Probing the Broad-Line Region and the Accretion Disk in the Lensed Quasars HE 0435-1223, WFI 2033-4723, and HE 2149-2745 Using Gravitational Microlensing

Abstract

-2 -We use single-epoch spectroscopy of three gravitationally lensed quasars, HE0435-1223, WFI2033-4723, and HE2149-2745, to study their inner structure (BLR and continuum source). We detect microlensing-induced magnification in the wings of the broad emission lines of two of the systems (HE0435-1223 and WFI2033-4723). In the case of WFI2033-4723, microlensing affects two "bumps" in the spectra which are almost symmetrically arranged on the blue (coincident with an Al III emission line) and red wings of C III]. These match the typical double-peaked profile that follows from disk kinematics. The presence of microlensing in the wings of the emission lines indicates the existence of two different regions in the BLR: a relatively small one with kinematics possibly related to an accretion disk, and another one that is substantially more extended and insensitive to microlensing. There is good agreement between the estimated size of the region affected by microlensing in the emission lines, r s = 10 M/M ⊙ light-days. The estimates of p, the exponent of the size vs. wavelength (r s ∝ λ p ), are 1.2 ± 0.6, 0.8 ± 0.2, and 0.4 ± 0.3 for HE0435-1223, WFI2033-4723, and HE2149-2745, respectively. In conclusion, the continuum microlensing amplitude in the three quasars and chromaticity in WFI2033-4723 and HE2149-2745 are below expectations for the thin disk model. The disks are larger and their temperature gradients are flatter than predicted by this model.

Accretion Disk Size Measurement and Time Delays in the Lensed Quasar WFI 2033–4723

“…For the black hole mass (M BH ), we use the result from Sluse et al (2012) The expectation value for the scale radius at λ rest = 2681Å without the prior on the mass of microlenses is log (r s /cm)[cos(i)/0.5] 1/2 = 15.86 +0.25 −0.27 . This is fully consistent with the results of Motta et al (2017), who estimate a scale radius r s ≈ 1.6 +0.5 −0.4 × 10 16 cm at λ rest = 1310Å using single-epoch spectroscopy, which, when scaled to 2481Å assuming r s ∝ λ 4/3 is log(r s /cm) = 15.8 +0.2 −0.1 . The Motta et al (2017) result is strongly dependent upon priors, especially the assumption of a median microlens mass M * /M = 0.3, nevertheless, the independence of the techniques provides robust support for our result.…”

“…Recently, however, Giannini et al (2017) made a robust detection of microlensing in their 4-season monitoring campaign using the 1.54m Danish telescope at La Silla, a result which we independently corroborated in this investigation. Most recently, Motta et al (2017) used the single-epoch chromatic microlensing technique to make estimates of the size of the central engine and broad line region in WFI2033.…”

Microlensing Analysis for the Gravitational Lens Systems SDSS0924+0219, Q1355-2257, and SDSS1029+2623

“…To distinguish between microlensing, chromatic microlensing and extinction we compare the magnitude difference in the continuum under the emission lines with the magnitude difference in the emission line cores, ∆m = (m B − m A ) cont − (m B − m A ) core (e.g., see Mediavilla et al 2009Mediavilla et al , 2011Rojas et al 2014;Motta et al 2017). We perform this analysis using a set of python packages 4 .…”

“…If we find differences between the profiles, we integrate the line using windows of 25-30 Å (in the rest frame) for both the red and blue wings. The magnitude difference between the lines is used to estimate the size of the BLR (Guerras et al 2013;Motta et al 2017).…”

Quasar lenses and pairs in the VST-ATLAS and Gaia

“…Through the lensing effect, one can ob-tain 1 : (i) a purely gravitational measurement of the properties of the deflector(s), including their invisible components like dark matter halos and individual stars (e.g. Oguri et al 2014); (ii) a magnified view of the background quasar, accretion disk, and host galaxy (Peng et al 2006;Sluse et al 2015;Motta et al 2017;Ding et al 2017); (iii) information about distances and thus cosmological parameters (Refsdal 1964;Cárdenas et al 2013;Treu & Marshall 2016;Suyu et al 2017). Spectroscopy of close sightlines, be they to multiple quasar images or to pairs of physically distinct quasars, is a probe of: (i) kinematics of the cosmic web at high redshift (Rauch et al 2005); (ii) small-scale structure of Lyα absorbers (Smette et al 1992;Dinshaw et al 1998;Rorai et al 2017); (iii) physical conditions of the cool ISM/CGM of galaxies and quasars (Farina et al 2014;Zahedy et al 2016).…”