Reverberation Mapping Data of NGC 5548 Imply a Multicomponent Broad-line Region

Line broadening and variability are observational hallmarks of active galactic nuclei (AGN) which allow us to measure supermassive black hole masses as well as constrain the geometry and kinematics of the emitting gas, with the most precise measurements requiring a degree of modeling. Two popular mo...

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Main Authors: Kirk Long, Jason Dexter
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
Subjects:
Online Access:https://doi.org/10.3847/1538-4357/adda38
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author Kirk Long
Jason Dexter
author_facet Kirk Long
Jason Dexter
author_sort Kirk Long
collection DOAJ
description Line broadening and variability are observational hallmarks of active galactic nuclei (AGN) which allow us to measure supermassive black hole masses as well as constrain the geometry and kinematics of the emitting gas, with the most precise measurements requiring a degree of modeling. Two popular models of the broad-line region (BLR) describe the emitting gas as either a distribution of puffed-up clouds or a thin disk with strong velocity gradients. As we show in this work, key features in the reverberation mapping data set obtained by the AGN-STORM team in NGC 5548 cannot be accounted for by either simple model. In several emission lines the observed broad-line profile has a single peak yet the delay profile has a distinct double peak, strongly motivating a BLR with emission from multiple components. We demonstrate a few possibilities that may alleviate the tension and better represent the true nature of the broad-line-emitting gas in NGC 5548 and beyond.
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spelling doaj-art-d80b41a9c19b4e55b8fe01ff701367372025-08-20T03:50:01ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01987219610.3847/1538-4357/adda38Reverberation Mapping Data of NGC 5548 Imply a Multicomponent Broad-line RegionKirk Long0https://orcid.org/0009-0003-8293-2185Jason Dexter1https://orcid.org/0000-0003-3903-0373JILA, University of Colorado Boulder , USA ; kirk.long@colorado.eduJILA, University of Colorado Boulder , USA ; kirk.long@colorado.eduLine broadening and variability are observational hallmarks of active galactic nuclei (AGN) which allow us to measure supermassive black hole masses as well as constrain the geometry and kinematics of the emitting gas, with the most precise measurements requiring a degree of modeling. Two popular models of the broad-line region (BLR) describe the emitting gas as either a distribution of puffed-up clouds or a thin disk with strong velocity gradients. As we show in this work, key features in the reverberation mapping data set obtained by the AGN-STORM team in NGC 5548 cannot be accounted for by either simple model. In several emission lines the observed broad-line profile has a single peak yet the delay profile has a distinct double peak, strongly motivating a BLR with emission from multiple components. We demonstrate a few possibilities that may alleviate the tension and better represent the true nature of the broad-line-emitting gas in NGC 5548 and beyond.https://doi.org/10.3847/1538-4357/adda38Active galactic nuclei
spellingShingle Kirk Long
Jason Dexter
Reverberation Mapping Data of NGC 5548 Imply a Multicomponent Broad-line Region
The Astrophysical Journal
Active galactic nuclei
title Reverberation Mapping Data of NGC 5548 Imply a Multicomponent Broad-line Region
title_full Reverberation Mapping Data of NGC 5548 Imply a Multicomponent Broad-line Region
title_fullStr Reverberation Mapping Data of NGC 5548 Imply a Multicomponent Broad-line Region
title_full_unstemmed Reverberation Mapping Data of NGC 5548 Imply a Multicomponent Broad-line Region
title_short Reverberation Mapping Data of NGC 5548 Imply a Multicomponent Broad-line Region
title_sort reverberation mapping data of ngc 5548 imply a multicomponent broad line region
topic Active galactic nuclei
url https://doi.org/10.3847/1538-4357/adda38
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AT jasondexter reverberationmappingdataofngc5548implyamulticomponentbroadlineregion