X-ray absorption in Seyfert 2 galaxies |
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| Authors: | M Guainazzi F Fiore G Matt GC Perola |
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| Institution: | 1Astrophysics Division, Space Science Department of ESA, ESTEC, Postbus 299, NL-2200 AG Noordwijk, the Netherlands;2XMM Science Operation Center, VILSPA-ESA, Apartado 50727, E-28080 Madrid, Spain;3Osservatorio Astronomico di Roma, Via dell'Osservatorio, I-00144 Monteporzio Catone, Italy;4BeppoSAX Science Data Center, Via Corcolle 19, I-00131 Roma, Italy;5Dipartimento di Fisica, Universitàdegli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma, Italy |
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| Abstract: | We have studied the correlation among X-ray absorption, optical reddening and nuclear dust morphology in Seyfert 2 galaxies. Two main conclusions emerge: (i) the Balmer decrement and the amount of X-ray absorption are anticorrelated over a wide range of column density,  – the correlation no longer applies to Compton-thick objects  , although they span a comparable range in Balmer decrement; (ii) Compton-thin Seyfert 2s seem to prefer nuclear environments, which are rich in dust on scales of hundreds of parsecs. On the other hand, Compton-thick Seyferts indifferently exhibit 'dust-poor' and 'dust-rich' environments. These results support an extension of the Seyfert unification scenario (as recently proposed by Matt ), where Compton-thick Seyfert 2s are observed through compact 'torii', whereas Compton-thin ones are obscured by dust on much larger scales. |
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| Keywords: | galaxies: active galaxies: ISM galaxies: nuclei galaxies: Seyfert X-rays: galaxies |
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