On bursty star formation during cosmological reionization -- influence on the metal and dust content of low-mass galaxies
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| Format: | Preprint |
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2025
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| _version_ | 1866908919792664576 |
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| author | Menon, Anand Balu, Sreedhar Power, Chris |
| author_facet | Menon, Anand Balu, Sreedhar Power, Chris |
| contents | Observations indicate that high-redshift galaxies undergo episodic star formation bursts, driving strong outflows that expel gas and suppress accretion. We investigate the consequences for metal and dust content of galaxies at $z \geq 5$ using our semi-analytical model, ASHVINI. We track gas-phase and stellar metallicities ($Z_{\rm g}, Z_\ast$) and dust mass (M$_{\rm d}$) in dark matter haloes spanning $M_{\rm halo} = 10^6$-$10^{11}$ $M_\odot$, comparing continuous and bursty star formation scenarios - which reflect underlying assumptions of instantaneous and delayed feedback - and we allow for metallicity-dependent feedback efficiency. Delayed feedback induces oscillations in $Z_{\rm g}$ and $Z_\ast$, with $Z_{\rm g}$ declining sharply at low stellar and halo masses; the mass scale of this decline increases toward lower redshift. Reionization introduces significant scatter in $Z_{\rm g}$, producing an upturn followed by rapid decline. Metallicity-dependent feedback moderates this decline at $ z=7 - 10$, flattening the $Z_{\rm g}$-mass relation to $\simeq 0.03$-$0.04\, Z_\odot$. Dust production tracks $Z_{\rm g}$ but is sensitive to burst history, causing delayed enrichment. Our results show that burst-driven feedback decouples $Z_{\rm g}$ and $Z_\ast$, imprints intrinsic scatter in mass-metallicity relations, and delays dust growth. These effects are strongest in low-mass halos ($M_{\rm halo} \sim 10^7 M_\odot$), where shallow potentials amplify the impact of feedback. Our results are consistent with recent hydrodynamical and semi-analytical simulations and provide context for interpreting JWST (James Webb Space Telescope) metallicity and dust measurements, highlighting the importance of episodic star formation in early galaxy chemical evolution. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2508_08363 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | On bursty star formation during cosmological reionization -- influence on the metal and dust content of low-mass galaxies Menon, Anand Balu, Sreedhar Power, Chris Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics Observations indicate that high-redshift galaxies undergo episodic star formation bursts, driving strong outflows that expel gas and suppress accretion. We investigate the consequences for metal and dust content of galaxies at $z \geq 5$ using our semi-analytical model, ASHVINI. We track gas-phase and stellar metallicities ($Z_{\rm g}, Z_\ast$) and dust mass (M$_{\rm d}$) in dark matter haloes spanning $M_{\rm halo} = 10^6$-$10^{11}$ $M_\odot$, comparing continuous and bursty star formation scenarios - which reflect underlying assumptions of instantaneous and delayed feedback - and we allow for metallicity-dependent feedback efficiency. Delayed feedback induces oscillations in $Z_{\rm g}$ and $Z_\ast$, with $Z_{\rm g}$ declining sharply at low stellar and halo masses; the mass scale of this decline increases toward lower redshift. Reionization introduces significant scatter in $Z_{\rm g}$, producing an upturn followed by rapid decline. Metallicity-dependent feedback moderates this decline at $ z=7 - 10$, flattening the $Z_{\rm g}$-mass relation to $\simeq 0.03$-$0.04\, Z_\odot$. Dust production tracks $Z_{\rm g}$ but is sensitive to burst history, causing delayed enrichment. Our results show that burst-driven feedback decouples $Z_{\rm g}$ and $Z_\ast$, imprints intrinsic scatter in mass-metallicity relations, and delays dust growth. These effects are strongest in low-mass halos ($M_{\rm halo} \sim 10^7 M_\odot$), where shallow potentials amplify the impact of feedback. Our results are consistent with recent hydrodynamical and semi-analytical simulations and provide context for interpreting JWST (James Webb Space Telescope) metallicity and dust measurements, highlighting the importance of episodic star formation in early galaxy chemical evolution. |
| title | On bursty star formation during cosmological reionization -- influence on the metal and dust content of low-mass galaxies |
| topic | Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2508.08363 |