Unified models of Seyfert galaxies , based on viewing angles , successfully explain the observed differences between type 1 and 2 Seyferts .
The existence of a range in accretion rates ( \dot { m } \sim 0.001 - 1 ) relative to the Eddington rate ( from broad-line Seyfert 1s to narrow-line Seyfert 1s or NLS1s ) and the unification of Seyfert galaxies imply that there must be type 2 counterparts of NLS1 galaxies i.e. , Seyfert 2s with high accretion rate or small black hole mass .
One such Seyfert 2 , NGC 5506 , has already been unmasked based on near infra-red spectroscopy .
Here we confirm the above result , and present evidence for two additional type 2 counterparts of NLS1s based on XMM-Newton observations .
The three AGNs NGC 7314 , NGC 7582 and NGC 5506 , with a type 1.9/2 optical spectrum , show extremely rapid variability by factors > 2.4 , \sim 1.3 , and \sim 1.7 in 200 { ~ { } s } , 350 { ~ { } s } and 300 { ~ { } s } , respectively , and steep 2 - 12 { ~ { } keV } spectrum ( \Gamma \gtrsim 2 ) in their intrinsic X-ray emission , characteristic of NLS1 galaxies .
These observations establish the ‘ obscured NLS1 galaxies ’ as a subclass of Seyfert 2 galaxies .