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arXiv 1309.2437astro-ph.GA
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棒支配盘星系中的径向迁移I:对化学演化的影响

Radial migration in a bar-dominated disk galaxy I: Impact on chemical evolution

M. Kubryk, N. Prantzos, E. Athanassoula

摘要:

通过分析一个完全自洽的高分辨率N体+SPH模拟的结果,我们研究了棒控盘星系的径向迁移和化学演化。我们发现气体和恒星粒子有不同的行为。在共转的气体驱动的酒吧,在那里它形成一个伪隆起(盘状隆起)的中心区域,但它经历了酒吧区域外的径向位移可以忽略不计。恒星在任何时候都经历着大量的径向迁移,首先是由短暂的旋臂引起的,后来是由棒引起的。尽管在我们的模型中发生了大量的径向迁移,但其对化学性质的影响是有限的。原因是由于整个盘的快速早期演化,丰度分布相对平坦。我们表明,径向迁移对化学演化的影响,可以研究到一个很好的精度后处理的N-体+SPH计算的结果与一个简单的化学演化模型,具有详细的化学和径向迁移的参数化描述。我们发现,径向迁移影响化学演化的直接(通过移动周围的核合成的长寿代理,如SNIa或AGB星,从而改变丰度配置文件的气体)和间接(通过移动周围的长寿示踪剂的化学演化,从而影响恒星的金属丰度配置文件,本地年龄金属丰度关系和恒星的金属丰度分布等)。

英文摘要:

We study radial migration and chemical evolution in a bar-dominated disk galaxy, by analyzing the results of a fully self-consistent, high resolution N-body+SPH simulation. We find different behaviours for gas and star particles. Gas within corotation is driven in the central regions by the bar, where it forms a pseudo-bulge (disky-bulge), but it undergoes negligible radial displacement outside the bar region. Stars undergo substantial radial migration at all times, caused first by transient spiral arms and later by the bar. Despite the important amount of radial migration occurring in our model, its impact on the chemical properties is limited. The reason is the relatively flat abundance profile, due to the rapid early evolution of the whole disk. We show that the implications of radial migration on chemical evolution can be studied to a good accuracy by post-processing the results of the N-body+SPH calculation with a simple chemical evolution model having detailed chemistry and a parametrized description of radial migration. We find that radial migration impacts on chemical evolution both directly (by moving around the long-lived agents of nucleosynthesis, like e.g. SNIa or AGB stars, and thus altering the abundance profiles of the gas) and indirectly (by moving around the long-lived tracers of chemical evolution and thus affecting stellar metallicity profiles, local age-metallicity relations and metallicity distributions of stars, etc.).

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。

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