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Title: Multiepoch VLBI observations of 4C 39. 25 - superluminal motion amid stationary structure

Journal Article · · Astrophys. J.; (United States)
DOI:https://doi.org/10.1086/184839· OSTI ID:6270147

Eight VLBI maps of the quasar 4C 39.25 are presented, covering the time interval November 1979 to July 1985. During this period the compact components at the eastern and western ends of the source remained roughly stationary with respect to each other. A third component emerged from the western component in 1982 and proceeded to move (relative to the other two components) eastward at a rate of 0.16 + or - 0.02 marcsec per year. This corresponds to an average apparent speed between 3.2c and 8.4c for Hubble's constant between 100 and 50 km/s Mpc and q0 between 1 and 0. This superluminal motion contrasts with the stationary structure observed in the 1970s and also still observed between the eastern and western ends of the source. Possible explanations include superluminal feeding of a stationary compact counterpart to a classical radio lobe, an obstacle in a relativistic jet, a relativistic jet which alternatively expands and contracts owing to gradients in the confining pressure, and gravitational lensing of the compact radio emission. 20 references.

Research Organization:
Interferometrics Inc., Greenbelt, MD; Boston Univ., MA; Max-Planck-Institut fuer Radioastronomie, Bonn, West Germany; Instituto de Astrofisica de Andalucia, Granada, Spain; National Radio Astronomy Observatory, Charlottesville, VA
OSTI ID:
6270147
Journal Information:
Astrophys. J.; (United States), Vol. 314
Country of Publication:
United States
Language:
English