Shocked POststarburst Galaxy Survey. IV. Outflows in Shocked Post-Starburst Galaxies Are Not Responsible For Quenching

TL;DR

This study investigates shocked post-starburst galaxies, finding that while outflows driven by AGN are present, they are not substantial enough to quench star formation in these galaxies.

Contribution

It provides observational evidence that outflows in SPOGs are insufficient for quenching star formation, challenging previous assumptions about AGN-driven feedback.

Findings

Outflows detected in 22 of 77 SPOGs with ionized gas masses up to 10^5 solar masses.

Positive correlation between AGN luminosity and outflow properties.

Outflows are too low in mass to significantly deplete galaxy gas reserves.

Abstract

Shocked POst-starburst Galaxies (SPOGs) exhibit both emission lines suggestive of shock-heated gas and post-starburst-like stellar absorption, resulting in a unique subset for galaxy evolution studies. We have observed 77 galaxies that fulfilled the SPOGs criteria selection using the DeVeny Spectrograph on the Lowell Discovery Telescope. Our long-slit minor axis spectra detect H$\alpha$ and [O III] in some SPOGs out to 6 kpc above the galactic plane. We find extraplanar ionized gas in 31 targets of our sample overall. Using their internal and external kinematics, we argue that 22 galaxies host outflows with ionized gas masses ranging from $10^2 M_{\odot}$ to $10^5 M_{\odot}$. The rest are likely extended diffuse ionized gas. A positive correlation exists between AGN luminosity and the extraplanar gas extent, velocity dispersion, and mass$\unicode{x2013}\unicode{x2013}$suggesting that the AGN may indeed drive the outflows detected in AGN hosts. The low masses of the extraplanar gas suggest that these outflows are not depleting each galaxy's gas reserves. The outflows, therefore, are not likely a significant quenching mechanism in these SPOGs.