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| Auteurs principaux: | , |
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| Format: | Preprint |
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2023
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| Accès en ligne: | https://arxiv.org/abs/2307.06336 |
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| _version_ | 1866915238527369216 |
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| author | Langeroodi, Danial Hjorth, Jens |
| author_facet | Langeroodi, Danial Hjorth, Jens |
| contents | The empirical anti-correlation between gas-phase metallicity and star formation rate (SFR) at a fixed stellar mass, known as the fundamental metallicity relation (FMR), is commonly interpreted as an equilibrium state in the interplay between gas infall, enrichment, and gas removal. JWST/NIRSpec spectroscopy has shown a $z>3$ deviation from the local-universe FMR calibrations, suggesting that these galaxies are potentially caught out of equilibrium. To investigate this, we inferred the stellar population, nebular, and morphological properties of 427 galaxies at $3<z<10$ using uniformly reduced NIRSpec prism spectroscopy and NIRCam photometry. We consider morphology as a possible indicator of chemical enrichment stage. We find a mass-size relation already in place at $4<z<10$, with a normalization anti-correlated with redshift. The size-redshift anti-correlation depends on stellar mass: while the size of $M_*<10^8M_{\odot}$ galaxies strongly declines with redshift, $M_*>10^9M_{\odot}$ galaxies exhibit negligible redshift evolution. We also confirm the redshift evolution of the FMR: $z>3$ galaxies appear metal-deficient compared to expectations for their stellar mass and SFR according to the local-universe FMR. This offset grows with redshift. Metal deficiency is correlated with compactness: galaxies most offset from the average mass-size relation are also the most metal-poor for their stellar mass and SFR. We interpret this as a product of bursty star formation: compact galaxies exhibit elevated SFR surface densities, indicating that they are observed during burst episodes triggered by gas infall. While accretion of metal-poor gas has reduced their gas-phase metallicity by diluting the interstellar medium, they are observed prior to chemical yield release by newly formed massive stars. Simply, they are chemically out of equilibrium compared to the equilibrium state known as the FMR. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2307_06336 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Ultraviolet Compactness of High-Redshift Galaxies as a Tracer of Early-Stage Gas Infall, Bursty Star Formation, and Offset from the Fundamental Metallicity Relation Langeroodi, Danial Hjorth, Jens Astrophysics of Galaxies The empirical anti-correlation between gas-phase metallicity and star formation rate (SFR) at a fixed stellar mass, known as the fundamental metallicity relation (FMR), is commonly interpreted as an equilibrium state in the interplay between gas infall, enrichment, and gas removal. JWST/NIRSpec spectroscopy has shown a $z>3$ deviation from the local-universe FMR calibrations, suggesting that these galaxies are potentially caught out of equilibrium. To investigate this, we inferred the stellar population, nebular, and morphological properties of 427 galaxies at $3<z<10$ using uniformly reduced NIRSpec prism spectroscopy and NIRCam photometry. We consider morphology as a possible indicator of chemical enrichment stage. We find a mass-size relation already in place at $4<z<10$, with a normalization anti-correlated with redshift. The size-redshift anti-correlation depends on stellar mass: while the size of $M_*<10^8M_{\odot}$ galaxies strongly declines with redshift, $M_*>10^9M_{\odot}$ galaxies exhibit negligible redshift evolution. We also confirm the redshift evolution of the FMR: $z>3$ galaxies appear metal-deficient compared to expectations for their stellar mass and SFR according to the local-universe FMR. This offset grows with redshift. Metal deficiency is correlated with compactness: galaxies most offset from the average mass-size relation are also the most metal-poor for their stellar mass and SFR. We interpret this as a product of bursty star formation: compact galaxies exhibit elevated SFR surface densities, indicating that they are observed during burst episodes triggered by gas infall. While accretion of metal-poor gas has reduced their gas-phase metallicity by diluting the interstellar medium, they are observed prior to chemical yield release by newly formed massive stars. Simply, they are chemically out of equilibrium compared to the equilibrium state known as the FMR. |
| title | Ultraviolet Compactness of High-Redshift Galaxies as a Tracer of Early-Stage Gas Infall, Bursty Star Formation, and Offset from the Fundamental Metallicity Relation |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2307.06336 |