arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1208.3698astro-ph.CO
收藏

第一个Galerkin:在第一颗恒星辐射反馈下的组装

The First Galaxies: Assembly under Radiative Feedback from the First Stars

Andreas H. Pawlik, Milos Milosavljevic, Volker Bromm

摘要:

我们研究如何辐射反馈的第一个恒星影响的第一个矮星系的组装。我们对一个矮星系在z = 10时聚集在一个维里质量为10^9太阳的晕内进行了宇宙学放大SPH模拟。模拟遵循原始气体的非平衡化学/冷却以及气体转化为无金属恒星。为了量化的辐射反馈,我们比较模拟中,恒星发出分子氢离解和氢/氦电离辐射与模拟中,恒星只发出离解辐射,并与模拟中,恒星保持黑暗。光解离和光电离对模拟星系的组装有很强的负反馈作用.与模拟中恒星保持黑暗的情况相比,气体冷凝受到强烈阻碍,恒星形成受到强烈抑制。对气体的反馈意味着抑制的中心暗物质密度在minihalo祖的几个因素,这是一个显着的偏离奇异的等温密度分布特征的暗物质分布在没有辐射反馈。气体密度、恒星形成速率和暗物质分布的演化在小晕组装的后期阶段对电离辐射的存在变得不敏感,一旦小晕转变为原子冷却的星系,对电离辐射的存在变得不敏感。在矮星系内部形成的扩展盘是一个不受辐射影响的强大结果。我们估计,像这里模拟的矮星系将是即将到来的詹姆斯韦伯太空望远镜将探测到的最微弱的星系之一。我们的结论是受我们忽视的反馈超新星和化学富集以及宇宙的变化。[删节]

英文摘要:

We investigate how radiative feedback from the first stars affects the assembly of the first dwarf galaxies. We perform cosmological zoomed SPH simulations of a dwarf galaxy assembling inside a halo of virial mass 10^9 solar at z = 10. The simulations follow the non-equilibrium chemistry/cooling of primordial gas and the conversion of the gas into metal-free stars. To quantify the radiative feedback, we compare a simulation in which stars emit both molecular hydrogen dissociating and hydrogen/helium ionizing radiation with a simulation in which stars emit only dissociating radiation, and with a simulation in which stars remain dark. Photodissociation and -ionization exert a strong negative feedback on the assembly of the simulated galaxy. Gas condensation is strongly impeded, and star formation is strongly suppressed in comparison with the simulation in which stars remain dark. The feedback on the gas implies a suppression of the central dark matter densities in the minihalo progenitor by factors of up to a few, which is a significant deviation from the singular isothermal density profile characterizing the dark matter distribution in the absence of radiative feedback. The evolution of gas densities, star formation rates, and the distribution of dark matter becomes insensitive to the inclusion of dissociating radiation in the late stages of the minihalo assembly, and it becomes insensitive to the inclusion of ionizing radiation once the minihalo turns into an atomically cooling galaxy. The formation of an extended disk inside the dwarf galaxy is a robust outcome not affected by the inclusion of radiation. We estimate that dwarf galaxies such as simulated here will be among the faintest galaxies the upcoming James Webb Space Telescope will detect. Our conclusions are subject to our neglect of feedback from supernovae and chemical enrichment as well as to cosmic variance. [abridged]

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑