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, Roman 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

137 Citations (Scopus)

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
Externally publishedYes

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, Roman; 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, Roman ; 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.
@article{6bc7ec7b2eb34e249c164a2a20179772,
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 Roman 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 = "6",
day = "1",
doi = "10.1088/0004-637X/698/2/2121",
language = "English (US)",
volume = "68",
pages = "2121--2130",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "2",

}

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, Roman

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

Y1 - 2009/6/1

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

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

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

VL - 68

SP - 2121

EP - 2130

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

ER -