论文标题
在速度统计上的重子和大量中微子的烙印
Imprint of baryons and massive neutrinos on velocity statistics
论文作者
论文摘要
我们使用Illustris-Tng，Eagle，Cosmo-Owls和Bahamas套件探讨了Baryonic效应（即恒星和AGN反馈）对成对速度矩的影响。气体成分的平均成对速度遵循暗物质的假设在这里进行了小分离，并且我们发现即使在10-20 $ H^{ - 1} \ Mathrm {MPC} $的成对分离时，也有4-5％的速度偏见。在较小的分离下，强度变化，具体取决于亚网格处方。通过隔离不同的物理过程，我们的发现表明，大规模速度偏差主要由恒星而不是AGN反馈驱动。如果不明显，这种速度偏移可能可能会从动力学Sunyaev-Zel'Dovich效应中偏见宇宙学的限制。此外，我们研究了对物质和气体成分的Baryonic和Neutrinonicy自由流效应的成对速度的第一和第二刻。在这两个时刻，我们都能够从大规模中微子的效果中解脱出Baryonic过程的影响。以及以下为20 $ h^{ - 1} \ mathrm {mpc} $的对分离，我们发现成对速度的这些力矩随着中微子质量的增加而降低。因此，我们的工作铺平了一种方法，可以利用成对速度统计来限制未来CMB调查和特殊速度调查的中微子的总和。
We explore the impact of baryonic effects (namely stellar and AGN feedback) on the moments of pairwise velocity using the Illustris-TNG, EAGLE, cosmo-OWLS, and BAHAMAS suites of cosmological hydrodynamical simulations. The assumption that the mean pairwise velocity of the gas component follows that of the dark matter is studied here at small separations, and we find that even at pair separations of 10-20 $h^{-1}\mathrm{Mpc}$ there is a 4-5% velocity bias. At smaller separations, it gets larger with strength varying depending on the subgrid prescription. By isolating different physical processes, our findings suggest that the large scale velocity bias is mainly driven by stellar rather than AGN feedback. If unaccounted for, this velocity offset could possibly bias cosmological constraints from the kinetic Sunyaev-Zel'dovich effect in future cosmic microwave background (CMB) surveys. Furthermore, we examine how the first and the second moment of the pairwise velocity are affected by both the baryonic and the neutrino free-streaming effects for both the matter and gas components. For both moments, we were able to disentangle the effects of baryonic processes from those of massive neutrinos; and below pair separations of 20 $h^{-1}\mathrm{Mpc}$, we find that these moments of the pairwise velocity decrease with increasing neutrino mass. Our work thus paves a way in which the pairwise velocity statistics can be utilised to constrain the summed mass of neutrinos from future CMB surveys and peculiar velocity surveys.
