论文标题
高Z星系中的温暖灰尘：起源和含义
Warm dust in high-z galaxies: origin and implications
论文作者
论文摘要
阿尔玛（Alma）的观察结果表明，在电离时期（红移$ z> 6 $）中存在灰尘。但是，灰尘温度（$ t_d $）仍然不受限制，这引入了大型不确定性，尤其是在尘埃质量测定中。使用分析性和物理动机的模型，我们表明，高$ z $的灰尘，形成星形的巨型分子云（GMC），在很大程度上主导了观察到的远红外发光度，比本地的灰尘更暖（$ t_d> 60> 60> 60 \ \ \ \ \ \ m rastrm {k} $）。这是由于表征早期星系的较高气压和湍流引起的更紧凑的GMC结构。紧凑性还延迟了恒星反馈的GMC散布，因此，新出生的恒星发出的紫外线辐射的$ \ sim 40 \％$仍然被遮盖了。更高的$ t_d $具有其他含义：（a）减少本地和高$ z $ irx-$β$关系之间的张力，（b）减轻了从某些EOR星系中观察到的不舒服的大灰尘质量的问题。
ALMA observations have revealed the presence of dust in galaxies in the Epoch of Reionization (redshift $z>6$). However, the dust temperature, $T_d$, remains unconstrained, and this introduces large uncertainties, particularly in the dust mass determinations. Using an analytical and physically-motivated model, we show that dust in high-$z$, star-forming giant molecular clouds (GMC), largely dominating the observed far-infrared luminosity, is warmer ($T_d > 60\ \mathrm{K}$) than locally. This is due to the more compact GMC structure induced by the higher gas pressure and turbulence characterizing early galaxies. The compactness also delays GMC dispersal by stellar feedback, thus $\sim 40\%$ of the total UV radiation emitted by newly born stars remains obscured. A higher $T_d$ has additional implications: it (a) reduces the tension between local and high-$z$ IRX-$β$ relation, (b) alleviates the problem of the uncomfortably large dust masses deduced from observations of some EoR galaxies.
