Broad-line radio galaxies observed with fermi-lat

The origin of the GeV γ-ray emission

Jun Kataoka, Stawarz, Y. Takahashi, C. C. Cheung, M. Hayashida, P. Grandi, T. H. Burnett, A. Celotti, S. J. Fegan, P. Fortin, Keiichi Maeda, T. Nakamori, G. B. Taylor, G. Tosti, S. W. Digel, W. McConville, J. Finke, F. D'Ammando

    Research output: Contribution to journalArticle

    55 Citations (Scopus)

    Abstract

    We report on a detailed investigation of the γ-ray emission from 18 broad-line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed γ-ray emission reveals in addition possible flux variability in both sources. No statistically significant γ-ray detection of the other BLRGs was found, however, in the considered data set. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in γ-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the γ-ray flux variability and a number of other arguments presented, indicates that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high-accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found that none were detected in γ-rays. A simple phenomenological hybrid model applied for the broadband emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is ≥1% on average for BLRGs, whereas it is ≤0.1% for Seyfert 1 galaxies.

    Original languageEnglish
    Article number29
    JournalAstrophysical Journal
    Volume740
    Issue number1
    DOIs
    Publication statusPublished - 2011 Oct 10

    Fingerprint

    radio galaxies
    rays
    radio
    galaxies
    active galaxies
    indication
    telescopes
    broadband
    photons
    radiation
    accretion

    Keywords

    • galaxies: active
    • galaxies: individual (3C 120, 3C 111)
    • galaxies: jets
    • gamma rays: galaxies
    • radiation mechanisms: non-thermal
    • X-rays: galaxies

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Kataoka, J., Stawarz, Takahashi, Y., Cheung, C. C., Hayashida, M., Grandi, P., ... D'Ammando, F. (2011). Broad-line radio galaxies observed with fermi-lat: The origin of the GeV γ-ray emission. Astrophysical Journal, 740(1), [29]. https://doi.org/10.1088/0004-637X/740/1/29

    Broad-line radio galaxies observed with fermi-lat : The origin of the GeV γ-ray emission. / Kataoka, Jun; Stawarz; Takahashi, Y.; Cheung, C. C.; Hayashida, M.; Grandi, P.; Burnett, T. H.; Celotti, A.; Fegan, S. J.; Fortin, P.; Maeda, Keiichi; Nakamori, T.; Taylor, G. B.; Tosti, G.; Digel, S. W.; McConville, W.; Finke, J.; D'Ammando, F.

    In: Astrophysical Journal, Vol. 740, No. 1, 29, 10.10.2011.

    Research output: Contribution to journalArticle

    Kataoka, J, Stawarz, Takahashi, Y, Cheung, CC, Hayashida, M, Grandi, P, Burnett, TH, Celotti, A, Fegan, SJ, Fortin, P, Maeda, K, Nakamori, T, Taylor, GB, Tosti, G, Digel, SW, McConville, W, Finke, J & D'Ammando, F 2011, 'Broad-line radio galaxies observed with fermi-lat: The origin of the GeV γ-ray emission', Astrophysical Journal, vol. 740, no. 1, 29. https://doi.org/10.1088/0004-637X/740/1/29
    Kataoka, Jun ; Stawarz ; Takahashi, Y. ; Cheung, C. C. ; Hayashida, M. ; Grandi, P. ; Burnett, T. H. ; Celotti, A. ; Fegan, S. J. ; Fortin, P. ; Maeda, Keiichi ; Nakamori, T. ; Taylor, G. B. ; Tosti, G. ; Digel, S. W. ; McConville, W. ; Finke, J. ; D'Ammando, F. / Broad-line radio galaxies observed with fermi-lat : The origin of the GeV γ-ray emission. In: Astrophysical Journal. 2011 ; Vol. 740, No. 1.
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    abstract = "We report on a detailed investigation of the γ-ray emission from 18 broad-line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed γ-ray emission reveals in addition possible flux variability in both sources. No statistically significant γ-ray detection of the other BLRGs was found, however, in the considered data set. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in γ-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the γ-ray flux variability and a number of other arguments presented, indicates that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high-accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found that none were detected in γ-rays. A simple phenomenological hybrid model applied for the broadband emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is ≥1{\%} on average for BLRGs, whereas it is ≤0.1{\%} for Seyfert 1 galaxies.",
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    AU - Takahashi, Y.

    AU - Cheung, C. C.

    AU - Hayashida, M.

    AU - Grandi, P.

    AU - Burnett, T. H.

    AU - Celotti, A.

    AU - Fegan, S. J.

    AU - Fortin, P.

    AU - Maeda, Keiichi

    AU - Nakamori, T.

    AU - Taylor, G. B.

    AU - Tosti, G.

    AU - Digel, S. W.

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    AU - D'Ammando, F.

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