- For Teachers
I have written an abstract. I would be very grateful if you could correct my mistakes.
Today, modern astronomers extensively study about the distribution of the galaxies in the universe. Part of these research includes statistical analysis of the number of the galaxies in cubic cells (cell counts), since working with such a data is easier than raw spatial data with their complex spatial patterns. There exist various models for cell count distribution (Martínez and Saar, 2002). Classical point process statistics would probably suggest negative binomial distribution because of the high degree of clustering of galaxies. This model has also been used by cosmologist(Elizalde and Gaztañaga,1992 and Betancort-Rijo, 2000). Recently, discrete Weibull distribution was fitted to data (Ghorbani
et al., 2006). This approach seems to be appropriate as there are some models for the galaxy clustering process that are based on the fact that the universe is seen by cosmologists as a result of a growth process (Bernard et al., 2004). Furthermore, Since the number of empty cells is significantly greater than others, Zero-Inflated distributions is also suggested as a new alternative. Also, Zero-Inflated weibull and Zero-Inflated Negative Binomial are introduced to fit to data. In this paper, after studying the dispersion of the galaxies in our real studied space, we fit all proposed distributions to data by numerical methods and then the goodness-of-fit of these models have been compared by the Akaike Information Criterion (AIC).