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Discovery of an obscured low luminosity active nucleus in the spiral galaxy NGC 4258The spectra and images of the nearby jet galaxy NGC 4258 (M106) obtained with ASCA indicate presence of several distinct X-ray emission components. The emission above 3 keV is pointlike and coincident in position with the optical nucleus, exhibiting a hard (photon index approximately 1.78) and absorbed N(sub H) approximately 1.5 x 10(exp 23) cm(exp -2) spectrum. This provides clear evidence that NGC 4258 hosts an obscured active nucleus of low luminosity, about 4 x 10(exp 40) ergs s(exp -1) in 2-10 keV after removing the absorption. Iron K-line emission with an equivalent width 0.25 +/- 0.10 keV was detected. The emission below 1 keV is dominated by an extended approximately 4 min thin-thermal component with a temperature approximately 0.5 keV exhibiting atomic emission lines, possibly associated with the jet. There exists a third continuum component with an intermediate spectral hardness, which is brightest at approximately 1 min south-east of the nucleus.
Document ID
19950033366
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Makishima, Kazuo
(Univ. of Tokyo Tokyo, Japan)
Fujimoto, Ryuichi
(Institute of Space and Astronautical Science Sagamihara, Japan)
Ishisaki, Yoshitaka
(Univ. of Tokyo Tokyo, Japan)
Kii, Tsuneo
(Institute of Space and Astronautical Science Sagamihara, Japan)
Loewenstein, Michael
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mushotzky, Richard
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Serlemitsos, Peter
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Sonobe, Takashi
(Institute of Space and Astronautical Science Sagamihara, Japan)
Tashiro, Makoto
(Univ. of Tokyo Tokyo, Japan)
Yaqoob, Tahir
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1994
Publication Information
Publication: PASJ: Publications of the Astronomical Society of Japan
Volume: 46
Issue: 3
ISSN: 0004-6264
Subject Category
Astrophysics
Accession Number
95A64965
Distribution Limits
Public
Copyright
Other

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