The interferometric imaging mode provides correlated visibility data, just like traditional aperture synthesis radio telescope arrays consisting of antenna elements. The goal of the LOFAR imaging mode is to achieve high fidelity, low noise images of a range of astronomical objects, using customizable observing parameters.
LOFAR can return simple time/frequency beam-formed data instead of, or combined with, interferometric data. Array beams are calculated from the data streams from one or more stations in order to produce time-series and dynamic spectra for high time and frequency resolution applications.
Some Beam Formed modes, and even a combination of them, can be run in parallel with the standard imaging mode. This allows one to simultaneously image a field while recording high time resolution dynamic spectra to probe sub-second variations of any source in the field.
In LBA_SPARSE mode half of the dipoles, distributed across the station, are used. This mode grants an intermediate performance between LBA_INNER (not offered in Cycle 16-19) and LBA_OUTER (offered in Cycles 16-19), with a suppression of the magnitude of the side-lobes compared to the latter.