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تسجيل مستخدم جديدA Detection of the Baryon Acoustic Oscillation Features in the SDSS BOSS DR12 Galaxy Bispectrum
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We present the first high significance detection ($4.1sigma$) of the Baryon Acoustic Oscillations (BAO) feature in the galaxy bispectrum of the twelfth data release (DR12) of the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS sample ($0.43 leq z leq 0.7$). We measured the scale dilation parameter, $alpha$, using the power spectrum, bispectrum, and both simultaneously for DR12, plus 2048 MultiDark-PATCHY mocks in the North and South Galactic Caps (NGC and SGC, respectively), and the volume weighted averages of those two samples (N+SGC). The fitting to the mocks validated our analysis pipeline, yielding values consistent with the mock cosmology. By fitting to the power spectrum and bispectrum separately, we tested the robustness of our results, finding consistent values from the NGC, SGC and N+SGC in all cases. We found $D_{mathrm{V}} = 2032 pm 24 (mathrm{stat.}) pm 15 (mathrm{sys.})$ Mpc, $D_{mathrm{V}} = 2038 pm 55 (mathrm{stat.}) pm 15 (mathrm{sys.})$ Mpc, and $D_{mathrm{V}} = 2031 pm 22 (mathrm{stat.}) pm 10 (mathrm{sys.})$ Mpc from the N+SGC power spectrum, bispectrum and simultaneous fitting, respectively.
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We apply the Alcock-Paczynski (AP) test to the stacked voids identified using the large-scale structure galaxy catalog from the Baryon Oscillation Spectroscopic Survey (BOSS). This galaxy catalog is part of the Sloan Digital Sky Survey (SDSS) Data Re
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[abridged] We present an anisotropic analysis of the baryonic acoustic oscillation (BAO) scale in the twelfth and final data release of the Baryonic Oscillation Spectroscopic Survey (BOSS). We independently analyse the LOWZ and CMASS galaxy samples:
the LOWZ sample contains contains 361 762 galaxies with an effective redshift of $z_{rm LOWZ}=0.32$; the CMASS sample consists of 777 202 galaxies with an effective redshift of $z_{rm CMASS}=0.57$. We extract the BAO peak position from the monopole power spectrum moment, $alpha_0$, and from the $mu^2$ moment, $alpha_2$, where $mu$ is the cosine of the angle to the line-of-sight. The $mu^2$-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 $mu^2$-moment, which are related to radial and angular shifts in scale. We report $H(z_{rm LOWZ})r_s(z_d)=(11.60pm0.60)cdot10^3 {rm km}s^{-1}$ and $D_A(z_{rm LOWZ})/r_s(z_d)=6.66pm0.16$ with a cross-correlation coefficient of $r_{HD_A}=0.41$, for the LOWZ sample; and $H(z_{rm CMASS})r_s(z_d)=(14.56pm0.37)cdot10^3 {rm km}s^{-1}$ and $D_A(z_{rm CMASS})/r_s(z_d)=9.42pm0.13$ with a cross-correlation coefficient of $r_{HD_A}=0.47$, for the CMASS sample. We combine these results with the measurements of the BAO peak position in the monopole and quadrupole correlation function of the same dataset citep[][companion paper]{Cuestaetal2015} and report the consensus values: $H(z_{rm LOWZ})r_s(z_d)=(11.63pm0.69)cdot10^3 {rm km}s^{-1}$ and $D_A(z_{rm LOWZ})/r_s(z_d)=6.67pm0.15$ with $r_{HD_A}=0.35$ for the LOWZ sample; $H(z_{rm CMASS})r_s(z_d)=(14.67pm0.42)cdot10^3 {rm km}s^{-1}$ and $D_A(z_{rm CMASS})/r_s(z_d)=9.47pm0.12$ with $r_{HD_A}=0.52$ for the CMASS sample.
We measure and analyse the clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) relative to the line-of-sight (LOS), for LOWZ and CMASS galaxy samples drawn from the final Data Release 12 (DR12). The LOWZ sample contains 361,762 galaxies
with an effective redshift of $z_{rm lowz}=0.32$, and the CMASS sample 777,202 galaxies with an effective redshift of $z_{rm cmass}=0.57$. From the power spectrum monopole and quadrupole moments around the LOS, we measure the growth of structure parameter $f$ times the amplitude of dark matter density fluctuations $sigma_8$ by modeling the Redshift-Space Distortion signal. When the geometrical Alcock-Paczynski effect is also constrained from the same data, we find joint constraints on $fsigma_8$, the product of the Hubble constant and the comoving sound horizon at the baryon drag epoch $H(z)r_s(z_d)$, and the angular distance parameter divided by the sound horizon $D_A(z)/r_s(z_d)$. We find $f(z_{rm lowz})sigma_8(z_{rm lowz})=0.394pm0.062$, $D_A(z_{rm lowz})/r_s(z_d)=6.35pm0.19$, $H(z_{rm lowz})r_s(z_d)=(11.41pm 0.56),{10^3rm km}s^{-1}$ for the LOWZ sample, and $f(z_{rm cmass})sigma_8(z_{rm cmass})=0.444pm0.038$, $D_A(z_{rm cmass})/r_s(z_d)=9.42pm0.15$, $H(z_{rm cmass})r_s(z_d)=(13.92 pm 0.44), {10^3rm km}s^{-1}$ for the CMASS sample. We find general agreement with previous BOSS DR11 measurements. Assuming the Hubble parameter and angular distance parameter are fixed at fiducial $Lambda$CDM values, we find $f(z_{rm lowz})sigma_8(z_{rm lowz})=0.485pm0.044$ and $f(z_{rm cmass})sigma_8(z_{rm cmass})=0.436pm0.022$ for the LOWZ and CMASS samples, respectively.
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