论文标题
在BAO分析中纠正小置换式插入器
Correcting for small-displacement interlopers in BAO analyses
论文作者
论文摘要
由于无狭窄光谱的分辨率低，包括罗马和欧几里得太空望远镜进行的未来调查将容易出现错误识别，从而在大规模结构目录中以错误的红移而导致Interloper Galaxies。这些中最有害的是真实和假红移之间的位移很小，因此闯入者位置与目标星系相关。我们考虑如何纠正此类污染物，重点是[OIII]目录中的$ \ rmhβ$ interlopers，罗马将观察到，这些污染物将被$ΔD= 97 \，h^{ - 1}} \ fible放置。由于这种位移接近BAO量表，因此在位移量表处的跨行靶星系互相关函数的峰可以改变受污染的目录的自动相关时BAO峰的形状，如果无法正确考虑，则导致不正确的宇宙学测量值。我们考虑如何为受污染的相关函数的单极和四极矩构建模型，包括插入器分数的附加自由参数。该模型的关键输入是形成闯入者的星系人群与主要目标样本之间的互相关。重要的是，使用校准数据估算此内容或使用受污染的小规模自动相关函数对其进行建模，这将是很重要的，如果满足银河系的许多要求，这可能是可能的。我们发现，只要互相关函数是准确已知的，这种方法可以成功地测量BAO扩张参数而没有准确性的显着降解。
Due to the low resolution of slitless spectroscopy, future surveys including those made possible by the Roman and Euclid space telescopes will be prone to line mis-identification, leading to interloper galaxies at the wrong redshifts in the large-scale structure catalogues. The most pernicious of these have a small displacement between true and false redshift such that the interloper positions are correlated with the target galaxies. We consider how to correct for such contaminants, focusing on $\rm Hβ$ interlopers in [OIII] catalogues as will be observed by Roman, which are misplaced by $Δd = 97 \,h^{-1}\,{\rm Mpc}$ at redshift $z = 1$. Because this displacement is close to the BAO scale, the peak in the interloper-target galaxy cross-correlation function at the displacement scale can change the shape of the BAO peak in the auto-correlation of the contaminated catalogue, and lead to incorrect cosmological measurements if not accounted for properly. We consider how to build a model for the monopole and quadrupole moments of the contaminated correlation function, including an additional free parameter for the fraction of interlopers. The key input to this model is the cross-correlation between the population of galaxies forming the interlopers and the main target sample. It will be important to either estimate this using calibration data or to use the contaminated small-scale auto-correlation function to model it, which may be possible if a number of requirements about the galaxy populations are met. We find that this method is successful in measuring the BAO dilation parameters without significant degradation in accuracy, provided the cross-correlation function is accurately known.
