Using rotation measure grids to detect cosmological magnetic fields: A Bayesian approach
Journal article, 2016

Determining magnetic field properties in different environments of the cosmic large-scale structure as well as their evolution over redshift is a fundamental step toward uncovering the origin of cosmic magnetic fields. Radio observations permit the study of extragalactic magnetic fields via measurements of the Faraday depth of extragalactic radio sources. Our aim is to investigate how much different extragalactic environments contribute to the Faraday depth variance of these sources. We develop a Bayesian algorithm to distinguish statistically Faraday depth variance contributions intrinsic to the source from those due to the medium between the source and the observer. In our algorithm the Galactic foreground and measurement noise are taken into account as the uncertainty correlations of the Galactic model. Additionally, our algorithm allows for the investigation of possible redshift evolution of the extragalactic contribution. This work presents the derivation of the algorithm and tests performed on mock observations. Because cosmic magnetism is one of the key science projects of the new generation of radio interferometers, we have predicted the performance of our algorithm on mock data collected with these instruments. According to our tests, high-quality catalogs of a few thousands of sources should already enable us to investigate magnetic fields in the cosmic structure.

Methods: data analysis

Large-scale structure of Universe


Methods: statistical

Magnetic fields


V. Vacca

Osservatorio Astronomico di Cagliari

Max Planck Society

N. Oppermann

Canadian Institute for Theoretical Astrophysics

T.A. Enßlin

Ludwig-Maximilians-Universität München

Max Planck Society

J. Jasche

Excellence Cluster Universe

Centre national de la recherche scientifique (CNRS)

M. Selig

Ludwig-Maximilians-Universität München

Max Planck Society

IBM Deutschland Research and Development GmbH Sch-naicher Stra-e 220

M. Greiner

Ludwig-Maximilians-Universität München

Max Planck Society

H. Junklewitz

Argelander-Institut für Astronomie

M. Reinecke

Max Planck Society

M. Brüggen

Universität Hamburg

E. Carretti

Osservatorio Astronomico di Cagliari

C. Ferrari

Istituto di Radioastronomia

C. Ferrari

Centre national de la recherche scientifique (CNRS)

A. Scaife

National Radio Astronomy Observatory Socorro

National Radio Astronomy Observatory

Cathy Horellou

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

S. Ideguchi

Ulsan National Institute of Science and Technology (UNIST)

M. Johnston-Hollitt

Victoria University of Wellington

R. F. Pizzo

Netherlands Institute for Radio Astronomy (ASTRON)

H.J.A. Rottgering

Leiden University

T. W. Shimwell

Leiden University

K. Takahashi

Kumamoto University

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 591 Art. no. A13- A13

Subject Categories

Astronomy, Astrophysics and Cosmology



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