The study of TeV variability and the duty cycle of Mrk 421 from 3 Yr of observations with the Milagro observatory

A. A. Abdo, A. U. Abeysekara, B. T. Allen, T. Aune, A. S. Barber, D. Berley, J. Braun, C. Chen, G. E. Christopher, R. S. Delay, T. Deyoung, B. L. Dingus, R. W. Ellsworth, N. Fraija, M. M. González, J. A. Goodman, E. Hays, C. M. Hoffman, P. H. Hüntemeyer, A. ImranB. E. Kolterman, J. T. Linnemann, A. Marinelli, J. E. McEnery, T. Morgan, A. I. Mincer, P. Nemethy, B. Patricelli, J. Pretz, J. M. Ryan, P. M. Saz Parkinson, M. Schneider, A. Shoup, G. Sinnis, A. J. Smith, V. Vasileiou, G. P. Walker, D. A. Williams, G. B. Yodh

    Research output: Contribution to journalArticle

    Abstract

    TeV-flaring activity with timescales as short as tens of minutes and an orphan TeV flare have been observed from the blazar Markarian 421 (Mrk 421). The TeV emission from Mrk 421 is believed to be produced by leptonic synchrotron self-Compton (SSC) emission. In this scenario, correlations between the X-ray and the TeV fluxes are expected, TeV orphan flares are hardly explained, and the activity (measured as duty cycle) of the source at TeV energies is expected to be equal to or less than that observed in X-rays if only SSC is considered. To estimate the TeV duty cycle of Mrk 421 and to establish limits on its variability at different timescales, we continuously observed Mrk 421 with the Milagro observatory. Mrk 421 was detected by Milagro with a statistical significance of 7.1 standard deviations between 2005 September 21 and 2008 March 15. The observed spectrum is consistent with previous observations by VERITAS. We estimate the duty cycle of Mrk 421 for energies above 1 TeV for different hypotheses of the baseline flux and for different flare selections and we compared our results with the X-ray duty cycle estimated by Resconi et al. The robustness of the results is discussed.

    Original languageEnglish (US)
    Article number110
    JournalAstrophysical Journal
    Volume782
    Issue number2
    DOIs
    StatePublished - Feb 20 2014

    Fingerprint

    orphan
    observatories
    observatory
    flares
    cycles
    timescale
    synchrotrons
    x rays
    energy
    estimates
    standard deviation
    flaring

    Keywords

    • BL Lacertae objects: individual (Markarian 421)
    • gamma rays: general

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Abdo, A. A., Abeysekara, A. U., Allen, B. T., Aune, T., Barber, A. S., Berley, D., ... Yodh, G. B. (2014). The study of TeV variability and the duty cycle of Mrk 421 from 3 Yr of observations with the Milagro observatory. Astrophysical Journal, 782(2), [110]. https://doi.org/10.1088/0004-637X/782/2/110

    The study of TeV variability and the duty cycle of Mrk 421 from 3 Yr of observations with the Milagro observatory. / Abdo, A. A.; Abeysekara, A. U.; Allen, B. T.; Aune, T.; Barber, A. S.; Berley, D.; Braun, J.; Chen, C.; Christopher, G. E.; Delay, R. S.; Deyoung, T.; Dingus, B. L.; Ellsworth, R. W.; Fraija, N.; González, M. M.; Goodman, J. A.; Hays, E.; Hoffman, C. M.; Hüntemeyer, P. H.; Imran, A.; Kolterman, B. E.; Linnemann, J. T.; Marinelli, A.; McEnery, J. E.; Morgan, T.; Mincer, A. I.; Nemethy, P.; Patricelli, B.; Pretz, J.; Ryan, J. M.; Saz Parkinson, P. M.; Schneider, M.; Shoup, A.; Sinnis, G.; Smith, A. J.; Vasileiou, V.; Walker, G. P.; Williams, D. A.; Yodh, G. B.

    In: Astrophysical Journal, Vol. 782, No. 2, 110, 20.02.2014.

    Research output: Contribution to journalArticle

    Abdo, AA, Abeysekara, AU, Allen, BT, Aune, T, Barber, AS, Berley, D, Braun, J, Chen, C, Christopher, GE, Delay, RS, Deyoung, T, Dingus, BL, Ellsworth, RW, Fraija, N, González, MM, Goodman, JA, Hays, E, Hoffman, CM, Hüntemeyer, PH, Imran, A, Kolterman, BE, Linnemann, JT, Marinelli, A, McEnery, JE, Morgan, T, Mincer, AI, Nemethy, P, Patricelli, B, Pretz, J, Ryan, JM, Saz Parkinson, PM, Schneider, M, Shoup, A, Sinnis, G, Smith, AJ, Vasileiou, V, Walker, GP, Williams, DA & Yodh, GB 2014, 'The study of TeV variability and the duty cycle of Mrk 421 from 3 Yr of observations with the Milagro observatory', Astrophysical Journal, vol. 782, no. 2, 110. https://doi.org/10.1088/0004-637X/782/2/110
    Abdo, A. A. ; Abeysekara, A. U. ; Allen, B. T. ; Aune, T. ; Barber, A. S. ; Berley, D. ; Braun, J. ; Chen, C. ; Christopher, G. E. ; Delay, R. S. ; Deyoung, T. ; Dingus, B. L. ; Ellsworth, R. W. ; Fraija, N. ; González, M. M. ; Goodman, J. A. ; Hays, E. ; Hoffman, C. M. ; Hüntemeyer, P. H. ; Imran, A. ; Kolterman, B. E. ; Linnemann, J. T. ; Marinelli, A. ; McEnery, J. E. ; Morgan, T. ; Mincer, A. I. ; Nemethy, P. ; Patricelli, B. ; Pretz, J. ; Ryan, J. M. ; Saz Parkinson, P. M. ; Schneider, M. ; Shoup, A. ; Sinnis, G. ; Smith, A. J. ; Vasileiou, V. ; Walker, G. P. ; Williams, D. A. ; Yodh, G. B. / The study of TeV variability and the duty cycle of Mrk 421 from 3 Yr of observations with the Milagro observatory. In: Astrophysical Journal. 2014 ; Vol. 782, No. 2.
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    AU - Aune, T.

    AU - Barber, A. S.

    AU - Berley, D.

    AU - Braun, J.

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    AU - Christopher, G. E.

    AU - Delay, R. S.

    AU - Deyoung, T.

    AU - Dingus, B. L.

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    AU - Fraija, N.

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    AU - Imran, A.

    AU - Kolterman, B. E.

    AU - Linnemann, J. T.

    AU - Marinelli, A.

    AU - McEnery, J. E.

    AU - Morgan, T.

    AU - Mincer, A. I.

    AU - Nemethy, P.

    AU - Patricelli, B.

    AU - Pretz, J.

    AU - Ryan, J. M.

    AU - Saz Parkinson, P. M.

    AU - Schneider, M.

    AU - Shoup, A.

    AU - Sinnis, G.

    AU - Smith, A. J.

    AU - Vasileiou, V.

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