The large-scale cosmic-ray anisotropy as observed with milagro

A. A. Abdo, B. T. Allen, T. Aune, D. Berley, S. Casanova, C. Chen, B. L. Dingus, R. W. Ellsworth, L. Fleysher, R. Fleysher, M. M. Gonzalez, J. A. Goodman, C. M. Hoffman, B. Hopper, P. H. Hüntemeyer, B. E. Kolterman, C. P. Lansdell, J. T. Linnemann, J. E. McEnery, A. I. MincerP. Nemethy, D. Noyes, J. Pretz, J. M. Ryan, P. M. Saz Parkinson, A. Shoup, G. Sinnis, A. J. Smith, G. W. Sullivan, V. Vasileiou, G. P. Walker, D. A. Williams, G. B. Yodh

    Research output: Contribution to journalArticle

    Abstract

    Results are presented of a harmonic analysis of the large-scale cosmic-ray (CR) anisotropy as observed by the Milagro observatory. We show a two-dimensional display of the sidereal anisotropy projections in right ascension (R.A.) generated by the fitting of three harmonics to 18 separate declination bands. The Milagro observatory is a water Cherenkov detector located in the Jemez mountains near Los Alamos, New Mexico. With a high duty cycle and large field of view, Milagro is an excellent instrument for measuring this anisotropy with high sensitivity at TeV energies. The analysis is conducted using a seven-year data sample consisting of more than 95 billion events, the largest such data set in existence. We observe an anisotropy with a magnitude around 0.1% for CRs with a median energy of 6 TeV. The dominant feature is a deficit region of depth (2.49 ± 0.02 stat. ± 0.09 sys.) ×10-3 in the direction of the Galactic north pole centered at 189 deg R.A. We observe a steady increase in the magnitude of the signal over seven years.

    Original languageEnglish (US)
    Pages (from-to)2121-2130
    Number of pages10
    JournalAstrophysical Journal
    Volume68
    Issue number2
    DOIs
    StatePublished - Jun 1 2009

    Fingerprint

    cosmic ray
    cosmic rays
    anisotropy
    observatories
    observatory
    harmonic analysis
    declination
    field of view
    mountains
    energy
    poles
    projection
    harmonics
    cycles
    mountain
    sensitivity
    detectors
    water

    Keywords

    • Cosmic rays
    • Galaxy: halo
    • ISM: magnetic fields
    • Solar neighborhood
    • Sun: activity
    • Supernova remnants

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    Abdo, A. A., Allen, B. T., Aune, T., Berley, D., Casanova, S., Chen, C., ... Yodh, G. B. (2009). The large-scale cosmic-ray anisotropy as observed with milagro. Astrophysical Journal, 68(2), 2121-2130. https://doi.org/10.1088/0004-637X/698/2/2121

    The large-scale cosmic-ray anisotropy as observed with milagro. / Abdo, A. A.; Allen, B. T.; Aune, T.; Berley, D.; Casanova, S.; Chen, C.; Dingus, B. L.; Ellsworth, R. W.; Fleysher, L.; Fleysher, R.; Gonzalez, M. M.; Goodman, J. A.; Hoffman, C. M.; Hopper, B.; Hüntemeyer, P. H.; Kolterman, B. E.; Lansdell, C. P.; Linnemann, J. T.; McEnery, J. E.; Mincer, A. I.; Nemethy, P.; Noyes, D.; Pretz, J.; Ryan, J. M.; Saz Parkinson, P. M.; Shoup, A.; Sinnis, G.; Smith, A. J.; Sullivan, G. W.; Vasileiou, V.; Walker, G. P.; Williams, D. A.; Yodh, G. B.

    In: Astrophysical Journal, Vol. 68, No. 2, 01.06.2009, p. 2121-2130.

    Research output: Contribution to journalArticle

    Abdo, AA, Allen, BT, Aune, T, Berley, D, Casanova, S, Chen, C, Dingus, BL, Ellsworth, RW, Fleysher, L, Fleysher, R, Gonzalez, MM, Goodman, JA, Hoffman, CM, Hopper, B, Hüntemeyer, PH, Kolterman, BE, Lansdell, CP, Linnemann, JT, McEnery, JE, Mincer, AI, Nemethy, P, Noyes, D, Pretz, J, Ryan, JM, Saz Parkinson, PM, Shoup, A, Sinnis, G, Smith, AJ, Sullivan, GW, Vasileiou, V, Walker, GP, Williams, DA & Yodh, GB 2009, 'The large-scale cosmic-ray anisotropy as observed with milagro', Astrophysical Journal, vol. 68, no. 2, pp. 2121-2130. https://doi.org/10.1088/0004-637X/698/2/2121
    Abdo AA, Allen BT, Aune T, Berley D, Casanova S, Chen C et al. The large-scale cosmic-ray anisotropy as observed with milagro. Astrophysical Journal. 2009 Jun 1;68(2):2121-2130. https://doi.org/10.1088/0004-637X/698/2/2121
    Abdo, A. A. ; Allen, B. T. ; Aune, T. ; Berley, D. ; Casanova, S. ; Chen, C. ; Dingus, B. L. ; Ellsworth, R. W. ; Fleysher, L. ; Fleysher, R. ; Gonzalez, M. M. ; Goodman, J. A. ; Hoffman, C. M. ; Hopper, B. ; Hüntemeyer, P. H. ; Kolterman, B. E. ; Lansdell, C. P. ; Linnemann, J. T. ; McEnery, J. E. ; Mincer, A. I. ; Nemethy, P. ; Noyes, D. ; Pretz, J. ; Ryan, J. M. ; Saz Parkinson, P. M. ; Shoup, A. ; Sinnis, G. ; Smith, A. J. ; Sullivan, G. W. ; Vasileiou, V. ; Walker, G. P. ; Williams, D. A. ; Yodh, G. B. / The large-scale cosmic-ray anisotropy as observed with milagro. In: Astrophysical Journal. 2009 ; Vol. 68, No. 2. pp. 2121-2130.
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    abstract = "Results are presented of a harmonic analysis of the large-scale cosmic-ray (CR) anisotropy as observed by the Milagro observatory. We show a two-dimensional display of the sidereal anisotropy projections in right ascension (R.A.) generated by the fitting of three harmonics to 18 separate declination bands. The Milagro observatory is a water Cherenkov detector located in the Jemez mountains near Los Alamos, New Mexico. With a high duty cycle and large field of view, Milagro is an excellent instrument for measuring this anisotropy with high sensitivity at TeV energies. The analysis is conducted using a seven-year data sample consisting of more than 95 billion events, the largest such data set in existence. We observe an anisotropy with a magnitude around 0.1{\%} for CRs with a median energy of 6 TeV. The dominant feature is a deficit region of depth (2.49 ± 0.02 stat. ± 0.09 sys.) ×10-3 in the direction of the Galactic north pole centered at 189 deg R.A. We observe a steady increase in the magnitude of the signal over seven years.",
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    T1 - The large-scale cosmic-ray anisotropy as observed with milagro

    AU - Abdo, A. A.

    AU - Allen, B. T.

    AU - Aune, T.

    AU - Berley, D.

    AU - Casanova, S.

    AU - Chen, C.

    AU - Dingus, B. L.

    AU - Ellsworth, R. W.

    AU - Fleysher, L.

    AU - Fleysher, R.

    AU - Gonzalez, M. M.

    AU - Goodman, J. A.

    AU - Hoffman, C. M.

    AU - Hopper, B.

    AU - Hüntemeyer, P. H.

    AU - Kolterman, B. E.

    AU - Lansdell, C. P.

    AU - Linnemann, J. T.

    AU - McEnery, J. E.

    AU - Mincer, A. I.

    AU - Nemethy, P.

    AU - Noyes, D.

    AU - Pretz, J.

    AU - Ryan, J. M.

    AU - Saz Parkinson, P. M.

    AU - Shoup, A.

    AU - Sinnis, G.

    AU - Smith, A. J.

    AU - Sullivan, G. W.

    AU - Vasileiou, V.

    AU - Walker, G. P.

    AU - Williams, D. A.

    AU - Yodh, G. B.

    PY - 2009/6/1

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    N2 - Results are presented of a harmonic analysis of the large-scale cosmic-ray (CR) anisotropy as observed by the Milagro observatory. We show a two-dimensional display of the sidereal anisotropy projections in right ascension (R.A.) generated by the fitting of three harmonics to 18 separate declination bands. The Milagro observatory is a water Cherenkov detector located in the Jemez mountains near Los Alamos, New Mexico. With a high duty cycle and large field of view, Milagro is an excellent instrument for measuring this anisotropy with high sensitivity at TeV energies. The analysis is conducted using a seven-year data sample consisting of more than 95 billion events, the largest such data set in existence. We observe an anisotropy with a magnitude around 0.1% for CRs with a median energy of 6 TeV. The dominant feature is a deficit region of depth (2.49 ± 0.02 stat. ± 0.09 sys.) ×10-3 in the direction of the Galactic north pole centered at 189 deg R.A. We observe a steady increase in the magnitude of the signal over seven years.

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    KW - ISM: magnetic fields

    KW - Solar neighborhood

    KW - Sun: activity

    KW - Supernova remnants

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