Eyal Kazin edited reconstructed_wedges.tex  almost 10 years ago

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To quantify the significance of detection of the anisotropic baryonic feature in the WiggleZ clustering wedges we compare $\chi^2$ results obtained with best fit models using a $\Lambda$CDM-based template to a ``no-wiggle"-based template, i.e, one with full shape and no baryonic feature \cite{Eisenstein_1998} ($\Delta\chi^2\equiv \chi^2_{\rm min \ no-wiggle}-\chi^2_{\rm min \ \Lambda CDM}$). In this procedure, for each model we vary $H r_{\rm s}$ and $D_{\rm A}/r_{\rm s}$ and marginalize over all other shape parameters, as explained in detail in \S 6.1 of \citet{Kazin_2013}. We find that the significance of detection, defined as $\sqrt{\Delta\chi^2}$, for $\Delta z^{\rm Near}$, $\Delta z^{\rm Mid}$ and $\Delta z^{\rm Far}$ to be $1.6, \ 2.7$ and $2.9$, respectively. Applying our pipeline on the WiZCOLA simulations we find our results consistent with expectations.   We now use the baroynic acoustic feature as a standardized sphere to determine $D_{\rm A}/r_{\rm s}$ and $1/H/r_{\rm s}$. To obtain model-independent constraints we focus on the information contained in the peak positions in $\xi_{||, \ \perp}$ and marginalize over the broad shape. This is performed by using a template based on a linear  $\Lambda$CDM based and using template with  slight peak damping as due to coupling of $k-$modes, and described in the rernomalized perturbation theory of \citet{Crocce_2008}. For simplicity we assume reconstruction perfectly corrects for linear anisotropies, by setting all \xi multipoles except for the monopole to be zero. We run MC-Markov chains when fitting the models to the data while varying $D_{\rm A}/r_{\rm s}$ and $1/H/r_{\rm s}$ with flat prior between [0.5,1.5] of their fiducial cosmology values. In addition we vary for each clustering wedge and amplitude parameter and three polynomial terms each, yielding 10 parameters in total (2+2+2X3). In the results presented here we marginalize over these last eight parameters. A full detailed description of the procedure is given in our previous analysis of the SDSS DR9 CMASS galaxies \citet{Kazin_2013} (see \S 5.3). Figures \ref{fig:HDA_z60_epsilon0.15}-\ref{fig:HDA_z26_epsilon0.15} display the obtained posteriors of $cz/H/r_{\rm s}$ and $D_{\rm A}/r_{\rm s}$ marginazlied to 2D and 1D. In the 2D panels the even contour solid red lines are the 68, 95\% confidence level regions, and we add a Gaussian approximation in each panel based on the mode values, the median values of the 68\% CL region widths and the covariance $r$ between the two parameters. It is apparent that the BAO-only analysis of the $\Delta z^{\rm Far}$ and $\Delta z^{\rm Mid}$ samples yield moderate constraints on these parameters and $\Delta z^{\rm Near}$ does not.