Speaker
Description
Next-generation Cosmic Microwave Background (CMB) experiments — the Simons Observatory (SO) and the LiteBIRD satellite — are designed to measure CMB polarisation with unprecedented precision, targeting primordial B-modes and signatures of new physics beyond the Standard Model. Achieving these goals requires exquisite control of instrumental systematic effects.
This poster presents the first time-domain simulations that include realistic Half-Wave Plates (HWPs) and full-sky beam convolution, produced with the beamconv code. Using these pioneering full-sky time-domain simulations, I investigate how realistic HWP configurations — including frequency-dependent non-idealities — couple with non-ideal beam patterns to generate spurious polarised signals. I show that certain HWP configurations, interacting with realistic beams featuring non-negligible cross-polarisation and sidelobes, produce significant B-mode residuals that must be carefully modelled.
I then present advanced Time-Ordered Data (TOD) simulations within the litebird_sim and sotodlib frameworks, addressing the characterisation of beam systematics for the SO Large Aperture Telescope (LAT) and the impact of Far Sidelobe (FSL) contamination for LiteBIRD.
Finally, I present a first study of how these instrumental systematics propagate into Cosmic Birefringence (CB) measurements — a parity-violating signature predicted in extensions of the Standard Model — using the localisation of D-estimators to quantify their impact on the anisotropic CB power spectrum. Results demonstrate that beam systematics can reach levels comparable to the forecast sensitivity of next-generation experiments, underscoring the critical importance of high-fidelity instrumental modelling for the next decade of CMB cosmology.