[Previous] | [Session 142] | [Next]
P Jamkhedkar, H Zhan, L Fang (University of Arizona)
Analysing a Ly\alpha transmitted flux using a space scale decomposition, we found that the transmitted flux field is highly intermittent. Intermittency refers to strong field fluctuations (spikes) localized in small regions with almost no fluctuation between spikes. We found two strong indications of intermittency on scales from 1 h-1 Mpc down to 10h-1 kpc : 1) the probability distribution function of local flux fluctuations has a significantly long tail on small scales, and 2) the spatial distribution of the local power spectrum shows prominent spiky features on small scales. Intermittency can be used to study the nonlinear regime of structure formation. We have employed it to test the validity of the hierarchical clustering model. We have also used the observed intermittent features to discriminate between simulations using different cosmologies. We have found that intermittency induces large uncertainty in the power spectrum measurement. Thus the power spectrum is not effective to describe an intermittent field. We develop new statistical tools like structure functions and the intermittent exponent to describe an intermittent field.