arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0706.3035astro-ph
收藏

NGC 6334恒星形成区的大质量团块

Massive Clumps in the NGC 6334 Star Forming Region

Diego J. Munoz, Diego Mardones, Guido Garay, David Rebolledo, Kate Brooks, Sylvain Bontemps

备注：
16 pages, 11 figures, 4 tables. To appear in the Astrophysical Journal
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

我们报告的观测尘埃连续发射1.2毫米朝向恒星形成区NGC 6334与SEST SIMBA测辐射热计阵列。观测覆盖了$\sim 2$平方度的区域，具有近似均匀的噪声。我们检测到181个团块，其质量跨越几乎三个数量级（3个\Msun $-6\times10^3$ \Msun），大小范围为0.1- 1.0 pc。我们发现，集团质量函数$dN/d\log M$很好地符合指数为-0.6的质量幂律（或等价于$dN/dM \propto M^{-1.6}$）。导出的指数是类似的分子线发射调查，是显着不同的恒星初始质量函数。我们研究了质谱的变化，通过改变对团块的温度分布和自由-自由发射对1.2 mm发射的贡献的假设，发现指数变化不大。还对累积质量分布函数进行了分析，在不包括高质量端（幂律拟合不再有效）的质量范围内给出了一致的结果。在NGC 6334中观察到的团块的质量和大小表明它们不是恒星的直接祖先，并且碎片化过程决定了后来的质量分布或发生在较小的空间尺度上。NGC 6334中团块的空间分布揭示了与其他恒星形成区中年轻恒星所表现出的集群非常相似的集群。一个幂律拟合的表面密度的同伴给$Σ\propto θ^{-0.62}$。

英文摘要：

We report observations of dust continuum emission at 1.2 mm toward the star forming region NGC 6334 made with the SEST SIMBA bolometer array. The observations cover an area of $\sim 2$ square degrees with approximately uniform noise. We detected 181 clumps spanning almost three orders of magnitude in mass (3\Msun$-6\times10^3$ \Msun) and with sizes in the range 0.1--1.0 pc. We find that the clump mass function $dN/d\log M$ is well fit with a power law of the mass with exponent -0.6 (or equivalently $dN/dM \propto M^{-1.6}$). The derived exponent is similar to those obtained from molecular line emission surveys and is significantly different from that of the stellar initial mass function. We investigated changes in the mass spectrum by changing the assumptions on the temperature distribution of the clumps and on the contribution of free-free emission to the 1.2 mm emission, and found little changes on the exponent. The Cumulative Mass Distribution Function is also analyzed giving consistent results in a mass range excluding the high-mass end where a power-law fit is no longer valid. The masses and sizes of the clumps observed in NGC 6334 indicate that they are not direct progenitors of stars and that the process of fragmentation determines the distribution of masses later on or occurs at smaller spatial scales. The spatial distribution of the clumps in NGC 6334 reveals clustering which is strikingly similar to that exhibited by young stars in other star forming regions. A power law fit to the surface density of companions gives $Σ\propto θ^{-0.62}$.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑