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Published March 20, 2019 | Published + Accepted Version
Journal Article Open

MOJAVE. XVII. Jet Kinematics and Parent Population Properties of Relativistically Beamed Radio-loud Blazars


We present results from a parsec-scale jet kinematics study of 409 bright radio-loud active galactic nuclei (AGNs) based on 15 GHz Very Long Baseline Array (VLBA) data obtained between 1994 August 31 and 2016 December 26 as part of the 2 cm VLBA survey and Monitoring Of Jets in Active galactic nuclei with VLBA Experiments (MOJAVE) programs. We tracked 1744 individual bright features in 382 jets over at least 5 epochs. A majority (59%) of the best-sampled jet features showed evidence of accelerated motion at the >3σ level. Although most features within a jet typically have speeds within ~40% of a characteristic median value, we identified 55 features in 42 jets that had unusually slow pattern speeds, nearly all of which lie within 4 pc (100 pc deprojected) of the core feature. Our results, combined with other speeds from the literature, indicate a strong correlation between apparent jet speed and synchrotron peak frequency, with the highest jet speeds being found only in low-peaked AGNs. Using Monte Carlo simulations, we find best-fit parent population parameters for a complete sample of 174 quasars above 1.5 Jy at 15 GHz. Acceptable fits are found with a jet population that has a simple unbeamed power-law luminosity function incorporating pure luminosity evolution and a power-law Lorentz factor distribution ranging from 1.25 to 50 with slope −1.4 ± 0.2. The parent jets of the brightest radio quasars have a space density of 261 ± 19 Gpc^(−3) and unbeamed 15 GHz luminosities above ~10^(24.5) W Hz^(−1), consistent with FR II class radio galaxies.

Additional Information

© 2019 The American Astronomical Society. Received 2019 January 20; revised 2019 February 16; accepted 2019 February 18; published 2019 March 20. The MOJAVE project was supported by NASA-Fermi grants Nos. NNX08AV67G, NNX12A087G, and NNX15AU76G. Y.Y.K. and A.B.P. were supported by the Basic Research Program P-28 of the Presidium of the Russian Academy of Sciences and the government of the Russian Federation (agreement 05.Y09.21.0018). T.S. was supported by the Academy of Finland projects Nos. 274477, 284495, and 312496. T.H. was supported by the Academy of Finland project 317383. The Very Long Baseline Array and the National Radio Astronomy Observatory are facilities of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This research has used observations with RATAN-600 of the Special Astrophysical Observatory of the Russian Academy of Sciences. This work made use of the Swinburne University of Technology software correlator (Deller et al. 2011), developed as part of the Australian Major National Research Facilities Programme and operated under licence. This research has made use of data from the OVRO 40 m monitoring program Richards et al. (2011), which is supported in part by NASA grants Nos. NNX08AW31G, NNX11A043G, and NNX14AQ89G and NSF grants Nos. AST-0808050 and AST-1109911. This research has made use of data from the University of Michigan Radio Astronomy Observatory which has been supported by the University of Michigan and by a series of grants from the National Science Foundation, most recently No. AST-0607523. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

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Published - Lister_2019_ApJ_874_43.pdf

Accepted Version - 1902.09591.pdf


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August 19, 2023
October 20, 2023