用DESI DR1目录测量本动速度和层析红偶极子
Measuring peculiar velocity and tomographic redshift dipole with DESI DR1 catalogs
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中文总结 AI 辅助
该研究利用DESI DR1的红移偶极子方法高精度测定运动学偶极子，发现高红移类星体样本的本动速度与CMB结果吻合，红移偶极子可作为更可靠的运动学静止框架探测手段，助力解决宇宙偶极张力问题。
中文摘要 AI 辅助
所谓的“宇宙偶极张力”对宇宙学原理提出了挑战，其假设是从宇宙微波背景（CMB）偶极子推断出的太阳系本动速度，与从大尺度结构数计数偶极子推导出来的本动速度之间存在差异。在此，我们利用暗能量光谱仪（DESI）首次数据发布（DR1）中的红移偶极子方法，对运动学偶极子进行高精度测定。通过利用多普勒效应导致的观测红移调制，该估计量对可能导致传统数计数测量出现偏差的成像系统误差和选择函数不确定性的敏感性本质上更低。我们对四个示踪剂群体进行了层析分析：明亮星系样本、发光红星系、发射线星系和类星体，覆盖范围为0.1<z<2.1。利用1000个EZmock实现来量化巡天几何和统计不确定性。我们发现高红移类星体样本暗示的本动速度为v = 357.95_{-48.47}^{+55.05} km s^{-1}，与CMB推断的369.82 ± 0.11 km s^{-1}值非常吻合。相比之下，互补的数计数分析产生了显著增强的偶极振幅，我们将其归因于大尺度功率的泄漏以及DESI DR1覆盖范围内的不完整性。这些结果表明，红移偶极子为运动学静止框架提供了更清洁、更可靠的探测手段，为高红移下的标准运动学解释提供了有力支持，并有助于解决明显的偶极异常问题。
英文摘要
The so-called ``cosmic dipole tension'' challenges the Cosmological Principle by positing a discrepancy between the Solar System's peculiar velocity inferred from the Cosmic Microwave Background (CMB) dipole and that derived from large-scale structure number-count dipoles. Here we provide a high-precision determination of the kinematic dipole using the redshift-dipole method applied to the first data release (DR1) of the Dark Energy Spectroscopic Instrument (DESI). By exploiting the Doppler-induced modulation of observed redshifts, this estimator is intrinsically less sensitive to imaging systematics and selection-function uncertainties that can bias traditional number-count measurements. We conduct a tomographic analysis of four tracer populations, Bright Galaxy Sample, Luminous Red Galaxies, Emission Line Galaxies, and quasars, spanning $0.1<z<2.1$. Survey geometry and statistical uncertainties are quantified using 1,000 \texttt{EZmock} realizations. We find that the high-redshift QSO sample implies a peculiar velocity of $v = 357.95_{-48.47}^{+55.05}\,\mathrm{km\,s^{-1}}$, in excellent agreement with the CMB-inferred value of $369.82 \pm 0.11\,\mathrm{km\,s^{-1}}$. By contrast, a complementary number-count analysis yields a significantly enhanced dipole amplitude, which we attribute to leakage of large-scale power and to incompleteness within the DESI DR1 footprint. These results indicate that the redshift dipole provides a cleaner and more reliable probe of the kinematic rest frame, offering strong support for the standard kinematic interpretation at high redshift and helping to resolve the apparent dipole anomaly.
发表机构
- Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University（北京师范大学前沿天文与天体物理研究所）
- Department of Physics and Astronomy, Beijing Normal University（北京师范大学物理与天文学院）
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