论文标题
气体分数和反馈在银河盘的稳定性和演变中的作用：对宇宙星系形成模型的影响
The role of gas fraction and feedback in the stability and evolution of galactic discs: implications for cosmological galaxy formation models
论文作者
论文摘要
高红移星形星系通常具有不规则的形态，{\ it巨大团块}含有高达$ 10^{8-9} $太阳能气体和星星的太阳能。巨型团块的起源和演变在理论上和观察方面都进行了争论。在大多数宇宙学模拟中，高红移星系具有常规的螺旋结构或短寿命的团块，这与许多理想化的高红色速度模型矛盾。在这里，我们测试了这种差异是否可以通过宇宙学模拟中星系的低气压分数来解释。我们提供了一系列具有不同气体分数的模拟，从大多数宇宙学模拟中的25 \％，典型的星系模拟到50 \％，典型的观察到的星系为1.5 <z <3。我们发现气体势型具有短寿命的团块，这些团块是不合时宜的，并且大部分被银河shartic sharactic shearear sharactic shearear kintellar shearear bectellar shearar fiff fiff nefflectic shearar bectellar farearrar farex farefeck。相比之下，即使有增强的恒星反馈，富含气体的模型也会形成长寿命的团块。这表明气体质量分数是驱动暴力碟片不稳定性的主要物理参数，并且在$ \ sim $ \ sim $ 10 $^8 $〜yr timesscales上的巨大团块的演变，其校准恒星反馈的校准影响较低。银河形成的许多宇宙学模拟都具有相对贫困的银河系盘，这可以解释为什么在此类模型中不存在或短暂的巨型团块。如果气体分数与观测更好一致，类似的重型和暗物质质量分布可能会产生$ z \ sim2 $的块状星系。
High-redshift star-forming galaxies often have irregular morphologies with {\it giant clumps} containing up to $10^{8-9}$ solar masses of gas and stars. The origin and evolution of giant clumps are debated both theoretically and observationally. In most cosmological simulations, high-redshift galaxies have regular spiral structures or short-lived clumps, in contradiction with many idealised high-redshift disc models. Here we test whether this discrepancy can be explained by the low gas fractions of galaxies in cosmological simulations. We present a series of simulations with varying gas fractions, from 25\%, typical of galaxies in most cosmological simulations, to 50\%, typical of observed galaxies at 1.5 < z < 3. We find that gas-poor models have short-lived clumps, that are unbound and mostly destroyed by galactic shear, even with weak stellar feedback. In contrast, gas-rich models form long-lived clumps even with boosted stellar feedback. This shows that the gas mass fraction is the primary physical parameter driving violent disc instabilities and the evolution of giant clumps on $\sim$10$^8$~yr timescales, with lower impact from the calibration of the stellar feedback. Many cosmological simulations of galaxy formation have relatively gas-poor galactic discs, which could explain why giant clumps are absent or short-lived in such models. Similar baryonic and dark matter mass distribution could produce clumpy galaxies with long-lived clumps at $z\sim2$ if the gas fraction was in better agreement with observations.
