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Observations of soft gamma rays emanating from the Milky Way from SPI/\textit{INTEGRAL} reveal the annihilation of $\sim2\times10^{43}$ positrons every second in the Galactic bulge. The origin of these positrons, which annihilate to produce…

High Energy Astrophysical Phenomena · Physics 2017-12-27 Fiona H. Panther , Roland M. Crocker , Yuval Birnboim , Ivo R. Seitenzahl , Ashley J. Ruiter

We calculate the extragalactic diffuse emission originating from the up-scattering of cosmic microwave photons by energetic electrons and positrons produced in particle dark matter annihilation events at all redshifts and in all halos. We…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-22 Stefano Profumo , Tesla E. Jeltema

The Milky Way Galaxy glows with the soft gamma ray emission resulting from the annihilation of $\sim 5 \times 10^{43}$ electron-positron pairs every second. The origin of this vast quantity of antimatter and the peculiar morphology of the…

High Energy Astrophysical Phenomena · Physics 2017-02-22 Fiona H. Panther , Roland M. Crocker , Ivo R. Seitenzahl , Ashley J. Ruiter

We present a new analysis of the diffuse soft $\gamma$-ray emission towards the inner Galaxy as measured by the SPectrometer aboard the INTEGRAL satellite (SPI) with 16 years of data taking. The analysis implements a spatial template fit of…

High Energy Astrophysical Phenomena · Physics 2023-01-12 J. Berteaud , F. Calore , J. Iguaz , P. D. Serpico , T. Siegert

The Fermi Large Area Telescope observed an excess in gamma ray emission spectrum coming from the center of the Milky Way galaxy. This data reveals that a light Dark Matter (DM) candidate of mass in the range 31-40 GeV, dominantly decaying…

High Energy Physics - Phenomenology · Physics 2015-06-19 Dilip Kumar Ghosh , Subhadeep Mondal , Ipsita Saha

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…

High Energy Physics - Phenomenology · Physics 2015-06-12 Yang Bai , Meng Su , Yue Zhao

It was recently proposed that stable particles of charge $-2$, $O^{--}$, can exist and constitute dark matter after they bind with primordial helium in O-helium (OHe) atoms. We study here in details the possibility that this model provides…

High Energy Physics - Phenomenology · Physics 2014-01-22 Jean-René Cudell , Maxim Yu. Khlopov , Quentin Wallemacq

Although the annihilation of positrons towards the Galactic centre was established more than 50 years ago through the detection of a 511 keV $\gamma$-ray line, the origin of the positrons remains unknown. The $\gamma$-ray line should be…

High Energy Astrophysical Phenomena · Physics 2025-08-27 Jürgen Knödlseder , Karim Sabri , Pierre Jean , Peter von Ballmoos , Gerry Skinner , Werner Collmar

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…

Astrophysics · Physics 2007-05-23 U. Schwanke

INTEGRAL/SPI has recently observed a strong and extended emission resulting from electron-positron annihilation located in the Galactic center region, consistent with the Galactic bulge geometry, without any counterpart at high gamma-ray…

Astrophysics · Physics 2007-05-23 Stephane Schanne , Michel Casse , Bertrand Cordier , Jacques Paul

The e$^+$ e$^-$ annihilation line at 511 keV provides a unique probe for studying the distribution and origin of positrons in our Galaxy. The SPI spectrometer on INTEGRAL has observed this gamma-ray line for two decades. We analyze 20 years…

High Energy Astrophysical Phenomena · Physics 2025-10-29 Hiroki Yoneda , Thomas Siegert , Saurabh Mittal

The spectrum and morphology of gamma-rays from the Galactic Center and the spectrum of synchrotron emission observed from the Milky Way's radio filaments have each been interpreted as possible signals of $\sim$7-10 GeV dark matter particles…

High Energy Astrophysical Phenomena · Physics 2013-05-30 Dan Hooper , Wei Xue

The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has yielded unprecedented measurements of the soft gamma-ray spectrum of our Galaxy. Here we use those measurements to set constraints on dark matter (DM) that decays…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Ranjan Laha , Julian B. Muñoz , Tracy R. Slatyer

We propose a comprehensive theory of dark matter that explains the recent proliferation of unexpected observations in high-energy astrophysics. Cosmic ray spectra from ATIC and PAMELA require a WIMP with mass M_chi ~ 500 - 800 GeV that…

High Energy Physics - Phenomenology · Physics 2009-02-26 Nima Arkani-Hamed , Douglas P. Finkbeiner , Tracy R. Slatyer , Neal Weiner

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…

Astrophysics · Physics 2008-11-26 Hasan Yuksel

We compare the full-sky morphology of the 511 keV gamma ray excess measured by the INTEGRAL/SPI experiment to predictions of models based on dark matter (DM) scatterings that produce low-energy positrons: either MeV-scale DM that…

High Energy Physics - Phenomenology · Physics 2015-06-03 Aaron C. Vincent , Pierrick Martin , James M. Cline

The Positron Puzzle is a half-century old conundrum about the origin of the Galactic $\gamma$-ray emission line at photon energies of 511 keV, and the shape of its morphology, showing a bulge-to-disk luminosity ratio of $\sim 1$ - unlike…

High Energy Astrophysical Phenomena · Physics 2023-04-19 Thomas Siegert

The annihilation of dark matter (DM) in the Galaxy could produce specific imprints on the spectra of antimatter species in Galactic cosmic rays, which could be detected by upcoming experiments such as PAMELA and AMS02. Recent studies show…

Astrophysics · Physics 2008-11-26 P. Brun , G. Bertone , J. Lavalle , P. Salati , R. Taillet

Recently, the SPI spectrometer on the INTEGRAL satellite observed strong 511 keV line emission from the galactic bulge. Although the angular distribution (spherically symmetric with width of \sim 9 degree) of this emission is difficult to…

High Energy Physics - Phenomenology · Physics 2009-11-10 Dan Hooper , Lian-Tao Wang

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…

Astrophysics · Physics 2008-04-08 Douglas P. Finkbeiner