Speaker
Description
The high angular resolution and sensitivity of VLBI offers a unique tool to identify and study AGN and star-formation activity over cosmic time. VLBI observations are crucial for identifying young radio sources and unveiling older restarted radio sources. Also, radio imaging over a large range of angular scales is needed to determine the role of black hole feedback and jet-induced star formation in galaxies. To answer these questions and to find rare radio sources, such as gravitational lenses and binary/dual AGN, all-sky VLBI surveys are needed. Despite recent technical advances, such as multiple phase centre correlation and multi-source self-calibration, only a limited part of the sky has been observed within a few well-studied fields. To enter the realm of large statistical studies, a significantly larger area of sky must be observed, which would limit the VLBI available time for other single-target science projects.
SWEEPS (Synoptic Wide-field EVN–eMERLIN Public Survey) is a commensal survey mode for the EVN+e-MERLIN, where single-target PI-led observations are re-correlated at the position of all known radio sources within 12 arcmin. Initially, the phase centres are selected using the LoTSS survey program of LOFAR. In the future, however, additional phase centres will be provided by a wide-field image using the short baselines of e-MERLIN that will be generated on-the-fly for the initial correlation. From archival data, full implementation of this program would observe on average ~10,500 radio sources per year without any additional observing time. Here, we present an overview of the upcoming survey programme as well as results and methods from the pilot program, where we detected 21 new VLBI objects in the data of a PI-led single target observation.
