摘要：TheLOFARtelescope,oneofthelowfrequencyprecursorsofSKA,isbeingusedtosurveythefullnortherncelestialhemisphere in the 120MHz band with unprecedented resolution and sensitivity. This special issue of Astronomy & Astrophysics presents the first data release of the LOFAR Two-metre Sky Survey (LOTSS), along with selected early results. The newly released mosaicked images cover 424 square degrees in a single high galactic latitude field with 6 00 resolution. The release includes an extracted catalog of 326000 sources, complete to 0.35mJy for point sources. 70% of these sources are associated with an optical counterpart, and photometric redshifts are provided for those. The early results of the survey span a wide range of mostly extragalactic topics, from the physics of active galactic nuclei to the intergalactic magnetic field, through interstellar medium and clusters of galaxies. This represents only a small sample of what is yet to come, but already hints at the great potential of the full survey.
