SDSS-IV MaNGA: enhanced star formation in galactic-scale outflows

Using the integral field unit (IFU) data from Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, we collect a sample of 36 star-forming galaxies that host galactic-scale outflows in ionized gas phase. The control sample is matched in the three-dimensional parameter space of stellar mass, star formation rate, and inclination angle. Concerning the global properties, the outflows host galaxies tend to have smaller size, more asymmetric gas disc, more active star formation in the centre, and older stellar population than the control galaxies. Comparing the stellar population properties along axes, we conclude that the star formation in the outflows host galaxies can be divided into two branches. One branch evolves following the inside-out formation scenario. The other located in the galactic centre is triggered by gas accretion or galaxy interaction, and further drives the galactic-scale outflows. Besides, the enhanced star formation and metallicity along minor axis of outflows host galaxies uncover the positive feedback and metal entrainment in the galactic-scale outflows. Observational data in different phases with higher spatial resolution are needed to reveal the influence of galactic-scale outflows on the star formation progress in detail.