Searches for large-scale anisotropy in the arrival directions of cosmic rays detected above energy of 1019 eV at the Pierre auger observatory and the telescope array

The Pierre Auger Collaboration, The Telescope Array Collaboration, G. Farrar

    Research output: Contribution to journalArticle

    Abstract

    Spherical harmonic moments are well-suited for capturing anisotropy at any scale in the flux of cosmic rays. An unambiguous measurement of the full set of spherical harmonic coefficients requires full-sky coverage. This can be achieved by combining data from observatories located in both the northern and southern hemispheres. To this end, a joint analysis using data recorded at the Telescope Array and the Pierre Auger Observatory above 1019 eV is presented in this work. The resulting multipolar expansion of the flux of cosmic rays allows us to perform a series of anisotropy searches, and in particular to report on the angular power spectrum of cosmic rays above 1019 eV. No significant deviation from isotropic expectations is found throughout the analyses performed. Upper limits on the amplitudes of the dipole and quadrupole moments are derived as a function of the direction in the sky, varying between 7% and 13% for the dipole and between 7% and 10% for a symmetric quadrupole.

    Original languageEnglish (US)
    Article number794
    JournalAstrophysical Journal
    Volume794
    Issue number2
    DOIs
    StatePublished - Oct 20 2014

    Fingerprint

    cosmic ray
    arrivals
    cosmic rays
    observatories
    anisotropy
    observatory
    spherical harmonics
    telescopes
    sky
    quadrupoles
    moments
    energy
    Southern Hemisphere
    Northern Hemisphere
    power spectra
    dipole moments
    dipoles
    deviation
    expansion
    coefficients

    Keywords

    • Astroparticle physics
    • Cosmic rays

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    Searches for large-scale anisotropy in the arrival directions of cosmic rays detected above energy of 1019 eV at the Pierre auger observatory and the telescope array. / The Pierre Auger Collaboration; The Telescope Array Collaboration; Farrar, G.

    In: Astrophysical Journal, Vol. 794, No. 2, 794, 20.10.2014.

    Research output: Contribution to journalArticle

    @article{f1ee8e15ad3343998497d5307c9f93c6,
    title = "Searches for large-scale anisotropy in the arrival directions of cosmic rays detected above energy of 1019 eV at the Pierre auger observatory and the telescope array",
    abstract = "Spherical harmonic moments are well-suited for capturing anisotropy at any scale in the flux of cosmic rays. An unambiguous measurement of the full set of spherical harmonic coefficients requires full-sky coverage. This can be achieved by combining data from observatories located in both the northern and southern hemispheres. To this end, a joint analysis using data recorded at the Telescope Array and the Pierre Auger Observatory above 1019 eV is presented in this work. The resulting multipolar expansion of the flux of cosmic rays allows us to perform a series of anisotropy searches, and in particular to report on the angular power spectrum of cosmic rays above 1019 eV. No significant deviation from isotropic expectations is found throughout the analyses performed. Upper limits on the amplitudes of the dipole and quadrupole moments are derived as a function of the direction in the sky, varying between 7{\%} and 13{\%} for the dipole and between 7{\%} and 10{\%} for a symmetric quadrupole.",
    keywords = "Astroparticle physics, Cosmic rays",
    author = "{The Pierre Auger Collaboration} and {The Telescope Array Collaboration} and A. Aab and P. Abreu and M. Aglietta and Ahn, {E. J.} and {Al Samarai}, I. and Albuquerque, {I. F M} and I. Allekotte and J. Allen and P. Allison and A. Almela and Castillo, {J. Alvarez} and J. Alvarez-Mu{\~n}iz and Batista, {R. Alves} and M. Ambrosio and A. Aminaei and L. Anchordoqui and S. Andringa and C. Aramo and F. Arqueros and H. Asorey and P. Assis and J. Aublin and M. Ave and M. Avenier and G. Avila and Badescu, {A. M.} and Barber, {K. B.} and J. B{\"a}uml and C. Baus and Beatty, {J. J.} and Becker, {K. H.} and Bellido, {J. A.} and C. Berat and Bertaina, {M. E.} and X. Bertou and Biermann, {P. L.} and P. Billoir and M. Blanco and C. Bleve and H. Bl{\"u}mer and M. Boh{\'a}čov{\'a} and D. Boncioli and C. Bonifazi and R. Bonino and N. Borodai and J. Brack and I. Brancus and G. Farrar and Brown, {W. C.} and Ingyin Zaw",
    year = "2014",
    month = "10",
    day = "20",
    doi = "10.1088/0004-637X/794/2/172",
    language = "English (US)",
    volume = "794",
    journal = "Astrophysical Journal",
    issn = "0004-637X",
    publisher = "IOP Publishing Ltd.",
    number = "2",

    }

    TY - JOUR

    T1 - Searches for large-scale anisotropy in the arrival directions of cosmic rays detected above energy of 1019 eV at the Pierre auger observatory and the telescope array

    AU - The Pierre Auger Collaboration

    AU - The Telescope Array Collaboration

    AU - Aab, A.

    AU - Abreu, P.

    AU - Aglietta, M.

    AU - Ahn, E. J.

    AU - Al Samarai, I.

    AU - Albuquerque, I. F M

    AU - Allekotte, I.

    AU - Allen, J.

    AU - Allison, P.

    AU - Almela, A.

    AU - Castillo, J. Alvarez

    AU - Alvarez-Muñiz, J.

    AU - Batista, R. Alves

    AU - Ambrosio, M.

    AU - Aminaei, A.

    AU - Anchordoqui, L.

    AU - Andringa, S.

    AU - Aramo, C.

    AU - Arqueros, F.

    AU - Asorey, H.

    AU - Assis, P.

    AU - Aublin, J.

    AU - Ave, M.

    AU - Avenier, M.

    AU - Avila, G.

    AU - Badescu, A. M.

    AU - Barber, K. B.

    AU - Bäuml, J.

    AU - Baus, C.

    AU - Beatty, J. J.

    AU - Becker, K. H.

    AU - Bellido, J. A.

    AU - Berat, C.

    AU - Bertaina, M. E.

    AU - Bertou, X.

    AU - Biermann, P. L.

    AU - Billoir, P.

    AU - Blanco, M.

    AU - Bleve, C.

    AU - Blümer, H.

    AU - Boháčová, M.

    AU - Boncioli, D.

    AU - Bonifazi, C.

    AU - Bonino, R.

    AU - Borodai, N.

    AU - Brack, J.

    AU - Brancus, I.

    AU - Farrar, G.

    AU - Brown, W. C.

    AU - Zaw, Ingyin

    PY - 2014/10/20

    Y1 - 2014/10/20

    N2 - Spherical harmonic moments are well-suited for capturing anisotropy at any scale in the flux of cosmic rays. An unambiguous measurement of the full set of spherical harmonic coefficients requires full-sky coverage. This can be achieved by combining data from observatories located in both the northern and southern hemispheres. To this end, a joint analysis using data recorded at the Telescope Array and the Pierre Auger Observatory above 1019 eV is presented in this work. The resulting multipolar expansion of the flux of cosmic rays allows us to perform a series of anisotropy searches, and in particular to report on the angular power spectrum of cosmic rays above 1019 eV. No significant deviation from isotropic expectations is found throughout the analyses performed. Upper limits on the amplitudes of the dipole and quadrupole moments are derived as a function of the direction in the sky, varying between 7% and 13% for the dipole and between 7% and 10% for a symmetric quadrupole.

    AB - Spherical harmonic moments are well-suited for capturing anisotropy at any scale in the flux of cosmic rays. An unambiguous measurement of the full set of spherical harmonic coefficients requires full-sky coverage. This can be achieved by combining data from observatories located in both the northern and southern hemispheres. To this end, a joint analysis using data recorded at the Telescope Array and the Pierre Auger Observatory above 1019 eV is presented in this work. The resulting multipolar expansion of the flux of cosmic rays allows us to perform a series of anisotropy searches, and in particular to report on the angular power spectrum of cosmic rays above 1019 eV. No significant deviation from isotropic expectations is found throughout the analyses performed. Upper limits on the amplitudes of the dipole and quadrupole moments are derived as a function of the direction in the sky, varying between 7% and 13% for the dipole and between 7% and 10% for a symmetric quadrupole.

    KW - Astroparticle physics

    KW - Cosmic rays

    UR - http://www.scopus.com/inward/record.url?scp=84984848431&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84984848431&partnerID=8YFLogxK

    U2 - 10.1088/0004-637X/794/2/172

    DO - 10.1088/0004-637X/794/2/172

    M3 - Article

    VL - 794

    JO - Astrophysical Journal

    JF - Astrophysical Journal

    SN - 0004-637X

    IS - 2

    M1 - 794

    ER -