A Triple AGN in the NGC 7733-7734 Merging Group

TL;DR

This study identifies a rare triple AGN system in the NGC 7733-7734 merging group, revealing complex nuclear activity and ionization mechanisms through multi-wavelength observations and spectral analysis.

Contribution

First detection of a triple AGN system in a merging galaxy group using integral field spectroscopy and multi-wavelength data analysis.

Findings

NGC 7733 and NGC 7734 host Seyfert and LINER AGN activity.

Evidence of a third Seyfert-like component indicating a triple AGN system.

Detection of an Extended Narrow-line Region (ENLR) associated with NGC 7733.

Abstract

Context: Galaxy interactions and mergers can lead to supermassive black hole (SMBH) binaries which become active galactic nuclei (AGN) pairs when the SMBHs start accreting mass. If there is a third galaxy involved in the interaction, then a triple AGN system can form. Aims: Our goal is to investigate the nature of the nuclear emission from the galaxies in the interacting pair NGC\,7733--NGC\,7734 using archival VLT/MUSE Integral field spectrograph data and study its relation to the stellar mass distribution traced by near-infrared (NIR) observations from the South African Astronomical Observatory (SAAO). Methods:We conducted near-infrared observations using the SAAO and identified the morphological properties of bulges in each galaxy. We used MUSE data to obtain a set of ionized emission lines from each galaxy and studied the ionization mechanism. We also examined the relation of the galaxy pair with any nearby companions with Far-UV observations using the UVIT. Conclusions: The emission line analysis from the central regions of NGC\,7733 and NGC\,7734 show Seyfert and LINER type AGN activity. The galaxy pair NGC\,7733--34 also shows evidence of a third component, which has Seyfert-like emission. Hence, the galaxy pair NGC\,7733--34 forms a triple AGN system. We also detected an Extended Narrow-line region (ENLR) associated with the nucleus of NGC\,7733.