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.
Magnetic fields
Large-scale structure of Universe
Polarization
Methods: statistical
Methods: data analysis
Author
V. Vacca
Max Planck Society
Istituto nazionale di astrofisica (INAF)
N. Oppermann
Canadian Institute for Theoretical Astrophysics
T.A. Enßlin
Max Planck Society
Ludwig Maximilian University of Munich (LMU)
J. Jasche
Centre national de la recherche scientifique (CNRS)
Ludwig Maximilian University of Munich (LMU)
M. Selig
Ludwig Maximilian University of Munich (LMU)
IBM Deutschland Research and Development GmbH Sch-naicher Stra-e 220
Max Planck Society
M. Greiner
Max Planck Society
Ludwig Maximilian University of Munich (LMU)
H. Junklewitz
Argelander-Institut für Astronomie
M. Reinecke
Max Planck Society
M. Brüggen
University of Hamburg
E. Carretti
Istituto nazionale di astrofisica (INAF)
C. Ferrari
Istituto di Radioastronomia
L 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- A13Subject Categories
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/201527291