# Properties of ionized outflows in MaNGA DR2 galaxies

## TL;DR

This study systematically analyzes ionized outflows in over 2700 nearby galaxies from MaNGA DR2, revealing their properties, dependence on galaxy type, and implications for galaxy evolution and metal retention.

## Contribution

It provides the first large-scale characterization of ionized outflows across diverse galaxy types and star formation rates using spatially-resolved spectroscopy.

## Key findings

- Ionized outflows detected in ~7% of Halpha-emitting regions.
- Outflow kinematics vary with ionization mechanism, from SF to LIER regions.
- Higher outflow velocities are associated with larger galaxy stellar masses.

## Abstract

We present the results from a systematic search and characterization of ionized outflows in nearby galaxies using the data from the second Data Release of the MaNGA Survey (DR2; > 2700 galaxies, z < 0.015). Using the spatially-resolved spectral information provided by the MANGA data, we have identified ~5200 Halpha-emitting regions across the galaxies and searched for signatures of ionized outflows. We find evidence for ionized outflows in 105 regions from 103 galaxies, roughly 7% of all the Halpha-emitting galaxies identified in this work. Our analysis allows us to study ionized outflows in individual regions with SFRs down to ~0.01 Msun yr-1, extending the ranges probed by previous works. The kinematics of the outflowing gas are strongly linked to the type of ionization mechanism: regions characterized by LIER emission host outflows with more extreme kinematics (FWHM_broad ~900 km/s), followed by those originated in AGN (~550 km/s), `Intermediate' (~450 km/s) and SF (~350 km/s) regions. Moreover, in most of the outflows we find evidence for gas ionized by shocks. We find a trend for higher outflow kinematics towards larger stellar masses of the host galaxies but no significant variation as a function of star formation. The fraction of outflowing gas that can escape from galaxies decreases towards higher dynamical masses, contributing to the preservation of the mass-metallicity relation by regulating the amount of metals in galaxies. Finally, assuming that the extensions of the outflows are significantly larger than the individual star-forming regions, as found in previous works, our results also support the presence of star formation within ionized outflows, as recently reported by Maiolino et al. 2017 and Gallagher et al. 2019.