Are Narrow-Line Seyfert 1s Really Strange?

Abstract

Narrow-Line Seyfert 1s (NLS1s) are generally considered to be strange Active Galactic Nuclei (AGNs). Surprisingly, this makes them very useful for constraining models. I discuss what happens when one attempts to qualitatively fit the NLS1 phenomenon using the stellar wind model for AGN line emission (e.g., Kazanas 1989). The simplest way of narrowing profile bases of this model to the widths observed in NLS1s is probably to lower the mass of the supermassive black hole. In a flux-limited and redshift-limited data set, this is indeed similar to increasing L/L_Edd. Because the broad line region (BLR) of the stellar line emission model scales with the tidal radius of the stars, this model predicts maximal BLR velocities of FWZI proportional (L/L_Edd)^(-1/3). This implies that the black holes of NLS1s are approximately 3^3=27 times less massive than those in other Seyfert 1s if the stellar line emission model is correct. Another consequence of increasing L/L_Edd in this model is that it results in an increase in the wind edge densities. NLS1 spectra appear to support this result as well. Even the collateral features of NLS1s, such as the line asymmetries and continuum properties, appear to be easily explained within the context of this model. For better or worse, if the stellar wind line emission is correct, NLS1s are not much stranger than other AGNs.