通过宇宙演化模拟研究 Bulge 的形成机制
摘要
最新一代宇宙演化模拟正在解决Bulge结构的能力，因而我们审查了宇宙演化模拟中Bulge形成的当前状态，讨论了在模拟者近期可解决的开放性问题，特别关注由 mergers 驱动的Bulge增长。星系 mergers 长期以来一直被假设为产生盘状星系中的经典Bulge。然而，在该Bulge形成模型下，冷暗物质星系形成理论中对 mergers 的高速率预测，导致比观察到的更多的经典Bulge。此外，星系形成的模拟继续普遍产生过于庞大的Bulge。反馈提供了一条有前景的途径，通过维持星系中高气体分数并喷射被驱动到星系中心的低角动量气体来减少由mergers驱动的Bulge增长。 After reviewing relevant research results published to date, we use cosmological simulations to explore the ability of feedback to reduce or even prevent bulge growth during mergers. In dwarf galaxies, mergers actually reduce the central concentration of galaxies as the induced burst of star formation drives out low angular momentum material. This result shows the potential for feedback to reduce central mass growth. However, we also demonstrate that it is very difficult for current stellar feedback models to reproduce the small bulges observed in more massive disk galaxies like the Milky Way. We argue that feedback models need to be improved, or an additional source of feedback such as AGN is necessary to generate the required outflows.
引用
@article{arxiv.1511.04095,
title = {Bulge Formation via Mergers in Cosmological Simulations},
author = {Alyson M. Brooks and Charlotte R. Christensen},
journal= {arXiv preprint arXiv:1511.04095},
year = {2015}
}
备注
The first 5 sections are review, but Section 6 introduces new analysis. We demonstrate that mergers prevent bulge formation in low mass galaxies. Approximately 15 pages in MNRAS format