Highly colinear radio sources and constraints on gravitational lens space density

Abstract

There are two conclusions to be drawn from this study. First, the intrinsic bending angle distribution of radio sources at high redshifts has a spike at the origin (i.e., some radio sources are just intrinsically very straight). Second, and of relevance to this conference, the lens-induced bending angle distribution also has a spike at the origin. This may be due to two causes. The distribution may simply be narrow, which by reference to the above calculations implies that $\bar \Omega$ must be fairly small. A value of perhaps 0.3 would reduce the significance of these two sources to a reasonable level, ignoring the likelihood of a broad (if spiky) intrinsic distribution. Alternatively, the universe could be clumpy on truly vast scales, so that we are looking at these two sources along lines of sight that are simply deficient in clumped matter. Note that these conclusions get stronger if many sources are intrinsically bent.