Microlensing of the broad-line region in the quadruply imaged quasar HE0435-1223^⋆,⋆⋆

¹ FRS-FNRS, Institut d’Astrophysique, Université de Liège, Allée du 6 Août 17, B5c, 4000 Liège, Belgium
e-mail: lbraibant@ulg.ac.be
² Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany
³ Departamento de Ciencias Fisicas, Universidad Andres Bello, Av. Republica 252, 8370251 Santiago, Chile
⁴ Instituto de Astrofísica Pontificia Universidad Católica de Chile, 4860 Avenida Vicuña Mackenna, Santiago, Chile

Received: 13 February 2014
Accepted: 10 April 2014

Abstract

Using infrared spectra of the z = 1.693 quadruply lensed quasar HE0435-1223 acquired in 2009 with the spectrograph SINFONI at the ESO Very Large Telescope, we have detected a clear microlensing effect in images A and D. While microlensing affects the blue and red wings of the Hα line profile in image D very differently, it de-magnifies the line core in image A. The combination of these different effects sets constraints on the line-emitting region; these constraints suggest that a rotating ring is at the origin of the Hα line. Visible spectra obtained in 2004 and 2012 indicate that the MgII line profile is microlensed in the same way as the Hα line. Our results therefore favour flattened geometries for the low-ionization line-emitting region, for example, a Keplerian disk. Biconical models cannot be ruled out but require more fine-tuning. Flux ratios between the different images are also derived and confirm flux anomalies with respect to estimates from lens models with smooth mass distributions.