Subaru Telescope adaptive optics observations of gravitationally lensed quasars in the Sloan Digital Sky Survey

Abstract

We present the results of an imaging observation campaign conducted with the Subaru Telescope adaptive optics system (IRCS+AO188) on 28 gravitationally lensed quasars and candidates (23 doubles, 1 quad, 1 possible triple and 3 candidates) from the SDSS Quasar Lens Search. We develop a novel modelling technique that fits analytical and hybrid point spread functions (PSFs), while simultaneously measuring the relative astrometry, photometry, as well as the lens galaxy morphology. We account for systematics by simulating the observed systems using separately observed PSF stars. The measured relative astrometry is comparable with that typically achieved with the Hubble Space Telescope, even after marginalizing over the PSF uncertainty. We model for the first time the quasar host galaxies in 5 systems, without a-priory knowledge of the PSF, and show that their luminosities follow the known correlation with the mass of the supermassive black hole. For each system, we obtain mass models far more accurate than those previously published from low-resolution data, and we show that in our sample of lensing galaxies the observed light profile is more elliptical than the mass, for ellipticity 0.25. We also identify eight doubles for which the sources of external and internal shear are more reliably separated, and should therefore be prioritized in monitoring campaigns aimed at measuring time-delays in order to infer the Hubble constant.

The Boss Emission-Line Lens Survey. Iv. Smooth Lens Models for the Bells Gallery Sample*

“…However, this can lead to two problems: (1) automatic adjustments are not possible if the lensing and junk features are masked inappropriately, which can affect the foreground-light fitting; (2) the pixel count errors estimated for the full data might not be appropriate for the foreground-subtracted residual, and hence bias the fitting process. Therefore, we perform the foreground-light subtraction jointly with the lens modeling, as done in Shu et al (2016a) and Rusu et al (2016).…”

H0LiCOW. VI. Testing the fidelity of lensed quasar host galaxy reconstruction

“…This iterative process will be used when analyzing the real lens systems, and the residual uncertainties taken into account when measuring the host galaxy luminosity. An alternative scheme for modelling the PSF in ground based data is described by Rusu et al (2016b) and applied to adaptive optics observations of gravitationally lensed AGNs from SDSS Quasar Lens Search (SQLS).…”

Time delay cosmography

“…Planned surveys like Euclid and WFIRST will be excellent at discovering new lenses, but probably will have insufficient depth and resolution except for the brightest systems. Therefore targeted follow-up will be required, achievable either with JWST from space, or with improved adaptive optics systems on 8-10m class ground-based telescopes (Marshall et al, 2007;Chen et al, 2016;Rusu et al, 2016). Integral field spectrographs on giant segmented mirror telescopes will be the ideal complement to LSST, by providing the necessary high resolution imaging and spectroscopy with relatively short exposure times (e.g.…”