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Main Authors: 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.
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.14936
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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