Volume 88, Number 5, December 2009
|Number of page(s)||6|
|Section||Geophysics, Astronomy and Astrophysics|
|Published online||11 December 2009|
Galaxy distribution and extreme-value statistics
Program for Evolutionary Dynamics, Harvard University - Cambridge, MA 02138, USA
2 Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi - Piazzale del Viminale 1, 00184 Rome, Italy, EU
3 Istituto dei Sistemi Complessi CNR - Via dei Taurini 19, 00185 Rome, Italy, EU
4 Institute of Astronomy, St. Petersburg State University - Staryj Peterhoff, 198504, St. Petersburg, Russia
Accepted: 12 November 2009
We consider the conditional galaxy density around each galaxy, and study its fluctuations in the newest samples of the Sloan Digital Sky Survey Data Release 7. Over a large range of scales, both the average conditional density and its variance show a non-trivial scaling behavior, which resembles criticality. The density depends, for 10 ≤ r ≤ 80 Mpc/h, only weakly (logarithmically) on the system size. Correspondingly, we find that the density fluctuations follow the Gumbel distribution of extreme-value statistics. This distribution is clearly distinguishable from a Gaussian distribution, which would arise for a homogeneous spatial galaxy configuration. We also point out similarities between the galaxy distribution and critical systems of statistical physics.
PACS: 98.80.-k – Cosmology / 05.40.-a – Fluctuations phenomena, random processes, noise, and Brownian motion / 02.50.-r – Probability theory, stochastic processes, and statistics
© EPLA, 2009
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