Hefty enhancement of cosmological constraints from the DES Y1 data using a hybrid effective field theory approach to galaxy bias
Journal of Cosmology and Astroparticle Physics IOP Publishing 2021:09 (2021) 020-020
Linear anisotropies in dispersion-measure-based cosmological observables
Physical Review D - Particles, Fields, Gravitation and Cosmology American Physical Society 103 (2021) 123544
Abstract:
We derive all contributions to the dispersion measure (DM) of electromagnetic pulses to linear order in cosmological perturbations, including both density fluctuations and relativistic effects. We then use this result to calculate the power spectrum of DM-based cosmological observables to linear order in perturbations. In particular we study two cases: maps of the dispersion measure from a set of localized sources (including the effects of source clustering), and fluctuations in the density of DM-selected sources. The impact of most relativistic effects is limited to large angular scales, and is negligible for all practical applications in the context of ongoing and envisaged observational programmes targetting fast radio bursts. We compare the leading contributions to DM-space clustering, including the effects of gravitational lensing, and find that the signal is dominated by the fluctuations in the free electron column density, rather than the local source clustering or lensing contributions. To compensate for the disappointing irrelevance of relativistic effects, we re-derive them in terms of the geodesic equation for massive particles in a perturbed Friedmann-Robertson-Walker metric.Microwave spectro-polarimetry of matter and radiation across space and time
Experimental Astronomy Springer Nature 51:3 (2021) 1471-1514
Strong detection of the CMB lensing and galaxy weak lensing cross-correlation from ACT-DR4, Planck Legacy, and KiDS-1000
Astronomy & Astrophysics EDP Sciences 649 (2021) A146-A146
Abstract:
<jats:p>We measured the cross-correlation between galaxy weak lensing data from the Kilo Degree Survey (KiDS-1000, DR4) and cosmic microwave background (CMB) lensing data from the Atacama Cosmology Telescope (ACT, DR4) and the <jats:italic>Planck</jats:italic> Legacy survey. We used two samples of source galaxies, selected with photometric redshifts, (0.1 < <jats:italic>z</jats:italic><jats:sub>B</jats:sub> < 1.2) and (1.2 < <jats:italic>z</jats:italic><jats:sub>B</jats:sub> < 2), which produce a combined detection significance of the CMB lensing and weak galaxy lensing cross-spectrum of 7.7<jats:italic>σ</jats:italic>. With the lower redshift galaxy sample, for which the cross-correlation was detected at a significance of 5.3<jats:italic>σ</jats:italic>, we present joint cosmological constraints on the matter density parameter, Ω<jats:sub>m</jats:sub>, and the matter fluctuation amplitude parameter, <jats:italic>σ</jats:italic><jats:sub>8</jats:sub>, marginalising over three nuisance parameters that model our uncertainty in the redshift and shear calibration as well as the intrinsic alignment of galaxies. We find our measurement to be consistent with the best-fitting flat ΛCDM cosmological models from both <jats:italic>Planck</jats:italic> and KiDS-1000. We demonstrate the capacity of CMB weak lensing cross-correlations to set constraints on either the redshift or shear calibration by analysing a previously unused high-redshift KiDS galaxy sample (1.2 < <jats:italic>z</jats:italic><jats:sub>B</jats:sub> < 2), with the cross-correlation detected at a significance of 7<jats:italic>σ</jats:italic>. This analysis provides an independent assessment for the accuracy of redshift measurements in a regime that is challenging to calibrate directly owing to known incompleteness in spectroscopic surveys.</jats:p>Probing galaxy bias and intergalactic gas pressure with KiDS Galaxies-tSZ-CMB lensing cross-correlations
Astronomy & Astrophysics EDP Sciences (2021)