Landing page for project EC066

This is the conclusive request of a previously accepted proposal (EC064A-B) aimed at confirming the blazar nature of a well-defined sample of high redshift sources selected from the CLASS survey. We now propose to follow-up the 5 new high redshift (4<z<5) blazar candidates discovered after a recent spectroscopic run at the LBT telescope. This final list includes the second most distant blazar candidate ever discovered (z=5.4). The aim is either to confirm or to rule out the blazar nature of these flat radio spectrum sources by measuring the brightness temperature (Tb) of the components that will be detected at m.a.s. resolution. A Tb well above the equipartition temperature is a strong signature of the presence of relativistic beaming. Results from these observations will be then evaluated together with what has been obtained with a SED-modelling method, that provides independent estimates of the beaming parameters, and a conclusion on the source's orientation will be finally given. This is a unique flux-limited and completely identified blazar sample at z>4 and It will be used to determine the statistical properties of radio loud AGN at early cosmic epochs.

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