论文标题
阐明SDS中的星系组件偏置
Elucidating Galaxy Assembly Bias in SDSS
论文作者
论文摘要
我们使用Elucid（一种最新的约束模拟，可以准确地重建SDSS体积中的初始密度扰动，研究了Sloan数字天空调查（SDSS）主星系样品中的星系组件偏置水平。除了Elucid Haloes之外，我们开发了一个扩展的HOD模型，其中包括中央和卫星星系的组装偏置，被参数化为$ \ Mathcal {Q} _ \ Mathrm {Cen} $和$ \ Mathcal {Q} _ \ Mathrm {satrm {sat} $，以分别预测一个sue，特别是，我们的信托约束采用了以$ 8 \，\ Mathrm {mpc} \，h^{ - 1} $ scales $ n_8^g $以及预计的跨五Q $ n_8^g $ Quintiles Quintiles Quintiles of $ N_8^G $与我们的整个Galaxy选择的五Q Q Q $ NESPALAXY的星系的交叉相交功能的概率分布。我们通过使用受约束和无约束的模拟将相同的可观察结果拟合以模拟数据来对我们方法的疗效进行广泛的测试。我们发现，在许多情况下，两个模拟之间的宇宙方差水平会产生偏见的约束，如果使用了无约束的模拟，则会导致错误检测星系组装偏置。当将我们的方法应用于SDSS数据时，Elucid重建有效地消除了SDSS中宇宙差异和星系组装偏置之间的强劲变性，从而使我们能够对后者产生准确而严格的约束。我们的基金会质子约束，对于高于恒星质量阈值的星系$ m _*{=} 10^{10.2} \，h^{ - 2} \，m_ \ odot $，is $ \ mathcal {q} $ \ mathcal {q} _ \ mathrm {sat} {=} 0.09 \ pm {0.10} $，表明没有证据表明SDSS探索的本地宇宙中有明显的〜（$>2σ$）星系组件偏置。最后，我们的方法为在DESI和PFS等未来调查中对Galaxy-Halo连接的稳健建模提供了有希望的途径。
We investigate the level of galaxy assembly bias in the Sloan Digital Sky Survey (SDSS) main galaxy sample using ELUCID, a state-of-the-art constrained simulation that accurately reconstructed the initial density perturbations within the SDSS volume. On top of the ELUCID haloes, we develop an extended HOD model that includes the assembly bias of central and satellite galaxies, parameterized as $\mathcal{Q}_\mathrm{cen}$ and $\mathcal{Q}_\mathrm{sat}$, respectively, to predict a suite of one- and two-point observables. In particular, our fiducial constraint employs the probability distribution of the galaxy number counts measured on $8\,\mathrm{Mpc}\,h^{-1}$ scales $N_8^g$ and the projected cross-correlation functions of quintiles of galaxies selected by $N_8^g$ with our entire galaxy sample. We perform extensive tests of the efficacy of our method by fitting the same observables to mock data using both constrained and non-constrained simulations. We discover that in many cases the level of cosmic variance between the two simulations can produce biased constraints that lead to an erroneous detection of galaxy assembly bias if the non-constrained simulation is used. When applying our method to the SDSS data, the ELUCID reconstruction effectively removes an otherwise strong degeneracy between cosmic variance and galaxy assembly bias in SDSS, enabling us to derive an accurate and stringent constraint on the latter. Our fiducial ELUCID constraint, for galaxies above a stellar mass threshold $M_*{=}10^{10.2}\,h^{-2}\,M_\odot$, is $\mathcal{Q}_\mathrm{cen}{=}{-}0.09\pm{0.05}$ and $\mathcal{Q}_\mathrm{sat}{=}0.09\pm{0.10}$, indicating no evidence for a significant~($>2σ$) galaxy assembly bias in the local Universe probed by SDSS. Finally, our method provides a promising path to the robust modelling of the galaxy-halo connection within future surveys like DESI and PFS.
