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arXiv 1703.06002astro-ph.GA
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星系-卫星相互作用对棒形成的影响

Effects of galaxy--satellite interactions on bar formation

R. Moetazedian, E. V. Polyachenko, P. Berczik, A. Just

摘要:

目标。我们的目标是显示如何遇到低质量的卫星星系可能会改变酒吧的形成在银河系般的盘星系。方法.我们使用高分辨率的N体模拟盘星系倾向于轻度酒吧不稳定。对于现实的卫星初始条件,我们利用银河系的暗物质晕的宇宙学模拟。结果卫星可能对砂坝的形成时间有重大影响。一些卫星运行显示出延迟,而另一些则显示出与孤立运行相比棒形成的进步,这种时间差达到$\sim$ 1 Gyr。同时,最终的酒吧配置,包括它的外观和酒吧的特点,如图案的速度和指数增长率的振幅是独立的遭遇的数量和他们的轨道。质量低于$10^9 M_{\odot}$的卫星的贡献是微不足道的,除非它们的近心点距离很小。我们认为,间接的遭遇行为,通过诱导扰动整个光盘,发展到延迟波的中心部分和干扰新兴的种子酒吧。对于现在的宿主星系,预测的效应在红移$z \gtrsim 0.5$上会更加显著。

英文摘要:

Aims. We aim to show how encounters with low-mass satellite galaxies may alter the bar formation in a Milky Way-like disc galaxy. Methods. We use high-resolution N-body simulations of a disc galaxy prone to mild bar instability. For realistic initial conditions of satellites, we take advantage of cosmological simulations of Milky Way-like dark matter haloes. Results. The satellites may have a significant impact on the time of bar formation. Some runs with satellites demonstrate a delay, while others show an advancement in bar formation compared to the isolated run, with such time differences reaching $\sim$ 1 Gyr. Meanwhile, the final bar configuration, including its very appearance and the bar characteristics such as the pattern speed and the exponential growth rate of its amplitude are independent of the number of encounters and their orbits. The contribution of satellites with masses below $10^9 M_{\odot}$ is insignificant, unless their pericentre distances are small. We suggest that the encounters act indirectly via inducing perturbations across the disc that evolve to delayed waves in the central part and interfere with an emerging seed bar. The predicted effect for the present-day host galaxy is expected to be even more significant at redshifts $z \gtrsim 0.5$.

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