Episodic Feedback in Triple Active Galactic Nucleus Candidate SDSS J0849+1114 Revealed by Extended Ionized Gas

Abstract Galaxy mergers funnel gas toward the nuclei, igniting starbursts and active galactic nuclei (AGNs). The AGN feedback can reshape the host galaxy and regulate both star formation and supermassive black hole accretion. Using Very Large Telescope/MUSE integral-field spectroscopy, we conduct a spatially resolved study of the triple-AGN candidate SDSS J0849+1114. Extended ionized gas structures (&gt;10 kpc from nucleus A) primarily associated with tidal tails are detected. Meanwhile, two distinct ionized gas outflows are revealed. One extends over &gt;5 kpc around nuclei A with a kinetic power of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mover accent="true"> <mml:mrow> <mml:mi>E</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>̇</mml:mo> </mml:mrow> </mml:mover> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">out</mml:mi> <mml:mo>,</mml:mo> <mml:mi mathvariant="normal">A</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>3.0</mml:mn> <mml:mo>×</mml:mo> <mml:mn>1</mml:mn> <mml:msup> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>42</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">erg</mml:mi> <mml:mspace width="0.25em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> , which might be driven by the radio jet. The other outflow extends ∼5.9 kpc around nucleus C, with a kinetic power of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mover accent="true"> <mml:mrow> <mml:mi>E</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>̇</mml:mo> </mml:mrow> </mml:mover> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">out</mml:mi> <mml:mo>,</mml:mo> <mml:mi mathvariant="normal">C</mml:mi> </mml:mrow> </mml:msub> </mml:math> = 2.0 × 10 40 erg s −1 . High [O iii ]/H α and [N ii ]/H α ratios in the tidal gas require that nucleus A radiated at a high accretion rate with L A,bol ∼ 0.1–0.5 L Edd,A at least ∼3–×10 4 yr ago, 20–100 times brighter than today. Combined with multiwavelength constraints, we find evidence for episodic AGN feedback that expelled circumnuclear gas and rapidly quenched accretion. This triple AGN candidate demonstrates how AGN feedback can self-regulate black hole growth and impact hosts during mergers.