Double-peaked Narrow Emission-Line Galaxies in SDSS-IV MaNGA

TL;DR

This study analyzes double-peaked narrow emission lines in galaxies from SDSS-IV MaNGA, revealing correlations between galaxy features and emission-line components, and classifies these components based on their physical properties.

Contribution

It introduces a new classification of double-peaked emission-line components in galaxies and uncovers correlations with galaxy features like bars, AGN activity, and tidal interactions.

Findings

Identified 5,420 double-peaked emission-line spaxels in 304 galaxies.

Classified DPSs into three groups based on velocity and position.

Discovered correlations between galaxy features and emission-line components.

Abstract

Narrow emission lines in a galaxy's spectrum that show double peaks indicate the presence of distinct gas components with different velocities, and its physical origin remains uncertain. This study uses galaxies from the final MaNGA data release to detect double-peaked narrow emission-line spaxels (DPSs) by examining the double Gaussian profiles of the H$ \alpha $-[N \uppercase\expandafter{\romannumeral2}] doublets across all MaNGA spaxels. A total of 5,420 DPSs associated with 304 double-peaked narrow emission-line galaxies (DPGs) are identified, each DPG containing a minimum of 5 DPSs and being free from overlap with other galaxies. We find that DPSs can be categorized into three groups according to their central distance $r/R_e$ and the velocity difference $\Delta v$ between their two components: the inner low-$\Delta v$, inner high-$\Delta v$ and outer DPSs. By incorporating the physical characteristics of the DPGs into their DPSs, we demonstrate for the first time the existence of statistical correlations between barred DPGs and inner low-$\Delta v$ DPSs, AGN-hosting DPGs and inner high-$\Delta v$ DPSs, as well as tidal DPGs and outer DPSs.