_version_ 1866915314328928256
author Jones, Gareth C.
Bunker, Andrew J.
Telikova, Kseniia
Arribas, Santiago
Carniani, Stefano
Charlot, Stephane
D'Eugenio, Francesco
Maiolino, Roberto
Perna, Michele
Del Pino, Bruno Rodríguez
Übler, Hannah
Willott, Chris
Aravena, Manuel
Böker, Torsten
Cresci, Giovanni
Curti, Mirko
González-López, Jorge
Herrera-Camus, Rodrigo
Lamperti, Isabella
Parlanti, Eleonora
Perez-Gonzalez, Pablo G.
Villanueva, Vicente
author_facet Jones, Gareth C.
Bunker, Andrew J.
Telikova, Kseniia
Arribas, Santiago
Carniani, Stefano
Charlot, Stephane
D'Eugenio, Francesco
Maiolino, Roberto
Perna, Michele
Del Pino, Bruno Rodríguez
Übler, Hannah
Willott, Chris
Aravena, Manuel
Böker, Torsten
Cresci, Giovanni
Curti, Mirko
González-López, Jorge
Herrera-Camus, Rodrigo
Lamperti, Isabella
Parlanti, Eleonora
Perez-Gonzalez, Pablo G.
Villanueva, Vicente
contents We present observations of the $z\sim5.7$ Lyman-break galaxy HZ10 with the JWST/NIRSpec IFU in high and low spectral resolution (G395H, spectral resolving power $R\sim2700$ and PRISM, $R\sim100$, respectively), as part of the GA-NIFS program. By spatially resolving the source (spatial resolution $\sim0.15''$ or $\sim0.9$kpc), we find 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$β$, [OIII]$λ\lambda4959{,}5007$, [NII]$λ\lambda6548{,}6584$, H$α$, and [SII]$λ\lambda6716{,}6731$. The R100 data additionally contains a strong detection of the Ly$α$ break, rest-frame UV and optical continuum, and [OII]$λ\lambda3726{,}3729$. 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 $\left( \rm \log_{10}\left( n_e / cm^{-3}\right)\sim 3\right)$ and metallicity ($\sim0.5-0.7$ solar) in each component. Spaxel-by-spaxel fits reveal a strong east-west velocity gradient and significant line asymmetries (possibly indicating tidal features or outflows). The western component features a very red UV slope ($β_{\rm UV}\sim-0.9$) and significant H$α$ emission, suggesting an evolved population and active star formation. A comparison to high resolution ($\sim0.3''$ or $\sim1.8$kpc) [CII]$158μ$m imaging obtained with the Atacama Large Millimetre/submillimetre Array (ALMA) reveals areas of dust obscuration. 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.
format Preprint
id arxiv_https___arxiv_org_abs_2405_12955
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle GA-NIFS: Witnessing the complex assembly of a star-forming system at $z=5.7$
Jones, Gareth C.
Bunker, Andrew J.
Telikova, Kseniia
Arribas, Santiago
Carniani, Stefano
Charlot, Stephane
D'Eugenio, Francesco
Maiolino, Roberto
Perna, Michele
Del Pino, Bruno Rodríguez
Übler, Hannah
Willott, Chris
Aravena, Manuel
Böker, Torsten
Cresci, Giovanni
Curti, Mirko
González-López, Jorge
Herrera-Camus, Rodrigo
Lamperti, Isabella
Parlanti, Eleonora
Perez-Gonzalez, Pablo G.
Villanueva, Vicente
Astrophysics of Galaxies
We present observations of the $z\sim5.7$ Lyman-break galaxy HZ10 with the JWST/NIRSpec IFU in high and low spectral resolution (G395H, spectral resolving power $R\sim2700$ and PRISM, $R\sim100$, respectively), as part of the GA-NIFS program. By spatially resolving the source (spatial resolution $\sim0.15''$ or $\sim0.9$kpc), we find 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$β$, [OIII]$λ\lambda4959{,}5007$, [NII]$λ\lambda6548{,}6584$, H$α$, and [SII]$λ\lambda6716{,}6731$. The R100 data additionally contains a strong detection of the Ly$α$ break, rest-frame UV and optical continuum, and [OII]$λ\lambda3726{,}3729$. 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 $\left( \rm \log_{10}\left( n_e / cm^{-3}\right)\sim 3\right)$ and metallicity ($\sim0.5-0.7$ solar) in each component. Spaxel-by-spaxel fits reveal a strong east-west velocity gradient and significant line asymmetries (possibly indicating tidal features or outflows). The western component features a very red UV slope ($β_{\rm UV}\sim-0.9$) and significant H$α$ emission, suggesting an evolved population and active star formation. A comparison to high resolution ($\sim0.3''$ or $\sim1.8$kpc) [CII]$158μ$m imaging obtained with the Atacama Large Millimetre/submillimetre Array (ALMA) reveals areas of dust obscuration. 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.
title GA-NIFS: Witnessing the complex assembly of a star-forming system at $z=5.7$
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2405.12955