The NRAO VLA Sky Survey

The NRAO VLA Sky Survey (NVSS) covers the sky north of J2000.0 δ = -40° (82% of the celestial sphere) at 1.4 GHz. The principal data products are (1) a set of 2326 4° × 4° continuum "cubes" with three planes containing Stokes I, Q, and U images plus (2) a catalog of almost 2 × 106 discrete sources stronger than S ≈ 2.5 mJy. The images all have θ = 45'' FWHM resolution and nearly uniform sensitivity. Their rms brightness fluctuations are σ ≈ 0.45 mJy beam-1 ≈ 0.14 K (Stokes I) and σ ≈ 0.29 mJy beam-1 ≈ 0.09 K (Stokes Q and U). The rms uncertainties in right ascension and declination vary from ≲1'' for the N ≈ 4 × 105 sources stronger than 15 mJy to 7'' at the survey limit. The NVSS was made as a service to the astronomical community. All data products, user software, and updates are being released via the World Wide Web as soon as they are produced and verified.