GECAM定位方法及模拟分析  

The localization method of GECAM and simulation analysis

作　　者：廖进元 罗琦 朱玥[1] 宋欣颖 彭文溪[1] 肖硕 李刚[1] 熊少林[1] LIAO Jin-Yuan;LUO Qi;ZHU Yue;SONG Xin-Ying;PENG Wen-Xi;XIAO Shuo;LI Gang;XIONG Shao-Lin(Key Laboratory of Particle Astrophysics,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院高能物理研究所粒子天体物理重点实验室,北京100049 [2]中国科学院大学,北京100049

出　　处：《中国科学：物理学、力学、天文学》2020年第12期106-115,共10页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：中国科学院战略性先导科技专项(编号:XDA15052700)和中国科学院前沿科学重点研究计划项目(编号:QYZDB-SSW-SLH012)资助。

摘　　要：引力波暴高能电磁对应体全天监测器(Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor,GECAM)卫星计划于2020年底发射,将实现对引力波高能电磁对应体等高能暴发现象的全天监测.GECAM对伽马射线暴的定位是其最重要的科学需求之一.我们建立了同时拟合伽马射线暴的能谱和定位的GECAM地面定位方法,并结合GECAM当前质量模型的仪器响应和本底模拟,对此定位方法的GECAM定位能力进行了考察,得到了不同亮度、不同能谱硬度、不同暴发持续时间等参数的伽马射线暴的定位精度.对于典型亮度(10–1000 keV能段下,通量为10^-6 erg s^-1 cm^-2,持续10 s)的中等硬度谱的定位精度在0.6°(1-σ统计误差)左右.我们还考察了两个特殊暴发事件:(1)对于快速射电暴FRB 131104的疑似高能辐射对应体,GECAM定位误差为5°左右;(2)对于引力波事件GW170817的电磁对应体(GRB 170817A),GECAM定位误差为10°左右.Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM) is scheduled to launch in late2020. It will monitor the whole sky for gamma-ray transients, such as Gamma-Ray Bursts(GRBs) and high-energy electromagnetic counterpart of gravitational wave events. One of the key scientific capabilities of GECAM is to localize the GRB. In this study, we established a ground localization method for GECAM by simultaneously fitting the spectrum and location of GRB. In addition, with the instrument response and in-flight background simulated using the current GECAM mass model, we examined the localization capability of GECAM. As a result, we derived the relationship between localization accuracy and different parameters of the GRB, such as brightness, spectral hardness, and burst duration. Moreover,for typical brightness(flux 10^-6 erg s^-1 cm^-2 in 10–1000 ke V energy range with duration of 10 s) spectrum of medium hardness, the localization accuracy was observed at about 0.6°(1-σ statistical error). We also performed localization for two special bursts:(1) the suspected high-energy counterpart of the Fast Radio Burst(FRB 131104) with the GECAM localization error approximately 5°and(2) the gamma-ray electromagnetic counterpart(GRB 170817 A) of the first binary neutron star merger gravitational wave event GW170817, with GECAM localization error of about 10°.

关 键 词：GECAM 定位算法 模拟 

分 类 号：P111[天文地球—天文学] P142.84