Unabsorbed Seyfert 2 galaxies: the case of ‘naked’ AGN

摘要: Hawkins reported on a class of 'naked' active galactic nuclei (AGN) characterized by strong amplitude optical brightness variability and the complete absence broad emission lines in spectrum. The suggests that nucleus is seen directly, however contradicts simple formulation Unified Models for AGN. We present results quasi-simultaneous spectroscopic observations with XMM―Newton New Technology Telescope (NTT) (La Silla) two confirm nature Q2131-427 which no line components have been detected spectrum its X-ray shows signs intrinsic absorption. mismatch this source cannot be ascribed to high nuclear dust-to-gas ratio Compton-thick ruled out basis F X /F [O III] ratio. broad-line region (BLR) may completely absent source, possibly as consequence low Eddington On other hand, Q2130-431 Hα Hβ components, revealing presence BLR. A mild absorption expected intermediate type 1.8 Seyfert galaxies like Q2130-431, we put very upper limit column density (<2 x 10 20 cm ―2 ), also Balmer decrement BLR itself does not suffer from reddening. propose object intrinsically weak, making case 'true' galaxy. report detection Abell 3783 galaxy cluster field view observation.