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Discovery of an obscured low luminosity active nucleus in the spiral galaxy NGC 4258
- Source :
- PASJ: Publications of the Astronomical Society of Japan. 46(3)
- Publication Year :
- 1994
- Publisher :
- United States: NASA Center for Aerospace Information (CASI), 1994.
-
Abstract
- The 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.
- Subjects :
- Astrophysics
Subjects
Details
- Language :
- English
- ISSN :
- 00046264
- Volume :
- 46
- Issue :
- 3
- Database :
- NASA Technical Reports
- Journal :
- PASJ: Publications of the Astronomical Society of Japan
- Publication Type :
- Report
- Accession number :
- edsnas.19950033366
- Document Type :
- Report