论文标题
高红移星系中尘埃温度和质量的辐射平衡估计值
Radiative equilibrium estimates of dust temperature and mass in high-redshift galaxies
论文作者
论文摘要
估计高$ z $星系中的灰尘的温度和质量对于讨论早期宇宙中尘埃的起源至关重要。但是，这遭受了红外光谱 - 能源分布的采样有限。在这里，我们提出了一种用于推导银河系温度和灰尘质量的算法，假设灰尘处于辐射平衡状态。我们为三个几何形式制定算法：一个薄的球形外壳，一个均匀的球体和一个笨拙的球体。我们还讨论了紫外线和红外波长的质量吸收系数，分别分别为$κ_ {\ rm UV} $和$κ_ {\ rm ir} $。例如，我们将算法应用于$ z = 7.5 $，a1689zd1的普通，尘土飞扬的星系，为此，可以在灰尘连续体中提供三个数据点。使用$κ_ {\ rm uv} = 5.0 \ times10^4 $ cm $^2 $ g $^{ - 1} $和$κ_ {\ rm ir} = 30（λ/100μm）^{ - β{ - β} $ cm $ $ cm $ g $ g $ g $ g $ g $^{ - 1} $^{ - 1} $ with $ k＆β= 2.0 suft $β= 2.0 putd tuck ycut duck和β= 2.0 $ 10^{6.5-7.3} $ m $ _ \ odot $用于所考虑的三个几何$。我们从灰尘连续体的一个数据点获得类似的温度和质量，这表明该算法对高$ z $星系的有用性具有有限的红外观测值。在笨拙的情况下，温度变得等于通常修饰的黑体拟合的温度，因为描述块状的附加参数是调节器。最佳拟合团块参数为$ξ_ {\ rm cl} = 0.1 $，对应于$ \ sim10 $ \％，如果团块大小为$ \ sim10 $ PC，则在此高$ z $ galaxy中的团块填充因子的体积填充因子的数量，类似于本地世界中的巨型分子云。
Estimating the temperature and mass of dust in high-$z$ galaxies is essential for discussions of the origin of dust in the early Universe. However, this suffers from limited sampling of the infrared spectral-energy distribution. Here we present an algorithm for deriving the temperature and mass of dust in a galaxy, assuming dust to be in radiative equilibrium. We formulate the algorithm for three geometries: a thin spherical shell, a homogeneous sphere, and a clumpy sphere. We also discuss effects of the mass absorption coefficients of dust at ultraviolet and infrared wavelengths, $κ_{\rm UV}$ and $κ_{\rm IR}$, respectively. As an example, we apply the algorithm to a normal, dusty star-forming galaxy at $z=7.5$, A1689zD1, for which three data points in the dust continuum are available. Using $κ_{\rm UV}=5.0\times10^4$ cm$^2$ g$^{-1}$ and $κ_{\rm IR}=30(λ/100μm)^{-β}$ cm$^2$ g$^{-1}$ with $β=2.0$, we obtain dust temperatures of 38--70~K and masses of $10^{6.5-7.3}$ M$_\odot$ for the three geometries considered. We obtain similar temperatures and masses from just a single data point in the dust continuum, suggesting the usefulness of the algorithm for high-$z$ galaxies with limited infrared observations. In the clumpy-sphere case, the temperature becomes equal to that of the usual modified black-body fit, because an additional parameter describing the clumpiness works as an adjuster. The best-fit clumpiness parameter is $ξ_{\rm cl}=0.1$, corresponding to $\sim10$\% of the volume filling factor of the clumps in this high-$z$ galaxy if the clump size is $\sim10$ pc, similar to that of giant molecular clouds in the local Universe.
