Figure 1: The VVDS redshift sampling rate in the four-passes VVDS-02h-4 region is plotted versus the observed apparent magnitude in the I-band. The mean redshift sampling rate is 0.3. | |
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Figure 2: The real- and redshift-space rms fluctuations of the flux-limited VVDS sample recovered using Eq. (13) and the results of the correlation function analysis presented in Paper III are plotted at six different redshifts in the interval 0.4<z<1.7. | |
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Figure 3: 3D density field traced by the galaxy distribution in the VVDS-02h Field ( left, 1641 galaxies), in the flux-limited () GALICS simulation ( right, 9450 galaxies), and in the flux-limited GALICS sample after applying the VVDS target selection criteria ( center, 1656 galaxies). Data span the redshift interval [0.8, 1.1]. In each cone, the galaxy distribution is continuously smoothed using a TH window function with R=5 h^{-1}Mpc which nearly corresponds to the mean inter-particle separation in this same redshift interval. The cone metric was computed assuming a CDM cosmology and the correct axis ratio between transversal and radial dimensions has been preserved. The cones have approximate transverse dimensions of 28 h^{-1}Mpcat z=1 and extend over 527 h^{-1}Mpc. | |
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Figure 4: Tests of the PDF reconstruction scheme using the mocks VVDS samples extracted from GALICS. The differential ( ) probability distribution functions of for the "observed'' s-sample (dotted line, shadowed histogram), and for the parent p-sample (solid-line). Note that the plotted histograms actually corresponds to since the binning is done in . The logarithmic PDFs are computed for density fields smoothed using TH filters of different sizes (indicated on the top of each panel). | |
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Figure 5: The cumulative distribution function of density contrasts , on scales R=5 h^{-1}Mpc,as recovered in different redshift intervals for the s-sample (dotted line), and for the parent p-sample (solid-line). The flattened pedestal at the low-density end of the cumulative distribution is due to low density regions in the p-sample that are spuriously sampled as empty regions ( ) in the s-sample. | |
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Figure 6: Top: the PDF per units of galaxy overdensities ( ) is plotted for the volume limited VVDS sample ( ) at three different redshifts. The PDFs are computed for density fields recovered using TH filters of size 8 and 10 h^{-1}Mpc. Bottom: the corresponding cumulative distributions. Errorbars (which, for clarity, are plotted only for the redshift bin 1.25<z<1.5) represent the Poissonian uncertainties. The flattened pedestal at the low-density end of the cumulative distribution is contributed by empty regions ( ). | |
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Figure 7: Redshift evolution of the standard deviation ( upper panel) and of the skewness ( lower panel) of the galaxy PDF on a scale R=8 h^{-1}Mpc for galaxies brighter than . The corresponding local values, estimated on the same scale by Croton et al. (2004) using a subsample of the 2dFGRS having nearly the same median absolute luminosity of our sample, are represented with triangles. Error bars represent 1 errors, and, in the case of VVDS measurements, include the contribution from cosmic variance. The errorbar on of the 2dFGRS is smaller than the symbol size. | |
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Figure 8: Redshift scaling of the rms mass fluctuations in sphere of 8 h^{-1}Mpcradius. Diamonds represent as computed from the CDM Hubble volume simulation in real comoving space (x-space), while triangles represent the corresponding values recovered in the redshift perturbed comoving coordinates (y-space). The solid line is the analytical prediction for the scaling of in the y-space obtained using Eq. (30), while the dotted line represents the x-space evolution predicted in real space. In both cases the power spectrum of perturbations is the same and has been normalized in order to match the simulation specifications ( ). | |
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Figure 9: One-point PDFs of dark matter fluctuations (shaded area) computed using the Hubble volume CDM cosmological simulation in 4 different redshift ranges over a volume which mimics the geometry of the VVDS sample. The mass PDF has been recovered in the redshift comoving space by smoothing the mass-particle distribution with a TH window of size R=8 h^{-1}Mpc.Note that the plotted histogram actually corresponds to because the binning (d ) is done in . The dotted line represents the lognormal approximation derived in the real comoving space using Eq. (16). The solid curve represents the lognormal approximation computed adopting the variance parameter (shown in the inset) theoretically inferred using Eq. (30), which models peculiar velocity distortions as a function of redshift. | |
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Figure 10: The simulated biasing function (solid-line) at different cosmic epochs, between the density field traced by the s-sample (GALICS data simulating the VVDS sample, see Pollo et al. (2005) and Sect. 4.1) and the density field traced by the p-sample (GALICS data simulating the real underlying distribution of galaxies). represent the linear bias parameter evaluated from the nonlinear biasing function using the estimator given in Eq. (32). The dashed line is drawn at and represents the no bias case. The central cross is for reference and represents the case. The r parameter measures the deviations from the linearity. The galaxy overdensities are reconstructed using a TH window of sizes R=5 h^{-1}Mpc( upper panel) and R=8 h^{-1}Mpc( lower panel). The shadowed area represents 1 errors in the derived biasing function. | |
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Figure 11: The observed biasing function (solid-line) recovered for the density field smoothed on scales R=8 h^{-1}Mpc( upper panel) and 10 h^{-1}Mpc( lower panel) and for different redshift bins (from left to right) in the volume-limited VVDS sample ( ). The dotted line represents the linear biasing model while the no-bias case ( ) is shown with a dashed line. The central cross is for reference and represents the case. The shaded area represents errors in the derived biasing function. Errors take into account the noise in the observed galaxy PDF ( ), but do not include uncertainties due to cosmic variance. | |
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Figure 12: The biasing function (solid-line) on scales R=8 h^{-1}Mpcand in the redshift interval 0.7<z<0.9 computed for different luminosity classes. Symbols are as in Fig. 11. | |
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Figure 13: The redshift evolution of the linear biasing parameter for the volume-limited ( ) subsample (filled squares) is compared to the evolution of the biasing parameter for the whole flux-limited VVDS-02h sample (empty squares). Since there is no significant evidence of scale dependence in the biasing relation, we have averaged the biasing parameters measured on 5, 8, and 10 h^{-1}Mpcscales in order to cover the full redshift baseline 0.4<z<1.5. For clarity, only the errorbars corresponding to the volume-limited sample are shown. The triangle represents the bias inferred for 2dFGRS galaxies having median ( i.e. the median luminosity of the volume-limited VVDS sample) as explained in the text. | |
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Figure 14: Comparison between the galaxy linear bias parameter measured in the redshift interval 0.4<z<0.9 for 3 different luminosity classes (squares) and the corresponding local estimates provided by the 2dFGRS (triangles). Points with increasing sizes correspond to three different volume-limited VVDS subsamples, i.e and <-20, respectively. For clarity, squares with increasing size have been progressively displaced rightward to avoid crowding. The z0 measurements have been interpolated by using the formula describing the luminosity dependence of the 2dFGRS bias parameter (Norberg et al. 2001), the bias parameter for the 2dFGRS L^{*} sample ( i.e. b_{*}=0.92 (Verde et al. 2002)) and the median luminosity of the three VVDS subsamples (L/L^{*}=0.52,0.82,2.0 respectively). | |
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Figure 15: Upper panel: redshift evolution of the galaxy bias on a scale R=8 h^{-1}Mpcfor the red (squares) and blue (triangles) galaxies in the volume limited samples. For clarity, the triangles have been slightly displaced rightward to avoid crowding. Black diamonds represent the global bias for galaxies brighter than . Lower panel: the relative bias between the red and blue population ( ) is shown as a function of redshift.The filled and shaded areas represents the 1 confidence region of the value for the relative bias derived by Wilmer et al. (1998) and Wild et al. (2005) respectively. The diamond represents the relative bias measured by Coil et al. (2004) in the redshift interval (0.7-1.35). | |
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Figure 16: The redshift evolution of the linear biasing parameter for the volume-limited ( ) sample (see Fig. 13) is compared to various theoretical models of biasing evolution. The dotted line indicates the conserving model normalized at b_{f}(z=1.4)=1.28, the solid and dashed lines represent the star forming and merging models with the mass thresholds set at and respectively. | |
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