发表机构
Princeton University; Tel Aviv University; Stanford University; University of California, Santa Cruz; Lawrence Berkeley National Laboratory; The Ohio State University; Amherst College（普林斯顿大学; 特拉维夫大学; 斯坦福大学; 加州大学圣克鲁兹分校; 劳伦斯伯克利国家实验室; 俄亥俄州立大学; 阿默斯特学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用Merian巡天和DESI数据，发现低于基本金属丰度关系的星系在形态上更受扰动，表明形态可作为FMR的额外维度，并支持外部爆发触发机制。
AI 中文摘要
经验研究揭示了星系金属丰度、恒星质量与恒星形成率之间的联系，即基本金属丰度关系（FMR），其中金属丰度随恒星质量增加而升高，随恒星形成率增加而降低。对FMR的物理解释表明，活跃恒星形成的星系由原始气体供能，这些气体可能通过星系际介质吸积或小型并合获得。在此，我们展示了星系形态作为FMR中额外维度的价值。利用Merian巡天的中带成像，我们为具有DESI DR1光谱的大样本星系构建了恒星连续谱和H$\alpha$发射的空间分辨图，样本恒星质量低至$10^8$ M$_\odot$。我们从发射图中测量非参数形态参数，并使用强线校准从光谱中推导气体相氧丰度。我们拟合了一系列简单线性模型，以探索金属丰度、恒星质量、比恒星形成率（sSFR）和形态参数之间的相关性。我们发现，比FMR预测更贫金属的星系显得特别受到扰动。在固定恒星质量和sSFR下，金属丰度与连续谱和H$\alpha$形态的不对称性呈负相关。观测到的趋势——以及特别贫金属、形态扰动、高度恒星形成的星系的存在——与外部爆发触发机制一致。我们的结果表明，星系的形态与其金属丰度和恒星形成历史相关，为低质量星系中恒星形成增强的物理驱动因素提供了额外的观测探针。
英文摘要
Empirical results have revealed a connection between a galaxy's metallicity, mass, and star formation rate, known as the fundamental metallicity relation (FMR), in which metallicity increases with stellar mass and decreases with SFR. Physical interpretations of the FMR suggest that actively star-forming galaxies are fueled by pristine gas, likely obtained via IGM accretion or minor mergers. Here we demonstrate the value of galaxy morphology as an additional axis in the FMR. Using medium-band imaging from the Merian Survey, we construct spatially resolved maps of stellar continuum and H$α$ emission for a large sample of galaxies with DESI DR1 spectra, reaching stellar masses down to $10^8$ M$_\odot$. We measure non-parametric morphological parameters from the emission maps and derive gas-phase oxygen abundances from the spectra using strong-line calibrations. We fit a series of simple linear models to explore correlations among the metallicity, stellar mass, sSFR, and morphological parameters. We find that galaxies that are more metal-poor than predicted by the FMR appear particularly disturbed. At fixed stellar mass and sSFR, metallicity is inversely correlated with the asymmetry of both the continuum and H$α$ morphology. The observed trends -- and the existence of particularly metal-poor, morphologically disturbed, highly star-forming galaxies -- are consistent with external burst triggering. Our results indicate that a galaxy's morphology is linked to its metallicity and star formation history, providing an additional observational probe of the physical drivers of elevated star-formation in low-mass galaxies.
CommentsSubmitted to ApJ
