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arXiv 2302.07882astro-ph.COastro-ph.GAastro-ph.HE
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重子在自相互作用暗物质并合中的作用

The role of baryons in self-interacting dark matter mergers

Moritz S. Fischer, Nils-Henrik Durke, Katharina Hollingshausen, Claudius Hammer, Marcus Brüggen, Klaus Dolag

AI总结:

本文通过SPH+N体模拟研究星系团并合中ICM对暗物质-星系偏移的影响,发现ICM在第一次远心点可放大偏移,且较小自相互作用截面也可能产生可观测偏移,表明后期并合阶段对暗物质物理研究更具价值。

摘要:

星系团并合是探测暗物质物理的有前景的探针。例如,暗物质成分与星系分布之间的偏移可以约束暗物质自相互作用。我们研究星系团内介质(ICM)的作用及其在自相互作用暗物质模型中对暗物质-星系偏移的影响。为此,我们采用平滑粒子流体动力学+N体模拟来研究正面碰撞的等质量和不等质量并合的理想化设置。我们的模拟表明,与仅含暗物质的模拟相比,ICM几乎不影响第一次近心点通过后不久产生的偏移。但在之后,例如在第一次远心点,ICM的存在可以放大偏移。此外,我们发现小到不会被弛豫星系团核心尺寸测量所排除的截面有机会产生可观测的偏移。我们发现不同的暗物质模型会影响暗物质分布,也会影响星系和ICM分布,包括其温度。潜在地,激波前沿的位置与最亮团星系相结合,可以为暗物质的性质提供进一步的线索。总体而言,我们的结果表明,处于第一次远心点通过前后阶段的星系团并合在暗物质物理方面可能比第一次近心点通过后不久的并合更有趣。这可能推动对更晚演化阶段并合的进一步研究。

英文摘要:

Mergers of galaxy clusters are promising probes of dark matter (DM) physics. For example, an offset between the DM component and the galaxy distribution can constrain DM self-interactions. We investigate the role of the intracluster medium (ICM) and its influence on DM-galaxy offsets in self-interacting dark matter models. To this end, we employ Smoothed Particle Hydrodynamics + N-body simulations to study idealized setups of equal- and unequal-mass mergers with head-on collisions. Our simulations show that the ICM hardly affects the offsets arising shortly after the first pericentre passage compared to DM-only simulations. But later on, e.g. at the first apocentre, the offsets can be amplified by the presence of the ICM. Furthermore, we find that cross-sections small enough not to be excluded by measurements of the core sizes of relaxed galaxy clusters have a chance to produce observable offsets. We found that different DM models affect the DM distribution and also the galaxy and ICM distribution, including its temperature. Potentially, the position of the shock fronts, combined with the brightest cluster galaxies, provides further clues to the properties of DM. Overall our results demonstrate that mergers of galaxy clusters at stages about the first apocentre passage could be more interesting in terms of DM physics than those shortly after the first pericentre passage. This may motivate further studies of mergers at later evolutionary stages.

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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