The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: BAO measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies

We present an anisotropic analysis of the baryon acoustic oscillation (BAO) scale in the twelfth and final data release of the Baryon Oscillation Spectroscopic Survey (BOSS). We independently analyse the LOWZ and CMASS galaxy samples: the LOWZ sample contains 361 762 galaxies with an effective redshift of z_LOWZ = 0.32; the CMASS sample consists of 777 202 galaxies with an effective redshift of z_CMASS = 0.57. We extract the BAO peak position from the monopole power-spectrum moment, α₀, and from the μ² moment, α₂, where μ is the cosine of the angle to the line of sight. The μ²-moment provides equivalent information to that available in the quadrupole but is simpler to analyse. After applying a reconstruction algorithm to reduce the BAO suppression by bulk motions, we measure the BAO peak position in the monopole and μ²-moment, which are related to radial and angular shifts in scale. We report H(z_LOWZ)r_s(z_d) = (11.60 ± 0.60) × 10³ km s^-1 and D_A(z_LOWZ)/r_s(z_d) = 6.66 ± 0.16 with a cross-correlation coefficient of r_HDA = 0.41, for the LOWZ sample; and H(z_CMASS)r_s(z_d) = (14.56 ± 0.37) × 10³ km s^-1 and D_A(z_CMASS)/r_s(z_d) = 9.42 ± 0.13 with a cross-correlation coefficient of r_HDA = 0.47, for the CMASS sample. We demonstrate that our results are not affected by the fiducial cosmology assumed for the analysis. We combine these results with the measurements of the BAO peak position in the monopole and quadrupole correlation function of the same data set (Cuesta et al. 2016, companion paper) and report the consensus values: H(z_LOWZ)r_s(z_d) = (11.63 ± 0.69) × 10³ km s^-1 and D_A(z_LOWZ)/r_s(z_d) = 6.67 ± 0.15 with r_HDA = 0.35 for the LOWZ sample; H(z_CMASS)r_s(z_d) = (14.67 ± 0.42) × 10³ km s^-1 and D_A(z_CMASS)/r_s(z_d) = 9.47 ± 0.12 with r_HDA = 0.52 for the CMASS sample.