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.
These pages describe the general astronomical capabilities (imaging capability and sensitivity) of LOFAR.
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.
At the moment the only Direct Storage mode that is supported is the write-out of time-series data stored in the Transient Buffer Boards.
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.
The LOFAR Responsive Telescope allows users to trigger the telescope to start their observation within 5 minutes, overriding any lower priority observations. This enables follow-up of transient events such as gamma ray bursts or solar activity.
The full inspection of processed LOFAR imaging data is currently not performed by ASTRON. The user should retrieve the data from the archive and inspect them using the tools described in the LOFAR Imaging Cookbook.