The distribution of some intrinsic parameters of head-tail radio sources

The properties of a sample comprising 44 head-tail galaxies for which radio observations have been published are presented. The distributions of the absolute photographic magnitude, the radio power at 610 MHz, and opening-angle of these sources are presented confirming the results of Owen and Rudnick (1976) and Simon (1978) that wide-angle tailed radio sources (WATs) have larger radio and optical power than narrow angle tailed sources (NATs). It is shown that the photographic magnitude, the radio power, and opening angle parameter distributions of NATs, WATs and double radio sources can be described in terms of the independent blob model of Jaffe and Perola (1973). Double radio sources would then need to be surrounded by a medium about 100 times less dense than that in the clusters, producing stopping times longer than the radiative loss times, but the head-tail sources would have much shorter stopping times allowing them to reveal more sensitively the dependence of morphology on galaxy speed and other parameters.