On the dust temperatures of high-redshift galaxies
On the dust temperatures of high-redshift galaxies
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DOI：
10.1093/mnras/stz2134
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发表时间：
2019-02
影响因子：
4.8
通讯作者：
Lichen Liang;R. Feldmann;D. Keres̆;N. Scoville;C. Hayward;C. Faucher-Giguère;C. Schreiber;Xiangcheng Ma;P. Hopkins;E. Quataert
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文献类型：
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作者：
Lichen Liang;R. Feldmann;D. Keres̆;N. Scoville;C. Hayward;C. Faucher-Giguère;C. Schreiber;Xiangcheng Ma;P. Hopkins;E. Quataert
尘埃温度是星系星际介质的一个重要性质。在高红移星系中，将（亚）毫米宽带通量转换为总红外光度（LIR），从而转换为星星形成率时，需要它。然而，文献中使用了不同的尘埃温度定义，导致对ISM条件如何随着红移和星星形成率等变化而变化的不同物理解释。本文利用真实环境反馈（Fire）计划中的高分辨率宇宙学模拟，分析了大质量（$M_{\rm星星} \gt 10^{10}\，\mathrm{M}_{\odot }$）z$ = 2-6星系的尘埃温度。在$z $102，我们的模拟成功地预测了尘埃温度与观测结果吻合良好。我们发现，尘埃温度的基础上的峰值发射波长增加的红移，符合较高的星星形成活动在较高的红移，并与特定的星星形成率强相关。与此相反，质量加权的尘埃温度，这是需要准确地估计总尘埃质量，不强烈的红移超过$z$ = 2-6在固定的红外光度，但密切相关的LIR在固定的$z$。我们还分析了一个“等效”尘埃温度转换（分）毫米通量密度的总红外光度，并提供了一个拟合公式作为红移和尘埃金属比的函数。我们发现，较高的等效（或较高的峰值）尘埃温度（“温暖的尘埃”）的星系不一定有较高的质量加权温度。星际尘埃的“两相”图像可以解释各种尘埃温度的不同标度关系。
Dust temperature is an important property of the interstellar medium (ISM) of galaxies. It is required when converting (sub)millimetre broad-band flux to total infrared luminosity (LIR), and hence star formation rate, in high-redshift galaxies. However, different definitions of dust temperatures have been used in the literature, leading to different physical interpretations of how ISM conditions change with, e.g. redshift and star formation rate. In this paper, we analyse the dust temperatures of massive ($M_{\rm star} \gt 10^{10}\, \mathrm{M}_{\odot }$) $z$ = 2–6 galaxies with the help of high-resolution cosmological simulations from the Feedback in Realistic Environments (fire) project. At $z$ ∼ 2, our simulations successfully predict dust temperatures in good agreement with observations. We find that dust temperatures based on the peak emission wavelength increase with redshift, in line with the higher star formation activity at higher redshift, and are strongly correlated with the specific star formation rate. In contrast, the mass-weighted dust temperature, which is required to accurately estimate the total dust mass, does not strongly evolve with redshift over $z$ = 2–6 at fixed IR luminosity but is tightly correlated with LIR at fixed $z$. We also analyse an ‘equivalent’ dust temperature for converting (sub)millimetre flux density to total IR luminosity, and provide a fitting formula as a function of redshift and dust-to-metal ratio. We find that galaxies of higher equivalent (or higher peak) dust temperature (‘warmer dust’) do not necessarily have higher mass-weighted temperatures. A ‘two-phase’ picture for interstellar dust can explain the different scaling relations of the various dust temperatures.