Mapping the same volume of space with different tracers allows us to obtain information through estimated quantities exploiting the multi-tracer technique. Indeed, the cross-correlation of different probes provides information that cannot be otherwise obtained. In addition, some estimated quantities are not sensitive to the noise produced by the sampling variance but are only limited by the shot (or Poisson) noise, an attractive perspective. A simple example is the ratio between the (cross)-correlations, measuring the ratio of the bias parameters. Multi-tracer approaches can thereby provide additional information that cannot be extracted from independent volumes.

中文翻译：

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交叉相关在多示踪剂领域的作用

用不同的示踪剂映射相同体积的空间使我们能够通过利用多示踪剂技术的估计数量来获取信息。事实上，不同探针的互相关提供了其他方式无法获得的信息。此外，一些估计量对采样方差产生的噪声不敏感，而仅受散粒（或泊松）噪声的限制，这是一个有吸引力的观点。一个简单的例子是（交叉）相关之间的比率，测量偏差参数的比率。多示踪剂方法因此可以提供无法从独立卷中提取的附加信息。