Evidence for environmental effects in the $z\,{=}\,4.3$ protocluster core SPT2349$-$56
| Autor: | Hughes, Chayce, Hill, Ryley, Chapman, Scott, Aravena, Manuel, Archipley, Melanie, Dike, Veronica J., Gonzalez, Anthony, Greve, Thomas R., Gururajan, Gayathri, Hayward, Chris, Phadke, Kedar, Reuter, Cassie, Spilker, Justin, Sulzenauer, Nikolaus, Vieira, Joaquin D., Vizgan, David, Wang, George, Weiss, Axel, Zhou, Dazhi |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | We present ALMA observations of the [CI] 492 and 806$\,$GHz fine-structure lines in 25 dusty star-forming galaxies (DSFGs) at $z\,{=}\,4.3$ in the core of the SPT2349$-$56 protocluster. The protocluster galaxies exhibit a median $L^\prime_{[\text{CI}](2-1)}/L^\prime_{[\text{CI}](1-0)}$ ratio of 0.94 with an interquartile range of 0.81-1.24. These ratios are markedly different to those observed in DSFGs in the field (across a comparable redshift and 850$\,\mu$m flux density range), where the median is 0.55 with an interquartile range of 0.50-0.76, and we show that this difference is driven by an excess of [CI](2-1) in the protocluster galaxies for a given 850$\,\mu$m flux density. We estimate gas excitation temperatures of $T_{\rm ex}\,{=}\,59.1^{+8.1}_{-6.8}\,$K for our protocluster sample and $T_{\rm ex}\,{=}\,33.9^{+2.4}_{-2.2}\,$K for the field sample. Our main interpretation of this result is that the protocluster galaxies have had their cold gas driven to their cores via close-by interactions within the dense environment, leading to an overall increase in the average gas density and excitation temperature, and an elevated [CI](2-1) luminosity-to-far-infrared luminosity ratio. Comment: Submitted to ApJL |
| Databáze: | arXiv |
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