THCA Seminar

報告題目： Single-probe measurements from SDSS-III/BOSS DR11 CMASS and LOWZ anisotropic galaxy clustering 報告人： Dr.Chia-Hsun Chuang (IFT-UAM/CSIS, Spain) 報告時間： Thursday, 13:30, Jan.16,2014 報告地點： Lecture Hall, Third floor, Science Building 摘要： With the very large spectroscopic galaxy survey volume, for the very first time, we could extract cosmological constraints from the quasi-linear scales measurements (i.e. 56<s <200 mpc/h) of galaxy clustering which can be modeled by the perturbation theory. we present measurements of the anisotropic galaxy clustering from the data release 11 (dr11) cmass sample of the sdss-iii baryon oscillation spectroscopic survey (boss). we analyze the broad-range shape of the monopole and quadrupole correlation functions to obtain constraints, at the effective redshift z="0.57" of the sample, on the hubble expansion rate h(z), the angular-diameter distance $d_a(z)$, the normalized growth rate f(z)sigma_8(z), and the physical matter density omega_mh^2, and the biased amplitude of matter fluctuation bsigma_8(z). to obtain more robust measurements, we include a polynomial as the model of the systematic error. we find it works very well against the systematics we aware of. since we find that omega_mh^2 is more sensitive to the systematics, we do not include it as a recommanded quantity measured. furthermore, we modify the derived parameters to remove the correlations with omega_mh^2. it makes the measurements more robust and tighter.
To extract cosmological constraints from SDSS-III/BOSS DR11 LOWZ sample, we include smaller scales (i.e. 32<s <200 mpc/h), since the survey volume for this sample is not large enough. to model small scales, we add the model for the finger of god effect. the parameters which are not well constrained by our galaxy clustering analysis are marginalized over with wide flat priors. since no priors from other data sets (i.e., cmb) are adopted and no dark energy models are assumed, our results from boss cmass galaxy clustering alone may be combined with other data sets, i.e. cmb, sne, lensing or other galaxy clustering data to constrain the parameters of a given cosmological model.