Simulated SKA maps from Galactic 3D-emission models

TL;DR

This paper presents simulated 1.4 GHz Galactic emission maps for SKA, analyzing their statistical properties and magnetic field structures, revealing differences between the Galactic plane and high latitudes.

Contribution

It provides detailed simulated maps and analysis of Galactic emission and magnetic fields at SKA frequencies, highlighting spatial and statistical differences across the sky.

Findings

Total intensity is smoother in the Galactic plane than at high latitudes.

RM PDFs are Gaussian-like in the plane but deviate at high latitudes.

Magnetic field structure functions suggest a transition from 2D to 3D turbulence with latitude.

Abstract

(Abridged) We present maps for various Galactic longitudes and latitudes at 1.4 GHz, which is the frequency where deep SKA surveys are proposed. The maps are about 1.5 deg in size and have an angular resolution of about 1.6 arcsec. We analyse the maps in terms of their probability density functions (PDFs) and structure functions. Total intensity emission is more smooth in the plane than at high latitudes due to the different contributions from the regular and random magnetic field. The high latitude fields show more extended polarized emission and RM structures than those in the plane, where patchy emission structures on very small scales dominate. The RM PDFs in the plane are close to Gaussians, but clearly deviate from that at high latitudes. The RM structure functions show smaller amplitudes and steeper slopes towards high latitudes. These results emerge from the fact that much more turbulent cells are passed through by the line-of-sights in the plane. Although the simulated random magnetic field components distribute in 3D, the magnetic field spectrum extracted from the structure functions of RMs conforms to 2D in the plane and approaches 3D at high latitudes. This is partly related to the outer scale of the turbulent magnetic field, but mainly to the different lengths of the line-of-sights.