TY - JOUR

T1 - Euclid preparation XXVIII. Modelling of the weak lensing angular power spectrum

AU - Euclid Collaboration

AU - Collaboration, Euclid

AU - Deshpande, A. C.

AU - Kitching, T.

AU - Hall, A.

AU - Aghanim, N.

AU - Amendola, L.

AU - Auricchio, N.

AU - Baldi, M.

AU - Bender, R.

AU - Bonino, D.

AU - Branchini, E.

AU - Brescia, M.

AU - Brinchmann, J.

AU - Camera, S.

AU - Candini, G. P.

AU - Capobianco, V.

AU - Carbone, C.

AU - Cardone, V. F.

AU - Carretero, J.

AU - Castander, F. J.

AU - Castellano, M.

AU - Cavuoti, S.

AU - Cimatti, A.

AU - Cledassou, R.

AU - Congedo, G.

AU - Conselice, C. J.

AU - Conversi, L.

AU - Corcione, L.

AU - Courbin, F.

AU - Cropper, M.

AU - Silva, A. Da

AU - Degaudenzi, H.

AU - Douspis, M.

AU - Dubath, F.

AU - Dupac, X.

AU - Farrens, S.

AU - Ferriol, S.

AU - Fosalba, P.

AU - Frailis, M.

AU - Franceschi, E.

AU - Fumana, M.

AU - Galeotta, S.

AU - Garilli, B.

AU - Gillis, B.

AU - Giocoli, C.

AU - Grazian, A.

AU - Markovic, K.

AU - Nadathur, S.

AU - Pollack, J.

AU - Pourtsidou, A.

N1 - CC-BY licence for AAM in Acknowledgements

PY - 2024/4/17

Y1 - 2024/4/17

N2 - This work considers which higher-order effects in modelling the cosmic shear angular power spectra must be taken into account for Euclid. We identify which terms are of concern, and quantify their individual and cumulative impact on cosmological parameter inference from Euclid. We compute the values of these higher-order effects using analytic expressions, and calculate the impact on cosmological parameter estimation using the Fisher matrix formalism. We review 24 effects and find the following potentially need to be accounted for: the reduced shear approximation, magnification bias, source-lens clustering, source obscuration, local Universe effects, and the flat Universe assumption. Upon computing these explicitly, and calculating their cosmological parameter biases, using a maximum multipole of $\ell=5000$, we find that the magnification bias, source-lens clustering, source obscuration, and local Universe terms individually produce significant ($\,>0.25\sigma$) cosmological biases in one or more parameters, and accordingly must be accounted for. In total, over all effects, we find biases in $\Omega_{\rm m}$, $\Omega_{\rm b}$, $h$, and $\sigma_{8}$ of $0.73\sigma$, $0.28\sigma$, $0.25\sigma$, and $-0.79\sigma$, respectively, for flat $\Lambda$CDM. For the $w_0w_a$CDM case, we find biases in $\Omega_{\rm m}$, $\Omega_{\rm b}$, $h$, $n_{\rm s}$, $\sigma_{8}$, and $w_a$ of $1.49\sigma$, $0.35\sigma$, $-1.36\sigma$, $1.31\sigma$, $-0.84\sigma$, and $-0.35\sigma$, respectively; which are increased relative to the $\Lambda$CDM due to additional degeneracies as a function of redshift and scale.

AB - This work considers which higher-order effects in modelling the cosmic shear angular power spectra must be taken into account for Euclid. We identify which terms are of concern, and quantify their individual and cumulative impact on cosmological parameter inference from Euclid. We compute the values of these higher-order effects using analytic expressions, and calculate the impact on cosmological parameter estimation using the Fisher matrix formalism. We review 24 effects and find the following potentially need to be accounted for: the reduced shear approximation, magnification bias, source-lens clustering, source obscuration, local Universe effects, and the flat Universe assumption. Upon computing these explicitly, and calculating their cosmological parameter biases, using a maximum multipole of $\ell=5000$, we find that the magnification bias, source-lens clustering, source obscuration, and local Universe terms individually produce significant ($\,>0.25\sigma$) cosmological biases in one or more parameters, and accordingly must be accounted for. In total, over all effects, we find biases in $\Omega_{\rm m}$, $\Omega_{\rm b}$, $h$, and $\sigma_{8}$ of $0.73\sigma$, $0.28\sigma$, $0.25\sigma$, and $-0.79\sigma$, respectively, for flat $\Lambda$CDM. For the $w_0w_a$CDM case, we find biases in $\Omega_{\rm m}$, $\Omega_{\rm b}$, $h$, $n_{\rm s}$, $\sigma_{8}$, and $w_a$ of $1.49\sigma$, $0.35\sigma$, $-1.36\sigma$, $1.31\sigma$, $-0.84\sigma$, and $-0.35\sigma$, respectively; which are increased relative to the $\Lambda$CDM due to additional degeneracies as a function of redshift and scale.

KW - astro-ph.CO

KW - gravitation

KW - Gravitational lensing: weak

KW - cosmological parameters

KW - dark energy

U2 - 10.1051/0004-6361/202346110

DO - 10.1051/0004-6361/202346110

M3 - Article

SN - 0004-6361

VL - 684

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - A138

ER -