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. Mincer; P. 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

doi:10.1088/0004-637X/698/2/2121

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

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172 Scopus citations

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 language	English (US)
Pages (from-to)	2121-2130
Number of pages	10
Journal	Astrophysical Journal
Volume	68
Issue number	2
DOIs	https://doi.org/10.1088/0004-637X/698/2/2121
State	Published - Jun 2009
Externally published	Yes

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

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10.1088/0004-637X/698/2/2121

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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., ... 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

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

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title = "The large-scale cosmic-ray anisotropy as observed with milagro",

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.",

keywords = "Cosmic rays, Galaxy: halo, ISM: magnetic fields, Solar neighborhood, Sun: activity, Supernova remnants",

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

year = "2009",

month = jun,

doi = "10.1088/0004-637X/698/2/2121",

language = "English (US)",

volume = "68",

pages = "2121--2130",

journal = "Astrophysical Journal",

issn = "0004-637X",

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TY - JOUR

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

Y1 - 2009/6

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.

AB - 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.

KW - Cosmic rays

KW - Galaxy: halo

KW - ISM: magnetic fields

KW - Solar neighborhood

KW - Sun: activity

KW - Supernova remnants

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UR - http://www.scopus.com/inward/citedby.url?scp=85017594625&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/698/2/2121

DO - 10.1088/0004-637X/698/2/2121

M3 - Article

AN - SCOPUS:85017594625

SN - 0004-637X

VL - 68

SP - 2121

EP - 2130

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

ER -

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

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Keywords

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