A negative stellar mass$-$gaseous metallicity gradient relation of dwarf galaxies modulated by stellar feedback
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| Main Authors: | , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| author | Li, Tie Zhang, Hong-Xin Lyu, Wenhe Tang, Yimeng Yao, Yao Wang, Enci Rong, Yu Chen, Guangwen Kong, Xu Bian, Fuyan Gu, Qiusheng Johnston, J. Evelyn Li, Xin Mao, Shude Shi, Yong Wang, Junfeng Wang, Xin Yu, Xiaoling Zheng, Zhiyuan |
| author_facet | Li, Tie Zhang, Hong-Xin Lyu, Wenhe Tang, Yimeng Yao, Yao Wang, Enci Rong, Yu Chen, Guangwen Kong, Xu Bian, Fuyan Gu, Qiusheng Johnston, J. Evelyn Li, Xin Mao, Shude Shi, Yong Wang, Junfeng Wang, Xin Yu, Xiaoling Zheng, Zhiyuan |
| contents | Baryonic cycling is reflected in the spatial distribution of metallicity within galaxies, yet gas-phase metallicity distribution and its connection with other properties of dwarf galaxies are largely unexplored. We present the first systematic study of radial gradients of gas-phase metallicities for a sample of 55 normal nearby star-forming dwarf galaxies (stellar mass $M_\star$ ranging from $10^7$ to $10^{9.5}\ M_\odot$), based on MUSE spectroscopic observations. We find that metallicity gradient shows a significant negative correlation (correlation coefficient $r \approx -0.56$) with $\log M_\star$, in contrast to the flat or even positive correlation observed for higher-mass galaxies. This negative correlation is accompanied by a stronger central suppression of metallicity compared to the outskirts in lower-mass galaxies. Among the other explored galaxy properties-including baryonic mass, star formation distribution, galaxy environment, regularity of the gaseous velocity field, and effective yield of metals $y_{\rm eff}$-only the velocity field regularity and $y_{\rm eff}$ show residual correlation with the metallicity gradient after controlling for $M_\star$, in the sense that galaxies with irregular velocity fields or lower $y_{\rm eff}$ tend to have less negative or more positive gradients. Particularly, a linear combination of $\log M_\star$ and $\log y_{\rm eff}$ significantly improves the correlation with metallicity gradient ($r \approx -0.68$) compared to $\log M_\star$ alone. The lack of correlation with environment disfavors gas accretion as a dominant factor. Our findings imply that metal mixing and transport processes, including but not limited to feedback-driven outflows, are more important than in-situ metal production in shaping the metallicity distribution of dwarf galaxies. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_17541 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | A negative stellar mass$-$gaseous metallicity gradient relation of dwarf galaxies modulated by stellar feedback Li, Tie Zhang, Hong-Xin Lyu, Wenhe Tang, Yimeng Yao, Yao Wang, Enci Rong, Yu Chen, Guangwen Kong, Xu Bian, Fuyan Gu, Qiusheng Johnston, J. Evelyn Li, Xin Mao, Shude Shi, Yong Wang, Junfeng Wang, Xin Yu, Xiaoling Zheng, Zhiyuan Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics Solar and Stellar Astrophysics Baryonic cycling is reflected in the spatial distribution of metallicity within galaxies, yet gas-phase metallicity distribution and its connection with other properties of dwarf galaxies are largely unexplored. We present the first systematic study of radial gradients of gas-phase metallicities for a sample of 55 normal nearby star-forming dwarf galaxies (stellar mass $M_\star$ ranging from $10^7$ to $10^{9.5}\ M_\odot$), based on MUSE spectroscopic observations. We find that metallicity gradient shows a significant negative correlation (correlation coefficient $r \approx -0.56$) with $\log M_\star$, in contrast to the flat or even positive correlation observed for higher-mass galaxies. This negative correlation is accompanied by a stronger central suppression of metallicity compared to the outskirts in lower-mass galaxies. Among the other explored galaxy properties-including baryonic mass, star formation distribution, galaxy environment, regularity of the gaseous velocity field, and effective yield of metals $y_{\rm eff}$-only the velocity field regularity and $y_{\rm eff}$ show residual correlation with the metallicity gradient after controlling for $M_\star$, in the sense that galaxies with irregular velocity fields or lower $y_{\rm eff}$ tend to have less negative or more positive gradients. Particularly, a linear combination of $\log M_\star$ and $\log y_{\rm eff}$ significantly improves the correlation with metallicity gradient ($r \approx -0.68$) compared to $\log M_\star$ alone. The lack of correlation with environment disfavors gas accretion as a dominant factor. Our findings imply that metal mixing and transport processes, including but not limited to feedback-driven outflows, are more important than in-situ metal production in shaping the metallicity distribution of dwarf galaxies. |
| title | A negative stellar mass$-$gaseous metallicity gradient relation of dwarf galaxies modulated by stellar feedback |
| topic | Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2504.17541 |