There appears to be a fundamental problem facing Active Galactic Nuclei (AGN) jet models that require highly relativistic ejection speeds and small jet viewing angles to explain the large apparent superluminal motions seen in so many of the radio-loud quasars with high redshift. When the data are looked at closely it is found that, assuming the core component is unboosted, only a small percentage of the observed radio frequency flux density from these sources can be Doppler boosted. If the core component is boosted the percentage of boosted to unboosted flux will be higher but will still be far from the 90 percent required for Doppler boosting to have played a significant role. Without a highly directed, Doppler boosted component that dominates the observed flux, radio sources found in low-frequency finding surveys cannot be preferentially selected with small jet viewing angles. The distribution of jet orientations will then follow the sini curve associated with a random distribution, where only a very few sources (~1%) will have the small viewing angles (<8°) required to explain apparent superluminal motions vapp > 10c, and this makes it difficult to explain how around 33% of the radio-loud AGNs with high redshift can exhibit such highly superluminal motions. When the boosted component is the dominant one it can be argued that in a flux limited sample only those members with small viewing angles would be picked up while those with larger viewing angles (the un-boosted ones) would be missed. However, this is not the case when the boosted component is small and a new model to explain the high apparent superluminal motions may be needed if the redshifts of high-redshift quasars are to remain entirely cosmological.
KeywordsGalaxiesDistances and Redshifts GalaxiesQuasarsGeneral
M. López-Corredoira, “Pending Problems in QSOs,” Inter- national Journal of Astronomy and Astrophysics, Vol. 1, No. 2, 2011, pp. 73-82. doi:10.4236/ijaa.20011.12011
M. J. Rees, “Appearance of Relativistically Expanding Radio Sources,” Nature, Vol. 211, 1966, pp. 468-470. doi:10.1038/211468a0
J. A. Zensus and T. J. Pearson, “Superluminal Radio Sources: Introduction,” In: J. A. Zensus and T. J. Pearson, Eds., Superluminal Radio Sources, Cambridge University Press, Cambridge, 1987
J. V. Narlikar, “Noncosmological Redshifts,” Space Science Reviews, Vol. 50, No. 3-4, 1989, pp. 523-614. doi:10.1007/BF00228382
M. B. Bell, “Further Evidence That the Redshifts of AGN Galaxies May Contain Intrinsic Components,” Astrophysical Journal Letters, Vol. 667, No. 2, 2007, pp. L129- L132.
K. R. Lind and R. D. Blandford, “Semidynamical Models of Radio Jets: Relativisitc Beaming and Source Counts,” The Astrophysical Journal, Vol. 295, 1985, pp. 358-367. doi:10.1086/163380
K. I. Kellermann, R. C. Vermeulen, J. A. Zensus and M. H. Cohen, “Sub-Milliarcsec Imaging of Quasars and Active Galactic Nuclei,” The Astronomical Journal, Vol. 115, No. 4, 1998, pp. 1295-1318. doi:10.1086/300308
K. I. Kellermann, et al., “Sub-Milliarcsec Imaging of Quasars and Active Galactic Nuclei. III. Kinematics of Parsec-Scale Radio Jets,” The Astrophysical Journal, Vol. 609, No. 2, 2004, pp. 539-563. doi:10.1086/421289
C. M. Urry and P. Padovani, “Unified Schemes for Radio- Loud Active Galactic Nuclei,” Publications of the Astronomical Society of the Pacific, Vol. 107, No. 715, 1995, pp. 803-845. doi:10.1086/133630
Y. Y. Kovalev, M. L. Lister, D. C. Homan and K. I. Kellermann, “The Inner Jet of the Radio Galaxy M87,” Astrophysical Journal Letters, Vol. 668, No. 1, 2007, pp. L27-L30.
J. A. Biretta, W. B. Sparks and F. Macchetto, “Hubble Space Telescope Observations of Superluminal Motion in the M87 Jet,” The Astrophysical Journal, Vol. 520, No. 2, 1999, pp. 621-626. doi:10.1086/307499
M. B. Bell, “Evidence in Support of the Local Quasar Model from Inner Jet Structure and Angular Motions in Radio Loud AGN,” 2007, arXiv:0711.4531
J. G. Bolton, F. F. Gardner and M. B. Mackey, “The Parkes Catalogue of Radio Sources, Declination Zone –20? to –60?,” Australian Journal of Physics, Vol. 17, No. 3, 1964, pp. 340-372. doi:10.1071/PH640340
G. K. Miley, “The Radio Structure of Quasars- A Statistical Investigation,” Monthly Notices of the Royal Astronomical Society, Vol. 152, 1971, pp. 477-490.
P. Alexander and J. P. Leahy, “Ageing and Speeds in a Representative Sample of 21 Classical Double Radio Sources,” Monthly Notices of the Royal Astronomical Society, Vol. 225, 1987, pp. 1-26.
K. Cleary, C. R. Lawrence, J. A. Marshall, L. Hao and D. Meier, “Spitzer Observations of 3C Quasars and Radio Galaxies: Mid Infrared Properties of Powerful Radio Sources,” The Astrophysical Journal, Vol. 660, No. 1, 2007, pp. 117-145. doi:10.1086/511969
C. P. O’Dea, et al., “Physical Properties of Very Powerful FRII Radio Galaxies,” Astronomy and Astrophysics, Vol. 494, No. 2, 2009, pp. 471-488. doi:10.1051/0004-6361:200809416
R. A. Laing, P. Parma, H. R. De Ruiter and R. Fanti, “Asymmetries in the Jets of Weak Radio Galaxies,” Monthly Notices of the Royal Astronomical Society, Vol. 306, No. 3, 1999, pp. 513-530. doi:10.1046/j.1365-8711.1999.02548.x
R. A. Laing and A. H. Bridle, “Relativistic Models and the Jet Velocity Field in the Radio Galaxy 3C 31,” Monthly Notices of the Royal Astronomical Society, Vol. 336, No. 1, 2002, pp. 328-352. doi:10.1046/j.1365-8711.2002.05756.x
R. A. Laing and A. H. Bridle, “Dynamical Models for Jet Deceleration in the Radio Galaxy 3C 31,” Monthly Notices of the Royal Astronomical Society, Vol. 336, No. 4, 2002, pp. 1161-1180. doi:10.1046/j.1365-8711.2002.05873.x
R. A. Laing, J. R. Canvin, A. H. Bridle and M. J. Hardcastle, “A Relativistic Model of the Radio Jets in 3C 296,” Monthly Notices of the Royal Astronomical Society, Vol. 372, No. 2, 2006, pp. 510-536. doi:10.1111/j.1365-2966.2006.10903.x
R. A. Laing and A. H. Bridle, “Jet-Environment Interactions in FRI Radio Galaxies,” In: T. A. Rector and D. S. Young, Eds., Extragalactic Jets: Theory and Observation from Radio to Gamma Rays, ASP Conference Series, Vol. 386, 2008, pp. 70-79.
A. P. Marscher, “Effects of Nonuniform Structure on the Derived Physical Parameters of Compact Synchrotron Sources,” The Astrophysical Journal, Vol. 216, 1977, pp. 244-256. doi:10.1086/155467
A. P. Marscher, “The Core of a Blazar Jet,” In: T. A. Rector and D. S. Young, Eds., Extragalactic Jets: Theory and Observations from Radio to Gamma Rays, ASP Conference Series, Vol. 386, 2008, pp. 437-443.
A. P. Marscher, “Jets in Active Galactic Nuclei,” 2009, arXiv:0909.2576v1[astroph.HE]
M. B. Bell and S. P. Comeau, “The Point of Origin of the Radio Radiation from the Unresolved Cores of Radio- Loud Quasars,” Astrophysics and Space Science, Vol. 325, No. 1, 2010, pp. 31-36. doi:10.1007/s10509-009-0162-z
R. Chatterjee, et al., “Correlated Multi-wave Variability in the Blazar 3C 279 from 1996 to 2007,” The Astrophysical Journal, Vol. 689, No. 1, 2008, pp. 79-94. doi:10.1086/592598
S. G. Jorstad, et al., “Flaring Behavior of the Quasar 3C 454.3 across the Electromagnetic Spectrum,” 2010, arXiv:1003.4293 [astroph.CO]
M. Sikora, R. Moderski and G. M. Madejski, “3C 454.3 Reveals the Structure and Physics of Its ‘Blazar Zone’,” The Astrophysical Journal, Vol. 675, No. 1, 2008, pp. 71- 78. doi:10.1086/526419
D. C. Homan, J. F. C. Wardle, C. C. Cheung, D. H. Roberts and J. M. Attridge, “PKS 1510-089: A Head-on View of a Relativistic Jet,” The Astrophysical Journal, Vol. 580, No. 2, 2002, pp. 742-748. doi:10.1086/343894
R. S. Dixon, “A Master List of Radio Sources,” Astrophysical Journal Supplement, Vol. 20, 1970, pp. 1-503. doi:10.1086/190216
J. Ekers, “The Parkes Catalogue of Radio Sources: Declination Zone +20? to –90?,” Australian Journal of Physics Astrophysical Supplement, Vol. 7, 1969, pp. 3-75.
J. Pilkington and P. Scott, “A Survey of Radio Sources Between Declinations 20? and 40?,” Memoirs of the Royal Astronomical Society, Vol. 69, 1964, pp. 183-192.
J. Gower, P. Scott and D. Wills, “A Survey of Radio Sources in the Declination Ranges –07? to 20o and 40? to 80?,” Memoirs of the Royal Astronomical Society, Vol. 71, 1967, pp. 49-144.
D. Murphy, I. Browne and R. Perley, “VLA Observations of a Complete Sample of Core-Dominated Radio Sources,” Monthly Notices of the Royal Astronomical Society, Vol. 264, No. 2, 1993, pp. 298-318.
P. Kharb, M. L. Lister and N. J. Cooper, “Extended Radio Emission in MOJAVE Blazars: Challenges to Unification,” The Astrophysical Journal, Vol. 710, 2010, pp. 746-782.
T. Hovatta, E. Valtaoja, M. Tornikoski and A. Lahteenmaki, “Doppler Factors, Lorentz Factors and Viewing Angles for Quasars, BL Lacertae Objects and Radio Galaxies,” Astronomy and Astrophysics, Vol. 494, No. 2, 2009, pp. 527-537. doi:10.1051/0004-6361:200811150
E. A. Carrara, Z. Abraham, S. C. Unwin and J. A. Zensus, “The Milliarcsecond Structure of the Quasar 3C 279,” Astronomy and Astrophysics, Vol. 279, No. 1, 1993, pp. 83-89.
P. Scheuer, “Tests of Beaming Models,” In: J. A. Zensus, and T. J. Pearson, Eds., Superluminal Radio Sources, Cambridge University Press, Cambridge, 1987, pp. 104- 113.
T. Hovatta, E. Valtaoja, M. Tornikoski and A. Lahteenmaki, “Doppler Factors, Lorentz Factors, and Viewing Angles for Quasars, BL Lacertae Objects and Radio Galaxies (Erratum),” Astronomy and Astrophysics, Vol. 498, No. 3, 2009, pp. 723-723. doi:10.1051/0004-6361/200811150e
J. V. Wall and J. A. Peacock, “Bright Extragalactic Radio Sources at 2.7 GHz, III. The All-Sky Catalogue,” Monthly Notices of the Royal Astronomical Society, Vol. 216, No. 1, 1985, pp. 173-192.
R. A. Laing, J. M. Riley and M. S. Longair, “Bright Radio Sources at 178 MHz: Flux Densities, Optical Identifications and the Cosmological Evolution of Powerful Radio Galaxies,” Monthly Notices of the Royal Astronomical Society, Vol. 204, 1983, pp. 151-187.
H. Kühr, A. Witzel, I. I. K. Pauliny-Toth and U. Nauber, “A Catalogue of Extragalactic Radio Sources Having Flux Densities Greater than 1 Jy at 5 GHz,” Astronomy and Astrophysics Supplement Series, Vol. 45, 1981, pp. 367-430.
M. Stickel, K. Meisenheimer and H. Kühr, “The Optical Identification Status of the 1 Jy Radio Source Catalogue,” Astronomy and Astrophysics Supplement Series, Vol. 105, No. 2, 1994, pp. 211-234.
J. Lovegrove, R. E. Schild and D. Leiter, “Discovery of Universal Elliptical Outflow Structures in Radio-Quiet Quasars,” 2010, arxiv:1003.5497.
J. Lovegrove, R. E. Schild and D. Leiter, “Discovery of Universal Outflow structures above and below the Accretion Disc Plane in Radio-Quiet Quasars,” Monthly Notices of the Royal Astronomical Society, Vol. 412, No. 4, 2011, pp. 2631-2640. doi:10.1111/j.1365-2966.2010.18082.x