We present a measurement of two-dimensional ( 2D ) redshift-space power spectrum for the Baryon Oscillation Spectroscopic Survey ( BOSS ) Data Release 11 CMASS galaxies in the North Galactic Cap ( NGC ) based on the method developed by ( 37 ) .
In this method , we first measure the 2D redshift-space correlation function for the CMASS galaxies , and obtain the 2D power spectrum based on Fourier Transform of the correlation function .
The method is tested with an N-body mock galaxy catalog , which demonstrates that the method can yield an accurate and unbiased measurement of the redshift-space power spectrum given the input 2D correlation function is correct .
Compared with previous measurements in literature that are usually based on direct Fourier Transform in redshift space , our method has the advantages that the window function and shot-noise are fully corrected , while those measured in previous studies for the CMASS galaxies are usually the one convolved with the window function .
In fact , our 2D power spectrum , by its construction , can accurately reproduce the 2D correlation function , and in the meanwhile can reproduce , for example , the 2D power spectrum of ( 6 ) accurately if ours is convolved with the window function they provided .
Thus , our measurement can facilitate a direct comparison with the theoretical predictions .
With this accurate measurement of the 2D power spectrum , we then develop a method to measure the structure growth rate , by separating the anisotropic redshift-space power spectrum from the isotropic real-space power spectrum .
We have also carefully corrected for the nonlinearities in the mapping from real space to redshift space , according to the theoretical model of ( 95 ) .
Finally , we obtain f ( { z _ { \mathrm { eff } } } ) \sigma _ { 8 } ( { z _ { \mathrm { eff } } } ) = 0.438 \pm 0.037 at the effective redshift { z _ { \mathrm { eff } } } = 0.57 , where f ( { z _ { \mathrm { eff } } } ) is the linear growth rate and \sigma _ { 8 } ( { z _ { \mathrm { eff } } } ) is the rms density fluctuation in the sphere of comoving radius 8 h ^ { -1 } { Mpc } at { z _ { \mathrm { eff } } } .
The result is useful for constraining cosmological parameters .
The measurements of 2D power spectrum will be released soon .