Spectropolarimetry of the 3.4 micron absorption feature in NGC 1068

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dc.creatorMason, R. E.
dc.creatorWright, G. S.
dc.creatorAdamson, A.
dc.creatorPendleton, Y.
dc.date2006-11-13
dc.date.accessioned2026-07-07T10:20:47Z
dc.date.available2026-07-07T10:20:47Z
dc.descriptionIn order to test the silicate-core/organic-mantle model of galactic interstellar dust, we have performed spectropolarimetry of the 3.4 micron C-H bond stretch that is characteristic of aliphatic hydrocarbons, using the nucleus of the Seyfert 2 galaxy, NGC 1068, as a bright, dusty background source. Polarization calculations show that, if the grains in NGC 1068 had the properties assigned by the core-mantle model to dust in the galactic diffuse ISM, they would cause a detectable rise in polarization over the 3.4 micron feature. No such increase is observed. We discuss modifications to the basic core-mantle model, such as changes in grain size or the existence of additional non-hydrocarbon aligned grain populations, which could better fit the observational evidence. However, we emphasize that the absence of polarization over the 3.4 micron band in NGC 1068 - and, indeed, in every line of sight examined to date - can be readily explained by a population of small, unaligned carbonaceous grains with no physical connection to the silicates.
dc.descriptionApJ, accepted
dc.identifierhttps://arxiv.org/abs/astro-ph/0611374
dc.identifierhttp://arxiv.org/abs/astro-ph/0611374
dc.identifierAstrophys.J.656:798-804,2007
dc.identifierdoi:10.1086/510608
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/174963
dc.subjectAstrophysics
dc.titleSpectropolarimetry of the 3.4 micron absorption feature in NGC 1068
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