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arXiv 1808.01628astro-ph.GA
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论环境对恒星形成星系的影响

On the influence of environment on star forming galaxies

Lizhi Xie, Gabriella De Lucia, David J. Wilman, Matteo Fossati, Peter Erwin, Leonel Gutierrez, Sandesh K. Kulkarni

摘要:

我们使用我们的国家的最先进的半解析模型GALAXY演化和组装(GAEA),和附近星系的观测测量研究的气体含量和气体/恒星盘大小的恒星形成星系的环境的影响。我们分析了卫星的物理性质之间的差异和他们的中央同行,通过匹配的Vmax的主机晕在吸积时间的卫星,确定的起源。我们的模型很好地再现了中心和卫星测量的HI质量,恒星形成区域的大小和恒星半径之间的差异。相比之下,我们的模型预测的分子气体质量和恒星形成率的数据有较大的差异。通过分析中心星系和卫星星系的祖先,我们发现,在吸积后的气体含量的差异出现,可以完全归因于瞬时剥离的热气库。通过冷却和恒星形成抑制冷气补充导致冷气及其密度的降低。因此,与密度较低的HI气体相比,损失了更多的分子气体,并且模型卫星的分子气体和恒星形成率低于观测卫星。我们认为,这些分歧可以在很大程度上得到解决,包括一个适当的治疗冲压压力剥离的冷气体和更渐进的剥离的热气藏。角动量交换的一个更复杂的治疗,占多相性质的气体盘也需要。

英文摘要:

We use our state-of-the-art semi analytic model for GAlaxy Evolution and Assembly (GAEA), and observational measurements of nearby galaxies to study the influence of the environment on the gas content and gaseous/stellar disc sizes of star-forming galaxies. We analyse the origin of differences between physical properties of satellites and those of their central counterparts, identified by matching the Vmax of their host haloes at the accretion time of the satellites. Our model reproduces nicely the differences between centrals and satellites measured for the HI mass, size of the star-forming region, and stellar radii. In contrast, our model predicts larger differences with respect to data for the molecular gas mass and star formation rate. By analysing the progenitors of central and satellite model galaxies, we find that differences in the gas content arise after accretion, and can be entirely ascribed to the instantaneous stripping of the hot gas reservoir. The suppression of cold gas replenishment via cooling and star formation leads to a reduction of the cold gas and of its density. Therefore, more molecular gas is lost than lower density HI gas, and model satellites have less molecular gas and lower star formation rates than observed satellites. We argue that these disagreements could be largely resolved with the inclusion of a proper treatment for ram-pressure stripping of cold gas and a more gradual stripping of the hot gas reservoir. A more sophisticated treatment of angular momentum exchanges, accounting for the multi-phase nature of the gaseous disc is also required.

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