A dark cloud associated with an unidentified EGRET source

被引：25

作者：

Oka, T

Kawai, N

Naito, T

Horiuchi, T

Namiki, M

Saito, Y

Romani, RW

Kifune, T

机构：

[1] Univ Tokyo, Fac Sci, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan

[2] RIKEN, Inst Phys & Chem Res, Cosm Radiat Lab, Wako, Saitama 3510198, Japan

[3] Natl Astron Observ, Mitaka, Tokyo 1818588, Japan

[4] Chiba Univ, Fac Sci, Dept Phys, Chiba 2639022, Japan

[5] Sci Univ Tokyo, Fac Sci, Dept Phys, Shinjyuku Ku, Tokyo 1628601, Japan

[6] Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2290022, Japan

[7] Stanford Univ, Dept Phys, Stanford, CA 94305 USA

[8] Univ Tokyo, Inst Cosm Ray Res, Tanashi, Tokyo 1888502, Japan

来源：

ASTROPHYSICAL JOURNAL | 1999年 / 526卷 / 02期

关键词：

gamma rays : theory; ISM : clouds; ISM : individual (Lynds 227); ISM : molecules; pulsars : individual (2EG J1811-2339);

D O I：

10.1086/308014

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

CO J = 1-0 mapping observations of the dark nebula Lynds 227, which is possibly associated with the unidentified EGRET source 2EG J1811-2339, are presented. We detected a large amount of molecular gas along Lynds 227 with a total mass of (1-2) x 10(4) M-circle dot surrounding an X-ray synchrotron nebula, which was detected by the ASCA within the error circle of 2EG J1811-2339. Molecular gas along Lynds 227 shows spatial anticorrelation with the X-ray synchrotron nebula, suggesting that the synchrotron nebula is interacting with the Lynds 227 cloud. We propose a gamma-ray emission mechanism for 2EG J1811-2339: high-energy electrons are injected from a rotation-powered pulsar and further accelerated in shock waves generated by the interaction with ambient matter. The high-energy electrons move into the molecular cloud at the Lynds 227 and collide with dense interstellar matter to yield high-energy gamma-ray photons, mainly through relativistic bremsstrahlung.

引用

页码：764 / 771

页数：8

共 38 条

[1] On the mechanisms of gamma radiation in the Crab Nebula [J].