Exploring Spatially-Resolved Metallicities, Dynamics and Outflows in Low-Mass Galaxies at $z \sim 7.6$
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| Auteurs principaux: | , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| author | Ivey, L. R. Scholtz, J. Danhaive, A. L. Koudmani, S. Jones, G. C. Maiolino, R. Curti, M. D'Eugenio, F. Tacchella, S. Baker, W. M. Arribas, S. Charlot, S. Eisenstein, D. Ji, Z. Koller, M. Laporte, N. Puskás, D. Robertson, B. Sijacki, D. Trussler, J. A. A. Witten, C. |
| author_facet | Ivey, L. R. Scholtz, J. Danhaive, A. L. Koudmani, S. Jones, G. C. Maiolino, R. Curti, M. D'Eugenio, F. Tacchella, S. Baker, W. M. Arribas, S. Charlot, S. Eisenstein, D. Ji, Z. Koller, M. Laporte, N. Puskás, D. Robertson, B. Sijacki, D. Trussler, J. A. A. Witten, C. |
| contents | A majority of JWST/NIRSpec/IFU studies at high redshifts to date have focused on UV-bright or massive objects, while our understanding of low-mass galaxies at early cosmic times remains limited. In this work, we present NIRSpec/IFS high-resolution observations of two low-mass ($M_* < 10^9 \ M_\odot$), low-metallicity ($[12 + \log(\text{O/H})] < 8$) galaxies at $z \sim 7.66$, one of which we identify as hosting a Type-II AGN. We measure flat strong-line metallicity gradients, suggestive of ISM redistribution by outflows or past merging, but also identify tension with the direct-$T_\text{e}$ metallicity gradient in one galaxy. We measure $v_\text{rot}/σ< 1$ in both galaxies, consistent with observations of lower rotational support at early cosmic times. We identify broad kinematical components decoupled from galactic rotation with velocities of $\sim 250 - 500 \ \text{km} \ \text{s}^{-1}$ and argue these components trace outflows, for which we infer outflow rates of $\sim 8 - 14 \ M_\odot \ \text{yr}^{-1}$ with $v_\text{out}/v_\text{esc} \sim 1$. We compare our findings to results from the new large-volume AESOPICA simulations, which fully incorporate different models of black hole growth and AGN feedback. We find that our observational results of $v_\text{out}/v_\text{esc}$ are consistent with the simulated dwarf AGN population, hinting AGN-driven feedback may contribute to quenching both in our systems and in a wider population of low-mass galaxies in the early Universe. This novel study illustrates the necessity of deep IFU observations to decompose the complex kinematics and morphology of high-$z$ galaxies, trace outflows, and constrain the effect of feedback in the early Universe. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_14936 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Exploring Spatially-Resolved Metallicities, Dynamics and Outflows in Low-Mass Galaxies at $z \sim 7.6$ Ivey, L. R. Scholtz, J. Danhaive, A. L. Koudmani, S. Jones, G. C. Maiolino, R. Curti, M. D'Eugenio, F. Tacchella, S. Baker, W. M. Arribas, S. Charlot, S. Eisenstein, D. Ji, Z. Koller, M. Laporte, N. Puskás, D. Robertson, B. Sijacki, D. Trussler, J. A. A. Witten, C. Astrophysics of Galaxies A majority of JWST/NIRSpec/IFU studies at high redshifts to date have focused on UV-bright or massive objects, while our understanding of low-mass galaxies at early cosmic times remains limited. In this work, we present NIRSpec/IFS high-resolution observations of two low-mass ($M_* < 10^9 \ M_\odot$), low-metallicity ($[12 + \log(\text{O/H})] < 8$) galaxies at $z \sim 7.66$, one of which we identify as hosting a Type-II AGN. We measure flat strong-line metallicity gradients, suggestive of ISM redistribution by outflows or past merging, but also identify tension with the direct-$T_\text{e}$ metallicity gradient in one galaxy. We measure $v_\text{rot}/σ< 1$ in both galaxies, consistent with observations of lower rotational support at early cosmic times. We identify broad kinematical components decoupled from galactic rotation with velocities of $\sim 250 - 500 \ \text{km} \ \text{s}^{-1}$ and argue these components trace outflows, for which we infer outflow rates of $\sim 8 - 14 \ M_\odot \ \text{yr}^{-1}$ with $v_\text{out}/v_\text{esc} \sim 1$. We compare our findings to results from the new large-volume AESOPICA simulations, which fully incorporate different models of black hole growth and AGN feedback. We find that our observational results of $v_\text{out}/v_\text{esc}$ are consistent with the simulated dwarf AGN population, hinting AGN-driven feedback may contribute to quenching both in our systems and in a wider population of low-mass galaxies in the early Universe. This novel study illustrates the necessity of deep IFU observations to decompose the complex kinematics and morphology of high-$z$ galaxies, trace outflows, and constrain the effect of feedback in the early Universe. |
| title | Exploring Spatially-Resolved Metallicities, Dynamics and Outflows in Low-Mass Galaxies at $z \sim 7.6$ |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2507.14936 |