Title: HST FUV Spectroscopy of Super Star Cluster A in the Green Pea Analog Mrk 71: Revealing the Presence of Very Massive Stars Show Chinese title

Title: 哈勃空间望远镜FUV光谱学研究绿豌豆类似体Mrk 71中的超级星团A：揭示非常大质量恒星的存在

Abstract: Mrk 71 is a low metallicity (Z = 0.16 Z_sun) starburst region in the local dwarf galaxy NGC 2366, hosting two super star clusters (SSCs A and B), and is recognized as a Green Pea (GP) analog with SSC A responsible for the GP properties. We present STIS and FOS far-ultraviolet (FUV) spectra of the embedded SSC Mrk 71-A obtained with the Hubble Space Telescope (HST). The STIS FUV spectrum shows the characteristic features of very massive stars (VMS, masses > 100 M_sun) and we derive an age of 1+/-1 Myr by comparison with the Charlot & Bruzual suite of spectral population synthesis models with upper mass limits of 300 and 600 M_sun. We compare the STIS spectrum with all known SSC spectra exhibiting VMS signatures: NGC 5253-5, R136a, NGC 3125-A1 and the z = 2.37 Sunburst cluster. We find that the cluster mass-loss rates and wind velocities, as characterized by the C IV P Cygni profiles and the He II emission line strengths, are very similar over Z = 0.16 to 0.4 Z_sun. This agrees with predictions that the optically thick winds of VMS will be enhanced near the Eddington limit and show little metallicity dependence. We find very strong damped Lyman-alpha absorption with log N(H I) = 22.2 cm-2 associated with Mrk 71-A. We discuss the natal environment of this young SSC in terms of radiatively-driven winds, catastrophic cooling and recent models where the cluster is surrounded by highly pressurized clouds with large neutral columns. Show Chinese abstract

Abstract: 马克71是本地矮星系NGC 2366中的一个低金属度（Z = 0.16 Z_sun）星爆区域，包含两个超星团（SSC A和B），并被认定为绿豌豆（GP）的类似物，其中SSC A负责GP的特性。 我们展示了利用哈勃空间望远镜（HST）获得的嵌入式SSC马克71-A的STIS和FOS远紫外（FUV）光谱。 STIS的FUV光谱显示了非常大质量恒星（VMS，质量> 100 M_sun）的特征，并通过与Charlot & Bruzual的光谱人口合成模型套件进行比较，得出其年龄为1+/-1 Myr，上限质量分别为300和600 M_sun。 我们将STIS光谱与所有已知表现出VMS特征的SSC光谱进行了比较：NGC 5253-5、R136a、NGC 3125-A1和红移为2.37的太阳爆发星团。 我们发现，根据C IV P Cygni轮廓和He II发射线强度表征的星团质量损失率和风速，在Z = 0.16到0.4 Z_sun范围内非常相似。 这与预测一致，即VMS的光学厚风将在爱丁顿极限附近增强，并且金属度依赖性很小。 我们发现与马克71-A相关的非常强的阻尼莱曼阿尔法吸收，log N(H I) = 22.2 cm-2。 我们从辐射驱动风、灾难性冷却以及最近的模型角度讨论了这个年轻SSC的诞生环境，其中星团被高压力云包围，具有大的中性柱密度。