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A dark cloud associated with an unidentified EGRET source
Author(s) -
Oka T.,
Kawai N.,
Naito T.,
Horiuchi T.,
Namiki M.,
Saito Y.,
Romani R.W.,
Kifune T.
Publication year - 1999
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/1521-3994(199908)320:4/5<327::aid-asna327>3.0.co;2-s
Subject(s) - library science , physics , humanities , philosophy , computer science
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)×104 M⊙ surrounding an X-ray synchrotron nebula, which was detected by the ASCA satellite within the error circle of 2EG J1811–2339. Molecular gas along Lynds 227 shows spatial anti-correlation with the X-ray synchrotron nebula, suggesting that the synchrotron nebula is interacting with the Lynds 227 cloud. We propose a γ-ray emission mechanism for 2EG J1811–2339: High energy electrons are injected from a rotation-powered pulsar and accelerated further in shock waves generated by the interaction with ambient matter. The high energy electrons move into the molecular cloud at Department of Physics, Faculty of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. Cosmic Radiation Laboratory, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan. Department of Physics, Faculty of Science, Chiba University, 1-33 Yayoicho, Inage, Chiba, Chiba 2630022, Japan. Department of Physics, Faculty of Science, Science University of Tokyo, 1-3 Kagurazaka, Shinjyuku, Tokyo 162-8601, Japan. Institute of Space and Astronautical Science (ISAS), 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-0022, Japan. Department of Physics, Stanford University, Stanford, CA 94305-4060, U.S.A. Institute for Cosmic Ray Research (ICRR), University of Tokyo, 3-2-1, Midoricho, Tanashi, Tokyo 1888502, Japan.