AAS Meeting #193 - Austin, Texas, January 1999
Session 90. Ultra-Luminous IR Galaxies/AGN - The Central Regions
Oral, Friday, January 8, 1999, 2:00-3:30pm, Room 8 (A,B,C)

## [90.06] UV Spectra of Narrow-line Seyfert 1 Galaxies: A High Density BELR

J. Kuraszkiewicz (SAO \& NCAC-Warsaw, Poland), B.J. Wilkes (SAO), B. Czerny (NCAC-Warsaw, Poland), S. Mathur (SAO)

We compare the UV spectra of narrow-line Seyfert 1 (NLSy1) galaxies with the normal'' broad line AGN and show that the NLSy1s are characterized by narrower UV lines, weaker CIV\lambda1549, CIII]\lambda1909 emission and stronger SiIV+OIV]\lambda1400, SiIII]\lambda1892, AlIII\lambda1857 emission. We show that such spectra are the result of BLR cloud densities that are larger than normal by factors 10-100, and with a lower ionization parameter. This is due to the steep soft X-ray spectra (which characterize the NLSy1 SEDs) which change the conditions in the two phase cloud-intercloud medium, resulting in higher BLR cloud densities and larger BLR radii. We also show that the steep soft and hard X-ray indices, observed in NLSy1s, can be explained by an accretion disk and corona model with large L/LEdd ratios.

These UV properties add to the optical and X-ray properties known to be part of the Boroson & Green eigenvector 1. We propose that the L/LEdd is the physical parameter driving this eigenvector.