论文标题
星际灰尘的质量不透明度与星际气体的表面密度之间的明显抗相关性
The apparent anti-correlation between the mass opacity of interstellar dust and the surface-density of interstellar gas
论文作者
论文摘要
$ {\ it Herschel} $观察的最新分析表明，在附近的盘状星系中，尘埃不透明的粉尘不透明性为$ 500 \，{\rmμm} $，$κ_{500} $，随着气体表面密度的增加，$σ__{\ rm ism ism} $（clark and。 $κ_{500} $和$σ_ {\ rm ism} $之间的这种明显的反相关与理论尘埃演化模型所期望的行为相反。在这样的型号中，浓密的灰尘，较冷的区域（即增加$σ_ {\ rm ism} $的区域倾向于增长，因此增加了$κ__{500} $。我们使用玩具模型表明，沿视线的一系列灰尘温度的存在可能导致$κ_{500} $的估计值较低。如果在较高$σ_{\ rm ism} $的区域中，灰尘温度的范围扩展到较低的值（似乎很可能），则这种效果的幅度可能足以解释$κ__{500} $和$σ_{\ rmMm ism} $之间的明显抗相关性。因此，与理论期望相反的固有灰尘特性可能不需要空间变化。
Recent analyses of ${\it Herschel}$ observations suggest that in nearby disc galaxies the dust mass opacity at $500 \, {\rm μm}$, $κ_{500}$, decreases with increasing gas surface density, $Σ_{\rm ISM}$ (Clark et al. 2019). This apparent anti-correlation between $κ_{500}$ and $Σ_{\rm ISM}$ is opposite to the behaviour expected from theoretical dust evolution models; in such models, dust in denser, cooler regions (i.e. regions of increased $Σ_{\rm ISM}$) tends to grow and therefore to have increased $κ_{500}$. We show, using a toy model, that the presence of a range of dust temperatures along the line of sight can lead to spuriously low estimated values of $κ_{500}$. If in regions of higher $Σ_{\rm ISM}$ the range of dust temperatures extends to lower values (as seems likely), the magnitude of this effect may be sufficient to explain the apparent anti-correlation between $κ_{500}$ and $Σ_{\rm ISM}$. Therefore there may not be any need for spatial variation in the intrinsic dust properties that run counter to theoretical expectations.
