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Published June 1999 | Published + Accepted Version
Journal Article Open

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 been completed, bringing the total number of sources imaged to over 15,000 in the CLASS and Jodrell-VLA Astrometric Survey combined survey. In the VLA observations carried out in 1998 March and April, two new candidate lensed systems were discovered: CLASS B1152+199 and B1359+154. B1152+199 is a 1."6 double, with a background quasar at z = 1.019 lensed by a foreground galaxy at z = 0.439. The relatively flat radio spectra of the lensed images (α^(14.94)_(-8.46) = -0.32), combined with a previous ROSATdetection of the source, make B1152+199 a strong candidate for time delay studies at both radio and X-ray wavelengths. B1359+154 is a quadruply lensed quasar at z = 3.235, with a maximum image separation of 1."7. As yet, the redshift of the lensing object in this system is undetermined. The steep spectral index of the source (α^(14.94)_(-8.46) = -0.9) suggests that B1359+154 will not exhibit strong variability and is therefore unlikely to be useful for determining H_0 from measured time delays.

Additional Information

© 1999 The American Astronomical Society. Received 1998 November 17; accepted 1999 February 19. S. T. M. is supported by a Alfred P. Sloan Fellowship. The CLASS survey at Caltech is supported by NSF grants AST-9420018 and AST-9117100. CLASS at Jodrell Bank, UK, is supported by the European Commission, TMR Program, Research Network Contract ERBFMRXCT96-0034 "CERES." We thank the staff of the VLA, Palomar, and Keck observatories for their assistance during our observing runs. This research has made use of the NASA/ IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The NASA ADS and ADC were also used during the course of the work reported here. We also thank Brian Mason for computing the ROSAT X-ray flux for B1152+199.

Attached Files

Published - Myers_1999_AJ_117_2565.pdf

Accepted Version - 9905043.pdf


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