Browsing by Author "König, S."

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    Searching for Compact Obscured Nuclei in Compton-thick Active Galactic Nuclei
    (Institute of Physics, 2025) Johnstone, Makoto A.; Privon, George C.; Barcos-Muñoz, Loreto; Evans, A. S.; Aalto, S.; Armus, Lee; Bauer, Franz Erik; Blecha L.; Gallagher, J. S.; König, S.; Ricci, Claudio; Treister, Ezequiel; Eibensteiner, Cosima; Emig, Kimberly L.; Green, Kara N.; Kunneriath, Devaky; Nagarajan-Swenson, Jaya; Saravia, Alejandro; Yoon, Ilsang
    Compact obscured nuclei (CONs) are heavily obscured infrared cores that have been found in local (ultra-)luminous infrared galaxies. They show bright emission from vibrationally excited rotational transitions of HCN, known as HCN-vib, and are thought to harbor Compton-thick (CT, NH ≥ 1024 cm−2) active galactic nuclei (AGNs) or extreme compact starbursts. We explore the potential evolutionary link between CONs and CT-AGNs by searching for CONs in hard-X-ray-confirmed CT-AGNs from the Great Observatories All-sky LIRG Survey (GOALS). Here, we present new Atacama Large Millimeter/submillimeter Array Band 6 observations that targeted HCN-vib emission in four hard-X-ray-confirmed CT-AGNs. We analyze these objects together with literature HCN-vib measurements of five additional hard-X-ray-confirmed CT-AGNs from the GOALS sample. We do not detect any CONs in this combined sample of nine CT-AGNs. We then explore a proposed evolutionary sequence in which CONs evolve into X-ray-detectable CT-AGNs once outflows and feedback reduce the column densities of the enshrouding gas. We find, however, no evidence of well-developed dense molecular outflows in the observed CT-AGNs. While this could suggest that CT-AGNs are not universally linked to CONs, it could also be explained by a short duty cycle for molecular outflows.