Browsing by Author "Gallagher, J. S."
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- ItemHidden molecular outflow in the LIRG Zw 049.057(2018) Falstad, N.; Aalto, S.; Mangum, J. G.; Costagliola, F.; Gallagher, J. S.; Gonzalez-Alfonso, E.; Sakamoto, K.; Konig, S.; Muller, S.; Evans, A. S.; Privon, G. C.Context. Feedback in the form of mass outflows driven by star formation or active galactic nuclei is a key component of galaxy evolution. The luminous infrared galaxy Zw 049.057 harbours a compact obscured nucleus with a possible far-infrared signature of outflowing molecular gas. Due to the high optical depths at far-infrared wavelengths, however, the interpretation of the outflow signature is uncertain. At millimeter and radio wavelengths, the radiation is better able to penetrate the large columns of gas and dust responsible for the obscuration.
- ItemSearching 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, IlsangCompact 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.