Investigation of Stellar Kinematics and Ionized gas Outflows in Local (U)LIRGs

TL;DR

This study analyzes stellar and gas outflow properties in 1106 local (U)LIRGs, revealing that AGN activity significantly enhances ionized gas outflows and suggesting negative feedback effects in gas-rich AGN hosts.

Contribution

It provides a comprehensive analysis of stellar kinematics and ionized gas outflows in a large sample of local (U)LIRGs, highlighting the role of AGNs in driving powerful outflows.

Findings

AGN (U)LIRGs show higher outflow incidence (72%) than non-AGNs (39%)

Extreme outflow velocities up to 2300 km/s observed in AGN ULIRGs

Negative correlation between outflow velocity and sSFR in AGN hosts with high SFRs

Abstract

We explore properties of stellar kinematics and ionized gas in a sample of 1106 local (U)LIRGs from the AKARI telescope. We combine data from $Wide-field\ Infrared\ Survey\ Explorer$ (WISE) and Sloan Digital Sky Survey (SDSS) Data Release 13 (DR13) to fit the spectral energy distribution (SED) of each source to constrain the contribution of active galactic nuclei (AGNs) to the total IR luminosity and estimate physical parameters such as stellar mass and star-formation rate (SFR). We split our sample into AGNs and weak/non-AGNs. We find that our sample is considerably above the main sequence. The highest SFRs and stellar masses are associated with ULIRGs. We also fit the H$\beta$ and H$\alpha$ regions to characterize the outflows. We find that the incidence of ionized gas outflows in AGN (U)LIRGs ($\sim$ 72\%) is much higher than that in weak/non-AGN ones ($\sim$ 39\%). The AGN ULIRGs have extreme outflow velocities (up to $\sim$ 2300 km s$^{-1}$) and high mass-outflow rates (up to $\sim$ 60 \solarm~yr$^{-1}$). Our results suggest that starbursts are insufficient to produce such powerful outflows. We explore the correlations of SFR and specific SFR (sSFR) with ionized gas outflows. We find that AGN hosts with the highest SFRs exhibit a negative correlation between outflow velocity and sSFR. Therefore, in AGNs containing large amounts of gas, the negative feedback scenario might be suggested.