Strong magnetic fields in normal galaxies at high redshifts
Abstract
The origin and growth of magnetic fields in galaxies is still something of an enigma. It is generally assumed that seed fields are amplified over time through the dynamo effect, but there are few constraints on the timescale. It has recently been demonstrated that field strengths as traced by rotation measures of distant quasars are comparable to those seen today, but it was unclear whether the high fields were in the exotic environments of the quasars themselves or distributed along the line of sight. Here we demonstrate that the quasars with strong MgII absorption lines are unambiguously associated with larger rotation measures. Since MgII absorption occurs in the haloes of normal galaxies along the sightline to the quasars, this association requires that organized fields of surprisingly high strength are associated with normal galaxies when the Universe was only about one-third of its present age.
Cite
@article{arxiv.0807.3347,
title = {Strong magnetic fields in normal galaxies at high redshifts},
author = {Martin L. Bernet and Francesco Miniati and Simon J. Lilly and Philipp P. Kronberg and Miroslava Dessauges-Zavadsky},
journal= {arXiv preprint arXiv:0807.3347},
year = {2009}
}
Comments
11 pages, 2 figures, Letter to Nature, accepted. Final version available at http://www.nature.com/nature/journal/v454/n7202/abs/nature07105.html