The Galactic Faraday rotation sky 2020

This page contains the full sky reconstruction results of the paper Hutschenreuter, et al. (accepted, A&A).
If you are only interested in parts of the sky, the Faraday mean and uncertainty maps can also conveniently be accessed via a cutout server at CIRADA.

The results are based on version 8 of the RM catalog compiled by Cameron van Eck (
Additionally, the data of the LOFAR Two-metre Sky Survey (LoTSS) (O’Sullivan et al. (in prep.); 2461 data points), and Johnston-Hollit et al. (in prep.) (68 data points) were also used.

The results are provided as a hdf5 file. See here for information about the hdf5 file format, here for its python interface and here for the astropy fits package documentation.
In the hdf5 case, the component maps consitst of groups for the respective sky maps. Each group again has two hdf5-datasets containing the mean and the corresponding standard deviation.
In the fits case, all data are provided as binary tables.
All maps are presented in Galactic coordinates at a HEALPix resolution of Nside=512 and are stored in RING ordering scheme.
The units of the Faraday maps are rad/m2, the component maps are unitless.

The maps have been updated after the first arxiv version with a better noise estimation technique.
The old files are still available but are considered outdated.

File name Description Data Files (hdf5) Data Files (fits) Data Files (old version, hdf5 only)
faradaysky2020v2 Mean and standard deviation of the reconstructed Faraday sky Download Download Download (old version, outdated)
components2020v2 Mean and standard deviation of the reconstructed component maps Download Download Download (old version, outdated)

The files are provided under the terms of the ODC-By License v1.0.


Sebastian Hutschenreuter

Department of Astrophysics
Heyendaalseweg 135
6525 AJ Nijmegen
The Netherlands


Page last updated on 2021-10-09.