DESI measures BAO scales in six redshift bins with 0.52% combined precision using 5.7 million objects, detecting the signal at up to 9.1 sigma and finding larger scales than Planck LCDM at z<0.8.
Measuring the cosmological constant with redshift surveys
9 Pith papers cite this work. Polarity classification is still indexing.
abstract
It has been proposed that the cosmological constant $\Lambda$ might be measured from geometric effects on large-scale structure. A positive vacuum density leads to correlation-function contours which are squashed in the radial direction when calculated assuming a matter-dominated model. We show that this effect will be somewhat harder to detect than previous calculations have suggested: the squashing factor is likely to be $<1.3$, given realistic constraints on the matter contribution to $\Omega$. Moreover, the geometrical distortion risks being confused with the redshift-space distortions caused by the peculiar velocities associated with the growth of galaxy clustering. These depend on the density and bias parameters via the combination $\beta\equiv \Omega^{0.6}/b$, and we show that the main practical effect of a geometrical flattening factor $F$ is to simulate gravitational instability with $\beta_{\rm eff}\simeq 0.5(F-1)$. Nevertheless, with datasets of sufficient size it is possible to distinguish the two effects; we discuss in detail how this should be done. New-generation redshift surveys of galaxies and quasars are potentially capable of detecting a non-zero vacuum density, if it exists at a cosmologically interesting level.
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astro-ph.CO 9representative citing papers
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Joint power spectrum and bispectrum analysis from future HI intensity mapping surveys improves constraints on primordial feature amplitudes by 30-40% and achieves percent-level precision on oscillation frequencies when combined with CMB measurements.
First systematic validation shows Hybrid Bias Expansion model for galaxy bispectrum remains accurate up to k=0.25 h/Mpc in DESI-like mocks, outperforming tree-level EFT.
Gaia quasar proper motions show a significant quadrupole signal matching an axisymmetric Bianchi I anisotropy model, but the amplitude does not increase with redshift as the model requires and the inferred local shear exceeds expectations.
Neighbor-density-weighted marked correlation functions improve FoM for Ω_m–σ_8 by 1.7–2.5× over standard 2PCF using emulators from 129 w0waCDM+∑m_ν simulations.
Halo reconstruction from redshift-space galaxies allows unbiased EFT full-shape inference with >20% tighter fσ8 constraints and stable results to smaller scales on DESI mocks.
Forecasts show that future 21 cm surveys can deliver moderate constraints on the scale-dependent growth index and HI bias in viable f(R) models.
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Mapping the Universe as a Bianchi I cosmology with Gaia data
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Cosmological constraints from neighbor-density-weighted marked correlation functions
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