%ALi, Wenhao%ANair, Preethi%AIrwin, Jimmy%AEllison, Sara%ASatyapal, Shobita%ADrory, Niv%AJones, Amy%AKeel, William%AMasters, Karen%AStark, David%ARyan, Russell%AMukundan, Kavya%BJournal Name: The Astrophysical Journal; Journal Volume: 944; Journal Issue: 2; Related Information: CHORUS Timestamp: 2024-01-16 17:35:46 %D2023%IDOI PREFIX: 10.3847 %JJournal Name: The Astrophysical Journal; Journal Volume: 944; Journal Issue: 2; Related Information: CHORUS Timestamp: 2024-01-16 17:35:46 %K %MOSTI ID: 10398380 %PMedium: X; Size: Article No. 168 %TA Multiwavelength Study of Active Galactic Nuclei in Post-merger Remnants %XAbstract

We investigate the role of galaxy mergers in triggering active galactic nuclei (AGN) in the nearby universe. Our analysis is based on a sample of 79 post-merger remnant galaxies with deep X-ray observations from Chandra/XMM-Newton capable of detecting a low-luminosity AGN of ≥1040.5erg s−1. This sample is derived from a visually classified, volume-limited sample of 807 post-mergers identified in the Sloan Digital Sky Survey Data Release 14 with logM*/M≥ 10.5 and 0.02 ≤z≤ 0.06. We find that the X-ray AGN fraction in this sample is 55.7% ± 5.6% compared to 23.6% ± 2.8% for a mass- and redshift-matched noninteracting control sample. The multiwavelength AGN fraction (identified as an AGN in one of X-ray, IR, radio or optical diagnostics) for post-mergers is 76.6% ± 4.8% compared to 39.1% ± 3.2% for controls. Thus post-mergers exhibit a high overall AGN fraction with an excess between 2 and 4 depending on the AGN diagnostics used. In addition, we find most optical, IR, and radio AGN are also identified as X-ray AGN while a large fraction of X-ray AGN are not identified in any other diagnostic. This highlights the importance of deep X-ray imaging to identify AGN. We find that the X-ray AGN fraction of post-mergers is independent of the stellar mass above logM*/M≥ 10.5 unlike the trend seen in control galaxies. Overall, our results show that post-merger galaxies are a good tracer of the merger–AGN connection and strongly support the theoretical expectations that mergers trigger AGN.

%0Journal Article