Two-zone Diffusion of Electrons and Positrons from Geminga Explains the Positron Anomaly

doi:10.3847/1538-4357/aad092

CORC > 高能物理研究所 > 中国科学院高能物理研究所 > 粒子天体物理中心

	Two-zone Diffusion of Electrons and Positrons from Geminga Explains the Positron Anomaly
	Yin, PF; Bi, XJ; Fang, K; Yin PF(殷鹏飞); Bi XJ(毕效军); Fang K(方堃); Yuan, Q
刊名	ASTROPHYSICAL JOURNAL
	2018
卷号	863 期号:1 页码:30
关键词	cosmic rays ISM: individual objects (Geminga nebula) pulsars: individual (Geminga)
ISSN号	0004-637X
DOI	10.3847/1538-4357/aad092
文献子类	Article
英文摘要	The recent HAWC observations of a very-high-energy 7-ray halo around Geminga and Monogem indicate a very slow diffusion of cosmic rays that results in a tiny contribution of positrons from these two pulsars to the local flux. This makes the cosmic positron excess anomaly observed by PAMELA and AMS-02 even more puzzling. However, from the boron-to-carbon ratio data one can infer that the average diffusion coefficient in the Galaxy should be much larger. In this work we propose a two-zone diffusion model in which the diffusion is slow only in a small region around the source, outside of which the propagation is as fast as usual. We find that this scenario can naturally explain the positron excess data with parameters even more reasonable than those in the conventional one-zone diffusion model. The reason is that during the lifetime of Geminga (similar to 300 kyr), the electrons/positrons have propagated too far away with a fast diffusion and led to a low local flux. The slow-diffusion region in the two-zone model helps to confine the electrons/positrons for a long time and lead to an enhancement of the local flux. So under the constraint of the HAWC observations, pulsars are still the probable origin of the cosmic-ray positron excess.
电子版国际标准刊号	1538-4357
WOS关键词	GAMMA-RAY SOURCES ; GALACTIC PLANE ; COSMIC-RAYS ; PROPAGATION ; MILAGRO ; EARTH ; FLUX
WOS研究方向	Astronomy & Astrophysics
语种	英语
WOS记录号	WOS:000441197400004
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/286203]
专题	高能物理研究所_粒子天体物理中心
通讯作者	Fang K(方堃)
作者单位	中国科学院高能物理研究所
推荐引用方式 GB/T 7714	Yin, PF,Bi, XJ,Fang, K,et al. Two-zone Diffusion of Electrons and Positrons from Geminga Explains the Positron Anomaly[J]. ASTROPHYSICAL JOURNAL,2018,863(1):30.
APA	Yin, PF.,Bi, XJ.,Fang, K.,殷鹏飞.,毕效军.,...&Yuan, Q.(2018).Two-zone Diffusion of Electrons and Positrons from Geminga Explains the Positron Anomaly.ASTROPHYSICAL JOURNAL,863(1),30.
MLA	Yin, PF,et al."Two-zone Diffusion of Electrons and Positrons from Geminga Explains the Positron Anomaly".ASTROPHYSICAL JOURNAL 863.1(2018):30.