Radio Identifications of Recently Discovered Planetary Nebulae

Using the 1.4 GHz NRAO VLA Sky Survey (NVSS) images and source catalog, we identified 315 radio sources stronger than ≈2.5 mJy among over 1000 recently discovered planetary nebulae north of J2000 declination δ = -40°. Two-thirds of these radio sources are weaker than 10 mJy at 1.4 GHz. This result is a uniform supplement to the previous NVSS radio identification of known PNe and a large homogeneous sample including over 1000 PNe with NVSS sources is obtained. By examining the radio properties of PNe, it is found that most of the planetary nebulae detected at both 1.4 and 5.0 GHz are optically thick at λ = 20 cm.