Fractal dimensions in the large-scale distribution of IRAS galaxies

Fractal dimensions of the volume-limited subsamples with various IR luminosities sorted out from samples given by the IRAS galaxy redshift surveys in fields F15 and NGW are calculated. The distribution of IRAS galaxies has multilevel fractal structure. That is, the distribution has fractal structure with a definite fractal dimension D only in certain scale range, and as the scale increases to a certain turning scale rc, the distribution transits to another fractal structure with different D. The fractal dimensions on levels with larger scales are generally larger than that on the levels with smaller scales. Clustering of galaxies is the dominant character on rather small scales, but on larger scales it becomes distribution with voids.