Título

Reverberation and photoionization estimates of the Broad Line Region Radius in Low-z Quasars

Autor

CASTALIA ALENKA NEGRETE PEÑALOZA

Nivel de Acceso

Acceso Abierto

Licencia

http://creativecommons.org/licenses/by-nc-nd/4.0

Materias

Galaxies: active - (INSPEC) Quasars: general - (INSPEC) Quasars: emission lines - (INSPEC) Black holes: physics - (INSPEC) CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA - (CTI) ASTRONOMÍA Y ASTROFÍSICA - (CTI) ASTRONOMÍA Y ASTROFÍSICA - (CTI)

Resumen o descripción

Black Hole Mass estimation in quasars, especially at high redshift, involves use of single epoch spectra with s/n 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 this yields MMB· The radius of the broad line region (BLR) may be inferred from an extrapolation of the correlation between source luminosity and reverberation derived rBLR measures (the so-called Kaspi relation involving about 60 low z sources). We are exploring a different method for estimating rBLR directly from inferred physical conditions in the BLR of each source. We report here on a comparison of rBLR 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 (AlIIIλ1860/ SiIII]λ1892, Civλ1549/AlIIIλ1860) 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 rBLR and those from reverberation mapping. We suggest empirical corrections to improve the agreement between individual photoionization-derived rBLR values and those obtained from reverberation mapping. The results in this paper can be exploited to estimate black hole masses MBH 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, therefore providing a reliable virial broadening estimator that can be measured in large samples of high-z quasars.

Editor

The Astrophysical Journal

Fecha de publicación

20 de mayo de 2013

Tipo de publicación

Artículo

Versión de la publicación

Versión aceptada

Recurso de información

http://inaoe.repositorioinstitucional.mx/jspui/handle/1009/2254

Formato

application/pdf

Idioma

Inglés

Audiencia

Estudiantes

Investigadores

Público en general

Sugerencia de citación

Alenka Negrete, C., et al., (2013), Reverberation and photoionization estimates of the Broad Line Region Radius in Low-z Quasars, The Astrophysical Journal, Vol. 771(1):1-33

Repositorio Orígen

Repositorio Institucional del INAOE

Descargas

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