CLASS

The Cosmic Lens All-Sky Survey (CLASS) is a search for gravitational lenses among flat-spectrum radio sources with the VLA. The survey sample contains nearly 14,000 flat spectrum sources. Sixteen new gravitational lenses have been found in CLASS. CLASS builds on the success of the Jodrell-VLA Astrometric Survey (JVAS), which found five new gravitational lenses from a sample of brighter flat-spectrum radio sources.

The parent sample for CLASS is the GB6 NRAO 5 GHz catalogue (Gregory and Condon). Flat spectrum sources were selected from this catalogue by comparing the 5 GHz flux density with that in the 1.4 GHz NRAO VLA Sky Survey (NVSS). An additional sample of flat spectrum sources was selected by using the 325 MHz Westerbork Northern Sky Survey (WENSS) as the low frequency point.

Go to the NRAO CLASS Page for a more in-depth description of the CLASS Survey.

Also check out the CERES home page for research coming out of the CLASS and JVAS surveys. and the CASTLES home page for a compilation of lenses.

More about CLASS:

Return to Chris's Home Page.

page by Chris Fassnacht, fassnacht @ physics.ucdavis.edu.