Landing page for project EY045

Compact Symmetric Objects (CSOs) are extragalactic sources with a pair of radio jets and an extent of less than 1 kpc. Episodic CSOs are of particular interest due to the presence of a previous epoch of activity. They exhibit two markedly different structures on mas scales and arcsec scales, separated by a notable emission gap. Furthermore, it has been suggested that the jet production mechanisms in different epochs may not be the same. Here, we propose multi-epoch, joint e-MERLIN+EVN observations at 23 GHz to study the common characteristics of both the mas- and arcsec-scale jets in five episodic CSOs, including apparent speed, viewing angle, dynamic age, and total energy. Particularly, we emphasize the necessity of the participation of the additional four e-MERLIN outstations (Pi, Da, Kn, and Cm) in detecting the arcsec-scale jets. Beyond the common properties, these observations can also contribute to studying the physical properties of individual sources, such as Supermassive Black Hole Binaries (SMBHBs) and gamma-ray-loud radio galaxies.

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