A Cross-matching Service for Data Center of Xinjiang Astronomical Observatory

Abstract Cross-matching is a key technique to achieve fusion of multi-band astronomical catalogs. Due to different equipment such as various astronomical telescopes, the existence of measurement errors and proper motions of the celestial bodies, the same celestial object will have different positions in different catalogs, making it difficult to integrate multi-band or full-band astronomical data. In this study, We propose an online cross-matching method based on pseudo-spherical indexing techniques and develop a service combining with high performance computing system (Taurus) to improve cross-matching efficiency, which is designed for the Data Center of Xinjiang Astronomical Observatory (XAO-DC). Specifically, we use Q3C (Quad Tree Cube) to divide the spherical blocks of celestial object and map the 2-D space composed of Right Ascension (RA) and Declination (Dec) to 1-D space and achieve correspondence between real celestial objects and spherical patches. Finally, we verify the performance of the service using GAIA 3 and PPMXL catalogs. Meanwhile, we send the matching results to VO tools-Topcat and Aladin respectively to get visual results. The experimental results show that the service effectively solves the speed bottleneck problem of cross-matching caused by frequent I/O, and significantly improves the retrieval and matching speed of massive astronomical data.