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After the PAMELA finding of an increasing positron fraction above 10 GeV, the experimental evidence for the presence of a new electron and positron spectral component in the cosmic ray zoo has been recently confirmed by Fermi-LAT. We show…

High Energy Astrophysical Phenomena · Physics 2017-08-23 Daniele Gaggero , Dario Grasso

The recent observations of the positron fraction in cosmic rays by PAMELA indicate that the fraction of positrons to the total electronic component in cosmic rays initially decreases in the energy region 1-10 GeV and increases thereafter.…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-11 R. Cowsik , B. Burch

The measurements of electrons from cosmic rays have begun a new era a few years ago with high precision experiments like PAMELA and Fermi-LAT. The positron fraction seems to indicate an unknown component above the standard background…

High Energy Astrophysical Phenomena · Physics 2017-08-23 Jonathan Pochon

We measured separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope. Because the instrument does not have an onboard magnet, we distinguish the two species by exploiting the Earth's shadow, which is offset in…

High Energy Astrophysical Phenomena · Physics 2012-03-28 The Fermi LAT Collaboration , M. Ackermann , M. Ajello , A. Allafort , W. B. Atwood , L. Baldini , G. Barbiellini , D. Bastieri , K. Bechtol , R. Bellazzini , B. Berenji , R. D. Blandford , E. D. Bloom , E. Bonamente , A. W. Borgland , A. Bouvier , J. Bregeon , M. Brigida , P. Bruel , R. Buehler , S. Buson , G. A. Caliandro , R. A. Cameron , P. A. Caraveo , J. M. Casandjian , C. Cecchi , E. Charles , A. Chekhtman , C. C. Cheung , J. Chiang , S. Ciprini , R. Claus , J. Cohen-Tanugi , J. Conrad , S. Cutini , A. de Angelis , F. de Palma , C. D. Dermer , S. W. Digel , E. do Couto e Silva , P. S. Drell , A. Drlica-Wagner , C. Favuzzi , S. J. Fegan , E. C. Ferrara , W. B. Focke , P. Fortin , Y. Fukazawa , S. Funk , P. Fusco , F. Gargano , D. Gasparrini , S. Germani , N. Giglietto , P. Giommi , F. Giordano , M. Giroletti , T. Glanzman , G. Godfrey , I. A. Grenier , J. E. Grove , S. Guiriec , M. Gustafsson , D. Hadasch , A. K. Harding , M. Hayashida , R. E. Hughes , G. Jóhannesson , A. S. Johnson , T. Kamae , H. Katagiri , J. Kataoka , J. Knödlseder , M. Kuss , J. Lande , L. Latronico , M. Lemoine-Goumard , M. Llena Garde , F. Longo , F. Loparco , M. N. Lovellette , P. Lubrano , G. M. Madejski , M. N. Mazziotta , J. E. McEnery , P. F. Michelson , W. Mitthumsiri , T. Mizuno , A. A. Moiseev , C. Monte , M. E. Monzani , A. Morselli , I. V. Moskalenko , S. Murgia , T. Nakamori , P. L. Nolan , J. P. Norris , E. Nuss , M. Ohno , T. Ohsugi , A. Okumura , N. Omodei , E. Orlando J. F. Ormes , M. Ozaki , D. Paneque , D. Parent , M. Pesce-Rollins , M. Pierbattista , F. Piron , G. Pivato , T. A. Porter , S. Rainò , R. Rando , M. Razzano , S. Razzaque , A. Reimer , O. Reimer , T. Reposeur , S. Ritz , R. W. Romani , M. Roth , H. F. -W. Sadrozinski , C. Sbarra , T. L. Schalk , C. Sgrò , E. J. Siskind , G. Spandre , P. Spinelli , A. W. Strong , H. Takahashi , T. Takahashi , T. Tanaka , J. G. Thayer , J. B. Thayer , L. Tibaldo , M. Tinivella , D. F. Torres , G. Tosti , E. Troja , Y. Uchiyama , T. L. Usher , J. Vandenbroucke , V. Vasileiou , G. Vianello , V. Vitale , A. P. Waite , B. L. Winer , K. S. Wood , M. Wood , Z. Yang , S. Zimmer

A combined interpretation of the CALET $e^+\, +\, e^-$ spectrum up to 3 TeV and the AMS-02 positron spectrum up to 500 GeV was performed and the results are discussed. To parametrize the background electron flux, we assume a smoothly broken…

High Energy Astrophysical Phenomena · Physics 2018-10-23 S. Bhattacharyya , H. Motz , Y. Asaoka , S. Torii

The observations of the total electronic component and the positron fraction in cosmic rays by the FERMI, HESS, ATIC, and PAMELA instruments are studied with analytical propagation models, both for a set of discrete sources and for a…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-15 R. Cowsik , B. Burch

The Fermi Large Area Telescope (LAT) has provided the measurement of the high energy cosmic ray electrons plus positrons (CRE) spectrum with unprecedented accuracy form 20 GeV to 1 TeV. Recently this range has been extended down to ~ 7 GeV.…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Giuseppe Di Bernardo , Daniele Gaggero , Dario Grasso

The flux of positrons and electrons ($e^+ + e^-$) has been measured by the $Fermi$ Large Area Telescope (LAT) in the energy range between 7 GeV and 2 TeV. We discuss a number of interpretations of Pass 8 $Fermi$-LAT $e^+ + e^-$ spectrum,…

Recent observations of cosmic ray electrons from several instruments have revealed various degrees of deviation in the measured electron energy distribution from a simple power-law, in a form of an excess around TeV energies. An even more…

Astrophysics of Galaxies · Physics 2015-05-13 Lukasz Stawarz , Vahe Petrosian , Roger D. Blandford

We try to interpret the recently updated measurement of the cosmic ray electron (CRE) spectrum observed by Fermi-LAT, together with PAMELA data on positron fraction, in a single-component scenario adopting different propagation setups; we…

High Energy Astrophysical Phenomena · Physics 2022-03-02 Giuseppe Di Bernardo , Carmelo Evoli , Daniele Gaggero , Dario Grasso , Luca Maccione , Mario N. Mazziotta

The AMS-02 collaboration has just released its first result of the cosmic positron fraction $e^+/(e^-+e^+)$ with high precision up to $\sim 350$ GeV. The AMS-02 result shows the same trend with the previous PAMELA result, which requires…

High Energy Astrophysical Phenomena · Physics 2014-07-15 Qiang Yuan , Xiao-Jun Bi , Guo-Ming Chen , Yi-Qing Guo , Su-Jie Lin , Xinmin Zhang

We discuss the recently observed `excesses' in cosmic ray electron and positron fluxes which have been widely interpreted as signals of dark matter. By considering the production and acceleration of secondary electrons and positrons in…

High Energy Astrophysical Phenomena · Physics 2017-08-23 Philipp Mertsch , Subir Sarkar

We isolated the anomalous part of the cosmic electron-positron flux within a Bayesian likelihood analysis. Using 219 recent cosmic ray spectral data points, we inferred the values of selected cosmic ray propagation parameters. In the…

High Energy Astrophysical Phenomena · Physics 2012-04-25 Katie Auchettl , Csaba Balázs

We reveal that the energy spectra of electrons-positrons in primary cosmic rays measured at atmosphere top have double structures: an excess component $\Phi^s_{e^+}(E)=\Phi^s_{e^-}(E)$ around $400 GeV$, which origins from a strong…

High Energy Astrophysical Phenomena · Physics 2020-06-24 Wei Zhu , Pen Liu , Jianhong Ruan , Lei Feng , Fan Wang

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 , .

PAMELA's observation that the cosmic ray positron fraction increases rapidly with energy implies the presence of primary sources of energetic electron-positron pairs. Of particular interest is the possibility that dark matter annihilations…

High Energy Physics - Phenomenology · Physics 2014-11-20 Dan Hooper , Kathryn M. Zurek

We study the compatibility of Alpha Magnetic Spectrometer (AMS-02) data on the cosmic-ray (CR) positron fraction with data on the CR electron and positron spectra provided by PAMELA and Fermi LAT. We do that in terms of a novel propagation…

High Energy Astrophysical Phenomena · Physics 2013-11-19 Daniele Gaggero , Luca Maccione , Giuseppe Di Bernardo , Carmelo Evoli , Dario Grasso

The PAMELA collaboration recently released the $e^+$ absolute spectrum between 1 and 300 GeV in addition to the positron fraction and the $e^-$ spectrum previously measured in the same period. We use the newly developed three-dimensional…

High Energy Astrophysical Phenomena · Physics 2014-04-30 Daniele Gaggero , Dario Grasso , Luca Maccione , Giuseppe Di Bernardo , Carmelo Evoli

We present a numerical extension to the analytical propagation model introduced in Hein and Spanier (2008) to describe the leptonic population in the galactic disc. The model is used to derive a possible identification of the components…

High Energy Astrophysical Phenomena · Physics 2011-07-06 Alex Ivascenko , Felix Spanier

The Fermi-LAT experiment recently reported high precision measurements of the spectrum of cosmic-ray electrons-plus-positrons (CRE) between 20 GeV and 1 TeV. The spectrum shows no prominent spectral features, and is significantly harder…

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