Daniel J. Phalen , Aaron Pierce , Neal Weiner

We investigate the possibility of secondary production as the source of cosmic ray (CR) positrons, taking into account observed electron and antiproton spectra and allowing that the reported steepening in the AMS-02 positron spectrum may be…

High Energy Astrophysical Phenomena · Physics 2020-05-27 Rebecca Diesing , Damiano Caprioli

The flux of cosmic-ray high-energy positrons has recently been measured by AMS with unprecedented precision. This flux is well above the expectation from secondary positrons made by the observed fluxes of nuclear cosmic rays impinging on…

High Energy Physics - Phenomenology · Physics 2019-09-05 A. De Rújula

Dark matter annihilation in Galactic substructure produces diffuse gamma-ray emission of remarkably constant intensity across the sky, and in general this signal dominates over the smooth halo signal at angles greater than a few tens of…

High Energy Astrophysical Phenomena · Physics 2009-07-02 Jennifer M. Siegal-Gaskins