Probing the structure of the lensed quasar SDSSJ1004+4112 through microlensing analysis of spectroscopic data
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Fian, C.; Muñoz Lozano, José Antonio; Forés Toribio, R.; Mediavilla, Evencio; Jiménez Vicente, Jorge; Chelouche, D.; Kaspi, S.; Richards, G. T.Editorial
EDP Sciences
Materia
Gravitational lensing: strong Gravitational lensing: micro Quasars: general
Date
2024-02-01Referencia bibliográfica
C. Fian, J. A. Muñoz, R. Forés-Toribio, E. Mediavilla, J. Jiménez-Vicente, D. Chelouche, S. Kaspi and G. T. Richards. Probing the structure of the lensed quasar SDSS J1004+4112 through microlensing analysis of spectroscopic data. A&A, 682 (2024) A57 DOI: https://doi.org/10.1051/0004-6361/202347382
Sponsorship
Grants PID2020-118687GB-C31, PID2020-118687GB-C32, and PID2020-118687GB-C33, financed by the Spanish Ministerio de Ciencia e Innovación through MCIN/AEI/10.13039/501100011033; Generalitat Valenciana with the project of excellence Prometeo/2020/085; Projects FQM-108, P20_00334, and A-FQM-510-UGR20/FEDER, financed by Junta de Andalucía; The DFG grant HA3555-14/1 to University of Haifa and Tel Aviv University; The Israeli Science Foundation grant no. 2398/19Abstract
Aims. We aim to reveal the sizes of the continuum and broad emission line (BEL) emitting regions in the gravitationally lensed
quasar SDSS J1004+4112 by analyzing the unique signatures of microlensing in this system. Through a comprehensive analysis of
20 spectroscopic observations acquired between 2003 and 2018, we studied the striking deformations of various BEL profiles and
determined the sizes of their respective emitting regions.
Methods. Our approach involves a detailed analysis of the magnitude di erences in the BEL wings and their adjacent continua, and
the implementation of a statistical model to quantify the distribution and impact of microlensing magnifications. To ensure a reliable
baseline for no microlensing, we used the emission line cores as a reference. We then applied a Bayesian estimate to derive the size
lower limits of the Lyα, Si IV, CIV, C III], and MgII emitting regions, as well as the sizes of the underlying continuum-emitting
sources.
Results. We analyzed the outstanding microlensing-induced distortions in the line profiles of various BELs in the quasar image A,
characterized by a prominent magnification of the blue part and a strong demagnification of the red part. From the statistics of
microlensing magnifications and using Bayesian methods, we estimate the lower limit to the overall size of the regions emitting the
BELs to be a few light-days across, which is significantly smaller than in typically lensed quasars. The asymmetric deformations in
the BELs indicate that the broad-line region is generally not spherically symmetric, and is likely confined to a plane and following
the motions of the accretion disk. Additionally, the inferred continuum-emitting region sizes are larger than predictions based on
standard thin-disk theory by a factor of ~3:6 on average. The size-wavelength relation is consistent with that of a geometrically thin
and optically thick accretion disk.