Interpreting the sub-linear Kennicutt–Schmidt relationship: the case for diffuse molecular gas
Interpreting the sub-linear Kennicutt–Schmidt relationship: the case for diffuse molecular gas
复制标题
解释亚线性肯尼卡特-施密特关系：扩散分子气体的情况
DOI：
10.1093/mnras/stu919
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发表时间：
2014
影响因子：
4.8
通讯作者：
R. Klessen
中科院分区：
文献类型：
--
作者：
R. Shetty;P. Clark;R. Klessen
最近对两个河外观测巡天的统计分析强烈表明，星星形成率（KSFR）和分子气体表面密度（KSmol）之间存在亚线性的肯尼库特-施密特（KS）关系。在这里，我们认为这些结果的后果的背景下，共同的假设，以及观测支持的线性关系之间的关系，致密气体的表面密度的COSFR。如果CO示踪气体耗尽时间（τ CO dep
τdepCO
如果CO只追踪形成恒星的巨分子云（GMC），那么每个GMC的物理性质一定是不同的，例如体积密度或星星形成速率。另一种可能性是，CO光度和XCO因子之间的转换因云而异。一个更直接的解释是，CO渗透到分级星际介质中，包括细丝和GMC嵌入的低密度区域。一些独立的观测结果支持这一描述，扩散气体至少占总分子含量的30%。CO亮扩散气体可以解释亚线性KS关系，并导致τ CO dep增大
τdepCO
关于Escherichia如果KSFR与致密气体表面密度线性相关，则亚线性KS关系表明扩散气体fdiff的分数随着KSmol的增加而增加。在星系中，fdiff的福尔斯落向外盘，这种描述表明，fdiff也径向减少。
Recent statistical analysis of two extragalactic observational surveys strongly indicate a sub-linear Kennicutt–Schmidt (KS) relationship between the star formation rate (ΣSFR) and molecular gas surface density (Σmol). Here, we consider the consequences of these results in the context of common assumptions, as well as observational support for a linear relationship between ΣSFR and the surface density of dense gas. If the CO traced gas depletion time (τ CO dep
τdepCO
) is constant, and if CO only traces star-forming giant molecular clouds (GMCs), then the physical properties of each GMC must vary, such as the volume densities or star formation rates. Another possibility is that the conversion between CO luminosity and Σmol, the XCO factor, differs from cloud-to-cloud. A more straightforward explanation is that CO permeates the hierarchical interstellar medium, including the filaments and lower density regions within which GMCs are embedded. A number of independent observational results support this description, with the diffuse gas comprising at least 30 per cent of the total molecular content. The CO bright diffuse gas can explain the sub-linear KS relationship, and consequently leads to an increasing τ CO dep
τdepCO
with Σmol. If ΣSFR linearly correlates with the dense gas surface density, a sub-linear KS relationship indicates that the fraction of diffuse gas fdiff grows with Σmol. In galaxies where Σmol falls towards the outer disc, this description suggests that fdiff also decreases radially.
DOI：
10.1088/0004-637x/779/1/42
发表时间：
2013-04
期刊：
The Astrophysical Journal
影响因子：
--
作者：
E. Schinnerer;S. Meidt;J. Pety;A. Hughes;D. Colombo;S. García-Burillo;K. Schuster;G. Dumas;C. Dobbs;A. Leroy;C. Kramer;T. Thompson;M. Regan
通讯作者：
E. Schinnerer;S. Meidt;J. Pety;A. Hughes;D. Colombo;S. García-Burillo;K. Schuster;G. Dumas;C. Dobbs;A. Leroy;C. Kramer;T. Thompson;M. Regan
DOI：
10.1088/0004-6256/140/5/1194
发表时间：
2010-07
期刊：
The Astronomical Journal
影响因子：
--
作者：
F. Bigiel;A. Leroy;F. Walter;L. Blitz;E. Brinks;W. D. Blok;B. M. U. Berkeley;Mpia Heidelberg;Nrao;U. Hertfordshire;U. C. Town;C. Observatories
通讯作者：
F. Bigiel;A. Leroy;F. Walter;L. Blitz;E. Brinks;W. D. Blok;B. M. U. Berkeley;Mpia Heidelberg;Nrao;U. Hertfordshire;U. C. Town;C. Observatories