%0 Journal Article
%T PSR J2021+4026 IN THE GAMMA CYGNI REGION: THE FIRST VARIABLE γ-RAY PULSAR SEEN BY THE Fermi LAT
%+ Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112))
%+ Institut de recherche en astrophysique et planétologie (IRAP)
%+ Laboratoire Leprince-Ringuet (LLR)
%+ Istituto Nazionale di Fisica Nucleare, sezione di Bari (INFN, sezione di Bari)
%+ IEEC-CSIC
%+ Laboratoire Univers et Particules de Montpellier (LUPM)
%+ FERMI
%A Allafort, A.
%A Baldini, Luca
%A Ballet, Jean
%A Barbiellini, Guido
%A Bastieri, D.
%A Bellazzini, R.
%A Bonamente, E.
%A Bottacini, E.
%A J. Brandt, T.
%A Bregeon, J.
%A Bruel, Pascal
%A Buehler, R.
%A A. Caliandro, G.
%A A. Cameron, R.
%A Caraveo, P. A.
%A Cecchi, C.
%A Chaves, R.C.G.
%A Chekhtman, A.
%A Chiaro, G.
%A Claus, R.
%A d'Ammando, F.
%A de Palma, F.
%A Di Venere, L.
%A S. Drell, P.
%A Favuzzi, C.
%A C. Ferrara, E.
%A Franckowiak, A.
%A Gargano, F.
%A Gasparrini, D.
%A Giglietto, N.
%A Giroletti, M.
%A Glanzman, T.
%A Godfrey, G.
%A Guiriec, S.
%A Hadasch, D.
%A K. Harding, A.
%A Hayashida, M.
%A Hayashi, K.
%A Hays, E.
%A Hewitt, J.
%A Horan, D.
%A Jogler, T.
%A Kerr, M.
%A Knödlseder, Jürgen
%A Lande, J.
%A Larsson, S.
%A Latronico, L.
%A Lemoine-Goumard, M.
%A Longo, F.
%A Loparco, F.
%A Lubrano, P.
%A Malyshev, D.
%A Marelli, M.
%A Mayer, M.
%A N. Mazziotta, M.
%A Mehault, J.
%A Mizuno, T.
%A E. Monzani, M.
%A Morselli, A.
%A Murgia, S.
%A Omodei, N.
%A Orienti, M.
%A Orlando, E.
%A Paneque, D.
%A Pesce-Rollins, M.
%A Pierbattista, M.
%A Piron, F.
%A Pivato, G.
%A Porter, T.A.
%A Rando, R.
%A Razzano, M.
%A Reposeur, T.
%A Sartori, A.
%A M. Saz Parkinson, P.
%A Sgro, C.
%A Spinelli, P.
%A W. Strong, A.
%A Takahashi, H.
%A B. Thayer, J.
%A J. Thompson, D.
%A Tibaldo, L.
%A Tinivella, M.
%A F. Torres, D.
%A Tosti, G.
%A Uchiyama, Y.
%A L. Usher, T.
%A Vandenbroucke, J.
%A Vasileiou, V.
%A Venter, C.
%A Vianello, G.
%A Vitale, V.
%A L. Winer, B.
%A S. Wood, K.
%< avec comité de lecture
%@ 2041-8205
%J The Astrophysical journal letters
%I Bristol : IOP Publishing
%V 777
%P L2
%8 2013
%D 2013
%Z 1308.0358
%R 10.1088/2041-8205/777/1/L2
%K gamma rays: stars
%K pulsars: individual (PSR J2021+4026)
%K stars: neutron
%Z Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]
%Z Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]Journal articles
%X Long-term monitoring of PSR J2021+4026 in the heart of the Cygnus region with the Fermi Large Area Telescope unveiled a sudden decrease in flux above 100 MeV over a timescale shorter than a week. The "jump" was near MJD 55850 (2011 October 16), with the flux decreasing from (8.33 ± 0.08) × 10-10 erg cm-2 s-1 to (6.86 ± 0.13) × 10-10 erg cm-2 s-1. Simultaneously, the frequency spindown rate increased from (7.8 ± 0.1) × 10-13 Hz s-1 to (8.1 ± 0.1) × 10-13 Hz s-1. Significant (>5σ) changes in the pulse profile and marginal (<3σ) changes in the emission spectrum occurred at the same time. There is also evidence for a small, steady flux increase over the 3 yr preceding MJD 55850. This is the first observation at γ-ray energies of mode changes and intermittent behavior, observed at radio wavelengths for other pulsars. We argue that the change in pulsed γ-ray emission is due to a change in emission beaming and we speculate that it is precipitated by a shift in the magnetic field structure, leading to a change of either effective magnetic inclination or effective current.
%G English
%L in2p3-00915598
%U https://hal.in2p3.fr/in2p3-00915598
%~ IN2P3
%~ CEA
%~ INSU
%~ METEO
%~ UNIV-PARIS7
%~ X
%~ UNIV-TLSE3
%~ CENBG
%~ LLR
%~ CNRS
%~ UNIV-MONTP2
%~ CNES
%~ OMP
%~ OMP-IRAP
%~ X-LLR
%~ X-DEP
%~ X-DEP-PHYS
%~ LUPM
%~ DSM-IRFU
%~ IRFU-AIM
%~ MIPS
%~ UNIV-MONTPELLIER
%~ CEA-DRF
%~ LUPM_EMA
%~ UNIV-PARIS
%~ UP-SCIENCES
%~ GS-PHYSIQUE
%~ UNIV-UT3
%~ UT3-INP
%~ UT3-TOULOUSEINP
%~ UM1-UM2