揭示宏伟设计旋涡星系中的金属混合：对M83的紫外-光学多相空间分辨研究
Unveiling Metal Mixing in a Grand-Design Spiral: A UV-optical multiphase spatially resolved study of M83
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中文总结 AI 辅助
本研究结合HST/COS、VLT/MUSE和LBT/MODS数据，对M83的18个年轻星团开展空间分辨多相化学增丰研究，揭示不同元素的增丰特征及气体相金属混合效率。
中文摘要 AI 辅助
我们结合哈勃空间望远镜（HST）的宇宙起源光谱仪（COS）获取的远紫外吸收线光谱，以及甚大望远镜（VLT）的多单元光谱探测器（MUSE）和大双筒望远镜（LBT）的多目标摄谱仪（MODS）获取的共空间光学光谱，对邻近宏伟设计旋涡星系M83中年轻星团（YSCs）周围的化学增丰开展空间分辨的多相研究。我们的样本包含18个年轻星团，其光谱年龄约为1至6百万年，银心半径覆盖至R/R₂₅=0.56。我们通过紫外吸收线光谱推导中性氢（H I）的丰度，并与经红化校正的光学发射线得到的电离氢（H II）丰度进行对比。由于并非所有区域都检测到极光线，我们开发并应用了一种基于强线诊断的经验多区电子温度（Tₑ）校准方法，以估算电子温度并推导可靠的星云丰度。我们测量了氧（O）、硫（S）、氮（N）和铁（Fe）的丰度，这些元素追踪不同核合成通道的增丰情况。α元素（O和S）表现出相似的行为，与核心坍缩超新星的增丰一致；而铁的变化较弱，反映了Ia型超新星的延迟产生。氮呈现出最大的相偏移（电离相-中性相），电离气体相对于中性相的氮丰度增强可达ΔN/H≈1.5 dex、ΔN/O>1.5 dex，表明大质量恒星的局部增丰以及气体相在百万年时间尺度上的混合效率低下。电离气体呈现出反馈调控化学增丰和大尺度丰度梯度的特征，而中性气体中的对应趋势较弱或不存在，这与宏伟设计旋涡星系中星团演化最早阶段金属大多局限于直接恒星形成环境的情况相符。
英文摘要
We present a spatially resolved, multiphase study of chemical enrichment around young star clusters (YSCs) in the nearby grand-design spiral M83 by combining far-ultraviolet(UV) absorption-line spectroscopy from HST/COS with cospatial optical spectroscopy from VLT/MUSE and LBT/MODS. Our sample includes 18 YSCs spanning spectroscopic ages of ~1-6 Myr and galactocentric radii out to R/R_{25}=0.56. Neutral (H I) abundances were derived from UV absorption-line spectroscopy and compared with ionised (H II) abundances from reddening-corrected optical emission lines. Because auroral lines are not detected in all regions, we develop and apply an empirical multi-zone electron temperature (T_e) calibration based on strong-line diagnostics to estimate T_e and derive reliable nebular abundances. We measure oxygen(O), sulphur(S), nitrogen(N), and iron(Fe) abundance tracing enrichment from distinct nucleosynthetic channels. The alpha-elements (O and S) exhibit similar behaviour, consistent with enrichment by core-collapse supernovae, whereas Fe shows weaker variations, reflecting its delayed production by Type Ia supernovae. Nitrogen displays the largest phase offset (ionised-neutral), with enhancements of up to $Delta$N/H~1.5 dex and $Delta$N/O>1.5 dex in the ionised gas relative to the neutral phase, indicating localised enrichment by massive stars and inefficient mixing between gas phases on Myr timescales. While the ionised gas exhibits signatures of feedback-regulated chemical enrichment and large-scale abundance gradients, corresponding trends are weak or absent in the neutral gas, consistent with metals remaining largely confined to the immediate star-forming environment during the earliest stages of cluster evolution in a massive grand-design spiral.
