MEASURING BLACK HOLE MASSES IN ACTIVE GALACTIC NUCLEI USING THE POLARIZATION OF BROAD EMISSION LINES

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MEASURING BLACK HOLE MASSES IN ACTIVE GALACTIC NUCLEI USING THE POLARIZATION OF BROAD EMISSION LINES

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dc.contributor.advisor Popović, Luka
dc.contributor.author Savić, Đorđe
dc.date.accessioned 2019-12-25T17:23:02Z
dc.date.available 2019-12-25T17:23:02Z
dc.date.issued 2019
dc.identifier.uri http://hdl.handle.net/123456789/4821
dc.description.abstract Supermassive black holes (SMBHs) reside in the heart of nearly every massive galaxy in the Universe. Most of them lie dormant, but when the nearby gas is abundant, it will enter an active phase and form an active galactic nucleus (AGN). In their active phase, SMBHs have a profound effect on the host galaxy evolution and its environment. Reliable SMBH mass measuring is therefore an important task in modern astronomy. For that purpose, a method has been recently proposed by Afanasiev & Popović (2015) that uses the rotation of the polarization plane position angle across the broad emission line profile in order to trace the Keplerian motion and determine the SMBH mass. This method assumes that broad lines are emitted from a flattened disk-like region undergoing Keplerian motion, while the polarization is mainly due to the light scattering of the inner side of the coplanar dusty torus – the equatorial scattering. The goal of the thesis is to theoretically explore the possibilities of this method. We performed numerous Monte Carlo simulations for modeling equatorial scattering in AGNs using the radiative transfer code stokes (Goosmann & Gaskell 2007). We included complex motion of the emitting region in the form of radial inflows, vertical outflows, or due to the presence of the supermassive binary black holes (SMBBHs). We also selected fourwell known AGNs for observations: NGC4051, NGC4151, 3C273 and PG0844+349. Spectropolarimetry was done with the 6m telescope BTA of the Special Astrophysical Observatory of the Russian Academy of Science (SAO RAS) with the focal reducer SCORPIO. We modeled each of these AGNs using observational data available from the literature, and we compared the results of our models with observational data. We find that this method can be used as a new independent way to measure the SMBH masses in AGNs. The influence of the inflows and the outflows can be ignored if they are much lower than the Keplerian velocity. Additionally, when the scattering region is close to the broad line region, this method becomes independent of the viewing inclination. For SMBBHs, this method cannot be used, however, we obtained unique polarization profiles which are not common for a single SMBH, which could be used for identifying possible SMBBH candidates. SMBH mass estimates for the four observed AGNs are in good agreement with the masses obtained using other methods, such as the method of reverberation mapping. Method for independent SMBH mass measurements has been theoretically and experimentally verified in this work, which is very important for the future research that is dealing with the SMBH influence on its immediate environment. en_US
dc.description.provenance Submitted by Slavisha Milisavljevic (slavisha) on 2019-12-25T17:23:02Z No. of bitstreams: 1 teza_Djordje_Savic.pdf: 13418154 bytes, checksum: a3d40c39fe76c66192633047b02877b8 (MD5) en
dc.description.provenance Made available in DSpace on 2019-12-25T17:23:02Z (GMT). No. of bitstreams: 1 teza_Djordje_Savic.pdf: 13418154 bytes, checksum: a3d40c39fe76c66192633047b02877b8 (MD5) Previous issue date: 2019 en
dc.language.iso en en_US
dc.publisher Beograd en_US
dc.title MEASURING BLACK HOLE MASSES IN ACTIVE GALACTIC NUCLEI USING THE POLARIZATION OF BROAD EMISSION LINES en_US
mf.author.birth-date 1990
mf.author.birth-place Kragujevac en_US
mf.author.birth-country Srbija en_US
mf.author.residence-state Srbija en_US
mf.author.citizenship Srpsko en_US
mf.author.nationality Srbin en_US
mf.subject.area Astronomy en_US
mf.subject.keywords Active Galactic Nuclei, supermassive black holes, polarization, radiative transfer en_US
mf.subject.subarea Astrophysics en_US
mf.contributor.committee Goosmann, Rene
mf.contributor.committee Hameury, Jean-Marie
mf.contributor.committee Ilić, Dragana
mf.contributor.committee Gratadour, Damien
mf.contributor.committee Boisson, Catherine
mf.contributor.committee Stalevski, Marko
mf.university.faculty Mathematical faculty en_US
mf.document.pages 152 en_US
mf.document.location Beograd en_US
mf.document.genealogy-project No en_US
mf.university Belgrade University en_US

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