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| Main Authors: | , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2408.03982 |
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| _version_ | 1866914905316130816 |
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| author | D'Eugenio, Francesco Maiolino, Roberto Mahatma, Vijay H. Mazzolari, Giovanni Carniani, Stefano de Graaff, Anna Maseda, Michael V. Parlanti, Eleonora Bunker, Andrew J. Ji, Xihan Jones, Gareth C. Morganti, Raffaella Scholtz, Jan Tacchella, Sandro Tadhunter, Clive Übler, Hannah Venturi, Giacomo |
| author_facet | D'Eugenio, Francesco Maiolino, Roberto Mahatma, Vijay H. Mazzolari, Giovanni Carniani, Stefano de Graaff, Anna Maseda, Michael V. Parlanti, Eleonora Bunker, Andrew J. Ji, Xihan Jones, Gareth C. Morganti, Raffaella Scholtz, Jan Tacchella, Sandro Tadhunter, Clive Übler, Hannah Venturi, Giacomo |
| contents | We present NIRSpec/MSA observations from the JWST large-area survey WIDE, targeting the rest-frame UV-optical spectrum of Ulema, a radio-AGN host at redshift z=4.6348. The low-resolution prism spectrum displays high equivalent width nebular emission, with remarkably high ratios of low-ionisation species of oxygen, nitrogen and sulphur, relative to hydrogen; auroral O$^+$ emission is clearly detected, possibly also C$^+$. From the high-resolution grating spectrum, we measure a gas velocity dispersion $σ$~400 km s$^{-1}$, broad enough to rule out star-forming gas in equilibrium in the gravitational potential of the galaxy. Emission-line ratio diagnostics suggest that the nebular emission is due to a shock which ran out of pre-shock gas. To infer the physical properties of the system, we model simultaneously the galaxy spectral energy distribution (SED) and shock-driven line emission under a Bayesian framework. We find a relatively low-mass, star-forming system (M* = 1.4$\times$10^{10} M$_\odot$, SFR = 70 M$_\odot$ yr$^{-1}$), where shock-driven emission contributes 50 per cent to the total H$β$ luminosity. The nebular metallicity is near solar - three times higher than that predicted by the mass-metallicity relation at z=4.6, possibly related to fast-paced chemical evolution near the galaxy nucleus. We find no evidence for a recent decline in the SFR of the galaxy, meaning that, already at this early epoch, fast radio-mode AGN feedback was poorly coupled with the bulk of the star-forming gas; therefore, most of the feedback energy must end up in the galaxy halo, setting the stage for future quenching. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2408_03982 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | JWST/NIRSpec WIDE survey: a z=4.6 low-mass star-forming galaxy hosting a jet-driven shock with low ionisation and solar metallicity D'Eugenio, Francesco Maiolino, Roberto Mahatma, Vijay H. Mazzolari, Giovanni Carniani, Stefano de Graaff, Anna Maseda, Michael V. Parlanti, Eleonora Bunker, Andrew J. Ji, Xihan Jones, Gareth C. Morganti, Raffaella Scholtz, Jan Tacchella, Sandro Tadhunter, Clive Übler, Hannah Venturi, Giacomo Astrophysics of Galaxies We present NIRSpec/MSA observations from the JWST large-area survey WIDE, targeting the rest-frame UV-optical spectrum of Ulema, a radio-AGN host at redshift z=4.6348. The low-resolution prism spectrum displays high equivalent width nebular emission, with remarkably high ratios of low-ionisation species of oxygen, nitrogen and sulphur, relative to hydrogen; auroral O$^+$ emission is clearly detected, possibly also C$^+$. From the high-resolution grating spectrum, we measure a gas velocity dispersion $σ$~400 km s$^{-1}$, broad enough to rule out star-forming gas in equilibrium in the gravitational potential of the galaxy. Emission-line ratio diagnostics suggest that the nebular emission is due to a shock which ran out of pre-shock gas. To infer the physical properties of the system, we model simultaneously the galaxy spectral energy distribution (SED) and shock-driven line emission under a Bayesian framework. We find a relatively low-mass, star-forming system (M* = 1.4$\times$10^{10} M$_\odot$, SFR = 70 M$_\odot$ yr$^{-1}$), where shock-driven emission contributes 50 per cent to the total H$β$ luminosity. The nebular metallicity is near solar - three times higher than that predicted by the mass-metallicity relation at z=4.6, possibly related to fast-paced chemical evolution near the galaxy nucleus. We find no evidence for a recent decline in the SFR of the galaxy, meaning that, already at this early epoch, fast radio-mode AGN feedback was poorly coupled with the bulk of the star-forming gas; therefore, most of the feedback energy must end up in the galaxy halo, setting the stage for future quenching. |
| title | JWST/NIRSpec WIDE survey: a z=4.6 low-mass star-forming galaxy hosting a jet-driven shock with low ionisation and solar metallicity |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2408.03982 |