论文标题
高红移星系中尘埃温度的分析模型
Analytic models of dust temperature in high-redshift galaxies
论文作者
论文摘要
我们研究了使用分析模型在某些高红移（$ z> 5 $）星系中观察到的高灰尘温度（$ t_ \ mathrm {dust} \ gtrsim 40 $ k）的物理原因。我们考虑了可以通过分析进行处理的两个模型：辐射传输（RT）模型，{其中$ t_ \ mathrm {dust} $的值的广泛分布被认为是}，而一个tempearture（一个 - $ t $）模型，假设{均匀$ t_ \ t_ \ sutrm {ductrm {dust} $} $} $} $}。这两个极端{用于括起最现实的场景}。我们采用Kennicutt--Schmidt（KS）定律将恒星辐射场与气体表面密度联系起来，并改变尘埃与气体比率。结果，我们的模型能够预测恒星形成速率（$σ_\ mathrm {sfr} $）的表面密度之间的关系或灰尘质量（$σ_\ mathrm {dust} $）和$ t_ \ t_ \ mathrm {dustrm {dust} $。我们表明，在$ z \ gtrsim 5 $中观察到的高$ t_ \ mathrm {dust} $偏爱低尘埃与气体比率（$ \ sillsim 10^{ - 3} $）。与KS定律相比，增强的星形形成为高$ t_ \ mathrm {dust} $提供了另一种说明。只要我们使用Alma带6--8，两种型号（RT和一$ T $）之间的灰尘温度相似。我们还检查了$σ_\ mathrm {sfr} $，$σ_\ mathrm {dust} $和$ t_ \ mathrm {dustrm {dust} $之间的关系，而无需假设KS定律，并确认与$ z> 5 $的实际观察数据的一致性。在One $ t $型号中，我们还检查了一个块状的灰尘分布，该灰尘分布预测较低的$ t_ \ mathrm {dust} $，因为恒星辐射的泄漏。这提高了低灰尘丰度或高星形形成效率的要求，以解释观察到的高$ t_ \ mathrm {dust} $。
We investigate physical reasons for high dust temperatures ($T_\mathrm{dust}\gtrsim 40$ K) observed in some high-redshift ($z>5$) galaxies using analytic models. We consider two models that can be treated analytically: the radiative transfer (RT) model, {where a broad distribution of values for $T_\mathrm{dust}$ is considered}, and the one-tempearture (one-$T$) model, which assumes {uniform $T_\mathrm{dust}$}. These two extremes {serve to bracket the most realistic scenario}. We adopt the Kennicutt--Schmidt (KS) law to relate stellar radiation field to gas surface density, and vary the dust-to-gas ratio. As a consequence, our model is capable of predicting the relation between the surface density of star formation rate ($Σ_\mathrm{SFR}$) or dust mass ($Σ_\mathrm{dust}$) and $T_\mathrm{dust}$. We show that the high $T_\mathrm{dust}$ observed at $z\gtrsim 5$ favour low dust-to-gas ratios ($\lesssim 10^{-3}$). An enhanced star formation compared with the KS law gives an alternative explanation for the high $T_\mathrm{dust}$. The dust temperatures are similar between the two (RT and one-$T$) models as long as we use ALMA Bands 6--8. We also examine the relation among $Σ_\mathrm{SFR}$, $Σ_\mathrm{dust}$ and $T_\mathrm{dust}$ without assuming the KS law, and confirm the consistency with the actual observational data at $z>5$. In the one-$T$ model, we also examine a clumpy dust distribution, which predicts lower $T_\mathrm{dust}$ because of the leakage of stellar radiation. This enhances the requirement of low dust abundance or high star formation efficiency to explain the observed high $T_\mathrm{dust}$.
