arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 0906.5353astro-ph.CO
收藏

相互作用暗能量宇宙学中结构形成的模拟

Simulations of structure formation in interacting dark energy cosmologies

Marco Baldi

摘要:

支持暗能量成分主导宇宙并推动其目前加速膨胀的证据在过去十年的宇宙学观测中逐渐增加。如果这种暗能量是由动态标量场给出的,它也可能与宇宙中的其他物质场直接相互作用,特别是与冷的暗物质。这种相互作用会在宇宙学背景演化和宇宙结构的生长上留下新的特征,比如大质量粒子之间的额外长程第五力,或者暗物质粒子质量随时间的变化。我们在这里回顾了这些新的物理效应在N体代码GADGET-2中的实现,并且我们讨论了一系列高分辨率N体模拟的结果,用于选定的相互作用暗能量模型家族,如Baldi等人所述。[20]。有趣的是,我们发现,与以前的索赔相比,暗物质晕的内部过密度在这些模型中相对于LCDM减少,并始终晕浓度显示出逐渐减少增加耦合。此外,耦合诱导的偏置冷暗物质和重子的超密度,决定了其宇宙学值以下的晕重子分数的减少。这些结果在小尺度上缓解了天体物理观测和LCDM模型预测之间的紧张关系,从而为耦合暗能量模型作为宇宙学常数的替代方案开辟了新的空间。

英文摘要:

The evidence in favor of a dark energy component dominating the Universe, and driving its presently accelerated expansion, has progressively grown during the last decade of cosmological observations. If this dark energy is given by a dynamic scalar field, it may also have a direct interaction with other matter fields in the Universe, in particular with cold dark matter. Such interaction would imprint new features on the cosmological background evolution as well as on the growth of cosmic structure, like an additional long-range fifth-force between massive particles, or a variation in time of the dark matter particle mass. We review here the implementation of these new physical effects in the N-body code GADGET-2, and we discuss the outcomes of a series of high-resolution N-body simulations for a selected family of interacting dark energy models, as already presented in Baldi et al. [20]. We interestingly find, in contrast with previous claims, that the inner overdensity of dark matter halos decreases in these models with respect to LCDM, and consistently halo concentrations show a progressive reduction for increasing couplings. Furthermore, the coupling induces a bias in the overdensities of cold dark matter and baryons that determines a decrease of the halo baryon fraction below its cosmological value. These results go in the direction of alleviating tensions between astrophysical observations and the predictions of the LCDM model on small scales, thereby opening new room for coupled dark energy models as an alternative to the cosmological constant.

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。

↑