Optical Observations of "cold" Seyfert 2 Galaxies

We present optical spectra for a sample of 43 Seyfert 2 galaxies selected from the Point Source Catalog of the IRAS Survey and the catalog of quasars and active nuclei (Veron et al.2000).Our goal is to search for correlations between emission-line properties and infrared warmth for the sources and thereby test whether two types of Seyfert 2 galaxies exist.Since not all of the sources selected are "real" Seyfert 2 galaxies, we have reclassified these galaxies by the emissionline ratios.The distribution from Seyfert 1.9 galaxies, Seyfert 2 galaxies, LINERs, HII region and composite spectra are 23%, 30%, 7%, 5% and 35%, respectively.We find that there is a distinct correlation between ionization and dust temperature in both "warm" and "cold" Seyfert 2 galaxies, which suggests that there is no evidence for the existence of two types of Seyfert 2 galaxies. The mechanism of the correlation between OⅢ 5007/Hβ and α(25, 60)is also briefly discussed.