线发射星系数计数和谱线强度图中运动学诱导的偶极各向异性
Kinematically induced dipole anisotropy in line-emitting galaxy number counts and line intensity maps
AI总结：
本研究揭示谱线强度图中存在运动学诱导的偶极各向异性，提出多频偶极测量可精确测定太阳系速度并约束天体物理参数，评估了SPHEREx等巡天的测量潜力，还探讨了其对局域宇宙非标准宇宙学研究的意义。
摘要：
太阳系相对于各向同性辐射背景（如宇宙微波背景）的运动，会因多普勒效应在背景中诱导出偶极各向异性。针对星系连续辐射的流量受限观测也已得到广泛研究，证实多普勒效应和光行差效应会引发偶极各向异性。我们的研究表明，类似的偶极各向异性存在于谱线强度图中，既可以星系数计数的形式呈现，也能以弥漫强度图的形式表征。这些偶极各向异性的振幅不仅取决于太阳系相对于大尺度结构的运动速度，还与单极子（全天平均）成分的时间演化有关。由于不同红移产生的多频率信号具有相互独立的起源，测量多个频率处的偶极可借助冗余信息极为精确地测定太阳系运动速度。我们发现这类测量甚至能够约束近邻宇宙中的天体物理参数。我们探究了现有及即将开展的巡天项目开展偶极测量的潜力，得出结论：通过SPHEREx（宇宙光谱光度计、光度计和星系外探测器）开展的星系谱线数计数测量，将是首次实现谱线星系分布偶极各向异性测量的最优方案。精度合理的LIM（谱线强度映射）巡天也被认为颇具前景。我们还讨论了这些实验是否可能揭示我们局域宇宙的特殊性质——近期的重子声学振荡特征测量和Alcock-Paczynski检验结果表明，这似乎需要一种不同于简单LambdaCDM模型的非标准宇宙学来解释。
英文摘要：
The motion of the solar system against an isotropic radiation background, such as the cosmic microwave background, induces a dipole anisotropy in the background due to the Doppler effect. Flux-limited observation of the continuum radiation from galaxies also has been studied extensively to show a dipole anisotropy due to the Doppler effect and the aberration effect. We show that a similar dipole anisotropy exists in spectral-line intensity maps, represented as either galaxy number counts or the diffuse intensity maps. The amplitude of these dipole anisotropies is determined by not only the solar velocity against the large-scale structures but also the temporal evolution of the monopole (sky-average) component. Measuring the dipole at multiple frequencies, which have mutually independent origins due to their occurrence from multiple redshifts, can provide a very accurate measure of the solar velocity thanks to the redundant information. We find that such a measurement can even constrain astrophysical parameters in the nearby universe. We explore the potential for dipole measurement of existing and upcoming surveys, and conclude that the spectral number count of galaxies through SPHEREx will be optimal for the first measurement of the dipole anisotropy in the spectral-line galaxy distribution. LIM surveys with reasonable accuracy are also found to be promising. We also discuss whether these experiments might reveal a peculiar nature of our local universe, that seems to call for a non-standard cosmology other than the simple LambdaCDM model as suggested by recent measures of the baryon acoustic oscillation signatures and the Alcock-Paczynski tests.
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