Related papers: A Time Delay for the Largest Gravitationally Lense…
We present 279 epochs of optical monitoring data spanning 5.4 years from 2007 January to 2012 June for the largest image separation (22.6 arcsec) gravitationally lensed quasar, SDSS J1029+2623. We find that image A leads the images B and C…
We present new light curves for the four bright images of the five image cluster-lensed quasar gravitational lens system SDSS~J1004+4112. The light curves span 14.5 yr and allow measurement of the time delay between the trailing bright…
We report first results from an ongoing monitoring campaign to measure time delays between the six images of the quasar SDSS\,J2222$+$2745, gravitationally lensed by a galaxy cluster. The time delay between A and B, the two most highly…
We have built a new model for the lens system SDSS J1004+4112 including the recently measured time delay of the fourth quasar image. This time delay has a strong influence on the inner mass distribution of the lensing cluster ($\rho \propto…
We present 107 new epochs of optical monitoring data for the four brightest images of the gravitational lens SDSS J1004+4112 observed between October 2006 and June 2007. Combining this data with the previously obtained light curves, we…
We present optical lightcurves of the gravitationally lensed components A (=A1+A2+A3) and B of the quadruple quasar RX J0911.4+0551 (z = 2.80). The observations were primarily obtained at the Nordic Optical Telescope between 1997 March and…
We present seven epochs of spectroscopy on the quadruply imaged quasar SDSS J1004+4112, spanning observed-frame time delays from 1 to 322 days. The spectra reveal differences in the emission lines between the lensed images. Specifically,…
We investigate the dependence of the time delays for the large-separation gravitationally lensed quasar SDSS J1004+4112 on the inner mass profile of the lensing cluster. Adopting the mass model whose innermost density profile is…
We present a free-form lens model for the multiply lensed quasar in the galaxy cluster SDSS J$1004+4112$. Our lens model makes minimal assumptions about the distribution of mass in the lens plane. We pay particular attention to the model…
This paper presents optical R-band light curves and the time delay of the doubly imaged gravitationally lensed quasar SDSS J1001+5027 at a redshift of 1.838. We have observed this target for more than six years, between March 2005 and July…
We present eight monitoring seasons of the four brightest images of the gravitational lens SDSS J1004+4112 observed between December 2003 and October 2010. Using measured time delays for the images A, B and C and the model predicted time…
We have measured the time delay between the two images of the gravitationally lensed quasar HE1104-1805 by combining observations made with the Wise Observatory 1m telescope and published observations of this system by Schechter et al.,…
Aims: Our aim is to measure the time delay between the two gravitationally lensed images of the z = 1.547 quasar SDSS J1650+4251, in order to estimate the Hubble constant H_0. Methods: Our measurement is based on R-band light curves with 57…
We present an $r$--band photometric monitoring of the two images A and B of the gravitationally lensed quasar SDSS J1442+4055 using the Liverpool Telescope (LT). From the LT light curves between 2015 December and 2018 August, we derive at…
We spectroscopically re-observed the gravitational lens system SDSS J1339+1310 using OSIRIS on the GTC. We also monitored the $r$-band variability of the two quasar images (A and B) with the LT over 143 epochs in the period 2009$-$2016.…
SDSS J2222+2745 is a galaxy cluster at z=0.49, strongly lensing a quasar at z=2.805 into six widely separated images. In recent HST imaging of the field, we identify additional multiply lensed galaxies, and confirm the sixth quasar image…
We study the recently discovered gravitational lens SDSS J1004+4112, the first quasar lensed by a cluster of galaxies. It consists of four images with a maximum separation of 14.62''. The system has been confirmed as a lensed quasar at…
SDSS J1004+4112 is a well studied gravitational lens with a recently measured time delay between its first and fourth arriving quasar images. Using this new constraint, we present updated free-form lens reconstructions using the lens…
We present results from a seven-season (2018-2024) monitoring campaign of the gravitationally lensed quasar system PS J2305+3714 using the 1.5-m Maidanak Telescope in the optical R-band. From these data, the amplitude of possible…
We analyse new optical observations of the gravitational lens system SDSS J1515+1511. These include a 2.6-year photometric monitoring with the Liverpool Telescope (LT) in the $r$ band, as well as a spectroscopic follow-up with the LT and…