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Main Authors: Cao, Xiao, Chen, Yan-Mei, Shi, Yong, Wang, Junfeng, Zhou, Zhi-Jie, Bao, Min, Gu, Qiusheng, Moiseev, Alexei, Ho, Luis C., Wang, Lan, Zeng, Guangquan
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2502.01921
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author Cao, Xiao
Chen, Yan-Mei
Shi, Yong
Wang, Junfeng
Zhou, Zhi-Jie
Bao, Min
Gu, Qiusheng
Moiseev, Alexei
Ho, Luis C.
Wang, Lan
Zeng, Guangquan
author_facet Cao, Xiao
Chen, Yan-Mei
Shi, Yong
Wang, Junfeng
Zhou, Zhi-Jie
Bao, Min
Gu, Qiusheng
Moiseev, Alexei
Ho, Luis C.
Wang, Lan
Zeng, Guangquan
contents Dual active galactic nuclei (AGNs) with comparable masses are commonly witnessed among the major merged galaxies with interaction remnants. Considering almost every massive galaxy is associated with multiple dwarf satellites around it, minor mergers involving galaxies with disproportional stellar masses should be much more common than major mergers, which would naturally lead to black hole (BH) pairs with significantly different masses. However, dual AGNs generated by minor mergers involving one or two dwarf galaxies are exceptionally rare and understudied. Moreover, good estimates of the masses of both BHs are not yet available to test this idea. Here we report the evidence of a dual AGN candidate with mass ratio $\sim$7:1 located in an undisturbed disk galaxy. We identify the central BH with mass of $9.4 \times 10^6M_\odot$ from its radio emission as well as AGN-driven galactic-scale biconical outflows. The off-centered BH generates obvious broad and narrow emission-line regions, which gives us a robust estimation of a $1.3 \times 10^6M_\odot$ BH mass. We explore alternative scenarios for explaining the observational features of this system, including the complex gas kinematics triggered by central AGN activity and dust attenuation of the broad-line region of the central BH, finding that they failed to fully account for the kinematics of both the redshifted off-centered broad and narrow emission-line components.
format Preprint
id arxiv_https___arxiv_org_abs_2502_01921
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Dual Active Black Hole Candidate with Mass Ratio ~7:1 in a Disk Galaxy
Cao, Xiao
Chen, Yan-Mei
Shi, Yong
Wang, Junfeng
Zhou, Zhi-Jie
Bao, Min
Gu, Qiusheng
Moiseev, Alexei
Ho, Luis C.
Wang, Lan
Zeng, Guangquan
Astrophysics of Galaxies
Dual active galactic nuclei (AGNs) with comparable masses are commonly witnessed among the major merged galaxies with interaction remnants. Considering almost every massive galaxy is associated with multiple dwarf satellites around it, minor mergers involving galaxies with disproportional stellar masses should be much more common than major mergers, which would naturally lead to black hole (BH) pairs with significantly different masses. However, dual AGNs generated by minor mergers involving one or two dwarf galaxies are exceptionally rare and understudied. Moreover, good estimates of the masses of both BHs are not yet available to test this idea. Here we report the evidence of a dual AGN candidate with mass ratio $\sim$7:1 located in an undisturbed disk galaxy. We identify the central BH with mass of $9.4 \times 10^6M_\odot$ from its radio emission as well as AGN-driven galactic-scale biconical outflows. The off-centered BH generates obvious broad and narrow emission-line regions, which gives us a robust estimation of a $1.3 \times 10^6M_\odot$ BH mass. We explore alternative scenarios for explaining the observational features of this system, including the complex gas kinematics triggered by central AGN activity and dust attenuation of the broad-line region of the central BH, finding that they failed to fully account for the kinematics of both the redshifted off-centered broad and narrow emission-line components.
title A Dual Active Black Hole Candidate with Mass Ratio ~7:1 in a Disk Galaxy
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2502.01921