AI 中文总结
该研究提出新方法，利用星系群相位信息重建0<z<0.6的暗物质MTV场，减少系统不确定性，经测试可准确重建速度场，为DESI BGS数据应用提供可靠途径。
AI 中文摘要
我们提出了一种新方法，利用星系群的相位信息重建红移范围0 < z < 0.6内的宇宙质量、潮汐和速度（MTV）场。该方法用模拟校准的统计映射替代了将星系群与基础暗物质密度场关联时通常需要的显式理论偏差校正，减少了系统不确定性的一个主要来源，使该方法可直接应用于如DESI亮星系巡天（BGS）这类光谱红移巡天项目。我们通过包含全面观测选择效应的模拟红移巡天评估了MTV重建流程的性能。作为示踪物的星系群是通过应用于DESI模拟星系目录的扩展基于晕的群 finder 识别得到的，该目录的视星等极限为m_z < 19.65，产生的星系数量与DESI BGS暗样本（m_r < 20.175）相当。测试显示，重建的速度准确且无偏差，在各个红移区间的剩余弥散约为120 km·s⁻¹。恢复的速度场可让我们将星系群移至其真实空间位置，从而校正Kaiser效应。通过对星系群迭代应用此Kaiser校正，我们进一步重建了潮汐场和质量密度分布。该重建对网格分辨率具有稳定性。总体而言，我们的结果表明，这种基于群的相空间重建为恢复暗物质MTV场提供了可靠途径，在DESI BGS数据的应用上具有良好前景。
英文摘要
We introduce a novel method for reconstructing the cosmic mass, tidal, and velocity (MTV) fields over the redshift range $0 < z < 0.6$ using the phase information of galaxy groups. This approach replaces the explicit theoretical bias correction typically needed to relate galaxy groups to the underlying dark matter density field with a simulation-calibrated statistical mapping, reducing a major source of systematic uncertainty and making the method directly applicable to spectroscopic redshift surveys such as the DESI Bright Galaxy Survey (BGS). We evaluate the performance of our MTV reconstruction pipeline with mock redshift surveys that include a comprehensive set of observational selection effects. The galaxy groups used as tracers are identified with an extended halo-based group finder applied to the DESI mock galaxy catalogue with an apparent magnitude limit of $m_z < 19.65$, yielding a galaxy number comparable to that of the DESI BGS faint sample ($m_r < 20.175$). Our tests show that the reconstructed velocities are accurate and unbiased, with a residual dispersion of $\sim 120\ \mathrm{km\,s^{-1}}$ across the redshift bins. The recovered velocity field allows us to shift galaxy groups to their real-space positions, thereby correcting for the Kaiser effect. By iteratively applying this Kaiser correction to the galaxy groups, we further reconstruct the tidal field and the mass-density distribution. The reconstruction is stable with respect to the grid resolution. Overall, our results demonstrate that this group-based phase-space reconstruction provides a robust pathway to recovering the dark matter MTV fields, with strong prospects for application to DESI BGS data.
Comments24 pages, 19 figures, Submitted to ApJ
