分类： 天文学 >> 天文学 提交时间： 2023-02-19
Panping Li
Qian-Qing Yin
Zhengwei Li
Lian Tao
Xiangyang Wen
Shuang-Nan Zhang
Liqiang Qi
Juan Zhang
Donghua Zhao
Dalin Li
Xizheng Yu
Qingcui Bu
Wen Chen
Yupeng Chen
Yiming Huang
Yue Huang
Ge Jin
Gang Li
Hongbang Liu
Xiaojing Liu
摘要： In time-domain astronomy, a substantial number of transients will be discovered by multi-wavelength and multi-messenger observatories, posing a great challenge for follow-up capabilities. We have thus proposed an intelligent X-ray constellation, the Chasing All Transients Constellation Hunters (CATCH) space mission. Consisting of 126 micro-satellites in three types, CATCH will have the capability to perform follow-up observations for a large number of different types of transients simultaneously. Each satellite in the constellation will carry lightweight X-ray optics and use a deployable mast to increase the focal length. The combination of different optics and detector systems enables different types of satellites to have multiform observation capabilities, including timing, spectroscopy, imaging, and polarization. Controlled by the intelligent system, different satellites can cooperate to perform uninterrupted monitoring, all-sky follow-up observations, and scanning observations with a flexible field of view (FOV) and multi-dimensional observations. Therefore, CATCH will be a powerful mission to study the dynamic universe. Here, we present the current design of the spacecraft, optics, detector system, constellation configuration and observing modes, as well as the development plan.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Juan Zhang
Liqiang Qi
Yanji Yang
Juan Wang
Yuan Liu
Weiwei Cui
Donghua Zhao
Shumie Jia
Tianming Li
Tianxiang Chen
Gang Li
Xiaofan Zhao
Yong Chen
Huaqiu Liu
Congying Bao
Ju Guan
Liming Song
Weimin Yuan
摘要： As a space X-ray imaging mission dedicated to time-domain astrophysics, the Einstein Probe (EP) carries two kinds of scientific payloads, the wide-field X-ray telescope (WXT) and the follow-up X-ray telescope (FXT). FXT utilizes Wolter-I type mirrors and the pn-CCD detectors. In this work, we investigate the in-orbit background of FXT based on Geant4 simulation. The impact of various space components present in the EP orbital environment are considered, such as the cosmic photon background, cosmic ray primary and secondary particles (e.g. protons, electrons and positrons), albedo gamma rays, and the low-energy protons near the geomagnetic equator. The obtained instrumental background at 0.5-10 keV, which is mainly induced by cosmic ray protons and cosmic photon background, corresponds to a level of $\sim$3.1$\times$10$^{-2}$ counts s$^{-1}$ keV$^{-1}$ in the imaging area of the focal plane detector (FPD), i.e. 3.7$\times$10$^{-3}$ counts s$^{-1}$ keV$^{-1}$ cm$^{-2}$ after normalization. Compared with the instrumental background, the field of view (FOV) background, which is induced by cosmic photons reflected by the optical mirror, dominates below 2 keV. Based on the simulated background level within the focal spot (a 30$^{\prime\prime}$-radius circle), the sensitivity of FXT is calculated, which could theoretically achieve several $\mu$crab (in the order of 10$^{-14}$ erg cm$^{-2}$ s$^{-1}$) in 0.5-2 keV and several tens of $\mu$crab (in the order of 10$^{-13}$ erg cm$^{-2}$ s$^{-1}$) in 2-10 keV for a pointed observation with an exposure of 25 minutes. This sensitivity becomes worse by a factor of $\sim2$ if additional 10% systematic uncertainty of the background subtraction is included.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Panping Li
Qian-Qing Yin
Zhengwei Li
Lian Tao
Xiangyang Wen
Shuang-Nan Zhang
Liqiang Qi
Juan Zhang
Donghua Zhao
Dalin Li
Xizheng Yu
Qingcui Bu
Wen Chen
Yupeng Chen
Yiming Huang
Yue Huang
Ge Jin
Gang Li
Hongbang Liu
Xiaojing Liu
摘要： In time-domain astronomy, a substantial number of transients will be discovered by multi-wavelength and multi-messenger observatories, posing a great challenge for follow-up capabilities. We have thus proposed an intelligent X-ray constellation, the Chasing All Transients Constellation Hunters (CATCH) space mission. Consisting of 126 micro-satellites in three types, CATCH will have the capability to perform follow-up observations for a large number of different types of transients simultaneously. Each satellite in the constellation will carry lightweight X-ray optics and use a deployable mast to increase the focal length. The combination of different optics and detector systems enables different types of satellites to have multiform observation capabilities, including timing, spectroscopy, imaging, and polarization. Controlled by the intelligent system, different satellites can cooperate to perform uninterrupted monitoring, all-sky follow-up observations, and scanning observations with a flexible field of view (FOV) and multi-dimensional observations. Therefore, CATCH will be a powerful mission to study the dynamic universe. Here, we present the current design of the spacecraft, optics, detector system, constellation configuration and observing modes, as well as the development plan.
点击量
待评议
点击量
下载量
评论
