arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2004.11620astro-ph.GA
收藏

Illustris-1和TNG100模拟中的棒星系

Barred galaxies in the Illustris-1 and TNG100 simulations

Ze-Bang Zhou, Weishan Zhu, Yang Wang, Long-Long Feng

摘要:

我们在Illustris-1和TNG 100模拟中对杆结构进行了比较研究。在$z=0$观测中,在1232个具有恒星质量$>10^{10.5}M_{\odot}$的盘星系中,有8.9%的星系是棒斑星系,而在TNG 100观测中,有55%的星系是棒斑星系。TNG 100的杆分数作为恒星质量的函数与$S^4G$的调查结果吻合得很好。在TNG 100和Illustris-1中,棒状体形成的中位红移分别为$\sim 0.4-0.5$和$\sim 0.25$。在这两个模拟中,棒分数一般随恒星质量增加而增加,随气体分数减少。棒星系在高红移处有较高的气体含量,形成棒的时间较晚。当棒形成时,圆盘气体分数大多低于0.4。TNG 100中高得多的棒组分可能得益于自$z\sim3$以来大质量盘星系中低得多的气体组分,这可能是更有效的恒星反馈和活动星系核反馈相结合的结果。后者可能是$z<2$的主要因素。同时,在两个模拟中,棒星系在棒形成前都有较高的恒星形成速率,活动星系核反馈始终比非棒星系强。大质量盘星系的暗物质晕的性质在两个模拟中是相似的,并且对不同的棒频率应该有很小的影响。对于相似晕环境下的单个星系,不同的重子物理条件会导致两种模拟结果在形态上的显著差异。单个星系的形态受到环境和内部重子物理的综合影响,并且通常是不可预测的。

英文摘要:

We carry out a comparison study on the bar structure in the Illustris-1 and TNG100 simulations. At $z=0$, 8.9\% of 1232 disc galaxies with stellar mass $>10^{10.5}M_{\odot}$ in Illustris-1 are barred, while the numbers are 55\% of 1269 in TNG100. The bar fraction as a function of stellar mass in TNG100 agrees well with the survey $S^4G$. The median redshift of bar formation are $\sim 0.4-0.5$ and $\sim 0.25$ in TNG100 and Illustris-1 respectively. Bar fraction generally increases with stellar mass and decreases with gas fraction in both simulations. Barred galaxy had higher gas fraction at high redshift tend to form bar later. When the bars were formed, the disc gas fractions were mostly lower than 0.4. The much higher bar fraction in TNG100 probably have benefit from much lower gas fraction in massive disc galaxies since $z\sim3$, which may result from the combination of more effective stellar and AGN feedback. The latter may be the primary factor at $z<2$. Meanwhile, in both simulations, barred galaxies have higher star formation rate before bar formation, and stronger AGN feedback all the time than unbarred galaxies. The properties of dark matter halos hosting massive disc galaxies are similar between two simulations, and should have minor effect on the different bar frequency. For individual galaxies under similar halo environment cross two simulations, different baryonic physics can lead to striking discrepancy on morphology. The morphology of individual galaxies is subject to combined effects of environment and internal baryonic physics, and is often not predictable.

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。

↑