SDSS-IV MaNGA: Enhanced Star Formation in Galactic-scale Outflows

TL;DR

This study uses MaNGA IFU data to analyze 36 star-forming galaxies with galactic-scale outflows, revealing their unique properties and suggesting outflows can both suppress and trigger star formation, indicating complex feedback mechanisms.

Contribution

The paper provides the first detailed analysis of galactic-scale outflows in star-forming galaxies using integral field spectroscopy, highlighting their role in galaxy evolution.

Findings

Outflow host galaxies are smaller with asymmetric gas disks.

Star formation in outflow hosts shows two evolutionary branches.

Enhanced star formation and metallicity indicate positive feedback.

Abstract

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 disk, more active star formation in the center 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 locating in the galactic center 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.