The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. http://dspace-roma3.caspur.it:80 2013-06-18T22:17:28Z 2013-06-18T22:17:28Z Bianchi, Stefano Piconcelli, Enrico Chiaberge, Marco Jimenez Bailon, Elena Matt, Giorgio Fiore, Fabrizio http://hdl.handle.net/2307/325 2011-12-22T13:35:27Z 2009-03-31T22:00:00Z

<Title>How complex is the obscuration in active galactic nuclei? new cluesfrom the suzaku monitoring of the x-ray absorbers in ngc 7582</Title> <Authors>Bianchi, Stefano; Piconcelli, Enrico; Chiaberge, Marco; Jimenez Bailon, Elena; Matt, Giorgio; Fiore, Fabrizio</Authors> <Issue Date>2009-04</Issue Date> <Is part of>Astrophysical Journal</Is part of> <Volume>695</Volume> <Pages>781-787</Pages> <Abstract>We present the results of a Suzaku monitoring campaign of the Seyfert 2galaxy, NGC 7582. The source is characterized by very rapid (ontimescales even lower than a day) changes of the column density of aninner absorber, together with the presence of constant componentsarising as reprocessing from a Compton-thick material. The best-fittingscenario implies important modifications to the zeroth-order view ofUnified Models. While the existence of a pc-scale torus is needed inorder to produce a constant Compton reflection component and an ironKa-emission line, in this Seyfert 2 galaxy this is not viewed along theline of sight. On the other hand, the absorption of the primarycontinuum is due to another material, much closer to the black hole,roughly at the distance of the broad-line region, which can produce theobserved rapid spectral variability. On top of that, the constantpresence of a 10(22) cm(-2) column density can be ascribed to thepresence of a dust lane, extended on a galactic scale, as previouslyconfirmed by Chandra. There is now mounting evidence that complexity inthe obscuration of active galactic nuclei (AGNs) may be the rule ratherthan the exception. We therefore propose to modify the UnificationModel, adding to the torus the presence of two furtherabsorbers/emitters. Their combination along the line of sight canreproduce all the observed phenomenology.</Abstract>

2009-03-31T22:00:00Z