Fig. 5.

Same as Fig. 4 but for various size distribution functions with the W+06 yield model: (a) graphite and (b) silicate. The thick solid lines are the MRN case. The short-dashed lines are the size distribution expected from the grain formation model in supernova ejecta by Nozawa et al. (2003). The dotted lines are the size distribution expected after the grain destruction by the reverse shock in the supernova remnant by Nozawa et al. (2007). The triple-dot-dashed lines are the MRN but only of a size larger than 0.1 μm because of a filtering effect in the transfer of grains from galaxies to the IGM, as suggested by Bianchi and Ferrara (2005). The thin solid lines are the MRN but only size smaller than 250 Å as a comparison. The dashed and dot-dashed lines are HI and HeII heating rates.