AI 中文总结
研究旋涡星系 NGC1385 的演化，结合多种巡天数据构建相关分布并测量金属丰度，用化学演化模型拟合观测数据，揭示其具有典型由内向外盘形成特征及高恒星形成效率，模型预测与观测吻合，支持分析和演化情景。
AI 中文摘要
旋涡星系 NGC 1385 的特点是具有活跃且持久的恒星形成历史，尤其是在其中心区域，导致当前的恒星形成率超过了类似星系。我们利用从 PHANGS 巡天获得的空间分辨光学和亚毫米光谱，并结合 WALLABY 射电巡天数据，来分析该星系的演化历史。我们构建了恒星形成率、星际介质（ISM）中性和分子气体质量面密度的径向分布，并使用改进的全光谱拟合恒星群体合成方法测量恒星群体的金属丰度分布，同时利用 H II 区发射线确定 ISM 氧丰度。年轻恒星和 ISM 的金属丰度相似，且分布几乎平坦，这与之前发现恒星平均金属丰度呈正梯度的工作有很大不同。我们将一个化学演化模型（包括气体吸积、外流和径向流入）拟合到 NGC 1385 的观测数据上。基于此拟合，NGC 1385 的演化具有旋涡星系典型的由内向外的盘形成特征，尽管我们的模型并未事先假设内盘的气体吸积时间尺度比外盘短。然而，该星系在数十亿年的时间尺度上经历了持续的恒星形成，恒星形成效率比正常情况高两倍。这解释了年轻恒星的高金属丰度比太阳高 0.15 至 0.2 dex 以及盘上金属丰度的平坦分布。恒星金属丰度的模型预测与观测值吻合良好，支持了我们改进的光谱拟合分析和推断的演化情景的稳健性。
英文摘要
The spiral galaxy NGC 1385 is characterized by a vigorous and protracted history of star formation, particularly in its central regions, leading to a current star formation rate that surpasses those of comparable systems. We analyze the evolution history of the galaxy using spatially resolved optical and submillimeter spectroscopy obtained from the PHANGS survey combined with WALLABY radio survey data. We construct radial distributions of star formation rate and the interstellar medium (ISM) neutral and molecular gas mass surface densities and measure the metallicity distribution of the stellar populations using a refined full-spectral fitting population synthesis method together with a determination of ISM oxygen abundances using H\,II region emission lines. The metallicities of the young stars and the ISM are similar and show an almost flat distribution. This is crucially different from previous work which had found a positive gradient for the average metallicities of the stars. We fit a chemical evolution model (incorporating gas infall, outflow, and radial inflow) to the observed data of NGC\,1385. Based on this fit, the evolution of NGC\,1385 is characterized by the typical inside-out disk formation of spiral galaxies -- even though our model does not assume an a priori shorter gas infall timescale for the inner disk than for the outer disk. However, the galaxy has experienced sustained star formation over gigayear timescales with a star formation efficiency a factor of two higher than normal. This explains the high metallicity of the young stars of 0.15 to 0.2\,dex higher than solar and the flat distribution of metallicity across the disk. The model predictions for the metallicities of the stars align well with the observed values, supporting the robustness of both our refined spectral fitting analysis and the inferred evolutionary scenario.
Comments15 pages, 14 figures, accepted for publication in A&A
