Search for new Galactic supernova remnants at radio frequencies

The extended radio sources from the NVSS survey are proposed as new previously non-cataloged Galactic supernova remnants (SNR). The radio continuum spectrum is the key property of the Galactic extended sources which distinguish them as supernova remnants from thousands of cataloged radio sources. We examined the RATAN-600 Galactic plane survey (Trushkin, 1998) at 0.96 and 3.9 GHz and the NVSS maps at 1.4 GHz in order to find new unknown SNRs in the Galaxy. Also we used the abundant radio data of CATS database: http://cats.sao.ru (Verkhodanov et al., 1997). They have non-thermal radio spectra from measurements with the RATAN-600 radio telescope and from Bonn survey at 1.4 and 2.7 GHz. We selected 15 SNR candidates using the criteria of a non-thermal spectrum, an extended, often shell-like structure, and linear polarization data (NVSS catalog/maps). Indeed, some peaks of brightness in the shells are strongly polarized at 1.4 GHz. As the first result of such a search we detected the new SNR G16.2-2.7 (Trushkin, 1999c) and some new candidates recently observed with the RATAN-600 radio telescope. New SNR spectra could be plotted with an "on-line" procedure of the SNR database: http://cats.sao.ru/(similar to)satr/SNR/.