标题： 揭示围绕大质量原恒星GGD27 MM1的原恒星盘群集 显示英文标题

标题： Unveiling a cluster of protostellar disks around the massive protostar GGD27 MM1

摘要： 我们利用ALMA以前所未有的角分辨率（40毫角秒，即56天文单位）和灵敏度（0.002倍太阳质量）观测了恒星形成区GGD27的1.14毫米波段。我们探测到一个由25个连续谱源组成的星团，其中大多数很可能追踪的是零级/一级原恒星周围的盘。 在排除了两个最 massive 的天体后，盘的质量范围在0.003到0.05倍太阳质量之间。 对该星团性质的分析表明，GGD27显示出适度的次结构化。 这一结果结合射电喷流的动力学时间尺度（10000年），表明该星团非常年轻。 缺乏盘质量分离的特征也可能支持这一点。 我们发现大半径盘（Rdisk >100 au）明显不足。 半径的中值值为34天文单位，小于塔乌斯的92天文单位中值，但与奥克塔维亚斯和猎户座星云中的值相当。 在GGD27中没有距离相关的盘质量分布证据（即由于外部光蒸发导致的盘质量减少），这很可能是因为星团的年轻。 在距离<0.02秒差距的情况下，盘的数量明显不足。 只有在距离>0.04秒差距时，恒星才能形成更大更 massive 的盘，这表明远离星团中心的动态相互作用较弱，尽管发现的小盘可能是盘截断的结果。 这项工作展示了从遥远且 massive （仍深深嵌入）的聚集体环境中低质量原恒星的盘进行表征的潜力。 显示英文摘要

摘要： We used ALMA to observe the star-forming region GGD27 at 1.14 mm with an unprecedented angular resolution, 40 mas (56 au) and sensitivity (0.002 Msun). We detected a cluster of 25 continuum sources, most of which are likely tracing disks around Class 0/I protostars. Excluding the two most massive objects, disks masses are in the range 0.003-0.05 Msun. The analysis of the cluster properties indicates that GGD27 displays moderate subclustering. This result combined with the dynamical timescale of the radio jet (10000 years) suggests the youthfulness of the cluster. The lack of disk mass segregation signatures may support this too. We found a clear paucity of disks with Rdisk >100 au. The median value of the radius is 34 au, smaller than the median of 92 au for Taurus but comparable to the value found in Ophiuchus and in the Orion Nebula Cluster. In GGD27 there is no evidence of a distance-dependent disk mass distribution (i. e., disk mass depletion due to external photoevaporation), most likely due to the cluster youth. There is a clear deficit of disks for distances <0.02 pc. Only for distances >0.04 pc stars can form larger and more massive disks, suggesting that dynamical interactions far from the cluster center are weaker, although the small disks found could be the result of disk truncation. This work demonstrates the potential to characterize disks from low-mass YSOs in distant and massive (still deeply embedded) clustered environments.