The SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations at Redshift of 0.72 with the DR14 Luminous Red Galaxy Sample

Abstract

The extended Baryon Oscillation Spectroscopic Survey (eBOSS) Data Release 14 sample includes 80,118 luminous red galaxies (LRGs). By combining these galaxies with the high-redshift tail of the BOSS galaxy sample, we form a sample of LRGs at an effective redshift z=0.72, covering an effective volume of 0.9 Gpc 3 . We account for spurious fluctuations caused by targeting and by redshift failures, which were validated on a set of mock catalogs. This analysis is sufficient to provide a 2.5% measurement of spherically averaged baryon acoustic oscillations (BAO), D z rr 0.72 2377 61,fid = = -+ ( ) ( )Mpc, at 2.8σ of significance. Together with the recent quasar-based BAO measurement at z=1.5 and forthcoming emission line galaxy-based measurements, this measurement demonstrates that eBOSS is fulfilling its remit of extending the range of redshifts covered by such measurements, laying the groundwork for forthcoming surveys such as the Dark Energy Spectroscopic Survey and Euclid.

The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR14 LRG sample: structure growth rate measurement from the anisotropic LRG correlation function in the redshift range 0.6 < z < 1.0

“…The left panel of Figure 14 shows the difference between our FS fits and the expected value compared to those from the anisotropic BAO parameters, the later taken from Bautista et al (2017). The dispersion for the anisotropic warping, , from BAO fits is slightly larger compared to the FS best fits.…”

“…Our analysis was performed considering two cases: 1) Considering only the multipoles up to = 2 (skiping the hexadecapole), and therefore following the methodology used in previous analysis performed with the LRG sample, which we will refer to as "ξ 0 + ξ 2 ". We also consider the effect of extending the multipoles up to = 4 and ussing the full range for all multipoles, which we will refer to as "ξ 0 + ξ 2 + ξ 4 " Section 6.3 compares our results to those obtained in Bautista et al (2018), which is a previous analysis using this same sample. In Section 6.4 we describe our tests of the effect of spectroscopic incompleteness and the effects of different mitigation techniques for dealing with redshift failures systematics.…”

“…The first is a BOSSlike catalog where traditional weighting schemes are applied, described in Ross et al (2017), to the data. The second is denoted as the "official catalog", and it was used in Bautista et al (2017) for performing the BAO analysis. Here some improvements with respect to previous analysis were implemented: the forward modeling of the randoms for the spectroscopic incompleteness and the multilinear regression and subsampling of the randoms for the photometric systematics.…”

“…• Multi-regression Method: We followed the same methodology presented in Bautista et al (2017), where the correlation between systematic maps and density were computed using a multilinear regression of the seven systematic maps instead of the iterative method. The advantage of this method is that it does not assume the systematics are independent, as does the iterative method.…”

“…The model for failures is then applied to the random sample by subsampling, mimicking the patterns retrieved in the model. For more details about this modeling we refer the reader to Bautista et al (2017).…”