Numerical Astronomy using molecular and atomic line transfer calculations in the ALMA-era.

ALMA 时代使用分子和原子线传输计算的数值天文学。

• 批准号: 16204012
• 负责人: MIYAMA Shoken
• 金额: $ 29.29万
• 依托单位: National Astronomical Observatory of Japan
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16204012/
• 关键词: Numerical Simulation; Radiative Transfer; Interstellar matter; 活動銀河核; 原始銀河

We explore millimeter line diagnostics of an obscuring molecular torus modeled by a hydrodynamic simulation with three-dimensional non-local thermodynamic equilibrium radiative transfer calculations. Based on the results of a high-resolution hydrodynamic simulation of the molecular torus around an active galactic nucleus, we calculate the intensities of the HCN and HCO+ rotational lines as two representative high-density tracers. Three-dimensional radiative transfer calculations shed light on a complicated excitation state in the inhomogeneous torus, even though a spatially uniform chemical structure is assumed. We find that similar transition coefficients for the HCN and HCO+ rotational lines lead to a natural concordance of the level population distributions of these molecules and a line ratio RHCN/HC0+<〜1 for the same molecular abundance value over 2 orders of magnitude. Our results suggest that HCN must be much more abundant than HCO+ (yHCN>〜10yHCO+) in order to obtain the high ratio (RHCN/HCO+-2) observed in some nearby galaxies. There is a remarkable dispersion in the relation between integrated intensity and column density, indicative of possible shortcomings of the HCN (1-0) and HCO+ (1-0) lines as high-density tracers. The internal structures of inhomogeneous molecular tori down to subparsec scales in external galaxies will be revealed by the forthcoming Atacama Large Millimeter/submillimeter Array. Three-dimensional radiative transfer calculations of molecular lines with a high-resolution hydrodynamic simulation prove to be a powerful tool to provide a physical basis for molecular-line diagnostics of the central regions of external galaxies.

我们探索毫米线诊断的一个模糊的分子环面建模的流体动力学模拟与三维非局部热力学平衡辐射传输计算。基于对活动星系核周围分子环的高分辨率流体动力学模拟结果，计算了HCN和HCO+两种代表性高密度示踪剂的转动谱线强度.三维辐射传输计算揭示了一个复杂的激发态的非均匀环，即使是一个空间均匀的化学结构假设。我们发现，HCN和HCO+转动谱线的跃迁系数相似，导致了这两种分子的能级布居分布的自然一致性，并且对于2个数量级以上的相同分子丰度值，RHCN/HCO+的谱线比<1。我们的结果表明，HCN必须比HCO+丰富得多（yHCN> 10 yHCO+），以获得高比率（RHCN/HCO+-2）在一些附近的星系中观察到的。在积分强度和柱密度之间的关系中存在显著的分散性，表明HCN（1-0）和HCO+（1-0）线作为高密度示踪剂可能存在缺点。阿塔卡玛大型毫米/亚毫米阵列将揭示外部星系中亚秒差距尺度的不均匀分子环面的内部结构。分子线的三维辐射传输计算与高分辨率流体动力学模拟被证明是一个强大的工具，提供了一个物理基础的分子线诊断的中心区域的外部星系。

项目成果

Modeling ISM, Star Formation and Feedback in 3-D Galactic Disks

3D 银河盘中的 ISM、恒星形成和反馈建模

• 发表时间: 2008
• 作者: Wada;K.
• 通讯作者: K.

Radiative Transfer and ISM (review talk)

辐射传输和 ISM（回顾演讲）

• 发表时间: 2007
• 作者: M.Haino;4 co-authors;山田雅子
• 通讯作者: 山田雅子

Modeling 3-D ISM in Galactic Disks using Grid and Particle-Based Simulations

使用网格和基于粒子的模拟对银河盘中的 3-D ISM 进行建模

• 发表时间: 2007
• 作者: Pearson;Chris P. ; Jeong;Woong-Seob ; Matsuura;Shuji ; Matsuhara;Hideo ; Nakagawa;Takao ; Shibai;Hiroshi ; Kawada;Mitsunobu ; Takagi;Toshinobu ; Lee;Hyung Mok ; Shirahata;Mai;和田 桂一
• 通讯作者: 和田 桂一

Molecular gas structure around an AGN with nuclear starburst : 3-D Non-LTE calculations of CO lines

具有核星暴的 AGN 周围的分子气体结构：CO 谱线的 3-D 非 LTE 计算

• 发表时间: 2005
• 期刊: The Astrophysical Journal 619
• 作者: Keiichi Wada;Kohji Tomisaka
• 通讯作者: Kohji Tomisaka

Formation of Massive Primordial Stars in a Reionized Gas

• DOI: 10.1086/522202
• 发表时间: 2007-06
• 期刊: The Astrophysical Journal Letters
• 作者: Naoki Yoshida;K. Omukai;L. Hernquist