Gravitational lensing statistics with extragalactic surveys - II. Analysisof the Jodrell Bank-VLA Astrometric Survey

We present constraints on the cosmological constant lambda(0) from gravitat ional lensing statistics of the Jodrell Bank-VLA Astrometric Survey (JVAS). Although this is the largest gravitational lens survey which has been anal ysed, cosmological constraints are only comparable to those from optical su rveys. This is due to the fact that the median source redshifts of JVAS are lower, which leads to both relatively fewer lenses in the survey and a wea ker dependence on the cosmological parameters. Although more approximations have to be made than is the case for optical surveys, the consistency of t he results with those from optical gravitational lens surveys and other cos mological tests indicate that this is not a major source of uncertainty in the results. However, joint constraints from a combination of radio and opt ical data are much tighter. Thus, a similar analysis of the much larger Cos mic Lens All-Sky Survey should provide even tighter constraints on the cosm ological constant, especially when combined with data from optical lens sur veys. At 95% confidence, our lower and upper limits on lambda(0) - Omega(0) , using the JVAS lensing statistics information alone, are respectively -2. 69 and 0.68. For a flat universe, these correspond to lower and upper limit s on lambda(0) of respectively -0.85 and 0.84. Using the combination of JVA S lensing statistics and lensing statistics from the literature as discusse d in Quast & Helbig (1999) the corresponding lambda(0) - Omega(0) values ar e -1.78 and 0.27. For a hat universe, these correspond to lower and upper l imits on lambda(0) of respectively -0.39 and 0.64.