Baryon acoustic oscillation methods for generic curvature: application to the SDSS-III Baryon Oscillation Spectroscopic Survey

Heinesen, Asta; Li, Yong-Zhuang; Wiltshire, David L.

doi:10.1088/1475-7516/2019/03/003

Cited by 11 publications

(23 citation statements)

References 87 publications

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“…We assume the peak of the BAO feature r to be a "standard ruler" independent of redshift. This approximation is good in ΛCDM cosmology as confirmed with ΛCDM mock catalogues in [30] using standard ΛCDM template procedures and in [32] using the empirical model presented here. From the results in [30] and [32] we can expect shifts of the BAO scale of < ∼ 0.5% in a ΛCDM universe at redshifts 0.3.…”

Section: Empirical Model For the Correlation Functionsupporting

confidence: 73%

“…We follow [32] and consider the observer-adapted spherically-symmetric template metrics 1 ds 2 = −α(t, r) 2 c 2 dt 2 + g rr (t, r) dr 2 + g θθ (t, r) dθ 2 + cos 2 (θ)dφ 2 , (2.1)…”

Section: Models Under Investigationmentioning

confidence: 99%

“…As outlined in appendix A of [32], for small separations of points P 1 and P 2 on the t = T hypersurface as compared to variations of the adapted spatial metric (2.2), the geodesic distance D T (P 1 , P 2 ) between the points P 1 and P 2 represented by coordinates (z 1 , θ 1 , φ 1 ) and (z 2 , θ 2 , φ 2 ) is D 2 T (P 1 , P 2 ) ≈ g zz (t = T,z)(δz) 2 + g θθ (t = T,z)(δΘ) 2 , (2.4) wherez = (z 1 + z 2 )/2 is the intermediate redshift, δz = z 2 − z 1 is the separation in redshift, and δΘ is the separation in angle δΘ = arccos [sin(θ 1 ) sin(θ 2 ) + cos(θ 1 ) cos(θ 2 ) cos(φ 2 − φ 1 )] (2.5)…”

Section: (23)mentioning

confidence: 99%

“…Using the definitions (2.6) and (2.9), we can rewrite the approximation (2.7) for points with mean redshift z as [32] (D tr ) 2 ≈ α 2 (z)D 2 1 + ψ(z)µ 2 (1 + (z)) 2 , ψ(z) ≡ (1 + (z)) 6 − 1.…”

Section: Alcock-paczyński Scalingmentioning

confidence: 99%

“…We follow [32] and consider the model for the 2-point correlation function (A.7) 12) as formulated in the underlying "true" cosmology, where r denotes the BAO scale or a characteristic scale shifted with respect to the BAO scale. (See the discussion below on calibration of the BAO scale.)…”

Section: Empirical Model For the Correlation Functionmentioning

confidence: 99%

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Quantifying the accuracy of the Alcock-Paczyński scaling of baryon acoustic oscillation measurements

Heinesen

Wiltshire

2020

J. Cosmol. Astropart. Phys.

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We investigate -in a generic setting -the regime of applicability of the Alcock-Paczyński (AP) scaling conventionally applied to test different cosmological models, given a fiducial measurement of the baryon acoustic oscillation (BAO) characteristic scale in the galaxy 2-point correlation function. We quantify the error in conventional AP scaling methods, for which our ignorance about the true cosmology is parameterised in terms of two constant AP scaling parameters. We propose a new, and as it turns out, improved version of the constant AP scaling, also consisting of two scaling parameters.The two constant AP scaling methods are almost indistinguishable when the fiducial model used in data reduction and the "true" underlying cosmology are not differing substantially in terms of metric gradients, but are otherwise expected to differ. Our new methods can be applied to existing analyses through a reinterpretation of the results of the conventional AP scaling. This reinterpretation might be important in model universes where curvature gradients above the scale of galaxies are significant.We test our theoretical findings on ΛCDM mock catalogues. The conventional constant AP scaling methods are surprisingly successful for pairs of large-scale metrics, but eventually break down when toy models allowing for large metric gradients are tested. The new constant AP scaling methods proposed in this paper are efficient for all test models examined. We find systematic errors of ∼1% in the recovery of the BAO scale when the true model is distant from the fiducial, which cannot be attributed to any constant AP approximation. The level of systematic uncertainty is robust to the exact fitting method employed. This indicates that caution must be taken with the error budget when extrapolating the BAO acoustic scale measurements obtained in the standard literature. 4 The Alcock-Paczyński scaling and the BAO feature 13 5 Testing the predicted shift of the BAO feature with mock catalogues 15 5.1 The mock catalogues 15 5.2 The likelihood function and the fitting procedure 16 5.3 Large-scale model cosmologies 18 5.4 Toy models with large metric gradients 24 6 Discussion 29 Appendix A The 2-point correlation function and the Landy-Szalay estimators 31 A.1 The 2-point correlation 31 A.2 The Landy-Szalay estimators 33 Appendix B Conjecture of improved AP scaling 35 Appendix C Bounds on the AP error terms 38 C.1 Bounds on the magnitude of ∆ α 38 C.2 Bounds on the magnitude of ∆ 39 -1 -The distribution of gravitationally-bound matter in space serves as an important probe of large-scale dynamics of the Universe. In the Lambda Cold Dark Matter (ΛCDM) cosmology -or indeed any Friedmann-Lemaître-Robertson-Walker (FLRW) model beginning in a hot big bang -the primordial plasma exhibits sound waves which are imprinted as a characteristic scale in the matter distribution after the decoupling of the baryons from the photons [1, 2]. This characteristic baryon acoustic oscillation (BAO) scale is predicted to be seen as an excess in the autocorrelation o...

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Section: Empirical Model For the Correlation Functionsupporting

confidence: 73%

“…We follow [32] and consider the observer-adapted spherically-symmetric template metrics 1 ds 2 = −α(t, r) 2 c 2 dt 2 + g rr (t, r) dr 2 + g θθ (t, r) dθ 2 + cos 2 (θ)dφ 2 , (2.1)…”

Section: Models Under Investigationmentioning

confidence: 99%

Section: (23)mentioning

confidence: 99%

Section: Alcock-paczyński Scalingmentioning

confidence: 99%

Section: Empirical Model For the Correlation Functionmentioning

confidence: 99%

See 3 more Smart Citations

Quantifying the accuracy of the Alcock-Paczyński scaling of baryon acoustic oscillation measurements

Heinesen

Wiltshire

2020

J. Cosmol. Astropart. Phys.

Self Cite

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Cosmology intertwined: A review of the particle physics, astrophysics, and cosmology associated with the cosmological tensions and anomalies

Abdalla

Abellán

Aboubrahim

et al. 2022

Journal of High Energy Astrophysics

608

312

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Is the observable Universe consistent with the cosmological principle?

Aluri

Cea

Chingangbam

et al. 2023

Class. Quantum Grav.

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The Cosmological Principle (CP) -- the notion that the Universe is spatially isotropic and homogeneous on large scales -- underlies a century of progress in cosmology. It is conventionally formulated through the Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) cosmologies as the spacetime metric, and culminates in the successful and highly predictive $\Lambda$-Cold-Dark-Matter ($\Lambda$CDM) model. Yet, tensions have emerged within the $\Lambda$CDM model, most notably a statistically significant discrepancy in the value of the Hubble constant, $H_0$. Since the notion of cosmic expansion determined by a single parameter is intimately tied to the CP, implications of the $H_0$ tension may extend beyond $\Lambda$CDM to the CP itself. This review surveys current observational hints for deviations from the expectations of the CP, highlighting synergies and disagreements that warrant further study. Setting aside the debate about individual large structures, potential deviations from the CP include variations of cosmological parameters on the sky, discrepancies in the cosmic dipoles, and mysterious alignments in quasar polarizations and galaxy spins. While it is possible that a host of observational systematics are impacting results, it is equally plausible that precision cosmology may have outgrown the FLRW paradigm, an extremely pragmatic but non-fundamental symmetry assumption.

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Baryon acoustic oscillation methods for generic curvature: application to the SDSS-III Baryon Oscillation Spectroscopic Survey

Cited by 11 publications

References 87 publications

Quantifying the accuracy of the Alcock-Paczyński scaling of baryon acoustic oscillation measurements

Quantifying the accuracy of the Alcock-Paczyński scaling of baryon acoustic oscillation measurements

Cosmology intertwined: A review of the particle physics, astrophysics, and cosmology associated with the cosmological tensions and anomalies

Is the observable Universe consistent with the cosmological principle?

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