Full-sky Models of Galactic Microwave Emission and Polarization at Sub-arcminute Scales for the Python Sky Model

TL;DR

This paper introduces advanced models of polarized Galactic microwave emission at small scales, integrated into the Python Sky Model, to improve foreground predictions for CMB polarization studies.

Contribution

It develops physically motivated, stochastic models of dust and synchrotron emission at sub-arcminute scales, integrated into PySM, enhancing the realism of Galactic foreground simulations.

Findings

Models show improved agreement with observational data.

The suite of models captures a range of astrophysical complexities.

Implementation into PySM facilitates broader use in CMB research.

Abstract

Polarized foreground emission from the Galaxy is one of the biggest challenges facing current and upcoming cosmic microwave background (CMB) polarization experiments. We develop new models of polarized Galactic dust and synchrotron emission at CMB frequencies that draw on the latest observational constraints, that employ the ``polarization fraction tensor'' framework to couple intensity and polarization in a physically motivated way, and that allow for stochastic realizations of small-scale structure at sub-arcminute angular scales currently unconstrained by full-sky data. We implement these models into the publicly available Python Sky Model (PySM) software and additionally provide PySM interfaces to select models of dust and CO emission from the literature. We characterize the behavior of each model by quantitatively comparing it to observational constraints in both maps and power spectra, demonstrating an overall improvement over previous PySM models. Finally, we synthesize models of the various Galactic foreground components into a coherent suite of three plausible microwave skies that span a range of astrophysical complexity allowed by current data.