Relativistic Jet Physics from MOJAVE

The Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments (MOJAVE) program present 1625 new 15 GHz VLBA images of 295 jets associated with active galactic nuclei (AGNs) from the MOJAVE and 2 cm VLBA surveys. For 274 AGNs with at least 5 VLBA epochs, the authors have analyzed the kinematics of 961 bright features in their parsec-scale jets. In the case of 451 jet features that had at least 10 epochs, they examined their kinematics for possible accelerations. At least half of the well-sampled features have non-radial and/or accelerating trajectories, indicating that non-ballistic motion is common in AGN jets. The distribution of maximum apparent jet speeds in all 295 AGNs measured by MOJAVE is peaked below 5c, with very few jets with apparent speeds >30c. The fastest speed is ~50c and is indicative of a maximum jet Lorentz factor of ~50 in the parent population. An envelope in the maximum jet speed versus redshift distribution of our sample provides additional evidence of this upper limit. The Fermi-Large Area Telescope (LAT)-detected ɣ-ray AGNs have, on average, higher jet speeds than non-LAT-detected AGNs, indicating a strong correlation between parsec-scale jet speed and the ɣ-ray Doppler boosting factor. Of the five gamma-ray loud narrow-lined Seyfert I AGNs in our sample, three show highly superluminal jet motions, while the others have sub-luminal speeds. This indicates that some narrow-lined Seyfert I AGNs possess powerful jets with Lorentz factors consistent with typical BL Lac objects and flat-spectrum radio quasars.

Image: An example of the 1625 naturally-weighted 15 GHz total intensity VLBA contour images of individual epoch observations in the MOJAVE AGN sample.

Science Team: M. L. Lister (Purdue), M. F. Aller (Michigan), H. D. Aller (Michigan), D. C. Homan (Denison), K. I. Kellermann (NRAO), Y. Y. Kovalev (Lebedev, València), A. B. Pushkarev (Lebedev, Crimean Astro. Obs.), J. L. Richards (Purdue), E. Ros (MPIfR, Velancia,), and T. Savolainen (MPIfR, Aalto).

Publication: MOJAVE: XIII. Parsec-scale AGN Jet Kinematics Analysis Based on 19 years of VLBA Observations at 15 GHz, 2016, Astronomical Journal, 152, 12.

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