Results of optical monitoring of 5 SDSS double QSOs with the Nordic Optical Telescope

We present optical R-band light curves of five SDSS double QSOs ( SDSS J0903+5028, SDSS J1001+5027, SDSS J1206+4332, SDSS J1353+1138, SDSS J1335+0118) obtained from monitoring at the Nordic Optical Telescope ( NOT) between September 2005 and September 2007. We also present analytical and pixelated modeling of the observed systems. For SDSS J1206+4332, we measured the time delay to be Delta tau = 116(-5)(+4) days, which, for a singular isothermal ellipsoid model, corresponds to a Hubble constant of 73(-4)(+3) km s(-1) Mpc(-1). Simultaneous pixelated modeling of five other systems for which a time delay has now been previously measured at the NOT leads to H-0 = 61.5(- 4)(+8) km s(-1) Mpc(-1). Finally, by comparing light curves of the two images of each system, suitably shifted by the predicted or observed time-delays, we found no evidence of microlensing variability over the course of the monitoring period.