The ViCTORIA project: Description of a multi-frequency radio survey of the Virgo galaxy cluster

The Virgo cluster is the closest and richest nearby galaxy cluster. It is still in the formation process, with a number of sub-clusters undergoing merging and interactions. Although a great laboratory to study galaxy evolution and cluster formation, its large apparent size and the severe dynamic range limitations due to the presence of the bright radio source Virgo A (M 87) reduced the ability of past wide-area radio surveys to image the region with high levels of sensitivity and fidelity. In this paper we describe the Virgo Cluster multi-Telescope Observations in Radio of Interacting galaxies and AGN (ViCTORIA) project. The survey and its data reduction strategy are designed to mitigate the challenges of this field and deliver images from 42 MHz to 1.7 GHz frequencies of the Virgo cluster about 60 times deeper than existing data; final deliberables will include polarisation images and a blind H I survey aimed at mapping seven times more galaxies than previous experiments without selection biases. Data have been collected with the Low-Frequency Array (LOFAR) using both the Low Band Antenna (LBA) and the High Band Antenna (HBA) systems and with MeerKAT in L-band, including polarisation and enough frequency resolution to conduct local H I studies. At the distance of Virgo, current radio instruments have the resolution to probe scales of ∼500 pc and the sensitivity to study dwarf galaxies, which are the most fragile systems given their shallow gravitational potential wells, making Virgo a unique laboratory to study galaxy evolution and AGN feedback in a rich environment. In this work, we present some preliminary results including the highest resolution images of the radio emission surrounding M 87 ever captured that show that the lobes are filled with filamentary structures. The combination of the presented radio surveys with state-of-the-art optical (NGVS, VESTIGE), UV (GUViCS), and X-ray (eROSITA) surveys will massively increase the scientific output from the studies of the Virgo cluster, making the ViCTORIA Project's legacy value outstanding.