Behind the dust veil: A panchromatic view of an optically dark galaxy at z=4.82
| Autor: | Sillassen, Nikolaj B., Jin, Shuowen, Magdis, Georgios E., Hodge, Jacqueline, Gobat, Raphael, Daddi, Emanuele, Knudsen, Kirsten, Finoguenov, Alexis, Schinnerer, Eva, Wang, Wei-Hao, Gao, Zhen-Kai, Weaver, John R., Algera, Hiddo, Andika, Irham T., Brinch, Malte, Chen, Chian-Chou, Cochrane, Rachel, Enia, Andrea, Faisst, Andreas, Gillman, Steven, Gomez-Guijarro, Carlos, Gozaliasl, Ghassem, Hayward, Chris, Kokorev, Vasily, Merchant, Maya, Rizzo, Francesca, Talia, Margherita, Valentino, Francesco, Blánquez-Sesé, David, Koekemoer, Anton M., Magnelli, Benjamin, Rich, Michael, Shuntov, Marko |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | Optically dark dusty star-forming galaxies (DSFGs) play an essential role in massive galaxy formation at early cosmic time, however their nature remains elusive. Here we present a detailed case study of all the baryonic components of a $z=4.821$ DSFG, XS55. Selected from the ultra-deep COSMOS-XS 3GHz map with a red SCUBA-2 450$\mu$m/850$\mu$m colour, XS55 was followed up with ALMA 3mm line scans and spectroscopically confirmed to be at $z=4.821$ via detections of the CO(5-4) and [CI](1-0) lines. JWST/NIRCam imaging reveals that XS55 is a F150W-dropout with red F277W/F444W colour, and a complex morphology: a compact central component embedded in an extended structure with a likely companion. XS55 is tentatively detected in X-rays with both Chandra and XMM-Newton, suggesting an active galactic nucleus (AGN) nature. By fitting a panchromatic SED spanning NIR to radio wavelengths, we revealed that XS55 is a massive main-sequence galaxy with a stellar mass of $M_\ast=(5\pm1)\times10^{10}\,{\rm M_\odot}$ and a star formation rate of ${\rm SFR}=540\pm177~{\rm M_\odot\,yr^{-1}}$. The dust of XS55 is optically thick in the far infrared (FIR) with a surprisingly cold dust temperature of $T_{\rm dust}=33\pm2\,{\rm K}$, making XS55 one of the coldest DSFGs at $z>4$ known to date. This work unveils the nature of a radio-selected F150W-dropout, suggesting the existence of a population of DSFGs hosting active black holes embedded in optically thick dust. Comment: 11 pages, 7 figures, accepted in Astronomy & Astrophysics |
| Databáze: | arXiv |
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