De Breuck, CarlosWeiß, AxelBéthermin, MatthieuCunningham, DanielApostolovski, YordankaAravena, ManuelArchipley, MelanieChapman, ScottChen, Chian-ChouFu, JianyangJarugula, SreevaniMalkan, Matt2024-06-252024-06-252019-11-01Astronomy and Astrophysics Volume 631 1 November 2019 Article number A1670004-6361https://repositorio.unab.cl/handle/ria/57970Indexación: Scopus.We present a study of six far-infrared fine structure lines in the z = 4.225 lensed dusty star-forming galaxy SPT 0418-47 to probe the physical conditions of its interstellar medium (ISM). In particular, we report Atacama Pathfinder EXperiment (APEX) detections of the [OI] 145 μm and [OIII] 88 μm lines and Atacama Compact Array (ACA) detections of the [NII] 122 and 205 μm lines. The [OI] 145 μm/[CII] 158 μm line ratio is ∼5× higher compared to the average of local galaxies. We interpret this as evidence that the ISM is dominated by photo-dissociation regions with high gas densities. The line ratios, and in particular those of [OIII] 88 μm and [NII] 122 μm imply that the ISM in SPT 0418-47 is already chemically enriched to nearly solar metallicity. While the strong gravitational amplification was required to detect these lines with APEX, larger samples can be observed with the Atacama Large Millimeter/submillimeter Array (ALMA), and should allow observers to determine if the dense, solar metallicity ISM is common among these highly star-forming galaxies.en-USGalaxies: high-redshiftGalaxies: ISMSubmillimeter: galaxiesSubmillimeter: ISMArtículoATRIBUCIÓN 4.0 INTERNACIONAL10.1051/0004-6361/201936169