RIOJA. JWST and ALMA unveil the inhomogeneous and complex ISM structure in a star-forming galaxy at $z=6.81$
Fuente:
arXiv
Salvato in:
| Autori principali: | , , , , , , , , , , , , , , , , , , , , , , , |
|---|---|
| Natura: | Preprint |
| Pubblicazione: |
2025
|
| Soggetti: | |
| Accesso online: | |
| Tags: |
Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
|
| _version_ | 1866908528385458176 |
|---|---|
| author | Usui, Mitsutaka Mawatari, Ken Álvarez-Márquez, Javier Hashimoto, Takuya Sugahara, Yuma Marques-Chaves, Rui Inoue, Akio K. Colina, Luis Arribas, Santiago Blanco-Prieto, Carmen Nakazato, Yurina Yoshida, Naoki Bakx, Tom J. L. C. Ceverino, Daniel Costantin, Luca Gómez, Alejandro Crespo Hagimoto, Masato Matsuo, Hiroshi Osone, Wataru Ren, Yi W. Fudamoto, Yoshinobu Hashigaya, Takeshi Pereira-Santaella, Miguel Tamura, Yoichi |
| author_facet | Usui, Mitsutaka Mawatari, Ken Álvarez-Márquez, Javier Hashimoto, Takuya Sugahara, Yuma Marques-Chaves, Rui Inoue, Akio K. Colina, Luis Arribas, Santiago Blanco-Prieto, Carmen Nakazato, Yurina Yoshida, Naoki Bakx, Tom J. L. C. Ceverino, Daniel Costantin, Luca Gómez, Alejandro Crespo Hagimoto, Masato Matsuo, Hiroshi Osone, Wataru Ren, Yi W. Fudamoto, Yoshinobu Hashigaya, Takeshi Pereira-Santaella, Miguel Tamura, Yoichi |
| contents | We report the discovery of a complex, density-stratified interstellar medium (ISM) in the star-forming galaxy COS-2987 at $z = 6.81$, revealed by the unprecedented synergy between JWST/NIRSpec IFS and ALMA observations. These observations detect key emission lines, including \oii~$λλ$~3727, 3730, \oiii~4364, \oiii~$λλ$~4960, 5008, \oiii\ 88 \micron, as well as H$α$ and H$β$. JWST spectroscopy alone indicates ISM properties that are typical for galaxies at $z\sim7$. These include low dust extinction ($A_{\rm V} \approx 0.14$ mag), moderate electron density ($n_{\rm e} \approx 500$~cm$^{-3}$), and low gas-phase metallicity ($\sim10\%$). However, the strong far-infrared \oiii\ 88 \micron\ emission detected by ALMA cannot be explained by a single-component ionized medium with uniform electron density and temperature. Instead, a two-component ISM model, comprising compact, high-temperature, high-density gas components ($T_e \approx 26,000$\,K; $n_e \approx 600~\mathrm{cm}^{-3}$) and an extended, cooler, lower-density component ($T_e \approx 8,000$\,K; $n_e \approx 50~\mathrm{cm}^{-3}$), successfully reproduces the observed line ratios of \oiii~88~\micron/\oiii~5008~Å and \oiii~4364/\oiii~5008~Å, with a volume ratio of 1 : 300 between the two components. Our results demonstrate that JWST alone probes only a fraction of the ISM and highlight the critical importance of combining JWST and ALMA to reveal the density-stratified ISM of early galaxies. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_02054 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | RIOJA. JWST and ALMA unveil the inhomogeneous and complex ISM structure in a star-forming galaxy at $z=6.81$ Usui, Mitsutaka Mawatari, Ken Álvarez-Márquez, Javier Hashimoto, Takuya Sugahara, Yuma Marques-Chaves, Rui Inoue, Akio K. Colina, Luis Arribas, Santiago Blanco-Prieto, Carmen Nakazato, Yurina Yoshida, Naoki Bakx, Tom J. L. C. Ceverino, Daniel Costantin, Luca Gómez, Alejandro Crespo Hagimoto, Masato Matsuo, Hiroshi Osone, Wataru Ren, Yi W. Fudamoto, Yoshinobu Hashigaya, Takeshi Pereira-Santaella, Miguel Tamura, Yoichi Astrophysics of Galaxies We report the discovery of a complex, density-stratified interstellar medium (ISM) in the star-forming galaxy COS-2987 at $z = 6.81$, revealed by the unprecedented synergy between JWST/NIRSpec IFS and ALMA observations. These observations detect key emission lines, including \oii~$λλ$~3727, 3730, \oiii~4364, \oiii~$λλ$~4960, 5008, \oiii\ 88 \micron, as well as H$α$ and H$β$. JWST spectroscopy alone indicates ISM properties that are typical for galaxies at $z\sim7$. These include low dust extinction ($A_{\rm V} \approx 0.14$ mag), moderate electron density ($n_{\rm e} \approx 500$~cm$^{-3}$), and low gas-phase metallicity ($\sim10\%$). However, the strong far-infrared \oiii\ 88 \micron\ emission detected by ALMA cannot be explained by a single-component ionized medium with uniform electron density and temperature. Instead, a two-component ISM model, comprising compact, high-temperature, high-density gas components ($T_e \approx 26,000$\,K; $n_e \approx 600~\mathrm{cm}^{-3}$) and an extended, cooler, lower-density component ($T_e \approx 8,000$\,K; $n_e \approx 50~\mathrm{cm}^{-3}$), successfully reproduces the observed line ratios of \oiii~88~\micron/\oiii~5008~Å and \oiii~4364/\oiii~5008~Å, with a volume ratio of 1 : 300 between the two components. Our results demonstrate that JWST alone probes only a fraction of the ISM and highlight the critical importance of combining JWST and ALMA to reveal the density-stratified ISM of early galaxies. |
| title | RIOJA. JWST and ALMA unveil the inhomogeneous and complex ISM structure in a star-forming galaxy at $z=6.81$ |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2507.02054 |