Forecasting the potential of weak lensing magnification to enhance LSST large-scale structure analyses
Forecasting the potential of weak lensing magnification to enhance LSST large-scale structure analyses
复制标题
预测弱透镜放大率增强 LSST 大规模结构分析的潜力
DOI：
10.1093/mnras/stac872
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发表时间：
2022
影响因子：
4.8
通讯作者：
Mahony C
中科院分区：
文献类型：
--
作者：
Mahony C
最近的研究表明，弱透镜放大倍数必须包含在即将进行的大规模结构分析中，例如维拉·C·鲁宾天文台遗产时空巡天（LSST），以避免宇宙学结果出现偏差。在这项工作中，我们研究了放大倍率是否对宇宙学约束的精度产生积极影响，以及是否有必要避免偏差。我们使用 LSST 模拟目录和晕模型来计算星系功率谱来预测这一点。我们发现，包括放大倍数对 LSST 星系聚类分析的宇宙学参数约束的精度几乎没有影响，其中晕模型参数还受到星系光度函数的约束。特别是，我们发现对于 LSST 金样本（i< 25.3），包括弱透镜放大倍率仅将 Ωm 上的星系聚类约束提高了 1.03 倍，而当使用非常深的 LSST 模拟样本（i< 26.5）时，则提高了 1.3 倍。由于放大率主要有助于聚类测量并提供与宇宙剪切类似的信息，因此对于组合的星系聚类和剪切分析，这种改进将会减少。我们还确认，不模拟弱透镜放大率将会灾难性地使 LSST 的宇宙学结果产生偏差。因此，LSST 大规模结构分析中必须包含放大倍数，即使它不会显着提高宇宙学约束的精度。
Recent works have shown that weak lensing magnification must be included in upcoming large-scale structure analyses, such as for the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), to avoid biasing the cosmological results. In this work, we investigate whether including magnification has a positive impact on the precision of the cosmological constraints, as well as being necessary to avoid bias. We forecast this using an LSST mock catalogue and a halo model to calculate the galaxy power spectra. We find that including magnification has little effect on the precision of the cosmological parameter constraints for an LSST galaxy clustering analysis, where the halo model parameters are additionally constrained by the galaxy luminosity function. In particular, we find that for the LSST gold sample (i< 25.3) including weak lensing magnification only improves the galaxy clustering constraint on Ωmby a factor of 1.03, and when using a very deep LSST mock sample (i< 26.5) by a factor of 1.3. Since magnification predominantly contributes to the clustering measurement and provides similar information to that of cosmic shear, this improvement would be reduced for a combined galaxy clustering and shear analysis. We also confirm that not modelling weak lensing magnification will catastrophically bias the cosmological results from LSST. Magnification must therefore be included in LSST large-scale structure analyses even though it does not significantly enhance the precision of the cosmological constraints.