发表机构
European Southern Observatory; Instituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales; Department of Physics, Presidency University; School of Earth and Space Exploration, Arizona State University; School of Astrophysics, Presidency University（欧洲南方天文台; 迭戈帕托利亚斯大学工程与科学学院天体物理研究所; 总统大学物理系; 亚利桑那州立大学地球与太空探索学院; 总统大学天体物理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
基于MaNGA数据，研究发现低质量星系金属丰度梯度主要由内部结构（光集中度）决定，而非环境，且梯度平均平坦。
AI 中文摘要
矮星系和低质量星系对恒星反馈和气体流动高度敏感，然而其空间分辨的气相金属丰度仍缺乏充分表征。我们利用MaNGA DR17数据测量了382个恒星形成低质量星系的径向气相金属丰度梯度，覆盖$7.2 \leq \log(M_{\star}/M_{\odot}) \leq 9.1$且$z \leq 0.05$的范围。光谱在椭圆径向分箱内叠加，金属丰度由N2指数推导。在移除对局部恒星质量面密度的主要依赖后，我们定义残差金属丰度$\Delta Z$以隔离次要依赖。梯度平均而言是平坦的（中值斜率为$-0.007$ dex $R_e^{-1}$）。残差梯度与光集中度（$r = 0.304$，$r^2 = 0.092$，$p < 0.001$）和气体速度弥散（$r = 0.204$，$p < 0.001$）的相关性最强，但两者至多解释9%的方差。大尺度环境未显示显著相关性。集中度结果对测量不确定性具有稳健性，并在更严格的分辨率截断下依然存在，表明内部结构特性塑造了低质量星系中径向金属分布。
英文摘要
Dwarf and low-mass galaxies are highly sensitive to stellar feedback and gas flows, yet their spatially resolved gas-phase metallicity remains poorly characterised. We measure radial gas-phase metallicity gradients for 382 star-forming low-mass galaxies from MaNGA DR17, spanning $7.2 \leq \log(M_{\star}/M_{\odot}) \leq 9.1$ and $z \leq 0.05$. Spectra are stacked in elliptical radial bins and metallicity is derived from the N2 index. After removing the primary dependence on local stellar mass surface density, we define a residual metallicity $ΔZ$ to isolate secondary dependencies. Gradients are flat on average (median slope $-0.007$\,dex\,$R_e^{-1}$). The residual gradients correlate most strongly with light concentration ($r = 0.304$, $r^2 = 0.092$, $p < 0.001$) and gas velocity dispersion ($r = 0.204$, $p < 0.001$), though both account for at most 9 per cent of the variance. Large-scale environment shows no significant correlation. The concentration result is robust to measurement uncertainties and persists with a stricter resolution cut, suggesting internal structural properties shape the radial metal distribution in low-mass galaxies.
Comments19 pages, 15 figures, 2 tables. Full data table available as online supplementary material
