Probing magnetic fields with GALFACTS

TL;DR

GALFACTS is a large-scale radio survey using the Arecibo telescope to map cosmic magnetic fields through polarized emission and Faraday rotation, serving as a pathfinder for SKA magnetism studies.

Contribution

The paper introduces the application of RM synthesis to GALFACTS data, detailing practical computational techniques and early results in cosmic magnetism research.

Findings

Development of an RM synthesis pipeline for GALFACTS

Early results demonstrating polarized emission mapping

Insights into Faraday Rotation Measures from diffuse and extragalactic sources

Abstract

GALFACTS is a large-area spectro-polarimetric survey on the Arecibo Radio telescope. It uses the seven-beam focal plane feed array receiver system (ALFA) to carry out an imaging survey project of the 12,700 square degrees of sky visible from Arecibo at 1.4 GHz with 8192 spectral channels over a bandwidth of 300 MHz sampled at 1 millisecond. The aggregate data rate is 875 MB/s. GALFACTS observations will create full-Stokes image cubes at an angular resolution of 3.5' with a band-averaged sensitivity of 90 $\mu$Jy, allowing sensitive imaging of polarized radiation and Faraday Rotation Measure from both diffuse emission and extragalactic sources. GALFACTS is a scientific pathfinder to the SKA in the area of cosmic magnetism. Key to magnetism science with the SKA is the technique of RM synthesis. The technique of RM synthesis is introduced and we discuss practical aspects of RM synthesis including efficient computational techniques and detection thresholds in the resulting Faraday spectrum. We illustrate the use of the technique by presenting the current development of the RM synthesis pipeline for GALFACTS and present early results.