论文标题
减轻弱透镜剪切估计中底采样的影响
Mitigating the effects of undersampling in weak lensing shear estimation with metacalibration
论文作者
论文摘要
元素校准是一种最新技术，用于测量从采样良好的星系图像中测量弱重力透镜剪切。我们研究了从拟合椭圆形的高斯到不足采样的星系图像的元素测量的剪切精度。在这种情况下，元校准会引入混叠效应，从而导致欧几里得大约0.01的集合乘法剪切偏置，甚至对于罗马空间望远镜，甚至更大，远远超过了任务的要求。我们发现，可以通过从更宽的高斯函数的加权力矩计算形状来减轻这种混叠偏差，从而交易偏见，从而略有增加测量值的差异。我们表明，这种方法对考虑到重点的函数是强大的，并且满足了具有中等至高信噪比的星系的欧几里得的严格要求。因此，我们主张将元校准作为即将到来的空间任务弱镜头的可行剪切测量选项。
Metacalibration is a state-of-the-art technique for measuring weak gravitational lensing shear from well-sampled galaxy images. We investigate the accuracy of shear measured with metacalibration from fitting elliptical Gaussians to undersampled galaxy images. In this case, metacalibration introduces aliasing effects leading to an ensemble multiplicative shear bias about 0.01 for Euclid, and even larger for the Roman Space Telescope, well exceeding the missions' requirements. We find that this aliasing bias can be mitigated by computing shapes from weighted moments with wider Gaussians as weight functions, thereby trading bias for a slight increase in variance of the measurements. We show that this approach is robust to the point-spread function in consideration and meets the stringent requirements of Euclid for galaxies with moderate to high signal-to-noise ratios. We therefore advocate metacalibration as a viable shear measurement option for weak lensing from upcoming space missions.
