Microlensing of Quasar Broad Emission Lines: Constraints on Broad Line Region Size

Falco, E.; Motta, V.; Muñoz, J. A.; Kochanek, C. S.; Jimenez-Vicente, J.; Mediavilla, E.; Guerras, E.
Bibliographical reference

The Astrophysical Journal, Volume 764, Issue 2, article id. 160, 9 pp. (2013).

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2
2013
Number of authors
7
IAC number of authors
2
Citations
74
Refereed citations
69
Description
We measure the differential microlensing of the broad emission lines between 18 quasar image pairs in 16 gravitational lenses. We find that the broad emission lines are in general weakly microlensed. The results show, at a modest level of confidence (1.8σ), that high ionization lines such as C IV are more strongly microlensed than low ionization lines such as Hβ, indicating that the high ionization line emission regions are more compact. If we statistically model the distribution of microlensing magnifications, we obtain estimates for the broad line region size of rs = 24+22 –15 and rs = 55+150 –35 lt-day (90% confidence) for the high and low ionization lines, respectively. When the samples are divided into higher and lower luminosity quasars, we find that the line emission regions of more luminous quasars are larger, with a slope consistent with the expected scaling from photoionization models. Our estimates also agree well with the results from local reveberation mapping studies.
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Relativistic and Theoretical Astrophysics
Introduction Gravitational lenses are a powerful tool for Astrophysics and Cosmology. The goals of this project are: i) to obtain a robust determination of the Hubble constant from the time delay measured between the images of a lensed quasar; ii) to study the individual and statistical properties of dark matter condensations in lens galaxies from
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