The large scale inhomogeneity of the galaxy distribution and the absence of Baryonic Acoustic Oscillations - Francesco Sylos Labini - Roma

jeudi 2 juil. 2009, 11:00 → 12:00 Europe/Paris

Salle Grossetete (LPNHE)

By studying  the probability density function of conditional fluctuations  in the newest galaxy samples of the Sloan Digitial Sky Survey and of Two degree Field Galaxy  Redshift Survey, we show that large scale structures are quite typical and correspond to large fluctuations  in the density field. We test two basic hypotheses of the standard statistical analysis, namely that of self-averaging of fluctuations and of spatial homogeneity. We find that the fluctuations are not in fact self-averaging and the galaxy distribution is inhomogeneous up to scales of the order of 100 Mpc/h In addition we do not find any statistical evidence for the  scale corresponding to the Baryonic Acoustic Oscillations, and we measure positive two-point correlations extending to scales larger than what is predicted by the LCDM model, i.e. ~ 120 Mpc/h. Finally we discuss that standard theoretical models of  structure formation are unable to explain the existence of the  large fluctuations in the galaxy density field detected in these  samples.

Slides FSL_lpnhe.pdf