CLASS B1152+199 and B1359+154: Two New Gravitational Lens Systems Discovered in the Cosmic Lens All-Sky Survey

The third phase of the Cosmic Lens All-Sky Survey (CLASS) has recently beencompleted, bringing the total number of sources imaged to over 15000 in theCLASS and JVAS combined survey. In the VLA observations carried out in Marchand April of 1998, two new candidate lensed systems were discovered: CLASSB1152+199 and B1359+154. B1152+199 is a 1.6 arcsecond double, with a backgroundquasar at z=1.019 lensed by a foreground galaxy at z=0.439. The relatively flatradio spectra of the lensed images, combined with a previous ROSAT detection ofthe source, make B1152+199 a strong candidate for time delay studies at bothradio and X-ray wavelengths. B1359+154 is a quadruply lensed quasar at z=3.235,with a maximum image separation of 1.7 arcseconds. As yet, the redshift of thelensing object in this system is undetermined. The steep spectral index of thesource suggests that B1359+154 will not exhibit strong variability, and istherefore unlikely to be useful for determining the Hubble constant frommeasured time delays.Comment: accepted for publication in The Astronomical Journa