Modelling the impact of intrinsic size and luminosity correlations on magnification estimation

Ciarlariello, Sandro; Crittenden, Robert

doi:10.1093/mnras/stw2052

Cited by 3 publications

(2 citation statements)

References 47 publications

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“…Finally, the EFT prescription for scalar biased tracers can also be applied to intrinsic correlations of galaxy sizes, as well as other galaxy properties. Size correlations have recently been detected in current surveys [57] and can pose a challenging contaminant in the attempt to constrain cosmological magnification via observed galaxy size perturbations [57][58][59].…”

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confidence: 99%

An EFT description of galaxy intrinsic alignments

Vlah

Chisari

Schmidt

2020

J. Cosmol. Astropart. Phys.

146

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We present a general perturbative effective field theory (EFT) description of galaxy shape correlations, which are commonly known as intrinsic alignments. This rigorous approach extends current analytical modelling strategies in that it only relies on the equivalence principle. We present our results in terms of three-dimensional statistics for two-and three-point functions of both galaxy shapes and number counts. In case of the two-point function, we recover the well-known linear alignment result at leading order, but also present the full next-to-leading order expressions. In case of the three-point function we present leading order results for all the auto-and cross-correlations of galaxy shapes and densities. We use a spherical tensor basis to decompose the tensor perturbations in different helicity modes, which allows us to make use of isotropy and parity properties in the correlators. Combined with the results on projection presented in a forthcoming companion paper, our framework is directly applicable to accounting for intrinsic alignment contamination in weak lensing surveys, and to extracting cosmological information from intrinsic alignments. 42A.1 Two-point functions 44 A.2 Three-point functions 47 B Fields in Fourier space 50 B.1 Bias expansion and renormalisation of the one-loop power spectrum 55 B.2 Degeneracy of the bias operators 62 B.3 Bias expansion of the tree-level bispectrum 63 C Bias renormalisation for tensor fields 65 1 Explicitly, we writewhere the Dirac delta function ensures the total momentum conservation, and is a consequence of the statistical translation invariance.

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mentioning

confidence: 99%

An EFT description of galaxy intrinsic alignments

Vlah

Chisari

Schmidt

2020

J. Cosmol. Astropart. Phys.

146

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“…Although this effect is weak and difficult to measure, it would be very interesting from a fundamental point of view because it would constitute a test of the locality of the gravitational field equation because it would relate the isotropic part of the tidal shear tensor, which causes a change in size of the galaxy, to the local value of the density δ (Heavens & Joachimi 2011;Alsing et al 2014;Ciarlariello & Crittenden 2016).…”

Section: Cαβγδ (R) Of the Traceless Tidal Shear φαβmentioning

confidence: 99%

Angular ellipticity correlations in a composite alignment model for elliptical and spiral galaxies and inference from weak lensing

Schäfer

2018

Monthly Notices of the Royal Astronomical Society

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We investigate a physical, composite alignment model for both spiral and elliptical galaxies and its impact on cosmological parameter estimation from weak lensing for a tomographic survey. Ellipticity correlation functions and angular ellipticity spectra for spiral and elliptical galaxies are derived on the basis of tidal interactions with the cosmic large-scale structure and compared to the tomographic weak lensing signal. We find that elliptical galaxies cause a contribution to the weak-lensing dominated ellipticity correlation on intermediate angular scales between 40 and 400 before that of spiral galaxies dominates on higher multipoles. The predominant term on intermediate scales is the negative cross-correlation between intrinsic alignments and weak gravitational lensing (GI-alignment). We simulate parameter inference from weak gravitational lensing with intrinsic alignments unaccounted; the bias induced by ignoring intrinsic alignments in a survey like Euclid is shown to be several times larger than the statistical error and can lead to faulty conclusions when comparing to other observations. The biases generally point into different directions in parameter space, such that in some cases one can observe a partial cancellation effect. Furthermore, it is shown that the biases increase with the number of tomographic bins used for the parameter estimation process. We quantify this parameter estimation bias in units of the statistical error and compute the loss of Bayesian evidence for a model due to the presence of systematic errors as well as the Kullback-Leibler divergence to quantify the distance between the true model and the wrongly inferred one.

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Intrinsic correlations of galaxy sizes in a hydrodynamical cosmological simulation

Johnston

Sophia

Sjoerd

et al. 2023

Monthly Notices of the Royal Astronomical Society

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Residuals between measured galactic radii and those predicted by the Fundamental Plane (FP) are possible tracers of weak lensing magnification. However, observations have shown these to be systematically correlated with the large-scale structure. We use the Horizon-AGN hydrodynamical cosmological simulation to analyse these intrinsic size correlations (ISCs) for both elliptical (early-type) and spiral (late-type) galaxies at z = 0.06. We fit separate FPs to each sample, finding similarly distributed radius residuals, λ, in each case. We find persistent λλ correlations over three-dimensional separations 0.5 − 17 h−1Mpc in the case of spiral galaxies, at >3σ significance. When relaxing a mass-selection, applied for better agreement with galaxy clustering constraints, the spiral λλ detection strengthens to 9σ; we detect a 5σ density-λ correlation; and we observe intrinsically-large spirals to cluster more strongly than small spirals over scales ≲ 10 h−1Mpc, at >5σ significance. Conversely, and in agreement with the literature, we observe lower-mass, intrinsically-small ellipticals to cluster more strongly than their large counterparts over scales 0.5 − 17 h−1Mpc, at >5σ significance. We model λλ correlations using a phenomenological non-linear size model, and predict the level of contamination for cosmic convergence analyses. We find the systematic contribution to be of similar order to, or dominant over the cosmological signal. We make a mock measurement of an intrinsic, systematic contribution to the projected surface mass density Σ(r) and find statistically significant, low-amplitude, positive (negative) contributions from lower-mass spirals (ellipticals), which may be of concern for large-scale (≳ 7 h−1 Mpc) measurements.

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Modelling the impact of intrinsic size and luminosity correlations on magnification estimation

Cited by 3 publications

References 47 publications

An EFT description of galaxy intrinsic alignments

An EFT description of galaxy intrinsic alignments

Angular ellipticity correlations in a composite alignment model for elliptical and spiral galaxies and inference from weak lensing

Intrinsic correlations of galaxy sizes in a hydrodynamical cosmological simulation

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