Landing page for project EB092

We request EVN+MERLIN observations of seven radio galaxies with double-sided jets to study their collimation profile and the parabolic-to-conical transition region, if existing. Two-sided AGN are less affected by differential Doppler-boosting and could facilitate a more unbiased study. We aim to image the sources at three EVN bands (C, X, and K) to measure accurately the jet transverse width evolution and so to understand the physical mechanisms behind the acceleration and collimation. Depending on the collimation profile theoretical models, including magnetic self-collimation and a confinement by the accretion disc, can be tested. A large subset of AGN jets reveal a change from parabolic to conical collimation close to the sphere of gravitational influence of the black hole. However, most of the until now analyzed radio galaxies deviate from this picture by revealing break points much closer to the central engine or no parabolic region at all. The number of one-sided jets in these studies is by far larger in comparison to double-sided radio galaxies, which makes statistically relevant studies nearly impossible. Successful observations will also allow us to extrapolate the continuum spectrum towards higher frequencies for possible future mm-VLBI observation.

This data is part of the archive of VLBI data maintained by JIVE on behalf of the EVN, a network of radio telescopes located primarily in Europe and Asia, with additional antennas in South Africa. The EVN archive itself has the DOI https://doi.org/10.17616/R3Z197