Kinematic properties of the dual AGN system J0038+4128 based on long-slit spectroscopy

TL;DR

This paper presents long-slit spectroscopic analysis of the dual AGN system J0038+4128, revealing co-rotating gaseous and stellar disks, and identifying active star-forming regions, providing insights into galaxy and black hole co-evolution during mergers.

Contribution

First spectroscopic study of J0038+4128 confirming co-rotating gas and stellar disks and identifying star-forming knots in a dual AGN system.

Findings

Average LOS velocity between nuclei is about 150 km/s.

Gaseous and stellar disks are co-rotating.

Multiple star-forming regions detected around nuclei.

Abstract

The study of kiloparsec-scale dual active galactic nuclei (AGN) will provide important clues to understand the co-evolution between the host galaxies and their central supermassive black holes undergoing a merging process. We present long-slit spectroscopy of the J0038$+$4128, a kiloparsec-scale dual AGN candidate discovered by Huang et al. recently, using the Yunnan Faint Object Spectrograph and Camera (YFOSC) mounted on Li-Jiang 2.4-m telescope at Yunnan observatories. From the long-slit spectra, we find that the average relative line-of-sight (LOS) velocity between the two nuclei (J0038$+$4128N and J0038$+$4128S) is about 150 km s$^{-1}$. The LOS velocities of the emission lines from the gas ionized by the nuclei activities and of the absorption lines from stars governed by the host galaxies for different regions of the J0038$+$4128 exhibit the same trend. The same velocities trend indicates that the gaseous disks are co-rotating with the stellar disks in this ongoing merge system. We also find several knots/giant HII regions scattered around the two nuclei with strong star formation revealed by the observed line ratios from the spectra. Those regions are also detected clearly in HST $F336W/U$-band and HST $F555W/V$-band images.