大样本恒星演化研究组知识库

由欧洲南方天文台发起的麦哲伦星云巡天是一个针对麦哲伦星云的巡天项目,其近红外波段的观测图像覆盖了麦哲伦星云的大部分区域.由于此数据处理系统基于通常目标设计,对于较暗目标的处理结果并不够好.针对这个问题,采取了一系列适用于麦哲伦巡天暗端数据的手动处理方法,通过合并多个时期的巡天数据并采用点扩散函数(Point Spread Function,PSF)测光来提高此巡天数据在暗端的表现.结果在暗端的表现与数据处理系统相差较大,主要体现为精度更高,在误差小于0.1 mag的情况下,其结果较数据处理系统的深0.8 mag,同时发现了更多的有效点源,以50%完备度为限,点源数目高于数据处理系统至少30%.

The Visible and Infrared Survey Telescope for Astronomy (VISTA), which was launched by the European Southern Observatory, has provided data for several parts of survey region in Magellanic Clouds. The multi-epoch survey covers the same region in order to obtain deeper images which will show the information about the fainter objects. The catalogue is provided by VISTA Data Flow System (VDFS) which is designed for the general objects rather than the fainter sources. In order to solve this problem, the deep images from the mate data are made by using SWARP tool, and the photometry of the point spread function is performed on these deep images. Finally, the uncertainties and completeness of deep images are provided, and are compared with the data from VDFS. The result shows more fainter sources can be found by manual processing from their deep images. The final catalogue is 0.8 mag deeper than the VDFS for the sources with error less than 0.1 mag, and the number of sources is increased by 30% at 50% completeness limit.