ASCA OBSERVATIONS OF THE SEYFERT-2 GALAXY NGC-7582 - AN OBSCURED AND SCATTERED VIEW OF THE HIDDEN NUCLEUS

ASCA observations of the Seyfert 2 galaxy NGC 7582 revealed that it wa s highly variable on the timescale of similar to 2 x 10(4) s in the ha rd X-ray band (2-10 keV), while the soft X-ray (0.5-2 keV) flux remain ed constant during the observations. The normalized variability amplit ude in the hard X-ray band was sigma(RMS) approximate to 0.3, which is the same level as that of Seyfert 1 galaxies of the same luminosity s imilar to 3 x 10(42) erg s(-1) (2-10 keV). The spectral analysis sugge sts that this object is seen through an obscuring torus with the thick ness of N-H similar to 1.0 x 10(23)cm(-2). The hard X-rays are an abso rbed direct continuum from a hidden Seyfert 1 nucleus, while the soft X-rays are dominated by the scattered central continuum from an extend ed spatial region. We have an obscured/absorbed and a scattered view o f this source as expected from the unification model for Seyfert galax ies. More interestingly, the inferred column density increased by simi lar to 4 x 10(22)cm(-2) from 1994 to 1996, suggesting a ''patchy'' tor us structure, namely the torus might be composed of many individual cl ouds. The observed iron-line feature near 6.4 keV with the equivalent width of 170 eV is also consistent with the picture of the transmissio n of nuclear X-ray continuum through a non-uniform torus.