论文标题
共同图像的PSF
PSFs of coadded images
论文作者
论文摘要
我们提供了详细的探索，探索了所得共辅助图像的共同辅助方案的选择与点传播函数（PSF）之间的联系。特别是，我们研究了共同算法的哪些属性导致最终的共辅入图像具有明确定义的PSF。讨论的关键要素如下： 1。我们提供了一个说明，即线性共辅助方案如何产生一个COADD，即使对于相对简单的场景和重量功能的选择，也缺乏定义明确的PSF。 2。我们提供了一个更正式的证明，即线性COADD仅具有明确定义的PSF，如果（a）每个输入图像具有相同的PSF，或者（b）COADD由与信号无关的权重产生。 3。我们讨论了一些原因，即两种合理的非线性共辅助算法（中位数和剪裁均值）未能为恒星产生一致的PSF曲线。 4。我们证明了所有非线性共同辅助过程都无法为扩展对象产生明确的PSF。 最后，我们得出的结论是，在需要明确定义的PSF的任何目的中，都应使用与信号无关的权重的线性共辅助方案，并且在典型的感兴趣对象之间近似均匀。
We provide a detailed exploration of the connection between choice of coaddition schemes and the point-spread function (PSF) of the resulting coadded images. In particular, we investigate what properties of the coaddition algorithm lead to the final coadded image having a well-defined PSF. The key elements of this discussion are as follows: 1. We provide an illustration of how linear coaddition schemes can produce a coadd that lacks a well-defined PSF even for relatively simple scenarios and choices of weight functions. 2. We provide a more formal demonstration of the fact that a linear coadd only has a well-defined PSF in the case that either (a) each input image has the same PSF or (b) the coadd is produced with weights that are independent of the signal. 3. We discuss some reasons that two plausible nonlinear coaddition algorithms (median and clipped-mean) fail to produce a consistent PSF profile for stars. 4. We demonstrate that all nonlinear coaddition procedures fail to produce a well-defined PSF for extended objects. In the end, we conclude that, for any purpose where a well-defined PSF is desired, one should use a linear coaddition scheme with weights that do not correlate with the signal and are approximately uniform across typical objects of interest.
