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The size of the dust torus in active galactic nuclei (AGNs) and their high-luminosity counterparts, quasars, can be inferred from the time delay between UV/optical accretion disk continuum variability and the response in the mid-infrared (MIR) torus emission. This dust reverberation mapping (RM) technique has been successfully applied to ∼70 z ≲ 0.3 AGNs and quasars. Here we present first results of our dust RM program for distant quasars covered in the Sloan Digital Sky Survey Stripe 82 region combining ∼20 yr ground-based optical light curves with 10 yr MIR light curves from the WISE satellite. We measure a high-fidelity lag between W1 band (3.4 μm) and g band for 587 quasars over 0.3 ≲ z ≲ 2 () and two orders of magnitude in quasar luminosity. They tightly follow (intrinsic scatter ∼0.17 dex in lag) the IR lag–luminosity relation observed for z < 0.3 AGNs, revealing a remarkable size–luminosity relation for the dust torus over more than four decades in AGN luminosity, with little dependence on additional quasar properties such as Eddington ratio and variability amplitude. This study motivates further investigations in the utility of dust RM for cosmology and strongly endorses a compelling science case for the combined 10 yr Vera C. Rubin Observatory Legacy Survey of Space and Time (optical) and 5 yr Nancy Grace Roman Space Telescope 2 μm light curves in a deep survey for low-redshift AGN dust RM with much lower luminosities and shorter, measurable IR lags. The compiled optical and MIR light curves for 7384 quasars in our parent sample are made public with this work. [ABSTRACT FROM AUTHOR]

We describe 10 strong lensing galaxy clusters of redshift 0.26 ⩽ z ⩽ 0.56 that were found in the Sloan Digital Sky Survey. We present measurements of richness (N200), mass (M200), and velocity dispersion for the clusters. We find that in order to use the mass-richness relation from Johnston et al., which was established at mean redshift of 0.25, it is necessary to scale measured richness values up by 1.47. Using this scaling, we find richness values for these clusters to be in the range of 22 ⩽ N200 ⩽ 317 and mass values to be in the range of 1 × 1014h–1M☼ ⩽ M200 ⩽ 30 × 1014h–1M☼. We also present measurements of Einstein radius, mass, and velocity dispersion for the lensing systems. The Einstein radii (θE) are all relatively small, with 5.″4 ⩽ θE ⩽ 13″. Finally, we consider if there is evidence that our clusters are more concentrated than ΛCDM would predict. We find that six of our clusters do not show evidence of overconcentration, while four of our clusters do. We note a correlation between overconcentration and mass, as the four clusters showing evidence of overconcentration are all lower-mass clusters. For the four lowest mass clusters the average value of the concentration parameter c200 is 11.6, while for the six higher-mass clusters the average value of c200 is 4.4. ΛCDM would place c200 between 3.4 and 5.7. [ABSTRACT FROM AUTHOR]