Astronomy and Astrophysics – Astrophysics
Scientific paper
1995-06-22
Astronomy and Astrophysics
Astrophysics
28 pages, 4 tables, 8 figures all available under request from tventuri@astbo1.bo.cnr.it
Scientific paper
We present 5 GHz global VLBI observations of the two Fanaroff Riley Type I radio galaxies B2 0836+29 and 3C465 (2335+26). For 3C465 we present also 1.7 GHz and 8.4 GHz global VLBI data. In addition VLA observations were used to obtain arsecond resolution continuum and polarization maps at 5 GHz. Both sources are very asymmetric on the parsec-scale, with a core and a one-sided jet, aligned with the main arcsecond scale jet. We place a limit on the milliarcsecond jet to counterjet brightness ratio B$_{jet}$/B$_{cjet}$ \gtsim 20 and \gtsim 30 for B2 0836+29 and 3C465 respectively. For 3C465 the strong asymmetry holds to the kiloparsec scale. The brightness asymmetry and the ratio between the core radio power and total radio power allow us to constrain the jet velocity close to the core and the orientation of the radio structure with respect to the line of sight. The results suggest that the plasma speed is relativistic on the parsec scale for both sources, i.e. v$_{jet}$ \gtsim 0.75c for B2 0836+29 and v$_{jet}$ \gtsim 0.6c for 3C465. While v$_{jet}$ decreases from the parsec to the kiloparsec scale in B2 0836+29, in 3C465 the very high v$_{jet}$ holds all the way to the kiloparsec-scale {\t bright spot}. Our results are in agreement with the unification scheme suggestion that FR-I radio galaxies are the unbeamed poulation of BL-Lac objects. Furthermore, they reinforce the idea that the central engine in FR-I and FR-II radio galaxies must be qualitatively similar. The different radio morphology could then be due either to an intrinsically different nuclear power, which affects the torus geometry or to different conditions in the region beyond the parsec scale, where a significant deceleration in the FR-I jets occurs.
Castaldini C.
Cotton William D.
Feretti Luigina
Giovannini Gabriele
Lara Liana
No associations
LandOfFree
VLBI Observations of a Complete Sample of Radio Galaxies. VI. The Two FR-I Radio Galaxies B2 0836+29 and 3C465 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with VLBI Observations of a Complete Sample of Radio Galaxies. VI. The Two FR-I Radio Galaxies B2 0836+29 and 3C465, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and VLBI Observations of a Complete Sample of Radio Galaxies. VI. The Two FR-I Radio Galaxies B2 0836+29 and 3C465 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-292896