DESI DR2 and ACT DR6 data yield 17σ LRG-velocity, 8.3σ ELG-velocity, and 6.8σ QSO-velocity detections plus a 3.1σ velocity-velocity signal, producing f_NL^loc = 15.9_{-34.4}^{+34.6} from the velocity field.
Testing cosmological structure formation using redshift-space distortions
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abstract
Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for observing the build-up of cosmological structure. In this paper we develop and test a new statistic based on anisotropies in the measured galaxy power spectrum, which is independent of galaxy bias and matches the matter power spectrum shape on large scales. The amplitude provides a constraint on the derivative of the linear growth rate through f.sigma_8. This demonstrates that spectroscopic galaxy surveys offer many of the same advantages as weak lensing surveys, in that they both use galaxies as test particles to probe all matter in the Universe. They are complementary as redshift-space distortions probe non-relativistic velocities and therefore the temporal metric perturbations, while weak lensing tests the sum of the temporal and spatial metric perturbations. The degree to which our estimator can be pushed into the non-linear regime is considered and we show that a simple Gaussian damping model, similar to that previously used to model the behaviour of the power spectrum on very small scales, can also model the quasi-linear behaviour of our estimator. This enhances the information that can be extracted from surveys for LCDM models.
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astro-ph.CO 4representative citing papers
Final Planck CMB data confirms the flat 6-parameter ΛCDM model with Ω_c h² = 0.120 ± 0.001, Ω_b h² = 0.0224 ± 0.0001, n_s = 0.965 ± 0.004, τ = 0.054 ± 0.007, H_0 = 67.4 ± 0.5 km/s/Mpc, and no strong evidence for extensions.
Transformer and GBDT models trained on AbacusSummit mocks for DESI LRGs/ELGs recover nonlinear velocity power spectra and cross-correlations better than linear theory across a wider range of scales, with applications to kSZ analyses.
Roman Space Telescope forecasts using Hα galaxy mocks yield m_ν < 0.276 eV (68% CL) with Planck priors via EFT of LSS, and m_ν < 0.36 eV via model-independent phenomenological analysis.
citing papers explorer
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Measurement of the galaxy-velocity power spectrum of DESI tracers with the kinematic Sunyaev-Zeldovich effect using DESI DR2 and ACT DR6
DESI DR2 and ACT DR6 data yield 17σ LRG-velocity, 8.3σ ELG-velocity, and 6.8σ QSO-velocity detections plus a 3.1σ velocity-velocity signal, producing f_NL^loc = 15.9_{-34.4}^{+34.6} from the velocity field.
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Planck 2018 results. VI. Cosmological parameters
Final Planck CMB data confirms the flat 6-parameter ΛCDM model with Ω_c h² = 0.120 ± 0.001, Ω_b h² = 0.0224 ± 0.0001, n_s = 0.965 ± 0.004, τ = 0.054 ± 0.007, H_0 = 67.4 ± 0.5 km/s/Mpc, and no strong evidence for extensions.
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Full Nonlinear Velocity Reconstruction With Transformer and Ensemble Tree Machine Learning
Transformer and GBDT models trained on AbacusSummit mocks for DESI LRGs/ELGs recover nonlinear velocity power spectra and cross-correlations better than linear theory across a wider range of scales, with applications to kSZ analyses.
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Forecasting neutrino mass constraints from the Nancy Grace Roman Space Telescope
Roman Space Telescope forecasts using Hα galaxy mocks yield m_ν < 0.276 eV (68% CL) with Planck priors via EFT of LSS, and m_ν < 0.36 eV via model-independent phenomenological analysis.