The blueshift of the [O III] emission line in narrow-line Seyfert 1 galaxies

We investigate the radial velocity difference between the narrow emission-line components of [O III] gimel 5007 and H beta in a sample of 150 Sloan Digital Sky Survey narrow-line Seyfert 1 galaxies. Seven 'blue outliers' with [O III] blueshifted by more than 250 km s(-1) are found. A strong correlation between the [O III] blueshift and the Eddington ratio is found for these seven 'blue outliers'. For the entire sample, we found a modest correlation between the blueshift and the linewidth of the narrow component of the [O III] line. The reflected profile of [O III] indicates two kinematically and physically distinct regions. The [O III] linewidth depends not only on the bulge stellar gravitational potential, but also on the central black hole potential.