How accurate are the time delay estimates in gravitational lensing?
How accurate are the time delay estimates in gravitational lensing?
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DOI：
10.1051/0004-6361:20054652
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发表时间：
2006-08-01
影响因子：
6.5
通讯作者：
Raychaudhury, S.
中科院分区：
文献类型：
--
作者：
Cuevas-Tello, J. C.;Tino, P.;Raychaudhury, S.
我们提出了一种新的方法来估计在重力透镜系统中的多个图像的光变曲线之间的时间延迟，基于机器学习的背景下的核方法。我们进行各种实验与人工生成的不规则采样的数据集，以研究各种程度的噪声和存在的各种大小的差距的监测数据的影响。我们比较我们的方法与其他各种流行的方法估计的时间延迟的性能，并得出结论，从人工数据的实验，我们的方法是最不容易丢失的数据和不规则的采样，在合理的范围内的高斯噪声。此后，我们使用我们的方法来确定类星体Q 0957 +561的两个图像之间的时间延迟，从4厘米和6厘米的无线电监测数据，并得出结论，如果只使用两个波长共同的历元的观测，时间延迟给出一致的估计，可以合并产生408 +/- 12天。完整的6 cm数据集涵盖了更长的监测期，产生的值大10%，但这可能是由于采样和缺失数据的差异。
We present a novel approach to estimate the time delay between light curves of multiple images in a gravitationally lensed system, based on Kernel methods in the context of machine learning. We perform various experiments with artificially generated irregularly-sampled data sets to study the effect of the various levels of noise and the presence of gaps of various size in the monitoring data. We compare the performance of our method with various other popular methods of estimating the time delay and conclude, from experiments with artificial data, that our method is least vulnerable to missing data and irregular sampling, within reasonable bounds of Gaussian noise. Thereafter, we use our method to determine the time delays between the two images of quasar Q0957+561 from radio monitoring data at 4 cm and 6 cm, and conclude that if only the observations at epochs common to both wavelengths are used, the time delay gives consistent estimates, which can be combined to yield 408 +/- 12 days. The full 6 cm dataset, which covers a longer monitoring period, yields a value which is 10% larger, but this can be attributed to differences in sampling and missing data.