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arXiv · 2402.15275

Simulation Studies for the First Pathfinder of the CATCH Space Mission

Yiming Huang·Juan Zhang·Lian Tao·Zhengwei Li·Donghua Zhao·Qian-Qing Yin·Xiangyang Wen·Jingyu Xiao·Chen Zhang·Shuang-Nan Zhang·Shaolin Xiong·Qingcui Bu·Jirong Cang·Dezhi Cao·Wen Chen·Siran Ding·Min Gao·Yang Gao·Shujin Hou·Liping Jia·Ge Jin·Dalin Li·Jinsong Li·Panping Li·Yajun Li·Xiaojing Liu·Ruican Ma·Xingyu Pan·Liqiang Qi·Jinhui Rao·Xianfei Sun·Qingwen Tang·Ruijing Tang·Yusa Wang·Yibo Xu·Sheng Yang·Yanji Yang·Yong Yang·Xuan Zhang·Yueting Zhang·Heng Zhou·Kang Zhao·Qingchang Zhao·Shujie Zhao·Zijian Zhao
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Abstract

The Chasing All Transients Constellation Hunters (CATCH) space mission is an intelligent constellation consisting of 126 micro-satellites in three types (A, B, and C), designed for X-ray observation with the objective of studying the dynamic universe. Currently, we are actively developing the first Pathfinder (CATCH-1) for the CATCH mission, specifically for type-A satellites. CATCH-1 is equipped with Micro Pore Optics (MPO) and a 4-pixel Silicon Drift Detector (SDD) array. To assess its scientific performance, including the effective area of the optical system, on-orbit background, and telescope sensitivity, we employ the Monte Carlo software Geant4 for simulation in this study. The MPO optics exhibit an effective area of $41$ cm$^2$ at the focal spot for 1 keV X-rays, while the entire telescope system achieves an effective area of $29$ cm$^2$ at 1 keV when taking into account the SDD detector's detection efficiency. The primary contribution to the background is found to be from the Cosmic X-ray Background. Assuming a 625 km orbit with an inclination of $29^\circ$, the total background for CATCH-1 is estimated to be $8.13\times10^{-2}$ counts s$^{-1}$ in the energy range of 0.5--4 keV. Based on the background within the central detector and assuming a Crab-like source spectrum, the estimated ideal sensitivity could achieve $1.9\times10^{-12}$ erg cm$^{-2}$ s$^{-1}$ for an exposure of 10$^4$ s in the energy band of 0.5--4 keV. Furthermore, after simulating the background caused by low-energy charged particles near the geomagnetic equator, we have determined that there is no need to install a magnetic deflector.

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Yiming Huang, Juan Zhang, Lian Tao, Zhengwei Li, Donghua Zhao, Qian-Qing Yin, Xiangyang Wen, Jingyu Xiao, Chen Zhang, Shuang-Nan Zhang, Shaolin Xiong, Qingcui Bu, Jirong Cang, Dezhi Cao, Wen Chen, Siran Ding, Min Gao, Yang Gao, Shujin Hou, Liping Jia, Ge Jin, Dalin Li, Jinsong Li, Panping Li, Yajun Li, Xiaojing Liu, Ruican Ma, Xingyu Pan, Liqiang Qi, Jinhui Rao, Xianfei Sun, Qingwen Tang, Ruijing Tang, Yusa Wang, Yibo Xu, Sheng Yang, Yanji Yang, Yong Yang, Xuan Zhang, Yueting Zhang, Heng Zhou, Kang Zhao, Qingchang Zhao, Shujie Zhao, Zijian Zhao. 2024-02-23. Simulation Studies for the First Pathfinder of the CATCH Space Mission. https://doi.org/10.1007/s10686-024-09924-0

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