arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1503.01468astro-ph.GAastro-ph.CO
收藏

冲压压力和合并对恒星形成和汽提分数的协同影响

The collaborative effect of ram pressure and merging on star formation and stripping fraction

Jan Christoph Bischko, Dominik Steinhauser, Sabine Schindler

摘要:

目的:研究冲压压力剥离(RPS)对富气旋涡星系并合对模拟的影响。我们的目标是提供合并和RPS对剥离效率和恒星形成率的综合影响的估计。方法:我们使用组合N体/流体动力学代码GADGET-2。在我们的模拟中,我们在二元合并中将质量比在1:4和1:8之间变化。我们采样不同的几何构型的合并系统(边缘和面对合并,不同的碰撞参量)。此外,我们粗略地改变了团内介质(ICM)的性质:合并系统相对于ICM的速度在500和1000 km/s之间,ICM密度在$10^{-29}$和$10^{-27}$ g/cm $^3$之间,ICM相对于合并轨道平面的方向。在模拟时间段内,柱塞压力保持恒定,ICM温度也保持恒定,即$10^7$ K。ICM中的每个模拟都与真空中的合并和具有作用冲压压力的非合并星系的模拟进行了比较。结果如下:在模拟时间(1 Gyr)的合并对平均显示了一个可以忽略不计的5%的SFR增强,在相同的环境条件下相比,单个星系。SFR在星系第一次飞越时达到峰值。在那里,我们的模拟显示SFR高达20 M $_{\odot}$ /年(相比之下,3 M $_{\odot}$ /年的非合并星系在真空中)。在最极端的情况下,这构成了一个短期($<50$百万年)SFR增加50%的非合并星系经历冲压压力。ICM中合并星系的尾流通常具有非合并星系中恒星质量的三分之一到一半,气体质量少5%到10%。根据我们的模拟,RPS和合并的联合效应与纯冲压压力效应没有显著差异。

英文摘要:

Aims: We investigate the effect of ram pressure stripping (RPS) on simulations of merging pairs of gas-rich spiral galaxies. Our goal is to provide an estimate of the combined effect of merging and RPS on stripping efficiency and star formation rate. Methods: We make use of the combined N-body/hydrodynamic code GADGET-2. In our simulations, we vary mass ratios between 1:4 and 1:8 in a binary merger. We sample different geometric configurations of the merging systems (edge-on and face-on mergers, different impact parameters). Furthermore, we vary the properties of the intracluster medium (ICM) in rough steps: The speed of the merging system relative to the ICM between 500 and 1000 km/s, the ICM density between $10^{-29}$ and $10^{-27}$ g/cm$^3$, and the ICM direction relative to the mergers' orbital plane. Ram pressure is kept constant within a simulation time period, as is the ICM temperature of $10^7$ K. Each simulation in the ICM is compared to simulations of the merger in vacuum and the non-merging galaxies with acting ram pressure. Results: Averaged over the simulation time (1 Gyr) the merging pairs show a negligible 5% enhancement in SFR, when compared to single galaxies under the same environmental conditions. The SFRs peak at the time of the galaxies first fly-through. There, our simulations show SFRs of up to 20 M$_{\odot}$/yr (compared to 3 M$_{\odot}$/yr of the non-merging galaxies in vacuum). In the most extreme case, this constitutes a short-term ($<50$ Myr) SFR increase of 50% over the non-merging galaxies experiencing ram pressure. The wake of merging galaxies in the ICM typically has a third to half the star mass seen in the non-merging galaxies and 5% to 10 % less gas mass. The joint effect of RPS and merging, according to our simulations, is not significantly different from pure ram pressure effects.

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。

↑