The Spectral Energy Distributions of Infant Super-Star Clusters in Henize 2-10 from 7 Millimeters to 6 Centimeters
The Spectral Energy Distributions of Infant Super-Star Clusters in Henize 2-10 from 7 Millimeters to 6 Centimeters
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Henize 2-10 幼年超级星团从 7 毫米到 6 厘米的光谱能量分布
DOI：
10.1086/378585
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
H. Kobulnicky
中科院分区：
文献类型：
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作者：
Kelsey E. Johnson;H. Kobulnicky
我们目前的意见，从我们的持续研究的最早阶段的大规模星星集群的演变。本文利用甚大天线阵0.7、1.3、2、3.6和6 cm波段的射电观测数据，绘制了Henize 2-10超年轻嵌入超星团的射电谱能量分布图，并模拟了其物理性质。0.7厘米的通量密度表明，年轻的嵌入式星星集群是无线电探测到的“超密（UD）H II区域”的动力，质量大于~105 M。我们模拟的无线电频谱能量分布的恒定密度H II区域和H II区域与幂律电子密度梯度。这些模型表明，UD H II区域的半径范围在~2和4 pc之间，平均电子密度为~103-104 cm-3（峰值电子密度达到~105-106 cm-3）。这些密度所暗示的压力为P/kB ~ 107-1010 cm-3 K，比银河系星际介质中的典型压力高出几个数量级。在UD H II区域的H II质量推断为~（2-8）× 103 M;这些值小于嵌入恒星质量的5%，与光学可见的年轻星团相比非常低。我们认为，这些低H II质量分数可能是这些对象的极端年轻的结果。
We present observations from our continuing studies of the earliest stages of massive star cluster evolution. In this paper, radio observations from the Very Large Array at 0.7, 1.3, 2, 3.6, and 6 cm are used to map the radio spectral energy distributions and model the physical properties of the ultrayoung embedded super-star clusters in Henize 2-10. The 0.7 cm flux densities indicate that the young embedded star clusters that are powering the radio-detected "ultradense (UD) H II regions" have masses greater than ~105 M☉. We model the radio spectral energy distributions as both constant-density H II regions and H II regions with power-law electron density gradients. These models suggest that the UD H II regions have radii ranging between ~2 and 4 pc and average electron densities of ~103-104 cm-3 (with peak electron densities reaching values of ~105-106 cm-3). The pressures implied by these densities are P/kB ~ 107-1010 cm-3 K, several orders of magnitude higher than typical pressures in the Galactic interstellar medium. The inferred H II masses in the UD H II regions are ~(2-8) × 103 M☉; these values are less than 5% of the embedded stellar masses and anomalously low when compared with optically visible young clusters. We suggest that these low H II mass fractions may be a result of the extreme youth of these objects.