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Relativistic bulk motion in active galactic nuclei
Abstract
We discuss the evidence for relativistic bulk motion of the emitting plasma in the nuclei of ~100 radio sources, which include BL Lacertae objects, radio quasars, and radio galaxies, with published VBLI measurements of the core angular dimension and radio flux. Comparing the predicted and observed high-frequency (X-ray) flux, in the framework of the synchrotron self-Compton model, we derive the beaming or Doppler factor for all sources. This is compared with other beaming indicators, such as the value of the expansion velocity (mostly superluminal and available for ~40% of the objects) and the ratio of the core to the extended radio flux (available for all but two sources). We find that the different beaming indicators agree reasonably well, supporting the simple kinematic model of ballistic motion of knots in a jet. Furthermore, the mean values of the bulk Lorentz factor and the angle to the line of sight derived for the superluminal sources are consistent with those found from the attempts to unify BL Lacertae objects and radio-loud quasars with Fanaroff-Riley Types I and II radio galaxies, respectively.
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Citations
Cited by
McKinney, J. C. (2006) · Monthly Notices of the Royal Astronomical Society · doi:10.1111/j.1365-2966.2006.10256.x · Cited by 599
Falcke, H. D., Körding, E. G., & Markoff, S. (2003) · arXiv (Cornell University) · doi:10.48550/arxiv.astro-ph/0305335 · Cited by 441
Kellermann, K. I., Lister, M. L., Homan, D. C., Vermeulen, R. C., Cohen, M. H., Ros, E., Kadler, M., Zensus, J. A., & Kovalev, Y. Y. (2004) · The Astrophysical Journal · doi:10.1086/421289 · Cited by 419
Morphology and Dynamics of Relativistic Jets
Marti, J. M., Muller, E., Font, J. A., Ibanez, J. M., & Marquina, A. (1997) · The Astrophysical Journal · doi:10.1086/303842 · Cited by 294
Giustini, M., & Proga, D. (2019) · Astronomy & Astrophysics · doi:10.1051/0004-6361/201833810 · Cited by 166
“…accretion and the ejection flows are almost isotropic, that is, the inclination angle of the observer’s l.o.s. is generally unimportant, except for the polar region, where the relativistic jet emission is observed being boosted when observed parallel to the l.o.s. (e.g., Ghisellini et al. 1993).”
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Metadata
- Authors
- Ghisellini, G., Padovani, P., Celotti, A., & Maraschi, L.
- Venue
- The Astrophysical Journal
- Publisher
- American Astronomical Society
- Published
- 1993-04
- Volume
- 407
- Pages
- 65
- ISSN
- 0004-637X (ISSN-L)
- 1538-4357
- OpenAlex
- W2075179680
- Cited by
- 544
- References
- 0
- FWCI
- 19.17
- Type
- journal article
- Language
- en
- Open access
- closed
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- Ghisellini, G., Padovani, P., Celotti, A., & Maraschi, L. (1993). Relativistic bulk motion in active galactic nuclei. The Astrophysical Journal. https://doi.org/10.1086/172493
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Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).
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