Are wolf-rayet stars able to pollute the interstellar medium of galaxies? results from integral field spectroscopy

We investigate the spatial distribution of chemical abundances in a sample of low metallicity Wolf-Rayet (WR) galaxies selected from the SDSS. We used the integral field spectroscopy technique in the optical spectral range (3700 Å-6850 Å) with PMAS attached to the CAHA 3.5 m telescope. Our statistical analysis of the spatial distributions of O/H and N/O, as derived using the direct method or strong-line parameters consistent with it, indicates that metallicity is homogeneous in five out of the six analysed objects in scales of the order of several kpc. Only in the object WR404 is a gradient of metallicity found in the direction of the low surface brightness tail. In contrast, we found an overabundance of N/O in spatial scales of the order of hundreds of pc associated with or close to the positions of the WR stars in 4 out of the 6 galaxies. We exclude possible hydrodynamical causes, such as the metal-poor gas inflow, for this local pollution by means of the analysis of the mass-metallicity relation (MZR) and mass-nitrogen-to-oxygen relation (MNOR) for the WR galaxies catalogued in the SDSS. © 2013 Enrique Pérez-Montero et al.This work has been partially supported by projects AYA2007-67965-C03-02 and AYA2010-21887-C04-01 of the Spanish National Plan for Astronomy and Astrophysics. The authors thank an anonymous referee for his/her very thorough revision of this paper that has helped to improve it.Peer Reviewe