Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Cosmological implications from two decades of spectroscopic surveys at the Apache Point Observatory

Abstract

We present the cosmological implications from final measurements of clustering using galaxies, quasars, and Lyα forests from the completed Sloan Digital Sky Survey (SDSS) lineage of experiments in large-scale structure. These experiments, composed of data from SDSS, SDSS-II, BOSS, and eBOSS, offer independent measurements of baryon acoustic oscillation (BAO) measurements of angular-diameter distances and Hubble distances relative to the sound horizon, r d , from eight different samples and six measurements of the growth rate parameter, f σ 8 , from redshift-space distortions (RSD). This composite sample is the most constraining of its kind and allows us to perform a comprehensive assessment of the cosmological model after two decades of dedicated spectroscopic observation. We show that the BAO data alone are able to rule out dark-energy-free models at more than eight standard deviations in an extension to the flat, ΛCDM model that allows for curvature. When combined with Planck Cosmic Microwave Background (CMB) measurements of temperature and polarization, under the same model, the BAO data provide nearly an order of magnitude improvement on curvature constraints relative to primary CMB constraints alone. Independent of distance measurements, the SDSS RSD data complement weak lensing measurements from the Dark Energy Survey (DES) in demonstrating a preference for a flat ΛCDM cosmological model when combined with Planck measurements. The RSD and lensing measurements indicate a growth rate that is consistent with predictions from Planck temperature and polarization data and with General Relativity. When combining the results of SDSS BAO and RSD, Planck, Pantheon Type Ia supernovae (SNe Ia), and DES weak lensing and clustering measurements, all multiple-parameter extensions remain consistent with a ΛCDM model. Regardless of cosmological model, the precision on each of the three ΛCDM parameters, Ω Λ , H 0 , and σ 8 , remains at roughly 1%, showing changes of less than 0.6% in the central values between models. In a model that allows for free curvature and a time-evolving equation of state for dark energy, the combined samples produce a constraint Ω k = −0.0023 ± 0.0022. The dark energy constraints lead to w 0 = −0.912 ± 0.081 and w a = −0.48 +0.36 −0.30 , corresponding to an equation of state of w p = −1.020 ± 0.032 at a pivot redshift z p = 0.29 and a Dark Energy Figure of Merit of 92. The inverse distance ladder measurement under this model yields H 0 = 68.20 ± 0.81 km s −1 Mpc −1 , remaining in tension with several direct determination methods; the BAO data allow Hubble constant estimates that are robust against the assumption of the cosmological model. In addition, the BAO data allow estimates of H 0 that are independent of the CMB data, with similar central values and precision under a ΛCDM model. Our most constraining combination of data gives the upper limit on the sum of neutrino masses at m ν < 0.111 eV (95% confidence). Finally, we consider the improvements in cosmology constraints over the last decade by...

Cosmological constraints from H ii starburst galaxy apparent magnitude and other cosmological measurements

“…Furthermore, 10 Other local expansion rate H 0 measurements result in slightly lower central values with slightly larger error bars (Rigault et al 2015;Zhang et al 2017;Dhawan et al 2018;Fernández Arenas et al 2018;Breuval et al 2020;Efstathiou 2020;Khetan et al 2021;Rameez & Sarkar 2021;Freedman 2021). Our H 0 estimates are consistent with earlier median statistics determinations (Gott et al 2001;Calabrese et al 2012) as well as with other recent H 0 measurements (Chen et al 2017;DES Collaboration 2018;Gómez-Valent & Amendola 2018;Planck Collaboration 2020;Domínguez et al 2019;Cuceu et al 2019;Zeng & Yan 2019;Schöneberg et al 2019;Blum et al 2020;Lyu et al 2020;Philcox et al 2020;Birrer et al 2020;Denzel et al 2021;Pogosian et al 2020;Boruah et al 2021;Kim et al 2020…”

Using quasar X-ray and UV flux measurements to constrain cosmological model parameters

“…3 For observational constraints on spatial curvature see Farooq et al (2015), Chen et al (2016), Rana et al (2017), Ooba et al (2018a,c), Yu et al (2018), Park & Ratra (2019c,a), Wei (2018), DES Collaboration (2019), Li et al (2020), Handley (2019), Efstathiou & Gratton (2020), Di Valentino et al (2021b), Velasquez-Toribio & Fabris (2020, Vagnozzi et al (2020Vagnozzi et al ( , 2021, KiDS Collaboration (2021), Arjona & Nesseris (2021), Dhawan et al (2021), and references therein. 4 For observational constraints on the CDM model see Avsajanishvili et al (2015), Ryan et al (2018), Solà Peracaula et al (2018Peracaula et al ( , 2019, Zhai et al (2017), Ooba et al (2018bOoba et al ( , 2019, Park & Ratra (2018, 2019b, 2020, Sangwan et al (2018), Singh et al (2019), Ureña-López & Roy (2020), Sinha & Banerjee (2021), and references therein.…”

First direct neutrino-mass measurement with sub-eV sensitivity

“…A direct measurement of the neutrino mass could hence provide a key input to cosmological structure-formation models. In this respect, cosmological observations themselves provide stringent limits on the sum of neutrino masses 1 of ∑ m i < 0.12 eV (95 % CL) 6,7 . However, these limits strongly rely on the underlying cosmological assumptions 8,9 .…”