SDSS-IV MaNGA: Physical Origins of Double-Peaked Narrow Emission-Line Spaxels in Barred Galaxies

TL;DR

This study investigates the origins of double-peaked emission lines in barred galaxies, finding that they mainly result from the convolution of the PSF with fast-rotating nuclear rings induced by bars.

Contribution

It provides the first detailed analysis linking double-peaked emission lines to bar-induced nuclear rings using dynamical modeling and MaNGA data.

Findings

Significant correlation between nuclear ring radii and DPS maximum distances.

Marginal correlation between ring rotational velocities and DPS velocity differences.

Evidence supports DPS origin from PSF convolution with nuclear rings.

Abstract

The physical origins of double-peaked narrow emission-line spaxels (DPSs) in barred galaxies are explored through the analysis of a sample of 72 barred double-peaked emission-line galaxies (DPGs) extracted from the MaNGA dataset. In this study, we examine two potential scenarios: the gas inflow along the bar and the formation of a bar-induced gaseous nuclear ring. By applying a classical galactic dynamics model, we calculate the radii and rotational velocities of the nuclear rings for all barred DPGs, and compare them with the observed properties of their DPSs. Our analysis reveals a significant correlation between the predicted radii of the nuclear rings and the maximum centric distances of the DPSs, as well as a marginal correlation between the predicted rotational velocities of the nuclear rings and the observed maximum velocity differences of the DPSs. These findings provide strong evidence to support the hypothesis that the DPSs of a barred DPG in MaNGA primarily originate from the convolution of the PSF effect with its bar-induced fast-rotating gaseous nuclear ring.