THE FLUORESCENCE-DOMINATED X-RAY-SPECTRUM OF THE SPIRAL GALAXY NGC-6552

A hard X-ray source with a 2-10 keV flux of similar to 6 x 10(-13) erg s s(-1) cm(-2) was detected with ASCA in the north ecliptic pole regio n. It is identified with the spiral galaxy NGC 6552 at a redshift of z = 0.026, which is optically classified as a Seyfert 2 galaxy. The X-r ay spectrum consists of a series of atomic K-emission lines from (near ly-) neutral species of at least seven abundant elements, and a heavil y absorbed (N-H similar to 6 X 10(23) cm(-2)) hard continuum. The iron line has an equivalent width as large as similar to 0.9 keV. Our resu lts show that NGC 6552 is an extreme type 2 Seyfert galaxy, in which t he fluorescent lines are produced when hard X-rays from a hidden activ e nucleus are reflected off thick cool matter into our line of sight. The intrinsic 2-10 keV luminosity of the nucleus is estimated to be at least 6 x 10(42) ergs s(-1).