Evidence for Gaussian Initial Fluctuations from the 1.2 Jy Iras Survey

This figure "fig2-1.png" is available in "png"" format from: This figure "fig3-1.png" is available in "png"" format from: This figure "fig4-1.png" is available in "png"" format from: This figure "fig5-1.png" is available in "png"" format from: This figure "fig6-1.png" is available in "png"" format from: { 15 { FIGURE CAPTIONS Fig. 1.| The PDF of the density eld from the 1.2 Jy IRAS galaxy catalog (circles connected by a solid line) compared with a Gaussian (dotted line) and with the PDF of a model, computed from a series of 20 density elds of Gaussian CDM Monte-Carlo simulations (triangles). The error bars are the standard deviations over the simulations and measure both the eeect of the limited volume sampled by IRAS and the eeect of shot noise in the IRAS sampling. Note, however, that the data points are correlated due to smoothing. Fig. 2.| The IPDF recovered from the 1.2 Jy IRAS catalog, compared to the IPDF recovered from the Gaussian CDM model, for diierent values of b. The notation is as in Fig 1. ABSTRACT We recover the one-point probability distribution function of the initial density uctuations (IPDF) from the quasi-linear galaxy density eld of the 1.2 Jy IRAS redshift survey smoothed by 10 h 1 Mpc. The recovery, using the laminar, Eulerian, Zel'dovich approximation of Nusser and Dekel, is independent of and is relatively insensitive to linear galaxy biasing in the range 0:5 b 2. Errors due to discrete sampling, the limited survey volume, and the method of recovering the IPDF are evaluated by comparing the IPDF determined from the IRAS data with Monte-Carlo IRAS-like catalogs \observed" from N-body simulations of CDM models with Gaussian initial conditions. Eight sensitive statistical tests used in this comparison nd the IRAS IPDF to be consistent with Gaussian. We provide observational constraints on possible deviations from Gaussianity, which should be obeyed by any theoretical model.