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X‐ray activities in the galactic center region
Author(s) -
Maeda Y.,
Koyama K.,
Imanishi K.,
Murakami H.,
Nishiuchi M.,
Sakano M.,
Tsujimoto M.,
Yokogawa J.,
Yamauchi S.
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<177::aid-asna177>3.0.co;2-g
Subject(s) - physics , galactic center , astrophysics , galaxy , stars , astronomy , luminosity , molecular cloud , center (category theory) , active galactic nucleus , chemistry , crystallography
With ASCA we obtained detailed X‐ray images and spectra of the Galactic Center. X‐rays in the central parsecs from the dynamical center of the Galaxy, Sgr A*, were dominated by extended emission. Since Sgr A* was not spatially resolved from the extended structure, an upper limit to its luminosity was found to be 3 × 10 35 erg s —1 . This result indicates that the current AGN activity of the Galactic nucleus is very low. In the central hundreds of parsecs, X‐ray stars, thin thermal diffuse plasma, and iron fluorescent emission from molecular clouds were seen. Based on the analyses of the X‐ray stars and both of the diffuse components, we discuss some features which are possibly related to past nuclear activities.