Probing cosmic rays in nearby giant molecular clouds with the Fermi Large Area Telescope

CORC > 紫金山天文台 > 中国科学院紫金山天文台 > 暗物质和空间天文实验室

	Probing cosmic rays in nearby giant molecular clouds with the Fermi Large Area Telescope
	Yang, Rui-zhi 1,2; de Ona Wilhelmi, Emma 1,5; Aharonian, Felix 1,3,4
刊名	ASTRONOMY & ASTROPHYSICS
	2014-06-01
卷号	566 期号:0 页码:0
关键词	cosmic rays gamma rays: ISM ISM: clouds
ISSN号	0004-6361
英文摘要	We report the results of our study of the energy spectra and absolute fluxes of cosmic rays (CRs) in the Local Galaxy based on a five-year gamma-ray observation with the Fermi Large Area Telescope (LAT) of eight nearby giant molecular clouds (GMCs) belonging to the Gould Belt. The gamma-ray signals obtained with high statistical significance allow the determination of gamma-ray spectra above 300 MeV with adequate precision for extraction of the energy distributions of CRs in these clouds. Remarkably, both the derived spectral indices and the absolute fluxes of CR protons in the energy interval 10-100 GeV agree with the recent direct measurements of local CRs by the PAMELA experiment. This is strong evidence of a quite homogeneous distribution of CRs, at least within several hundred parsecs of the Local Galaxy. Combined with the well established energy-dependent time of escape of CRs from the Galaxy, tau(E) proportional to E-delta with delta approximate to 0.5-0.6, the measured spectrum implies a CR spectral index of the (acceleration) source of approximate to E-2.3. At low energies, the spectra of gamma rays appear to vary from one cloud to another. This implies spatial variations of the energy spectra of CRs below 10 GeV, which at such low energies could be explained naturally by both the impact of the propagation effects and the contribution of CR locally accelerated inside the clouds.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	GAMMA-RAYS ; MILKY-WAY ; CO SURVEY ; PROPAGATION ; SPECTRUM ; REMNANTS ; PROTON ; PAMELA ; GAS
收录类别	SCI
语种	英语
WOS记录号	WOS:000338681500004
公开日期	2014-11-20
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/10557]
专题	紫金山天文台_暗物质和空间天文实验室
作者单位	1.Max Planck Inst Kernphys, D-69029 Heidelberg, Germany 2.Chinese Acad Sci, Key Lab Dark Matter & Space Astron, Purple Mt Observ, Nanjing 210008, Jiangsu, Peoples R China 3.Dublin Inst Adv Studies, Dublin 2, Ireland 4.Gran Sasso Sci Inst, I-67100 Laquila, AQ, Italy 5.CSIC, Inst Cincies Espai, IEEC, Bellaterra 08193, Spain
推荐引用方式 GB/T 7714	Yang, Rui-zhi,de Ona Wilhelmi, Emma,Aharonian, Felix. Probing cosmic rays in nearby giant molecular clouds with the Fermi Large Area Telescope[J]. ASTRONOMY & ASTROPHYSICS,2014,566(0):0.
APA	Yang, Rui-zhi,de Ona Wilhelmi, Emma,&Aharonian, Felix.(2014).Probing cosmic rays in nearby giant molecular clouds with the Fermi Large Area Telescope.ASTRONOMY & ASTROPHYSICS,566(0),0.
MLA	Yang, Rui-zhi,et al."Probing cosmic rays in nearby giant molecular clouds with the Fermi Large Area Telescope".ASTRONOMY & ASTROPHYSICS 566.0(2014):0.