Reverberation and photoionization estimates of the broad-line region radius in low-z quasars

Black hole mass estimation in quasars, especially at high redshift, involves the use of single-epoch spectra with signal-to-noise ratio and resolution that permit accurate measurement of the width of a broad line assumed to be a reliable virial estimator. Coupled with an estimate of the radius of th...

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Detalles Bibliográficos
Autores: Negrete, C. Alenka, Dultzin, Deborah, Marziani, Paola, Sulentic, Jack W.
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2013
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/407198
Acceso en línea:http://hdl.handle.net/10261/407198
Access Level:acceso abierto
Palabra clave:Black hole physics
Galaxies: active
Quasars: emission lines
Quasars: general
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spelling Reverberation and photoionization estimates of the broad-line region radius in low-z quasarsNegrete, C. AlenkaDultzin, DeborahMarziani, PaolaSulentic, Jack W.Black hole physicsGalaxies: activeQuasars: emission linesQuasars: generalBlack hole mass estimation in quasars, especially at high redshift, involves the use of single-epoch spectra with signal-to-noise ratio and resolution that permit accurate measurement of the width of a broad line assumed to be a reliable virial estimator. Coupled with an estimate of the radius of the broad-line region (BLR) this yields the black hole mass M BH. The radius of the BLR may be inferred from an extrapolation of the correlation between source luminosity and reverberation-derived r BLR measures (the so-called Kaspi relation involving about 60 low-z sources). We are exploring a different method for estimating r BLR directly from inferred physical conditions in the BLR of each source. We report here on a comparison of r BLR estimates that come from our method and from reverberation mapping. Our "photoionization" method employs diagnostic line intensity ratios in the rest-frame range 1400-2000 Å (Al III λ1860/Si III] λ1892, C IV λ1549/Al III λ1860) that enable derivation of the product of density and ionization parameter with the BLR distance derived from the definition of the ionization parameter. We find good agreement between our estimates of the density, ionization parameter, and r BLR and those from reverberation mapping. We suggest empirical corrections to improve the agreement between individual photoionization-derived r BLR values and those obtained from reverberation mapping. The results in this paper can be exploited to estimate M BH for large samples of high-z quasars using an appropriate virial broadening estimator. We show that the width of the UV intermediate emission lines are consistent with the width of Hβ, thereby providing a reliable virial broadening estimator that can be measured in large samples of high-z quasars. © 2013. The American Astronomical Society. All rights reserved.A. Negrete and D. Dultzin acknowledge support from grant IN111610 PAPIIT UNAM, and Yair Krongold for fruitful discussions. J.W.S. acknowledges support under a Proyecto de Excelencia contract from La Junta de AndalucaPeer reviewedIOP PublishingUniversidad Nacional Autónoma de MéxicoJunta de AndalucíaConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2025202520132025info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Postprintinfo:eu-repo/semantics/acceptedVersionhttp://hdl.handle.net/10261/407198reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://dx.doi.org/10.1088/0004-637X/771/1/31Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/4071982026-05-22T06:33:51Z
dc.title.none.fl_str_mv Reverberation and photoionization estimates of the broad-line region radius in low-z quasars
title Reverberation and photoionization estimates of the broad-line region radius in low-z quasars
spellingShingle Reverberation and photoionization estimates of the broad-line region radius in low-z quasars
Negrete, C. Alenka
Black hole physics
Galaxies: active
Quasars: emission lines
Quasars: general
title_short Reverberation and photoionization estimates of the broad-line region radius in low-z quasars
title_full Reverberation and photoionization estimates of the broad-line region radius in low-z quasars
title_fullStr Reverberation and photoionization estimates of the broad-line region radius in low-z quasars
title_full_unstemmed Reverberation and photoionization estimates of the broad-line region radius in low-z quasars
title_sort Reverberation and photoionization estimates of the broad-line region radius in low-z quasars
dc.creator.none.fl_str_mv Negrete, C. Alenka
Dultzin, Deborah
Marziani, Paola
Sulentic, Jack W.
author Negrete, C. Alenka
author_facet Negrete, C. Alenka
Dultzin, Deborah
Marziani, Paola
Sulentic, Jack W.
author_role author
author2 Dultzin, Deborah
Marziani, Paola
Sulentic, Jack W.
author2_role author
author
author
dc.contributor.none.fl_str_mv Universidad Nacional Autónoma de México
Junta de Andalucía
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Black hole physics
Galaxies: active
Quasars: emission lines
Quasars: general
topic Black hole physics
Galaxies: active
Quasars: emission lines
Quasars: general
description Black hole mass estimation in quasars, especially at high redshift, involves the use of single-epoch spectra with signal-to-noise ratio and resolution that permit accurate measurement of the width of a broad line assumed to be a reliable virial estimator. Coupled with an estimate of the radius of the broad-line region (BLR) this yields the black hole mass M BH. The radius of the BLR may be inferred from an extrapolation of the correlation between source luminosity and reverberation-derived r BLR measures (the so-called Kaspi relation involving about 60 low-z sources). We are exploring a different method for estimating r BLR directly from inferred physical conditions in the BLR of each source. We report here on a comparison of r BLR estimates that come from our method and from reverberation mapping. Our "photoionization" method employs diagnostic line intensity ratios in the rest-frame range 1400-2000 Å (Al III λ1860/Si III] λ1892, C IV λ1549/Al III λ1860) that enable derivation of the product of density and ionization parameter with the BLR distance derived from the definition of the ionization parameter. We find good agreement between our estimates of the density, ionization parameter, and r BLR and those from reverberation mapping. We suggest empirical corrections to improve the agreement between individual photoionization-derived r BLR values and those obtained from reverberation mapping. The results in this paper can be exploited to estimate M BH for large samples of high-z quasars using an appropriate virial broadening estimator. We show that the width of the UV intermediate emission lines are consistent with the width of Hβ, thereby providing a reliable virial broadening estimator that can be measured in large samples of high-z quasars. © 2013. The American Astronomical Society. All rights reserved.
publishDate 2013
dc.date.none.fl_str_mv 2013
2025
2025
2025
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Postprint
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/407198
url http://hdl.handle.net/10261/407198
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv http://dx.doi.org/10.1088/0004-637X/771/1/31
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv IOP Publishing
publisher.none.fl_str_mv IOP Publishing
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,811543

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