Euclid: Field-level inference of primordial non-Gaussianity and cosmic initial conditions

@article{andrews2026euclid,
  title = {{Euclid: Field-level inference of primordial non-Gaussianity and cosmic initial conditions}},
  author = {A Andrews and J Jasche and G Lavaux and F Leclercq and F Finelli and Y Akrami and M Ballardini and D Karagiannis and J Valiviita and N Bartolo and G Cañas-Herrera and S Casas and B.R Granett and F Pace and D Paoletti and N Porqueres and Z Sakr and D Sapone and Nabila Aghanim and A Amara and S Andreon and C Baccigalupi and M Baldi and S Bardelli and D Bonino and E Branchini and M Brescia and J Brinchmann and S Camera and V Capobianco and C Carbone and J Carretero and M Castellano and G Castignani and S Cavuoti and A Cimatti and C Colodro-Conde and G Congedo and C.J Conselice and L Conversi and Y Copin and F Courbin and H.M Courtois and A da Silva and H Degaudenzi and G de Lucia and A.M Di Giorgio and J Dinis and F Dubath and C.A.J Duncan and X Dupac and S Dusini and M Farina and S Farrens and F Faustini and S Ferriol and M Frailis and E Franceschi and S Galeotta and B Gillis},
  journal = {Astronomy \& Astrophysics - A\&A},
  year = {2026},
  month = sep,
  doi = {10.1051/0004-6361/202553802},
  eprint = {2412.11945},
  archivePrefix = {arXiv},
  url = {https://hal.science/hal-04846300v1},
  note = {CC BY 4.0},
}

TY  - JOUR
TI  - Euclid: Field-level inference of primordial non-Gaussianity and cosmic initial conditions
AU  - A Andrews
AU  - J Jasche
AU  - G Lavaux
AU  - F Leclercq
AU  - F Finelli
AU  - Y Akrami
AU  - M Ballardini
AU  - D Karagiannis
AU  - J Valiviita
AU  - N Bartolo
AU  - G Cañas-Herrera
AU  - S Casas
AU  - B.R Granett
AU  - F Pace
AU  - D Paoletti
AU  - N Porqueres
AU  - Z Sakr
AU  - D Sapone
AU  - Nabila Aghanim
AU  - A Amara
AU  - S Andreon
AU  - C Baccigalupi
AU  - M Baldi
AU  - S Bardelli
AU  - D Bonino
AU  - E Branchini
AU  - M Brescia
AU  - J Brinchmann
AU  - S Camera
AU  - V Capobianco
AU  - C Carbone
AU  - J Carretero
AU  - M Castellano
AU  - G Castignani
AU  - S Cavuoti
AU  - A Cimatti
AU  - C Colodro-Conde
AU  - G Congedo
AU  - C.J Conselice
AU  - L Conversi
AU  - Y Copin
AU  - F Courbin
AU  - H.M Courtois
AU  - A da Silva
AU  - H Degaudenzi
AU  - G de Lucia
AU  - A.M Di Giorgio
AU  - J Dinis
AU  - F Dubath
AU  - C.A.J Duncan
AU  - X Dupac
AU  - S Dusini
AU  - M Farina
AU  - S Farrens
AU  - F Faustini
AU  - S Ferriol
AU  - M Frailis
AU  - E Franceschi
AU  - S Galeotta
AU  - B Gillis
PY  - 2026
DA  - 2026/09/01
JO  - Astronomy & Astrophysics - A&A
DO  - 10.1051/0004-6361/202553802
UR  - https://hal.science/hal-04846300v1
AB  - A primary target of the \Euclid space mission is to constrain early-universe physics by searching for deviations from a primordial Gaussian random field. A significant detection of primordial non-Gaussianity would rule out the simplest models of cosmic inflation and transform our understanding of the origin of the Universe. This paper forecasts how well field-level inference of galaxy redshift surveys can constrain the amplitude of local primordial non-Gaussianity (f_NL), within a Bayesian hierarchical framework, in the upcoming \Euclid data. We design and simulate mock data sets and perform Markov chain Monte Carlo analyses using a full-field forward modelling approach. By including the formation history of the cosmic matter field in the analysis, the method takes into account all available probes of primordial non-Gaussianity, and goes beyond statistical summary estimators of f_NL. Probes include, for example, two-point and higher-order statistics, peculiar velocity fields, and scale-dependent galaxy biases. Furthermore, the method simultaneously handles systematic survey effects, such as selection effects, survey geometries, and galaxy biases. The forecast shows that the method can reach precision levels of up to σ (f_NL) = 2.3 (68.3% CI, and at the grid resolution Δ L = 62.5 h^−1Mpc) with \Euclid data. We also provide data products, including realistic N-body simulations with nonzero values of f_NL and maps of adiabatic curvature fluctuations. The results underscore the feasibility and advantages of field-level inference to constrain f_NL in galaxy redshift surveys. Our approach consistently captures all the information available in the large-scale structure to constrain f_NL, and resolves the degeneracy between early-universe physics and late-time gravitational effects, while mitigating the impact of systematic and observational effects.
SN  - 0004-6361
SN  - 1432-0746
ER  -