文章基本信息

标题：KiDS+VIKING-450: Improved cosmological parameter constraints from redshift calibration with self-organising maps
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作者：Angus H. Wright ; Hendrik Hildebrandt ; Jan Luca van den Busch 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2020
卷号：640
页码：1-10
DOI：10.1051/0004-6361/202038389
语种：English
出版社：EDP Sciences
摘要：We present updated cosmological constraints for the KiDS+VIKING-450 cosmic shear data set (KV450) estimated through redshift distributions and photometric samples defined using self-organising maps (SOMs). Our fiducial analysis finds marginal posterior constraints ofS8≡σ8Ωm/0.3 = 0.716−0.038+0.043, which are smaller but otherwise consistent with previous works that have applied this data set (|ΔS8| = 0.023). We analysed additional samples and redshift distributions set up in three ways: (1) by excluding certain spectroscopic surveys during redshift calibration; (2) by excluding lower-confidence spectroscopic redshifts in redshift calibration; and (3) by considering only those photometric sources which are jointly calibrated by at least three spectroscopic surveys. In all cases, the method utilised here has been proven to be robust: we find a maximal deviation from our fiducial analysis of |ΔS8| ≤ 0.011 for all samples defined and analysed using our SOM. To demonstrate the reduction in systematic biases found within our analysis, we highlight our results when performing redshift calibration without the DEEP2 spectroscopic data set. In this case, we find marginal posterior constraints ofS8= 0.707−0.042+0.046; this is a difference, with respect to the fiducial, that is both significantly smaller and in the opposite direction with regard to the equivalent shift from previous works. These results suggest that our improved cosmological parameter estimates are not sensitive to pathological misrepresentations of photometric sources by the spectroscopy used for direct redshift calibration and, therefore, that this systematic effect cannot be responsible for the observed difference betweenS8estimates made with KV450 andPlanckCMB probes.
关键词：engravitational lensing: weakcosmology: observationssurveys