Formation of Our Galaxy Studied with Super-High Resolution Next-Generation Simulator

使用超高分辨率下一代模拟器研究银河系的形成

基本信息

批准号：
17340059
负责人：
TOMISAKA Kohji
金额：
$ 8.54万
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 (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

1. We completed (1) a parallelized N-body plus SPH hydro code called ASURA and (2) a PC cluster composed of 16 PC's each connected with a specific hardware for self-gravity (GRAPE). Since these enable us to study the formation process of our Galaxy, we call them Milky Way Simulator (MWS).(1) We perform high resolution simulations with MWS, in which one galaxy is expressed with 10^7 particles, which is much larger than previous similar simulations. From them, we can trace the condensation process of interstellar gas to form stars up to〜10^2cm-3, which coincides with the density of molecular clouds in our Galaxy.(2) A phenomenological parameter, C_<eff>, has been assumed, with which the star formation rate per unit volume is assumed as C^<eff>_<eff>×ρ_<gas>/t_<ff>, where>_<gas> as and t_<ff> represent, respectively, the local gas density and free-wall timescale of the gas. Our high resolution simulations indicate us that the star formation rate is well expressed with a radiative cooling time of a gas with a density of 10^0cm_<-3>, irrespective of C_<eff>.(3) Thus, we obtained a prescription how to manage the star formation in low resolution simulations.(4) We performed simulations of galaxy-galaxy collision. We found that a star formation burst is expected in the early phase of the collision far before making a galaxy merger.2. We developed an adaptive mesh refinement (AMR) code for self-gravitating magnetohydrodynamical simulation based on the finite-difference scheme. Calculating the fragmentation process in the protostellar phase, we have confirmed that this code gives the consistent result obtained with previous nested grid code. This enables us to extend the subjects.3. To compare the simulation result with observation, we have developed a radiative transfer code for molecular rotational transitions based on Monte Carlo method. We have applied this to starburst galaxy and star forming molecular cloud.

1。我们完成了（1）一个并行的N体加上SPH Hydro Code，称为Asura和（2）一个由16个PC组成的PC群集，每个PC都与特定的硬件（葡萄）相连。由于这些使我们能够研究银河系的形成过程，因此我们称它们为银河系模拟器（MWS）。（1）我们用MWS执行高分辨率模拟，其中一个星系用10^7粒子表达，这比以前的类似模拟大得多。 From them, we can trace the condensation process of interstellar gas to form stars up to ~10^2cm-3, which coincides with the density of molecular clouds in our Galaxy.(2) A phenomenological parameter, C_<eff>, has been assumed, with which the star formation rate per unit volume is assumed as C^<eff>_<eff>×ρ_<gas>/t_<ff>,其中> _ <gas> as和t_ <ff>分别表示气体的局部气体密度和自由壁时间尺度。我们的高分辨率模拟表明我们，恒星形成速率通过辐射冷却时间，密度为10^0 cm _ <-3>，不论C_ <eff>。在进行银河合并之前碰撞2。我们开发了一种基于有限差分方案的自适应网状细化（AMR）代码，用于自我磨碎的磁流体动力学模拟。在原始阶段计算碎裂过程，我们已经确认该代码给出了以前的嵌套网格代码获得的一致结果。这使我们能够扩展主题3。为了将模拟结果与观察结果进行比较，我们开发了基于蒙特卡洛方法的分子旋转转变的辐射传递代码。我们已将其应用于Starburst Galaxy和Star形成分子云。