H. Awaki, H. Kunieda, Y. Tawara, and K. Koyama

Abstract

An obscured nucleus was discovered in Seyfert 2 galaxy NGC 4507 with the Ginga satellite. The 2-10 keV X-ray luminosity is 3.2 x 10 exp 43 erg/s, and the continuum radiation is well described by a power law model with a photon index of 1.34 + 0.28/-0.25. The column density of the obscuring matter is (4.9 +/-0.7) x 10 exp 23/sq cm, which is sufficiently thick to hide the broad-line region and the nucleus. An iron line with equivalent width of 420 + 100/-110 eV has also been detected in the X-ray spectrum. In order to explain the large equivalent width, a large covering factor for the matter around the nucleus is needed. The obscuration can be naturally explained in terms of a torus in the unified Seyfert model.