Astronomy & Astrophysics manuscript no. msLPopovic-3rd-rev c ESO 2021 September 1, 2021 Spectroscopy and polarimetry of the gravitationally lensed quasar SDSS J1004+4112 with the 6m SAO RAS telescope L. C.ˇ Popovic´1, V. L. Afanasiev2, A. Moiseev2; 3, A. Smirnova2, S. Simic´4, Dj. Savic´1; 5, E. G. Mediavilla6; 7, and C. Fian6 1 Astronomical Observatory, Volgina 7, 11000 Belgrade, Serbia e-mail:
[email protected] 2 Special Astrophysical Observatory of the Russian AS, Nizhnij Arkhyz, Karachaevo-Cherkesia 369167, Russia 3 Space Research Institute, Russian Academy of Sciences, Profsoyuznaya ul. 84/32, Moscow 117997, Russia 4 Faculty of Sciences, University of Kragujevac, Radoja Domanovica 12, 34000 Kragujevac, Serbia 5 Université de Strasbourg, CNRS, Observatoire Astronomique de Strasbourg, UMR 7550, 11 rue de lUniversit, F-67000 Strasbourg, France 6 Instituto de Astrofísica de Canarias, Vá Láctea S/N, La Laguna 38200, Tenerife, Spain 7 Departamento de Astrofísica, Universidad de la Laguna, La Laguna 38200, Tenerife, Spain Received September 15, 1996; accepted March 16, 1997 ABSTRACT Context. We present new spectroscopic and polarimetric observations of the gravitational lens SDSS J1004+4112 taken with the 6m telescope of the Special Astrophysical Observatory (SAO, Russia). Aims. In order to explain the variability that is observed only in the blue wing of the C IV emission line, corresponding to image A, we analyze the spectroscopy and polarimetry of the four images of the lensed system. Methods. Spectra of the four images were taken in 2007, 2008, and 2018, and polarization was measured in the period 2014-2017. Additionally, we modeled the microlensing effect in the polarized light, assuming that the source of polarization is the equatorial scattering in the inner part of the torus.