Seyfert galaxies are divided into two classes, based upon the widths of their spectral emission features. The Seyfert 1 galaxy above has hydrogen emission features with very large widths, indicating that the gas in the galaxy's central regions is moving with velocities of several thousand km/sec (Seyfert 1 galaxies show velocities up to almost 0.1c).
The Seyfert 2 galaxy shown above has much narrower emission features implying much lower velocities (note that the Seyfert 1 above shows narrow features as well).