2021MNRAS.502.3312S

The spectra of active galactic nuclei usually exhibit wings in some emission lines, such as [O III]λλ5007, 4959, with these wings generally being blueshifted and related to strong winds and outflows. The aim of this work was to analyse the [O III] emission lines in broad-line Seyfert 1 (BLS1) galaxies in order to detect the presence of wings, and to study the [O III] line properties and their possible connection with the central engine. In addition, we attempted to compare the black hole mass distribution in both BLS1 galaxies with symmetric and blue-asymmetric [O III] profiles. For this purpose, we carried out a spectroscopic study of a sample of 45 nearby southern BLS1 galaxies from the Six Degree Field Galaxy survey. The [O III] emission lines were well-fitted using a single Gaussian function in 23 galaxies, while 22 objects presented a wing component and required a double-Gaussian decomposition. By computing the radial velocity difference between the wing and core centroids (i.e. Δv), we found 18 galaxies exhibiting blueshifted wings, 2 objects presenting red wings, and 2 galaxies showing symmetric wings (Δv = 0). Moreover, Δv was slightly correlated with the black hole mass. In addition, we computed the radial velocity difference of the blue-side full extension of the wing relative to the centroid of the core component through the blue emission parameter, which revealed a correlation with black hole mass, in agreement with previous results reported for narrow-line galaxies. Finally, in our sample, similar black hole mass distributions were observed in both BLS1 galaxies with symmetric and blueshifted asymmetric [O III] profiles.