Detecting the largest magnets - The universe and the clusters of galaxies
Citations Over TimeTop 13% of 1990 papers
Abstract
Recently, a large sample of rotation measures of galaxies and quasars at various redshifts has been published. This data set has been employed so far for detecting a magnetic field component of about 1.5 μG in the Virgo Supercluster and for placing an upper limit of 0.1 μG for a magnetic field in the Great Attractor Supercluster. Here this data set will be used to test for the existence of an uniform component of a cosmic/intergalactic magnetic field outside clusters of galaxies. From a total of 309 galaxies and quasars with a known redshift and a small intrinsic rotation measure value, an upper limit of about 2 rad m^-2^ is obtained for such a cosmic/intergalactic contribution out to a redshift z of 3.6. From this result, and a mean density of 10^-5^ cm^-3^, an upper limit of 6 x 10^-12^ G follows for the strength of such a cosmic/intergalactic magnetic field outside clusters of galaxies, or an upper limit of 6 x 10^-11^ G for a mean density of 10^-6^ cm^-3^.