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arXiv 1901.03096astro-ph.CO
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tSZ星系团宇宙学中的质量偏差演化

Mass bias evolution in tSZ cluster cosmology

Laura Salvati, Marian Douspis, Anna Ritz, Nabila Aghanim, Arif Babul

摘要:

通过热Sunyaev-Zeldovich(tSZ)效应观测到的星系团是最近的宇宙学探测。宇宙学约束的精确度主要受到当前星系团物理学知识的影响,这些知识通过标度关系进入分析。在这里,我们的目标是研究系统的不确定性,质量偏差,$b$的最重要的来源之一。我们分析了质量红移依赖的影响,采用幂律参数化。我们将此参数化的tSZ数计数和功率谱的组合,发现一个暗示的红移依赖,导致更高的红移的质量偏差值下降。我们测试了我们的结果的鲁棒性不同的质量偏差校准和离散红移的依赖。我们发现我们的结果是依赖于集群的样本,我们正在考虑,特别是获得一个逆(减少)红移的依赖时,忽略$z<0.2$集群。我们分析了这种参数化对组合的宇宙微波背景(CMB)的主要各向异性和tSZ星系团的影响。我们发现一个较好的恒定值的质量偏差,有$(1-b) =0.62 \pm 0.05$。相对于弱透镜效应和数值模拟估计,$b$的相应值太高。因此,我们的结论是,这种质量红移参数化无助于解决其余的CMB和tSZ集群观测之间的差异。

英文摘要:

Galaxy clusters observed through the thermal Sunyaev-Zeldovich (tSZ) effect are a recent cosmological probe. The precision on the cosmological constraints is affected mainly by the current knowledge of cluster physics, which enters the analysis through the scaling relations. Here we aim to study one of the most important sources of systematic uncertainties, the mass bias, $b$. We have analysed the effects of a mass-redshift dependence, adopting a power-law parametrisation. We applied this parametrisation to the combination of tSZ number counts and power spectrum, finding a hint of redshift dependence that leads to a decreasing value of the mass bias for higher redshift. We tested the robustness of our results for different mass bias calibrations and a discrete redshift dependence. We find our results to be dependent on the clusters sample that we are considering, in particular obtaining an inverse (decreasing) redshift dependence when neglecting $z<0.2$ clusters. We analysed the effects of this parametrisation on the combination of cosmic microwave background (CMB) primary anisotropies and tSZ galaxy clusters. We find a preferred constant value of mass bias, having $(1-b) =0.62 \pm 0.05$. The corresponding value of $b$ is too high with respect to weak lensing and numerical simulations estimations. Therefore we conclude that this mass-redshift parametrisation does not help in solving the remaining discrepancy between CMB and tSZ clusters observations.

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