title: Studying the Radiative Response of Circumnuclear Dust of AGNs
creator: Schnülle, Kirsten
subject: ddc-500
subject: 500 Natural sciences and mathematics
subject: ddc-520
subject: 520 Astronomy and allied sciences
subject: ddc-530
subject: 530 Physics
description: Radius measurements of dust tori around the central engine of luminous active galaxies  open up the possibility of probing cosmological models out to redshifts beyond where supernovae  can be used. Yet, the value of dust tori as standard candles is constrained by  the substantial intrinsic scatter in the size-luminosity relation found for samples of AGNs.  Indicated by single objects, a probable cause of this scatter is a non-trivial variation in the  dust location with the luminosity of the central engine, due to sublimation events and subsequent  long-term reformation of the hot dust surface radiating at near-infrared wavelengths.  In this work, I developed a refined dust reverberation model allowing to measure torus  sizes and additional observables characterizing the temperature state, stability, and distribution  of the innermost, hot dust in AGNs.  Optical to near-infrared photometric data were observed for 24 type 1 AGNs. Of these, I  have analyzed the Seyfert 1 galaxies NGC 4151, Ark 120, NGC 5548, and NGC 3227. The  derived inner torus radii fit very well into the established size-luminosity relation. While  three objects are well-described by a standard model without sublimation, the data of one  object could be fit satisfactorily only after allowing for dust sublimation events in the model.
date: 2017
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/23301/1/Thesis_KSchnuelle_final.pdf
identifier: DOI:10.11588/heidok.00023301
identifier: urn:nbn:de:bsz:16-heidok-233013
identifier:   Schnülle, Kirsten  (2017) Studying the Radiative Response of Circumnuclear Dust of AGNs.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/23301/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng