Clumpy winds and the obscuration of Active Galactic Nuclei

dc.creatorNayakshin, Sergei
dc.creatorCuadra, Jorge
dc.date2006-02-16
dc.date.accessioned2026-07-07T10:27:51Z
dc.date.available2026-07-07T10:27:51Z
dc.descriptionThe role of star-formation driven outflows in the obscuration of the central source in the Active Galactic Nuclei (AGN) is discussed. The outflow from a sub-parsec scale accretion disc is numerically modelled for parameters appropriate to the Galactic Centre. The resulting obscuration pattern is very patchy, with some lines of sight becoming optically thick to Thomson scattering. A fixed observer would see column depth changing by factors of many over time scales of order months to hundreds of years, depending on the physical size of the outflow region. Such winds may be relevant for obscuration of some AGN and especially "changing look AGN". However, averaged over the sky as seen from the central source, these winds are always optically thin unless wind outflow rates are super-Eddington. A simple scaling argument shows that this is true not only for stellar-driven winds but for any AGN winds. We therefore conclude that AGN winds are unable to account for the vast majority of optically thick obscured AGN (a significant fraction of all AGN). We suggest that the most likely source of optically thick obscuration in AGN is a warped parsec scale accretion disc.
dc.description5 pages, 5 colour figures. Submitted to MNRAS
dc.identifierhttps://arxiv.org/abs/astro-ph/0602366
dc.identifierhttp://arxiv.org/abs/astro-ph/0602366
dc.identifierAstron.Astrophys.465:119-124,2007
dc.identifierdoi:10.1051/0004-6361:20065541
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/177274
dc.subjectAstrophysics
dc.titleClumpy winds and the obscuration of Active Galactic Nuclei
dc.typetext

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