title: Search for Cosmic-Ray Electron and Positron Anisotropies with Seven Years of Fermi Large Area Telescope Data.
abstract: The Large Area Telescope on board the Fermi Gamma-ray Space Telescope has collected the largest ever sample of high-energy cosmic-ray electron and positron events since the beginning of its operation. Potential anisotropies in the arrival directions of cosmic-ray electrons or positrons could be a signature of the presence of nearby sources. We use almost seven years of data with energies above 42 GeV processed with the Pass 8 reconstruction. The present data sample can probe dipole anisotropies down to a level of 10^{-3}. We take into account systematic effects that could mimic true anisotropies at this level. We present a detailed study of the event selection optimization of the cosmic-ray electrons and positrons to be used for anisotropy searches. Since no significant anisotropies have been detected on any angular scale, we present upper limits on the dipole anisotropy. The present constraints are among the strongest to date probing the presence of nearby young and middle-aged sources.
authors.affiliation: Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Abdollahi
authors.affiliation: Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Ackermann
authors.affiliation: Department of Physics and Astronomy, Clemson University, Kinard Lab of Physics, Clemson, South Carolina 29634-0978, USA.
authors.forename: M
authors.initials: M
authors.lastname: Ajello
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: A
authors.initials: A
authors.lastname: Albert
authors.affiliation: Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, California 95064, USA.
authors.forename: W B
authors.initials: WB
authors.lastname: Atwood
authors.affiliation: Dipartimento di Fisica "Enrico Fermi" dell'Università di Pisa, I-56126 Pisa, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Baldini
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste, Italy.|Dipartimento di Fisica, Università di Trieste, I-34127 Trieste, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Barbiellini
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Bellazzini
authors.affiliation: Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari, I-70126 Bari, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Bissaldi
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: E D
authors.initials: ED
authors.lastname: Bloom
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino, Italy.|Dipartimento di Fisica, Università degli Studi di Torino, I-10125 Torino, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Bonino
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: E
authors.initials: E
authors.lastname: Bottacini
authors.affiliation: NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Brandt
authors.affiliation: Laboratoire Leprince-Ringuet, École polytechnique, CNRS/IN2P3, F-91128 Palaiseau, France.
authors.forename: P
authors.initials: P
authors.lastname: Bruel
authors.affiliation: NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
authors.forename: S
authors.initials: S
authors.lastname: Buson
authors.affiliation: Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari, I-70126 Bari, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Caragiulo
authors.affiliation: Agenzia Spaziale Italiana (ASI) Science Data Center, I-00133 Roma, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Cavazzuti
authors.affiliation: College of Science, George Mason University, Fairfax, Virginia 22030, USA resident at Naval Research Laboratory, Washington, DC 20375, USA.
authors.forename: A
authors.initials: A
authors.lastname: Chekhtman
authors.affiliation: Agenzia Spaziale Italiana (ASI) Science Data Center, I-00133 Roma, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Ciprini
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Costanza
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino, Italy.|Institute for Theoretical Particle Physics and Cosmology, (TTK), RWTH Aachen University, D-52056 Aachen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Cuoco
authors.affiliation: Agenzia Spaziale Italiana (ASI) Science Data Center, I-00133 Roma, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Cutini
authors.affiliation: INAF Istituto di Radioastronomia, I-40129 Bologna, Italy.|Dipartimento di Astronomia, Università di Bologna, I-40127 Bologna, Italy.
authors.forename: F
authors.initials: F
authors.lastname: D'Ammando
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.|Università Telematica Pegaso, Piazza Trieste e Trento, 48, I-80132 Napoli, Italy.
authors.forename: F
authors.initials: F
authors.lastname: de Palma
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino, Italy.|Università di Udine, I-33100 Udine, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Desiante
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: S W
authors.initials: SW
authors.lastname: Digel
authors.affiliation: Dipartimento di Fisica "Enrico Fermi" dell'Università di Pisa, I-56126 Pisa, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Di Lalla
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: M
authors.initials: M
authors.lastname: Di Mauro
authors.affiliation: Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari, I-70126 Bari, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Di Venere
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Donaggio
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: P S
authors.initials: PS
authors.lastname: Drell
authors.affiliation: Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari, I-70126 Bari, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Favuzzi
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: W B
authors.initials: WB
authors.lastname: Focke
authors.affiliation: Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Fukazawa
authors.affiliation: Erlangen Centre for Astroparticle Physics, D-91058 Erlangen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Funk
authors.affiliation: Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari, I-70126 Bari, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Fusco
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Gargano
authors.affiliation: Agenzia Spaziale Italiana (ASI) Science Data Center, I-00133 Roma, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Gasparrini
authors.affiliation: Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari, I-70126 Bari, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Giglietto
authors.affiliation: Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari, I-70126 Bari, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Giordano
authors.affiliation: INAF Istituto di Radioastronomia, I-40129 Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Giroletti
authors.affiliation: NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.|Department of Physics and Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: D
authors.initials: D
authors.lastname: Green
authors.affiliation: NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
authors.forename: S
authors.initials: S
authors.lastname: Guiriec
authors.affiliation: NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
authors.forename: A K
authors.initials: AK
authors.lastname: Harding
authors.affiliation: Friedrich-Alexander-Universität, Erlangen-Nürnberg, Schlossplatz 4, 91054 Erlangen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Jogler
authors.affiliation: Science Institute, University of Iceland, IS-107 Reykjavik, Iceland.
authors.forename: G
authors.initials: G
authors.lastname: Jóhannesson
authors.affiliation: Department of Physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kamae
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Kuss
authors.affiliation: Department of Physics, KTH Royal Institute of Technology, AlbaNova, SE-106 91 Stockholm, Sweden.|The Oskar Klein Centre for Cosmoparticle Physics, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Larsson
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Latronico
authors.affiliation: Institute of Space Sciences (IEEC-CSIC), Campus UAB, E-08193 Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste, Italy.|Dipartimento di Fisica, Università di Trieste, I-34127 Trieste, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Longo
authors.affiliation: Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari, I-70126 Bari, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Loparco
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Lubrano
authors.affiliation: Department of Physics and Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Magill
authors.affiliation: Erlangen Centre for Astroparticle Physics, D-91058 Erlangen, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Malyshev
authors.affiliation: Dipartimento di Fisica "Enrico Fermi" dell'Università di Pisa, I-56126 Pisa, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Manfreda
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: M N
authors.initials: MN
authors.lastname: Mazziotta
authors.affiliation: Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: M
authors.initials: M
authors.lastname: Meehan
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: P F
authors.initials: PF
authors.lastname: Michelson
authors.affiliation: Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
authors.forename: W
authors.initials: W
authors.lastname: Mitthumsiri
authors.affiliation: Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Mizuno
authors.affiliation: Department of Physics and Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA.|Center for Research and Exploration in Space Science and Technology (CRESST) and NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Moiseev
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Monzani
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Roma "Tor Vergata", I-00133 Roma, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Morselli
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino, Italy.|Dipartimento di Fisica, Università degli Studi di Torino, I-10125 Torino, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Negro
authors.affiliation: Laboratoire Univers et Particules de Montpellier, Université Montpellier, CNRS/IN2P3, F-34095 Montpellier, France.
authors.forename: E
authors.initials: E
authors.lastname: Nuss
authors.affiliation: Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ohsugi
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: N
authors.initials: N
authors.lastname: Omodei
authors.affiliation: Max-Planck-Institut für Physik, D-80805 München, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Paneque
authors.affiliation: NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Perkins
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Pesce-Rollins
authors.affiliation: Laboratoire Univers et Particules de Montpellier, Université Montpellier, CNRS/IN2P3, F-34095 Montpellier, France.
authors.forename: F
authors.initials: F
authors.lastname: Piron
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Pivato
authors.affiliation: Erlangen Centre for Astroparticle Physics, D-91058 Erlangen, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Principe
authors.affiliation: Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari, I-70126 Bari, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Rainò
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova, Italy.|Dipartimento di Fisica e Astronomia "G. Galilei", Università di Padova, I-35131 Padova, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Rando
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Razzano
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.|Institut für Astro- und Teilchenphysik and Institut für Theoretische Physik, Leopold-Franzens-Universität Innsbruck, A-6020 Innsbruck, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Reimer
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.|Institut für Astro- und Teilchenphysik and Institut für Theoretische Physik, Leopold-Franzens-Universität Innsbruck, A-6020 Innsbruck, Austria.
authors.forename: O
authors.initials: O
authors.lastname: Reimer
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Sgrò
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Simone
authors.affiliation: NYCB Real-Time Computing Inc., Lattingtown, New York 11560-1025, USA.
authors.forename: E J
authors.initials: EJ
authors.lastname: Siskind
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Spada
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Spandre
authors.affiliation: Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari, I-70126 Bari, Italy.|Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Spinelli
authors.affiliation: Max-Planck Institut für extraterrestrische Physik, D-85748 Garching, Germany.
authors.forename: A W
authors.initials: AW
authors.lastname: Strong
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.|Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tajima
authors.affiliation: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Thayer
authors.affiliation: Institute of Space Sciences (IEEC-CSIC), Campus UAB, E-08193 Barcelona, Spain.|Institució Catalana de Recerca i Estudis Avançats (ICREA), E-08010 Barcelona, Spain.
authors.forename: D F
authors.initials: DF
authors.lastname: Torres
authors.affiliation: NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.|Department of Physics and Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: E
authors.initials: E
authors.lastname: Troja
authors.affiliation: Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: J
authors.initials: J
authors.lastname: Vandenbroucke
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, and Università di Trieste, I-34127 Trieste, Italy.|Laboratory for Astroparticle Physics, University of Nova Gorica, Vipavska 13, SI-5000 Nova Gorica, Slovenia.
authors.forename: G
authors.initials: G
authors.lastname: Zaharijas
authors.affiliation: Département de Physique Nucléaire et Corpuscolaire (DPNC), University of Geneva, CH-1211 Genéve 4, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Zimmer