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We use 15 years of $\gamma$-ray data from INTEGRAL/SPI in a refined investigation of the morphology of the Galactic bulge positron annihilation signal. Our spatial analysis confirms that the signal traces the old stellar population in the…

High Energy Astrophysical Phenomena · Physics 2021-10-20 Thomas Siegert , Roland M. Crocker , Oscar Macias , Fiona H. Panther , Francesca Calore , Deheng Song , Shunsaku Horiuchi

Ionized carbon is the main gas-phase reservoir of carbon in the neutral diffuse interstellar medium and its 158 micron fine structure transition [CII] is the most important cooling line of the diffuse interstellar medium (ISM). We combine…

We report on Cyg X-1 observations performed by the SPI telescope onboard the INTEGRAL mission and distributed over more than 6 years. We investigate the variability of the intensity and spectral shape of this peculiar source in the hard…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Elisabeth Jourdain , Jean-Pierre Roques , Julien Malzac

The TGRS (Transient Gamma-Ray Spectrometer) experiment is a high-resolution germanium detector launched on the WIND satellite on Nov. 1, 1994. Although primarily intended to study gamma-ray bursts and solar flares, TGRS also has the…

Gamma-ray line emission from radioactive decay of 60Fe provides constraints on nucleosynthesis in massive stars and supernovae. The spectrometer SPI on board INTEGRAL has accumulated nearly three years of data on gamma-ray emission from the…

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

Recent observations indicate that a high production rate of positrons (strong 511 keV line) and a significant amount of excess GeV gamma-ray exist in our Galactic bulge. The latter issue can be explained by $\sim 40$ GeV dark matter…

High Energy Astrophysical Phenomena · Physics 2016-02-29 Man Ho Chan

We have observed the [CII] 158 micron line emission from the Galactic plane (-10 deg < l < 25 deg, |b| <= 3 deg) with the Balloon-borne Infrared Carbon Explorer (BICE). The observed longitudinal distribution of the [CII] line emission is…

We present the results of new calculations of the energy spectra of cosmic ray electrons, positrons and also positron fraction under assumption that both electrons and positrons are generated by the same Galactic sources, which accelerate…

High Energy Astrophysical Phenomena · Physics 2019-05-17 Nikolay Volkov , Anatoly Lagutin , Alexander Tyumentsev

Measurement and astrophysical interpretation of characteristic gamma-ray lines from nucleosynthesis was one of the prominent science goals of the INTEGRAL mission and in particular its spectrometer SPI. Emission from 26Al and from 60Fe…

Instrumentation and Methods for Astrophysics · Physics 2021-12-10 Roland Diehl , Martin G. H. Krause , Karsten Kretschmer , Michael Lang , Moritz M. M. Pleintinger , Thomas Siegert , Wei Wang , Laurent Bouchet , Pierrick Martin

A common idea for the origin of the Galactic diffuse X-ray emission, particularly that of the iron lines from neutral and highly ionized atoms, is a superposition of many cataclysmic variables and coronally active binaries. In this…

High Energy Astrophysical Phenomena · Physics 2015-06-03 K. K. Nobukawa , M. Nobukawa , H. Uchiyama , T. G. Tsuru , K. Torii , T. Tanaka , D. O. Chernyshov , Y. Fukui , V. A. Dogiel , K. Koyama

We analyze the first two years of data from the Fermi Gamma Ray Space Telescope from the direction of the inner 10 degrees around the Galactic Center with the intention of constraining, or finding evidence of, annihilating dark matter. We…

High Energy Physics - Phenomenology · Physics 2015-03-17 Dan Hooper , Lisa Goodenough

The 511 keV electron-positron annihilation feature near the galactic center has been detected for more than half a century, yet its origin remains a mystery. In this paper, we describe a concept for a balloon-borne 511 keV $\gamma$-ray…

We want to estimate whether the positrons produced by the beta plus decay of 26Al, 44Ti and 56Ni synthesised in massive stars and supernovae are sufficient to explain the 511 keV annihilation emission observed in our Galaxy. Such a…

High Energy Astrophysical Phenomena · Physics 2014-05-08 A. Alexis , P. Jean , P. Martin , K. Ferriere

We calculate the expected flux of gamma-ray and radio emission from the LMC due to neutralino annihilation. Using rotation curve data to probe the density profile and assuming a minimum disk, we describe the dark matter halo of the LMC…

Astrophysics · Physics 2008-11-26 Argyro Tasitsiomi , Jennifer Gaskins , Angela V. Olinto

Very high-energy gamma-rays (VHE; E>100 GeV) have been detected from the direction of the Galactic Centre up to energies E>10 TeV. Up to now, the origin of this emission is unknown due to the limited positional accuracy of the observing…

Astrophysics of Galaxies · Physics 2010-02-12 A. Abramowski , S. Gillessen , D. Horns , H. -S. Zechlin

Well-motivated models of dark matter often result in a population of electrons and positrons within galaxies produced through dark matter annihilation -- usually in association with gamma rays. As they diffuse through galactic magnetic…

High Energy Physics - Phenomenology · Physics 2024-02-23 Mitchell J. Weikert , Matthew R. Buckley

The detection of gamma-rays from the source HESS J1745-290 in the Galactic Center (GC) region with the H.E.S.S. array of Cherenkov telescopes in 2004 is presented. After subtraction of the diffuse gamma-ray emission from the GC ridge, the…

Astrophysics · Physics 2012-08-27 H. E. S. S. collaboration , : , F. A. Aharonian

PAMELA and ATIC recently reported an excess in e+e- cosmic rays. We show that if it is due to Dark Matter annihilations, the associated gamma-ray flux and the synchrotron emission produced by e+e- in the galactic magnetic field violate HESS…

Astrophysics · Physics 2009-10-09 Gianfranco Bertone , Marco Cirelli , Alessandro Strumia , Marco Taoso

Studies based on imaging the annihilation of the electron (e$^{-}$) and its antiparticle positron (e$^{+}$) open up several interesting applications in nuclear medicine and fundamental research. The annihilation process involves both the…

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