Context. Many active galactic nuclei (AGN) and particularly narrow-line Seyfert 1 (NLS1) galaxies, usually exhibit blueshifts and blue wings in several emission lines, which are mainly associated with outflows and strong winds. Although there is no clear evidence of the physical origin of the [OIII] blue wings, it has been suggested that they could be emitted from the inner parts of the narrow-line region (NLR). Aims. In order to study the radial velocity difference between the narrow component of Hβ and the core component of [OIII]λ5007 and the asymmetric emission of this forbidden line, we investigate a sample of NLS1 galaxies . One of the aims of this paper is to analyze the blue wings of the [OIII]λ5007 profiles and their relation with the central engine. Methods. We have obtained and studied medium-resolution spectra (190 km s −1 FWHM at Hβ) of a sample of 28 NLS1 galaxies in the optical range 4300 -5200Å. We performed Gaussian decomposition to the Hβ and [OIII]λλ4959,5007 emission profiles in order to study the distinct components of these lines. Results. A new blue outlier galaxy is found, in which the center of the core component of [OIII] is blueshifted by 405 km s −1 relative to the center of the narrow component of Hβ line. We confirmed a previously known correlation between the blueshift and the full width half maximum (FWHM) of the core component of [OIII]λ5007 line. We also corroborated the correlation between the latter and the velocity of the centroid of the blue wing. On the other hand, by studying the radial velocity difference between the blue end of the asymmetric emission and the centroid of the core component of [OIII], we found a correlation between it and the central black hole mass and, therefore, with the luminosity of the broad component of Hβ. Finally, we found a moderate correlation between the luminosity of the [OIII] blue wing and the black hole mass. Conclusions. These results suggest that the asymmetric emission of the [OIII] lines is related to the central engine, not only through the black hole but also in the intensity of the AGN, which is in agreement with previous results.

We present an observational study about the effects of the interactions in the kinematics, stellar population and abundances of the components of the galaxy pair AM 2306-721. Rotation curves for the main and companion galaxies were obtained, showing a deprojected velocity amplitude of 175 and 185 km s −1 , respectively. The interaction between the main and companion galaxies was modelled using numerical N-body/hydrodynamical simulations, with the result indicating that the current stage of the merger would be about 250 Myr after perigalacticum. The spatial variation in the distribution of the stellar-population components in both galaxies was analysed by fitting combinations of stellar-population models of different age groups. The central region of main galaxy is dominated by an old (5-10 Gyr) population, while significant contributions from a young (200 Myr) and intermediate (1 Gyr) components are found in the disc, and being enhanced in the direction of the tidal features. The stellar population of the companion galaxy is overall much younger, being dominated by components with 1 Gyr or less, quite widely spread over the whole disc. Spatial profiles of the oxygen abundance were obtained from a grid of photoionization models using the R 23 line ratio. The disc of the main galaxy shows a clear radial gradient, while the companion galaxy presents oxygen abundance relatively homogeneous across the disc. The absence of an abundance gradient in the secondary galaxy is interpreted in terms of mixing by gas flows from the outer parts to the centre of the galaxy due to the gravitational interaction with the more massive primary.