Strong Chromatic Microlensing in He0047–1756 and Sdss1155+6346

We use spectra of the double lensed quasars HE0047-1756 and SDSS1155+6346 to study their unresolved structure through the impact of microlensing. There is no significant evidence of microlensing in the emission line profiles except for the Ly line of SDSS1155+6346, which shows strong differences in the shapes for images A and B. However, the continuum of the B image spectrum in SDSS1155+6346 is strongly contaminated by the lens galaxy and these differences should be considered with caution. Using the flux ratios of the emission lines for image pairs as a baseline to remove macro-magnification and extinction, we have detected strong chromatic microlensing in the continuum measured by CASTLES (http: //www. cfa. harvard. edu/castles/), in both lens systems, with amplitudes 0. 09 (16000) | m | 0. 8 (5439) for HE0047-1756, and 0. 2 (16000) | m | 0. 8 (5439) for SDSS1155+6346. Using magnification maps to simulate microlensing, and modeling the accretion disk as a Gaussian source (I exp (-R^2/2r²ₛ) ) of size rₒ ^p we find, rₒ = 2. 5-₁. ₄^+3. 0 M/0. 3M_ light days and p = 2. 3 0. 8, at the rest frame for = 2045, for HE0047-1756 (log prior), and rₒ = 5. 5-₃. ₃^+8. 2 M/0. 3M_ light days and p = 1. 5 0. 6 at the rest frame of = 1398, for SDSS1155+6346 (log prior). Contrary to other studied lens systems, the chromaticity detected in HE0047-1756 and SDSS1155+6346 is large enough to fulfill the thin disk prediction. The inferred sizes, however, are very large compared to the predictions of this model, especially in the case of SDSS1155+6346.