发表机构
NASA Goddard Space Flight Center; University of Maryland, College Park; Center for Research and Exploration in Space Science and Technology, NASA Goddard Space Flight Center; Astrochemistry Laboratory, NASA Goddard Space Flight Center; Kagawa University; University of Virginia; Keele University（美国宇航局戈达德太空飞行中心; 马里兰大学帕克分校; 空间科学与技术研究探索中心，美国宇航局戈达德太空飞行中心; 天体化学实验室，美国宇航局戈达德太空飞行中心; 香川大学; 弗吉尼亚大学; 基尔大学）
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ALMA对LMC中N83恒星形成区进行高分辨率观测，识别出两个热核和多个冷核，探测到复杂有机分子，并发现紫外辐射和激波显著影响化学组成与丰度。
AI 中文摘要
我们报告了使用阿塔卡马大型毫米/亚毫米阵列（ALMA）对大麦哲伦云（LMC）中恒星形成区N83的两个天区进行的1.2毫米连续谱和分子线约0.1秒差距尺度观测的结果。本研究是探索LMC低金属丰度和高紫外通量环境中分子复杂性的系列调查中的第三项。我们基于XCLASS的谱建模和连续谱发射分析，确定了ALMA探测到的五个源的物理和化学性质。源N83A-mm A和B的温度超过100 K、尺寸小且H$_2$体积密度高，表明它们是热核。N83A-mm A/B与复杂有机分子相关：甲醇（CH$_3$OH）、甲基氰（CH$_3$CN）和二甲醚（CH$_3$OCH$_3$）。我们还在三个冷核中发现了CH$_3$OH，并在两个天区中发现了扩展的冷CH$_3$OH发射。我们在至少一个核中探测到了SO、$^{33}$SO、SO$_2$、OCS、H$_2$CS、CS、C$^{33}$S、HC$^{15}$N、H$^{13}$CN、HNCO、HDCO、H$^{13}$CO$^{+}$、SiO和CH$_2$CO。相对于H$_2$的分子丰度符合先前报道的麦哲伦热核趋势：CH$_3$OH丰度变化显著，而含硫物种的丰度变化较小。我们在N83的两个ALMA天区中发现了强紫外辐射和复杂运动的证据。反馈产生的激波是热核内外含硫物种、SiO和CH$_3$OH化学的重要驱动因素。局部效应对LMC中恒星形成核的化学组成和丰度有重大影响。
英文摘要
We report the results of the 1.2 mm continuum and molecular line $\sim$0.1 parsec-scale observations with the Atacama Large Millimeter/submillimeter Array of two fields in the star-forming region N83 in the Large Magellanic Cloud (LMC). This study is third in a series of investigations exploring molecular complexity in a low-metallicity and high UV flux environment of the LMC. We determine the physical and chemical properties of five sources detected with ALMA based on spectral modeling with XCLASS and the analysis of the continuum emission. The temperatures exceeding 100 K, small sizes, and high H$_2$ volume densities of sources N83A-mm A and B indicate that they are hot cores. N83A-mm A/B are associated with complex organic molecules: methanol (CH$_3$OH), methyl cyanide (CH$_3$CN), and dimethyl ether (CH$_3$OCH$_3$). We also found CH$_3$OH in three cold cores, and extended cold CH$_3$OH emission in both fields. We detected SO, $^{33}$SO, SO$_2$, OCS, H$_2$CS, CS, C$^{33}$S, HC$^{15}$N, H$^{13}$CN, HNCO, HDCO, H$^{13}$CO$^{+}$, SiO, and CH$_2$CO in at least one core. Molecular abundances with respect to H$_2$ fit into the trends previously reported for the Magellanic hot cores: the CH$_3$OH abundance varies significantly, while the abundances of S-bearing species show small variations. We found evidence for strong UV radiation and complex kinematics in both ALMA fields in N83. The feedback-produced shocks are important drivers of the chemistry of S-bearing species, SiO, and CH$_3$OH in and outside hot cores. Local effects have a large impact on the chemical composition and abundances of star-forming cores in the LMC.
CommentsAccepted for publication in The Astrophysical Journal; 63 pages, 4 tables, 39 figures
