本站原创论文中英文摘 要
作者姓名:张
论文题目:γ实验研究Multi-TeV宇宙线各向异性
作者简介:张毅,男,1980年10月出生,2003年9月师从于中国科学院高能物理研究所胡红波研究员,于2016年7月获博士学位.
中文摘 要
γ和ARGO实验都是通过观测宇宙线广延大气簇射产生的次级粒子来获得宇宙线的方向和能量的,这类实验能够宽视野(赤纬-14.89o~75.11o)全天候的观测.其中ASγ阵列在1997年2月到2005年10月长时间稳定的运行,提供了研究宇宙线各向异性现象的最好数据样本.传统谐波分析的方法,只能得到一维各向异性低阶谐波项的振幅和相位.利用等天顶角原理,我们发展了一套分析各向异性的方法,这套方法能够得到高精度的两维各向异性天图.
在太阳时的窗口中,通过对12.5TeV能量段样本的分析,观测到了与预期相符因地球公转产生的Compton-Getting效应.在低能段观测到一个额外的调制,但需要进一步的研究.在恒星时的窗口中,除了更精细地观测到已知的"tail-in"和"loss-cone"结构,还发现在Cygnus区域也有宇宙线流强的超出.在分析恒星时各向异性的能量依赖时,发现随着能量的提高,"tail-in","loss-cone"效应的影响逐渐淡化,但在300TeV能区没有发现因为太阳绕银河系中心旋转产生的Compton-Getting效应,意味着银河系宇宙线绕银河系中心共转.这些结果暗示着这个能区的宇宙线粒子受到太阳系附近环境的银河系磁场束缚.
关 键 词:StudytheAnisotropyofMulti-TeV
CoicRayswithYangbajingASγExperiment
ZhangYi
ABSTRACT
TheintensityofGalacticcoicraysisnearlyisotropicbecauseoftheinfluenceofmagicfieldsintheMilkyWay.GiventhefactthatthemaximumamplitudeoftheanisotropyinTeVenergyrangeisonlyabout0.001,alongtermstableobservationandhighprecisionanalysisareinevitableforthestudiesofsuchasubtleanisotropy.BothASγandARGOexperimentsinYangbajingobservatoryobtainthedirectionalandenergyinformationofthecoicraybymeasurementsofthesecondaryparticlesgeneratedintheairshower.WiththeexcellentoperationoftheAS-gammaarrayfrom1997.2to2005.10,alargedatasamplewasobtained,whichisespeciallysuitablefortheanalysisoflargescalecoicrayanisotropy,owingtoitslargefieldofviewandhighstabilityinperformance.Thetraditionalanisotropyanalysisislimitedtomeasurethefirstfewtermsoftheharmonicalexpansionandiscarriedonlyinonedimensionalspace.Basedontheequi-zenithanglemethod,thisworkhasdevelopedanewanalysiethodwhichallowsthetwo-dimensionalandhighprecisionanisotropymeasurementpossibleforthefirsttime.
Inthesolartimeframe,thetwo-dimensionalanisotropyisobservedat12.5TeVenergyrange,andconsistentwiththeexpectedCompton-GettingeffectduetotheterrestrialorbitalmotionaroundtheSun.Anadditionalmodulationappearstoexistincaseoflowenergybutfurtherstudiesisneeded.Inthesiderealtimeframe,besidesrevealingfinerdetailsoftheknownanisotropiesof"tail-in"and"loss-cone",anewponentisuncoveredaroundtheCygnusregiondirection.Forcoic-rayenergiesuptoafewhundredTeV,allponentsofanisotropieadeaway,theCompton-GettingeffectduetothesolarmotionaroundtheGalacticcenterisnotobservedwhichindicatesthattheGalacticcoicraysco-rotatearoundtheGalacticcenterwiththesolarenvironment.TheseresultsheanimplicationthatcoicraysinTeVenergyrangearestronglytrappedbytheGalacticmagicfieldinthelocalenvironment.
Keywords:Coicray,anisotropy,corotation