ASTROCHEMICAL CORRELATIONS IN MOLECULAR CLOUDS
ASTROCHEMICAL CORRELATIONS IN MOLECULAR CLOUDS
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DOI：
10.1088/0004-637x/799/2/235
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发表时间：
2014-06
期刊：
影响因子：
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通讯作者：
B. Gaches;S. Offner;E. Rosolowsky;T. Bisbas
中科院分区：
文献类型：
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作者：
B. Gaches;S. Offner;E. Rosolowsky;T. Bisbas
我们研究了用于观察分子云的不同种类之间的光谱相关性。我们使用流体动力学模拟和一个完整的化学网络来研究典型银河系分子云中150多种物质的丰度。我们进行综合观察，以产生这些示踪剂的一个子集的发射图。我们研究了不同的视线和空间分辨率对发射分布的影响，并对物种之间进行了稳健的定量比较。我们使用光谱相关函数（SCF）来描述位置-位置-速度（PPV）空间中模拟云的结构，该函数量化了被一定长度尺度分隔的光谱之间的均方根差。我们预测观察到的SCF范围广泛的观察示踪剂，从而确定同源物种。特别是，我们发现C和CO、C+和CN、NH3和H2CS具有非常相似的scf。我们测量了所有物种的SCF斜率变化作为梁尺寸的函数，并证明梁尺寸对不同物种的排放有明显的影响。然而，对于高达10″的光束，将云置于1 kpc，变化不足以将SCF斜率移动到参数空间的不同区域。本研究结果为选择最佳示踪剂探测不同云长尺度提供了观测指导。
We investigate the spectral correlations between different species used to observe molecular clouds. We use hydrodynamic simulations and a full chemical network to study the abundances of over 150 species in typical Milky Way molecular clouds. We perform synthetic observations in order to produce emission maps of a subset of these tracers. We study the effects of different lines of sight and spatial resolution on the emission distribution and perform a robust quantitative comparison of the species to each other. We use the Spectral Correlation Function (SCF), which quantifies the root mean squared difference between spectra separated by some length scale, to characterize the structure of the simulated cloud in position–position–velocity (PPV) space. We predict the observed SCF for a broad range of observational tracers, and thus identify homologous species. In particular, we show that the pairs C and CO, C+ and CN, and NH3 and H2CS have very similar SCFs. We measure the SCF slope variation as a function of beam size for all species and demonstrate that the beam size has a distinct effect on different species emission. However, for beams of up to 10″, placing the cloud at 1 kpc, the change is not large enough to move the SCF slopes into different regions of parameter space. The results from this study provide observational guidance for choosing the best tracer to probe various cloud length scales.