Inferred Cosmic-Ray Spectrum from Fermi Large Area Telescope gamma-Ray Observations of Earth's Limb

Ackermann M, Ajello M, Albert A, Allafort A, Baldini L, Barbiellini G, Bastieri D, Bechtol K, Bellazzini R, Blandford RD, Bloom ED, Bonamente E, Bottacini E, Bouvier A, Brandt TJ, Brigida M, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Cecchi C, Charles E, Chaves RCG, Chekhtman A, Chiang J, Chiaro G, Ciprini S, Claus R, Cohen-Tanugi J, Conrad J, Cutini S, Dalton M, D'Ammando F, de Angelis A, de Palma F, Dermer CD, Digel SW, Di Venere L, do Couto e Silva E, Drell PS, Drlica-Wagner A, Favuzzi C, Fegan SJ, Ferrara EC, Focke WB, Franckowiak A, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Germani S, Giglietto N, Giordano F, Giroletti M, Glanzman T, Godfrey G, Gomez-Vargas GA, Grenier IA, Grove JE, Guiriec S, Gustafsson M, Hadasch D, Hanabata Y, Harding AK, Hayashida M, Hayashi K, Hewitt JW, Horan D, Hou X, Hughes RE, Inoue Y, Jackson MS, Jogler T, Johannesson G, Johnson AS, Kamae T, Kawano T, Knoedlseder J, Kuss M, Lande J, Larsson S, Latronico L, Longo F, Loparco F, Lovellette MN, Lubrano P, Mayer M, Mazziotta MN, McEnery JE, Mehault J, Michelson PF, Mitthumsiri W, Mizuno T, Moiseev AA, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nemmen R, Nuss E, Ohsugi T, Okumura A, Orienti M, Orlando E, Ormes JF, Paneque D, Panetta JH, Perkins JS, Pesce-Rollins M, Piron F, Pivato G, Porter TA, Raino S, Rando R, Razzano M, Razzaque S, Reimer A, Reimer O, Ritz S, Roth M, Schaal M, Schulz A, Sgro C, Siskind EJ, Spandre G, Spinelli P, Strong AW, Takahashi H, Takeuchi Y, Thayer JG, Thayer JB, Thompson DJ, Tibaldo L, Tinivella M, Torres DF, Tosti G, Troja E, Tronconi V, Usher TL, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Werner M, Winer BL, Wood KS, Wood M, Yang Z (2014)

Publication Status: Published

Publication Type: Journal article

Publication year: 2014

Journal

Publisher: American Physical Society

Book Volume: 112

DOI: 10.1103/PhysRevLett.112.151103

Abstract

Recent accurate measurements of cosmic-ray (CR) species by ATIC-2, CREAM, and PAMELA reveal an unexpected hardening in the proton and He spectra above a few hundred GeV, a gradual softening of the spectra just below a few hundred GeV, and a harder spectrum of He compared to that of protons. These newly discovered features may offer a clue to the origin of high-energy CRs. We use the Fermi Large Area Telescope observations of the gamma-ray emission from Earth's limb for an indirect measurement of the local spectrum of CR protons in the energy range similar to 90 GeV-6 TeV (derived from a photon energy range 15 GeV-1 TeV). Our analysis shows that single power law and broken power law spectra fit the data equally well and yield a proton spectrum with index 2.68 +/- 0.04 and 2.61 +/- 0.08 above similar to 200 GeV, respectively.

Authors with CRIS profile

Involved external institutions

AlbaNova University Centre / Kungliga Tekniska Högskolan AlbaNova Universitetscentrum Sweden (SE) Politecnico di Bari Italy (IT) École Polytechnique - Université Paris-Saclay France (FR) Deutsches Elektronen-Synchrotron DESY Germany (DE) Stanford University United States (USA) (US) National Institute for Nuclear Physics / Istituto Nazionale di Fisica Nucleare (INFN) Italy (IT) National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) Italy (IT) University of Udine / Università degli Studi di Udine Italy (IT) U.S. Naval Research Laboratory United States (USA) (US) Italian Space Agency / Agenzia Spaziale Italiana (ASI) Italy (IT) Stockholm University / Stockholms universitet Sweden (SE) Fermi National Accelerator Laboratory (Fermilab) United States (USA) (US) Hiroshima University Japan (JP) Universidad Autónoma de Madrid (UAM) Spain (ES) University of Tokyo Japan (JP) Japan Aerospace eXploration Agency (JAXA) Japan (JP) Ohio State University United States (USA) (US) National Aeronautics and Space Administration (NASA) United States (USA) (US) Royal Institute of Technology / Kungliga Tekniska Högskolan (KTH) Sweden (SE) University of Iceland (UI) / Háskóli Íslands Iceland (IS) Université Fédérale de Toulouse Midi-Pyrénées France (FR) Mahidol University / มหาวิทยาลัยมหิดล Thailand (TH) Center for Research and Exploration in Space Science & Technology (CRESST) United States (USA) (US) Nagoya University / 名古屋大学 Japan (JP) University of Johannesburg South Africa (ZA) NYCB Real-Time Computing, Inc. United States (USA) (US) Max-Planck-Institut für extraterrestrische Physik (MPE) / Max Planck Institute for Extraterrestrial Physics Germany (DE) Waseda University / 早稲田大学 Japan (JP) Institut de Ciències de l'Espai (ICE) Spain (ES) Institució Catalana de Recerca i Estudis Avançats (ICREA) / Catalan Institution for Research and Advanced Studies Spain (ES) Università degli Studi di Roma 'Tor Vergata' Italy (IT) University of Padua / Universita degli Studi di Padova Italy (IT) University of Montpellier / Université Montpellier France (FR) University of California Santa Cruz United States (USA) (US) University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot France (FR) University of California, Berkeley United States (USA) (US) George Mason University United States (USA) (US)

How to cite

APA:

Ackermann, M., Ajello, M., Albert, A., Allafort, A., Baldini, L., Barbiellini, G.,... Yang, Z. (2014). Inferred Cosmic-Ray Spectrum from Fermi Large Area Telescope gamma-Ray Observations of Earth's Limb. Physical Review Letters, 112. https://dx.doi.org/10.1103/PhysRevLett.112.151103

MLA:

Ackermann, M., et al. "Inferred Cosmic-Ray Spectrum from Fermi Large Area Telescope gamma-Ray Observations of Earth's Limb." Physical Review Letters 112 (2014).

BibTeX: Download