Unified galaxy power spectrum measurements from 6dFGS, BOSS, and eBOSS

Abstract We make use of recent developments in the analysis of galaxy redshift surveys to present an easy to use matrix-based analysis framework for the galaxy power spectrum multipoles, including wide-angle effects and the survey window function. We employ this framework to derive the deconvolved power spectrum multipoles of 6dFGS DR3, BOSS DR12 and the eBOSS DR16 quasar sample. As an alternative to the standard analysis, the deconvolved power spectrum multipoles can be used to perform a data analysis agnostic of survey specific aspects, like the window function. We show that in the case of the BOSS dataset, the Baryon Acoustic Oscillation (BAO) analysis using the deconvolved power spectra results in the same likelihood as the standard analysis. To facilitate the analysis based on both the convolved and deconvolved power spectrum measurements, we provide the window function matrices, wide-angle matrices, covariance matrices and the power spectrum multipole measurements for the datasets mentioned above. Together with this paper we publish a Python-based toolbox to calculate the different analysis components. The appendix contains a detailed user guide with examples for how a cosmological analysis of these datasets could be implemented. We hope that our work makes the analysis of galaxy survey datasets more accessible to the wider cosmology community.

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The redshift-space momentum power spectrum – I. Optimal estimation from peculiar velocity surveys

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1403 ◽

2019 ◽

Vol 487 (4) ◽

pp. 5209-5234 ◽

Cited By ~ 4

Author(s):

Cullan Howlett

Keyword(s):

Power Spectrum ◽

Measurement Errors ◽

Cosmological Parameters ◽

Power Spectra ◽

Optimal Estimation ◽

Peculiar Velocity ◽

Optimal Weights ◽

Peculiar Velocities ◽

Redshift Surveys ◽

The Galaxy

Abstract Low redshift surveys of galaxy peculiar velocities provide a wealth of cosmological information. We revisit the idea of extracting this information by directly measuring the redshift-space momentum power spectrum from such surveys. We provide a comprehensive theoretical and practical framework for estimating and fitting this from data, analogous to well-understood techniques used to measure the galaxy density power spectrum from redshift surveys. We formally derive a new estimator, which includes the effects of shot noise and survey geometry; we evaluate the variance of the estimator in the Gaussian regime; we compute the optimal weights for the estimator; we demonstrate that the measurements are Gaussian distributed, allowing for easy extraction of cosmological parameters; and we explore the effects of peculiar velocity (PV) measurement errors. We finish with a proof-of-concept using realistic mock galaxy catalogues, which demonstrates that we can measure and fit both the redshift-space galaxy density and momentum power spectra from PV surveys and that including the latter substantially improves our constraints on the growth rate of structure. We also provide theoretical descriptions for modelling the non-linear redshift-space density and momentum power spectrum multipoles, and forecasting the constraints on cosmological parameters using the Fisher information contained in these measurements for arbitrary weights. These may be useful for measurements of the galaxy density power spectrum even in the absence of peculiar velocities.

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HIR4: cosmological signatures imprinted on the cross-correlation between a 21-cm map and galaxy clustering

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2914 ◽

2020 ◽

Vol 499 (4) ◽

pp. 4613-4625

Author(s):

Feng Shi ◽

Yong-Seon Song ◽

Jacobo Asorey ◽

David Parkinson ◽

Kyungjin Ahn ◽

...

Keyword(s):

Power Spectrum ◽

Cross Correlation ◽

Broad Band ◽

Power Spectra ◽

Acoustic Oscillation ◽

Particle Simulation ◽

Band Shape ◽

Angular Diameter Distance ◽

Instrument Noise ◽

The Cross

ABSTRACT We explore the cosmological multitracer synergies between an emission-line galaxy distribution from the Dark Energy Spectroscopic Instrument and a Tianlai Project 21-cm intensity map. We use simulated maps generated from a particle simulation in the light-cone volume (Horizon Run 4), sky-trimmed and including the effects of foreground contamination, its removal and instrument noise. We first validate how the foreground residual affects the recovered 21-cm signal by putting different levels of foreground contamination into the 21-cm maps. We find that the contamination cannot be ignored in the angular autocorrelation power spectra of H i even when it is small, but it has no influence on the accuracy of the angular cross-correlation power spectra between H i and galaxies. In the foreground-cleaned map case, as information is lost in the cleaning procedure, there is also a bias in the cross-correlation power spectrum. However, we found that the bias from the cross-correlation power spectrum is scale-independent, which is easily parametrized as part of the model, while the offset in the H i autocorrelation power spectrum is non-linear. In particular, we tested that the cross-correlation power also benefits from the cancellation of the bias in the power spectrum measurement that is induced by the instrument noise, which changes the shape of the autocorrelation power spectra but leaves the cross-correlation power spectra unaffected. We then modelled the angular cross-correlation power spectra to fit the baryon acoustic oscillation feature in the broad-band shape of the angular cross-correlation power spectrum, including contamination from the residual foreground and the effect of instrument noise. We forecast a constraint on the angular diameter distance DA for the Tianlai Pathfinder redshift 0.775 < z < 1.03, giving a distance measurement with a precision of 2.7 per cent at that redshift.

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Minimum variance estimation of galaxy power spectrum in redshift space

Monthly Notices of the Royal Astronomical Society Letters ◽

10.1093/mnrasl/slaa132 ◽

2020 ◽

Vol 498 (1) ◽

pp. L77-L81

Author(s):

Maresuke Shiraishi ◽

Teppei Okumura ◽

Naonori S Sugiyama ◽

Kazuyuki Akitsu

Keyword(s):

Power Spectrum ◽

Variance Estimation ◽

Signal To Noise Ratio ◽

Minimum Variance ◽

Wide Angle ◽

Decomposition Approach ◽

Galaxy Surveys ◽

Angle Data ◽

The Galaxy ◽

Decomposition Coefficient

ABSTRACT We study an efficient way to enhance the measurability of the galaxy density and/or velocity power spectrum in redshift space. It is based on the angular decomposition with the tripolar spherical harmonic (TripoSH) basis and applicable even to galaxy distributions in wide-angle galaxy surveys. While non-trivial multipole-mode mixings are inevitable in the covariance of the Legendre decomposition coefficient commonly used in the small-angle power spectrum analysis, our analytical computation of the covariance of the TripoSH decomposition coefficient shows that such mixings are absent by virtue of high separability of the TripoSH basis, yielding the minimum variance. Via the simple signal-to-noise ratio assessment, we confirm that the detectability improvement by the TripoSH decomposition approach becomes more significant at higher multipole modes, and the hexadecapole of the density power spectrum has two orders of magnitude improvement. The TripoSH decomposition approach is expected to be applied to not only currently available survey data but also forthcoming wide-angle data, and to bring about something new or much more accurate cosmological information.

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Planck 2018 results

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833886 ◽

2020 ◽

Vol 641 ◽

pp. A8 ◽

Cited By ~ 42

Author(s):

◽

N. Aghanim ◽

Y. Akrami ◽

M. Ashdown ◽

J. Aumont ◽

...

Keyword(s):

Power Spectrum ◽

High Redshift ◽

Cosmological Parameters ◽

Power Spectra ◽

Acoustic Oscillation ◽

Minimum Variance ◽

Baryon Density ◽

Small Scale ◽

Individual Parameter ◽

Parameter Constraints

We present measurements of the cosmic microwave background (CMB) lensing potential using the final Planck 2018 temperature and polarization data. Using polarization maps filtered to account for the noise anisotropy, we increase the significance of the detection of lensing in the polarization maps from 5σ to 9σ. Combined with temperature, lensing is detected at 40σ. We present an extensive set of tests of the robustness of the lensing-potential power spectrum, and construct a minimum-variance estimator likelihood over lensing multipoles 8 ≤ L ≤ 400 (extending the range to lower L compared to 2015), which we use to constrain cosmological parameters. We find good consistency between lensing constraints and the results from the Planck CMB power spectra within the ΛCDM model. Combined with baryon density and other weak priors, the lensing analysis alone constrains σ8Ωm0.25 = 0.589 ± 0.020 (1σ errors). Also combining with baryon acoustic oscillation data, we find tight individual parameter constraints, σ8 = 0.811 ± 0.019, H0 = 67.9−1.3+1.2 km s−1 Mpc−1, and Ωm = 0.303−0.018+0.016. Combining with Planck CMB power spectrum data, we measure σ8 to better than 1% precision, finding σ8 = 0.811 ± 0.006. CMB lensing reconstruction data are complementary to galaxy lensing data at lower redshift, having a different degeneracy direction in σ8 − Ωm space; we find consistency with the lensing results from the Dark Energy Survey, and give combined lensing-only parameter constraints that are tighter than joint results using galaxy clustering. Using the Planck cosmic infrared background (CIB) maps as an additional tracer of high-redshift matter, we make a combined Planck-only estimate of the lensing potential over 60% of the sky with considerably more small-scale signal. We additionally demonstrate delensing of the Planck power spectra using the joint and individual lensing potential estimates, detecting a maximum removal of 40% of the lensing-induced power in all spectra. The improvement in the sharpening of the acoustic peaks by including both CIB and the quadratic lensing reconstruction is detected at high significance.

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Gravitational Fluctuations as an Alternative to Inflation II. CMB Angular Power Spectrum

10.20944/preprints201910.0101.v1 ◽

2019 ◽

Author(s):

Herbert W. Hamber ◽

Lu Heng Sunny Yu

Keyword(s):

Power Spectrum ◽

Power Spectra ◽

Angular Spectrum ◽

Scalar Fields ◽

Data Sets ◽

Angular Power Spectrum ◽

Fundamental Parameters ◽

Matter Power Spectrum ◽

The Galaxy ◽

Cosmological Data

Power spectra always play an important role in the theory of inflation. In particular, the ability to reproduce the galaxy matter power spectrum $ P(k) $ and the CMB temperature angular power spectrum $ C_l $’s to high accuracy is often considered a triumph of inflation. In our previous work, we presented an alternative explanation for the matter power spectrum based on nonperturbative quantum field-theoretical methods applied to Einstein’s gravity, instead of inflation models based on scalar fields. In this work, we review the basic concepts and provide further in-depth investigations. We first update the analysis with more recent data sets and error analysis, and then extend our predictions to the CMB angular spectrum coefficients $ C_l $, which we did not consider previously. Then we investigate further the potential freedoms and uncertainties associated with the fundamental parameters that are part of this picture, and show how recent cosmological data provides significant constraints on these quantities. Overall, we find good general consistency between theory and data, even potentially favoring the gravitationally-motivated picture at the largest scales. We summarize our results by outlining how this picture can be tested in the near future with increasingly accurate astrophysical measurements.

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Wide-angle effects for peculiar velocities

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2129 ◽

2020 ◽

Vol 499 (1) ◽

pp. 893-905

Author(s):

Emanuele Castorina ◽

Martin White

Keyword(s):

Correlation Function ◽

Cross Correlation ◽

Density Field ◽

Line Of Sight ◽

Wide Angle ◽

Fourier Space ◽

Translational Invariance ◽

Peculiar Velocities ◽

Redshift Surveys ◽

The Galaxy

ABSTRACT The line-of-sight peculiar velocities of galaxies contribute to their observed redshifts, breaking the translational invariance of galaxy clustering down to a rotational invariance around the observer. This becomes important when the line-of-sight direction varies significantly across a survey, leading to what are known as ‘wide-angle’ effects in redshift-space distortions. Wide-angle effects will also be present in measurements of the momentum field, i.e. the galaxy density-weighted velocity field, in upcoming peculiar velocity surveys. In this work, we study how wide-angle effects modify the predicted correlation function and power spectrum for momentum statistics, both in autocorrelation and in cross-correlation with the density field. Using both linear theory and the Zel'dovich approximation, we find that deviations from the plane-parallel limit are large and could become important in data analysis for low-redshift surveys. We point out that even multipoles in the cross-correlation between density and momentum are non-zero regardless of the choice of line of sight, and therefore contain new cosmological information that could be exploited. We discuss configuration space, Fourier space, and spherical analyses; providing exact expressions in each case rather than relying on an expansion in small angles. We hope these expressions will be of use in the analysis of upcoming surveys for redshift-space distortions and peculiar velocities.

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hmcode-2020: improved modelling of non-linear cosmological power spectra with baryonic feedback

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab082 ◽

2021 ◽

Vol 502 (1) ◽

pp. 1401-1422

Author(s):

A J Mead ◽

S Brieden ◽

T Tröster ◽

C Heymans

Keyword(s):

Power Spectrum ◽

Equations Of State ◽

Power Spectra ◽

Acoustic Oscillation ◽

Worst Case ◽

Wide Range ◽

Non Linear ◽

Hydrodynamical Simulations ◽

Energy Equations ◽

The Impact

ABSTRACT We present an updated version of the hmcode augmented halo model that can be used to make accurate predictions of the non-linear matter power spectrum over a wide range of cosmologies. Major improvements include modelling of baryon-acoustic oscillation (BAO) damping in the power spectrum and an updated treatment of massive neutrinos. We fit our model to simulated power spectra and show that we can match the results with an root mean square (RMS) error of 2.5 per cent across a range of cosmologies, scales $k \lt 10\, h\, \mathrm{Mpc}^{-1}$, and redshifts z < 2. The error rarely exceeds 5 per cent and never exceeds 16 per cent. The worst-case errors occur at z ≃ 2, or for cosmologies with unusual dark energy equations of state. This represents a significant improvement over previous versions of hmcode, and over other popular fitting functions, particularly for massive-neutrino cosmologies with high neutrino mass. We also present a simple halo model that can be used to model the impact of baryonic feedback on the power spectrum. This six-parameter physical model includes gas expulsion by active galactic nuclei (AGN) feedback and encapsulates star formation. By comparing this model to data from hydrodynamical simulations, we demonstrate that the power spectrum response to feedback is matched at the <1 per cent level for z < 1 and $k\lt 20\, h\, \mathrm{Mpc}^{-1}$. We also present a single-parameter variant of this model, parametrized in terms of feedback strength, which is only slightly less accurate. We make code available for our non-linear and baryon models at https://github.com/alexander-mead/HMcode and it is also available within camb and soon within class.

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Mitigating contamination in LSS surveys: a comparison of methods

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab709 ◽

2021 ◽

Vol 503 (4) ◽

pp. 5061-5084 ◽

Cited By ~ 3

Author(s):

Noah Weaverdyck ◽

Dragan Huterer

Keyword(s):

Power Spectrum ◽

Large Scale ◽

Power Spectra ◽

Dark Energy Survey ◽

Current State ◽

Galaxy Distribution ◽

The Galaxy ◽

Improved Estimators ◽

Mitigation Methods ◽

Energy Survey

ABSTRACT Future large-scale structure surveys will measure the locations and shapes of billions of galaxies. The precision of such catalogues will require meticulous treatment of systematic contamination of the observed fields. We compare several existing methods for removing such systematics from galaxy clustering measurements. We show how all the methods, including the popular pseudo-Cℓ Mode Projection and Template Subtraction methods, can be interpreted under a common regression framework and use this to suggest improved estimators. We show how methods designed to mitigate systematics in the power spectrum can be used to produce clean maps, which are necessary for cosmological analyses beyond the power spectrum, and we extend current methods to treat the next-order multiplicative contamination in observed maps and power spectra, which reduced power spectrum errors from $\Delta \chi ^2_{\rm C_\ell }\simeq 10$ to ≃ 1 in simulated analyses. Two new mitigation methods are proposed, which incorporate desirable features of current state-of-the-art methods while being simpler to implement. Investigating the performance of all the methods on a common set of simulated measurements from Year 5 of the Dark Energy Survey, we test their robustness to various analysis cases. Our proposed methods produce improved maps and power spectra when compared to current methods, while requiring almost no user tuning. We end with recommendations for systematics mitigation in future surveys, and note that the methods presented are generally applicable beyond the galaxy distribution to any field with spatial systematics.

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