Spectrum and morphology of the two brightest Milagro sources in the Cygnus region: MGRO J2019+37 and MGRO J2031+41

A. A. Abdo, U. Abeysekara, B. T. Allen, T. Aune, D. Berley, E. Bonamente, G. E. Christopher, T. Deyoung, B. L. Dingus, R. W. Ellsworth, J. G. Galbraith-Frew, M. M. Gonzalez, J. A. Goodman, C. M. Hoffman, P. H. Hüntemeyer, C. M. Hui, B. E. Kolterman, J. T. Linnemann, J. E. McEnery, A. I. MincerT. Morgan, P. Nemethy, J. Pretz, J. M. Ryan, P. M. Saz Parkinson, A. Shoup, G. Sinnis, A. J. Smith, V. Vasileiou, G. P. Walker, D. A. Williams, G. B. Yodh

    Research output: Contribution to journalArticle

    Abstract

    The Cygnus region is a very bright and complex portion of the TeV sky, host to unidentified sources and a diffuse excess with respect to conventional cosmic-ray propagation models. Two of the brightest TeV sources, MGRO J2019+37 and MGRO J2031+41, are analyzed using Milagro data with a new technique, and their emission is tested under two different spectral assumptions: a power law and a power law with an exponential cutoff. The new analysis technique is based on an energy estimator that uses the fraction of photomultiplier tubes in the observatory that detect the extensive air shower. The photon spectrum is measured in the range 1-100 TeV using the last three years of Milagro data (2005-2008), with the detector in its final configuration. An F-test indicates that MGRO J2019+37 is better fit by a power law with an exponential cutoff than by a simple power law. The best-fitting parameters for the power law with exponential cutoff model are a normalization at 10 TeV of 7+5 -2 × 10-10 s-1 m-2 TeV -1, a spectral index of 2.0+0.5 -1.0, and a cutoff energy of 29+50 -16 TeV. MGRO J2031+41 shows no evidence of a cutoff. The best-fitting parameters for a power law are a normalization of 2.1+0.6 -0.6 × 10-10 s-1 m-2 TeV-1 and a spectral index of 3.22 +0.23 -0.18. The overall flux is subject to a 30% systematic uncertainty. The systematic uncertainty on the power-law indices is 0.1. Both uncertainties have been verified with cosmic-ray data. A comparison with previous results from TeV J2032+4130, MGRO J2031+41, and MGRO J2019+37 is also presented.

    Original languageEnglish (US)
    Article number159
    JournalAstrophysical Journal
    Volume753
    Issue number2
    DOIs
    StatePublished - Jul 10 2012

    Fingerprint

    power law
    cut-off
    cosmic ray
    cosmic rays
    cosmic ray showers
    photomultiplier tubes
    estimators
    energy
    sky
    observatories
    observatory
    propagation
    detectors
    photons
    air
    configurations
    index
    parameter
    normalisation

    Keywords

    • acceleration of particles
    • astroparticle physics
    • gamma rays: general
    • open clusters and associations: individual (Cyg OB1, Cyg OB2)
    • pulsars: general

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Abdo, A. A., Abeysekara, U., Allen, B. T., Aune, T., Berley, D., Bonamente, E., ... Yodh, G. B. (2012). Spectrum and morphology of the two brightest Milagro sources in the Cygnus region: MGRO J2019+37 and MGRO J2031+41. Astrophysical Journal, 753(2), [159]. https://doi.org/10.1088/0004-637X/753/2/159

    Spectrum and morphology of the two brightest Milagro sources in the Cygnus region : MGRO J2019+37 and MGRO J2031+41. / Abdo, A. A.; Abeysekara, U.; Allen, B. T.; Aune, T.; Berley, D.; Bonamente, E.; Christopher, G. E.; Deyoung, T.; Dingus, B. L.; Ellsworth, R. W.; Galbraith-Frew, J. G.; Gonzalez, M. M.; Goodman, J. A.; Hoffman, C. M.; Hüntemeyer, P. H.; Hui, C. M.; Kolterman, B. E.; Linnemann, J. T.; McEnery, J. E.; Mincer, A. I.; Morgan, T.; Nemethy, P.; Pretz, J.; Ryan, J. M.; Saz Parkinson, P. M.; Shoup, A.; Sinnis, G.; Smith, A. J.; Vasileiou, V.; Walker, G. P.; Williams, D. A.; Yodh, G. B.

    In: Astrophysical Journal, Vol. 753, No. 2, 159, 10.07.2012.

    Research output: Contribution to journalArticle

    Abdo, AA, Abeysekara, U, Allen, BT, Aune, T, Berley, D, Bonamente, E, Christopher, GE, Deyoung, T, Dingus, BL, Ellsworth, RW, Galbraith-Frew, JG, Gonzalez, MM, Goodman, JA, Hoffman, CM, Hüntemeyer, PH, Hui, CM, Kolterman, BE, Linnemann, JT, McEnery, JE, Mincer, AI, Morgan, T, Nemethy, P, Pretz, J, Ryan, JM, Saz Parkinson, PM, Shoup, A, Sinnis, G, Smith, AJ, Vasileiou, V, Walker, GP, Williams, DA & Yodh, GB 2012, 'Spectrum and morphology of the two brightest Milagro sources in the Cygnus region: MGRO J2019+37 and MGRO J2031+41', Astrophysical Journal, vol. 753, no. 2, 159. https://doi.org/10.1088/0004-637X/753/2/159
    Abdo, A. A. ; Abeysekara, U. ; Allen, B. T. ; Aune, T. ; Berley, D. ; Bonamente, E. ; Christopher, G. E. ; Deyoung, T. ; Dingus, B. L. ; Ellsworth, R. W. ; Galbraith-Frew, J. G. ; Gonzalez, M. M. ; Goodman, J. A. ; Hoffman, C. M. ; Hüntemeyer, P. H. ; Hui, C. M. ; Kolterman, B. E. ; Linnemann, J. T. ; McEnery, J. E. ; Mincer, A. I. ; Morgan, T. ; Nemethy, P. ; Pretz, J. ; Ryan, J. M. ; Saz Parkinson, P. M. ; Shoup, A. ; Sinnis, G. ; Smith, A. J. ; Vasileiou, V. ; Walker, G. P. ; Williams, D. A. ; Yodh, G. B. / Spectrum and morphology of the two brightest Milagro sources in the Cygnus region : MGRO J2019+37 and MGRO J2031+41. In: Astrophysical Journal. 2012 ; Vol. 753, No. 2.
    @article{70edb4d1dfb7414db6acf29679ca0476,
    title = "Spectrum and morphology of the two brightest Milagro sources in the Cygnus region: MGRO J2019+37 and MGRO J2031+41",
    abstract = "The Cygnus region is a very bright and complex portion of the TeV sky, host to unidentified sources and a diffuse excess with respect to conventional cosmic-ray propagation models. Two of the brightest TeV sources, MGRO J2019+37 and MGRO J2031+41, are analyzed using Milagro data with a new technique, and their emission is tested under two different spectral assumptions: a power law and a power law with an exponential cutoff. The new analysis technique is based on an energy estimator that uses the fraction of photomultiplier tubes in the observatory that detect the extensive air shower. The photon spectrum is measured in the range 1-100 TeV using the last three years of Milagro data (2005-2008), with the detector in its final configuration. An F-test indicates that MGRO J2019+37 is better fit by a power law with an exponential cutoff than by a simple power law. The best-fitting parameters for the power law with exponential cutoff model are a normalization at 10 TeV of 7+5 -2 × 10-10 s-1 m-2 TeV -1, a spectral index of 2.0+0.5 -1.0, and a cutoff energy of 29+50 -16 TeV. MGRO J2031+41 shows no evidence of a cutoff. The best-fitting parameters for a power law are a normalization of 2.1+0.6 -0.6 × 10-10 s-1 m-2 TeV-1 and a spectral index of 3.22 +0.23 -0.18. The overall flux is subject to a 30{\%} systematic uncertainty. The systematic uncertainty on the power-law indices is 0.1. Both uncertainties have been verified with cosmic-ray data. A comparison with previous results from TeV J2032+4130, MGRO J2031+41, and MGRO J2019+37 is also presented.",
    keywords = "acceleration of particles, astroparticle physics, gamma rays: general, open clusters and associations: individual (Cyg OB1, Cyg OB2), pulsars: general",
    author = "Abdo, {A. A.} and U. Abeysekara and Allen, {B. T.} and T. Aune and D. Berley and E. Bonamente and Christopher, {G. E.} and T. Deyoung and Dingus, {B. L.} and Ellsworth, {R. W.} and Galbraith-Frew, {J. G.} and Gonzalez, {M. M.} and Goodman, {J. A.} and Hoffman, {C. M.} and H{\"u}ntemeyer, {P. H.} and Hui, {C. M.} and Kolterman, {B. E.} and Linnemann, {J. T.} and McEnery, {J. E.} and Mincer, {A. I.} and T. Morgan and P. Nemethy and J. Pretz and Ryan, {J. M.} and {Saz Parkinson}, {P. M.} and A. Shoup and G. Sinnis and Smith, {A. J.} and V. Vasileiou and Walker, {G. P.} and Williams, {D. A.} and Yodh, {G. B.}",
    year = "2012",
    month = "7",
    day = "10",
    doi = "10.1088/0004-637X/753/2/159",
    language = "English (US)",
    volume = "753",
    journal = "Astrophysical Journal",
    issn = "0004-637X",
    publisher = "IOP Publishing Ltd.",
    number = "2",

    }

    TY - JOUR

    T1 - Spectrum and morphology of the two brightest Milagro sources in the Cygnus region

    T2 - MGRO J2019+37 and MGRO J2031+41

    AU - Abdo, A. A.

    AU - Abeysekara, U.

    AU - Allen, B. T.

    AU - Aune, T.

    AU - Berley, D.

    AU - Bonamente, E.

    AU - Christopher, G. E.

    AU - Deyoung, T.

    AU - Dingus, B. L.

    AU - Ellsworth, R. W.

    AU - Galbraith-Frew, J. G.

    AU - Gonzalez, M. M.

    AU - Goodman, J. A.

    AU - Hoffman, C. M.

    AU - Hüntemeyer, P. H.

    AU - Hui, C. M.

    AU - Kolterman, B. E.

    AU - Linnemann, J. T.

    AU - McEnery, J. E.

    AU - Mincer, A. I.

    AU - Morgan, T.

    AU - Nemethy, P.

    AU - Pretz, J.

    AU - Ryan, J. M.

    AU - Saz Parkinson, P. M.

    AU - Shoup, A.

    AU - Sinnis, G.

    AU - Smith, A. J.

    AU - Vasileiou, V.

    AU - Walker, G. P.

    AU - Williams, D. A.

    AU - Yodh, G. B.

    PY - 2012/7/10

    Y1 - 2012/7/10

    N2 - The Cygnus region is a very bright and complex portion of the TeV sky, host to unidentified sources and a diffuse excess with respect to conventional cosmic-ray propagation models. Two of the brightest TeV sources, MGRO J2019+37 and MGRO J2031+41, are analyzed using Milagro data with a new technique, and their emission is tested under two different spectral assumptions: a power law and a power law with an exponential cutoff. The new analysis technique is based on an energy estimator that uses the fraction of photomultiplier tubes in the observatory that detect the extensive air shower. The photon spectrum is measured in the range 1-100 TeV using the last three years of Milagro data (2005-2008), with the detector in its final configuration. An F-test indicates that MGRO J2019+37 is better fit by a power law with an exponential cutoff than by a simple power law. The best-fitting parameters for the power law with exponential cutoff model are a normalization at 10 TeV of 7+5 -2 × 10-10 s-1 m-2 TeV -1, a spectral index of 2.0+0.5 -1.0, and a cutoff energy of 29+50 -16 TeV. MGRO J2031+41 shows no evidence of a cutoff. The best-fitting parameters for a power law are a normalization of 2.1+0.6 -0.6 × 10-10 s-1 m-2 TeV-1 and a spectral index of 3.22 +0.23 -0.18. The overall flux is subject to a 30% systematic uncertainty. The systematic uncertainty on the power-law indices is 0.1. Both uncertainties have been verified with cosmic-ray data. A comparison with previous results from TeV J2032+4130, MGRO J2031+41, and MGRO J2019+37 is also presented.

    AB - The Cygnus region is a very bright and complex portion of the TeV sky, host to unidentified sources and a diffuse excess with respect to conventional cosmic-ray propagation models. Two of the brightest TeV sources, MGRO J2019+37 and MGRO J2031+41, are analyzed using Milagro data with a new technique, and their emission is tested under two different spectral assumptions: a power law and a power law with an exponential cutoff. The new analysis technique is based on an energy estimator that uses the fraction of photomultiplier tubes in the observatory that detect the extensive air shower. The photon spectrum is measured in the range 1-100 TeV using the last three years of Milagro data (2005-2008), with the detector in its final configuration. An F-test indicates that MGRO J2019+37 is better fit by a power law with an exponential cutoff than by a simple power law. The best-fitting parameters for the power law with exponential cutoff model are a normalization at 10 TeV of 7+5 -2 × 10-10 s-1 m-2 TeV -1, a spectral index of 2.0+0.5 -1.0, and a cutoff energy of 29+50 -16 TeV. MGRO J2031+41 shows no evidence of a cutoff. The best-fitting parameters for a power law are a normalization of 2.1+0.6 -0.6 × 10-10 s-1 m-2 TeV-1 and a spectral index of 3.22 +0.23 -0.18. The overall flux is subject to a 30% systematic uncertainty. The systematic uncertainty on the power-law indices is 0.1. Both uncertainties have been verified with cosmic-ray data. A comparison with previous results from TeV J2032+4130, MGRO J2031+41, and MGRO J2019+37 is also presented.

    KW - acceleration of particles

    KW - astroparticle physics

    KW - gamma rays: general

    KW - open clusters and associations: individual (Cyg OB1, Cyg OB2)

    KW - pulsars: general

    UR - http://www.scopus.com/inward/record.url?scp=84862886706&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84862886706&partnerID=8YFLogxK

    U2 - 10.1088/0004-637X/753/2/159

    DO - 10.1088/0004-637X/753/2/159

    M3 - Article

    VL - 753

    JO - Astrophysical Journal

    JF - Astrophysical Journal

    SN - 0004-637X

    IS - 2

    M1 - 159

    ER -