Testing the unified model with an infrared-selected sample of Seyfert galaxies

We present a series of statistical tests done to a sample of 29 Seyfert 1 a nd 59 Seyfert 2 galaxies selected from mostly isotropic properties, their f ar-infrared fluxes and warm infrared colors. Such selection criteria provid e a profound advantage over the criteria used by most investigators in the past, such as ultraviolet excess. These tests were done using ground-based high-resolution Very Large Array A-configuration 3.6 cm radio and optical B and I imaging data. From the relative number of Seyfert 1's and Seyfert 2' s, we calculate that the torus half-opening angle is 48 degrees. We show th at, as seen in previous papers, there is a lack of edge-on Seyfert 1 galaxi es, suggesting that dust and gas along the host galaxy disk probably play a n important role in hiding some nuclei from direct view. We find that there is no statistically significant difference in the distribution of host gal axy morphological types and radio luminosities of Seyfert 1's and Seyfert 2 Is, suggesting that previous results showing the opposite may have been due to selection effects. The average extension of the radio emission of Seyfe rt 1's is smaller than that of Seyfert 2's by a factor of similar to2-3, as predicted by the unified model. A search for galaxies around our Seyferts allows us to put a lower and an upper limit on the possible number of compa nions around these galaxies of 19% and 28%, respectively, with no significa nt difference in the number of companion galaxies between Seyfert 1's and S eyfert 2's. We also show that there is no preference for the radio jets to be aligned closer to the host galaxy disk axis in late-type Seyferts, unlik e results claimed by previous papers. These results, taken together, provid e strong support for a uniDed model in which type 2 Seyferts contain a toru s seen more edge-on than the torus in type 1 Seyferts.