_version_ 1866911621414125568
author Bik, Arjan
Álvarez-Márquez, Javier
Gómez, Alejandro Crespo
Colina, Luis
Pérez-González, Pablo G.
Östlin, Göran
Prieto, Carmen Blanco
Melinder, Jens
Langeroodi, Danial
Wright, Gillian
Algera, Hiddo S. B.
Boogaard, Leindert A.
Caputi, Karina
Gillman, Steven
Greve, Thomas
Hjorth, Jens
Iani, Edoardo
Kendrew, Sarah
Ortega, Alvaro Labiano
Perna, Michele
Jimenez, Carlota Prieto
Pye, John
Rinaldi, Pierluigi
van der Werf, Paul
Walter, Fabian
Peißker, Florian
Eckart, Andreas
Henning, Thomas
Güdel, Manuel
author_facet Bik, Arjan
Álvarez-Márquez, Javier
Gómez, Alejandro Crespo
Colina, Luis
Pérez-González, Pablo G.
Östlin, Göran
Prieto, Carmen Blanco
Melinder, Jens
Langeroodi, Danial
Wright, Gillian
Algera, Hiddo S. B.
Boogaard, Leindert A.
Caputi, Karina
Gillman, Steven
Greve, Thomas
Hjorth, Jens
Iani, Edoardo
Kendrew, Sarah
Ortega, Alvaro Labiano
Perna, Michele
Jimenez, Carlota Prieto
Pye, John
Rinaldi, Pierluigi
van der Werf, Paul
Walter, Fabian
Peißker, Florian
Eckart, Andreas
Henning, Thomas
Güdel, Manuel
contents Studying the interstellar medium (ISM) in merging high-redshift galaxies is crucial for understanding early galaxy assembly, star formation, and black hole growth, predicted by hierarchical $Λ$CDM models. Deep imaging and spatially resolved spectroscopy with JWST enable unprecedented insight into these processes, even for galaxies in the Epoch of Reionization. We present NIRSpec and MIRI integral field spectroscopy and MIRI imaging of the merging galaxy Gz9p3 at z=9.3 of the UV and optical rest-frame showing a clumpy morphology in the continuum as well as line emission covering the entire galaxy over a range of 5 kpc from the central clump to the tail region. We analyze the integrated spectrum as well as different apertures in the galaxy allowing a spatially resolved characterization of the ionized ISM of this galaxy. We compare our measurements with archival NIRCam imaging and ALMA data. We measure a total star formation rate of 13.4 $\pm$ 1.8 Msun yr$^{-1}$, a metallicity of 12+log(O/H) = 7.84 $\pm$ 0.05 and $ξ_{ion}$= 25.4 $\pm$ 0.1 erg$^{-1}$ Hz and a burstiness parameter of 0.9 $\pm$ 0.1 for the integrated spectrum. We find large spatial differences in these parameters between the central clump and the tail region. The optical [OIII] emission peaks in the main galaxy, the far-infrared [OIII] emission peaks towards the tail, indicating different physical conditions in the ISM of the tail and main galaxy. This study presents the spatially resolved ISM analyses of a galaxy at z>9, revealing nebular line emission and strong spatial variations in star formation, metallicity, physical conditions, and ionizing efficiency. The results indicate a recent, metal-poor starburst in a tail alongside a more evolved, enriched central clump with evidence for extreme excitation. This demonstrates the power of spatially resolved JWST spectroscopy of galaxies in the Epoch of Reionization.
format Preprint
id arxiv_https___arxiv_org_abs_2604_22460
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Spatially resolved metallicity and ionization in the merging system Gz9p3 at z=9.3
Bik, Arjan
Álvarez-Márquez, Javier
Gómez, Alejandro Crespo
Colina, Luis
Pérez-González, Pablo G.
Östlin, Göran
Prieto, Carmen Blanco
Melinder, Jens
Langeroodi, Danial
Wright, Gillian
Algera, Hiddo S. B.
Boogaard, Leindert A.
Caputi, Karina
Gillman, Steven
Greve, Thomas
Hjorth, Jens
Iani, Edoardo
Kendrew, Sarah
Ortega, Alvaro Labiano
Perna, Michele
Jimenez, Carlota Prieto
Pye, John
Rinaldi, Pierluigi
van der Werf, Paul
Walter, Fabian
Peißker, Florian
Eckart, Andreas
Henning, Thomas
Güdel, Manuel
Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
Studying the interstellar medium (ISM) in merging high-redshift galaxies is crucial for understanding early galaxy assembly, star formation, and black hole growth, predicted by hierarchical $Λ$CDM models. Deep imaging and spatially resolved spectroscopy with JWST enable unprecedented insight into these processes, even for galaxies in the Epoch of Reionization. We present NIRSpec and MIRI integral field spectroscopy and MIRI imaging of the merging galaxy Gz9p3 at z=9.3 of the UV and optical rest-frame showing a clumpy morphology in the continuum as well as line emission covering the entire galaxy over a range of 5 kpc from the central clump to the tail region. We analyze the integrated spectrum as well as different apertures in the galaxy allowing a spatially resolved characterization of the ionized ISM of this galaxy. We compare our measurements with archival NIRCam imaging and ALMA data. We measure a total star formation rate of 13.4 $\pm$ 1.8 Msun yr$^{-1}$, a metallicity of 12+log(O/H) = 7.84 $\pm$ 0.05 and $ξ_{ion}$= 25.4 $\pm$ 0.1 erg$^{-1}$ Hz and a burstiness parameter of 0.9 $\pm$ 0.1 for the integrated spectrum. We find large spatial differences in these parameters between the central clump and the tail region. The optical [OIII] emission peaks in the main galaxy, the far-infrared [OIII] emission peaks towards the tail, indicating different physical conditions in the ISM of the tail and main galaxy. This study presents the spatially resolved ISM analyses of a galaxy at z>9, revealing nebular line emission and strong spatial variations in star formation, metallicity, physical conditions, and ionizing efficiency. The results indicate a recent, metal-poor starburst in a tail alongside a more evolved, enriched central clump with evidence for extreme excitation. This demonstrates the power of spatially resolved JWST spectroscopy of galaxies in the Epoch of Reionization.
title Spatially resolved metallicity and ionization in the merging system Gz9p3 at z=9.3
topic Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2604.22460