caption: Fraction of AGN in different types of host galaxy as a function of halo mass, from the sample of <PERSON> (2012). See Table 1 for a conversion between halo mass and group size. This shows the same result as seen in Fig. 8 that there is, at best, only a modest environmental dependence for AGN in spiral galaxies, but that there is a very strong decrease in the number of AGN in S0 hosts in dense environments. This shows in addition that the fraction of AGN in elliptical galaxies increases, which are mostly radio sources.