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For refcode 1997MNRAS.285..683I:
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Copyright by Royal Astronomical Society. 1997MNRAS.285..683I ASCA PV observations of the Seyfert 2 galaxy NGC 4388: the obscured nucleus and its X-ray emission K. Iwasawa, A. C. Fabian, S. Ueno, H. Awaki, Y. Fukazawa, K. Matsushita and K. MaKishima Accepted 1996 September 26. Received 1996 September 26; in original form 1996 August 28 ABSTRACT We present results on the Seyfert 2 galaxy NGC 4388 in the Virgo cluster observed with ASCA during its performance verification (PV) phase. The 0.5-10 keV X-ray spectrum consists of multiple components: (1) a continuum component heavily absorbed by a column density N_H_ ~4 x 10^23^ cm^-2^ above 3 keV; (2) a strong 6.4-keV line (equivalent width EW ~ 500 eV); (3) a weak flat continuum between 1 and 3 keV; and (4) excess soft X-ray emission below 1 keV. The detection of strong absorption for the hard X-ray component is firm evidence for an obscured active nucleus in this Seyfert 2 galaxy. The absorption-corrected X-ray luminosity is about 2 x 10^42^ erg s^-1^. This is the first time that the fluorescent iron K line has been detected in this object; the large EW is a common property of classical Seyfert 2 nuclei. The flat spectrum in the intermediate energy range may be a scattered continuum from the central source. The soft X-ray emission below 1 keV can be thermal emission from a temperature kT ~ 0.5 keV, consistent with the spatially extended emission observed by ROSAT HRI. However, the low abundance (Z ~ 0.05 Z_sun_) and high mass flow rate required for the thermal model and an iron K line stronger than expected from the obscuring torus model are puzzling. An alternative consistent solution can be obtained if the central source was a hundred times more luminous over a thousand years ago. All the X-ray emission below 3 keV is then scattered radiation. Key words: galaxies: active - galaxies: individual: NGC 4388 - galaxies: Seyfert - X-rays: galaxies.
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