GA-NIFS: Witnessing the complex assembly of a massive star-forming system at $z=5.7$
| Autor: | Jones, Gareth C., Bunker, Andrew J., Telikova, Kseniia, Arribas, Santiago, Carniani, Stefano, Charlot, Stephane, D'Eugenio, Francesco, Maiolino, Roberto, Perna, Michele, Del Pino, Bruno Rodriguez, Ubler, Hannah, Willott, Chris, Aravena, Manuel, Boker, Torsten, Cresci, Giovanni, Curti, Mirko, Herrera-Camus, Rodrigo, Lamperti, Isabella, Parlanti, Eleonora, Perez-Gonzalez, Pablo G., Villanueva, Vicente |
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| Rok vydání: | 2024 |
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| Druh dokumentu: | Working Paper |
| Popis: | We present observations of the $z\sim5.7$ Lyman-break galaxy HZ10 with the JWST/NIRSpec IFU in high and low spectral resolution (G395H, $R\sim2700$ and PRISM, $R\sim100$, respectively), as part of the GA-NIFS program. By spatially resolving the source, we find evidence for three spatially and spectrally distinct regions of line emission along with one region of strong continuum emission, all within a projected distance of $<10$kpc. The R2700 data features strong detections in H$\beta$, [OIII]$\lambda\lambda4959{,}5007$, [NII]$\lambda\lambda6548{,}6584$, H$\alpha$, and [SII]$\lambda\lambda6716{,}6731$. The R100 data additionally contains a strong detection of the Ly$\alpha$ break, rest-UV continuum, and [OII]$\lambda\lambda3726{,}3729$. None of the detected lines present strong evidence for AGN excitation from line diagnostic diagrams, and no high-ionisation lines are detected. Using the detected lines, we constrain the electron density $\left( \rm \log_{10}\left( n_e / cm^{-3}\right)\sim2.5-3.3\right)$ and metallicity ($\sim0.5-0.7$ solar) in each component. Spaxel-by-spaxel fits of each cube reveal a strong east-west velocity gradient and significant line asymmetries (indicating tidal features or outflows). The western component features a very red UV slope ($\beta_{UV}\sim-1$) and significant H$\alpha$ emission, suggesting an evolved population and active star formation. From a comparison to high resolution [CII]$158\mu$m imaging obtained with the Atacama Large Millimetre/submillimetre Array (ALMA), we find that the continuum emitter is associated with a gas-poor stellar population. Altogether, these data suggest that HZ10 represents an ongoing merger, with a complex distribution of stars, gas, and dust $<1$Gyr after the Big Bang. Comment: 16 pages, 11 figures. Submitted to MNRAS |
| Databáze: | arXiv |
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