The extended Baryon Oscillation Spectroscopic Survey: a cosmological forecast

Abstract

We present a science forecast for the eBOSS survey. Focusing on discrete tracers, we forecast the expected accuracy of the baryonic acoustic oscillation (BAO), the redshift-space distortion (RSD) measurements, the f NL parameter quantifying the primordial non-Gaussianity, the dark energy and modified gravity parameters. We also use the line-of-sight clustering in the Ly-α forest to constrain the total neutrino mass. We find that eBOSS LRGs, ELGs and Clustering Quasars (CQs) can achieve a precision of 1%, 2.2% and 1.6%, respectively, for spherically averaged BAO distance measurements. Using the same samples, the constraint on f σ 8 is expected to be 2.5%, 3.3% and 2.8% respectively. For primordial non-Gaussianity, eBOSS alone can reach an accuracy of σ(f NL ) ∼ 10−15. eBOSS can at most improve the dark energy Figure of Merit (FoM) by a factor of 3 for the Chevallier-Polarski-Linder (CPL) parametrisation, and can well constrain three eigenmodes for the general equation-of-state parameter. eBOSS can also significantly improve constraints on modified gravity parameters by providing the RSD information, which is highly complementary to constraints obtained from weak lensing measurements. A principle component analysis (PCA) shows that eBOSS can measure the eigenmodes of the effective Newton's constant to 2% precision; this is a factor of 10 improvement over that achievable without eBOSS. Finally, we derive the eBOSS constraint (combined with Planck, DES and BOSS) on the total neutrino mass, σ(Σm ν ) = 0.03eV (68% CL), which in principle makes it possible to distinguish between the two scenarios of neutrino mass hierarchies.

The Color and Stellar Mass Dependence of Small-scale Galaxy Clustering in SDSS-III BOSS

“…We also look forward to larger data sets with eBOSS (Zhao et al 2016), the Subaru Prime Focus Spectrograph (PFS; Takada et al 2014), DESI (Levi et al 2013), Euclid (Laureijs 2009;Laureijs et al 2011), LSST (Tyson 2002), and WFIRST (Spergel et al 2013a,b) that can be matched up to deeper imaging.…”

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

“…Forecasts in Zhao et al (2016) predict 1% precision on isotropic BAO with 7000 deg 2 for the final eBOSS LRG sample (when combined with the high-redshift tail of CMASS). For the current footprint with A eff =1844 deg 2 , the forecast scales to a 1.95% BAO measurement assuming that the error is Figure 13.…”

“…The main goal of eBOSS is to measure BAO distances at 1.6% precision level using 500k clustering quasars, 1.4% using Lyα forests, 2.2% with 200k emission line galaxies (ELGs), and 1% from 300k luminous red galaxies (LRGs). With these galaxy and quasar samples, eBOSS will produce the best measurements of the growth rate of structures from RSD: 2.8%, 3.3%, and 2.5% precision, respectively, from quasars, ELGs, and LRGs (Zhao et al 2016).…”

An Evaluation of Cosmological Models from the Expansion and Growth of Structure Measurements

“…Clearly in this model space the range of variation in observed quantities is quite small. In this figure, we also include projections for eBOSS (Dawson et al 2016;Zhao et al 2016) as open symbols. Simple parameterizations of the equation of state of dark energy w allow us to study aspects of the observed acceleration without explicit assumptions about its physical cause.…”