The Heating of Mid-Infrared Dust in the Nearby Galaxy M33: A Testbed for Tracing Galaxy Evolution
M. Calapa, D. Calzetti, B. T. Draine, M. Boquien, C. Kramer, M. Xilouris, S. Verley, J. Braine, M. Relaño-Pastor, P. van der Werf, F. Israel, I. Hermelo, M. Albrecht
Because the 8 μm polycyclic aromatic hydrocarbon (PAH) emission has been found to correlate with other well-known star formation tracers, it has widely been used as a star formation rate (SFR) tracer. There are, however, studies that challenge the accuracy and reliability of the 8 μm emission as a SFR tracer. Our study, part of the Herschel M33 Extended Survey (HERM33ES) open time key program, aims at addressing this issue by analyzing the infrared emission from the nearby spiral galaxy M33 at the high spatial scale of 75 pc. Combining data from the Herschel Space Observatory and the Spitzer Space Telescope we find that the 8 μm emission is better correlated with the 250 μm emission, which traces cold interstellar gas, than with the 24 μm emission. The L(8)/L(24) ratio is highly depressed in 24 μm luminous regions, which correlate with known HII regions. We also compare our results with the dust emission models by Draine & Li (2007). We confirm that the depression of 8 μm PAH emission near star-forming regions is higher than what is predicted by models; this is possibly an effect of increased stellar radiation from young stars destroying the dust grains responsible for the 8 μm emission as already suggested by other authors. We find that the majority of the 8 μm emission is fully consistent with heating by the diffuse interstellar medium, similar to what recently determined for the dust emission in M31 by Draine at al. (2013). We also find that the fraction of 8 μm emission associated with the diffuse interstellar radiation field ranges between 60% and 80% and is 40% larger than the diffuse fraction at 24 μm.
Origins of complex organic molecules in L1551 IRS 5: Interplay of thermal heating and accretion shocks
Korea Astronomy and Space Science Institute（韩国天文与空间科学研究院）；Department of Physics and Astronomy, Seoul National University（首尔大学物理与天文学系）；Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University（鹿儿岛大学理工学研究科物理与天文学系）；Academia Sinica Institute of Astronomy & Astrophysics（中央研究院天文及天文物理研究所）
Tree-based solvers for adaptive mesh refinement code FLASH -- III: a novel scheme for radiation pressure on dust and gas and radiative transfer from diffuse sources
Temperature structure and kinematics of the IRDC G035.39-00.33
目的。红外暗云代表了大质量恒星形成的最早阶段。需要在所有物理尺度上详细观察它们的物理条件，以提高我们对它们在恒星形成中的作用的理解。方法.我们用经典的氨温度计探测稠密气体，研究了IRDC G 035.39 -00.33的大尺度结构。这使我们能够对扩展的pc级致密气藏的温度进行可靠的约束，并探测其非热运动的幅度。可用的远红外观测值可与观测到的氨排放量结合使用，以估算G035.39-00.33中所含的总气体质量。结果我们确定了一个主要的速度分量作为一个突出的灯丝，表现为氨排放强度脊跨越超过6 pc，与以前的研究云的北部。一些额外的视线组件被发现，和一个大规模的，线性速度梯度~0.2公里秒$^{-1}$ PC $^{-1}$被发现沿脊的IRDC。与尘埃温度图相反，氨衍生的动力学温度图，为整个云，揭示了当地的温度增强对大规模的原恒星核心。我们表明，没有适当考虑视线污染，粉尘温度是2-3 K大于NH $_3$测量的气体温度。结论.虽然大尺度的运动学和温度结构与无星暗丝一致，但小尺度上的动力学气体温度分布暗示着追踪与大质量原恒星核位置一致的加热机制。
Simulator of Galaxy Millimeter/Submillimeter Emission (SIGAME): The [CII]-SFR Relationship of Massive z=2 Main Sequence Galaxies
我们目前的[CII]157.7 $μ$精细结构线发射的宇宙学平滑粒子流体动力学（SPH）模拟在z=2的七个主序星星系的SNORGGAME模拟。使用亚网格物理处方的气体在我们的模拟被建模为一个多相的星际介质（ISM）的分子气体居住在巨大的分子云，与光离解区（PDR）在云表面的原子气相，和扩散，电离的气相。采用logotropic云密度分布和占加热的本地FUV辐射场和宇宙射线的缩放与本地恒星形成率（SFR）的体积密度，我们计算的[CII]发射使用光子逃逸概率形式主义。[CII]的发射峰值位于我们星系中心的$\lesssim$ 1 kpc，SFR径向轮廓也是如此，其中大多数[CII]（$\gtrsim$ 70%）起源于分子气相，而在更远的地方（$\gtrsim$ 2 kpc），原子/PDR气体占主导地位（$\gtrsim$ 90%）[CII]的发射，不再追踪正在进行的恒星形成。在整个过程中，电离气体的贡献可忽略不计（$\lesssim$ 3%）。[CII]光度与SFR（[CII]-SFR）的关系，集成以及空间分辨（尺度为1千秒差距），描绘了我们的模拟星系是在良好的协议与当地观察到的相应关系，并在高红移。在我们的模拟中，分子气体在SFR $\gtrsim$ 20 M $_{\odot}$ yr $^{-1}$（SFR密度$\gtrsim$ 0.5 M $_{\odot}$ yr $^{-1…
