LOFAR LBA Sky Survey First Release

Compared to the preliminary release, direction-dependent errors have been derived and corrected for during the calibration process. This results in a typical sensitivity of 1.55mJy/beam, which is four times better than for the preliminary release, at the target resolution of 15 arcsec. The first data release of the LOFAR LBA Sky Survey covers 650 sqdeg in the HETDEX spring field.

The resultant data products released to the community include mosaic images (I and V Stokes) of the region, and a catalogue of 42463 detected sources and related Gaussian components used to describe the sources' morphologies. Separate catalogues for the six in-band frequencies of 44, 48, 52, 56, 60, and 64MHz are also released. The first data release of LoLSS shows that, despite the influences of the ionosphere and radio frequency interference, LOFAR can conduct large-scale surveys in the frequency window 42-66MHz with unprecedentedly high sensitivity and resolution.

The data can be used to derive unique information on the low-frequency spectral properties of many thousands of sources with a wide range of applications in extragalactic and galactic astronomy.