Map-level baryonification: Efficient modelling of higher-order correlations in the weak lensing and thermal Sunyaev-Zeldovich fields

Kavli Affiliate: Chihway Chang

| First 5 Authors: Dhayaa Anbajagane, Shivam Pandey, Chihway Chang, ,

| Summary:

Semi-analytic methods can generate baryon-corrected fields from N-body
simulations (“baryonification”) and are rapidly becoming a ubiquitous tool in
modeling structure formation on non-linear scales. We extend this formalism to
consistently model the weak lensing and thermal Sunyaev-Zeldovich (tSZ) fields
directly on the full-sky, with an emphasis on higher-order correlations. We use
the auto- and cross- $N$th-order moments, with $N in {2, 3, 4}$, as a
summary statistic of the lensing and tSZ fields, and show that our model can
jointly fit these statistics measured in IllustrisTNG to within measurement
uncertainties, for scales above $gtrsim 1 {rm Mpc}$ and across multiple
redshifts. The model predictions change only minimally when including
additional information from secondary halo properties, such as halo
concentration and ellipticity. Each individual moment is dependent on halos of
different mass ranges and has different sensitivities to the model parameters.
A simulation-based forecast on the ULAGAM simulation suite shows that the
combination of all moments, measured from current and upcoming lensing and tSZ
surveys, can jointly constrain cosmology and baryons to high precision. The
lensing and tSZ field are sensitive to different combinations of the
baryonification parameters, with degeneracy directions that are often
orthogonal, and the combination of the two fields leads to significantly better
constraints on both cosmology and astrophysics. Our pipeline for map-level
baryonification is publicly available at
https://github.com/DhayaaAnbajagane/Baryonification.

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