γ -Ray and parsec-scale jet properties of a complete sample of blazars from the mojave program

The MOJAVE Collaboration, The FERMI LAT Collaboration

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    78 Citations (Scopus)

    Abstract

    We investigate the Fermi Large Area Telescope γ -ray and 15 GHz Very Long Baseline Array radio properties of a joint γ -ray and radio-selected sample of active galactic nuclei (AGNs) obtained during the first 11 months of the Fermi mission (2008 August 4-2009 July 5). Our sample contains the brightest 173 AGNs in these bands above declination -30° during this period, and thus probes the full range of γ -ray loudness (γ -ray to radio band luminosity ratio) in the bright blazar population. The latter quantity spans at least 4 orders of magnitude, reflecting a wide range of spectral energy distribution (SED) parameters in the bright blazar population. The BL Lac objects, however, display a linear correlation of increasing γ -ray loudness with synchrotron SED peak frequency, suggesting a universal SED shape for objects of this class. The synchrotron self-Compton model is favored for the γ -ray emission in these BL Lac objects over external seed photon models, since the latter predict a dependence of Compton dominance on Doppler factor that would destroy any observed synchrotron SED-peak-γ -ray-loudness correlation. The high-synchrotron peaked (HSP) BL Lac objects are distinguished by lower than average radio core brightness temperatures, and none display large radio modulation indices or high linear core polarization levels. No equivalent trends are seen for the flat-spectrum radio quasars (FSRQs) in our sample. Given the association of such properties with relativistic beaming, we suggest that the HSP BL Lac objects have generally lower Doppler factors than the lower-synchrotron peaked BL Lac objects or FSRQs in our sample.

    Original languageEnglish
    Article number27
    JournalAstrophysical Journal
    Volume742
    Issue number1
    DOIs
    Publication statusPublished - 2011 Nov 20

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    Keywords

    • BL Lacertae objects: general
    • galaxies: active
    • galaxies: jets
    • gamma rays: galaxies
    • quasars: general
    • radio continuum: galaxies

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

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