An algorithm to resolve γ-rays from charged cosmic rays with DAMPE  

作　　者：Zun-Lei Xu Kai-Kai Duan Zhao-Qiang Shen Shi-Jun Lei Tie-Kuang Dong Fabio Gargano Simone Garrappa Dong-Ya Guo Wei Jiang Xiang Li Yun-Feng Liang Mario Nicola Mazziotta Maria Fernanda Munoz Salinas Meng Su Valerio Vagelli Qiang Yuan Chuan Yue Jing-Jing Zang Ya-Peng Zhang Yun-Long Zhang Stephan Zimmer 

机构地区：[1]Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China [2]University of Chinese Academy of Sciences, Beijing 100049, China [3]Istituto Nazionale di Fisica Nucleare Sezione di Bari, I-70125, Bari, Italy [4]Istituto Nazionale di Fisica Nucleare Sezione di Perugia, I-06123 Perugia, Italy [5]Dipartimento di Fisica e Geologia, Universita degli Studi di Perugia, I-06123 Perugia, Italy [6]Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China [7]Department of Nuclear and Particle Physics, University of Geneva, CH- 1211, Switzerland [8]School of Astronomy and Space Science, University of Science and Technology of China, Hefei 230026, China [9]Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China [10]State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei 230026, China

出　　处：《Research in Astronomy and Astrophysics》2018年第3期25-36,共12页天文和天体物理学研究（英文版）

基　　金：founded by the strategic priority science and technology projects in space science of the Chinese Academy of Sciences (Nos.XDA04040000 and XDA04040400);supported in part by the National Key Research and Development Program of China (2016YFA0400200);the National Basic Research Program of China (No.2013CB837000);the Strategic Priority Research Program of the Chinese Academy of Sciences “Multi-Waveband Gravitational Wave Universe” (No.XDB23040000);Youth Innovation Promotion Association of CAS;the National Natural Science Foundation of China (Nos.11525313,11673075,11773086,11303107,11303105,11773085,U1738123,U1738136,U1738207 and U1738210);the Young Elite Scientists Sponsorship program by CAST (No.YESS20160196);the 100 Talents Program of Chinese Academy of Sciences;support by the Swiss National Science Foundation (SNSF);Switzerland and the National Institute for Nuclear Physics (INFN),Italy

摘　　要：The DArk Matter Particle Explorer（DAMPE）,also known as Wukong in China,which was launched on 2015 December 17,is a new high energy cosmic ray and γ-ray satellite-borne observatory.One of the main scientific goals of DAMPE is to observe Ge V-Te V high energy γ-rays with accurate energy,angular and time resolution,to indirectly search for dark matter particles and for the study of high energy astrophysics. Due to the comparatively higher fluxes of charged cosmic rays with respect to γ-rays,it is challenging to identify γ-rays with sufficiently high efficiency,minimizing the amount of charged cosmic ray contamination. In this work we present a method to identify γ-rays in DAMPE data based on Monte Carlo simulations,using the powerful electromagnetic/hadronic shower discrimination provided by the calorimeter and the veto detection of charged particles provided by the plastic scintillation detector. Monte Carlo simulations show that after this selection the number of electrons and protons that contaminate the selected γ-ray events at～10 Ge V amounts to less than 1% of the selected sample.Finally,we use flight data to verify the effectiveness of the method by highlighting known γ-ray sources in the sky and by reconstructing preliminary light curves of the Geminga pulsar.The DArk Matter Particle Explorer（DAMPE）,also known as Wukong in China,which was launched on 2015 December 17,is a new high energy cosmic ray and γ-ray satellite-borne observatory.One of the main scientific goals of DAMPE is to observe Ge V-Te V high energy γ-rays with accurate energy,angular and time resolution,to indirectly search for dark matter particles and for the study of high energy astrophysics. Due to the comparatively higher fluxes of charged cosmic rays with respect to γ-rays,it is challenging to identify γ-rays with sufficiently high efficiency,minimizing the amount of charged cosmic ray contamination. In this work we present a method to identify γ-rays in DAMPE data based on Monte Carlo simulations,using the powerful electromagnetic/hadronic shower discrimination provided by the calorimeter and the veto detection of charged particles provided by the plastic scintillation detector. Monte Carlo simulations show that after this selection the number of electrons and protons that contaminate the selected γ-ray events at～10 Ge V amounts to less than 1% of the selected sample.Finally,we use flight data to verify the effectiveness of the method by highlighting known γ-ray sources in the sky and by reconstructing preliminary light curves of the Geminga pulsar.

关 键 词：gamma rays general - instrumentation detectors - methods data analysis 

分 类 号：P172.3[天文地球—天文学]